Plesiodipsas perijanensis

SYSTEMATICS OF THE ENIGMATIC DIPSADINE SNAKETROPIDODIPSAS PERIJANENSIS ALEMAN

(SERPENTES: COLUBRIDAE) AND REVIEW OFMORPHOLOGICAL CHARACTERS OF DIPSADINI

MICHAEL B. HARVEY1,5, GILSON RIVAS FUENMAYOR

2, JOSE RANCES CAICEDO PORTILLA3, AND

JOSE VICENTE RUEDA-ALMONACID4

1Department of Biological Sciences, Broward Community College, 3501 S.W. Davie Road, Davie, FL 33314, USA2Museo de Biologıa, Facultad Experimental de Ciencias, La Universidad del Zulia, Apartado Postal 526,

Maracaibo 4011, Estado Zulia, Venezuela3Laboratorio de Anfibios, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogota, DC, Colombia

4Coordinador Programa Biodiversidad y Especies Amenazadas, Conservacion Internacional Colombia, Bogota, DC,Colombia, e-mail: [email protected]

ABSTRACT: On the basis of new material from Colombia, we describe external morphology, the hemipenis,osteology, musculature, and visceral morphology of Tropidodipsas perijanensis, a species previously knownfrom the unique holotype and long assigned to Dipsas. Tropidodipsas perijanensis may be the sister species ofall other Dipsadini or the sister species of a clade formed by Dipsas and Sibynomorphus. This distinctiveSouth American species cannot be assigned to Tropidodipsas or to any other genus, and we erect a new genusfor it. Our study of cephalic musculature identified a previously unreported division of the m. levator angulioris and new insertion of the m. intermandibularis posterior superficialis. New characteristics of dipsadinehemipenes were visualized by Alizarin staining. Some osteological characters of Dipsadini supportsynonymization of Sibon and most species of Tropidodipsas, whereas visceral characters and publishedmolecular data suggest that Dipsas, Sibon, and Sibynomorphus form a clade.

RESUMEN: Con base en nuevos ejemplares de Colombia, se describe la morfologıa externa y visceral,hemipenes, musculatura y osteologıa de Tropidodipsas perijanensis. Esta especie conocida previamente solopor el holotipo fue por mucho tiempo asignada al genero Dipsas. Posee caracteres especiales que ladiferencian de todos los generos descritos, por lo que se describe uno nuevo para la ubicacion de esta especie.El estudio sobre su musculatura cefalica identifico una division del m. levator anguli oris y una nuevainsercion del m. intermandibularis posterior superficiales, no indicados previamente para la familiaColubridae. Nuevas caracterısticas de los hemipenes de Dipsadini fueron visualizadas por medio de tincioncon Alizarina. Algunos caracteres osteologicos soportan la sinonimia de Sibon y la mayorıa de las especies deTropidodipsas, mientras que los caracteres de la morfologia visceral y datos moleculares ya publicadossugieren que Dipsas, Sibon y Sibynomorphus forman un clado.

Key words: Dipsas perijanensis; Dipsas sanctijoannis; Lung morphology; Musculature; Osteology;Plesiodipsas new genus; Sibon; Sibynomorphus; Tropidodipsas.

IN RECENT years, several careful studies haverevisited the systematics of Dipsas. Herpetol-ogists discovered two new species (MacCul-loch and Lathrop, 2004; Reynolds and Foster,1992) and redescribed poorly known speciessuch as D. neivai (Porto and Fernandes,1996), D. alternans (Passos et al., 2004), andD. albifrons (Passos et al., 2005). Severalspecies were revalidated in the D. oreas(Cadle, 2005), D. pratti (Harvey and Embert,2008), and D. variegata (Cadle and Myers,2003) groups. Perhaps most importantly,these studies defined a suite of new morpho-

logical characters that can reliably establishspecies boundaries and be used to inferrelationships within Dipsas and other Dipsa-dini.

Aleman (1953) described Tropidodipsasperijanensis on the basis of a single femalefrom 1700 m on the Venezuelan slopes of theSerranıa de Perija. When Peters (1960)reviewed the Dipsadini, he did not considerT. perijanensis. Later, Peters (1970) verifiedAleman’s report of 19–17 dorsal scale rowsand referred this species to the D. polylepisgroup. As Peters (1970) acknowledged, themembers of the D. polylepis group were aheterogenous assemblage of seemingly unre-lated snakes sharing 17 or more scale rows at5 CORRESPONDENCE: e-mail, [email protected]

Herpetological Monographs, 22, 2008, 106–132

E 2008 by The Herpetologists’ League, Inc.

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midbody, whereas species in his other groupshave 15 or 13 scale rows at midbody, usuallywithout reduction. After Peters’ (1960) revi-sion, the D. polylepis group was systematicallydismembered. Its species were referred toother genera (Downs, 1961; Hoge, 1964;Fernandes et al., 1998) or shown to normallyhave 15 dorsal scale rows (Fernandes et al.,2002; Harvey and Embert, 2008). Tropido-dipsas perijanensis remained an enigma sinceno new specimens were collected, and Peters(1970) and Aleman (1953) were the onlyauthors to examine and comment on theunique holotype.

Lying along the politically unstable borderof Colombia and Venezuela, the Serranıa dePerija has remained largely unexplored untilvery recently. The Sociedad de CienciasNaturales La Salle, Caracas, conducted limit-ed herpetological surveys in the late 1940s andearly 1950s (Aleman, 1953). Then from 1989to 1991, three expeditions led by the Museode Biologıa de la Universidad del Zuliadiscovered new species of Anolis and Atractus(Barros, 2000; Barros et al., 1996). Finally, inthe late 1990s, field parties from the Museo dela Estacion Biologica de Rancho Grandediscovered species previously recorded fromthe Colombian side of the Serranıa, butunreported for Venezuela (Harvey et al.,2004; Manzanilla et al., 1998, 1999; Rivas etal., 2002). Meanwhile, herpetologists begansurveying lower slopes on the Colombian sideof the Serranıa (Hernandez-Ruz et al., 2001)and two new species of Eleutherodactyluswere discovered (Lynch, 2003).

While reviewing South American Dipsas(Harvey and Embert, 2008), Harvey discov-ered a specimen of Tropidodipsas perijanensisin the California Academy of Sciences andseveral additional specimens were collectedaround Bucaramanga, Santander, Colombia.External anatomy of these snakes immediatelysuggested to us that T. perijanensis had beenwrongly assigned to Dipsas. We take thisopportunity to revisit the species’s systematicsand provide a more thorough descriptionbased on the holotype and new specimensfrom Colombia.

Content of the subfamily Dipsadinae andtribe Dipsadini has changed over time andusage of these names has been inconsistent.

Although Peters (1960) narrowly defined theDipsadinae as containing only the generaDipsas, Sibon, and Sibynomorphus, recentauthors usually considered it to includegenera referred to as ‘‘Central Americanxenodontines’’ by Cadle (1984a, b, c; Cadleand Greene, 1994). Other authors (e.g.,Fernandes, 1995; Ferrarezzi, 1994), prefer torecognize this entire clade as a tribe (‘‘Dipsa-dini’’), considering that it is likely part of alarger clade of xenodontine snakes. Wallach(1995) proposed that the tribe Dipsadiniinclude only Dipsas, Sibon, and Sibynomor-phus. Nonetheless, he appreciated that Tro-pidodipsas is the sister group of his morerestricted tribe. More recently, Zaher (1999)included all four genera in the Dipsadini. Ouruse of these terms is equivalent to that ofZaher (1999) in recognizing Dipsadinae as alarge subfamily containing the genera ofCadle’s ‘‘Central American xenodontines’’and Dipsadini as a tribe containing Dipsas,Sibon, Sibynomorphus, Tropidodipsas, and anew genus described herein. The Dipsadinaeis nested within a larger radiation of xeno-dontine snakes and its formal recognitionrenders Xenodontinae paraphyletic (Lawsonet al., 2005). Both Zaher (1999) and Lawson etal. (2005, their table 5) list genera included inthe Dipsadinae.

MATERIALS AND METHODS

Morphological characters.—We measuredsnout-vent length (SVL) and tail length with astring and meter stick to the nearest 1 mm.With a dial caliper, we measured head length(from the posterior tip of the last supralabialto the center of the rostral), eye-nostrildistance (from the anterior border of the orbitto the center of the nostril), eye-diameter,loreal length (along its ventral margin),greatest loreal height, greatest chinshieldlength, greatest chinshield width, length ofthe heart, snout-heart interval (from the tip ofthe snout to the posterior tip of the heart),heart-liver gap (from the posterior tip of theheart to the anterior edge of the liver), lengthof the liver, and distance between theposterior tip of the liver and anterior edge ofthe gall bladder.

We include the nuchal blotch in counts ofbody blotches, whereas we include a blotch

2008] HERPETOLOGICAL MONOGRAPHS 107

straddling the vent in counts of caudalblotches. When characterizing relative blotchlength on the anterior body, we counteddorsal scales along the sixth dorsal row. Wethen generated a blotch-interblotch ratio(Harvey and Embert, 2008) by averagingcounts from the second and third blotchesand dividing the average by an average ofcounts from the second and third inter-blotches. We counted ventrals using Dowl-ing’s (1951) method. We use the term‘‘chinshields’’ to refer to the large paired,subequal scales between the preventrals andfirst few infralabials in medial contact. Ourdefinition includes scales sometimes referredto as gulars or divided preventrals and isconsistent with Peters’ (1960) use of the term.In the species account, ranges are separatedby a dash, whereas a backslash (/) is used toseparate counts from different sides of thesame specimen. Where appropriate, means 6standard deviation and sample size followranges and character frequencies. Whentabulating descriptive statistics, each countwas treated as a separate observation. There-fore, sample sizes given for paired charactersof pholidosis (e. g., supralabials, preoculars,etc.) refer to the number of sides examined forall specimens, whereas sample sizes given forother (non-paired) characters (e. g., dorsals,ventrals, etc.) refer to the number of snakespecimens examined.

Sex was determined by subcaudal incisionor by inspection of the viscera in specimenswith open abdominal cavities. We routinelyused methylene blue in 70% ethanol toreversibly stain muscle fibers and somestructures such as tiny spines at the base ofthe hemipenis, tracheal cartilages, and buccalepithelia when counting maxillary teeth.

Our description of hemipenial morphologyuses the terminology of Dowling and Savage(1960), Harvey and Embert (2008), and Myersand Campbell (1981). For Tropidodipsasperijanensis (UIS 1243), a distorted and onlypartially everted organ was removed, softenedin 1% KOH, filled with petroleum jelly, andreturned to ethanol for storage (Pesantes,1994; Myers and Cadle, 2003). When soften-ing the organ, we added Alizarin Red to theKOH solution (see Harvey and Embert, 2008,for a discussion of this procedure). Harvey

and Embert (2008) reviewed hemipenialmorphology of Dipsadini. We compared thehemipenis of UIS 1243 to Dipsadini describedby Harvey and Embert (2008) and to moredistantly related Dipsadinae in the generaAdelphicos (4 species examined), Conio-phanes (1), Geophis (5), Hydromorphus (1),Imantodes (1), Leptodeira (1), and Ninia (2)(Appendix 1).

UIS 1243 was used for a more detailedstudy of this species’s morphology. Prior tothis study, the right maxilla, ectopterygoid,pterygoid, and palatine had been removed andboth of its mandibles had been broken. Wedid not undertake an exhaustive study of themuscles of Tropidodipsas perijanensis. None-theless, we scored characters used in earlierstudies of dipsadine systematics (Fernandes,1995; Savitzsky, 1972) and comment on a fewother characters of musculature that varyamong colubrids and may be useful in futurestudies of dipsadine evolution. We use thenomenclature of Haas (1973) for the jawadductors and the nomenclature of Langbar-tel (1968) for hyoid muscles. After studyingthe cephalic musculature and glands, weremoved the skull, and cleared and stained itwith Alizarin using a modification of theprocedure of Taylor and Van Dyke (1985).We compared UIS 1243 to partially dissectedheads and skeletal material of Dipsas (9species examined), Sibon (4), Sibynomorphus(1), and Tropidodipsas (2) (Appendix 1).

We describe the viscera of UIS 1243 andcompare it to that of other dipsadinesdescribed by Wallach (1995) and Harvey andEmbert (2008). When a left lung and bron-chus were absent, we considered the rightbronchus to begin at the posterior tip of theheart, following the arguments of Wallach(1998). We estimated total number of trachealrings by counting the number of rings in a10 mm strip of the trachea just in front of theheart, then multiplying this ratio by thedistance from the posterior tip of the tracheato the tip of the snout. This method minimizesdamage to the specimen and is preferable toopening the coelom up to the glottis. Howev-er, it assumes that tracheal spacing is uniformthroughout and does not account for the shortdistance from the glottis to the tip of thesnout. In many species spacing usually chang-

108 HERPETOLOGICAL MONOGRAPHS [No. 22,

es throughout the length of the specimen(Wallach, unpublished data), and our esti-mates may best be viewed as an index.

Except for CBF (Coleccion Boliviana deFauna, La Paz, Bolivia), MCNC (Museo deCiencias Naturales de Caracas, Caracas,Venezuela), MHNLS (Museo de HistoriaNatural La Salle, Caracas, Venezuela), MIZA(Museo del Instituto de Zoologıa Agrıcola,Maracay, Venezuela), NK (Museo NoelKempff Mercado, Santa Cruz, Bolivia), UIS(Coleccion de Reptiles, Museo de HistoriaNatural, escuela de biologıa, UniversidadIndustrial de Santander, Bucaramanga, Co-lombia), and ULABG (Laboratorio de Biogeo-grafıa, Universidad de Los Andes, Venezuela),museum abbreviations are those of Leviton etal. (1985).

Cladistic methods and diagnoses.—Theevolutionary relationships of the Dipsadinihave yet to be resolved and a phylogeneticanalysis of this group is beyond the scope ofour study. A priori, we did not assumemonophyly of any genus of Dipsadini. Fer-nandes (1995) has already provided evidencethat Dipsas is monophyletic only if Sibyno-morphus is included within it and thatTropidodipsas fischeri is not likely to becongeneric with other Tropidodipsas. Toevaluate possible phylogenetic affinities of T.perijanensis, we compared the species’s mor-phology to species of Dipsas, Sibon, Sibyno-morphus, and Tropidodipsas (Appendix 1).We generated a relatively small matrix ofmorphological characters (Table 2, Appendix2) and use these data to evaluate the mostparsimonious placement of T. perijanensis(determined by hand) within the constrainedalternative dipsadine phylogenetic hypothesesof Kofron (1985) and Dessauer et al. (1986).This exercise also allowed us to consideralterantive evolutionary scenarios of the char-acters described herein.

Character state assignments were based onpublished accounts (see DISCUSSION) andspecimens examined in this study (Appendix2). To polarize characters, we applied themethod of Maddison et al. (1984) to thefollowing hypothesis of outgroup relationshipsto the Dipsadini: ((((((Dipsadini) Adelphicos,Atractus, Geophis, Ninia) Rhadinaea)((Iman-todes, Leptodeira) Tretanorhinus))) Xenodon-

tinae). This conservative and partially unre-solved hypothesis reflects agreement amongthe phylogenetic hypotheses of Cadle (1984a,b, c), Dessauer et al. (1986), Fernandes(1995), and Vidal et al. (2000). Branch supportwas not considered, because we did notreanalyze the data used by Kofron (1985)and Dessauer et al. (1986). Two characters (10and 13) require additional morphologicalstudy, have not been described in outgroups,and were excluded from the phylogeneticanalysis.

In his seminal revision of dipsadine snakes,Peters (1960) did not formulate diagnoses formost species. Our species level diagnosisfollows the numbered format standardizedby Harvey and Embert (2008), whereas thegeneric level diagnosis includes charactersbroadly applicable to snakes within theDipsadinae. Even though the new genus ismonotypic, we provide a species level diagno-sis since investigators will likely confuseTropidodipsas perijanensis with Dipsas. Thespecies level diagnosis allows it to be correctlyidentified without examining internal mor-phology. Previously, the senior author (Har-vey, 1999; Harvey et al., 2003, and Harvey etal., 2005) has discussed reasons for usingstandardized, numbered diagnoses for largecomplex genera of Neotropical snakes.

RESULTS

Tropidodipsas perijanensis cannot be as-signed to Dipsas, because, unlike that genus, itlacks a tracheal lung and has a long heart-livergap, a large Harderian gland, and usually 17dorsals reducing to 15. It cannot remain inTropidodipsas, because it has subrectangularchinshields, has lost the mental groove, lacksan enlarged penultimate supralabial, and lacksa posterior blade-like process on the maxilla.Since this species cannot be placed in anyother genus, we assign it to a new genus.

Plesiodipsas gen. nov.(Figs. 1, 2)

Type species.—Tropidodipsas perijanensisAleman, 1953, by monotypy.

Diagnosis and definition.—Robust bandedsnakes probably not exceeding a meter inlength and differing from other Dipsadinae by


the following combination of characters: (1)eyes large, not visible from below, withelliptical pupils; (2) head distinct from neck,with subacuminate snout; (3) chinshieldssubrectangular and mental groove absent; (4)penultimate supralabial not greatly enlarged;(5) no infralabials greatly enlarged; (6) lorealexcluded from orbit by lower preocular; (7)dorsals smooth, without keels or apical pits,usually in 17 rows at midbody reducing to 15;(8) chin tubercles present in males, supra-

cloacal tubercles absent; (9) Harderian glandlarge and rhomboidal, medial to mm. levatoranguli oris and adductor mandibulae externus,pars superficialis; (10) m. levator anguli orisinserting far anteriorly on dentary; (11)maxillary teeth directed inward, lackinggrooves, and decreasing in size posteriorly;(12) posterior blade-like process of maxillaabsent; (13) teeth extending posterior to notchin dorsolateral maxillary lamina; diastema andenlarged fangs absent; (14) pterygoid teethnumerous, reaching posterior point of diver-gence of pterygoids; (15) tracheal lung absent;(16) heart-liver gap large; (17) capitulum ofhemipenis covered in papillate calyces; (18)

FIG. 1.—Plesiodipsas perijanensis. Reproduction oforiginal watercolor by Gabriel Ugueto.

FIG. 2.—Cephalic morphology of Plesiodipsas perija-nensis (Holotype, MHNLS 655) from Jamayaujaina,Serranıa de Perija, Venezuela.


sulcus spermaticus bifurcating within capitu-lum; (19) base of hemipenis encircled by rowsof large spines separated from pair of basalhooks by asulcate patch; (20) nude basalpocket present on lateral side of hemipenis.

Etymology.—The new name is a femininenoun formed by adding the prefix plesio-(derived from the Greek word plesios mean-ing near) to the generic name Dipsas (derivedfrom the Greek word for thirst).

Content and Range.—Plesiodipsas is amonotypic genus currently known only fromthe northeastern Andes of Colombia andSerranıa de Perija of Venezuela.

Plesiodipsas perijanensis (Aleman)

Tropidodipsas perijanensis Aleman, 1953:217.Holotype female (MHNLS 655) from ‘‘Jama-yaujaina, Sierra de Perija’’ Zulia, Venezuela,1700 m (10u009010N, 72u559010W), collectedby Ramon Urbano.

Dipsas perijanensis (Aleman): Peters, 1970:394; Peters and Orejas-Miranda, 1970:88.Diagnosis and definition.—Plesiodipsas

perijanensis is defined by the following char-acters: (1) dorsals usually 17 (occasionally 15,18, or 19) reducing to 15; (2) temporalsexcluded from orbit by postoculars; (3) usuallyone pair of infralabials in contact behindmental; (4) infralabials broadly contacting thirdpair of chinshields; not contacting preventralsor ventrals; (5) loreal taller than long, excludedfrom orbit by lower preocular; (6) prefrontalsexcluded from orbit by upper preocular; (7)dorsal surface of head black with large yellowspots on most scales; (8) labials barred yellowand black; (9) nuchal region like dorsal surfaceof head, black scales with yellow markings;first blotch not reaching rictus, separatedfrom parietals by 4–7 vertebrals; (10) dorsumlichinose with both blotches and interspacesheavily stippled with contrasting pigments;bands edged broadly first in yellow then inblack; (11) blotches usually not completeventrally; longer or equal to interspaces; (12)interspaces heavily stippled, large accessoryblotches absent; (13) venter cream to yellowwith extensive black markings; short black barsinterrupting interspaces anteriorly; (14) ven-trals 188 in males, 186–195 in females; (15)subcaudals 88–92 in males, 79–83 in females;(16) maxillary teeth 16.

Comparisons with Dipsas sanctijoannis andDipsas variegata.—Of the various snakespresent in northern Venezuela and Colombia,Plesiodipsas perijanensis is most likely to beconfused with Dipsas sanctijoannis. Like P.perijanensis, D. sanctijoannis has a lowerpreocular excluding the loreal from the orbit.Among other species of Dipsas, a lowerpreocular normally excludes the loreal fromthe orbit only in D. catesbyi, although thelower preocular may appear as a rare scaleanomaly in other species.

Inspection of Table 1 reveals considerablesimilarity between Plesiodipsas perijanensisand Dipsas sanctijoannis. However, unlike D.sanctijoannis (characteristics in parentheses),P. perijanensis lacks presuboculars (usuallypresent), usually has 17 dorsal scale rowsreducing to 15 (15 reducing or not to 13), andhas more blotches on the body (33–43compared to 21–28) and tail (18–25 comparedto 11–17). Although the anterior blotches areabout the same size, the first blotch liesfurther back on the neck in P. perijanensisthan in D. sanctijoannis. In D. sanctijoannis,the anterior blotches are complete ventrally;however, they fail to meet in P. perijanensis.

Peters (1970) suggested that the holotype ofPlesiodipsas perijanensis might be an anoma-lous specimen of Dipsas variegata. Unlike D.variegata (characters in parentheses), P.perijanensis has a subacuminate snout andeyes not visible from below (snout rounded,eyes protruding and visible from below), 17dorsals usually reducing to 15 (15 dorsalwithout reduction), one pair of infralabials incontact behind the mental (two pairs), infra-labials broadly contacting the second andthird chinshields (sublabials usually separatinginfralabials from second and third pairs ofchinshields on one or both sides), and thepreocular excluding the loreal from the orbit(loreal usually entering orbit). Dipsas varie-gata also has very different coloration. Itsdorsum is light gray or tan with black or brownstreaks and markings. Its labials are light graywith or without narrow dark brown edging,whereas the head and labials of P. perijanensisare black and its labials bear prominent yellowbars.

External morphology.—Plesiodipsas perija-nensis is a robust species reaching 812 mm in


total length. The tail accounts for 21–25% (236 2, 4) of total length in females and 25–27%(2) in males; the head (Fig. 2) is weaklydistinct from the neck, terminates in asubacuminate snout, and accounts for 3.0–3.6% (3.3 6 0.2, 6) of SVL in both sexes.

The internasal suture is sinistral (100%, 3)to the prefrontal suture. Sutures above andbelow the nostril divide the nasal; this scale isdistinct from the first supralabial and overlapsits anterior margin. The loreal is higher thanlong [loreal length 61–103% (77 6 15, 6) ofheight] and excluded from the orbit by a tall,narrow preocular. A small, square preocularinvariably excludes the prefrontals. Presubo-culars are absent (100%, 12). The large eyeaccounts for 19–21% (19 6 1, 6) of headlength; its distance from the nostril accountsfor 19–22% (20 6 1, 6) of head length. Theeye is not visible from below. Behind the eye,1 (8%, 12) or 2 (92%, 12) primary, 2 (8%, 12)or 3 (92%, 12) secondary, and 2 (20%, 10), 3(70%, 10), or 4 (10%, 10) tertiary temporalsseparate the parietals from the supralabials.Modest shortening of the gape partiallyexcludes the tertiary temporals and onespecimen lacks them entirely. Two (100%,12) postoculars completely exclude the tem-

porals from the orbit. This species has 8(100%, 12) supralabials and 10 (8%, 12), 11(58%, 12), or 12 (33%, 12) infralabials. Two(100%, 12, invariably supralabials 4–5) supra-labials enter the orbit. In all specimens (100%,12), a single pair of infralabials is in contactbehind the mental. Usually (67%, 12), infra-labials broadly contact the first three of fourpairs of chinshields; however, they do notcontact the preventrals or ventrals in thisspecies. Less frequently (33%, 12) infralabialsfail to reach the third pair; they always contactthe first two pairs and sublabials (sensuHarvey and Embert, 2008) are absent.

In Plesiodipsas perijanensis, 186–195 (1906 4, 4) ventrals and 79–83 (80 6 2, 4)subcaudals in females and 188 (2) ventrals and88–92 (2) subcaudals in males follow 0–3preventrals. Dorsal counts in this species arehighly variable. UIS 1244 has 15 scale rowswithout reduction. However, most specimens(67%, 12) have 17 scales at midbody reducingto 15. In two specimens, this fusion occurs faranteriorly (74–75 ventrals in front of the vent),in one specimen relatively far posteriorly (27ventrals in front of the vent), and in onespecimen less than one head length in front ofthe vent (6 ventrals in front). In several places

TABLE 1.—Comparison of morphological characters between Plesiodipsas perijanensis and Dipsas sanctijoannis. Mean6 standard deviation then sample size follow ranges in parentheses.

Plesiodipsas perijanensis Dipsas sanctijoannis

Maximum length Male: 812 mm (2) Male: 923 mm (6)Female: 812 mm (4) Female: 701 mm (1)

Tail length/total length Males: 25–27% (2) Males: 23–27% (26 6 1, 8)Females: 21–25% (23 6 2, 4) Female: 25% (1)

Head length/SVL 3.0–3.6% (3.3 6 0.2, 6) 3.0–3.6% (3.2 6 0.2, 6)Eye-nostril/head length 19–22% (20 6 1, 6) 21–26% (22 6 2, 6)Eye diameter/head length 19–21% (19 6 1, 6) 17–25% (22 6 3, 6)Loreal length/height 61–103% (77 6 15, 6) 55–77% (66 6 7, 6)First chinshield width/height 50–94% (68 6 16, 6) 49–147% (108 6 41, 6)Ventrals Males: 188 (2) Males: 182–187 (185 6 2, 7)

Females: 186–195 (190 6 4, 4) Female: 182 (1)Subcaudals Males: 88–92 (2) Males 74–98 (91 6 9, 8)

Females: 79–83 (80 6 2, 4) Female: 80 (1)Dorsals 17 – 15 (or 18–16) n 5 5 15 – 15 n 5 3

15 – 15 n 5 1 15 – 13 n 5 3Presuboculars Absent n 5 12 Absent n 5 1

Present n 5 9Blotches on body 33–43 (37 6 4, 6) 21–28 (24 6 3, 8)Blotches on tail 18–25 (22 6 3, 5) 11–17 (13 6 3, 4)Length of first blotch 4–6 (5 6 1, 6) 4–6 (5 6 1, 6)Distance to first blotch 4–7 (5 6 1, 6) 3–4 (3 6 0, 6)Anterior blotch/interblotch ratio 1.3–3.5 (2.4 6 0.7, 6) 2.0–2.5 (2.1 6 0.2, 6)Maxillary teeth 16 (3) 16–17 (2)


anterior to the reduction site, only 16 scalesare present due to fusion of one of theparavertebral rows to the vertebral scale row.These counts typically extend for only one ortwo rows of dorsals, but a count of 16 dorsalrows may extend for up to about 10 segmentsin some instances. Through loss and fusion ofone or both paravertebral rows, the vertebralsare slightly enlarged on the posterior body.Both Aleman (1953) and Peters (1970)counted 19 scale rows at midbody on theholotype; one of us (G. Rivas) counted 18reducing to 16. Peters (1970) called attentionto the irregular dorsal counts of the holotypewhen he remarked, ‘‘the holotype of T.perijanensis has counts of 19 on most partsof the body, often 18, and occasionally 17.’’

The dorsal scales of this species (includingthose of the neck, body, and tail) are smoothand lack keels or obvious, raised striations.Apical pits are absent from the neck, body,and tail. In both males and females, lenticularscale organs (sensu Harvey and Gutberlet,1995) cover scales of the head and arenumerous on the chin. In males only, distinctchin tubercles are present, elevating the scaleorgans above the surface of the surroundingskin. Supracloacal tubercles are absent.

Overall, the cryptic dorsal pattern ofPlesiodipsas perijanensis is best described aslichenose (Figs. 1, 3). It is a black snake withyellow to yellowish-green markings; virtuallyevery scale on the body has these two colors invarying amounts. On the dorsal surface of thehead, each of the internasals and prefrontalscontains a large yellow blotch, an elongateyellow stripe extends obliquely across eachparietal, and scattered yellow spots mark theremaining scales. The mostly yellow suprala-bials have wide black edges. A distinct nuchalband is absent; instead a few rows of yellowand black scales separate the first blotch fromthe rictus. Four to seven (5 6 1, 6) vertebralslie between the parietals and the first blotch.The chin is mostly cream to yellow althoughmost scales have wide black margins. Alongthe juncture of the chinshields, these marginsform a continuous stripe in some specimens,truncated by white scales before the ventrals.

This species has 33–43 (37 6 4, 6) blotcheson the body and 18–25 (22 6 3, 5) on the tail.Each blotch is edged widely in black and has a

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lightly pigmented center. In both the inter-spaces and centers of blotches, the dorsals areyellow and have a black line down theircenters. However, within the centers of theblotches, these scales are made darker byadditional black edging around each scale.The blotches fuse dorsally to form bands orare staggered along the midline. Ventrallythey are incomplete; although black pigmentis so extensive on the posterior body that theirventral edges cannot be discerned. The firstblotch extends for 4–6 (5 6 1, 6) vertebrals.The anterior blotches are about twice as longas the interspaces and extend for about 4–7dorsal scale rows; the interspaces extend forabout 2–4 dorsal scale rows (blotch/inter-blotch ratio 1.3–3.5, 2.4 6 0.7, 6). Posteriorly,the blotches shorten to 2–3 scale rows and are

shorter than the interspaces. The interspaceslack accessory blotches of any kind and areinterrupted ventrally by black markings.Ventral pigmentation increases posteriorlyand the tail is almost entirely black ventrally.

Hemipenis.—Plesiodipsas perijanensis has acylindrical, bulbous (i.e., not bilobed), andfully capitate hemipenis (Fig. 4). The capitu-lum terminates proximally in a free flapinterrupted by the sulcus spermaticus; a weakcapitular arch is present on the asulcate side.The sulcus spermaticus bifurcates a shortdistance into the capitulum and its branchesform a widely obtuse angle as they extend tothe sides. Each branch gradually terminatesinto the surrounding calyces, stopping on thesides only about half-way to the distal tip ofthe organ. Papillate calyces cover the capitu-lum. Development of the papillae is more orless uniform across the capitulum. About sixrows of papillae located proximally are calci-fied, including all of the papillae proximal tobranches of the sulcus spermaticus. A medialband of four additional rows of papillae (i.e.,10 rows total counted from the flap of thecapitular arch) are calcified on the asulcateside. Additionally, a few papillae in the firstrow distal to the bifurcation of the sulcus arecalcified.

On the asulcate side of the organ, a singlerow of relatively long, straight spines withweakly curved tips is followed by about fourrows of shorter, strongly curved spines.Medially, a broad, asulcate patch interruptsthe spine rows and separates spines of thecapitular arch from a pair of basal hooks. Themedial hook is about half again as large as thelateral hook, and both bear sharply curvedtips. Small spinules cover the base of theorgan, including the asulcate patch. Thespines, hooks, and spinules are all calcified,and long, robust calcified struts support them.Tips of the papillae and the long straightspines are rounded, slightly bulbous, andblunt, whereas tips of the curved spines, basalhooks, and spinules are sharply pointed.

Approaching the sulcus, the number ofspines reduces from four to two on the lateralside and to one on the medial side (i.e., onemedial and two parasulcal spines are presentin this species). Obviously offset parasulcalspines, like those described for other Dipsa-

FIG. 3.—Specimen of Plesiodipsas perijanensis (CAS116319, female, SVL 600 mm) from Socorpa Mission,Cesar, Colombia.


dini (Harvey and Embert, 2008) cannot bediscerned, because the spines increase innumber along a continuous slope on eitherside of the sulcus. A proximal spine three rowsremoved from the sulcus appears to be at

about the same position as the offset spines inother Dipsadini. In this species, the lateralspine in this position is about the same size asthe smaller hook and is slightly larger than itscounterpart on the medial side.

A nude pocket flanked by rounded, fleshywalls begins on the lateral side of the organand curves rather sharply medially to termi-nate at the edge of the asulcate patch. It onlyextends for about one-fourth of the length ofthe everted organ. Three large, curved spinessit atop the sulcate wall of the pouch, whereasonly spinules cover the asulcate wall. The floorand lower walls of the pouch are entirelynude. A few spinules appear at the upperreaches of the walls of the pouch.

Visceral morphology.—The trachea consistsof about 218 (i.e., 17 cartilages lie within a10 mm stretch in front of heart) narrowlyspaced, cartilaginous rings, very few of whichbifurcate or fuse laterally. Right and leftbronchi are absent, and a small (5.8 mm,1.0% of SVL), entirely faveolar left lung(Fig. 5) attaches to a left tracheal orifice justanterior to the apex of the heart. A tracheallung is absent, although the cartilages do forma trough embracing about one-half to three-quarters of the trachea. Thus, as in mostsnakes, the trachea opens dorsally into atracheal ‘‘chamber’’ continuous with the rightlung. Faveoli extend into the cardiac region,grade into trabeculae, then disappear alltogether about 3 mm in front of the heart.The tracheal chamber does not appear to bevascularized (numerous branches of the pul-monary artery and vein are evident on theventral surface of the right lung, but areabsent from the trachea). Unlike the tracheallungs of Dipsas and Sibon, the walls of thetracheal chamber are not distended andextensible. Within the right lung, faveoliextend for 26.2 mm (4.4% of SVL; extenton either side of liver not asymmetrical)before grading into the saccular portion ofthe lung.

In this specimen, the snout-heart interval(128 mm) accounts for 21.5% of SVL. Theheart is 14.5 mm (2.4% of SVL) long, and agap of 42.8 mm (7.2% of SVL) separates itfrom the liver. The liver extends for 168 mm(28.2% of SVL) and lies 50.3 mm (8.4% ofSVL) in front of the gall bladder.

FIG. 4.—Sulcate (A) and asulcate (B) surfaces of thehemipenis of Plesiodipsas perijanensis (UIS 1243) withcalcified structures revealed by Alizarin staining.


Cephalic glands and musculature.—Thepremaxillary gland (Fig. 6) is triangular andextends dorsally to overlap the anterior edgesof the nasal bones; ventrally it fuses with thelong, narrow supralabial gland below thenaris. A small, oval-shaped gland lies pos-tero-ventral to the naris overlapping the upperedge of the supralabial gland. This structure(presumably the juxtanarial gland describedby Savitzky, 1972, for Chersodromas, Ninia,and Nothopsis) may be part of the supralabialgland; however, it is a shade darker in colorand its superficial epithelium contains densermelanophores than does adjacent epitheliumof the supralabial gland. A large, rectangularnasal gland edges the naris and the prefrontal,frontal, and nasal bones; ventrally it reaches aline drawn from the center of the naris to thecenter of the eye and it is widely separatedfrom the supralabial gland. The small, ovalrictal gland is an inconspicuous structureclosely adhering to extensible skin of the

rictus, just below the quadratomaxillary liga-ment. Circular pores in skin overlying therictal gland may drain this structure, althoughducts could not be distinguished with astereoscope.

The Harderian gland is massive and rhom-boidal; at either end, it posses prominent,oval-shaped swellings, each projecting lateral-ly between overlying muscles and, thus, visibleexternally when the skin is removed. Theanterior swelling of the Harderian glandextends into the triangular space betweenthe antero-ventral edge of the m. levatoranguli oris and postocular ligament; whereas,the posterior swelling abuts the rictal glandwhere the swelling extends into the spacebetween the m. adductor mandibulae externus,pars superficialis, and m. levator anguli oris.Except for these swellings, the Harderian glandlies medial to the m. levator anguli oris and m.adductor mandibulae externus (including parssuperficialis and pars medialis), filling most ofthe concave space between the prootic andorbit. Finally, the Harderian gland has a broadflat anterior expansion, extending into the orbitto encircle the lower two-thirds of the medialside of the eye and cupping the entire ventralsurface of the eye between the eye and palato-maxillary arcade. Plesiodipsas perijanensislacks a Durvenoy gland.

At the corner of the jaw, the m. constrictorcolli separates the quadratomaxillary ligamentfrom the skin, and the ligament can no longerbe distinguished from the quadrate aponeu-rosis (sensu Rieppel, 1980) at the level of thequadrate. Nonetheless, the ligament is distinctfrom the aponeurosis just anterior to the m.depressor mandibulae. Anterior to the m.constrictor colli, the quadratomaxillary liga-ment adheres closely to skin overlapping them. adductor mandibulae externus, pars super-ficialis, and m. levator anguli oris. In fact,several fibers branch off dorsally from theligament and insert firmly on the basementmembrane of the dermis in this region of thehead. The ligament then extends medial to thesupralabial gland to loop around the m.levator anguli oris and continue under thebraincase where it attaches to the posterioredge of the maxilla.

The m. levator anguli oris is unusual inarising by two distinct slips. Except for a few

FIG. 5.—Viscera of Plesiodipsas perijanensis (UIS 1243).


fibers attached to the anterolateral (postfron-tal) process of the parietal, the anterior slip ofthe m. l. a. oris arises from the lateral face ofthe postorbital ligament and postorbital bone.Fibers accounting for the antero-ventral one-sixth of the muscle pass deeply to arise fromthe medial face of the postorbital bone. Theanterior slip edges the m. adductor mandib-ulae externus, pars superficialis, and passesmedial to the quadratomaxillary ligament andrictal gland. The posterior slip might easily bemistaken for the m. a. m. e., pars medialis,because it overlaps the anterior one-half ofthis muscle’s fan-like origin. Medial to the m.a. m. e., pars superficialis, the fibers of theposterior slip and the fibers of the m. a. m. e.,pars medialis, diverge, the latter passingposterior to the lateral expansion of theHarderian gland and those of the posteriorslip passing anterior to the lateral expansion.The two slips of the m. l. a. oris fuse medial tothe infralabial gland and insert far anteriorlyvia a short tendon (beginning between dentaryteeth 5–7, counted from the anterior tip ofmandible backward) on the ventral edge ofthe dentary below teeth 3–5.

The m. adductor mandibulae externus, parssuperficialis, arises from the edge of theanterolateral process, the lateral edge of theparietal between the origins of the two slips ofthe m. levator anguli oris, and the surface ofthe m. l. a. oris itself. On the anterolateralprocess, the origin is fleshy, although a short,triangular tendon (longest posteriorly) formsmost of the origin of this muscle. The muscleis about 60% larger than the anterior slip ofthe m. l. a. oris with which it runs parallel untilthe m. l. a. oris curves sharply anterior aroundthe quadratomaxillary ligament and rictus.Posterior to the rictal gland, the carnoseregion terminates and its aponeurosis fusesto the quadrate aponeurosis to attach alongthe lateral face of the quadrate and retro-articular process of the compound bone.

The m. adductor mandibulae externus, parsmedialis, arises from the lateral edge of theparietal and fascia covering part of the originof the m. a. m. e., pars profundus. The broad,fan-like origin of the m. a. m. e., pars medialis,extends anteriorly for a short distance underthe posterior slip of the m. levator anguli oris.Its fibers extend ventrally and deeply to fill the

FIG. 6.—Subintegumentary, cephalic morphology of Plesiodipsas perijanensis (UIS 1243; m. cervicomandibularis andquadratomaxillary ligament both bisected). Labels identify the quadrate aponeurosis (qa), rictal gland (RG), Harderiangland (HG), supralabial gland (SL), juxtanarial gland (JN), nasal gland (NA), premaxillary gland (PM), m. levator angulioris (loa), m. cervicomandibularis (cer), m. depressor mandibulae (dm), m. intermandibularis posterior superficialis(int), and m. adductor mandibulae externus, pars medialis (med), pars posterior (pos), pars profundus (prf), and parssuperficialis (sup).


space between the Harderian gland andprootic and insert along the medial surfaceof the compound bone. The posterior portionof the insertion is fleshy, and a shortaponeurosis forms the anterior half of theinsertion.

The m. adductor mandibulae externus, parsprofundus, has a narrow origin on the anteriorand dorsolateral face of the prootic, roughly atthe level of this bone’s sutures with theparietal and supratemporal. Its fibers extendventrally, at first paralleling and closelyadhering to fibers on the anterior face of them. a. m. e., pars posterior. About half-way tothe mandible, the fibers of the m. a. m. e., parsprofundus, curve anteriorly to insert along thedorsomedial edge of the compound bonedorsal to and extending more anteriorly thanthe m. a. m. e., pars medialis. The fibers of them. a. m. e., pars profundus, are oriented atabout 10u to those of the m. a. m. e., parsmedialis, and a small portion of the m. a. m. e.,pars medialis, is visible externally through atriangular space between the m. a. m. e., parsprofundus and pars posterior.

Two large muscles covering the quadrateare the m. adductor mandibulae externus, parsposterior, and the m. depressor mandibulae.Both muscles have long fleshy origins fromthe shaft of the quadrate, extending dorsally tofascia covering the supratemporal. The m.depressor mandibulae does not have a discreteoccipital slip. The m. a. m. e., pars posterior,covers the antero-lateral face of the quadrate;it passes medial to the quadratomaxillaryligament and quadrate aponeurosis to form afleshy insertion along the retroarticular pro-cess and compound bone. Its anterior extentabuts the m. a. m. e., pars medialis. The m.depressor mandibulae covers the postero-lateral face of the quadrate and inserts onthe caudal tip of the jaw.

We reached the jaw adductors by firstreflecting the m. constrictor colli, a thinmuscle arising from dorsal fascia along themidline. Its origin overlaps the anterior edgeof the m. cervicomandibularis, which appearsto extend as far anteriorly as the fourthvertebra (its anteriormost fibers arise fromjust below the fourth vertebral scale when theskin is in place). The origin of the m.cervicomandibularis extends posteriorly to

the level of the tenth vertebral scales behindthe parietal scales. Its fibers converge to inserton the posterior tip of the mandible, ventral tothe insertion of the m. depressor mandibulae,and along the posterior edge of the quad-ratomaxillary ligament. The insertion is ori-ented at about the same angle as the quadrateand its fibers are oriented along a line drawnbetween the m. a. m. e., pars posterior, and m.depressor mandibulae.

Although we did not dissect the mandibularand hyoid muscles, we nonetheless noted apeculiar condition of the m. intermandibularisposterior superficialis. This long, strap-likemuscle arises from the depressed area ventralto the retroarticular process on the lateral faceof the compound bone. In contrast to thecondition in most colubrids (Langebartel,1968), the fibers extend anteriorly to insertby a series of slips across the center of each ofthe three anterior chinshields. It does notinsert on a fourth pair of chinshields.

Osteology.—The skull of Plesiodipsas peri-janensis resembles that of other Dipsadini(Fernandes, 1995; Kofron, 1980, 1982, 1985;Scott, 1967). In this section, we focus oncharacteristics mentioned in other reviews ofdipsadine osteology. Previous authors reliedheavily on dentigerous bones when makingcomparisons among Dipsadini, and we de-scribe these bones in detail. During clearingand staining, several bones became disarticu-lated and the postorbitals were lost. Theirdescription is based on observations madewhile studying the jaw musculature.

Braincase: The dorsal lamina of the nasal(Fig. 7) is subtriangular and narrowly overliesthe frontal; it is widely separated from theprefrontal. The ventral lamina deepens pos-teriorly so that a wide space separates it fromthe ascending process of the premaxilla. Thefrontal is subrectangular and a little more thanone-half the length of the parietal. It extendsto the posterior one-fourth of the orbit. Therelatively small optic fenestra occupies aboutone-fourth of the height of the fronto-parietalarticulation inside the orbit. The fenestra ispositioned ventrally in the orbit, closelyapproximating but not bordering the sphe-noid. The parietal has a prominent postorbitalprocess excluding the frontal from the thin,blade-like postorbital bone. The anterior edge


of the parietal is slightly curved where itarticulates with the frontal. Low dorso-lateralcrests on the parietal extend posteriorly fromthe postorbital process and demarcate originsof the adductor muscles. The relatively short,wide sphenoid has a trough-shaped anteriorprocess, terminating in a single point.

Palato-Maxillary Arcade: A thin, dorsallyrounded ascending process of the premaxillaends about 1 mm below the nasals. It forms athin partition between the nasal capsules andextends posteriorly for a short distancebetween the vomers. Ventrally, the anterioredge (5center and transverse processes) ofthe premaxilla is shallowly concave. A prom-inent, acutely pointed process extends belowthe maxilla-premaxillary articular surface atthe ends of each transverse process. Thevomers are firmly braced atop a relativelyrobust vomerine process of the premaxilla.This process bears an acute V-shaped notchbetween the vomers, posteriorly.

The maxilla (Fig. 8) is a short bone bearing16/16 long, curved teeth and three laminae. A

robust palatine articular process extends alongthe anterior extent of the maxilla; it abruptlynarrows and terminates between the 10th and11th maxillary teeth. The dorso-lateral laminaarticulates with the prefrontal and is orientedlaterally at about 70–80u to the palatinearticular process. It begins just behind theseventh tooth and extends to the terminus ofthe maxilla. It widens gently to the level of the14th tooth, narrows to form a wide shallownotch (herein referred to as the ‘‘lateralmaxillary notch’’), then widens slightly whereit articulates with the lateral process of theectopterygoid. This lateral maxillary notch liesjust anterior to the lateral ectopterygoidarticular process and between the last twomaxillary teeth. Thus, whereas teeth do notextend beyond the notch in many Sibon andTropidodipsas (Kofron, 1980), one tooth lies

FIG. 7.—Braincase of Plesiodipsas perijanensis (UIS1243).

FIG. 8.—Elements of the palato-maxillary arcade ofPlesiodipsas perijanensis (UIS 1243). Abbreviations infigure of pterygoid and ectopterygoid (A, ventral aspect)identify the antero-lateral process of the ectopterygoid(ale) and antero-medial process of the ectopterygoid(ame); abbreviations in figure of maxilla (B, ventro-lateralaspect) identify the palatine articular process (pap), dorso-lateral maxillary lamina (dll), lateral maxillary notch (lmn),lateral ectopterygoid articular process (lep), postero-medial maxillary lamina (pml), post-dental maxillary ridge(pdr); and abbreviations in figure of palatine (C, medialaspect) identify the dorso-lateral palatine lamina (dpl) anddorsal process of the palatine (dpp).


posterior to it in Plesiodipsas perijanensis. Adistinct, blade-like postero-lateral process likethat described by Kofron (1980; 1985) andScott (1967) is absent. A wide, short postero-medial lamina articulates with the medialprocess of the ectopterygoid and extends fromthe posterior tip of the maxilla to the anterioredge of the penultimate maxillary tooth. A lowridge of bone (post-dental maxillary ridge)behind the last tooth demarcates the lateralborder of the postero-medial maxillary lamina.

The ectopterygoid is a short, edentate,Y-shaped bone. Its anterolateral process istwo times as wide as its anteromedial process.The shaft of this bone is cylindrical. Posteri-orly, it bears a tab-like process articulatingwith the dorsal surface of the pterygoid.Plesiodipsas perijanensis has a long, well-developed pterygoid bearing 18/18 teeth alongits medial edge. This bone is concave ventro-laterally and widest posteriorly. The ptery-goids are weakly divergent posteriorly (sensuPeters, 1960) and toothed to the point ofdivergence. They extend to the quadrate butdo not articulate with it. The palatine bears10/11 teeth and is a long, narrow element. Ithas a robust dorso-lateral lamina firmlyarticulating with the palatine articular processof the maxilla and a long, narrow, arch-shapeddorsal process extending to the ventral surfaceof the braincase. At the tip of this process, thepalatine bears a short, peg-like articulationwith the posterior process of the vomer.

Teeth of the palato-maxillary arcade anddentary are curved and lack grooves. Theydecrease in size posteriorly; abrupt transitionsin size and diastemas are absent. The lastdentary tooth is only about one half as long asthe first, and teeth of the posterior process ofthe dentary are rotated inward to about 60u ofhorizontal, whereas teeth of the anterior halfof the dentary are oriented vertically. As inmost other Dipsadini, the maxillary teeth ofPlesiodipsas perijanensis are directed ventro-medially at about 30u to vertical.

Suspensorium and Mandible: The dorsalhead of the quadrate is wider than the shaftdue mainly to an expanded dorso-posteriorcrest, which articulates with the supratem-poral bone. The greatest width (along thedorsal edge of the quadrate-supratemporalarticular surface) of the quadrate is one-half

its greatest length. The head of the quadrate isslightly larger than the supratemporal bonewith which it articulates. On the lateral face ofthe quadrate, a low, ventro-lateral ridge(Fig. 9) extends for a short distance abovethe condyle. The supratemporal is reducedrelative to other xenodontines (Fernandes,1995) and extends anteriorly for about three-fourths of the length of the prootic, terminat-ing where it abuts the posterior edge of raisedbone forming the anterior semicircular canal.Posteriorly, the supratemporal overlies raisedbone of the posterior semicircular canalpassing through the exoccipital.

The mandible is very weakly curved in thevertical plane. The dentary is relatively thin;

FIG. 9.—The quadrate and mandible (both in lateralaspect; mandible broken in half) of Plesiodipsas perija-nensis (UIS 1243). Abbreviations identify the angularcrest (anc), dorsal head of the quadrate (dhq), dorso-posterior crest (dpc), posterior maxillary process (pmp),retro-articular process (rap), splenial (spl), and ventro-lateral ridge (vlr).


its posterior process accounts for 60% (mea-sured from the anterior tip of the compound-dentary pivot joint to tip of dentary) of itslength. A pivot joint between the dentary andcompound bone likely allows some abductionof the dentary, because the joint is open onthe lateral face of the mandible. Medially, theangular and splenial border the joint, possiblypreventing adduction. The angular forms theposterior edge of the anterior mandibularforamen and sends a short process above itonto the compound bone, just behind itsarticulation with the dentary. The splenialforms the ventral margin of the mandibularforamen and extends forward to partiallyenclose the Meckelian fossa for about one-half its length. The splenial does not contactthe low ridge of the dentary forming thedorsal border of the fossa. The surangularcrest is slightly larger than the angular crestand flares outward at about 80u to horizontal.In contrast, the angular crest is orientedvertically. Plesiodipsas perijanensis has asmall, subrectangular retroarticular process.

Distribution and natural history.—Most ofthe new Colombian specimens come fromhighly disturbed areas between 1400–2100 min the Andes of Santander Department(Fig. 10). These areas were once covered withhumid, upper montane forest, although mostof the original habitat has been cleared.Specimens in the UIS were collected at theedge of pine forests (Pinus patula) or inecotones between pine forest and secondarygrowth. Two specimens were found deadeither on a road (UIS 1228) or in front of amunicipal building (UIS 1211). UIS 1243 wasfound in a coffee plantation, whereas UIS1244 was collected while it was crossing aroad. J. R. Caicedo P. found UIS 1242 at2036 hrs in forest, the specimen was at restabout 1.5 m above ground in a bush. UIS R-1211 regurgitated a slug when it was killedand preserved.

We do not know if Plesiodipsas perijanensisis arboreal or mostly terrestrial. Enlargedvertebrals and eyes visible from below aretwo characters usually associated with arbore-al Dipsadini; P. perijanensis lacks thesecharacteristics. However, its tail is as long asthe tails of arboreal species such as D.sanctijoannis, and J. R. Caicedo’s observation

of a specimen 1.5 m aboveground in a bushsuggests that this species is at least semiarbo-real.

DISCUSSION

External morphology and hemipenesof Dipsadini.—Aleman (1953) did not elabo-rate on his reasons for assigning Plesiodipsasperijanensis to the genus Tropidodipsas.Familiar with Dipsas variegata and Sibonnebulatus, Aleman likely realized that thisdistinctive dipsadine could not be congenericwith either of these species. Peters (1970)examined the holotype and noted the sub-rectangular chinshields and absence of amental groove. However, some of his otherremarks are misleading or incorrect. As isevident in Aleman’s (1953) photo of theholotype, the head is somewhat distorted.The distortion, likely led Peters (1970) to statethat in this species, ‘‘the head is blunt androunded, distinct from neck. The eyes areprominent, positioned laterally, and can beseen from below.’’ These statements would bean accurate description of most Dipsas andSibon; however, they do not correctly describe

FIG. 10.—Known distribution of Plesiodipsas perija-nensis along northern border of Venezuela and Colombia.Areas above 500 m are shaded gray.


P. perijanensis. The eyes of P. perijanensis arenot visible from below, its head is only slightlydistinct from the neck, and its snout issubacuminate.

Occasional specimens of Dipsas, Sibon, andSibynomorphus have 17 dorsal rows (Fer-nandes et al., 2002; Harvey and Embert,2008), and Peters (1970) suspected that thismight be the case with Plesiodipsas perija-nensis. Noting that D. polylepis might be anaberrant specimen of a species in the D. prattigroup, Peters (1970) speculated that P.perijanensis might be an aberrant specimenrelated to D. variegata. Data from our largerseries show Peters’ speculation to be incor-rect. Unlike all other Dipsadini, Plesiodipsasperijanensis usually has 17 middorsal scalerows, normally reducing to 15. Seventeenmiddorsal scale rows normally occur in mostspecies of Tropidodipsas, whereas species ofDipsas, Sibon, and Sibynomorphus have 15 or13 scale rows. Occasional specimens showreduction on the posterior body, but normallythe counts are constant in Dipsas, Sibon,Sibynomorphus, and Tropidodipsas.

Species of Sibon and Tropidodipsas have anenlarged penultimate supralabial, which con-tacts a postocular and the primary andsecondary temporals. These genera retain arelatively well-defined mental groove flankedby pairs of elongate chinshields. In contrast,the penultimate supralabial is not enlarged,the mental groove is lost, and the chinshieldsare more or less rectangular in species ofDipsas and Sibynomorphus. For each of thesecharacters, P. perijanensis unequivocally hasthe traits of Dipsas and Sibynomorphus.

The Dipsadinae share three derived hemi-penial characters (Myers and Cadle, 1994;Zaher, 1999): (1) reduction or loss of biloba-tion, (2) capitation, and (3) bifurcation of thesulcus spermaticus within the capitulum. Onthe other hand, a hemipenial character has yetto be identified as a synapomorphy of theDipsadini. Every potential character we couldthink of also occurs in outgroup taxa. A basalpocket on the lateral edge of the hemipenisoccurs in several dipsadine genera such asAtractus (Schargel and Castoe, 2003; Myers,2003) and Geophis, Leptodeira, and Ninia(this study). Spines encircle the base ofhemipenes in several dipsadine genera, as

well as in various Xenodontinae. Basal hooksseparated by an asulcate patch occur inGeophis and Ninia. One or two offset para-sulcal spines occur in some species of allDipsadinae examined in this study.

Viscera and musculature.—Wallach (1995)observed that Dipsas, Sibon, and Sibynomor-phus share two derived visceral characters: (1) arelatively short heart-liver gap, and (2) a well-developed, tracheal lung. Harvey and Embert(2008) examined additional species of Dipsas,confirmed Wallach’s characters for these spe-cies, and noted that, when present in Dipsas,the left lung is saccular rather than faveolar.Tropidodipsas and Plesiodipsas perijanensislack these derived traits. They have longheart-liver gaps and lack a tracheal lung.Moreover, the left lung of Plesiodipsas is notsaccular, being lined with faveolar parenchyma.

In most snakes, a ‘‘true’’ m. levator angulioris inserts on the rictal plate, as is the case inlizards (McDowell, 1986; Rieppel, 1980;Zaher, 1994). However, a muscle in somedipsadines referred to by the same name (e.g.,Fernandes, 1995; Moro, 1999; Zaher, 1994,1999) inserts on the mandible. Following thesame reasoning voiced by Rieppel (1988) inreference to the Viperidae, the muscle indipsadines is likely to be a subdivision of them. adductor mandibulae externus superficia-lis, which runs parallel to it and inserts next toit in some Dipsadinae such as Adelphicos,Atractus, Chersodromus, Geophis, and Ninia(Fernandes, 1995; Zaher, 1999). This obser-vation further supports suspicions that themuscle has evolved independently in variouscolubroids (Zaher, 1994). Brongersma (1957),Dunn (1951), Haas (1931), and Peters (1960)all appreciated the significance of this muscleand its forward shift to the dentary in theDipsadini. Among species with this anteriorinsertion of the m. l. a. oris, Fernandes (1995)distinguished two different states. He report-ed that Sibon and Tropidodipsas exhibit hischaracter M01(2) (m. levator anguli oris‘‘inserting on the anterior extremity of thejaw and a carnose region extending to theanterior third of the jaw’’), whereas Dipsasand Sibynomorphus exhibit his characterM01(3) (‘‘inserting on the anterior extremityof the jaw with a small tendon’’). Hisobservations expand on observations of earlier


authors and firmly establish insertion of the m.l. a. oris as a synapomorphy of Dipsadini.Unfortunately, Fernandes’ (1995) descriptionsof his characters M01(2) and M01(3) areinadequate, and we do not see any differencebetween them. He failed to use specificlandmarks when defining these charactersreferring to ‘‘the dentary’’ and ‘‘the anteriorextremity of the jaw’’ as though these aredifferent locations. From the definitions wequote above, one might conclude that pres-ence or absence of a ‘‘small tendon’’ differsamong these groups. However, in the sameparagraph, Fernandes writes, ‘‘Sibon posses amore developed muscle, with the tendonreaching close to the anterior extremity ofthe jaw (state 2).’’ The muscle in Plesiodipsasperijanensis is like other species of Dipsadiniin inserting anteriorly on the dentary by ashort tendon.

None of the authors mentioned in thepreceding paragraph report anterior andposterior slips of the m. levator anguli oris.Nonetheless, the posterior slip might easily bemistaken for a part of the m. adductormandibulae externus, pars medialis. We didnot correctly identify the posterior slip untilwe bisected and reflected the m. a. m. e., parssuperficialis. These two distinct slips of the m.l. a. oris are not unique to Plesiodipsasperijanensis. Dipsas catesbyi and D. indicalack them, but they are present in Sibyno-morphus oneilli and Dipsas pavonina. Wewere unable to examine this muscle in otherspecies and further study is required todetermine how widespread the slips are.

Like species of Chersodromus, Enulius,Enuliophis, Geophis, and Ninia (Savitzky,1972, his character P[1]; Fernandes, 1995,his character M01[1], Zaher, 1999), Plesiodip-sas perijanensis has a very large Harderiangland. Interestingly, the gland is small in mostDipsas, Sibon, and Tropidodipsas. A largegland is present in Dipsas catesbyi, D.pavonina, Sibynomorphus neuwiedi, and S.ventrimaculatus; however, the gland of thesespecies is L-shaped (Fernandes, 1995, hischaracter M01[2]) rather than rhomboidal anddoes not reach the m. a. m. e., pars posterior.Among the Dipsadini, only T. fischeri appearsto have a relatively large rhomboidal glandsimilar to P. perijanensis. Savitzky (1972)

observed that the enlarged Harderian glandof niniaform snakes lies internal to the m.adductor mandibulae externus, pars super-ficialis, whereas the much smaller gland ofmost colubrids occupies a triangular spaceventral and anterior to this muscle, justbehind the orbit. Expanding on these obser-vations, Fernandes (1995) observed that Sibonand Tropidodipsas sartori are unique amongxenodontines in having the Harderian glandpositioned lateral to fibers of the m. levatoranguli oris (Fernandes, 1995, his characterM03[1]). In T. fischeri, the gland lies medialto the jaw adductors as it does in P.perijanensis. Also, as in P. perijanensis, themidsection of the m. levator anguli oris isremoved from the jaw leaving a spacebetween the muscle and the orbit where theHarderian gland is visible (Fernandes, 1995,his character M02 [0]) in T. fischeri.

Several additional characters of cephalicmusculature vary among genera of the Dipsa-dinae, but do not vary among the Dipsadini.With other Dipsadini, P. perijanensis shares alateral origin of the m. adductor mandibulaeexternus medialis, pars superficialis, on theparietal (Fernandes, 1995, his character M04[0]; also in all Dipsadinae except Hydromor-phus and Tretanorhinus), a lateral origin ofthe m. a. m. e., pars medialis, on the parietal(M05 [1]; also in many other Dipsadinae), aposterior insertion of the m. a. m. e., parsprofundus (M06 [0]; in all Dipsadinae exceptsome Geophis and Ninia), and the origin ofthe m. cervicomandibularis anterior to the m.neurocostimandibularis (M08 [0]; in all otherDipsadinae except Adelphicos and Atractus;see also Irish, 1981). Although he commentedin passing on the m. adductor mandibulaeexternus, pars superficialis, and the m. levatoranguli oris, Savitzky (1972) only consideredvariation in the m. depressor mandibulae inhis analysis of the niniaform snakes. Plesio-dipsas perijanensis lacks a discrete occipitalhead of the m. depressor mandibulae (Savitz-ky’s, 1972, character R [1]; also found inChersodromus, Ninia, and Nothopsis).

Plesiodipsas perijanensis lacks several char-acters of cephalic musculature reported onlyfrom some species of Dipsas and Sibynomor-phus. In Sibynomorphus and most Dipsas(excluding only D. elegans and D. temporalis


among species examined by Fernandes, 1995),the m. adductor mandibulae externus, parsprofundus, inserts posterior to the level of itsorigin. The insertion is clearly anterior in P.perijanensis and even further anterior thanthe insertion of the m. a. m. e., pars medialis.Several species of Dipsas are the onlyDipsadinae that lack a quadratomaxillaryligament (Fernandes, 1995); however, thisstructure is well developed in P. perijanensis.Fernandes (1995) mentions fibers of the m. a.m. e., pars superficialis, arising from thelateral surface of m. levator anguli oris in D.brevifacies. The triangular tendon of the m. a.m. e., pars superficialis, does attach to theposterior slip of the m. l. a. oris in P.perijanensis; however, Fernandes (1995) didnot distinguish a posterior slip and would havebeen referring to the portion of this musclehomologous with the anterior slip in D.brevifacies.

Although he briefly describes the hyoids ofmany dipsadines, Langebartel (1968) includedonly a single species of Dipsadini (Dipsascatesbyi) in his survey of hyoid musculature.Frustratingly, this species was neither illus-trated nor commented upon in his descriptivesection. Although we did not examine thesegroups of muscles in detail, we describe anunusual condition of the m. intermandibularisposterior superficialis. Langebartel (1968)found this muscle to be variably present insnakes with a parallel hyoid. However, themuscle is usually thin and aponeurotic,whereas it is relatively robust and entirelycarnose in Plesiodipsas perijanensis. Interest-ingly, the muscle inserts laterally by slips onthe chinshields in P. perijanensis, whereas italways inserts on the median raphe in othersnakes (Langebartel, 1968). This muscle didnot attach to a fourth pair of chinshields in ourspecimen. Peters (1960) describes a muscleextending from the postero-ventral margin ofthe mandible diagonally across the chin toattach to the opposite dentary, so that themuscle forms a ‘‘chiasma with its counterpart’’(Peters, 1960). Nothing like this is present inP. perijanensis. Like Peters (1960), we suspectthat the muscle he is describing and the m. i.p. superficialis of P. perijanensis are designedto overcome difficulties associated with feed-ing on snails. Since the fibers of the m. i. p.

superficialis insert on the distinctive rectan-gular chinshields of P. perijanensis, it wouldbe interesting to know if evolution of a newinsertion is correlated with loss of the mentalgroove.

Osteology.—Elements of the palato-maxil-lary arcade have figured prominently indiscussions of dipsadine systematics. Scott(1967) first commented on processes of thepalatine and maxillary. He reported thatTropidodipsas annulifera entirely lacks thedorsolateral process of the palatine and notedthat this process is reduced and probablynever makes contact with the ventral surfaceof the skull in Dipsas gracilis, Sibon nebulatus,T. philippii, Geophis, and Ninia. Whileexamining skulls of various Dipsadini, wenoted considerable variation in processes ofthe palatine and suspect that further study ofthis bone would provide useful phylogeneticinformation. We describe two processes, adorso-lateral lamina articulating with themaxilla and a dorsal process extending to thefloor of the braincase. The processes inPlesiodipsas perijanensis are about the samesize as those in S. nebulatus and D. indica.The dorsal process of D. peruana is a muchlarger shelf of bone, firmly bracing thepalatine against the skull. Like T. annulifera,Sibynomorphus ventrimaculatus lacks thedorsal process, although the lateral lamina iswell developed and articulates with themaxilla in this species.

Plesiodipsas perijanensis lacks the blade-like posterior process of the maxilla found insome Sibon and Tropidodipsas (Fernandes,1995; Kofron, 1980, 1985; Scott, 1967).Although Kofron (1980) reports that both D.brevifacies and D. gaigeae have ‘‘a pro-nounced lateral process on the maxilla,’’ heis referring to the apex of the dorsolaterallamina located in front of the lateral maxillarynotch, whereas the blade-like process ofTropidodipsas and Sibon is located posteriorto the notch. The blade-like process is actuallya modified ectopterygoid articular process; itprovides ventral support to the ectopterygoidand extends laterally as far as the antero-lateral process of the ectopterygoid. Kofron(1985; see also Haas, 1931) reported that thequadrato-maxillary ligament inserts on theblade-like process. In P. perijanensis, the


insertion of the quadrato-maxillary ligamenthas shifted medially to the posterior edge ofthe maxilla, with a few fibers also inserting onthe basement membrane of the dermis.Whereas Kofron (1985) remarked that thequadrato-maxillary ligament ‘‘appears to con-tain muscle fibers,’’ there is no trace of musclefibers in the ligament of P. perijanensis.

Kofron (1985) considered the blade-likeprocess of the maxilla to be a synapomorphyuniting Tropidodipsas and Sibon. Fernandes(1995) confirmed Kofron’s observations andfound this character only in species of Sibonand Tropidodipsas. Wallach (1995) ques-tioned the importance of the character, citingScott’s (1967) report of the process in Dipsasgracilis. Nonetheless, the character in D.gracilis should be confirmed; Scott (1967)may have been referring to a particularly well-developed dorsolateral lamina. The apex ofthe dorsolateral lamina is considerably point-ed and attenuate in some species of Dipsassuch as D. gaigeae (Kofron, 1982; his figure 2).Having examined UMMZ 155635, Fernandes(1995) thought that T. fischeri lacks a blade-like process. We examined UMMZ 155635and suspect that Fernandes reached hisconclusion after examining the specimen’s leftside where the tip of the process has beenbroken off. However, FMNH 20257 andUMMZ 155635 (on the intact right side) bothhave short, acutely pointed blade-like articularprocesses. Sibon carri, and the specimen of T.fischeri (UTA 7715) illustrated by Kofron(1980, his figure 7) have similar short, acutelypointed processes. In contrast, the process ismore distinctly differentiated in other Sibonand Tropidodipsas.

Fernandes (1995) argued that Tropidodip-sas fischeri belongs in its own genus. Thisspecies falls outside the Sibon-Tropidodipsasclade, because it possesses primitive traits forFernandes’ characters M02–M03 (both de-scribing the relationship of the m. levatoranguli oris and the m. adductor mandibulaeexternus pars superficialis to the Harderiangland and orbit) and O18 (orientation of themaxillary teeth; vertical in T. fischeri, turnedinward in other Dipsadini). In front of thelateral ectopterygoid articular process of mostDipsadini, the dorsolateral lamina of themaxilla bears an indentation ranging from a

shallow depression (e.g., Plesiodipsas perija-nensis, T. fischeri, and Sibynomorphus ven-trimaculatus) to a deep notch (e.g., mostSibon and Tropidodipsas; Kofron, 1980,1985). Maxillary teeth extend behind thisdepression in T. fischeri, P. perijanensis, andat least some species of Dipsas (Kofron, 1982)and Sibynomorphus. Some species of Dipsas(e.g., D. indica, D. peruana) and Sibynomor-phus (e.g., S. oneilli) conspicuously lack thenotch; the dorsolateral lamina of the maxillamerges seamlessly with the ectopterygoidarticular process in these species.

Plesiodipsas perijanensis lacks other de-rived osteological features common to varioussubsets of Dipsas such as straight parietal-frontal articular surfaces (Fernandes, 1995,his character O06[1]), a postorbital lateralprocess located immediately behind the fron-tal-parietal articulation (O08[2]), an abruptlynarrowed quadrate (O13[1]), an enlargedoptic fenestra (O16[2]), an enlarged dorsolat-eral lamina (O17[2]), truncate posterior end ofthe pterygoid due to loss of its lateralexpansion (O23[1]), reduced numbers ofpterygoid teeth (O25[1]), and loss of thedorsolateral notch in the maxilla. In additionto the posterior blade-like process, P. perija-nensis lacks some derived osteological featuresof subsets of Sibon and Tropidodipsas such asan enlarged optic fenestra (Fernandes, 1995,his character O16[2]) and loss of the dorsalprocess of the palatine (Scott, 1967).

Hypotheses of Character Evolution andRelationships of Dipsadini.—Plesiodipsasperijanensis possesses a suite of derived andprimitive characters that preclude it from anycurrently recognized genus of Dipsadini.However, its relationships to other generaremain obscure, because the morphologicalcharacters provide contradictory information.To facilitate discussion of the morphologicalcharacters used in dipsadine systematics, wepresent three phylogenetic hypotheses(Fig. 11) depicting the most parsimoniousplacement of P. perijanensis within theconstrained dipsadine phylogenetic hypothe-ses of Dessauer et al. (1986) and Kofron(1985).

Within the dipsadine hypothesis proposedby Dessauer et al. (1986), Plesiodipsas is mostparsimoniously placed as the sister taxon of all


other Dipsadini (Fig. 11A); however, thishypothesis requires that the mental groove,enlarged penultimate supralabial, lateral posi-tion of the Harderian gland, and posterior

blade-like process of the maxilla evolve twice(or be lost secondarily by some Dipsadini).Within the dipsadine hypothesis proposed byKofron (1985), Plesiodipsas is most parsimo-niously placed as either the sister genus ofDipsas + Sibynomorphus (Fig. 11B) or assister to all other Dipsadini (Fig. 11C). Inboth hypotheses, a tracheal lung, short heart-liver gap, and reduction to 13–15 dorsalswould have to evolve twice (or be lost byTropidodipsas in Fig. 11C).

Kofron (1985) synonymized Sibon andTropidodipsas and suggested that T. fischeribe transferred to a new genus. Althoughsubsequent authors generally agreed with hisviews about T. fischeri, his proposal that Sibonand Tropidodipsas are congeneric was sup-ported by Fernandes (1995), was questionedby Savage and McDiarmid (1992), and wasrejected by Wallach (1995). Genetic distancedata (Cadle, 1984b, Dessauer et al., 1986)does not support Kofron’s proposal. Themorphological evidence from our study isambiguous (Fig. 11) with regard to thepossible sister relationship of Sibon andTropidodipsas. These genera share threedistinctive apomorphies (an enlarged penulti-mate supralabial, a posterior blade-like pro-cess of the maxilla and, except for T. fischeri,the Harderian gland positioned lateral to them. levator anguli oris). Except for T. fischeri,the maxillary teeth terminate in front of thedorsolateral notch (Character 10 a, Appendix2) in Sibon and Tropidodipsas. However, wesuspect that this character is not independentof Characters 8. Additional study of theposterior end of the maxilla and its associatedmusculature might help resolve this questionof character independence.

Acknowledgments.—G. Ugueto prepared a watercolorillustration of Plesiodipsas perijanensis (Fig. 1) and O.Villarreal illustrated the cephalic morphology of theholotype (Fig. 2). For loan of specimens under their care,we thank J. W. Arntzen (RMNH), C. Austin (LSUMZ), J.A. Campbell (UTA), R. Feeney (LACM), D. R. Frost andL. S. Ford (AMNH), J. Hanken and J. Rosado (MCZ), J.McGuire (MVZ) R. Nussbaum and G. Schneider(UMMZ), M. P. Ramirez-Pinilla (UIS), S. P. Rogers(CM), R. P. Reynolds (USNM), L. Trueb and W. E.Duellman (KU), and H. K. Voris and A. Resetar (FMNH),and J. Vindum (CAS). T. R. Barros B. (La Universidad deZulia, Venezuela) kindly sent a specimen of D. praeornatato us. During the course of this study, M. B. Harveyvisited three museums in the United States and twomuseums in Bolivia. For providing him with working

FIG. 11.—Three phylogenetic hypotheses of Dipsadini(L 5 15, CI 5 0.73, RI 5 0.50). Character numbers arethose in Table 2 and Appendix 2. Convergent charactersare shaded gray. (A) Intergeneric relationships consistentwith genetic differentiation (Dessauer et al., 1986). (B andC) Intergeneric relationships consistent with Kofron’s(1985) proposal.


space and for their many courtesies during his visit,Harvey thanks D. R. Frost and R. Bain (AMNH); J. A.Campbell, E. N. Smith, and C. Franklin (UTA); M. A.Nickerson, K. L. Krysko, and C. Sheehy (UF); L.Gonzales A. (NK); and J. Aparicio E. (CBF). B. Noonanprovided advice about cladistic methods.

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APPENDIX 1

Specimens Examined

Adelphicos latifascatum.—MEXICO: OAXACA: Colo-nia Rodulfo Figueroa (UTA 12246); Cerro Baul (UTA6213).

Adelphicos nigrilatum.—MEXICO: CHIAPAS: 1.8 kmE Tulanca (UTA 8838); 13.7 km (by road) SE SanCristobal de las Casas (UTA 12248); Cerro Pij (UTA51864).

Adelphicos quadrivirgatum.—GUATEMALA: QUET-ZALTENANGO: S slope Volcan Santa Marıa, Finca ElFarro (UTA 22655, 22671, 22680).

Adelphicos veraepacis.—GUATEMALA: BAJA VER-APAZ: Cerro Verde (UTA 6542, 6551, 6584).

Coniophanes fissidens.—MEXICO: VERACRUZ:2.1 m NW Sontecomopan, by road (UTA 3069); SWslope of Volcan San Martın (UTA 51094); 5.6 mi ESETebanca (UTA 3067).

Dipsas albifrons.—BRAZIL: SAO PAULO: no otherdata (MCZ 20855); SANTA CATARINA: Corupa (UF11597).

Dipsas articulata.—COSTA RICA: ALAJUELA: ‘‘vi-cinity of Muelle San Carlos’’ (LACM 150495); PANDO-RA: Limon (UMMZ 125236); UNKNOWN: ‘‘San Jose’’(AMNH 17370). NICARAGUA: UNKNOWN: ‘‘Atlanticslope eastern Nicaragua’’ (LACM 150496). PANAMA:BOCAS DEL TORO: ‘‘Rıo Changuinola nr Quebrada ElGuabo, 40–100 m’’ (AMNH 124125).

Dipsas bicolor.—COSTA RICA: HEREDIA: ‘‘RioFrio, Standard Fruit Company 10u209N, 83u539W,330 ft’’ (UF 31293).

Dipsas brevifacies.—MEXICO: QUINTANA ROO:‘‘Hwy. 307, 1 km N. of intersection with Puerto MorelosRoad’’ (UF 42072); YUCUTAN: ‘‘Mex. 180, 1.9 mi WValladolid’’ (UF 140801); 2.2 km N Piste (KU 70839 skulland external morphology).

Dipsas bucephala.—BOLIVIA: COCHABAMBA:Campamento Guacharos, 600 m (MHNC-R 890); noother data (AMNH 6780); SANTA CRUZ: Porongo,400–550 m (NK 3070); Finca Dos Milanos, 260–280 m(UTA 38081); Loma alta, 800–1300 m (NK 160); Agua-clara, 1100–2000 m (NK 1220, 1569, 2156); Barrio Nuevo,1200–1900 m (NK 856); Becerro, 1300–2000 m (NK1567); El Millu, 1100–2000 m (NK 3473–3474); El Pacay,1200–1800 m (NK 2201); Mairana, 1400–2000 m (NK1277); Pampagrande, 1200–1900 m (NK 557, 586, 684);

Santa Rosa de Lima, 1500–2200 m (NK 2737, 3516);Buena Vista, 300–400 m (CM 2878, FMNH 16794,35723; UMMZ 63252–63253, 67902–67905, UMMZ149728 skull); ‘‘near Buena Vista, Rıo Colorado’’, 300–400 m (CM 2954); Lago Caiman, Parque Noel KempffMercado, 200–580 m (UTA 52871–52872); specific local-ity unknown (CM 2941).

Dipsas catesbyi.—BOLIVIA: BENI: ‘‘Serranıa Pilon,27 km by road N Rıo Quiquilbay’’, 300–1300 m (LSUMZ45543); Estancia Ojo de Agua, 140 m (UF 68513); TumiChucua, 150 m (USNM 280380); ‘‘vicinity of Guayara-merın’’, 150 m (AMNH 101824); ‘‘Rio Marmore, SantaRosa’’, 160–180 m (AMNH 101825, 101826); Rurrenaba-que, 190–300 m (AMNH 22444); no other data (AMNH2978, 2979, 2980); COCHABAMBA: Altamachi, 930–1770 m (CBGR 0050); Sajta, 230 m (NK 668); Chimore,240 m (NK 439); LA PAZ: Ixiamas, Barraca Santa Rosa,Rio Manuripi, 250–290 m (NK 2123–2124); Ixiamas,Aceradero Bosques del Norte, 250–290 m (CBF 779);Tumupasa, 2500 m (CBF 1903); Valle de Zongo, 1350 m(CBF 1169); Parque Nacional Cotapata, CampamientoSandillani, 1300–3200 m (CBF 2083, 2085); ‘‘Espia, BopiRiver’’, 900–1500 m (AMNH 21245); ‘‘Pelechnes, nor-dostlich von Titicaca’’ (ZMB 10889); PANDO: NuevaEspana, Manuripi Heath, RNAVS, 200 m (NK 2571);SANTA CRUZ: Angostura, 600–1100 m (NK 548); SantaRita, 550–700 m (NK 804); Bermejo, 800–1500 m (NK1562); El Millu, 1100–2000 m (NK 1588); Huachi, 150–200 m (AMNH 22485, 22486, 22444); ‘‘probably BuenaVista’’, 300–400 m (FMNH 35711–16, 35717–22, AMNH35995, ZSM unnumbered); San Ramon, 250–280 m (NK420); ‘‘112 km N of Santa Cruz’’, 230–260 m (AMNH119925); UNKNOWN: locality unknown (ZMB 25929,UMMZ 149727 skull). ECUADOR: NAPO: ‘‘10.9 km. NRio Tiputini’’ (UF 43170); ‘‘3.1 km. S Rio Tiputini’’ (UF43171); Rio Yasuni, Campsite 2 (UF 44288, 44289);SUCUMBIOS: Santa Cecilia (KU 146737 musculatureand external morphology). SURINAME: ‘‘poisonedforest’’ (RMNH 35958), Silpaliwini (UTA 52875).

Dipsas chaparensis.—BOLIVIA: COCHABAMBA:Khara Huasi, 1800–2300 m (UTA 38083); ‘‘Paracti,83.2 km from Cochabamba on road to Villa Tunari’’,2300–3100 m (USNM 257869, holotype); SANTA CRUZ:Algodonal, 1100–1900 m (NK 1864); Bermejo, 800–1500 m (NK 2629); El Chape, 1000–2000 m (UTA38082, 52873–52874); La Hoyada, 1200–2000 m (NK1997, 3065–3066, 3231); Palmasola, 1400–2000 m (NK1861); Palmasola, Yunga del Tontal, 1400–2000 m (NK1732); Santa Rosa de Lima, 1500–2200 m (NK 3360,2736).

Dipsas copei.—VENEZUELA: AMAZONAS: ‘‘SierraParima 3u259N, 64u389W, 1180 m’’ (MHNLS 11972).

Dipsas gaigae.—MEXICO: JALISCO: ‘‘La Huerta,2 km N Zapata (Municipio La Huerta)’’ (UTACV 52573);‘‘on Hwy 200, 34 miles NW of Hwy 80’’ (LACM 136910).

Dipsas gracilis.—ECUADOR: ESMERALDAS: ‘‘Ha-cienda Equinox, 30 km (airline) NNW of Santo Domingode los Colorados, 1000 ft (5 300 m)’’ (USNM 210945);LOS RIOS: ‘‘Estacion Biologica Rıo Palenque, 56 km NQuevedo, 220 m’’ (KU 152604); PICHINCHA: ‘‘14.1 kmSE Patricia Pilar by road’’ (MCZ 156894); Pachijal(USNM 210940); Gualea (USNM 210941); ‘‘Finca LaEsperanza, 4 km W of Santo Domingo de los Colorados’’


(USNM 210942–210944); UNKNOWN: no other data(LACM 2308).

Dipsas elegans.—ECUADOR: PICHINCHA: Tan-dapi, 1520 m (KU 112264 skull and specimen). UN-KNOWN: UNKNOWN: no other data (MCZ 178357).

Dipsas indica ecuadoriensis.—ECUADOR: NAPO:‘‘6.5 km ESE of Puerto Misahualli at La Cruz Blanca onJatun Sacha Biol. Res.’’ (MCZ 173881, 173880); ‘‘Baeza’’(MCZ 164492); 15 km ENE Umbaqui, Bermejo No. 4,740 m (KU 121871 skull and external morphology);PASTAZA: ‘‘Rıo Pastaza, 500 m’’ (UMMZ 89028, para-type); SUCUMBIOS: Santa Cecilia (KU 126023 musclesand external morphology). UNKNOWN: UNKNOWN:no other data (MCZ 178356).

Dipsas indica.—BOLIVIA: PANDO: ‘‘Madre de DiosRiver junction with Rıo Sena’’, 150 m (UMMZ 59774).COLOMBIA: AMAZONAS: Leticia (CM 53500–53503).GUYANA: UPPER TAKUTU-UPPER ESSEQUIBO:‘‘Marudi’’ (AMNH 60857). PERU: CUSCO: ‘‘HuadquinaAndes S. Peru’’ (MCZ 10772); UCAYALI: ‘‘Iparia’’ (MCZ119409). SURINAME: COMMEWIJNE: ‘‘Wederzorg’’(RMNH 5349); ‘‘distr. Saramacca, km 11 Loksihatiweg,Coesewijne Hontvesterij LBB’’ (RMNH 35959).

Dipsas nicholsi.—PANAMA: CANAL ZONE: ‘‘Mad-den Forest Road, 3.9 mi. S. Transisthmus Highway’’ (UF44292); ‘‘Madden Forest Madden Road, 100 ft. N GeorgeGreen’’ (UF 44293); ‘‘Park’’ (44294); ‘‘Madden ForestRoad, 3.2 mi SE Transisthmus Hwy’’ (UF 44295);‘‘Madden Forest Road, 3.3 mi. S Transisthmus Hwy’’(UF 44296); ‘‘Madden Road’’ (44297); ‘‘Madden ForestRoad, 0.9 mi. S Transisthmus Hwy’’ (UF 44298, 44303);‘‘Chiva-chiva Road’’ (UF 44300); ‘‘Madden Forest Road’’(UF 44301, 44302); ‘‘Madden Forest Preserve, 100 m’’(KU 110310, skull and external morphology).

Dipsas oreas.—ECUADOR: LOJA: 13 km E Veracruz(20 km NE Catacocha) 2250 m (KU 142803).

Dipsas pakaraima.—GUYANA: DISTRICT 7: ‘‘MountAyanganna, northeast plateau, 05u249N, 059u579W, 1490m.’’ (ROM 41236).

Dipsas pavonina.—BOLIVIA: LA PAZ: Iturralde:Parque Nacional Madidi, Serranıa El Tigre, Camino AltoMadidi, 250–340 m (CBF 2139). ECUADOR: SUCUM-BIOS: Santa Cecilia (KU 121875 musculature andexternal morphology). GUYANA: DEMERARA-MA-HAICA: ‘‘Dunoon; Demerara River’’ (6u269S, 58u189W)(UMMZ 47747).

Dipsas peruana.—COLOMBIA: BOYACA: ‘‘valley ofRıo Cusiana, 1700 m’’ (KU 110589). ECUADOR:NAPO: ‘‘Rıo Napo’’ (UMMZ 88978–79); ‘‘Rıo Napowatershed’’ (UMMZ 88980); ‘‘immediate environs ofBorja, 5600 ft (5 1670 m)’’ (USNM 210957); Borja(USNM 210958–210959); Coca (MCZ 166589–90); ElReventador (MCZ 164510–11); Lumbaqui (MCZ 164674–75); ‘‘Rio Azuela, where river crosses road from Quito’’(USNM 286323); Rio Cotopino, Upper Rio Napo (USNM210960); PASTAZA: ‘‘Rıo Pastaza, 1800 m’’ (UMMZ88995); ‘‘Rıo Pastaza, 500 m’’ (UMMZ 88996–97); TUN-GURAHUA: ‘‘W slope Cordillera del Condor, E San Jose,1600 m, Morono-Santiago’’ (KU 147196); ‘‘Mapoto,1300 m’’ (UMMZ 88977); ‘‘Banos, 1800 m’’ (UMMZ88984–86); ‘‘Yungurahua, N bank Rıo Pastaza at RıoBlanco, Yungilla, 1700 m’’ (UMMZ 92046); ‘‘S bank RıoPastaza near Banos, 1800 m’’ (UMMZ 92047–48); UN-KNOWN: Banos Abi Taqua (AMNH 24146, 24149);

Palmera (not traced)(AMNH 37939); Llangate (FMNH23532 skull). PERU: AMAZONAS: ‘‘Bongara province,Pomocochas (5Florida), 2150 m’’ (KU 212590); ‘‘28 kmSE Ingenio on road to Laguna Pomacocha’’ (LSUMZ27371–27372); CAJAMARCA: ‘‘Tabaconas, 1892 m,5u199S, 79u189W’’ (MCZ 17404); CUSCO: ‘‘HaciendaHuyro between Huayopata and Quillabamba; aboveplantations; Bosque Aputinye’’ (LSUMZ 27369–70); ‘‘LasRuinas de Machu Picchu, 2400 m’’ (KU 117109);‘‘Paucartambo, Paucartambo, Mirador, 1810 m,13u49110S, 71u339190W.’’ (AMNH 147037); ‘‘1 km (air-line) W Amaybamba’’ (MCZ 178175); Urubamba, Putu-kusi, 2050 m (UTACV 51467); Pucyura (USNM 60718);PASCO: ‘‘Playa Pampa, 8 km NW Cushi on trail toChagalla, 2100 m, 9u579S, 75u429W’’ (LSUMZ 45499,locality amended based on personal communication toCadle by T. S. Schulenberg as cited by Cadle, 2005);PUNO: ‘‘11 km NNE (airline) of Ollachea, 1880 m’’(USNM 299232–299234); SAN MARTIN/LORETO:‘‘Cumbre Ushpayacu-Mishquiyacu, 975 m, 6u579S,76u39W’’ (Cadle, 2005, provides additional informationabout this locality) (AMNH 52444); NOT TRACED:Arubo (FMNH 5597).

Dipsas praeornata.—VENEZUELA: ARAGUA: ‘‘Km24, Maracay-Ocumare de la Costa rd, 870 m’’ (KU167574); ‘‘Km 22.3, Maracay-Ocumare de la Costa Road,0 m’’ (KU 182709); ‘‘Rancho Grande, nr Maracay’’(AMNH 98245–47); Parque Nacional Henry Pittier(MHNLS 17708); DISTRITO FEDERAL: ‘‘FederalDistrict, on rd to Instituto Venezolano de Investig.Cientificas (IVIC), 2 km from Pan Amer hwy, 8 km fromCaracas’’ (UMMZ 203984); LIBERTADOR: Boca deTigre, Parque Nacional El Avila, 1800 m (MHNLS13305); MIRANDA: Curupao, Power Plant (AMNH59452).

Dipsas pratti.—COLOMBIA: ANTIOQUIA: ‘‘RıoNegrito, 15 km E Sonson, 1850 m’’ (FMNH 63758);‘‘Medellin’’ (AMNH 35553); UNKNOWN: ‘‘New Gran-ada’’ (AMNH 17525, Cotype).

Dipsas sanctijoannis.—COLOMBIA: CALDAS:‘‘Pueblo Rico, Santa Cecilia, Pacific side, 1700 m’’(FMNH 54898); CAUCA: ‘‘El Tambo, Munchique,Cauca River side, 2300 m’’ (FMNH 54903–05); ‘‘caPopayan, 1700 m’’ (KU 140403); ‘‘Valle del Cauca, SanAntonio,’’ (MVZ 68694); ‘‘Valle del Cauca. 4 km NW SanAntonio,’’ (MVZ 68695); QUINDIO: ‘‘mts. east ofCalarca, 2000 m’’ (AMNH 106650); VALLE: 24 kmNW Cali, 1800 m (AMNH 106651); ‘‘vicinity of Cali’’(AMNH 106652).

Dipsas temporalis.—COLOMBIA: CHOCO: ‘‘AguaClara, Rıo Tamana, approximately 4u539N, 76u459W’’(USNM 267244); Camino de Yupe (LACM 72745–46);Alto de Buey, N slope (LACM 72747). PANAMA:DARIEN: ‘‘ridge between Rıo Jacque & Rıo Imamado,800 m, 7u359N, 77u579W’’ (KU 110294–110297; skull andexternal morphology of KU 110294); ‘‘N ridge CerroCituro, Serranıa de Pirre, 900 m, 8u59N, 77u469W’’ (KU110298); ‘‘S slope Cerro Cituro, Serranıa de Pirre,1000 m’’ (KU 110299–300); PANAMA: ‘‘S slope CerroLa Campana, 850 m,’’ (KU 110293); ‘‘Pequeni-Chagresridge, head of Rıo Limpio and Quebrada Las TresHoneras (Panama snake census), 9u189N, 79u279W’’(MCZ 50214).


Dipsas trinitatis.—TRINIDAD: ST. GEORGE: ‘‘vi-cinity of milestone 1, Arima–Blanchisseuse Road’’(10u389N, 61u179W) (USNM 166683); ‘‘at turn-off toSimla, Arima Ward, Arima–Blanchisseuse Road’’(10u409N, 61u189W) (USNM 194987); ‘‘between Arimabypass and 7.5 mi N of Arima, on Blanchisseuse Road’’(USNM 252674–252678); ‘‘Arima Valley, 5 mi N ofArima, Arima Ward’’ (10u409N, 61u189W) (UMMZ125790); UNKNOWN: Port of Spain (10u399N,61u319W) (AMNH 73124).

Dipsas variegata.—BOLIVIA: COCHABAMBA: ‘‘Re-serva Altamachi, Serranıa de Mosetenes, 1200 m,16u029270S, 66u389540W’’ (NK uncatalogued); LA PAZ:‘‘Proximo al rıo Quiquibeycito en la senda hacia la serranıade Muchanes, Territorio Indıgena Pilon Lajas’’, 200–500 m (CBF 1127); ‘‘ca 1 mile W of Puerto Linares,360 m’’ (USNM 281210). GUYANA: ESSEQUIBO:Kartaba (AMNH 98194); UNKNOWN: ‘‘Dunoon’’(UMMZ 47757–47758); ‘‘Demerara River’’ (UMMZ53900); ‘‘Wismar’’ (UMMZ 76690 [n52], 77504); Kartabo(AMNH 81425, AMNH 21275). PERU: MADRE DEDIOS: ‘‘Cusco Amazonico, 15 km E Puerto Maldonado,200 m’’ (KU 214858). SURINAM: MAROIJNE: Tepoe(UTACV 15772). VENEZUELA: ARAGUA: ParqueNacional Rancho Grande (UMMZ 124243, 124339,AMNH 81423, 98244); BOLIVAR: ‘‘Rio Yuruari, upperbasin, 300 m a.s.l.’’ (AMNH 111075); Santa Elena(AMNH 114769–70); CARABOBO: ‘‘San Esteban,Puerto Cabello’’ (MCZ 51477); DISTRITO FEDERAL:‘‘Laguayra’’ (5La Guaira) (USNM 22531); GUARICO:‘‘Parque Nacional Guatopo, 15 km NW of Altagracia,9u589N, 66u259W, 680 m’’ (USNM 217182).

Dipsas vermiculata.—ECUADOR: MORONA-SAN-TIAGO: Chiguaza (USNM 210973); NAPO: Rıo NapoWatershed (UMMZ 89029, paratype); PASTAZA: ‘‘1 kmW El Puyo’’ (MCZ 14718); ‘‘Rıo Shilcayacu below Puyo’’(USNM 210972).

Dipsas viguieri.—PANAMA: PANAMA: PipelineRoad, Canal Zone (UMMZ 155717); Chagres River camp#2 (MCZ 3476); CANAL ZONE: ‘‘Madden Rorest Road,2.0 mi S. Transisthmus highway’’ (UF 44290); ‘‘MaddenForest’’ (UF 44291).

Geophis anocularis.—MEXICO: OAXACA: SierraMixe (UTA 8535, 14189, 14191, 12294).

Geophis brachycephalus.—COSTA RICA: CAR-TAGO: Turrialba (UTA 44973).

Geophis dubius.—MEXICO: OAXACA: 4.5 km N LaCumbre (UTA 38826); Agua Agria (UTA 51842).

Geophis duellmani.—MEXICO: OAXACA: SierraJuarez (UTA 8433, 14159).

Geophis rhodogaster.—GUATEMALA: GUATE-MALA: Guatemala City (UTA 17694).

Hydromorphus concolor.—COSTA RICA: CAR-TAGO: Turrialba (UTA 44938–44941).

Imantodes cenchoa.—HONDURAS: no other data(UTA 24861, 25041).

Leptodeira annulata.—GUATEMALA: IZABAL: Mu-nicipio Los Amantes (UTA 22810, 37352).

Ninia diademata.—GUATEMALA: QUETZALTE-NANGO: S slope Volcan Santa Marıa, Finca El Farro(UTA 21114, 21128).

Ninia sebae.—GUATEMALA: QUETZALTE-NANGO: S slope Volcan Santa Marıa, Finca El Farro(UTA 21214, 21217, 21227, 21231).

Plesiodipsas perijanensis.—COLOMBIA. SANTAN-DER: ‘‘Vereda Agua Blanca - Parte alta. Kilometro23 vıa Bucaramanaga - Pamplona. Al frente del Centrode Educacion Ambiental ‘El Diviso’’’ Municipio Florida-blanca (UIS 1211, UIS 1228); Vereda Las Amarillas,Municipio Piedecuesta, 6u58910.60N, 73u01917.50W,1400 m (UIS 1242); Vereda Guarumales, Finca ElReposo, Municipio Tona, 1700 m (UIS 1243); VeredaGuarumales, Finca La Plazuela, Municipio Tona, 2100 m(UIS 1244); CESAR: Socorpa Mission, Sierra de Perija,1350 m [this locality is at approximately 9u479N, 73u29W].VENEZUELA. ZULIA: Jamayaujaina, Sierra de Perija,1700 m (MHNLS 655).

Sibon annulatus.—COSTA RICA: CARTAGO: Pa-vones de Turrialba, 600 m; LIMON: ‘‘Tortuguero’’ (UF10282); HEREDIA: ‘‘Rio Frio, Standard Fruit Company,10u209N, 83u539W, 330 ft’’ (UF 30898, 31292); ‘‘Rio Frio,10u209N, 83u539W, 330 ft’’ (UF 31553).

Sibon anthracops.—COLOMBIA: VALLE: vicinity ofCali (UTACV 18704; this specimen was recovered from amilitary aircraft that had recently returned to SouthCarolina from Cali, Colombia. It is not known if the planespent time at a Central American airport before arrivingin Cali. The locality is likely in error because this is aNuclear Central American species that has otherwisenever been found south of Costa Rica.). COSTA RICA:GUANACASTE: Liberia, Santa Rosa National Park(UTACV 4467); Canas (UMMZ 131721 skull). GUATE-MALA: GUATEMALA: Palencia (UTACV 5552); ElProgreso (UTACV 39185); BAJA VERAPAZ: ‘‘51.7 km SPurulha, CA-14’’ (UTACV 5748); ‘‘23.4 rd km NE ElRancho, CA-14’’ (UTACV 5749). UNKNOWN: no data(UF 117875).

Sibon carri.—GUATEMALA: BAJA VERAPAZ:‘‘20.6 km NW El Rancho, on road between El Ranchoand La Cumbre’’ (UTACV 33070); GUASTATOYA:‘‘ca 3.0 km SSW El Rancho (Km 81 on Hwy CA-9),320 m’’ (UTACV 37270); PROGRESO: El Rancho(UTACV 12946); ZACAPA: ‘‘Km 185 on Hwy CA-9, Finca Santa Beatriz, near Gualan, ca 330 m’’ (UTACV26560); ‘‘Gualan, 1.0 km al E de Dona Maria,por carretera al Atlantico’’ (UTACV 44750); ‘‘Gualan,carretera al Atlantico, Aldea Juan de Paz’’ (UTACV45493).

Sibon dimidiatus.—GUATEMALA: IZABAL: ‘‘Sierrade Santa Cruz, E slope Cerro 1019 (next to Aldea LaLibertad), 150 m’’ (UTACV 26314). COSTA RICA:PUNTARENAS: 3.5 mi SW of Rincon, in bushes (UF30212).

Sibon longifrenis.—COSTA RICA: HEREDIA: RioFrio, Standard Fruit Company, in banana packing house(UF 31787); LIMON: Siquirres (UF 77732).

Sibon nebulatus.—COLOMBIA: Cartagena (UF143444). COSTA RICA: HEREDIA: ‘‘3 km. SE PuertoViejo, on road 31054; Rio Frio, Standard Fruit Company’’(UF 30480, 30481, 31014, 31194, 31269, 32341); localityunknown (UMMZ 138818 skull); LIMON: Tortuguero(UF 15669; 10283 (n53), 10284, 10285 (n52), 10512–10514, 11568, 19549); ‘‘2.0 mi N Tortuguero, TortugaLodge’’ (UF 37172, 44305, 40774, 40784); PUNTAR-ENAS: ‘‘N Palmar Sur on Interamerican Hwy’’ (UF44304). ECUADOR: PICHINCHA: ‘‘47 km S SantoDomingo de los Colorados, Centro Cientifico RioPalenque, below station building’’ (UF 68033). GUATE-


MALA: PETEN: ‘‘Peten, Tikal’’ (UF 13847). HON-DURAS: OLANCHO: ‘‘12 km SW Catacamas on road toJuticalpa’’ (UF 44334); UNKNOWN: no other data (UF42970, 87863, 99216, UMMZ 149980 skull). MEXICO:NAYARIT: San Blas (UF 86613); no other data (UF86612); VERACRUZ–LLAVE: ‘‘Hwy. 180 betweenCatemaco and Acayucai 8.5 km S Catemaco’’ (UF44309). PANAMA: COCLE: El Valle (UF 24916);PANAMA: UNKNOWN: El Aquacate (UF 44313).SURINAME: PARAMARIBO: Combe (UF 27051).TOBAGO: UNKNOWN: ‘‘3.7 mi. ENE Scarborough’’(UF 44310). TRINIDAD: UNKNOWN: ‘‘Pointe-A-Pierre, West Indies’’ (UF 16528); Port of Spain (UF44332); ‘‘Port of Spain, St. Ann’s, Fondes Amardes’’ (UF44333). VENEZUELA: ARAGUA: ‘‘Km 24, Maracay-Ocumare de la Costa road, 870 m’’ (KU 167575); ‘‘Km 40,Maracay-Ocumare de la Costa road, 100 m’’ (KU 167577–167578); COJEDES: ‘‘Manrique, Tierra Caliente’’ (UF44311–44312); Mun. Cojedes, Camoruco, Finca laCoromoto (UF 117876); FALCON: Klm 45 Road Ule-Dabajuro (UF 126467–12668). UNKNOWN: no otherdata (UF 44306–44307).

Sibon sanniolus.—MEXICO: QUINTANA ROO:27.9 km NE Felipe Carrillo Puerto (KU 157619 skulland external morphology).

Sibynomorphus lavillai.—BOLIVIA: TARIJA: no oth-er data (UTACV 38080).

Sibynomorphus mikani.—BRAZIL: SAO PAULO:Cotia, Granja Viana (UTACV 37711); Osasco, FazendaRecreio (UTACV 37712); Jundiai (UTACV 37713).

Sibynomorphus neuwiedi.—BRAZIL: PARANA: An-tonina (UTACV 35935); RIO GRANDE DO SUL:Viamao Lombo do Pinheiro (UTACV 43953); SAOPAULO: Taubat (UTACV 37714); Igual (UTACV37715); Mococa (UTACV 37716–17).

Sibynomorphus oneili.—PERU: CAJAMARCA: AbraGelic, 13 km E Celendin, 3080 m (KU 212599, cephalicmusculature, maxilla, and external morphology).

Sibynomorphus turgidus.—BOLIVIA: SANTACRUZ: no other data(UTACV 38049, 38067–68). PARA-GUAY: ‘‘vicinity of Asuncion’’ (UTACV 2585, 5599–600).

Sibynomorphus vagus.—PERU:UNKNOWN: Huan-cabamba (MCZ 17422).

Sibynomorphus ventrimaculatus.—ARGENTINA:MISIONES: Iguazu Falls (FMNH 9259, skull andexternal morphology). BRAZIL: RIO GRANDE DOSUL: Porto Alegre (UTACV 37708, 41154).

Tropidodipsas fasciata.—MEXICO: OAXACA: CerroBaul (UTACV 6215–16), Colonıa Rodulfo Figueroa(UTACV 12538).

Tropidodipsas fischeri.—GUATEMALA: CHIMAL-TENANGO: Finca Chichivac (FMNH 20257, skull andexternal morphology); QUEZALTENANGO: ‘‘betweenSan Martın and Colomba Finca Lorena’’ (UMMZ 155635skull). EL SALVADOR: Hacienda Montecristo, 2200 m(KU 63906, skull and external morphology). MEXICO:OAXACA: Cerro Baul (UTACV 5773, 6221–22, 6637,8785, 12539–40).

Tropidodipsas philippii.—MEXICO: COLIMA:7.3 mi E Colima, Mex Hwy 110 (UTACV 4398).JALISCO: 3.3 mi E Puerto los Mazos (UTACV 7916).

Tropidodipsas sartorii.—MEXICO: CHIAPAS: Soco-nusco, 6 km NE Escuintla, 150 m (UMMZ 155632 skull).QUINTANA ROO: 14.6 km NE Felipe Carrillo Puerto(KU 171701 skull and external morphology). SAN LUISPOTOSI: 6.3 mi E Valle de las Fantasmas on Mex. Hwy.70 (UTACV 8405); 4.0 km S Tamazunchale (UTACV12542); 5.5 km NE Xilitla (UTACV 16146); 3.1 km E jct.Mex. Hwy. 57 and 80, Huizache Junction, (UTACV16155); 4.8 km W El Huizache (UTACV 16156).

APPENDIX 2Matrix of character state assignments used to evaluate the phylogenetic affinity of Plesiodipsas.

Genera

Characters

1 2 3 4 5 6 7 8 9 10 11 12 13

Plesiodipsas 1 0 0 1 0 0 1 0 1 a 0 0 aDipsas and Sibynomorphus 1 0 1 0 1 0 1 0 1 a 1 1 bSibon 0 1 1 0 1 1 1 1 1 b 1 1 ?Tropidodipsas sartorii 0 1 0 0 1 1 1 1 1 b 0 0 ?Ancestor of Dipsadini 0 0 0 0 0 0 0 0 0 ? 0 0 ?Adelphicos 0 0 1 0 0 0 0 0 0 ? 0 ? ?Atractus 0 0 0/1 0 1 0 0 0 0 ? 0/1 0 ?Geophis 0 0 0/1 0 0 0 0 0 0 ? 0 0 ?Ninia 0 0 0 0 0 0 0 0 0 ? ? ? ?Rhadinaea 0 0 0 0 0 0 0 0 0 ? 1 ? ?Imantodes 0 0 0/1 0/1 0 0 0 0 0 ? 0 ? ?Leptodeira 0 0 0 1 0/1 0 0 0 0 ? 0 ? ?Tretanorhinus 0 0 0 1 0 0 0 0 0 ? ? ? ?Xenodontinae 0 0 0/1 0/1 1 0 0 0 0 ? 0/1 ? ?


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Plesiodipsas perijanensis