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589

FIGS.9-12. 9,

10 T r a c h y c r u s u s s t r i a t u l u s

sp.nov.: 9, head and p ronotum; 10, lef t middle t ibia .

11, 12,

carabatermes amazonensis

Howden:

I

dorsum; 12, head and pronotum.

third; surface sculpture similar to head; pronotal edges thin, lacking distinct marginal bead,

laterally with marginal row of seta-bearing punctures, anterior and posterior angles not

indicated. Scutellum about two-thirds as long as wide, basal half tumid on each side of feebly

depressed midline, apical half or less feebly concave; surface with several widely separated,

small punctures, otherwise smooth and shining; sides inwardly arcuate or straight, apex

acute. Elytra Fig. 2 with striae feebly impressed, intervals with elongate-oval reticulations

or polygons, otherwise shining and with scattered, long flying hairs; elytra lacking posterior

tubercles or carinae, posterior declivous portions attenuate, slightly explanate near acutely

rounded apices. Metathoracic wings Fig.

7)

fully developed. Pygidium with v-shaped

median membranous area widest basally, terminating in acute point above apex of pygidium.

Antenna nine-segmented sixth segment often appearing divided making antenna appear

10-segmented),club Fig.

4)

three-segmented, club segments elongate. Mandible thin, sharp

and narrow apically, scarcely visible beyond labrum. Mentum Fig.

3)

flat, broad; apically

truncate or very widely, shallowly emarginate. Maxillary palpus four-segmented, apical

segment enlarged, widest near middle, then tapered to acutely rounded apex. Labial palpus

small, three-segmented, apical segment slender, as long as basal segments combined. Fore

coxae Fig.

3)

narrowly separated, very elongate-conical, bases transverse. Fore femur with

small patch of setae on anterior base adjacent to coxa, row of scattered long setae present

along ventral edge. Fore tibia with apical and one proximal tooth, outer edge with row of

stout setae, setal bases making edge feebly serrate; males with unusually flattened and

hooked apical spur Fig. 5); females with apical spur slender, straight, tip acute. Fore tarsus

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590 THE C N DI N

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with basal and apical segments twice as long as wide, other segments as long as wide or

longer; tarsus attached near apical fourth on ventral surface of tibia. Middle and hind coxae

very narrowly separated; middle and hind tibiae flattened, outer surface with rows of erect

setae, setal bases tuberculate, surface between tubercles finely reticulate or imbricate.

Metasternurn short, length along midline about one-fourth width. Abdomen (of dried

specimens) shrunken, with membranous areas between tergites and sternites (abdomen

seemingly capable of considerable expansion).

Type Species

rachycrusus lescheni

sp.nov.

Remarks

The genus rachycrusus can be distinguished from other New World genera of

Ceratocanthinae by the following combination of characters: clypeal margin scalloped;

surface of head and pronotum with polygonal reticulations and long, erect setae; eytral apices

slightly extended, acutely rounded; outer flattened surface of middle and hind tibiae lacking

distinct carinae, with rows of scattered long, erect setae, each arising from a tuberculate base;

males with fore tibial spur flattened and with a distinct hook on the end (Fig. 5).

The two species here placed in this genus are capable of flexing the head and pronotum

downward, forming an elongate ball as is typical for many Ceratocanthinae.

rachycrusus lescheni sp nov

(Figs. 1-8)

Holotype Male, length 4.9 mm (combined length of head, pronotum, and elytra measured

individually), greatest width 2.0 mm. Clypeal edge with seven notches, each notch with long,

straight seta, each lobe between notches about four times as wide as notch. Edge of each

gena with four feebly indicated setose notches. Pronotum (Fig.

1)

with distinct transverse

depression in posterior median third with distinctly tumid area near posterior margin; lateral

margin on each side evenly, broadly arcuate, anterior and posterior angles not indicated. Each

elytron (Fig. 2) over twice as long as wide; striae present but obscured by transverse lines,

surface thus appearing covered with elongate reticulations; sutural and alternate intervals

with widely separated, long, erect setae (flying hairs); elytron laterally with carinate edge

delimiting narrow epipleuron, otherwise carina(e) lacking. Outer flattened surface of hind

tibia (Fig. 6) with length to width ratio of 7.5:2.2; vague carinate line present on basal half

near inner edge. Male genitalia (Fig. 8) with slightly asymmetrical parameres.

Allotype Female, length 4.6 mm (combined measurements as in male), greatest width

2.1 mm. Differing from male as follows: clypeal edge with nine notches; pronotum with

lateral edges slightly more widely rounded; fore tibial spur slender, straight, unmodified.

Other external characters not differing noticeably from male.

Type Material

Holotype, male, Peru, Dept. Loreto, Campamento San Jacinto 2 18.7SfS,

75 51.77'W, 7 July 1993,175-215 m, Richard Leschen, #42, ex: flt. icpt. trap, Qd 21 (Snow

Entomological Museum, University of Kansas). Allotype, female, same data as holotype

except #45, Qd 20 (Snow Entomological Museum, University of Kansas).

Paratypes, 3 males, 3 females. All same data as holotype except: 2,5.VII.1993, #33

Qd 20; 1,9.VII.1993, #65, Qd 21; 3,11.VI1.1993, #82, #85. Paratypes are in the Gill,

Howden, Snow Entomological Museum, and Canadian Museum of Nature collections.

Remarks

Variation in the small series is negligible. Length varies by about 0.2 mm and

width by 0.1 mm. The position and number of dorsal setae show some variation, but this

seems to be due to abrasion. The size of this species will distinguish it from its congener

described subsequently.

The species is named for Richard Leschen who not only collected the species but

recognized that it represented an undescribed taxon.

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THE CANADIAN

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rachycrusus striatulus sp nov

(Figs. 9, 10)

Holotype

Male, length 4.0 mm (combined measurements of head, pronotum, and elytra

measured individually), greatest width 1.8 mm. Clypeal edge with 10 notches, each with

long, straight seta, resulting scalloping with each lobe about three times as wide as notch.

Edge of each gena with five or six feebly indented setose notches. Pronotum (Fig. 9) with

shallow median depression in posterior half, lateral thirds of pronotum each with shallow

depression midway between broadly rounded margins; lateral margin on each side evenly,

broadly arcuate, anterior and posterior angles not indicated. Each elytron slightly more than

twice as long as wide, striae on disc represented by feebly impressed lines, striae becoming

obsolete laterally and just posterior to basal edge of elytron, intervals medially with scattered

flying hairs and row of obscure reticulations; elytron laterally in basal two-thirds with

rounded ridge above and paralleling epipleural carina; otherwise lacking distinct carinae.

Outer flattened surface of hind tibia (Fig. 10) twice as long as wide, ratio of 2: l; vague

carinate line present on basal half near inner edge. [Genitalia not extracted.]

Allotype

Female, length 3.6 mm (combined measurements), greatest width 1.7 mm. Dif-

fering from male as follows: median posterior pronotal depression smaller, less pronounced;

striae on elytral disc slightly more impressed; fore tibia1 spur slender, straight, unmodified.

Other external characters not differing noticeably from male.

Type M aterial

Holotype, male, Peru, Dept. Loreto, Teniente Lopez, 2 35.66'S, 76 06.92'W,

23 July 1993, 210-240 m, Richard Leschen #191, ex flight intercept trap (Snow Entomo-

logical Museum, University of Kansas). Allotype, female, same data as holotype except

1.5

km

N. Teniente Lopez, 22.VII.1993, #165, Qd 17 (Howden).

Remarks Although T. striatulus is closely related to T. lescheni, T. striatulus can be distin-

guished by its smaller size, shallower median depression of the pronotum, less reticulate

elytra, and distinctly broader middle and hind tibiae.

Relationships

In the paper describing Xenocanthus Howden and Gill (1988a), we listed 20 characters

and their character states (1988a, p. 2075, table 1) that we felt were useful in placing odd

genera in either the Ceratocanthinae or in related subfamilies. Within the Ceratocanthinae

we found that Ceratocanthus White, Germarostes Paulian, Scarabaeinus Silvestri (Howden,

1971), Scarabatermes Howden, and Xenocanthus all shared the following apomorphies

(character numbers are those used in tables 1 and

2

in Howden and Gill 1988a, p. 2075):

5, eye canthus dividing half or more of eye; 7, antenna1 club elongate; 10, prosternum

lacking keels or spines, capable of flexing downward; 12, metastemum short between middle

and hind coxae; 13, anterior tarsal insertion on underside of tibia near apical fourth;

16, M-Cu loop of metathoracic wing absent. Subsequently another unusually modified

genus, Ivieolus Howden and Gill (1988b), was found to share all of the above apomorphies.

Trachycrusus is also apomorphic for characters 5, 7, 10, 12,

13

and 16 (as well as for

characters 1 ,8, and 15). Although these character states indicate that Trachycrusus belongs

in the Ceratocanthinae, they do not reveal any information about relationships within the

subfamily. Table 1 lists some additional characters that help elucidate the relationship of

Trachycrusus to other genera in the Ceratocanthinae. For polarizing these character states,

we have used the hybosorine genera Liparochrus Erichson and Phaeochrous Castelnau as

the outgroup (Howden and Gill 1 988~) .he results are presented in Table 2.

A

number of other characters could be listed, but as far as we can ascertain they would

not improve our assessment of the placement of Trachycrusus. Our analysis indicates that

Trachycrusus is most closely related to Scarabatermes (Figs. 11, 12), sharing five of seven

apomorphies (Table 2). However, it also shares the apomorphic state of flattened middle and

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THE CANAD IAN ENTOMOLOGIST July/August

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TABLE

. Plesiomorphic and apomorphic states of additional characters useful in assessing phylogenetic

relationships among ceratocanthine genera. Supplement to list provided by Howden and Gill

1 9 8 8 ~ ) .

haracter

and state numbers follow the sequence in Howden and Gill

1 9 8 8 ~ )

Character Plesiomorphic

-)

Apomorphic

+)

2 Anterior clypeal edge

22

Anterior pronotal angles

23 Pronotal disc

4 Elytral carinae in addition

to epipleural carina

25 Elytral setae

26 Apex of elytron

27 Middle and hind tibiae

Even Scalloped

Abruptly rounded, acute

Evenly rounded, angle absent

Evenly convex

Uneven or with indentations

Absent Present, either laterally or

apically or both

Short or absent

Long, erect flying hairs)

Rounded Attenuate, slightly reflexed

Round or oval in cross

Flattened

section

hind tibiae characteristic of typical ceratocanthines such as Astaenomoechus Martinez and

Pereira and Ceratocanthus. As a result, Trachycrusus bridges the gap between the highly

modified South American genera and the more typical ceratocanthines.

It should be emphasized that some Old World genera that we have not examined may

actually be more closely related to Trachycrusus than either Scarabatermes or Astaeno-

moechus,

because

Trachycrusus

has several autapomorphies that, if they occur elsewhere,

might change our placement. At present, however, both the wide non-emarginate mentum

and the peculiar anterior tarsal spur of the male are unique to Trachycrusus.

The other reason for our tentative analysis is our conviction that further collecting with

flight interception traps in tropical South America will almost certainly produce many

additional undescribed Ceratocanthinae.

Acknowledgments

We are very much indebted to

R

Leschen and J.S. Ashe, Department of Entomology,

University of Kansas, Lawrence, for furnishing us the specimens used in this study. We also

thank F. GCnier, Canadian Museum of Nature, Ottawa, for his assistance with this project.

The SEM micrographs were done by L.E.C. Ling, Carleton University, and

K

McLachlan-

Hamilton and

T.

MacKechnie assisted with the plates and manuscript. This work has been

supported, in part, by an operating grant to H.F. Howden from the Natural Sciences and

Engineering Research Council of Canada.

TABLE

Distribution of character states listed in Table

1

among selected ceratocanthine

genera. ( + indicates apomorphic condition)

Character state

Genus

2

23 4

25 26 27

Astaenomoechus

Ceratocanthus

Germarostes

Ivieolus

Scarabaeinus

Scarabatermes

Trachycrusus

Xenocanthus

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References

Howden, H.F. 1971. Five unusual genera of New World Scarabaeidae (Coleoptera).The Canadian Entomologist

103: 1463-1471.

1973.

Scarabatermes amazonensis,

anew genus, new species, of termitophilous Scarabaeidae Coleoptera).

The Canadian Entomologist 105: 29-33.

Howden, H.F., and B.D. Gill. 1988a. Xenocanthus, a new genus of inquiline Scarabaeidae from southeastern

Venezuela (Coleoptera). Canadian Journal of Zoology

:

2071-2076.

1988b. A fourth genus of unusually modified Ceratocanthinae (Coleoptera: Scarabaeidae) from South

America.

Canadian Journal of Zoology :

2077-2079.

Paulian,

R

1982. Revision des Ckratocanthides (Coleoptera Scarabaeoidea) d Am6rique du Sud. Mimoires du

Musium national Histoire naturelle, Sirie A Zoologie 24:

110 pp. plates I XVIII.

(Date received: 17 April 1994; date accepted: April 1995)

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