Disparity of Early Cretaceous Lamniformes sharks

Independent Project at the Department of Earth Sciences Självständigt arbete vid Institutionen för geovetenskaper

2015: 7

Disparity of Early Cretaceous Lamniformes Sharks

Disparitet i Lamniformes Hajar från Tidig Krita

Fredrik Söderblom

DEPARTMENT OF EARTH SCIENCES

I N S T I T U T I O N E N F Ö R

G E O V E T E N S K A P E R

Independent Project at the Department of Earth Sciences Självständigt arbete vid Institutionen för geovetenskaper

2015: 7

Disparity of Early Cretaceous Lamniformes Sharks

Disparitet i Lamniformes Hajar från Tidig Krita

Fredrik Söderblom

Copyright © Fredrik Söderblom and the Department of Earth Sciences, Uppsala University Published at Department of Earth Sciences, Uppsala University (www.geo.uu.se), Uppsala, 2015

Sammanfattning Disparitet i Lamniformes Hajar från Tidig Krita Fredrik Söderblom Morfologisk disparitet är ett mått på hur stor utsträckningen av morfologisk variation är. Detta mått räknas ut genom att jämföra landmärken utplacerade på bilder av föremål som ska undersökas. I detta projekt undersöktes den morfologiska dispariteten hos tänder från håbrandsartade hajar (Lamniformes) under tidig krita. Att just deras tänder undersöktes beror på att den större delen av hajars skelett är gjort av brosk vilket lätt bryts ned efter djuret avlidit. Deras tänder är dock gjorda av ben vilket har lättare att bli bevarat som fossil. Utöver detta så kan formen på tänder beskriva djurs födoval och levnadssätt. Gruppens tänder undersöktes därför även för att belysa eventuella förändringar i diet och ekologi under tidig krita. Resultatet av denna analys visar på en expansion av tandform under denna period från långa och smala tänder under Barremium till en större variation under Albium där även mer triangelformade och robusta tänder dyker upp. Detta har tolkats som en adaptiv artbildningsperiod för gruppen då både nya byten (t.ex. teleostfiskar och havs-sköldpaddor) diversifierade och uppkom samtidigt som vissa marina predatorer (ichthyosaurer och plesiosaurer) minskade i antal under denna tidsperiod. Detta ändrade troligen de selektiva trycken på håbrandsartade hajars tandmorfologi samt lämnade ekologiska nischer öppna som dessa kunde anpassa sig till vilket i sin tur ledde till expansioner i morfologisk disparitet, diet och ekologi. Nyckelord: Lamniformes, disparitet, tidig krita, morfologi, morfometri Självständigt arbete i geovetenskap, 1GV029, 15 hp, 2015 Handledare: Nicolàs Campione Biträdande handledare: Benjamin Kear Institutionen för geovetenskaper, Uppsala universitet, Villavägen 16, 752 36 Uppsala (www.geo.uu.se) Hela publikationen finns tillgänglig på www.diva-portal.org

Abstract Disparity of Early Cretaceous Lamniformes sharks Fredrik Söderblom The geological range of lamniform sharks stretches from present day species such as Carcharodon carcharias (great white shark) back to the at the moment oldest undoubted fossil finds during the Early Cretaceous. In this paper a geometric morphometric analysis was performed on images of Early Cretaceous lamniform teeth collected from published literature in order to examine the change in disparity (range of morphological variation within a group) throughout the time period. Due to limited availability of published material and time constraints only the Barremian and Albian ages were investigated. The Barremian exhibited tall and narrow tooth morphologies while the Albian showed a wide range of morphological variation including more robust, wide and sometimes triangular shapes but also displayed further specialization of the tall and narrow forms. This change is likely indicative of a dietary and ecological expansion from only eating for example small fish and soft-bodied creatures to a wide range of prey for the group, including larger and more robust animals such as marine turtles and large bony fish. This in combination with the decline of some marine predators as well as the diversification of possible prey is interpreted as that an adaptive radiation of the Lamniformes could have taken place during the latter half of the Early Cretaceous. Key words: Lamniformes, disparity, Early Cretaceous, morphology, morphometric Independent Project in Earth Science, 1GV029, 15 credits, 2015 Supervisor: Nicolàs Campione Co-Supervisor: Benjamin Kear Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala (www.geo.uu.se) The whole document is available at www.diva-portal.org

Table of contents 1. Introduction 1

2. Materials and methods 2

3. Results 3

4. Discussion 5 4.1 Discussion of the results 5 4.2 Dental adaptations and habitats 6 4.2.1 The Barremian 6

4.2.2 The Albian 8

4.3 On changes in disparity, diversity, diet and feeding strategies 10

5. Conclusions 13

6. Acknowledgements 14

7. References 14 7.1 Printed refereces 14 7.2 Internet references 17

8. Appendix 17

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1. Introduction Chondrichthyes is the name of a group including the clades Holocephali (chimaeras) as well as Elasmobranchii (sharks and rays) (Miller et al., 2003; Hickman et al., 2011). Fossil scales prove chondrichthyans to possibly have existed since the Late Ordovician (Janvier, P., 1996 & Turner, S. in Miller et al., 2003). They are fish with a skeleton made of cartilage, a feature that developed as they evolved out of their ancestors with skeletons made of bone (Hickman et al., 2011). The fact that their teeth are better mineralized than the rest of their skeleton is the reason that teeth are one of the most common kind of fossil found belonging to them since cartilage is less likely to survive the fossilization process (Shimada, 2005, 2007; Whitenack & Gottfried, 2010). Sharks that are a part of them have been determined to have existed during the Early Devonian on the basis of fossil teeth (Miller et al., 2003) and even back to the Lower Siluran on the basis of simple placoid scales (Karatajūté-Talimaa, V., 1973, 1992 in Sansom et al., 1996). The clade Lamniformes is an order of sharks that is present on Earth today and includes the great white shark (Carcharodon carcharias) (Cappetta, 2012). The order’s origin was however during the Early Cretaceous with one of the earliest undoubted fossil finds belonging to the early part of the Late Valanginian (Rees, 2005). Although the possibility of an origin during the Jurassic has also been proposed (Underwood, 2006). The Cretaceous is a time period that spans from 145-66 million years ago (Ma) (Cohen et al., 2015). The period is divided into the Early Cretaceous (145-100.5 Ma) and the Late Cretaceous (100.5-66 Ma) (Cohen et al., 2015). The Early Cretaceous was the focus of this study. It can be further subdivided into the Berriasian (145-139.8 Ma), the Valanginian (139.8-132.9 Ma), the Hauterivian (132.9-129.4 Ma), the Barremian (129.4-125 Ma), the Aptian (125-113 Ma) and the Albian (113-100,5 Ma) (Cohen et al., 2015).

During the beginning of the Early Cretaceous the global climate became more arid than before (Benson & Druckenmiller, 2014) (evidenced in part by clays having an increased proportion of the mineral smectite (Weissert & Channell, 1989; Hallam et al., 1991)), the ocean surface became more oligotrophic (Danelian & Johnson, 2001; Tremolada et al., 2006 in Benson & Druckenmiller, 2014) and temperatures rose to eventually reach a high approximately 100 million years ago (Gould et al., 2001). Radiations of several different organisms took place in the Cretaceous and many of them originated during the Early Cretaceous (Sadava et al., 2011). The first angiosperms (flowering plants) appeared during the Early Cretaceous (Gould et al., 2001; Sadava et al., 2011), triggering a radiation of insects such as butterflies, bees, moths, as well as ants (Gould et al., 2001). The first snakes arose during the Early Cretaceous (Benton, 2005; Sadava et al., 2011). Other organisms such as gymnosperms, teleost fishes, sharks, plesiosaurs, belemnites, ammonites (Gould et al., 2001), dinosaurs (Gould et al., 2001; Sadava et al., 2011), pterosaurs (Gould et al., 2001) (pterodactyloid pterosaurs during the Early Cretaceous (Benson & Druckenmiller, 2014)) and turtles (Early Cretaceous) (Scheyer et al., 2014) would diversify during the Cretaceous. Large predators such as mosasaurs also appeared in the Cretaceous as well as the first true lobsters and crabs (Gould et al., 2001).

With this paper a dataset connected to images of Early Cretaceous Lamniformes shark teeth will be presented (see appendix). A geometric morphometric analysis of the teeth in these images was also performed. The results of this analysis will be presented as diagrams. A morphospace diagram showcasing

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the measure of morphological variation between specimen in a mathematical space and a disparity through time diagram showing the disparity (the range of morphological variation within a group (Briggs & Crowther, 2001)) of lamniform teeth during the different ages of the Early Cretaceous. A t-test was also performed to account for the significance of the sampled specimen in question between the different time bins. The hypothesis being tested is that since a sizeable amount of radiations seem to have taken place at the time investigated in this paper, the results of the analysis might show a high amount disparity and possibly an increase in morphological variation during the aforementioned time period. 2. Materials and methods A total of 146 images of Lamniformes teeth specimen were located using published literature available in both digital and physical formats and compiled into a dataset (see table 1 in appendix). The preferred view in the images was labial (seen from the outside of the mouth), however if this was not available then lingual view (seen from the inside of the mouth) was used. The selection of the images gathered and used was based on availability and unfortunately somewhat restricted by amount of time available to work on this study.

These images were then scanned (if the image was from a physical source) or saved (if the source was digital) as JPEGs. At the same time information about the images such as where it was taken from, which page it was taken from, figure number, which dental unit it was from, what specimen number it had, what order, family, genus and species it was, what view the images was taken in, its relative position in the cranium of the individual, what continent, country, locality and formation it was found in as well as what era, period, epoch and age it belonged to. This information was put together into a dataset in Microsoft excel. The images were then cropped using Adobe Photoshop CC 2014 (Adobe Systems Software Ireland Ltd) and a scale bar was also moved into the newly created image if it was available in the original figure. The teeth were then re-oriented by flipping them in Microsoft Paint so the apex of the crown (see figure 7 in appendix for explanation of tooth component locations) in every image was oriented either straight up if the tooth crown was straight or up and to the left if the tooth crown was inclined. A tps file was created by inputting the folder containing only the images of complete specimens (85 in total (see table 2 in appendix) of which seven were of Barremian age and 78 were of Albian age) in the open-source program tpsUtil (version 1.60) created by F. James Rohlf (Rohlf, 2015). Afterward in the program tpsDIG2 (version 2.18) created by F. James Rohlf (Rohlf, 2015) the images of the tps file were placed on a Euclidian coordinate grid. tpsDIG2 was then used to digitize the images by placing semilandmarks along the edge of the crown going from the left side of the crown to the right (see figure 7 in appendix). The semilandmarks made up a curve and were then all resampled to 74 points along the curve with equal length between each other.

In notepad, the semilandmarks in the tps file were changed into homologous landmarks. This file was then entered into tpsUtil where it was used to create a sliders file in which all landmarks were linked and marked to slide except for the first and last ones. The tps- and sliders files as well as the dataset (table 2 in appendix) were then imported into the statistical programming program RStudio (RStudio) using the package geomorph (a package that can analyze the shape of

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both two-dimensional and three-dimensional landmark data) (Adams, D. C. & Otarola-Castillo, E., 2013; Adams et al., 2015) where they then were used to run a generalized procrustes analysis (GPA) (using the tps- and sliders files all the specimens were moved to the same point in mathematical space, scaled to approximately the same size and rotated in an as close as possible same direction so that distances between the same landmark in different specimen could be measured) (Adams et al., 2015)) and a principal component analysis (PCA) (plots the specimens aligned in the GPA along principal axes (Adams et al., 2015)) that generated a morphospace diagram of the sample (figure 1).

The samples (dots) were then partitioned into time bins corresponding to their geological age using the imported dataset and the RStudio which () command. The dots on the edges of the corresponding time bins were then linked by lines using a function called minimum convex hulls (Campione, N.) and were colored by using the RStudio command points (). Images of the mean of principal component 1 (PC1) and principal component 2 (PC2) minimum and maximum values were generated in RStudio. These were then added to their respective positions in the morphospace diagram by using the program Inkscape (Inkscape). The results from the PCA were then used with the disparity () command from the RStudio package geiger (Harmon et al., 2008) to calculate the disparity for the time bins in question and then a diagram of the disparity through time was plotted. A t-test was also performed on the principal component scores obtained from the PCA in RStudio to test for statistical significance in the sample that was analyzed and the mean of the two ages. 3. Results The results of the analyses are presented below and include the morphospace diagram (figure 1), disparity through time diagram (figure 2) and the results of the t-test. The morphospace in figure 1 does not have any units since variables such as size and angle were removed during the analysis. The differences between landmarks were measured using the Euclidian coordinate grid the images were placed upon. Principal component 1 (PC1) (figure 1) represents the greatest morphological difference of one and the same landmark between all specimen in the analysis. Principal component 2 (PC2) (figure 1) represents the second to greatest morphological difference in another landmark between all specimen used in the analysis.

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Figure 1. Morphospace diagram showing the extent of morphological variation during the ages included in this sample. Samples of Barremian age are shown as red and samples of Albian age are shown as blue. The images on the sides of the diagram show minimum and maximum extremes of the samples’ shape along that particular principal component axis. Principal component axis 1 shows the height and width change in morphology inside the morphospace diagram from narrow and tall (left side) to low and wide (right side). Principal component axis 2 shows the degree to which the cusplets are present where the top part of the figure has large cusplets and the bottom of the figure has none. Furthermore the width of the base of the crown increases in size from the top left toward the bottom right of the morphospace diagram.

Figure 2. Diagram showing the disparity (range of morphological variation within a group) (y axis) through time (x axis) of the sampled specimens. Specimens from other stages were not included in the analysis and are therefore not shown in this diagram.

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In the T-test between the mean of the Barremian specimen (calculated to be -0.14433504 on the principal component 1 axis (figure 1)) and the mean of the Albian specimen (calculated to be 0.01295314 on the principal component 1 axis (figure 1)) a p-value = 0.0307 was obtained. 4. Discussion 4.1 Discussion of the results The results of the morphospace diagram (figure 1) show an increase in disparity as does the disparity through time diagram (figure 2). However three things are worth taking note of. The first problem with these results is that the Aptian, the age which should be placed in between the Barremian and the Albian is missing. This leads to a problem since the statistical significance of the samples reflecting reality cannot be properly ascertained in the detail that would be desirable. In other words, an increase of disparity can be seen in both figure 1 and figure 2 but since there is no accounting for the disparity during the time that is missing (the Aptian), there is no knowing for sure whether there was an increase, decrease or no change in disparity of lamniform teeth from the Barremian to the Aptian or from the Aptian to the Albian. Although what can be seen in both figure 1 and 2 is that an overall increase in disparity of lamniform teeth from the Barremian to the Albian seems to have taken place. So at least in the Albian lamniforms seems to have had a wider range of morphological variation than in the Barremian. The second thing that is noteworthy is that since the Barremian only had seven specimens attributed to it in the analysis it is possible (and also quite likely) that this does not closely enough represent the true extent of Barremian lamniform tooth morphology (and would therefore not show if the true disparity was initially high or not as was hypothesized). There is also the possibility of a sampling bias considering the small amount of Barremian specimen and this would affect the interpretation of the results where it could look like there was a greater expansion in the range of morphology than there actually was during the time from the Barremian to the Albian. All the Barremian samples used in the analysis were of the same family (Eoptolamnidae) and consisted of only three species and genera (Eoptolamna eccentrolopha, Leptostyrax stychi sp. nov. and Protolamna sarstedtensis sp. nov.) (table 2 in appendix). In the complete dataset (table 1 in appendix) 22 specimens are of Barremian age. 19 of these belong to the family Eoptolamnidae. The three remaining Barremian specimen were not assigned to a particular family in the published literature they were taken from. However tooth morphology can vary on the level of genera/species to different degrees and even vary in a single individual’s mouth (heterodonty) depending on not only its belonging in a certain genera or species but also changes such as those during ontogeny (changes taking place when an individual grows up) and sexual dimorphism (gender differentiated traits) (Cappetta, 2012). The diet of a shark can also be influenced by the tooth morphology it possesses since this determines what prey it will be able to catch and consume (Cappetta, 2012).

Other than the Eoptolamnidae families like Cretoxyrhinidae and Odontaspidae were also present during the Barremian (Underwood, 2006). Although this is the case, it is possible that these families either could have possessed a similar dental morphology, adapted to a similar diet or a completely different morphology adapted for other kinds of prey. Measured disparity is more affected by

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the addition of new specimen or removal of existing specimen at the edges of that time bin’s area since this would change the appearance of the time bin in morphospace to a greater degree than adding or removing a specimen in the middle of the time bin’s area (Foote, 1993). Also, the larger the size of a group within a time bin in morphospace the more it affects disparity (Foote, 1993). In other words, if a group is large and very peripheral in morphospace it affects that time bin to a much greater extent than a small and centralized group within time bin.This would mean that if Barremian specimen with quite different morphologies than the ones in the morphospace diagram were added this would likely expand the Barremian time bin’s area. However if the new specimen added were very similar morphologically to the ones already in the time bin this would likely not expand the time bin or increase disparity to any larger degree.

In other words, this does not completely invalidate the Barremian time bin shown in figure 1 although it should be expanded upon with more specimens to more correctly represent the true extent of lamniform tooth morphology during this particular age. The Albian seems to be quite well sampled and is showing a quite varied morphology as seen in both figures 1 and 2. It should be noted though that 25 of the 78 specimens from the Albin time bin in the analysis were defined by the authors of the paper they were taken from as belonging to either the latest Late Albian or earliest Early Cenomanian (Siverson et al., 2013) and therefore should be considered as a possible source of error in the analysis performed in this paper since they might belong to an age not investigated here. Both the Barremian and Albin time bins will be discussed below.

Lastly, the results of the t-test showed a p-value of 0.0307 which means in turn that the sample is significant at the 5% level (Olsson et al., 2005). Furthermore the t-test also showed the mean of the Barremian specimens to be located at -0.14433504 on PC1 and the mean of the Albian at 0.01295314 on PC1. If compared to figure 1 this seems to be correctly assessed and would likely serve as evidence for a shift in average morphology of the two time bins. The Barremian time bin’s PC1 average on the negative (left) side of the PC1 axis suggests a tall and narrow morphology, most likely more adapted to catching and consuming soft-bodied animals or smaller fish. The Albian time bin’s PC1 average is placed in a more central location along the PC1 axis, which would indicate a more varied (and wide) range of morphologies (as also evidenced by the negative and positive extremes of specimen in the Albian time bin) including the narrow and tall morphology already present in the Barremian but also more low and wide teeth useful for processing more robust prey. Descriptions of dentition types as well as their implications concerning diet, examples of feeding strategy and some possible driving forces behind the dentition morphology shifts of lamniforms during the Early Cretaceous will be discussed below (subheadings 4.2 and 4.3). 4.2 Dental adaptations and habitats

4.2.1 The Barremian The disparity of the Barremian specimens shown in figure 1 seem to indicate a tooth morphology with a quite straight (except for one of the specimen which seems to have its main cusp bent slightly more than the others toward the rear of its mouth), tall, narrow and pointed main cusp and with somewhat medium sized cusplets (smaller thorn-like structures next to the main cusp (see figure 7 in appendix)). The

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teeth seem to be either of the clutching type or tearing type dentitions mentioned by Cappetta (2012). Clutching type dentition (figure 3) generally involves quite small teeth set in rows with a smooth/straight or either lingually or labially bent crown (Cappetta, 2012). Clutching dentition often includes one or more pairs of cusplets and is usually an adaptation that is used by present day elasmobranchs to puncture and hold on to (aided by the cusplets) softer prey such as fish and cephalopods that move very quickly in open water (Cappetta, 2012). Ramsay & Wilga (2007) did however show that the recent shark Chiloscyllium plagiosum (white-spotted bamboo shark) is physically capable durophagy (eating hard-shelled prey, e.g. crustaceans and hard-shelled mollusks) by rotating its teeth lingually (toward the inside of the mouth) through the use of dental ligaments and by doing so changing the function of its clutching dentition into that of a crushing dentition. If this function existed in Early Cretaceous lamniform sharks though is unknown. Furthermore, Cappetta (2012) also mentions that this type of dentition is common in sharks benthic and demersal zones (living on respectively a bit above the bottom of the sea) and also in the neritic zone (above the continental shelf).

Figure 3. Simplified example of the range of clutching type dentition present in this paper. Tearing type dentition (figure 4) usually has one to several pairs of lateral cusplets (though in some genera they are missing) and more noticeable cutting edges along the side of the crown (Cappetta, 2012). Some sharks with tearing type dentition even acquired a cutting function during the Early Cretaceous due to increased sharpness of the crown’s edges (Cappetta, 2012). Sharks with this dentition possess the ability to bite through bone (Ramsay & Wilga, 2007) and are therefore more likely to eat more robust prey than the clutching dentition mentioned above. The habitats of extant sharks with tearing type dentition include bathyal (deep waters), littoral (near shore), epipelagic (far up in the open ocean outside the continental shelf) and pelagic (open ocean) environments (Cappetta, 2012).

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Figure 4. Simplified example of the range of tearing type dentition present in this paper. Tearing type dentition may also include more noticeable cusplets.

4.2.2 The Albian Figure 1 seems to indicate that during the Albian stage, morphology was quite varied within the Lamniformes order. The Albian time bin seems to have expanded a lot in the positive direction and only a little in the negative direction on PC1. It also expanded a lot in the negative direction but only somewhat in the positive direction on PC2. The order seems to have increased its dental disparity in the Albian compared to the Barremian by (except for the morphologies present then) either (1) shortening the main cusp (and either keeping it straight or bending it), widening the crown base and elongating the cusplets (specializing more in clutching dentition), (2) elongating its main cusp as well as decreasing the size of its cusplets (and in some cases widening the crown base) or (3) bending the apex of its main cusp toward the rear to varying degrees, widening the crown base and losing its cusplets (figure 7 in appendix and figure 1). This wide a range of morphological expansion in approximately 12-25.5 million years would indicate some sort of adaptive radiation due to a change in selective pressures (more on this below in subheading 4.3). Again following the terminology used by Cappetta (2012), the tearing- and clutching type dentitions mentioned previously (see 4.2.1 The Barremian) also seem to be present in this Albian (see figure 1) and seem to have somewhat further specialized. Additionally, types such as sensu stricto cutting dentition and cutting-clutching dentition are also encompassed by the Albian time bin in figure 1. Both of these are subtypes of the cutting type dentition (Cappetta, 2012). Sensu stricto cutting dentition (figure 5) is characterized by labio-lingual flattening and also a general widening (Cappetta, 2012). Because of this labio-lingual flattening and the fact that this dentition type’s crown often is bent backwards (though sometimes it is straight) and linked together (complete linkage is not always present) into a continuous row of teeth creates something akin to a blade (Cappetta, 2012). Teeth with this kind of dentition may also have serrated edges (Cappetta, 2012). Sensu stricto cutting dentition is able to cut the flesh of prey into pieces as well as chew through bone by acting as a pair of scissors (Ramsay & Wilga, 2007) allowing it

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to eat very robust and large prey. Sharks with sensu stricto cutting dentition can often be found in bathyal, pelagic and neritic areas of the sea (Cappetta, 2012).

Figure 5. Simplified example of the range of sensu stricto cutting type dentition present in this paper. The cutting-clutching subtype dentition (figure 6) exhibits a quite strong differentiation between the upper and lower jaw of the individual (Cappetta, 2012). One jaw has high and narrow cusps (most often in (but not restricted to) the anterolateral and anterior teeth) (Cappetta, 2012). The other jaw can have wide teeth that are flattened labio-lingually (Cappetta, 2012). Like sensu stricto cutting dentition, cutting-clutching dentition can also be used to cut through bone and flesh of more robust creatures. Cutting-clutching dentition can be found in sharks living in bathyal, epipelagic and littoral environments (Cappetta, 2012). It should be noted that Ramsay & Wilga (2007) do mention in their paper that cutting dentition seems to be present in sharks that nourish themselves by consuming fish, mammals and soft-bodied invertebrates.

Figure 6. Simplified example of the range of cutting-clutching type dentition present in this paper. Left side shows the range of cutting teeth. Right side shows the range of clutching teeth (most often present in the anterior and anterolateral teeth of one jaw).

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4.3 On changes in disparity, diversity, diet and feeding strategies The hypothesis posed in the introduction of this study would seem to fit quite well with the results of the analyses that were conducted. However since as mentioned earlier only the latter part of the Early Cretaceous was covered by this study, the Barremian stage was represented only by seven specimen and there was a hiatus of specimen during the Aptian in this study the correctness by which the results actually depict the change in disparity from the Barremian to the Albian is not quite optimal. Expanding upon the dataset and running additional analyses would be advisable and would have been done if not due to time constraints. Nevertheless the Albian time bin had a decent amount of specimens attributed to it and the results during that particular stage should be viewed as a quite correct representation of the disparity calculated for that interval of time. If one would assume that the Barremian time bin is somewhat representative of the actual disparity of that stage and then compared it to the Albian then the increase in morphological variation would certainly support the sizeable radiations mentioned in the introduction of this paper. Since the Lamniformes seemed to expand into cutting dentition (except for the tearing and clutching dentitions present in both the Barremian and the Albian) capable of biting through bone and flesh of more robust animals than small fish or for that matter soft invertebrates there would likely have been some event(s) that triggered this push toward a dentition of wider and more sturdy blade-like teeth.

By the Early Cretaceous teleost fishes had already appeared long ago however they diversified during this time (Gould et al., 2001; Benton, 2005). The elopomorphs (clade including eels and their relatives) and clupeomorphs (clade including extant anchovy and herring) arose in the Early Cretaceous (Benton, 2005). It is worthy to mention that during the Early Cretaceous the ichthyosaurs (superficially dolphin-like marine reptiles) that preyed on fish and cephalopods (Gould et al., 2001) throughout the majority of the Mesozoic had started to decline (Gould et al., 2001; Maxwell & Kear, 2010) and would eventually go extinct a time after the end of the Early Cretaceous (the latest finds are from the Cenomanian, the first age of the Late Cretaceous) (Maxwell & Kear, 2010). It was toward the end of the Early Cretaceous that the up to 4.2 meter long predatory fish Xiphanctinus (Benton, 2005) made its appearance (Gould et al., 2001). Xiphactinus fossil have been found with 1.6 meter long prey in its stomach (Benton, 2005). This increase in fish taxa (and in some cases size) might have been brought upon by the decline and extinction of the ichthyosaurs. Their disappearance might have left an open role in Cretaceous ecosystems that would be filled by Xiphactinus and other fish (possibly including some sharks).

Although Xiphactinus might seem large, some species of shark from a family called the Cretoxyrhinidae (one of the lamniform families included in the analysis) could reach a size of six meters long, weigh an approximate of 1.5 tons (Gould et al., 2001) and were equipped with either tearing (Benton, 2005) or cutting dentition (Shimada & Hooks, 2004; Siverson et al., 2013). That the cretoxyrhinid sharks have preyed upon Xiphactinus is supported by the work on Late Cretaceous Cretoxyrhina mantelli from the Niobrara Chalk (Kansas) done by Shimada (1997) where a well preserved fossilized skeleton of C. mantelli was found with the remains of a Xiphactinus audax located posterior to its head. Even plesiosaurs are suggested to possibly have been eaten by Cretoxyrhina from the discovery of what could be

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plesiosaur gastroliths (stones ingested by animals to help break down food often only found in marine low energy sediments in association to plesiosaur fossils) along with Cretoxyrhina remains (Shimada, 1997). However no plesiosaur remains were found associated with the gastroliths.

Shimada (1997) also mentions attacks on mosasaurs by cretoxyrhinid sharks where one of the mosasaurs show evidence of an infection and subsequent healing around an embedded cretoxyrhinid tooth. This was interpreted as evidence of the cretoxyrhinid shark employing an active feeding strategy (as opposed to scavenging a carcass). Siverson (1992 in Schwimmer et al., 1997) hypothesized that C. mantelli could have fed on sea turtles but the only evidence for this was body size and dental morphology. This idea was later confirmed by Shimada & Hooks (2004) through what was determined to be C. mantelli teeth embedded into an individual of the Late Cretaceous protostegid turtle species Protostega gigas, a species with a carapace (upper part of a turtle’s shell) that could reach lengths of more than two meters. The Protostegidae were a turtle family with a geological range from the Albian (last age of the Early Cretaceous) to the Late Campanian (Late Cretaceous) (Shimada & Hooks, 2004). They were part of the turtle superfamily Chelonioidea that appeared as turtles diversified during the late Early Cretaceous (Scheyer et al., 2014) and unlike many of their more ancient relatives the chelonioids were more adapted to open marine environments (Scheyer et al., 2014). The appearance of these new open marine turtles could have changed the selective pressures on lamniform tooth morphology from the more narrow clutching type (often found in neritic or benthic conditions suitable for catching smaller fish and soft-bodied prey) or tearing type dentitions present in the Barremian time bin toward the more robust and wide tearing type or cutting type (found in both pelagic, neritic and bathyal areas) dentitions appearing in the Albian time bin.

While C. mantelli was of a species and time not investigated in this paper, there is the possibility that the cretoxyrhinids (or for that matter other lamniforms) investigated in this paper could have inhabited a similar ecological role as apex predator (or at least high trophic level predator) of some Early Cretaceous ecosystems. This might be somewhat supported by Schwimmer et al. (1997) stating that recent and fossil shark dentition belonging to sharks of the superorder Galeomorpha (including the order Lamniformes) has been very similar since the Early Cretaceous and therefore a similar feeding behavior can be assumed. Except for this Schwimmer et al. (1997) also mention that predatory behavior has always been common in sharks of large size. Teeth belonging to one of the cretoxyrhinids used in the analysis of this paper were of the species Cretoxyrhina vraconensis. This species has been estimated to have reached a length four meters as an adult (Siverson et al., 2013). As a juvenile its anterior teeth were narrow and well adapted for catching cephalopods, bony fish and small elasmobranchs (Siverson et al., 2013). Through ontogenic changes the adult individuals would instead have a more triangular and wide cutting dentition, feeding upon larger prey (Siverson et al., 2013). The size and dentition of C. vraconensis would seem to indicate an ecological role somewhat similar to that of C. mantelli. However, the C. vraconensis teeth used in the analysis were described by Siverson et al. (2013) as being from a top of the food chain predator in a coastal marine environment where large marine reptiles have not been found. This would not preclude the possibility of C. vraconensis living in open marine environments though (however this is just speculation). As mentioned earlier, both sharks with tearing type dentition as well as cutting type dentition can be found in open marine (pelagic) settings (Cappetta, 2012).

12

The genus Squalicorax is also one of the genera included in the analysis performed in this paper. This genus ranges from the Albian (latest age of the Early Cretaceous) to the Maastrichtian (latest age of the Late Cretaceous) and possesses cutting type dentition (Schwimmer et al., 1997). It has been suggested and discussed at length by Schwimmer et al. (1997) that members of the genus used this cutting dentition primarily for scavenging on carcasses from animals such as mosasaurs, plesiosaurs, marine turtles and teleost fishes (as well as occasionally some terrestrial vertebrates that had died and were transported by water out into the ocean). Many of these organisms are believed to have been larger than Squalicorax. Therefore it is believed that they were likely deceased when being fed upon. Schwimmer et al. (1997) mentioned that this might not necessarily indicate a feeding strategy of obligate scavenging but seemed to indicate that it was most likely the primary means used to obtain sustenance by the members of the genus. This use of cutting dentition by Squalicorax shows that just because the dentition could be used to actively hunt and consume large/robust prey (as for example it was likely used by members of the Cretoxyrhinidae), it doesn’t mean that active hunting necessarily was the means used by every wielder of the dentition to obtain food.

Another example of scavenging (or possibly actively attacking prey) is described by Shimada et al. (2010) where teeth (most similarly described as the cutting-clutching dentition in this paper) from six to seven individuals (1.5 to 4.2 meters long) of Late Cretaceous Cretalamna (also known as Cretolamna) appendiculata (an Albian specimen of Cretolamna sp. was used in the analysis of this paper (table 2 in appendix) and seems to have similar dentition to the teeth of Cretalamna appendiculata described by Shimada et al. (2010) which means a similar diet could be inferred) were found both next to and imbedded into a 6.4 to 9.2 meter long individual of the plesiosaur species Futabasaurus suzukii. Plesiosaurs have been shown to have declined in morphological disparity from a high in the middle of the Jurassic (pliosauroid plesiosaur decline in the Late Jurassic) to a low in the early part of the Early Cretaceous (Berriasian-Barremian) (seemlingly substantial cryptoclidid plesiosauroid disparity loss around the Jurassic-Cretaceous boundary) (Benson & Druckenmiller, 2014). Part of them thereafter increased their range of morphological variation (Elasmosauridae, Leptocleididae and Polycotylidae of the Plesiosauroidea), elevating plesiosaur disparity once again toward a high level in the late Early Cretaceous (Aptian-Albian) (Benson & Druckenmiller, 2014) suggesting that they too radiated during the (late) Early Cretaceous. The decline and subsequent radiation of these animals could have acted as another trigger for the radiation and increase in tooth morphology diversity of Lamniformes (as well as possibly bodysize?) by leaving open ecological roles available to adapt into and thereafter giving lamniform sharks additional prey to feed on in the form of smaller sized species of plesiosaurs or young/old, diseased and deceased individuals of large plesiosaur species. The fossil remains of the plesiosauroid described by Shimada et al. (2010) showed no evidence of healing though so it is believed that the biting likely took place after the death of the animal. Another idea mentioned by Shimada et al. (2010) is that the sharks attacked the plesiosaur with a fatal outcome. However the definite cause of the plesiosaur’s death was not established.

Lastly the diversity of lamniform genera (which can possibly but does not necessarily have to be related to changes in morphological variation and dentition types) can also be mentioned through which genera were present during the time analyzed in this paper (Barremian-Albian). During the Barremian at least four lamniform genera seem to have been present (Hispidaspis, Protolamna (Cappetta,

13

2012), Leptostyrax (Schmitz et al., 2010), Eoptolamna (Kriwet et al., 2008)). The Aptian contains at least eight genera (Anomotodon, Scapanorhynchus, Hispidaspis, Paraisurus, Protolamna, Eostriatolamna (Cappetta, 2012), Leptostyrax (Schmitz et al., 2010), Johnlongia (Shimada, 2007)). The Albian seems to be where lamniform genera of the late Early Cretaceous were the most abundant in numbers with 20 genera present (Anomotodon, Scarpanorhynchus, Hispidaspis, Johnlongia, Cardabiodon, Pseudoisurus, Acrolamna, Archaeolamna, Cretoxyrhina, Paraisurus, Leptostyrax, Protolamna, Pseudoscarpanorhyncus, Squalicorax, Cretodus, Dwardius, Eostriatolamna (Cappetta, 2012), Priscusurus (Kriwet, 2006; Cappetta, 2012), Carcharias (Siverson, 1997; Everhart, 2009), Cretolamna (Siverson, 1997; Cappetta, 2012)). There seems to be an increase in genera from the Barremian to the Aptian and then also an increase from the Aptian to the Albian. Although it is possible that these increases could also be driven by the lack of study on shark fossils from pre-Albian Cretaceous rocks (though especially earliest Cretaceous rocks) (Underwood, 2006) and the Barremian and Aptian therefore not having been represented fully. If it would be assumed however that the Barremian and Aptian had been examined well enough, this increase in genera by itself does not mean that the range of morphological variation (disparity) increased. This would only tell the change in number of genera through time and does not tell if there was an overall varied or very similar morphology present throughout the group during the Barremian to the Albian (and therefore does not say anything about the ecology of these sharks either). In other words, high diversity in genera does not have to mean high disparity. When compared to the morphospace diagram in figure 1 and disparity through time diagram in figure 2 though the diversity and the disparity both seem to indicate a time of adaptive radiation for the Lamniformes order that took place sometime during the (late?) Early Cretaceous (possibly in the Aptian and/or Albian). 5. Conclusions Following the pattern of many other organisms during the Early Cretaceous the Lamniformes order of sharks likely radiated in an adaptive manner as well. Although the range of their morphological variation early on during this time could not be confidently assessed, their disparity did increase toward the end of the Early Cretaceous, with a radiation possibly having taken place during the Aptian and/or Albian. The combined action of large marine predator decline (such as ichthyosaurs and plesiosaurs), subsequent open ecological niches and radiation of prey (e.g. open marine turtles, teleost fishes) likely spurred on selective pressures which changed the tooth morphology of lamniforms. The tall and narrow clutching- or tearing type dentitions during the Barremian shifted toward a very varied morphology including clutching-, tearing-, sensu stricto cutting- and cutting-clutching type dentitions during the Albian. Except for the further specialization of the tearing- and clutching dentitions, the wide and robust cutting type dentitions present in the Albian seem to show an expansion in diet from e.g. small fish and soft-bodied animals in the Barremian to a diet of larger animals by the Albian (e.g. large fish, open marine turtles, possibly plesiosaurs). The feeding strategy used by lamniforms with this dentition to obtain their sustenance came likely both in the form of active predation but also through scavenging carcasses. Further investigations into lamniform disparity changes during the Early Cretaceous would require more material, most desireably from all ages of the Early Cretaceous to be analyzed in a geometric morphometric analysis. However this in

14

turn might require further field work to be carried out in order to obtain more specimens. This would be particularly advicable for pre-Albian stages (and especially the oldest stages) of the Early Cretaceous since these appear to have few lamniform specimens attributed to them in comparison to the late Early Cretaceous (in particular the Albian). Geometrical morphometric analyses should also be carried out on other organisms present during this time period to search for patterns in disparity through time, especially regarding to marine organisms. It might serve as a clue for the reason of the disparity pattern observed in the Lamniformes in this paper. When done, these might then be compared to research concerning changes in climate and environment during this time as well as provide a reason and a more complete picture of the ecomorphological changes that took place during the Early Cretaceous. 6. Acknowledgements I would like to thank my supervisor Nicolás Campione for the guidance he has provided throughout this project. I would also like to thank my co-supervisor Benjamin Kear for making the necessary introductions. Additionally I would like to thank Mohammed Bazzi for additional guidance given concerning methodology and image design. 7. References 7.1 Printed refereces Adams, D. C. & Otarola-Castillo, E., 2013, geomorph: an R package for the collection

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Scheyer, T. M., Danilov, I. G., Sukhanov, V. B. & Syromyatnikova, E. V., 2014, The shell bone histology of fossil and extant marine turtles revisited: Marine Turtle Shell Bone Histology, Biological Journal of the Linnean Society, 112(4), pp 701–718

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8. Appendix

Figure 7. Schematic image explaining the locations of components in a shark tooth as well as placement of semilandmarks in this paper.

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Table 1. Complete dataset of the 146 Early Cretaceous Lamniformes tooth specimen collected. All data was collected and entered into the dataset as found in the published material it was collected from. If a piece of information was unspecified in the litterature which it came from then information was assumed when possible, this was marked with an asterisk (*). Every row number represents one specimen each. Row nr. Source Page Image.Label Specimen Dental.Unit

1 Cappetta 2012 232 Figure 214A UM KOB 28 lower*

2 Cappetta 2012 232 Figure 214D UM KOB 29 lower*

3 Cappetta 2012 232 Figure 214F UM KOB 30 lower*

4 Cappetta 2012 238 Figure 218A UM AUB 1 lower*

5 Cappetta 2012 239 Figure 219A UM LTX 1 lower*

6 Cappetta 2012 239 Figure 219D UM LTX 2 lower*

7 Cappetta 2012 239 Figure 219F UM ROK 1 lower

8 Cappetta 2012 240 Figure 220C UM TUI 35 lower

9 Cappetta 2012 240 Figure 220D UM TUI 37 lower

10 Cappetta 2012 240 Figure 220F UM TUI 36 lower





15 Cappetta 2012 255 Figure 233B UM KOB 4 lower*

16 Cappetta 2012 255 Figure 233E UM KOB 5 lower

17 Cappetta 2012 255 Figure 233F UM KOB 6 upper

18 Cappetta 2012 255 Figure 233H UM KOB 7 upper

19 Cappetta 2012 255 Figure 233I UM KOB 8 lower

20 Cappetta 2012 257 Figure 235A UM STO 1 lower*

21 Cappetta 2012 257 Figure 235C UM STO 2 lower*

22 Cappetta 2012 257 Figure 235F UM STO 3 lower*

23 Cappetta 2012 257 Figure 235I UM KOB 31 lower*

24 Cappetta 2012 257 Figure 235K UM KOB 32 lower*

25 Cappetta 2012 261 Figure 240A UM PER 1 lower*

26 Cappetta 2012 261 Figure 240D UM PER 2 lower*

27 Rees 2005 215 Figure 2A ZPAL P.10/8 lower*

28 Rees 2005 215 Figure 2E ZPAL P.10/10 lower*

29 Rees 2005 215 Figure 2F ZPAL P.10/9 lower*

30 Kriwet et al. 2008 282 Figure 2A MPZ 2005-4 lower*

31 Kriwet et al. 2008 282 Figure 2E MPZ 2005-5 lower*

32 Kriwet et al. 2008 282 Figure 2H MPZ 2005-6 lower*

33 Kriwet et al. 2008 282 Figure 2K MPZ 2005-7 lower*

34 Kriwet et al. 2008 282 Figure 2O MPZ 2005-8 lower*

35 Kriwet et al. 2008 282 Figure 2S MPZ 2005-9 lower*

36 Kriwet et al. 2008 282 Figure 2W MPZ 2005-10 lower*

37 Kriwet et al. 2008 283 Figure 3A MPZ 2005-11 lower*

38 Kriwet et al. 2008 283 Figure 3B MPZ 2005-12 lower*

39 Kriwet et al. 2008 283 Figure 3C MPZ 2005-13 lower*

40 Kriwet et al. 2008 283 Figure 3D MPZ 2005-14 lower*

19

41 Kriwet et al. 2008 283 Figure 3F MPZ 2005-15 lower*

42 Kriwet et al. 2008 283 Figure 3G MPZ 2005-16 upper*

43 Everhart 2009 204 Figure 3D FHSM VP-17304 lower*

44 Smart 2007 377 Figure 2A NHM P 66356 lower

45 Smart 2007 377 Figure 2C NHM P 66357 lower

46 Smart 2007 377 Figure 2E NHM P 66358 lower

47 Smart 2007 378 Figure 3A NHM P 66359 upper

48 Smart 2007 378 Figure 3C NHM P 66360 upper

49 Smart 2007 378 Figure 3E NHM P 66361 upper

50 Siverson 2007 et al. 943 Text-fig. 3A SMU 76283 lower*

51 Siverson 2007 et al. 943 Text-fig. 3C SMU 76282 lower*

52 Siverson 2007 et al. 943 Text-fig. 3F SMU 76284 lower*

53 Siverson 2007 et al. 943 Text-fig. 3G SMU 76285 lower*

54 Siverson 2007 et al. 943 Text-fig. 3J SMU 76286 lower*

55 Siverson 2007 et al. 943 Text-fig. 3L SMU 76287 lower*

56 Siverson 2007 et al. 943 Text-fig. 3N SMU 76288 lower*

57 Siverson 2007 et al. 943 Text-fig. 3P SMU 76289 lower*


59 Siverson 2007 et al. 947 Plate 1, figure 1 SMU 76313 lower*













72 Kriwet 2006 540 Figure 2A BMNH P.36287 lower

73 Kriwet 2006 540 Figure 2B BMNH P.36288 lower*

74 Kriwet 2006 540 Figure 3A BMNH P.36289 lower*

75 Kriwet 2006 540 Figure 3D BMNH P.36290 lower*

76 Kriwet 2006 540 Figure 3H BMNH P.36291 lower*

77 Kriwet 2006 540 Figure 3G lower*

78 Kriwet 2006 540 Figure 3J lower*

79 Shimada 2007 513 Figure 2J lower*

80 Siverson et al. 2013 92 Fig. 4D NHMUK PV P73050 upper

81 Siverson et al. 2013 92 Fig. 4H NHMUK PV P73051 upper

82 Siverson et al. 2013 92 Fig. 4L NHMUK PV P73052 upper

83 Siverson et al. 2013 92 Fig. 4M NHMUK PV P73053 upper

84 Siverson et al. 2013 92 Fig. 4S NHMUK PV P73054 upper

85 Siverson et al. 2013 92 Fig. 4U NHMUK PV P73055 upper

86 Siverson et al. 2013 92 Fig. 4B' NHMUK PV P73056 upper

20

87 Siverson et al. 2013 92 Fig. 4C' NHMUK PV P73057 upper

88 Siverson et al. 2013 92 Fig. 4F' NHMUK PV P73058 upper

89 Siverson et al. 2013 94 Fig. 5A NHMUK PV P73059 upper

90 Siverson et al. 2013 94 Fig. 5E NHMUK PV P73060 upper

91 Siverson et al. 2013 94 Fig. 5G NHMUK PV P73061 upper

92 Siverson et al. 2013 94 Fig. 5J NHMUK PV P73062 upper

93 Siverson et al. 2013 94 Fig. 5O NHMUK PV P73063 upper

94 Siverson et al. 2013 94 Fig. 5Q NHMUK PV P73064 upper


96 Siverson et al. 2013 94 Fig. 5Y NHMUK PV P73066 upper



99 Siverson et al. 2013 95 Fig. 6A NHMUK PV P73069 lower

100 Siverson et al. 2013 95 Fig. 6E NHMUK PV P73070 lower

101 Siverson et al. 2013 95 Fig. 6L NHMUK PV P73071 lower

102 Siverson et al. 2013 95 Fig. 6O NHMUK PV P73072 lower

103 Siverson et al. 2013 96 Fig. 7C NHMUK PV P73073 lower

104 Siverson et al. 2013 96 Fig. 7H NHMUK PV P73074 lower

105 Siverson et al. 2013 96 Fig. 7I NHMUK PV P73075 lower

106 Siverson et al. 2013 96 Fig. 7M NHMUK PV P73076 lower

107 Siverson et al. 2013 96 Fig. 7T NHMUK PV P73077 lower

108 Siverson et al. 2013 96 Fig. 7W NHMUK PV P73078 lower

109 Siverson et al. 2013 96 Fig. 7Y NHMUK PV P73079 lower

110 Siverson et al. 2013 96 Fig. 7C' NHMUK PV P73080 lower

111 Siverson et al. 2013 96 Fig. 7G' NHMUK PV P73081 lower

112 Siverson et al. 2013 98 Fig. 9 (tooth LP3) NHMUK PV P73082 upper*


114 Siverson et al. 2013 97 Fig. 8D SMU 76857 upper*

115 Siverson et al. 2013 97 Fig. 8F SMU 76858 upper*

116 Siverson et al. 2013 97 Fig. 8H SMU 76859 upper*

117 Siverson et al. 2013 97 Fig. 8L SMU 76860 lower*

118 Siverson et al. 2013 97 Fig. 8R SMU 76861 lower*

119 Kriwet et al. 2009 321 Figure 4J MPZ 2005-4 lower*

120 Kriwet et al. 2009 321 Figure 4N MPZ 2005-4 lower*

121 Kriwet et al. 2009 321 Figure 4R MPZ 2005-4 lower*

122 Schmitz et al. 2010 286 Fig. 3.1 NLH 102.973 lower*





127 Schmitz et al. 2010 286 Fig. 3.13 NLH 102.979 upper (?)

128 Cuny et al. 2010 618 Fig. 2.5 OED5 lower*

129 Schlüter and Schwarzhans 1978 72 Tafel 2, Fig. 1 upper*

130 Benton et al. 2000 242 Fig. 13B lower*

131 Benton et al. 2000 242 Fig. 13D lower*

132 Siverson 1997 462 Figure 4A WAM 96.2.42 upper

21

133 Siverson 1997 462 Figure 4F WAM 96.2.43 upper

134 Siverson 1997 462 Figure 4H WAM 96.2.44 lower?

135 Siverson 1997 462 Figure 4J WAM 96.2.66 lower*

136 Siverson 1997 462 Figure 4L WAM 96.2.74 upper?

137 Siverson 1997 462 Figure 4O WAM 96.2.75 lower

138 Siverson 1997 462 Figure 4R WAM 96.2.80 lower*

139 Siverson 1997 462 Figure 4T WAM 96.2.81 lower

140 Siverson 1997 462 Figure 4W WAM 96.2.82 lower

141 Siverson 1997 462 Figure 4X WAM 96.2.85 lower*

142 Antunes and Cappetta 2002 159 Planche 7, Fig. 1a ANG 51 lower

143 Antunes and Cappetta 2002 165 Planche 10, Fig. 3a ANG 93 lower*

144 Antunes and Cappetta 2002 167 Planche 11, Fig. 10 ANG 119 lower

145 Bouaziz et al. 1988 337 Fig. 2K2 lower*

146 Bouaziz et al. 1988 337 Fig. 2L1 lower*

(continued) Row nr. Side (L=Left, R=Right side

of jaw) Relative.Position View Order

1 anterior labial Lamniformes

2 lateral labial Lamniformes

3 anterolateral labial Lamniformes






9 anterolateral lingual Lamniformes





14 parasymphyseal labial Lamniformes



17 labial Lamniformes

18 very lateral lingual Lamniformes

19 very lateral lingual Lamniformes











22


31 symphyseal? labial Lamniformes





36 posterior labial Lamniformes



39 lateral lingual Lamniformes



42 intermediate? labial Lamniformes

43 Lamniformes

44 L lateral labial Lamniformes

45 R lateral labial Lamniformes


47 L anterior labial Lamniformes








55 lateroposterior labial Lamniformes



















74 anterior? labial Lamniformes


23



78 lateroposterior lingual Lamniformes


80 R anterior labial Lamniformes

81 L parasymphyseal labial Lamniformes

82 R? anterior labial Lamniformes







89 R lateroposterior labial Lamniformes


91 L lateroposterior labial Lamniformes































24





126 posterolateral labial Lamniformes




130 labial Lamniformes*






136 R? lateral labial Lamniformes








144 anteriolateral labial Lamniformes



(continued) Row nr. Family Genus Species Continent Country

1 Cardabiodontidae Pseudoisurus aff. tomosus Asia (central) Kazakhstan



4 Paraisuridae Paraisurus macrorhiza Europe France

5 Pseudoscapanorhynchidae Leptostyrax bicuspidatus North America USA



8 Pseudoscapanorhynchidae Protolamna sokolovi Europe France



11 Pseudoscapanorhynchidae Pseudoscarpanorhynchus aff. compressidens Asia (central) Kazakhstan



14 Cretodus semiplicatus Asia (central) Kazakhstan






25

20 Dwardius siversoni Europe Russia



23 Dwardius sp. Asia (central) Kazakhstan

24 Dwardius sp. Asia (central) Kazakhstan

25 Priscusurus adruptodontus South America Peru

26 Priscusurus adruptodontus South America Peru

27 Cretoxyrhinidae Protolamna sp. Europe Poland



30 Eoptolamnidae Eoptolamna eccentrolopha Europe Spain













43 Odontaspididae Carcharias amonensis North America USA

44 Anacoracidae Squalicorax primaevus Europe England






50 Anacoracidae Squalicorax priscoserratus sp. nov. North America USA








58 Anacoracidae Squalicorax aff. S. baharijensis North America USA

59 Anacoracidae Squalicorax pawpawensis sp. nov. North America USA







26







72 incertae sedis Priscusurus adruptodontus sp. nov. South America Peru







79 Odontaspididae cf. Johnlongia sp. Europe England

80 Cretoxyrhinidae Cretoxyrhina vraconensis Asia (central) Kazakhstan
































27



114 Cretoxyrhinidae Cretoxyrhina vraconensis North America USA





119 incertae sedis Europe Spain



122 Eoptolamnidae Leptostyrax stychi sp. nov. Europe Germany


124 Eoptolamnidae Protolamna sarstedtensis sp. nov. Europe Germany




128 Cretoxyrhinidae ?Cretodus Africa Tunisia

129 Odontaspis sp. Africa Tunisia

130 Cretodus Africa Tunisia

131 Protolamna sp. Africa Tunisia

132 Cretoxyrhinidae Archaeolamna sp. Australia Australia



135 Cretoxyrhinidae Leptostyrax sp. Austalia Australia

136 Cretoxyrhinidae incertae sedis Australia Australia

137 Cretoxyrhinidae Cretolamna sp. Australia Australia

138 Cretoxyrhinidae Paraisurus aff. compressus Australia Australia

139 Odontaspididae Carcharias striatula Australia Australia

140 Odontaspididae Carcharias striatula Australia Australia

141 Anacoracidae Squalicorax primaevus Australia Australia

142 Anacoracidae Squalicorax sp. Africa Angola

143 Cretoxyrhinidae Leptostyrax macrorhiza Africa Angola

144 Cretoxyrhinidae Protolamna sp. Africa Angola

145 Cretoxyrhinidae Cretodus ? Africa Tunisia

146 Cretoxyrhinidae Protolamna sp. Africa Tunisia

(continued) Row nr. Locale

1 Kolbay

2 Kolbay

3 Kolbay

4 Aube, Paris basin

5 Lake Texoma, Texas

6 Lake Texoma, Texas

7 Roanoke, Texas

8 La Tuilière, Apt region, Vaucluse


28


11 Kolbay

12 Kolbay

13 Kolbay

14 Kolbay

15 Kolbay

16 Kolbay

17 Kolbay

18 Kolbay

19 Kolbay

20 Stojlenski quarry, Stary Oskol, near Belgorod.



23 Kolbay

24 Kolbay

25

26

27 Clay pit in Wawał



30 Vallipón in NW part of Maestrat sub-basin near the city of Castellote (approximately 150 km SE of Zaragoza)













43 Champion shell bed, Kansas

44 Gault clays of Folkestone, NE of Leighton Buzzard






50 Motorola locality, Pawpaw shale, Texas






29

















72 Locality 3, Ammonite Valley, Amotape-Tahuin Massif, 27 miles east of Lobitos







79

80 Kolbay, Mangysklak






















30













114 Motorola site, Mortoniceras rostratum Zone, Pawpaw shale, Texas





119 Oliete subbasin, Iberian basin, NE-Spain



122 'Gott'' Clay pit approx. 20 km SE of Hannover, near the city of Sarstedt, northern Germany






128 Oum ed Diab

129 Near Ksar Krerachfa, south of the city Medenine, south Tunisia

130 Tataouine region, southern Tunisia

131 Tataouine region, southern Tunisia

132 Black Dam, lower part of Gearle Siltstone, Giralia Anticline, Southern Carnarvon basin, Western Australia










142 Locality 19, Cubal da Hanha, 19 km NE of Lobito, Benguela basin



145 Locality RH 45, Foum Tatahouine region, southern Tunisia

146 Locality RH 45, Foum Tatahouine region, southern Tunisia

(continued)

31

Row nr. Formation Era Period Epoch Sub Age

1 Mesozoic Cretaceous Lower late Albian



4 Mesozoic Cretaceous Lower Albian




8 Mesozoic Cretaceous Lower middle to late Albian

















25 Muerto Limestone formation

Mesozoic Cretaceous Lower middle Albian



27 Mesozoic Cretaceous Lower late Valanginian



30 Artoles formation Mesozoic Cretaceous Lower late Barremian













43 Kiowa formation Mesozoic Cretaceous Lower late Albian

44 Mesozoic Cretaceous Lower middle Albian


32

46 Mesozoic Cretaceous Lower upper Albian


48 Mesozoic Cretaceous Lower upper Albian


50 Pawpaw formation Mesozoic Cretaceous Lower late Albian























Mesozoic Cretaceous Lower middle? Albian













79 Mesozoic Cretaceous Lower early Aptian

80 Mesozoic Cretaceous Lower latest late/earliest early Albian/Cenomanian











33





























119 upper Blesa formation Mesozoic Cretaceous Lower late Barremian



122 Mesozoic Cretaceous Lower early Barremian






128 Aïn el Guettar formation, Oum ed Diab group

Mesozoic Cretaceous Lower early Albian

129 Mesozoic Cretaceous Lower

130 Chenini formation Mesozoic Cretaceous Lower early Albian






34










145 Chénini formation Mesozoic Cretaceous Lower early Albian


35

Table 2. Dataset containing specimen analyzed in this paper. All data was collected and entered into the dataset as found in the published material it was collected from. If a piece of information was unspecified in the litterature which it came from then information was assumed when possible, this was marked with an asterisk (*). Every row number represents one specimen each. Row nr. Source Page Image.Label Specimen Dental.Unit

1 Siverson 1997 462 Figure 4A WAM 96.2.42 upper

2 Siverson 1997 462 Figure 4H WAM 96.2.44 lower?


4 Cappetta 2012 255 Figure 233B UM KOB 4 lower*

5 Cappetta 2012 255 Figure 233E UM KOB 5 lower

6 Cappetta 2012 255 Figure 233F UM KOB 6 upper

7 Benton et al. 2000 242 Fig. 13B lower*

8 Bouaziz et al. 1988 337 Fig. 2K2 lower*

9 Siverson 1997 462 Figure 4O WAM 96.2.75 lower

10 Siverson et al. 2013 92 Fig. 4D NHMUK PV P73050 upper

11 Siverson et al. 2013 94 Fig. 5A NHMUK PV P73059 upper

12 Siverson et al. 2013 94 Fig. 5E NHMUK PV P73060 upper

13 Siverson et al. 2013 94 Fig. 5G NHMUK PV P73061 upper

14 Siverson et al. 2013 94 Fig. 5J NHMUK PV P73062 upper

15 Siverson et al. 2013 94 Fig. 5O NHMUK PV P73063 upper

16 Siverson et al. 2013 94 Fig. 5Q NHMUK PV P73064 upper


18 Siverson et al. 2013 94 Fig. 5Y NHMUK PV P73066 upper



21 Siverson et al. 2013 92 Fig. 4H NHMUK PV P73051 upper

22 Siverson et al. 2013 95 Fig. 6A NHMUK PV P73069 lower

23 Siverson et al. 2013 95 Fig. 6O NHMUK PV P73072 lower

24 Siverson et al. 2013 96 Fig. 7H NHMUK PV P73074 lower

25 Siverson et al. 2013 96 Fig. 7M NHMUK PV P73076 lower

26 Siverson et al. 2013 96 Fig. 7T NHMUK PV P73077 lower

27 Siverson et al. 2013 96 Fig. 7W NHMUK PV P73078 lower

28 Siverson et al. 2013 92 Fig. 4L NHMUK PV P73052 upper

29 Siverson et al. 2013 96 Fig. 7C' NHMUK PV P73080 lower

30 Siverson et al. 2013 96 Fig. 7G' NHMUK PV P73081 lower



33 Siverson et al. 2013 97 Fig. 8D SMU 76857 upper*

34 Siverson et al. 2013 97 Fig. 8H SMU 76859 upper*

35 Siverson et al. 2013 97 Fig. 8L SMU 76860 lower*

36 Siverson et al. 2013 92 Fig. 4M NHMUK PV P73053 upper

37 Siverson et al. 2013 92 Fig. 4S NHMUK PV P73054 upper

38 Siverson 1997 462 Figure 4L WAM 96.2.74 upper?

39 Cappetta 2012 257 Figure 235A UM STO 1 lower*

40 Cappetta 2012 257 Figure 235C UM STO 2 lower*

36

41 Cappetta 2012 257 Figure 235F UM STO 3 lower*

42 Cappetta 2012 257 Figure 235I UM KOB 31 lower*

43 Cappetta 2012 257 Figure 235K UM KOB 32 lower*

44 Kriwet et al. 2008 283 Figure 3C MPZ 2005-13 lower*

45 Kriwet et al. 2008 282 Figure 2W MPZ 2005-10 lower*

46 Siverson 1997 462 Figure 4J WAM 96.2.66 lower*


48 Kriwet 2006 540 Figure 2A BMNH P.36287 lower

49 Cappetta 2012 261 Figure 240D UM PER 2 lower*




53 Schmitz et al. 2010 286 Fig. 3.13 NLH 102.979 upper (?)

54 Cappetta 2012 240 Figure 220C UM TUI 35 lower

55 Antunes and Cappetta 2002 167 Planche 11, Fig. 10 ANG 119 lower



















74 Siverson 1997 462 Figure 4X WAM 96.2.85 lower*

75 Smart 2007 377 Figure 2A NHM P 66356 lower

76 Smart 2007 377 Figure 2C NHM P 66357 lower

77 Smart 2007 378 Figure 3E NHM P 66361 upper


79 Siverson 2007 et al. 943 Text-fig. 3C SMU 76282 lower*

80 Siverson 2007 et al. 943 Text-fig. 3F SMU 76284 lower*

81 Siverson 2007 et al. 943 Text-fig. 3G SMU 76285 lower*

82 Siverson 2007 et al. 943 Text-fig. 3J SMU 76286 lower*

83 Siverson 2007 et al. 943 Text-fig. 3L SMU 76287 lower*

84 Siverson 2007 et al. 943 Text-fig. 3N SMU 76288 lower*

85 Siverson 2007 et al. 943 Text-fig. 3P SMU 76289 lower*

(continued)

37

Row nr. Side (L=Left, R=Right side of jaw)

Relative.Position View Order





















21 L parasymphyseal labial Lamniformes

















38 R? lateral labial Lamniformes








38







52 posterolateral labial Lamniformes



55 anteriolateral labial Lamniformes





















76 R lateral labial Lamniformes










(continued) Row nr. Family Genus Species Continent Country



3 Cretodus semiplicatus Asia (central)

Kazakhstan

39


Kazakhstan


Kazakhstan


Kazakhstan

7 Cretodus Africa Tunisia

8 Cretoxyrhinidae Cretodus ? Africa Tunisia

9 Cretoxyrhinidae Cretolamna sp. Australia Australia

10 Cretoxyrhinidae Cretoxyrhina vraconensis Asia (central)

Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan


Kazakhstan

33 Cretoxyrhinidae Cretoxyrhina vraconensis North America

USA


USA


USA


Kazakhstan


Kazakhstan

38 Cretoxyrhinidae incertae sedis Australia Australia




42 Dwardius sp. Asia (central)

Kazakhstan

40

43 Dwardius sp. Asia (central)

Kazakhstan



46 Cretoxyrhinidae Leptostyrax sp. Austalia Australia


48 incertae sedis Priscusurus adruptodontus sp. nov.

South America

Peru

49 Priscusurus adruptodontus South America

Peru

50 Eoptolamnidae Protolamna sarstedtensis sp. nov.

Europe Germany


Europe Germany


Europe Germany


Europe Germany


55 Cretoxyrhinidae Protolamna sp. Africa Angola

56 Cardabiodontidae Pseudoisurus aff. tomosus Asia (central)

Kazakhstan


Kazakhstan


Kazakhstan

59 Pseudoscapanorhynchidae Pseudoscarpanorhynchus aff. compressidens Asia (central)

Kazakhstan

60 Pseudoscapanorhynchidae Pseudoscarpanorhynchus aff. compressidens Asia (central)

Kazakhstan

61 Anacoracidae Squalicorax aff. S. baharijensis North America

USA

62 Anacoracidae Squalicorax pawpawensis sp. nov.

North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA


North America

USA

74 Anacoracidae Squalicorax primaevus Australia Australia




78 Anacoracidae Squalicorax priscoserratus sp. nov.

North America

USA


North America

USA


North America

USA


North America

USA

82 Anacoracidae Squalicorax priscoserratus sp. North USA

41

nov. America


North America

USA


North America

USA


North America

USA

(continued) Row nr. Formation Era Period Epoch Sub Age










10 Mesozoic Cretaceous Lower latest late/earliest early

Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian


Albian/Cenomanian



42



Albian/Cenomanian


Albian/Cenomanian













































43







Documents

Disparity of Early Cretaceous Lamniformes sharks