Erected as Cretalamna1 by Glikman (1958: 570), this genus has a worldwide fossil record, but is largely limited to isolated teeth and vertebral centra2. The teeth of C. appendiculata (AGASSIZ 1843) are common in Cretaceous marine exposures (extending into the Paleocene in Europe and Lower Eocene of Africa), including those of the Middle Atlantic States, and easily identified. Cappetta (1987: 99) notes that other members of this genus are more localized in time and distribution.

Welton & Farish (1993: 103) include C. appendiculata and C. woodwardi HERMAN 1977 in their Cretaceous fauna. Siverson (1996) deemed C. woodwardi synonymous with Pseudoisurus tomosus GLIKMAN 1957 and was of the opinion that these Texas teeth, ascribed to C. woodwardi, were in fact, C. appendiculata.

Kent (1994: 50) further expanded the possibilities in the Chesapeake region by listing five species: C. appendiculata, C. appendiculata lata (AGASSIZ 1843), C. appendiculata pachyrhiza HERMAN 1977, C. biauriculata maroccana and C. lerichei (CASIER 1946). The latter species was originally included on this website under Serratolamna but moved to Brachycarcharias following Cappetta & Nolf 2005.

Cretalamna appendiculata

The teeth of C. appendiculata (no attempt will be made to differentiate the sub-species) are best characterized by their smooth triangular cusp, broad triangular lateral cusplets and a bilobate root, which has a lingual protuberance and foramen but lacks a nutrient groove. The crown of anterior teeth is elongated and erect and in laterals, the cusp is shorter and distally directed (more acutely in upper teeth). The basal margin of the root is "U" in shape.

Dentition-design

Shimada (2007) described a partially articulated3 C. appendiculata skeleton from the Smoky Hills Chalk (Upper Cretaceous, Logan, Co., KS) housed in the LA County Museum (LACM 128126). He concluded that the species, based on morphological features, was a medium-sized (to 3m) pelagic lamniform with a cutting dentition designed for generalized feeding. He noted that the dentition-design did not compare well with that of Cretoxyrhina mantelli but was much more lamnid-like; he elected to leave this genus ascribed to Cretoxyrhinidae, but questioned the validity of that assignment.

The largely disarticulated teeth from this specimen were arranged by Shimada following a series of described steps (p 588) which might be briefly summarized as tooth size and cusp inclination; upper vs lower determinations were based on cusp width and thickness. Once complete, he found the arrangement could be validated (in part) by the anterior/medio-lateral crown tips articulated in the right palatoquadrate (p 591). Remaining upper tooth-positions mapped to "depressions for tooth rows in the inner surface of the palatoquadrate" (Shimada pers com 2007). In this paper, the material appears to be excellent, the methodology well defined (except for the underlying rule for tooth-orientation when capturing metrics) and the validation reasonable -- characteristics often lacking with reconstructed dentition-sets.

Although the image of the complete dentition-set arrangement (p 593) was too small to be of any use, the large three perspective images (labial, lingual & lateral) for each tooth in the reconstruction were excellent. In viewing this tooth-set, it was assumed that all (or at least most) tooth-designs were represented in the reconstruction. With that said, certain aspects of the arrangement (ref Fig ) were questionable (for reference purposes, his tooth-positions have been numbered one-up):

  • Two upper "parasymphyseals" were included, but the first was a crown only of similar size and shape of the complete tooth included as the second. There was evidence neither to suggest that there were two positions nor to support their placement in the upper quadrates
  • The upper 12th tooth is a virtual clone of the lower 8th; one of them is likely incorrect. Because the distal edge is more erect (less distally curved) than the upper 11th, it is more likely a lower.

    The questions raised by this cursory inspection led to additional examination of the arrangement using macrophagous lamniform propensities. Lacking both 'hands-on-experience' and basal perspectives of these specimens, it can only be said there are concerns.

  • Based on its size, shape and positioning, Shimada's upper 5th tooth (whether called a UA3 or Intermediate) would be the third tooth of that anterior hollow (bulla). Lacking a basal perspective which will often provide evidence of hollow-position, it can only be said that the root appears too symmetrical and the cusp too short and distally inclined.
  • The significant differences between upper and lower file counts appears questionable when some 120 teeth (a very good representative example) are present.

    Relying solely on the available images in the paper and following positional propensities (most importantly root design) within extant macrophagous lamniform dentitions, I came up with an alternate interpretation (Fig ). Each of us acknowledges gradational heterodonty by our methodology, however Kenshu's description appears to be quadrate-based as might be applied to a carcharhinid, while mine is hollow-based (sensu Siverson 1999; more appropriate in my opinion for a lamniform).

    Unlike Shimada's (1997) Cretoxyrhina arrangement, which I've duplicated with a collateral tooth-set, this Cretalamna arrangement is suspect in my opinion. Without hands-on experience with this specimen, I can only say that I question his determination and it (as mine) might best be viewed as proposed arrangements. Based on his arrangement, Kenshu was quite correct in leaving this taxon in the cretoxyrhinid bucket -- the dentition does not reflect an otodontid design. In contrast, the alternate arrangement would reflect both otodontid tooth and dentition-designs.

    Cretalamna maroccana

    Arambourg (1935) erected the subspecies Lamna biauriculata maroccana for what he deemed a broader variation of this tooth-design. Cappetta (1987:99) included these teeth as Cretolamna biauriculata maroccana as did Kent (1994: 50). Landemaine (1991:15) did not include C. biauriculata VON ZITTEL, in Wanner, 1902 or C. b. maroccana in his Serratolamna description. Welton & Farish (1993: 112, fig 6) included as Serratolamna serrata this tooth-design. Case & Cappetta (1997:138) raised this tooth-design to the species level by including as C. maroccana. Less common than C. appendiculata, C. maroccana are knopwn from Late Cretaceous sediments of the Western Atlantic and Gulf Coast to Texas. They are identifiable by their dual lateral cusplets and weakly concave basal root margin.

    Interior sea

    On rare occasions, the chalk of Kansas yields a Cretalamna tooth. Time wise (late Coniacian) these should be ascribed to C. appendiculata, however their crowns can be quite broad. Welton & Farish (1993: 105) found teeth similar to those illustrated above (Fig ) in the Turonian of Texas and listed them as C. woodwardi, but speculated that they might be C. appendiculata; a similar difficulty was encountered with the Smoky Hill anteriors. Mikael Siverson (pers. com. 1998) felt certain that these teeth are C. appendiculata noting the deep-water environment (note how much broader these crowns are than on their Campanian and Maastrichtian counterparts). Bourdon et al (2011:31) reported the genus from the Santonian of New Mexico, but did not refine their determination to the specific level.

    The Paleogene record

    In the Paleogene, very similar tooth-designs are ascribed to both Otodus and Cretalamna based largely on differences of root shape. The below specimens have been ascribed to Cretalamana by those more experienced than myself.

    Notes:  
    1. When this page was first erected (1998), there was controversy as to the proper spelling of the name. It was published with an 'a' (Cretalamna) although the author had intended it to be spelled with an 'o' (Cretolamna). Elasmo.com originally followed Glikman's intentions. David Ward (pers com 2006) noted: "The original spelling, etymologically correct, but used only once, was Cretalamna. All subsequent spellings were Cretolamna. Glyckman himself said that the first spelling was an error, but this makes no difference... Cretalamna was used by Mikael in Siverson (1999:59). Henri [Cappetta] subsequently put in an application to the ICZN to have this spelling suppressed..." With that said, David Ward (pers com 2007) notes that the ICZN was convinced by the 'spirit' of Cappetta's arguments and would subsequently (2000) erect Article 33.3.1 which would address this situation in the future.
    In subsequent years, the spelling "Cretalamna" has become more common in the literature and it is unlikely that there will be a return to the usage of "Cretolamna".
    2. Applegate (1970) reported a fragmentary skeleton from the Upper Cretaceous of Alabama.
    3. This specimen consisted of partial palatoquadrates & Meckel’s cartilages, 35 vertebrae and 120 (mostly disarticulated) teeth.


    Selected References

    Agassiz, J., 1833-43. Recherches sur les poisons fossils, 3. Imprimerie de Petitpierre, Neuchatel, 390 + 32 pp.
    Applegate, S., 1970. The vertebrate fauna of the Selma Formation in Alabama. Part VIII: The fishes. Fieldiana, Geology Memoirs 3:385-433.
    Bourdon, J., Wright, K., Lucas, S.G., Spielmann, J.A. and Pence, R., 2011. Selachians from the Upper Cretaceous (Santonian) Hosta Tongue of the Point Lookout Sandstone, central New Mexico. New Mex. Mus. Nat. His. and Sc., Bulletin 52; 54pp.
    Cappetta, H., 1987. Chondrichthyes II. Mesozoic and Cenozoic Elasmobranchii. In: Handbook of Paleoichthyologie, vol. 3b, Gustav Fischer Verleg, Stuttgart, 193 pp.
    Cappetta, H & Nolf, D, 2005. Revision de quelques Odontaspidae (Neoselachii: Lamniformes) du Paleocene et de l'Eocene du Bassin de la mer du Nord Bulletin de l'institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre 75: 237-266.
    Case, G. R., and Cappetta, H. 1997. A new selachian fauna from the Late Maastrichtian of Texas. Münchner Geowissenschaftliche Abhandlungen 34:131-189.
    Glikman, L., 1958. [Russian: Rates of evolution in lamnoid sharks]. Doklady Akademia Nauk, S.S.S.R. 123:568-571.
    Kent, B., 1994. Fossil Sharks of the Chesapeake Region. Egan Rees & Boyer, Maryland. 146 pp
    Landemaine, O., 1991. Sélaciens nouveaux du crétacé supérieur du sud-ouest de la France quelques apports a la systematique des elasmobranches. Société Amicale des Géologues Amateurs, Muséum National d'Histoire Naturelle, Paris, no. 1, 45pp
    Schwimmer, D., 1986. Late Cretaceous fossils from the Blufftown Formation (Campanian) in western Georgia. The Mosasaur. Delaware Valeey Paleontological Society. pp 109-119.
    Shimada, K., 1997. Dentition of the Late Cretaceous lamniform shark, Cretoxyrhina mantelli, from the Niobrara Chalk of Kansas. Journal of Vertebrate Paleontology 17:269-279.
    Shimada, K., 2007. Skeletal and dental anatomy of the lamniform shark Cretalamna appendiculata, from the Upper Cretaceous Niobrara Chalk of Kansas. Journal of Vertebrate Paleontology 27:584-602.
    Siverson, M., 1996. Lamniform sharks of the mid Cretaceous Alinga Formation and Beedagong Claystone, Western Australia. Palaeontology 39:813-849.
    Siverson, M., 1999. A new large lamniform shark from the uppermost Gearle Siltstone (Cenomanian, Late Cretaceous) of Western Australia. Transactions of the Royal Society of Edinburgh: Earth Sciences 90:49-65.
    Underwood, C. J. and Cumbaa, S. L., 2010. Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontolgy.Vol. 53(4): 903-944.
    Wanner, J. 1902. Die faune der obersten weissen Kreide der libyschen Wüste. Palaeontographica, 30:2, 91-152. [Fauna the highest white chalk of the Libyan desert]
    Welton, B. and R. Farish, 1993. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. Before Time, Texas. 204 pp.

     

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