Skeletal anatomy of the Late Cretaceous shark,Squalicorax (Neoselachii: Anacoracidae)

Shimada, Kenshu; Cicimurri, David J.

doi:10.1007/bf02990187

Cited by 54 publications

(41 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several of these ‘species’ (as defined in the literature) are merely broad stages of dental evolution within Squalicorax and therefore represent artificial form‐species. This was, prior to our study, the case with S. volgensis , as the name had been applied to a heterogeneous mix of small, poorly serrated teeth from Upper Albian to Turonian strata (by, for example, Siverson 1996; Cappetta and Case 1999; Cicimurri 2001; Shimada and Cicimurri 2005). On a positive note, there has been a sharp drop in the number of new, poorly diagnosed nominal species of anacoracids added to the scientific literature over the last couple of decades.…”

Section: Discussionmentioning

confidence: 99%

“…The anacoracids were common, medium‐sized to large sharks (see Shimada and Cicimurri 2005) inhabiting temperate to tropical neritic waters during their approximately 45‐myr range from the Albian to Maastrichtian stages of the Cretaceous. They evolved rapidly and, based on their size range, dentition and abundance, probably occupied a position within the marine food chain comparable with today's requiem sharks (Carcharhinidae).…”

mentioning

confidence: 99%

“…They evolved rapidly and, based on their size range, dentition and abundance, probably occupied a position within the marine food chain comparable with today's requiem sharks (Carcharhinidae). Most of the anatomical features of the skeleton and teeth indicate that anacoracids were lamniform sharks (Compagno 1988; Shimada and Cicimurri 2005).…”

mentioning

confidence: 99%

“…Schwimmer et al . 1997; Shimada and Cicimurri 2005) is hampered by a plethora of poorly defined and inadequately illustrated nominal species. The species concept used by various authors for even the most widely cited anacoracids is often vague.…”

mentioning

confidence: 99%

“…1997; Dortangs et al . 2002; Everhart 2005) and formidable predators near the top of the food chain (see Shimada and Cicimurri 2005), a revision of the group is long overdue. This work is intended to be the first in a series of revisions of North American and European nominal anacoracids.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Anacoracid Sharks From the Albian (Lower Cretaceous) Pawpaw Shale of Texas

Siverson¹,

Lindgren²,

Kelley³

2007

Palaeontology

View full text Add to dashboard Cite

Recent collecting from the Pawpaw Shale in northeast Texas has yielded several hundred teeth of anacoracid sharks. The material allows for a much-needed revision of the Late Albian anacoracids from North America. The previously recognized Squalicorax sp., also referred to as S. volgensis in more recent publications, is a mix of two different species: S. priscoserratus sp. nov. and S. pawpawensis sp. nov. In addition to these two new species, a single tooth is assigned to S. aff. S. baharijensis. Our data indicate that anacoracids were a considerably more diverse group in the North American Cretaceous than previously thought. We attribute much of the underestimation of diversity to vague species concepts, poor preparation techniques and the associated lack of attention to certain dental features, in particular neck morphology, root surface porosity and the root's vascularization.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Anacoracid Sharks From the Albian (Lower Cretaceous) Pawpaw Shale of Texas

Siverson¹,

Lindgren²,

Kelley³

2007

Palaeontology

View full text Add to dashboard Cite

show abstract

Enameloid microstructure of the serrated cutting edges in certain fossil carcharhiniform and lamniform sharks

Andreev

2010

Microscopy Res & Technique

View full text Add to dashboard Cite

The triple-layered enameloid organization of neoselachian teeth has proven to be a reliable systematic character of the group. This study uses scanning electron microscopy to investigate the orientation of the parallel enameloid bundles in the area of the serrated cutting edges in certain fossil elasmobranchs. The examined teeth come from two Upper Cretaceous Squalicorax species and the Upper Miocene carcharhiniforms Galeocerdo sp., Carcharhinus sp., and Hemipristis serra. The parallel bundles are revealed by surface etching, which removes the superficial shiny-layered enameloid. In the teeth of Squalicorax, the bundles around the cutting edge bend once, before they reach the serrations. The studied carcharhiniform species show a more complicated pattern with a change of parallel bundle course inside the serrations. H. serra teeth do not display the first bending of the bundles, whereas it was present in the other two carcharhiniforms. The course of the crystalline bundles in both Squalicorax species is not affected by the presence of the serrations, regardless of the twofold difference in tooth size between them. In the carcharhiniform species, the bended bundles occur within the primary and secondary serrations and are always associated with them. This feature might have functional significance by strengthening the cutting edge or could simply develop as a consequence of the enameloid mineralization around the individual serrae.

show abstract