Nanocorax microserratodon

(SHIMADA, 2008)


Classification: Elasmobranchii Lamniformes Anacoracidae

Reference of the original description
SHIMADA, K. (2008)
New anacoracid shark from Upper Cretaceous Niobrara Chalk of western Kansas, U.S.A. Journal of Vertebrate Paleontology, 28 (4): 1189–1194

Synonyms / new combinations and misspellings
Squalicorax microserratodon

Types
Nanocorax microserratodon

Squalicorax microserratodon
Holotype: KUVP: 141876;


Description:


Citation: Nanocorax microserratodon (SHIMADA, 2008): In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 06/2021

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Description
Original diagnose after Shimada (2008) p. 1189 [4646]: Small teeth (measuring up to approximately 4 mm in total tooth height in holotype); crown highly asymmetrical because of distally inclined, triangular cusp and gently convex distal heel; lingual face of cusp and distal heel more convex than their labial face; mesial cusp margin gently convex or slightly indented at middle; distal cusp margin straight or slightly concave except near its apex that tends to be slightly convex; distal heel apicobasally low and mesiodistally short, and poorly demarcated from distal edge of cusp in more erect, presumably anteriorly located teeth; small but well-defined serrations along cusp and distal heel margins; distally directed cusp apex not extending beyond distal demarcation of distal heel; tooth neck between crown and root on lingual face rather narrow; crown base on labial side weakly overhanging bilobed root; basal concavity of root between lobes gently arched ( shallow and broad); lingual root face gently separated into apical and basal faces without lingual protuberance at middle; many minute shallow pits (= porous) particularly on basal face of lingual root face as well as middle of labial root face.

Remarks
valid after Guinot et al. (2013) p. 623 [24889];


References
CONDAMINE, F.L. & ROMIEU, J. & GUINOT, G. (2019)
Climate cooling and clade competition likely drove the decline of lamniform sharks. Proceedings of the National Academy of Sciences of the United States of America, 116 (41) 20584-20590
DOI: 10.1073/pnas.1902693116
GUINOT, G. & UNDERWOOD, C.J. & CAPPETTA, H. & WARD, D.J. (2013)
Sharks (Elasmobranchii: Euselachii) from the Late Cretaceous of France and the UK. Journal of Systematic Palaeontology, 11 (6): 589–671
DOI: 10.1080/14772019.2013.767286
GUINOT, G. (2013)
Regional to global patterns in Late Cretaceous selachian (Chondrichthyes, Euselachii) diversity. Journal of Vertebrate Paleontology, 33 (3): 521–531
DOI: 10.1080/02724634.2013.740116
GUINOT, G. (2013)
Late Cretaceous elasmobranch palaeoecology in NW Europe. Palaeogeography, Palaeoclimatology, Palaeoecology, 388: 23–41
DOI: 10.1016/j.palaeo.2013.07.027
SHIMADA, K. (2008)
New anacoracid shark from Upper Cretaceous Niobrara Chalk of western Kansas, U.S.A. Journal of Vertebrate Paleontology, 28 (4): 1189–1194
DOI: 10.1671/0272-4634-28.4.1189