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Johan Lindgren

Johan Lindgren

Universitetslektor

Johan Lindgren

Cenomanian-Campanian (Late Cretaceous) mid-palaeolatitude sharks of Cretalamna appendiculata type

Författare

  • Mikael Siversson
  • Johan Lindgren
  • Michael G. Newbrey
  • Peter Cederstrom
  • Todd D. Cook

Summary, in English

The type species of the extinct lamniform genus Cretalamna, C. appendiculata, has been assigned a 50 Ma range (Albian-Ypresian) by a majority of previous authors. Analysis of a partly articulated dentition of a Cretalamna from the Smoky Hill Chalk, Kansas, USA (LACM 128126) and isolated teeth of the genus from Cenomanian to Campanian strata of Western Australia, France, Sweden, and the Western Interior of North America, indicates that the name of the type species, as applied to fossil material over the last 50 years, represents a large species complex. The middle Cenomanian part of the Gearle Siltstone, Western Australia, yielded C. catoxodon sp. nov. and "Cretalamna" gunsoni. The latter, reassigned to the new genus Kenolamna, shares several dental features with the Paleocene Palaeocarcharodon. Early Turonian strata in France produced the type species C. appendiculata, C. deschutteri sp. nov., and C. gertericorum sp. nov. Cretalamna teeth from the late Coniacian part of the Smoky Hill Chalk in Kansas are assigned to C. ewelli sp. nov., whereas LACM 128126, of latest Santonian or earliest Campanian age, is designated as holotype of C. hattini sp. nov. Early Campanian deposits in Sweden yielded C. borealis and C. sarcoportheta sp. nov. A previous reconstruction of the dentition of LACM 128126 includes a posteriorly situated upper lateroposterior tooth, with a distally curved cusp, demonstrably misplaced as a reduced upper "intermediate" tooth. As originally reconstructed, the dentition resembled that of cretoxyrhinids (sensu stricto) and lamnids. Tooth morphology, however, indicates an otodontid affinity for Cretalamna. The root is typically the most diagnostic feature on an isolated Cretalamna tooth. This porous structure is commonly abraded and/or corroded and, consequently, many collected Cretalamna teeth are indeterminable at species level.

Avdelning/ar

  • Berggrundsgeologi

Publiceringsår

2015

Språk

Engelska

Sidor

339-384

Publikation/Tidskrift/Serie

Acta Palaeontologica Polonica

Volym

60

Issue

2

Dokumenttyp

Artikel i tidskrift

Förlag

Instytut Paleobiologii PAN

Ämne

  • Geology

Nyckelord

  • Lamniformes
  • Otodontidae
  • Cretaceous
  • Australia
  • France
  • Sweden
  • USA

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 0567-7920