A new Jurassic cow shark (Chondrichthyes, Hexanchiformes) with comments on Jurassic hexanchiform systematics

Kriwet, Jürgen; Klug, Stefanie

doi:10.1007/978-3-0348-0300-7_9

Cited by 1 publication

(4 citation statements)

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“…The root is poorly preserved in both examples. The teeth can be attributed to a hexanchiform shark, whose fossil record extends from the Early to Late Jurassic (Kriwet & Klug, 2011). Hexanchiformes is a plesiomorphic group of squalomorph sharks, characterized by numerous extinct genera and three extant ones, with a widespread geographical distribution.…”

Section: Taphonomy and Associated Shark Teethmentioning

confidence: 99%

“…Hexanchiformes is a plesiomorphic group of squalomorph sharks, characterized by numerous extinct genera and three extant ones, with a widespread geographical distribution. Since the fossil record consists mainly of isolated teeth, hexanchiform sharks are recognized by a combination of dental characters (Kriwet & Klug, 2011). All Jurassic hexanchiforms described to date can be referred to the extinct family Crassonotidae, which is defined based on root morphology (Kriwet & Klug, 2011, 2014).…”

Section: Taphonomy and Associated Shark Teethmentioning

confidence: 99%

“…Since the fossil record consists mainly of isolated teeth, hexanchiform sharks are recognized by a combination of dental characters (Kriwet & Klug, 2011). All Jurassic hexanchiforms described to date can be referred to the extinct family Crassonotidae, which is defined based on root morphology (Kriwet & Klug, 2011, 2014). Thus, although root morphology cannot be accurately assessed in the current example, referral to Crassonotidae is probable.…”

Section: Taphonomy and Associated Shark Teethmentioning

confidence: 99%

“…Thus, although root morphology cannot be accurately assessed in the current example, referral to Crassonotidae is probable. The only hexanchiform reported to date from the Late Jurassic of Italy belongs to Notidanus insignis Seguenza, 1887, from the Oxfordian of Sicily (Seguenza, 1887; Kriwet & Klug, 2011).

Figure 8. Multicuspid shark teeth found on the same slab with the skeleton of Gengasaurus nicosiai MSVG 39617, attributed to Hexanchiformes: (a) best-preserved tooth in lingual view, with mesial and distal cusplets clearly visible; (b) the second preserved tooth in lingual?…”

Section: Taphonomy and Associated Shark Teethmentioning

confidence: 99%

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The first ophthalmosaurid ichthyosaur from the Upper Jurassic of the Umbrian–Marchean Apennines (Marche, Central Italy)

et al. 2016

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The first ophthalmosaurid ichthyosaur from the Upper Jurassic deposits of the Central–\ud Northern Apennines (Marche, Italy) is here described for the first time. The specimen is relatively\ud complete and is referred to Gengasaurus nicosiai gen. et sp. nov. based on a unique combination of\ud characters, including a peculiar condition of the preaxial accessory facet on the humerus. The faunal\ud association of the ichthyosaur-bearing level indicates a late Kimmeridgian – earliest Tithonian age,\ud and its finding contributes significantly to our knowledge of the diversity of Late Jurassic ichthyosaurs\ud from the Western Tethys. Two shark teeth assigned to the order Hexanchiformes were also recovered\ud in association with the ichthyosaur specimen, suggesting that scavenging of the carcass might have\ud occurred. Gengasaurus can be referred to Ophthalmosauridae based on the reduced extracondylar\ud area of the basioccipital, and the presence of a preaxial digit. It differs from Ophthalmosaurus spp.\ud in several respects, including the shape of the posterior basisphenoid, the shape of the supraoccipital,\ud the anteriorly deflected preaxial facet of the humerus, and a proximodistally shortened ulna. The new\ud taxon actually shares diagnostic characters with both members of the two main lineages recovered in\ud previous phylogenetic analyses,more nested within Ophthalmosauridae. The affinities of Gengasaurus\ud to genera from both the northern and southern hemispheres also suggest that connectivity between\ud pelagic habitats was high during the early Late Jurassic, allowing dispersal of some forms, followed\ud by local, endemic divergence

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Section: Taphonomy and Associated Shark Teethmentioning

confidence: 99%