The taxonomic value of rostral nodes of extinct sharks, with comments on previous records of the genus Lamna (Lamniformes, Lamnidae) from the Pliocene of Lee Creek Mine, North Carolina (USA)
Mollen, F.H.; Jagt, J.W.M. (2012). The taxonomic value of rostral nodes of extinct sharks, with comments on previous records of the genus Lamna (Lamniformes, Lamnidae) from the Pliocene of Lee Creek Mine, North Carolina (USA). Acta Geol. Pol. 62(1): 117-127
In: Acta Geologica Polonica. Muzeum Ziemi: Warszawa. ISSN 0001-5709; e-ISSN 2300-1887, meer
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Fossils
Geological time > Phanerozoic > Geological time > Cenozoic > Tertiary > Cenozoic > Neogene > Pliocene
Identification
Cosmopolitodus; Lamna ditropis Hubbs & Follett, 1947 [WoRMS]; Lamna nasus (Bonnaterre, 1788) [WoRMS]; Lamnidae Bonaparte, 1835 [WoRMS]; Megaselachus; Otodontidae
USA, North Carolina [Marine Regions]
Marien/Kust |
| Author keywords |
Lamnidae; Otodontidae; Lamna nasus; Lamna ditropis; Carcharodon;Cosmopolitodus; Megaselachus; Parotodus; Rostrum; Rostral node; CT scans |
| Auteurs | | Top |
- Mollen, F.H., meer
- Jagt, J.W.M.
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| Abstract |
Shark rostral nodes from the Yorktown Formation (Zanclean, early Pliocene) of Lee Creek Mine, North Carolina (USA), previously assigned to the genus Lamna Cuvier, 1816, have been reinterpreted using a preliminary identification key for extant Lamniformes based on rostral morphology. In addition, the fossil rostral nodes have been compared in detail with Recent material of both the porbeagle, Lamna nasus (Bonnaterre, 1788) and the salmon shark, Lamna ditropis Hubbs and Follet, 1947. Despite the fact that the rostra compared relatively well with those of Recent Lamna, the Lee Creek Mine specimens proved to differ significantly in having near-parallel lateral rostral cartilages that join the rostral node individually, instead of abutting ones. Based on this observation, we here propose to strike the genus Lamna from the Lee Creek Mine faunal list, so long as no other diagnostic material is forthcoming. These partially preserved rostra are likely to have belonged to extinct taxa within the families Lamnidae or Otodontidae, both of which have been documented from the Yorktown Formation on the basis of isolated teeth of at least three species, Cosmopolitodus hastalis (Agassiz, 1838), Megaselachus megalodon (Agassiz, 1835) and Parotodus benedenii (Le Hon, 1871). |
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