A Review of the Palaeobiology of Some Neogene Sharks and the Fossil Record of Extant Shark Species

Abstract

In the last years, new findings and new methods (stable isotopes of oxygen, zinc and nitrogen, 2D and 3D modelling, geometric morphometric analyses of the teeth) have enhanced our knowledge of the Neogene shark fauna and its palaeobiology. Several papers deal with the large Otodus (Megselachus) species, including the construction of a 3D model as well as insights into lifestyle and diet. In addition, skeletal remains of Carcharias gustrowensis, Carcharodon hastalis, Keasius parvus and a natural tooth set of Carcharodon hubbelli have been described in the last 13 years, and the dentition of the Neogene species Carcharoides catticus, Megachasma applegatei and Parotodus benedenii have been reconstructed. 
 Stable isotope analyses of the teeth from the Neogene species of Araloselachus, Carcharias, Carcharodon, Galeocerdo, Hemipristris, and Mitsukurina have given insights into the trophic position of these genera during the Neogene, and shark teeth preserved near skeletal remains of prey animals (mammals) and shark bite traces on these remains provide direct evidence of trophic interactions. Tooth shape, fossil locality and palaeoenvironment have been used to better understand the taxa Carcharhinus dicelmai, Megalolamna paradoxodon, Pachyscyllium dachiardii and P. distans.
 Among extant species, Galeorhinus galeus can be traced back to the Eocene. The following taxa can be traced back to the Oligocene: ?Alopias superciliosus, and Rhincodon typus. Species already present in the Miocene include: Alopias vulpinus, Carcharhinus amblyrhynchoides, C. amblyrhynchos, C. albimarginatus, C. amboinensis, C. brachyurus, C. brevipinna, C. falciformis, C. glaucus, C. leucas, C. limbatus, C. longimanus, C. macloti, C. obscurus, C. perezi, C. sealei, ?Carcharodon carcharias, Centrophorus granulosus, Cetorhinus maximus, Dalatias licha, Deania calcea, Galeocerdo cuvier, , Glyphis glyphis, Heptranchias perlo, Isurus paucus, Lamna nasus, Negaprion brevirostris, Odontaspis ferox, Pseudocarcharias kamoharai, Sphyrna media, S. mokarran. First appearing in the Pliocene are: Scymnodon ringens, Somniosus rostratus, Zameus squamulosus. For some extant species (Carcharias taurus, Hexanchus griseus, Isurus oxyrinchus, Notorynchus cepedianus, Sphyrna zygaena) it is not clear if the assigned Neogene teeth represent the same species. Applying these new methods to more fossil shark taxa, a detailed search for shark fossils, as well as better knowledge of the dentition of extant species (especially those with minute-sized teeth) will further enhance knowledge of the evolution and palaeobiology of sharks.