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Trophic niche ontogeny and palaeoecology of early T oarcian S tenopterygius ( R eptilia: I chthyosauria)
Author(s) -
Dick Daniel G.,
Schweigert Günter,
Maxwell Erin E.
Publication year - 2016
Publication title -
palaeontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.69
H-Index - 63
eISSN - 1475-4983
pISSN - 0031-0239
DOI - 10.1111/pala.12232
Subject(s) - ontogeny , biology , niche , paleoecology , trophic level , zoology , ecological niche , evolutionary biology , dentition , ecology , fish <actinopterygii> , sexual maturity , paleontology , habitat , fishery , genetics
Reconstructing ecological niche shifts during ontogeny in extinct animals with no living analogues is difficult without exceptional fossil collections. Here we demonstrate how a previously identified ontogenetic shift in the size and shape of the dentition in the early T oarcian ichthyosaur S tenopterygius quadriscissus accurately predicts a particular dietary shift. The smallest S . quadriscissus fed on small, burst‐swimming fishes, with a steady shift towards faster moving fish and cephalopods with increasing body size. Larger adult specimens appear to have been completely reliant on cephalopods, with fish completely absent from gut contents shortly after onset of sexual maturity. This is consistent with a previously proposed ontogenetic niche shift based on tooth shape and body size, corroborating the idea that dental ontogeny may be a useful predictor of dietary shifts in marine reptiles. Applying the theoretical framework used here to other extinct species will improve the resolution of palaeoecological reconstructions, where appropriate sample sizes exist.