Fossil Record 18(1): 73-80, doi: 10.5194/fr-18-73-2015
New specimen of Cacops woehri indicates differences in the ontogenetic trajectories among cacopine dissorophids
expand article infoNadia Froebisch, A. Brar§, R. R. Reisz§
‡ Museum fuer Naturkunde, Berlin, Germany§ Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road N, Mississauga, ON L5L 1C6, Canada
Open Access
Abstract
The Lower Permian Dolese locality has produced numerousexquisitely preserved tetrapod fossils representing members of alowerPermian upland fauna. Therein, at least nine taxa of the cladeDissorophoidea, ranging in size from the large predaceous trematopidAcheloma to the miniaturized amphibamid Doleserpeton, highlight the great taxic and ecologicaldiversity of this anamniote clade. Here we describe a large specimen of thedissorophid Cacops woehri, which was previously only known from the juvenile or subadultholotype skull. Another member of the genus Cacops present at the Dolese locality,Cacops morrisi, is also represented by specimens spanning juvenile, subadult, and adultstages, allowing for a comparison of morphological changes taking place inthe late phases of the ontogenetic trajectory of cacopine dissorophids. Thenew find shows that, in contrast to C. morrisi and C. aspidephorus,C. woehri only undergoes relatively subtlechanges in skull morphology in late ontogeny and retains the overall moregracile morphology into adult stages. This includes retention of the rathershallow skull shape as well as a pattern of sculpturing consisting ofelongate ridges and grooves and a large occipital flange. This suggestssomewhat different functional demands in C. woehri than in other known species ofCacops, possibly associated with a different ecology paralleling the great taxicdiversity of dissorophoids at the Dolese locality.