Scauménellisation de l'Acanthodii Triazeugacanthus affinis (Whiteaves) de la formation d'Escuminac (Dévonien supérieur de Miguasha, Québec) : révision du Scaumenella mesacanthi Graham-Smith

Abstract

Scaumenella mesacanthi (Graham-Smith, 1935) from the Escuminac Formation (Upper Devonian, Miguasha, Quebec) was originally described tentatively as a chordate, probably a vertebrate. It was later variously considered to be a larval ostracoderm or some early form of prochordate, the latter being the commonly accepted interpretation. We present a new description while associating it with the subclass Acanthodii, namely, Triazeugacanthus affinis (Whiteaves). We show that "Scaumenellas" are the remains of T. affinis that have undergone a degradation during fossilization, which we name scaumenellization.