DISMANTLING THE TRACHINOIDEI - EVIDENCE OF A SCORPAENOID RELATIONSHIPFOR THE CHAMPSODONTIDAE

An examination of the osteology and myology of the Champsodontidae rev eals a number of apomorphic features (e.g., double-headed palatine, la rge pelvic radial, epaxial muscle inserting on the medial pelvic-fin r ay, posterior levator internus inserting on the third epibranchial). T he evidence for a Champsodontidae/Chiasmodontidae relationship is exam ined through a re-evaluation of the basal characters used to define th e suborder Trachinoidei. The Champsodontidae are removed from the Trac hinoidei and a chiasmodontid sister relationship is rejected. After in vestigation of several possible alternative relationships (Paracanthop terygii, Gobioidei, Callionymoidei, Kurtoidei, Apogonidae, Blennioidei , Trichodontidae), champsodontids are hypothesized to be members of th e perciform suborder Scorpaenoidei. This hypothesis is based largely o n the synapomorphy of a parietal spine with an opening for passage of the supratemporal sensory canal, a unique condition of champsodontids and some scorpaenoids. A shared Type 1 epaxial muscle morphology, with separate fibre insertions on the distal tips of the spine-bearing dor sal-fin pterygiophores, is unusual and probably derived among percifor ms. Champsodontids also share with some scorpaenoids Type 5 spinoid sc ales and the origin of Baudelot's ligament from the first vertebra rat her than the basi-occipital, although neither of these features is uni que to these taxa. The occurrence of an enclosed sensory canal on the parietals of Trichodontidae suggest that their relationships might als o lie with the Scorpaenoidei. Arguments pertaining to the removal of c hampsodontids from the trachinoids apply equally to the hypothesized m embership of the Cheimarrichthyidae, Pinguipedidae, Percophididae, Tri chonotidae, Creediidae, Chiasmodontidae, and notothenioids in the Trac hinoidei. Inclusion of these taxa within the Trachinoidei is not well- supported, and their relationships require further investigation.