The cranial morphology and relationships of the aberrant Carboniferous amphibianSpathicephalus mirusWatson

Abstract

The skull ofSpathicephalus mirusWatson, an amphibian from the Namurian, basal Upper Carboniferous, of Scotland is described. It shares with the Loxommatoidea a closed palate, palatal ornament and antorbital vacuities, and the family Spathicephalidae is recognized as the sister group of the Loxommatidae. A new diagnosis of the Loxommatoidea is presented together with one of the Spathicephalidae. An analysis of the functional morphology of theSpathicephalusskull suggests that it was incapable of rapid jaw closure required for catching fish. Instead it is proposed thatSpathicephaluswas a sluggish bottom-dwelling filter-feeder of small, soft invertebrates.