Meeting Abstract
The Cretaceous squamate Coniophis precedens has been put forth as a transitional form between ‘lizards’ and snakes because of an apparent mosaic of derived (snakelike) and plesiomorphic (lizardlike) characteristics. The holotype of Coniophis precedens is a dorsal vertebra. Referred specimens include vertebrae, maxillae, and a dentary; these referrals were based on relative size and stratigraphic occurrence. The referred dentary is snakelike, but the maxillae show no clear snake synapomorphies, leading to the suggestion that ‘snakelike’ characters appeared in the mandible and vertebrae before the maxilla. Because there are no overlapping parts or associated specimens to confirm skull fragment referrals, the original study presented a phylogenetic analysis demonstrating that the individual elements occupy a similar phylogenetic position within Squamata, as basal snakes. Unfortunately, taxon selection from that analysis constrained these specimens to be snakes. When non-snake taxa (including a clupeid fish) were put into that analysis, they also were recovered as basal snakes. I re-examined the specimens and my own broad-scale morphological cladistic analysis of squamates found that the holotype Coniophis precedens vertebra is a basal snake. The dentary was volatile within the tree topology, but may represent a basal snake. The maxillae belong to a ‘necrosaur-grade’ platynotan lizard. Squamate paleontology has a long and continuing history of designating extremely fragmentary holotype specimens. Complete fossil skeletons or body fossils are extremely rare, especially for terrestrial taxa, so designation of incomplete holotypes is a necessity. Even so, there must be a limit to what is acceptable based on the utility of a given specimen as a name holder. I propose a basic conditional system for assessing specimen usefulness as a holotype.
