Rileymillerus
From Wikipedia, the free encyclopedia
| Rileymillerus Temporal range: Late Triassic, | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Temnospondyli |
| Suborder: | †Stereospondyli |
| Superfamily: | †Metoposauroidea |
| Genus: | †Rileymillerus Bolt and Chatterjee, 2000 |
| Type species | |
| †Rileymillerus cosgriffi Bolt and Chatterjee, 2000 | |
Rileymillerus is an extinct genus of temnospondyl amphibian from the Late Triassic Post Quarry in the Dockum Group of Texas that was described by John Bolt and Sankar Chatterjee in 2000.[1] The holotype, a nearly complete skull with articulated jaws, is housed at the Museum of Texas Tech University. The genus is named for Riley Miller, who allowed Chatterjee to work on the Post Quarry, and the species is named for the paleontologist John Cosgriff.
Rileymillerus cosgriffi most closely resembles the poorly-known Latiscopus disjunctus that was described from similarly aged deposits of the Dockum Group near Otis Chalk, Texas.[2] As was noted by Wilson (1948) and Bolt & Chatterjee (2000), both of these taxa differ substantially from the morphology seen in large, flat-skulled aquatic temnospondyls of the Late Triassic (metoposaurids in North America). Examples of their more unusual anatomy (most of which are confidently known only in R. cosgriffi) include the absence of a lacrimal bone, the presence of a lateral exposure of the palatine bone, a tall skull with laterally facing orbits, and an anteromedial inflection of the palatal ramus of the pterygoid. Both are also exceptionally small for Triassic temnospondyls, with skull lengths estimated around 3.5 cm (compared to those of metoposaurids, which exceeded 50 cm), and appear to have been relatively terrestrial (evidenced by an absence of lateral line grooves found in aquatic temnospondyls). Other than the holotype skull, only a few small, isolated, potentially diplospondylous intercentra were referred to R. cosgriffi.
