Eocyclotosaurus appetolatus, a Middle Triassic amphibian: Osteology, life history, and paleobiology by L. F. Rinehart and S. G. Lucas. New Mexico Museum of Natural History and Science, Bulletin 70: 1-118. 2016.
This 97-page volume presents a complete analysis of the taphonomy, composition and paleobiology of a Late Triassic bonebed, including a large population sample of the temnospondyl amphibian Koskinonodon. If you are interested in ordering Bulletin 70, it costs $20 and you can contact Beth Ricker, Store Manager for the NMMNH&S, at beth@ naturalhistoryfoundation.org to place orders.
Abstract—Eocyclotosaurus appetolatus is a recently named Middle Triassic (Perovkan: early Anisian) amphibian (Temnospondyli: Capitosauroidea: Cyclotosauridae) from the Moenkopi Formation of New Mexico. Here, we study a population of these animals from a single locality, the Tecolotito bonebed in San Miguel County, north-central New Mexico. This sample provides the first nearly complete postcranial skeletal material of E. appetolatus to be described and illustrated. This disarticulated, attritional assemblage reflects an all-adult population comprising animals in the 1.2 to 2.5 meter length range, and averaging 1.7 meters. The body proportions, and skull and jaw morphology of E. appetolatus was alligator-like, implying that they filled an ecological niche similar to that of some modern crocodilians. Our functional morphology study shows that they were generalist feeders; they probably took fish in the lakes and rivers that they inhabited and small- to medium-sized prey along the shorelines. Data indicate that juveniles grew quickly to sexual maturity in three to four years, after which their growth rate continuously slowed until death. Survivorship analysis indicates that mortality was probably high in the juveniles, was very low in mid-life, and continuously increased in old age. Very few individuals reached the ultimate age of perhaps 30 to 40 years. Based on limb bone allometry and stress-strength analysis, juveniles probably had significant terrestrial capability, allowing dispersal of the species, whereas the adults likely formed breeding populations that became increasingly water-bound. Well-preserved otic regions in some skulls allowed us to determine that impedance matching in the middle ear was excellent, but the high mass of the stapes and large area of the tympanum may have limited hearing to the low end of the audio spectrum, probably extending into the infrasound region.