THE GALLINA WELL LOCALITY, AN EARLY PERMIAN (MIDDLE WOLFCAMPIAN) VERTEBRATE AND TRACE FOSSIL SITE IN SOCORRO COUNTY, NEW MEXICO

The Gallina Well locality, first discovered by David S Berman in 1980, is an Early Permian (middle Wolfcampian) vertebrate body and trace fossil site located approximately 20 km northeast of Socorro, New Mexico in the Joyita uplift. The locality is situated stratigraphically low in the Lower Permian Scholle Member of the Abo Formation and is likely Coyotean in age. The fossiliferous bed is a reddish-brown, fluvially-deposited, calcrete-pebble conglomerate. Renewed collecting at the Gallina Well locality in recent years has yielded substantial additions to both the body fossil and the ichnofossil assemblage of the locality. Vertebrate body fossils from the site include a skull fragment of the lepospondyl Diplocaulus, remains of the temnospondyl amphibians Zatrachys sp. and Trimerorachis sp., a partial captorhinid skull and postcranial skeleton, palaeoniscoid fish fossils, postcrania of the diadectomorph Diadectes sp., and specimens of the sphenacodontid eupelycosaurs Sphenacodon and Dimetrodon. A recently recognized coprolite ichno-assemblage includes the first occurrence of Dakyronocopros arroyoensis in New Mexico, the earliest occurrence of Alococopros triassicus as well as records of Heteropolacopros texaniensis and amorphous coprolites. The Gallina Well locality yields the most diverse and extensive vertebrate body fossil assemblage of Early Permian age known from southern New Mexico. Yet, its basic composition differs little from the sphenacodontid-dominated assemblages found to the north, indicating some uniformity of the Coyotean vertebrate fauna across New Mexico.