Main » 2008 » July » 9 » GEORGENTHALIA CLAVINASICA, A NEW GENUS AND SPECIES OF DISSOROPHOID TEMNOSPONDYL FROM THE EARLY PERMIAN OF GERMANY
GEORGENTHALIA CLAVINASICA, A NEW GENUS AND SPECIES OF DISSOROPHOID TEMNOSPONDYL FROM THE EARLY PERMIAN OF GERMANY
Georgenthalia clavinasica, a new genus and species of amphibamid dissorophoid temnospondyl, is represented by a small, complete, postmetamorphic skull from the Lower Permian Bromacker locality, Germany. It is only the third non-amniote of an assemblage of 12 terrestrial tetrapod taxa known from this locality. It is characterized by a broadly rounded skull with large orbits, a short postorbital length, and a unique keyhole-shaped external naris superficially resembling that of trematopid dissorophoids. New features that help to discriminate between amphibamid species are highlighted. Phylogenetically informative characters present in G. clavinasica include: anterolateral flaring of the lateral margin of frontals; narrow interorbital width; ventral orbital process of the prefrontal contacts palatine; palatine exposed on lateral surface of ventral rim of orbit; large otic notches closely approach the orbits; absence of a supratympanic flange of otic notch; long supratympanic process of squamosal with flange-like process that underlaps the midcentral portion of supratemporal. Several features support a highly terrestrial habitus of G. clavinasica, which is consistent with the interpretation of the fossiliferous beds of the Bromacker quarry as representing an upland terrestrial environment in which limnic conditions were characterized by ephemeral lakes and ponds.
Georgenthalia clavinasica, gen. et sp. nov., holotype MNG 11135 in dorsal view. A, interpretive drawing, B, sutures and homologies, C, reconstruction. Grey dots on B indicate centers of dermal ornamentation radiation and, presumably, ossification.
A new clade, Olsoniformes, is named for Dissorophidae and Trematopidae (dissorophoids exclusive of Amphibamidae), and new phylogenetic definitions for Amphibamidae, Trematopidae, and Dissorophidae are presented. The small neotenic Micromelerpetontidae, and presumably also the neotenic and larval Branchiosauridae, fall within the newly defined clade Amphibamidae in the current study, and future work should focus on clarifying the nature of this relationship.
Amphibamids. A, Doleserpeton, modified from Bolt (1969); B, Tersomius, modified from Carroll (1964); C, Micropholis (broad-headed morph), modified from Schoch and Rubidge (2005); D, Eoscopus, modified from Daly (1994).