ALBANERPETONTIDAE

Gardner, JD, 2000, Albanerpetontid Amphibians from the Upper Cretaceous (Campanian and Maastrichtian) of North America, Geodiversitas 22 (3), pp. 349-388 : 361

Family ALBANERPETONTIDAE

Fox & Naylor, 1982

Genus Albanerpeton Estes & Hoffstetter, 1976

REMARKS

Elsewhere I have justified my use of the higher level names Allocaudata and Albanerpetontidae (Gardner 1999a) , provided revised diagnoses for the Albanerpetontidae and the type genus Albanerpeton (Gardner 1999d, 2000a), and presented an outline of my hypothesis of relationships within the genus (Gardner 1999b, c). I currently recognize seven species in Albanerpeton . The type species A. inexpectatum Estes & Hoffstetter, 1976 (Miocene, France), A. arthridion Fox & Naylor, 1982 (uppermost Aptianmiddle Albian, Texas and Oklahoma), and A. cifellii Gardner, 1999b (upper Turonian, Utah) have been considered in recent papers by myself (Gardner 1999a, b, d, 2000a, b) and others (McGowan 1998; Rage & Hossini 2000). A fourth species represented by jaws and frontals from the upper Paleocene of Alberta will be formally named and described elsewhere.

Each of the three remaining congeners considered below is known by jaws and frontals, and can be assigned to Albanerpeton based on the following combination of diagnostic frontal character states (Gardner 2000a): fused frontals triangular-shaped in dorsal or ventral outline; internasal process pointed anteriorly in dorsal or ventral outline; ratio of midline length to width across posterior edge between lateral edge of ventrolateral crests about 1.2 or less; lateral face of internasal process bearing elongate groove for tongue-in-groove contact with nasal; anterolateral process prominent and pointed distally; dorsal and ventral edges of slot for receipt of prefrontal excavated medially; anterior end of orbital margin located approximately in line with, or posterior to, anteroposterior midpoint of frontals; and orbital margin uniformly shallowly concave to nearly straight along entire length in dorsal or ventral outline. Elsewhere I (Gardner 2000a: fig. 1) have depicted reconstructed frontals for the three species based on specimens described below. Each species also exhibits two premaxillary synapomorphies — suprapalatal pit low on pars dorsalis and occupying 4% to no more than 25% of lingual area of pars dorsalis — that are unique among albanerpetontids to a subgeneric clade containing all congeners, except A. arthridion (Gardner 1999a, b, c). This unnamed clade consists, in turn, of two less inclusive sister-clades: the robust- and gracile-snouted clades. Each of the species described below belongs to one or the other of these sister-clades.