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Eight fossil tetrapod footprints from lake-shore deposits in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site (SGDS) in southwestern Utah cannot be assigned to the prevalent dinosaurian (Anomoepus, Eubrontes, Gigandipus, Grallator, Kayentapus) or crocodyliform (Batrachopus) ichnotaxa at the site. The tridactyl and tetradactyl footprints are incomplete, consisting of digit- and digit-tip-only imprints. Seven of the eight are likely pes prints; the remaining specimen is a possible manus print. The pes prints have digit imprint morphologies and similar anterior projections and divarication angles to those of Brasilichnium, an ichnotaxon found primarily in eolian paleoenvironments attributed to eucynodont synapsids. Although their incompleteness prevents clear referral to Brasilichnium, the SGDS tracks nevertheless suggest a eucynodont track maker and thus represent a rare, Early Mesozoic occurrence of such tracks outside of an eolian paleoenvironment. [ABSTRACT FROM AUTHOR]

Abstract: A new specimen of an enantiornithean bird from the Lower Cretaceous Xiagou Formation of Gansu Province, northwestern China, consists of an articulated distal left humerus, ulna, radius, carpus, and [...]

When naming ichnotaxa based on uncollectable trace fossils, the holotype is the actual ichnofossil in the outcrop, though some ichnologists identify the holotype as a replica (cast) held in a museum collection, and refer to it as a "plastotype," although not all such replicas are made from plaster. Nevertheless, through its Code, the International Commission on Zoological Nomenclature (ICZN) makes it clear that an artificial, human-made replica (plaster cast or otherwise) is not eligible to be the holotype of an ichnotaxon. This directive is potentially destabilizing to much ichnological taxonomy, which is based on holotypes left in the field that have disappeared or will disappear. One possible solution for ichnologists will be to petition the ICZN to recognize that artificial, human-made replicas of ichnofossils can serve as name-bearing types. These may best be called "axiotypes" (from the Greek axios, meaning "of equal value"). [ABSTRACT FROM AUTHOR]