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Most Ceratodus specimens from the Aptian/Albian of north Texas belong to a small species that is characterized by distinctive sharp dental crests, denticulate in unworn tooth plates. These blade-like crests, indicative of a cutting and chopping dentition, distinguish this lineage from the crushing dentitions of most other North American Cretaceous dipnoans. This species is described and named herein as Ceratodus texanus. The functional adaptation of the dentition of this species (cutting/chopping) is indicative of predation on small invertebrates. The species is recorded from the Antlers Formation at Butler Farm (Wise County) and Greenwood Canyon (Montague County), and from the Twin Mountains Formation at the Jones Ranch Locality (Hood County). Although the natural history of dipnoans in the eastern North American subcontinent remains largely unknown, it is now certain that eastern lungfish populations, after formation of the central seaway, included lineages with crushing dentitions and lineages with sectorial dentitions. [ABSTRACT FROM AUTHOR]

A significant number of lungfish dentitions are now known from the Cretaceous (Cenomanian) Woodbine Formation, primarily from one new locality, the Arlington Archosaur Site of northeast Tarrant County, Texas. The Arlington Archosaur Site preserves a diverse coastal ecosystem within the interbedded coals, mudstones and sand lenses of a delta plain environment. The new lungfish specimens pertain to previously undescribed species from the Cenomanian. Previously recorded from but one specimen, this taxon is now represented by both prearticular and pterygopalatine dental plates of sectorial aspect. This species is similar to, and presumably descended from, one that has been previously recorded from various formations of Albian age. Measurements of the angles of the dental plate margins and crests confirm that it is distinct. Two small specimens appear to represent an earlier ontogenetic stage. Although dipnoan evolution generally appears to have proceeded slowly, the taxa from the Cretaceous (Albian -- Cenomanian) of Texas may possibly provide some stratigraphic indices, based on what is now known. The new Woodbine lungfish is herein referred to a new species; Ceratodus carteri. [ABSTRACT FROM AUTHOR]