Taxa from Upper Cretaceous deposits in western North America that appear to fall in the same category (Olson and Feduccia, 1980a) include: Apatornithidae Fürbringer, 1888; Cimolopterygidae Brodkorb, 1963a; Torotigidae Brodkorb, 1963a; and Lonchodytidae Brodkorb, 1963a.
Tertiary taxa that may possibly be related to the "transitional Charadriiformes" and that have been used as the basis of family-group names are: Presbyornithidae Wetmore, 1926 (Nautilornithinae Wetmore, 1926, and Telmabatidae Howard, 1955, are definitely synonyms); Scaniornithidae Lambrecht, 1933; and Dakotornithidae Erickson, 1975.
Doubtless there are others that we have overlooked. How many families are actually represented here and what their interrelationships may be is purely a matter of conjecture in the absence of better fossil material. Because the entire skeleton of Presbyornis is known, the familial name Presbyornithidae may justifiably be retained and used for that genus.
In the case of the Cretaceous birds under consideration here, we have decided for the time being to adopt a version of paleobotanical convention in recognizing a "form family" Graculavidae, which implies a general similarity in morphology of the constituent taxa, although the material available is simply not sufficient for determining phylogeny or key adaptations.
Genus Graculavus Marsh, 1872
Limosavis Shufeldt, 1915:19.
Type-Species.—Graculavus velox Marsh 1872, by subsequent designation (Hay, 1902).
Included Species.—Type species only.
Remarks.—Limosavis Shufeldt, 1915, substitute name for Graculavus, considered inappropriate; not used in direct combination with any specific name when originally proposed.