Among living families, the Burhinidae are the most similar to Graculavus; both agree in characters 1, 2, 4, and 7, with certain species of Burhinus also having characters 3 and 6 present but less developed. Graculavus differs from Burhinus mainly in having (8) the head not as deep and bulbous; (9) distance from head to tuberculum dorsale greater; (10) tuberculum dorsale smaller, much less projecting; (11) tuberculum ventrale in ventral view more elongate; and (12) scar on tuberculum ventrale for M. coracobrachialis caudalis much larger and more distinct.
Graculavus is very similar to Presbyornis, agreeing with that genus in characters 8 and 10 but differing in characters 11 and 12 and in (13) having the head more deeply undercut. Presbyornis is intermediate between Graculavus and the Burhinidae in character 9.
Graculavus velox was a fairly large bird, being approximately the size of Presbyornis cf. pervetus and somewhat larger than the large living burhinid Esacus magnirostris.
Graculavus velox?
Figure 9d
Referred Material.—Abraded right carpometacarpus consisting mainly of the major metacarpal, NJSM 11854.
Locality and Horizon.—Collected from the main fossiliferous layer of the Inversand Company marl pit, Sewell, Gloucester County, New Jersey; Hornerstown Formation, latest Cretaceous (Maastrichtian); collected 25 February 1976 by David C. Parris.
Measurements (in mm).—Length 51.0.
Comparisons.—Nothing can be said about this very poor specimen except that it came from a bird with a carpometacarpus slightly larger than that of a modern specimen of the burhinid Esacus magnirostris. Because Graculavus velox is the only bird yet known in the New Jersey fossil fauna that was of this same size, the present specimen may possibly be referable to that species.