Holotype.—Right humerus lacking the ventral tubercle, portions of the pectoral crest, and other parts of the proximal end, where partially reconstructed, NJSM 11341.
Locality and Horizon.—Main fossiliferous layer of the Inversand Company marl pit, Sewell, Gloucester County, New Jersey; basal portion of the Hornerstown Formation, latest Cretaceous (Maastrichtian); collected 11 October 1973 by David C. Parris.
Measurements of Holotype (in mm).—Length as reconstructed, 110; width and depth of shaft at midpoint 7.0 × 5.6; distal width 14.8; depth through dorsal condyle 8.7.
Etymology.—From Latin, glaucus (Greek, glaukos), bluish green or gray, sea-colored, applied to greensands because of their color, although appropriate because of their marine origins as well; in reference to the holotype having been recovered from beds of glauconite.
Remarks.—A possible relationship between the Procellariiformes and Pelecaniformes has been previously suggested (Sibley and Ahlquist, 1972:70; Olson, 1985:142), and among the pelecaniform taxa most often mentioned as being procellariiform-like are the Fregatidae. It is tempting to regard the humerus of Tytthostonyx as being similar to that possessed by the ancestral stock that gave rise to the Procellariiformes. Its similarities also to the Eocene frigatebird Limnofregata would thus be seen as corroborating the primitiveness of the Fregatidae within the Pelecaniformes. Whereas Tytthostonyx definitely has not achieved the highly distinctive and presumably derived morphology of the humerus of modern Procellariiformes, the incipient development of the ectepicondylar spur and deep brachial depression could be interpreted as tending in that direction.
On the other hand, we must admit that we are dealing with only a single bone and one of very great age at that, so that the risk of overinterpreting the fossil is correspondingly great. We can only discern the overall similarities of the specimen and phylogenetic inferences can therefore be only tentative at best.
Family and Genus Indeterminate
Figure 9e,f
Referred Material.—Distal portion of left ulna ANSP 15713.
Locality and Horizon.—Inversand Company marl pit, near Sewell, Gloucester County, New Jersey; Hornerstown Formation, Late Cretaceous (Maastrichtian); not found in situ, collected on shelf formed by "blue bed"; collected 31 August 1977 by Richard S. White.