Anserini

Anserini indeterminate

Material. Left carpometacarpus, proximal part, AaO-2663; left phalanx 1 of major digit of wing, AaO-735 (it is not possible to know whether they come from the same individual).

The carpometacarpus shows the morphological characteristics of the Anserini (Woolfenden, 1961) and its size corresponds to the Recent species Branta canadensis, the Canada Goose. Its measurements are (in mm): proximal width, 9.1; proximal depth, 20.8. It is larger than the extinct species Branta woolfendeni, from the upper Miocene or lower Pliocene of Big Sandy Fm. (Bickart, 1990).

On the phalanx the distal portion of the Pila cranialis phalangis is incomplete, mainly on the ventral side. This phalanx differs from that of the Anatinae by its much deeper Fossa ventralis. This Fossa ventralis is more developed in the proximal part of the phalanx. The measurements are (in mm): length (without the distal point), 32.4; proximal width (dorsoventrally), 8.0; proximal depth (craniocaudally), 7.3; maximum depth (craniocaudally) 10.4. As for the carpometacarpus, this phalanx is similar to that of the genus Branta but it is larger than the Recent Branta bernicla. Anserini (genus and species indeterminate) are present in the Pliocene of the Yorktown Formation. They are also comparable in size to Branta canadensis (Olson & Rasmussen, 2001).