Dryornis hatcheri sp. nov. (1 Viewer)

[albertonykus]

Degrange, F.J. (2022)
A new species of Dryornis (Aves, Cathartiformes) from the Santa Cruz Formation (lower Miocene), Patagonia, Argentina
Journal of Vertebrate Paleontology (advance online publication)
doi: 10.1080/02724634.2021.2008411

No abstract, first paragraph of the introduction is copied below:

The Santa Cruz Formation (lower Miocene) has one of the richest fossil assemblages in South America (Vizcaíno et al., 2012). Fossils were first collected in the  19th century, when the expeditions carried out by Francisco P. Moreno and Carlos Ameghino resulted in the discovery of different species, mainly mammals. This Cenozoic fauna caught the attention of William B. Scott of Princeton University (U.S.A.) who trusted John B. Hatcher to lead the expeditions to Patagonia between 1896 and 1899. Hatcher visited different localities in the Santa Cruz province, mainly on the Atlantic coast, spending less time in the outcrops along the Santa Cruz River and in the Andean region (Fernícola et al., 2019). After collecting a large amount of specimens, he returned to the U.S.A., where the material was deposited in the paleontological collections of the Peabody Museum (New Haven) and the American Museum of Natural History (New York). Taking into account that some of the materials were fragmentary or poorly visited and consulted, the phylogenetic affinities of some of the remains are still a subject of debate.

 

[Fred Ruhe]

SYSTEMATIC PALEONTOLOGY

Class AVES Linnaeus, 1758
Subclass NEOGNATHAE Pycraft, 1900
Order CATHARTIFORMES Coues, 1884
Family CATHARTIDAE Lafresnaye, 1839
Remarks—The presence of a smooth S-shaped shaft when viewed laterally, with the extremitas distalis humeri strongly deflected cranially, a triangular fossa musculibrachialis extended mediodistally, and a well-developed quadrangular epicondylus dorsalis permits the assignation of the specimen YMP-PVVU
15866 to Cathartidae.

Genus DRYORNIS Moreno and Mercerat, 1891

Type Species—Dryornis pampeanus Moreno and Mercerat, 1891

Amended Diagnosis—Dryornis corresponds to medium to giant-sized Cathartidae characterized by having the extremitas distalis humeri strongly deflected cranially. The fossa musculi brachialis is poorly extended laterally and endowed with a marked elliptical scar, not bounded distally by a stout bridge.

DRYORNIS HATCHERI sp. nov.

Holotype—Left fragmentary humerus, YMP-PVVU 15866.

Etymology—Honoring John B. Hatcher, who collected the fossil and whose expeditions to Patagonia between 1896 and 1899 resulted in prolific knowledge and a number of publications on the santacrucian fauna.

Occurrence—Lago Pueyrredón, Santa Cruz Province, Argentina, Santacrucian (early Miocene). See Cuitiño et al. (2019) for an extensive description of the geological setting.

Diagnosis—A medium-sized cathartid vulture. Humerus with smooth S-shape shaft when viewed laterally; fossa m. brachialis triangular and extended mediodistally; presence of elliptical scar on the fossa m. brachialis (quite similar to that of Dryornis pampeanus, although deeper and located more laterally*); sulcus humerotricipitalis shallow and pneumatized*; incisura intercondylaris narrow*. * indicate features exclusive to D. hatcheri and not present in other species of Dryornis.


FIGURE 1. Holotype of Dryornis hatcheri in A, cranial, caudal, ventral and dorsal views; B, detail of the extremitas distalis humeri in cranial view.
Abbreviations: cd, condylus dorsalis; cv, condylus ventralis; ed, epicondylus dorsalis; es, elliptical scar of the fossa m. brachialis; ev, epicondylus ventralis;
fmb, fossa musculi brachialis; fo, fossa olecrani; ii, incisura intercondylaris; sht, sulcus humerotricipitalis; sst, sulcus scapulotricipitalis. Scale bar
equals 1 cm.

Fred