The Northernmost record of the goose genus Chloephaga (1 Viewer)

[Fred Ruhe]

Gerardo P. Álvarez-Herrera, Federico L. Agnolin, Cecilia Mendez, Carlos Luna, Pedro Cuaranta, Silvina Contreras & Alfredo E. Zunta, 2022

The Northernmost record of the goose genus Chloephaga (Eyton, 1838) (Aves, Anatidae) and its biogeographical implications

Journal of South American Earth Sciences: Article 103988. doi:10.1016/j.jsaAbstrat: mes.2022.103988

Abstract: The Northernmost record of the goose genus Chloephaga (Eyton, 1838) (Aves, Anatidae) and its biogeographical implications

The aim of the present contribution is to describe a partial coracoid (CTES-PZ 7797) coming from Upper Pleistocene Toropí/Yupoí Formation, in Corrientes province, Argentina. The comparative anatomical analysis indicates that it belongs to an indeterminate species of the goose genus Chloephaga, but sharing some characters with the living C. picta. Today, members of this genus breed in Southern Patagonia and migrate to southern Buenos Aires province during the winter season, being its northernmost record 700 km far south from the fossil specimen here reported. The presence of Chloephaga farther north from its current geographical distribution is congruent with the presence in Upper Pleistocene outcrops in the area of mammals that are adapted to arid environments. This constitutes another taxon recorded at Arroyo Toropí that currently presents a different geographic distribution, such as observed in Leopardus pardalis, Chaetophractus villosus, Boa constrictor, Dolichotis patagonica, among other, and shed light on the complex palaeobiogeographic scenario that could have developed during the MIS 5 in the Mesopotamian region of Argentina.

Enjoy,

Fred

 

[Fred Ruhe]

Systematic Paleontolousy

Aves Linneus, 1758
Anseriformes Wagler, 1831
Anatidae Leach, 1820
Anserinae Vigors, 1825
Chloephaga Eyton, 1838
Chloephaga sp.

Referred material. CTES-PZ 7797, small half of a right coracoid, from scapular cotyla to the acrocoracoidal process with an eroded ventral edge

Fred


Figure 1. Comparison between CTES-PZ 7797 (A; F; K; L; M; P) and the extant Chloephaga species: C. picta (CFA-OR - 1597, B; G; N; Q); C. poliocephala (MACN-OR 68401, C; H; O; R); C. rubidiceps (MACN-OR 4978, D; I); and Oressochen melanopterus (E; J). A-E are shown in dorsal view, F-J in ventral view. K-R are details of the cranial end, where K is in lateral view, L in dorso-medial view, M-O in medial view, and P-R in dorsolateral view. P is the graphic representation of L, made for a more detailed anatomical comparison.. Abbreviations: acp: acrocoraocoid process; bt: brachial tubercle; f: foramina; ff: furcular facet; hf: humeral facet; ila: impressio ligamentum acrocoracohumeralis, lta: lateral tubercle of the acrocoracoid process, mas: muscle attachment scar, n: notch, pcp: procoracoid process, ria: recessus infra-acrocoracoideus, sc: scapular cotyla, toc: triosseal canal. The blue shade represent the impressio ligamentum acrocoracohumeralis, limited by divergent crests. Both scale bars equals 1 cm, the lower one applies only to the third row. The last row is not to scale.