New anhingid (Aves, Suliformes) from the Middle Miocene of Río Negro Province, Patagonia, Argentina

AGNOLIN, F.; NORIEGA, J.I.; DIEDERLE J.M.

Diamante

Simposio; 9Th International Meeting of the Society of Avian Paleontology and Evolution. Diamante, Argentina; 2016

Centro de Investigaciones Científicas y Transferencia a la Producción

Dartersor snake birds are diving birds of the family Anhingidae that live in tropicaland subtropical climate, mainly in freshwater habitats. In South America thegiant diving anhingidsare one of the most conspicuous faunistic elements of the Miocene avifaunas. However,the anhingid record from Patagonia is still sparse, being composed by Anhinga hesterna (Ameghino 1895) andindeterminated species of the genus Macranhinga,both coming from the late early Miocene of Santa Cruz province, Argentina, and Meganhinga chilensis Alvarenga 1995 fromthe late early Miocene of Malleco province, Chile. The aim of the presentcontribution is to describe a new species of Macranhinga coming from Colloncuran levels of an unnamedstratigrahic unit (middle Miocene) of Southwestern Puesto Marileo, nearIngeniero Jacobacci city, Río Negro province, north-central Patagonia. The newspecies is represented by an incomplete proximal end of tarsometatarsus, distalend of tibiotarsus, and distal end of humerus that differ from other species ofthe genus in a unique combination of characters. It is curious to note thattogether with very large size (more than 50% larger than species of Anhinga) and robustness, South AmericanNeogene anhingids share a number of features that indicate they may belong to amonophyletic clade within Anhingidae. An overview of the anhingid recordsuggests that the purported phororhacoid Pseudolaruseocaenus Ameghino 1895, coming from the Miocene of Santa Cruz province, mayalso belong to Anhingidae. New and old anhingid records from the Miocene ofPatagonia indicate that the family diversity was far more diverse thatcurrently understood, and was possible comparable to that exhibited innortheastern Argentina and Brazil, as for example.