albertonykus
Well-known member
Agnolín, F.L., P. Chafrat, and G.P. Álvarez-Herrera (2025)
New specimens of Patagorhacos terrificus Agnolín and Chafrat, 2015 (Aves) shed light on the phylogeny and evolution of the Phorusrhacidae
Historical Biology (advance online publication)
doi: 10.1080/08912963.2025.2458127
Patagorhacos terrificus is a phorusrhacid bird known from the early Miocene of Río Negro province, northern Patagonia. Originally based on the distal end of a quadrate bone, and a referred fragmentary ulna, its affinities were considered dubious by some authors, who also regarded it as Aves incertae sedis. The aim of present contribution is to report two new specimens of Patagorhacos that include valuable anatomical information, including the proximal end of femur, tibiotarsus and proximal and distal end of tarsometatarsus, among others. These new specimens indicate without any doubt that Patagorhacos belongs to phorusrhacid birds, and that it is a valid taxon that can be distinguished from other similar-sized taxa, such as Patagornis and Hermosiornis. With this new information at hand, a new phylogenetic analysis of phorusrhacid birds is performed. This analysis constitutes the most complete dataset known for phorusrhacids (25 taxa and 206 characters) and unambiguously nests Patagorhacos among phorusrhacids. It also lends support to the hypothesis that the loss of flight and acquisition of gigantism among phorusrhacids occurred only once. The North American and European Bathornis and Ameghinornis resulted as the successive sister taxa to Phorusrhacidae, indicating a complex biogeographical scenario.
New specimens of Patagorhacos terrificus Agnolín and Chafrat, 2015 (Aves) shed light on the phylogeny and evolution of the Phorusrhacidae
Historical Biology (advance online publication)
doi: 10.1080/08912963.2025.2458127
Patagorhacos terrificus is a phorusrhacid bird known from the early Miocene of Río Negro province, northern Patagonia. Originally based on the distal end of a quadrate bone, and a referred fragmentary ulna, its affinities were considered dubious by some authors, who also regarded it as Aves incertae sedis. The aim of present contribution is to report two new specimens of Patagorhacos that include valuable anatomical information, including the proximal end of femur, tibiotarsus and proximal and distal end of tarsometatarsus, among others. These new specimens indicate without any doubt that Patagorhacos belongs to phorusrhacid birds, and that it is a valid taxon that can be distinguished from other similar-sized taxa, such as Patagornis and Hermosiornis. With this new information at hand, a new phylogenetic analysis of phorusrhacid birds is performed. This analysis constitutes the most complete dataset known for phorusrhacids (25 taxa and 206 characters) and unambiguously nests Patagorhacos among phorusrhacids. It also lends support to the hypothesis that the loss of flight and acquisition of gigantism among phorusrhacids occurred only once. The North American and European Bathornis and Ameghinornis resulted as the successive sister taxa to Phorusrhacidae, indicating a complex biogeographical scenario.
