A new Miocene penguin from Patagonia and a phylogenetic analysis of living and fossil species

ACOSTA HOSPITALECHE, C.; TAMBUSSI, C.; DONATO, MARIANO; COZZUOL, M.

ACTA PALAEONTOLOGICA POLONICA

Instytut Paleobiologii PAN

Año: 2006 vol. 52 p. 1 - 16

0567-7920

We describe a new medium−size penguin (Spheniscifomes), Madrynornis mirandus gen. et sp. nov. from the early late Miocene Puerto Madryn Formation of Chubut Province, Argentina. Although it is evident that extant and fossil penguins constitute a remarkably homogeneous family of birds, their within−group phylogenetic relationships are less obvious. In order to identify the phylogenetic position of the new taxon, we conducted a phylogenetic analysis of 20 taxa (17 repre− sentative species of all living genera and three fossil species belonging) using 44 osteological characters. The family Spheniscidae is clearly monophyletic and Madrynornis mirandus is closely related to the living taxa. Our phylogenetic interpretation is congruent also with biostratigraphic data, with Paraptenodytes from the early Miocene (about 20 Ma) lo− cated at the base of the Spheniscidae. Classically, two basic tarsometatarsal types were recognized (one for pre−Miocene and the other for the post−Miocene penguins), based on the pattern of the proximal foramina and the hypotarsus.Madrynornis mirandus gen. et sp. nov. from the early late Miocene Puerto Madryn Formation of Chubut Province, Argentina. Although it is evident that extant and fossil penguins constitute a remarkably homogeneous family of birds, their within−group phylogenetic relationships are less obvious. In order to identify the phylogenetic position of the new taxon, we conducted a phylogenetic analysis of 20 taxa (17 repre− sentative species of all living genera and three fossil species belonging) using 44 osteological characters. The family Spheniscidae is clearly monophyletic and Madrynornis mirandus is closely related to the living taxa. Our phylogenetic interpretation is congruent also with biostratigraphic data, with Paraptenodytes from the early Miocene (about 20 Ma) lo− cated at the base of the Spheniscidae. Classically, two basic tarsometatarsal types were recognized (one for pre−Miocene and the other for the post−Miocene penguins), based on the pattern of the proximal foramina and the hypotarsus.Madrynornis mirandus is closely related to the living taxa. Our phylogenetic interpretation is congruent also with biostratigraphic data, with Paraptenodytes from the early Miocene (about 20 Ma) lo− cated at the base of the Spheniscidae. Classically, two basic tarsometatarsal types were recognized (one for pre−Miocene and the other for the post−Miocene penguins), based on the pattern of the proximal foramina and the hypotarsus.Paraptenodytes from the early Miocene (about 20 Ma) lo− cated at the base of the Spheniscidae. Classically, two basic tarsometatarsal types were recognized (one for pre−Miocene and the other for the post−Miocene penguins), based on the pattern of the proximal foramina and the hypotarsus. Madrynornis mirandus exhibits an arrangement of the proximal foramina and a degree of metatarsals fusion similar to the living forms, although its elongation index (total length/proximal width)is reminiscent of the extinct Paraptenodytesexhibits an arrangement of the proximal foramina and a degree of metatarsals fusion similar to the living forms, although its elongation index (total length/proximal width)is reminiscent of the extinct ParaptenodytesParaptenodytes (a penguin historically recognized as a pre−Miocene form, coming from the early Miocene of Argentina). Madrynornis re− veals that the two basic tarsometatarsal types co−existed among Miocene penguins.Madrynornis re− veals that the two basic tarsometatarsal types co−existed among Miocene penguins.