A new petrel (Aves: Procellariidae) from the early Miocene of Patagonia (Argentina)

ABSTRACT

A right carpometacarpus (MLP 10-XII-11-1) from the early Miocene Gaiman Formation was collected in the fossiliferous locality Bryn Gwyn (Chubut Province, Argentina). After extensive comparisons with extinct and extant species, and geometric morphometric analyses, we concluded that it belongs to Procellariidae. It is supported by the presence of sulcus tendineus restricted to the distal half, a small crest belonging to the m. ulnometacarpalis dorsalis scar, notch and tubercle on the ventral rim of trochlea carpalis, a wide fovea carpalis caudalis not proximally delimited, a rounded, shallow, and proximo-cranial fossa supratrochlearis, and pneumatic foramina within the small fovea carpalis caudalis. The geometric morphometric analyses show clear similarities with Procellariidae, and locate MLP-10-XII-11-1 close to Procellaria aequinoctialis, Daption capense and Pterodroma incerta in the dorsal configuration, and to P. incerta and Macronectes giganteus in the ventral one. Also, the dorsal configuration is more conservative within families than the ventral one. Although this carpometacarpus does not present any exclusive character, the combination of characters found in the new fossil is unique, suggesting that MLP 10-XII-11-1 might represent a new genus and species. However, the proposal of a new species must wait until more complete specimens are found.

Graphical abstract

KEYWORDS:

• Procellariiformes
• carpometacarpus
• geometric morphometric
• principal component analysis
• south America
• neogene

Acknowledgments

We thank the curators Luciano Segura and Diego Montalti (Sección Ornitología, División Zoología Vertebrados) and Mariana Picasso (División Paleontología Vertebrados) from the Museo de La Plata, Yolanda Davies (Colección Ornitológica, Museo Argentino de Ciencias Naturales), Sergio Bogan (Fundación Azara), and Washington Jones (Museo Nacional de Historia Natural). We appreciate the comments of the three anonymous reviewers who contributed in improving the present contribution and the editor G. Dyke.

Disclosure statement

No potential conflict of interest was reported by the authors.