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| Patagopipa corsolinii
Rolando, Agnolin & Corsolini, 2019
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Abstract
The aim of the present contribution is to describe a new genus and species of Pipoidea from the Huitrera Formation (Eocene) from Patagonia, Argentina. The new genus shows a unique combination of characters indicating that it is a valid taxon different from other pipimorphs, including the coeval Llankibatrachus truebae. The phylogenetic analysis resulted in the nesting of the new taxon within a previously unrecognized endemic clade of South American aglossans. This new clade turns out to be the sister-group of crown-group Pipidae. This phylogenetic proposal reinforces the hypothesis sustaining the dispersal of pipids between Africa and South America through an island chain or a continental bridge across the Atlantic Ocean by Early Tertiary times.
Keywords: Panpipidae, South America, Argentina, Paleogene, Island chain
Systematic paleontology:
Anura Rafinesque, 1815
Pipoidea Fitzinger, 1843
Panpipidae nomen novum.
Diagnosis. The anuran clade is diagnosed based on the following synapomorphies: 1) anterior ramus of pterygoid dorsally located with respect to the maxilla (23-1); 2) straight distal margin of sacral diapophyses (99-1); 3) cleithrum covering posterior edge of suprascapular cartilage (114-1); 4) interiliac scar ample both ventrally and dorsally (149-2); and 5) presence of a poorly-developed lateral flange on pterygoid (167-1).
Definition. Stem-based clade consisting of Patagopipa and all species that share a more common ancestor with Shelania laurenti, Pipa, and Xenopus laevis than with Vulcanobatrachus mandelai, Avitabatrachus uliana, Cordicephalus gracilis, or Paleobatrachus grandipes.
Remarks. The clade Panpipidae is here coined with the aim to include the crown-group Pipidae, Shelaniinae, and another stem pipids. We follow previous authors (Gómez, 2016, Ford and Cannatella, 1993) in the restriction of Pipidae to crown group taxa; this is Pipinae + Xenopodinae.
Shelaniinae nomen novum.
Diagnosis. This clade is diagnosed based on the following synapomorphies: 1) anterior ramus of pterygoid reaching the antorbital plane (24-1); 2) eight presacral vertebrae (82-1); 3) presacral vertebrae I–II not fused but imbricated medially (88-1); 4) marked forward orientation of the transverse process of presacra vertebrae IV (94-2); 5) cross-section of distal iliac shaft flattened, dorsoventrally compressed (137-2); 6) second pair of ribs anterolaterally oriented (174-1).
Definition. The stem-based clade consisting of Patagopipa and all species that share a more common ancestor with Shelania laurenti than with Pipa, Silurana, Xenopus, or Eoxenopoides.
Included taxa. Shelania pascuali Casamiquela, 1960; Saltenia ibanezi Reig, 1959; Kuruleufenia xenopoides Gómez, 2016; Patagopipa corsolinii nov.
Temporal distribution. From Late Cretaceous to Eocene (probably Pleistocene; Báez et al., 2007) times.
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| Holotype specimen of Patagopipa corsolinii (MLG 2630) in dorsal view. |
Patagopipa nov. gen.
Diagnosis. Small pipoid frog diagnosable based on the following combination of characters (autapomorphies marked by an asterisk): 1) elongate and transversely narrow pterygoids, with poorly expanded proximal flanges*; 2) frontoparietal dorsally flat with rounded anterior and posterior margins; 3) frontoparietal lacking interorbital constriction; and 4) notably robust and stout radioulna and humerus*.
Etymology. Patago, from Patagonia the region of Argentina in which the holotype specimen was found; Pipa, the type genus of the Pipidae family.
Type species. Patagopipa corsolinii nov. sp.
Patagopipa corsolinii nov. sp.
Holotype. MLG 2630, a single slab containing a nearly complete skeleton having partially disarticulated skull, incomplete vertebral column, and nearly complete right fore- and hindlimbs. Left forelimb is poorly preserved, and left hindlimb is only represented by the proximal end of the femur.
Etymology. The specific epithet honors Rodolfo Corsolini, director of the MLG Museum.
Alexis M. Aranciag Rolando, Federico L. Agnolin and Julián Corsolini. 2019. A New Pipoid Frog (Anura, Pipimorpha) from the Paleogene of Patagonia. Paleobiogeographical Implications [Une nouvelle grenouille pipoïde (Anoures, Pipimorpha) du Paléogène de Patagonie. Implications paléobiogéographiques]. Comptes Rendus Palevol. In Press. DOI: 10.1016/j.crpv.2019.04.003
PATAGOPIPA CORSOLINII: UNA NUEVA RANA DE HACE 50 MILLONES DE AÑOS.
Résumé: Le but de cet article est de décrire de nouveaux genre et espèce de Pipioidea de la formation Huitrera (Éocène) de Patagonie, Argentine. Le nouveau genre montre une combinaison unique de caractères indiquant que c’est un taxon valide, différent des autres pipimorphes incluant Llankibatrachus truebae, contemporain. L’analyse phylogénétique résulte en la nidification du nouveau taxon au sein d’un clade endémique, auparavant non reconnu, d’aglosses d’Amérique du Sud. Il en résulte que le nouveau clade est le groupe frère du groupe couronne des Pipidae. Cette proposition phylogénétique renforce l’hypothèse en faveur d’une dispersion des pipidés entre l’Afrique et l’Amérique du Sud au moyen d’une chaîne insulaire ou d’un pont continental à travers l’Océan atlantique au Tertiaire inférieur.
Mots clés: Panpipidae, Amérique du Sud, Argentine, Paléogène, Chaîne insulaire
