Unexpected diversity of ratites (Aves,Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications

Agnolin, F.L., July 2016. Unexpected diversity of ratites (Aves, Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications. Alcheringa 41, xxx–xxx. ISSN 0311-5518.

Ratitae is represented in South America exclusively by Rheidae. Recently, the oldest purported fossil rheid, Diogenornis fragilis, was attributed by several authors to various other ratite clades. A new revision of museum fossil specimens from Argentina has resulted in the discovery of several ratite specimens that clearly do not belong to Rheidae, but resemble other clades. The newly identified specimens derive from Paleogene and Miocene strata. The great diversity of non-rheid Patagonian ratites ended via extinction of several groups by the late Miocene, probably owing to enhanced aridity that also favoured the dispersal of arid-adapted rheids. The new specimens described here reinforce the hypothesis that the traditional vicariant biogeographical model, which proposes ratite clades originated exclusively before the breakup of the Gondwana supercontinent, is questionable owing to the unexpected diversity of various ratite clades in South America, and also in Europe and Africa. This might indicate that the history of Ratitae was more complex than previously envisioned.

Federico L. Agnolin* [fedeagnolin@yahoo.com.ar], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Ángel Gallardo, 470 (1405), Buenos Aires, Argentina. *Also affiliated with: Fundación de Historia Natural ‘Félix de Azara’, Departamento de Ciencias Naturales y Antropología, Universidad Maimónides, Hidalgo 775 (C1405BDB) Ciudad Autónoma de Buenos Aires, República Argentina.     

Phylogenetic analysis of the Panochthini (Xenarthra,Glyptodontidae), with remarks on their temporal distribution

Zamorano, M. & Brandoni, D., 2013. Phylogenetic analysis of the Panochthini (Xenarthra, Glyptodontidae), with remarks on their temporal distribution. Alcheringa 37, 1–10. ISSN 0311-5518.

To test the monophyly of Panochthini, a phylogenetic analysis including all the species traditionally referred to the tribe was conducted. The matrix included 16 species of Glyptodontidae and 35 characters, from which 14 correspond to the skull, four to the dentition, two to the cephalic armour, nine to the dorsal carapace and six to the caudal sheath. Propalaehoplophorus australis (Propalaehoplophorinae) was used to root the trees. Four most parsimonious trees were obtained (Tree Length = 75, CI = 0.65, RI = 0.70). The strict consensus tree (Tree Length = 77, CI = 0.64, RI = 0.68) has the following topology: Propalaehoplophorus australis (Glyptodon reticulatus (Hoplophorus euphractus (Panochthus jaguaribensis, P. intermedius (P. frenzelianus, P. tuberculatus (P. subintemedius, P. greslebini)))) ((Pseudoplohophorus absolutus, Plohophorus figuratus) (Nopachtus cabrerai, N. coagmentatus, Propanochthus bullifer, Stromaphorus compressidens, Phlyctaenopyga ameghini))). The results indicate that: 1, Panochthini is not a natural group but polyphyletic; 2, Panochthus is monophyletic and, concordant with recent proposals, Hoplophorus euphractus is its sister group; and 3, Nopachtus and Propanochthus are more closely related to species traditionally referred to ‘Plohophorini’ than to Panochthus. Nopachtus and Propanochthus, as the ‘Plohophorini’, are recorded from the latest part of the Neogene, whereas Panochthus and Hoplophorus euphractus are restricted to the Quaternary.

[Martín Zamorano [marzamorano@fcnym]unlp.edu.ar], Departamento Científico Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque, s/n, 1900, La Plata, Buenos Aires, Argentina. CONICET. Diego Brandoni [dbrandoni@cicyttp.org.ar], Laboratorio de Paleontología de Vertebrados, Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción (CICYTTP-CONICET), Matteri y España, E3105BWA Diamante, Entre Ríos, Argentina. Received 25.10.2012; revised 11.1.2013; accepted 18.1.2013.     

Palaeoenvironmental implications of the giant crocodylian Mourasuchus (Alligatoridae,Caimaninae) in the Yecua Formation (late Miocene) of Bolivia

Tineo, D.E., Bona, P., Pérez, L.M., Vergani, G.D., González, G., Poiré, D.G., Gasparini, Z.N. & Legarreta, P., 1.10.2014. Palaeoenvironmental implications of the giant crocodylian Mourasuchus (Alligatoridae, Caimaninae) in the Yecua Formation (late Miocene) of Bolivia. Alcheringa 39, xxx–xxx. ISSN 0311-5518

Outcrops of the Yecua Formation (late Miocene) are exposed for approximately 230 m along the La Angostura section of the Piraí River (50 km southwest of Santa Cruz de la Sierra). These reveal massive (argillic palaeosols) and laminated (quiet-water lacustrine and marsh settings) mudstones interbedded with thin sandstones containing microfossils, molluscs and vertebrate remains. Significantly, the succession hosts a giant crocodylian, Mourasuchus (Alligatoridae, Caimaninae), which is represented by both skull and postcranial fragments found in association with freshwater turtles and fishes. Mourasuchus was distributed widely from the middle Miocene of Colombia to upper Miocene of Venezuela, Brazil and Argentina, suggesting connections between major fluvial systems and an active mechanism for dispersal of South American freshwater vertebrates during the Miocene.

David Eric Tineo [tineo.d.e@gmail.com] and Daniel Gustavo Poiré [dgpoire@yahoo.com.ar], CONICET—Centro de Investigaciones Geológicas, Universidad Nacional de La Plata. Calle 1 (644), B1900FWA, La Plata, Argentina; Paula Bona [paulabona26@gmail.com] and Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar], CONICET—División Paleontología Vertebrados, Museo de La Plata. Paseo del Bosque s/n, B1900FWA, La Plata, Argentina; Leandro Martín Pérez [pilosaperez@gmail.com] CONICET—División Paleozoología Invertebrados, Museo de La Plata. Paseo del Bosque s/n, B1900FWA, La Plata, Argentina; Gustavo Dardo Vergani [gvergani@pluspetrol.net]—Pluspetrol S.A. Lima (339), C1073AAG, Ciudad Autónoma de Buenos Aires, Argentina; Gloria González Rigas [ggonzalez@pluspetrol.net]—Pluspetrol Bolivia Corporation SA, Av. Grigotá esq. Las Palmas, Santa Cruz de la Sierra, Bolivia; Pablo Legarreta [plegarreta@pluspetrol.net]—Pluspetrol S.A. Lima (339), C1073AAG, Ciudad Autónoma de Buenos Aires, Argentina.