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We redescribe and interpret the postcranial elements of Allalmeia atalaensisRusconi, found in the Divisadero Largo Formation, Mendoza, Argentina. Allalmeiais one of the few basal notoungulates with preserved postcranial remains. Rusconi initially documented a skull, several vertebrae and part of the appendicular skeleton but these specimens were subsequently lost. Recently though, distal components of the holotype humeri, the proximal portion of the right femur, several broken diaphyses and most of the left and right pes (MCNAM-PV 507), were relocated. Preparation of this material has revealed new details, especially from the plantar side of the feet. The calcaneum has a distal peroneal process with marked rugosity in the lateral end, a well-developed calcaneal plantar tubercle and a large sustentaculum tali. The naviculars exhibit a well-developed medial tuberosity and slightly contact the calcaneum on the dorsal side, a condition called a ‘reverse alternating tarsus’. The disposition and morphology of the cuneiforms are similar to those of more recent typotheres and the archaic ungulate Tetraclaenodon puercensis. The phalangeal rows are oblique to each other, as in some extant digitigrade mammals. The ungual phalanges are claw-like suggesting that they might have borne claws. Long bones are gracile in comparison with other notoungulates, but with well-developed muscle origins and insertions. The use of body-mass allometric equations and a comparison with extant analogues suggests that Allalmeiawas a small, generalized, digitigrade animal. An estimated body mass of approximately 3 kg is consistent with oldfieldthomasiids and archaic ungulates.

The first lungfish tooth plate from the Las Flores Formation, Chubut, southern Argentina, is described. This is the youngest ceratodontid known from the continent. In Africa, ceratodonts disappeared in the Eocene. Afterwards, they are only known from Australia until their extinction during the Pleistocene. The Las Flores tooth plate also represents the southernmost lungfish known since the Coniacian (early Late Cretaceous).

ABSTRACTThe Paleocene locality of Punta Peligro (Hansen Member of the Salamanca Formation) in Argentina has yielded not only ‘condylarths’ but also an extraordinary assemblage of therian mammals derived from Laurasian immigrants and non-therian mammals, relicts of the Mesozoic Gondwanan radiation. The materials, a left jaw fragment with the talonid of the second molar and the third molar, and an isolated upper molar, allow the revalidation of Raulvaccia peligrensisconsidered previously as a junior synonym of Escribania chubutensis. In addition to other characters, Raulvacciastrongly differs from E. chubutensisin its lesser size, the development of the m3 talonid, the presence of a hypocristid, and a postcristid. Originally Raulvacciaand Escribaniawere considered as Mioclaenidae, Kollpaniinae, together with other ungulates from the Santa Lucía Formation, from the early Paleocene locality of Tiupampa in Bolivia. In contrast to the Tiupampan ‘condylarths,’ Raulvacciashares derived characters with E. chubutensis, particularly in the upper molars, such as a strong parastyle and the presence of hypocone located close to, but well differentiated from the protocone. These characters support a previous hypothesis which argues for the removal of the Peligran ‘condylarths’ from the more primitive Kollpaniinae, and sustains its relationship to the exclusively South American Didolodontidae. The revalidation of Raulvaccia peligrensisshows that the diversity of placental mammals during the earliest known Paleocene in Patagonia was greater than previously thought, and supports for the early differentiation of the Didolodontidae.

A new genus and species of Proterotheriidae Megadolodinae, Bounodus enigmaticus, from the Upper Miocene Urumaco Formation of Venezuela, is described on the basis of a poorly preserved right maxillary fragment with brachydont cheek teeth. Teeth and alveoli preserved are interpreted as part of the alveolus of P3 and P4–M3. The new taxon differs from Megadolodus, the only other known genus of the subfamily, in having a proportionally smaller P4 and M1, the latter elongated antero-posteriorly and with the protocone root more mesial than that of the hypocone. Bounodus enigmaticus gen. et sp. nov., reinforces the hypothesis that the Megadolodinae represent a distinct radiation within the Proterotheriidae, the two other major clades being the Anisolambdinae and Proterotheriinae.