Primer Congreso Uruguayo de Zoología - Sociedad Zoológica del ...

FIRST NEOGENE TYPOTHERIA (MAMMALIA, NOTOUNGULATA, HEGETOTHERIIDAE) OFURUGUAYBostelmann E. & Rinderknecht A.Museo Nacional de Historia Natural. Montevideo, Uruguay. ebostel@yahoo.comTypotheria constitutes one of the two suborders of the extinct Notoungulata, the most diverse group of native SouthAmerican ungulates ever recorded. So far, the occurrence of typotheres in Uruguay has only been registered inPaleogene sediments of the Fray Bentos Formation (late Oligocene, Deseadan SALMA). In this contribution wedescribe remains of a Neogene hegetotheriine typothere (family Hegetotheriidae, subfamily "Hegetotheriinae"),collected in the "Kiyú lithofacies" of the Camacho Formation, Playa Arazatí, San José Department. The material ishoused at the Museo Nacional de Historia Natural, Montevideo. MNHN 2681 is a partially complete mandible withthe left hemimandible preserving most of the horizontal ramus, the alveoli of the i1 - p2, the p3 - m3 dental series,and part of the ascending ramus. The right hemimandible is broken at the level of the p4, retaining only the i1, i2, p2and p3. The study of the dentition confirmed the absence of p1 and the lack of a post-canine diastema. Generaldimensions in conjunction with: 1) presence of thick cementum, deep sulcus, and angular borders on the buccal facesof lower molars; 2) a reduced p2; 3) convex lingual faces and narrow distal faces of lower molars; and 4) a bilobedm3, allocate this remains to Hemihegetotherium and specifically to H. achataleptum, the type species of the genus.Hemihegetotherium has been described from Miocene sediments (middle to late Miocene Laventan to HuayquerianSALMAs) of Bolivia, Argentina, and probably Venezuela. A bivariate plot on m1 length vs. width approximate MNHN2681 to specimens collected in southeastern localities of La Pampa Province, Argentina. The presence of H.achataleptum in Arazatí provides a new taxa of typical Huayquerian affinities to the "Kiyú lithofacies" - vertebratefauna, an apparent contradiction with recent isotopic dates that suggest an earlier (Burdigalian, early Miocene) agefor these deposits.OLIGOCENE GLYPTODONTIDAE (MAMMALIA, CINGULATA) FROM THE FRAY BENTOSFORMATION OF URUGUAYBostelmann E. 1 , Rinderknecht A. 1 , Ciancio M.R. 2 , Toriño, P. 3 & Perea D. 31 Museo Nacional de Historia Natural. Montevideo, Uruguay. 2 CONICET. Departamento de Paleontología de Vertebrados, Museo de LaPlata, B1900. La Plata, Argentina. 3 Departamento de Evolución de Cuencas, Facultad de Ciencias. Montevideo, Uruguay.ebostel@yahoo.com.Excluding the enigmatic Glyptatelinae, Paleogene glyptodontids are extremely rare in the fossil record. Indeed, theonly unquestionable published remains belong to isolated osteoderms assigned to an unidentifiedPropalaehoplophorinae from the late Oligocene El Pajarito locality of Chubut Province, Argentina. Nevertheless, thefirst mention of Oligocene glyptodontids was made by A. Castellanos based on two isolated osteoderms collected inthe Barranca de Los Loros, at the Colonia Department, southwestern Uruguay. The paleontology collection of theMuseo Municipal “Prof. Lucas Roselli” (MLR) houses remains of an unpublished “non glyptateline” glyptodontidlabeled as “Bertawileria” sp., here described in detail. MRL 702 includes ten almost complete osteoderms exhumedfrom the Fray Bentos Formation mudstones, in the “Barrancas de la Zona Franca del Puerto de Nueva Palmira”, a nowdisappeared locality supplanted by the facilities of the international harbor. The remains represent different regionsof the carapace; four partial osteoderms from the dorso-lateral area; three lateral rectangular ones; two from thelateral border; and one anterior semi-mobile piece. All of them exhibit a punctuated, flat and smooth externalsurface, with rugose extensions on the contact zone. Ornamentation consists in the typical “rossetta”-pattern with analmost circular big central figure surrounded by numerous small prismatic peripheral figures, all delimited by shallownarrow sulcus with small foramina in their intersections. In accordance to this morphology we tentatively assign theremains to Propalaehoplophorinae indet. MLR 701 consists in three postcranial remains associated to 702: 1) theproximal portion of a right tibia with the articular surfaces for the femur; 2) a possible carpal bone, and 3) onefragmented articular bone of uncertain position. Our investigations shows that the past diversity of OligoceneCingulata in Uruguay, while scant, is quite relevant to improve a better knowledge on the early diversity of SouthAmerican fossil cingulates.74 Primer Congreso Uruguayo de Zoología