New material of the enigmatic cingulate Eocoleophorus glyptodontoides Oliveira, Ribeiro and Bergqvist, 1977 (Mammalia: Cingulata) from Taubate basin, Sao Paulo State, Brazi

ABRANTES, E.A., AVILLA. L. AND VIZCAÍNO, S.F.

Rio de Janeiro, Brasil

Congreso; II Congresso Latinoamericano de Paleontologia de Vertebrados; 2005

Museu Nacional y Universidade Federal do Rio de Janeiro

NEW MATERIAL OF THE ENIGMATIC CINGULATE EOCOLEOPHORUS GLYPTODONTOIDES OLIVEIRA, RIBEIRO & BERGOVIST, 1997 (MAMMALIA: CINGULATA) FROM TAUBATE BASIN, SAO PAULO STATE, BRAZIL ABRANTES, Aparecida Leite1, AVILLA, Leonardo dos Santos1,2,  VIZCAÍNO, Sergio Fabián3. 1Departamento de Geología, IGEO, Universidade Federal do Río de Janeiro. CAPES. 2Herpotologia, Departamento de Vertebrados, Museo Nacional, Universidade Federal do Río de Janeiro. 3Departamento Científico de Paleontología de Vertebrados, Museo La Plata, Argentina. CONICET. Eocoleophorus gliptodontoides was described based on isolated osteoderms collected at the greenish clay of the Tremembé Formation (Deseadean SALMA, Upper Oligocene‑lowermost Miocene), Taubaté Basin. Previous authors suggested morphological resemblances of this taxon to each of the main cingulate lineages ‑ dasypodids, glyptodontids, and pampatheriids ‑ although they did not assign it to any of these lineages. New material assignable to Eocoleophorus gliptodontoides allowed to improve and emend the diagnosis, and also to review its systematic position within cingulates. The material consists on non‑articulated osteoderms and two fragments of femur collected at the same outcrop of the holotype series and housed at Museu de Historia Natural de Taubaté, Sao Paulo State (VT 560, distal portion of femur; VT 559, proximal portion of femur; VT 1395, VT 1396, VT 1397, VT 1398, VT 1429 e VT 1442, isolated osteoderms). All diagnostic features pointed out for E. glyptodontoides in the original description are clearly observed in this new material. The buckler osteoderms are pentagonal or hexagonal, bearing an isodiametric principal figure distally displayed, and occupying most of the surface. Proximally, a single row of small isodiametric peripheral figures is present in most osteoderms, although some of them bear an additional row of peripheral figures. The number of peripheral figures ranges from three to eight. Twelve to fourteen foramina are observed in the sulcus that surrounds the principal figure, but some foramina are also present in sulci surrounding the peripheral figures. The same buckler osteoderm morphological pattern, observed in movable osteoderms, leaves no doubt about their association. The movable plates present a U‑shaped principal figure, and some of them also bear a slightly longitudinal keel. The principal figure is surrounded by isodiametrical peripheral figures and a sulcus, which shows five to eight foramina. Femur remains are represented by proximal left and distal right fragments. The proximal fragment bears no distinct neck, where a very pronounced rounded head lies. The fovea is very large and deep, and is mediocaudally positioned. The greater trochanter projects beyond the head. The trochanteric fossa is shallow, and long lesser trochanter is positioned just below the head. Although the only preserved portions of the femur are the proximal and distal ends, the dimension of preserved small parts of both shafts indicate relatively slender diaphysis. Moreover, the proximal shaft is transversally rounded, while the distal is anteroposteriorly compressed. The distal portion has an internal condyle extending far distal from the external condyle and it bears a large trochlea. The osteoderms of E. glyptodontoides share some morphological resemblances to glyptodontid, dasypodid and pampatheriid. However, contrary to glyptodontids, its plates are very thin, the movable osteoderms bear well‑developed anterior articular surfaces, and the internal condyle of the femur extends far beyond the external. Both features are shared by dasypodids and pampatheriids. Nonetheless, pampatheriids do not present peripheral figures on their osteoderms; instead of that, they bear the characteristic texture of small punctuations and pits. The only group within dasypodids that shares attributes with E. glyptodontoides is Dasypodini: buckler osteoderms isodiametric, hexagonal or pentagonal shaped, bearing principal figure also isodiametric and posteriorly displaced, and occupying more than half of osteoderm total surface. Dasypodini include three taxa: Anadasypus (Laventan SALMA, middle Miocene of Colombia and the middle to late Miocene of Ecuador); Propraopus (Late Pliocene‑Pleistocene, South America) and the extant Dasypus (Late Pliocene to Recent, South to North America). Within Dasypodini, E. glyptodontoides shares longitudinal keel on principal figure with A. hondanus (Colombia). The validity of E. glyptodontoides is supported by the unique features presented on the original description, and also some new diagnostic characters erected here: movable osteoderms presenting inverted U‑shaped aspect principal figure, while the other Dasypodini present a characteristic inverted V­shaped; and twelve to fourteen (buckler), and five to eight (movable), foramina in the sulcus surrounding the principal figure, whereas others bear five or less. E. glyptodontoides represents the oldest record for the Dasypodini and suggests an early evolution of the group in the intertropics or at least out of Patagonia.