Lílian Paglarelli Bergqvist

A new cingulate (Mammalia: Xenarthra), Pachyarmatherium brasiliense sp. nov., from the Late Pleistocene of Northeastern Brazil

ABSTRACT Pachyarmatherium is an enigmatic cingulate genus formerly recognized as Dasypodoidea, but tentatively assigned to the poorly known subfamily Glyptatelinae (Glyptodontidae) by later authors. A new species is described from the late Pleistocene of northeastern Brazil. The material comprises several isolated osteoderms, carapace fragments, and miscellaneous postcranial material. The new species, Pachyarmatherium brasiliense, differs from the North American Pachyarmatherium leiseyi in being larger and in having osteoderms with heptagonal shape, main figures with oblong, subrounded and polygonal outline (instead of only polygonal), and a larger number of peripheral figures. To clarify the affinities of Pachyarmatherium, a cladistic analysis was conducted of 48 morphological postcranial characters and scored for 11 cingulates (the new species, four dasypodids, one pampathere and five glyptodontids) and two pilosans used as outgroup taxa. In the most parsimonious topology obtained, Pachyarmatherium is the sister-group to a clade including Pampatheriidae and Glyptodontidae. This result contradicts the previous tentative allocation of Pachyarmatherium to the Glyptodontidae, and indicates that the glyptodont-like characters of the carapace and osteoderms of Pachyarmatherium are homoplasies shared with glyptodonts. The taxonomic validity of the genera Pachyarmatherium and Neoglyptatelus is recognized, but the morphological evidence from the external ornamentation of osteoderms does not offer support for the placement of Pachyarmatherium within Glyptatelinae.

Revisiting the intertropical Brazilian species Hoplophorus euphractus (Cingulata, Glyptodontoidea) and the phylogenetic affinities of Hoplophorus

ABSTRACT The genus Hoplophorus is one of the most distinctive glyptodonts from the Quaternary deposits of the intertropical area of Brazil. In this paper, we redescribe cranial and postcranial elements and describe some new tarsal elements belonging to the species Hoplophorus euphractus from caves from Minas Gerais state, southern Brazil, in order to provide a better diagnosis for the genus. The material examined shows several striking, distinctive characters relative to Neosclerocalyptus, besides those previously reported, reinforcing the validity of Hoplophorus. On the other hand, we find that the postcrania of Hoplophorus presents striking, unreported resemblances with Panochthus (e.g., more lateromedially elongated cuboid facet of navicular and caudal tube with large lateral figures separated from the terminal ones by a wide space). In order to infer the relationships of Hoplophorus and to reevaluate the monophyly of the tribe Hoplophorini and the subfamily Hoplophorinae (in which Hoplophorus was previously allocated), we carried out a cladistic analysis of 18 taxa, including 13 glyptodont genera and five cingulate outgroups, scored for 151 cranial, dental, and postcranial characters. The most parsimonious tree shows that Hoplophorinae and Hoplophorini are both paraphyletic and has Hoplophorus as the sister group to Panochthus based mostly on synapomorphies of the caudal tube. We propose: (1) restricting the definition of the tribe Hoplophorini to the lineage represented by Hoplophorus, making it the sister group to Panochthini within Panochthinae (= Hoplophorus + Panochthus); and (2) a new subfamily, Neosclerocalyptinae, represented by Neosclerocalyptus, the sister group to Panochthinae.

A new Eocaiman (Alligatoridae, Crocodylia) from the Itaboraí Basin, Paleogene of Rio de Janeiro, Brazil

A new small species of Eocaiman is described on the basis of three anterior left mandibular rami and one isolated tooth. The specimens came from the middle-upper Paleocene Itaboraí Basin (Rio de Janeiro State, Brazil; Itaboraian South American Land Mammal Age). The new taxon differs from the other two Eocaiman species, such as its small size, likely participation of the splenial in the mandibular symphysis, a reduced angle between the longitudinal axis of the symphysis and the mandibular ramus, and enlarged ninth and tenth dentary teeth (in addition to the large first and fourth dentary teeth). The participation of the splenial in the mandibular symphysis is a unique character among caimanines (with the only possible exception being Tsoabichi greenriverensis). The new taxon provides new information on the taxonomic and anatomical diversity of the genus Eocaiman, a taxon of prime importance to understand the evolutionary origins of caimans given its position as the basalmost member of Caimaninae. Furthermore, the new taxon has a relatively small body size in comparison with other species of Eocaiman, a case paralleled by other Itaboraian reptilian groups (e.g. snakes), suggesting that this ecosystem provides critical data to test the relationship between reptilian body size and climate. http://zoobank.org/83636F22-D121-4A77-9141-BE68987B6CBF

Enamel structure of paleocene mammals of the São José de Itaboraí basin, Brazil. ‘Condylarthra’, Litopterna, Notoungulata, Xenungulata, and Astrapotheria

Abstract During mammalian evolution the simple radial enamel, where prisms follow a straight course from the dentin-enamel junction to the tooth surface, gave rise to the typical arrangement of layers of prisms forming Hunter-Schreger bands (HSB). The formation of HSB is believed to have improved the physical properties of enamel. The pattern of HSB has been used to infer relationships between feeding habits and enamel structure. The evolution of enamel structure in the South American faunas is poorly known. Most studies have relied mainly on fossil teeth of Europe and North America mammals, and the majority of the taxa studied are from the Eocene or younger ages. In the present work the patterns of HSB in the enamel of herbivorous mammals from the Paleocene of the São José de Itaborai basin, Brazil were investigated. Vertical HSB were present in the teeth of large animals (first lower molar width >8 mm), while transverse HSB were present in taxa with first lower molar width ranging from 5.6 to 3 mm. The only exception was Lamegoia conodonta (first molar width = 10.3 mm). However, maybe to compensate for its larger size, in L. conodonta the transverse HSB were highly undulated. Our results indicate that the development of vertical HSB in large lophodont and bunolophodont herbivors may have occurred as a functional adaptation. Vertical HSB wear at a slower rate than transverse HSB, and this adaptation would enhance functional durability of enamel, extending the overall longevity of the teeth and the animals life span.

Theropod teeth from the Marília Formation (late Maastrichtian) at the paleontological site of Peirópolis in Minas Gerais State, Brazil

Theropods comprise the most common vertebrate remains in the fossil assemblage from the Serra da Galga Member, Marilia Formation (late Maastrichtian) in the Bauru Basin Peiropolis paleontological site (Uberaba Town, Minas Gerais State), in southeastern Brazil. In this study, cross-sectional outlines of the teeth and wrinkles on the surfaces of the crowns were used to group the teeth into nine morphological classes. The tooth cross-sections were drawn using a copper wire to contour the outlines of the most proximal portions of the tooth crowns. Other features were analyzed using a microscope. Within the nine morphological classes, morphotypes one and two can be assigned to the Abelisauridae, and morphotypes three to seven belong to the Carcharodontosauridae. This is the most abundant record of Abelisauridae in Minas Gerais State, Brazil. Morphotypes eight and nine were not identified because they do not have any diagnostic features of known Gondwanan or Laurasian taxa. The presence of Carcharodontosauridae teeth in the Member of Serra da Galga (late Maastrichtian) is the youngest record for this family.

The intertropical Brazilian species of Panochthus (Xenarthra, Cingulata, Glyptodontoidea): a reappraisal of their taxonomy and phylogenetic affinities

ABSTRACT Four species of Panochthus (P. greslebini, P. jaguaribensis, P. oliveira-roxoi, and P. rochai) have been described from the late Pleistocene of northeastern Brazil. P. oliveira-roxoi, and P. rochai have been considered loosely as synonyms of P. greslebini. This paper reevaluates the referred material, diagnostic characters, and validity of these species and includes a cladistic analysis of 25 caudal tube and carapace characters to determine their positioning relative to other species of Panochthus. P. greslebini and P. jaguaribensis are valid species and differ from the other species of Panochthus by unique combinations of caudal tube characters. Carapace fragments previously attributed to P. jaguaribensis are in fact fragments of cephalic shields. These fragments and the isolated ostoderms previously described for P. jaguaribensis cannot be confidently assigned to this species. We support the interpretation of P. rochai as a junior synonym of P. greslebini, but P. oliveira-roxoi is actually a nomen dubium instead of a synonym of P. greslebini. Our analysis yielded a fully resolved tree in which Panochthini, as traditionally defined, is paraphyletic and the species formerly attributed to Panochthus form a monophyletic group, echoing recent findings based on a different dataset. Within Panochthus, the Brazilian species form a clade with the Bonaerian species P. subintermedius, which is the sister species to P. greslebini. Instead of a more basal position suggested in early and recent works, P. jaguaribensis is deeply nested within the clade encompassing the species of Panochthus.

Osteoderm Histology of Late Pleistocene Cingulates from the Intertropical Region of Brazil

During the Late Pleistocene, several possibly endemic cingulate species, known mostly from isolated osteoderms, carapace fragments, and caudal tubes, coexisted in the Brazilian Intertropical Region. Here, we describe the osteoderm microstructure of Pachyarmatherium brasiliense, as well as the glyptodonts Panochthus greslebini, Panochthus jaguaribensis and Glyptotherium sp., in order to provide additional species-diagnostic characters and shed light on their evolutionary relationships. Pachyarmatherium brasiliense lacks several derived features shared by glyptodonts and pampatheres, such as extensive bone remodeling, fibers arranged in large bundles, and relatively poorly developed layers of compact bone, thus supporting its exclusion from glyptodonts as suggested by a recent cladistic study. The osteoderm histology of P. greslebini resembles that of other species of Panochthus (e.g., Panochthus frenzelianus). By contrast, the presence of relatively thick layers of compact bone, the configuration and size of resorption areas, the absence of randomly oriented lateral fiber bundles, and the absence of an intermediary region between the compact and trabecular bone potentially support the exclusion of Panochthus jaguaribensis from the genus. Finally, osteoderms of the Brazilian specimens of Glyptodontinae share histological features with Glyptotherium floridanus, rather than Glyptodon, thus reinforcing their assignment to Glyptotherium. These results highlight the relevance of histological osteoderm characters in cingulate systematics, ands call for further and more comprehensive studies.

Deciduous Premolars of Paleocene Litopterns of Sáo José de Itaboraí Basin, Rio de Janeiro, Brasil

Abstract The order Litopterna is represented in the São José de Itaboraí basin by four species belonging to the families Protolipternidae (Protolipterna ellipsodontoides, Miguelsoria parayirunhor and Asmithwoodwardia scotti) and Proterotheriidae (Paranisolambda prodromus). Only the deciduous teeth of P. prodromus are known so far. Isolated milk premolars are described for P. ellipsodontoides and M. parayirunhor. The known specimens assigned to P. prodromus are redescribed. No milk teeth are known for A. scotti. The upper and lower milk teeth of Protolipternidae, especially dP3, are more molarized than their successors, resembling, in several features later Proterotheriidae. They provide new support for the placement of this family within the order Litopterna. The analysis of the wear level of dp2–4/dP2–4 and X-ray images of the lower jaw of P. prodromus suggests that the second teeth of the premolar series, in upper and lower jaw, are retained milk premolars. Some information on tooth replacement pattern of P. ellipsodontoides and P. prodromus are also provided.

Elucidating Bone Diseases in Brazilian Pleistocene Sloths (Xenarthra, Pilosa, Folivora): First Cases Reported for the Nothrotheriidae and Megalonychidae Families

Abstract. Nothrotherium maquinense, Ahytherium aureum and Australonyx aquae are ground sloths endemic of the late Pleistocene of the Brazilian Intertropical Region for which, as opposed to other xenarthrans such as megatheriid sloths and glyptodonts, no information regarding pathological conditions is available. Herein, we describe, based on an anatomopathological examination, four types of lesions for N. maquinense (spondyloarthropathy, Schmorls node, vertebral trauma and unspecific infection) and one lesion for A. aureum (osteochondritis dissecans). No lesions were observed in A. aquae. Although several different diseases have been diagnosed, considering the significant number of specimens (2,232) and individuals (41) analyzed, low prevalence marks them all.

Reassessment of the enigmatic crocodyliform "Goniopholis" paulistanus Roxo, 1936: Historical approach, systematic, and description by new materials

The Crocodyliformes are the most represented vertebrate clade in the Upper Cretaceous sequences of the Bauru Group, Paraná Basin. However, some of the species described have an uncertain taxonomic status and phylogenetic position. For instance, “Goniopholis” paulistanus has been assigned as a nomem dubium, due to its description being based on scarce material. The “G”. paulistanus specimens (i.e. teeth and a left tibia) were discovered in two different localities in São Paulo state: Mirandópolis and Valparaíso municipalities; where the upper interval of the Adamantina Formation (Early Maastrichtian of Bauru Group) crops out. Revisiting these specimens, we observed multicrenulated teeth in middle dentary toot- row, a remarkable feature only shared with teleosaurids Machimosaurus hugii (Upper Jurassic of Laurasia) and M. rex (Lower Cretaceous of Tunisia). This apomorphy was also recognized in new material from the Alfredo Marcondes municipality (Presidente Prudente Formation), which are here also referred to “G”. paulistanus. We recognized the teeth of “G.” paulistanus as the lectotype, however the tibia cannot be assigned to a species as it was not collected in association with the teeth. We performed a phylogenetic analysis with a data matrix composed of 388 characters and 86 taxa, analyzed in TNT. The strict consensus tree recovered Neosuchia and Ziphosuchia (Notosuchia + Sebecia) within Mesoeucrocodylia. The species “G” paulistanus is valid, as a distinct and new genus within Sebecia, in a polytomy with Barreirosuchus, Pepesuchus, Itasuchus and Peirosaurus, forming the clade Itasuchidae. Stolokrosuchus is the sister taxon to Itasuchidae, the sister group of all other Sebecia (Peirosauridae (Mahajangasuchidae + Sebecidae and taxa affinis)). The clades Ziphosuchia, Sebecia and Itasuchidae are here redefined, and we find the last two clades to be more closely related to terrestrial notosuchids than to semiaquatic neosuchians.