Topic
Cingulata
About: Cingulata is a research topic. Over the lifetime, 168 publications have been published within this topic receiving 3084 citations.
Papers published on a yearly basis
Papers
TL;DR: New information is presented on the comparative morphology and histology of osteoderms and their associated soft tissues in 11 extant and fossil xenarthrans to represent a relatively robust foundation upon which to base soft‐tissue reconstructions of extinct xenarthans.
Abstract: Reconstruction of soft tissues in fossil vertebrates is an enduring challenge for paleontologists. Because inferences must be based on evidence from hard tissues (typically bones or teeth), even the most complete fossils provide only limited information about certain organ systems. Osteoderms (“dermal armor”) are integumentary bones with high fossilization potential that hold information about the anatomy of the skin in many extant and fossil amniotes. Their importance for functional morphology and phylogenetic research has recently been recognized, but studies have focused largely upon reptiles, in which osteoderms are most common. Among mammals, osteoderms occur only in members of the clade Xenarthra, which includes armadillos and their extinct relatives: glyptodonts, pampatheres, and, more distantly, ground sloths. Here, I present new information on the comparative morphology and histology of osteoderms and their associated soft tissues in 11 extant and fossil xenarthrans. Extinct mylodontid sloths possessed simple, isolated ossicles, the presence of which is likely plesiomorphic for Xenarthra. More highly derived osteoderms of glyptodonts, pampatheres, and armadillos feature complex articulations and surface ornamentation. Osteoderms of modern armadillos are physically associated with a variety of soft tissues, including nerve, muscle, gland, and connective tissue. In some cases, similar osteological features may be caused by two or more different tissue types, rendering soft-tissue inferences for fossil osteoderms equivocal. Certain osteological structures, however, are consistently associated with specific soft-tissue complexes and therefore represent a relatively robust foundation upon which to base soft-tissue reconstructions of extinct xenarthrans. J. Morphol., 2006. © 2006 Wiley-Liss, Inc.
144 citations
21 Dec 1981
TL;DR: Gillette et al. as discussed by the authors described the taxonomic validity of G. texanum and G. mexicanum in the genus G. anzonae and two species known from isolated localities in Mexico, G. cyltndricum and g. floridanum.
Abstract: Gillette, David D., and Clayton E. Ray. Glyptodonts of North America. Smithsonian Contributions to Paleobiology, number 40, 255 pages, 97 figures, 70 tables, 1981.—All known North American glyptodonts belong in the genus Glyptothenum Osborn, 1903 (Family Glyptodontidae, Subfamily Glyptodontinae). Junior synonyms are Brachyostracon Brown, 1912; Boreostracon Simpson, 1929; Xenoglyptodon Meade, 1953; and all assignments of North American specimens to Glyptodon Owen, 1838. The ancestral species is Glyptothenum texanum from the Early Pleistocene Tusker (Arizona) and Blanco (Texas) local faunas of the Blancan Land Mammal Age; G texanum is smaller and lacks many of the exaggerated features of the descendant species. The descendant species are G. anzonae (Blancan? and Irvingtonian); G. floridanum (Rancholabrean); and two species known from isolated localities in Mexico, G. cyltndricum and G. mexicanum. The taxonomic validity of G. mexicanum is questionable. The geographic distribution and faunal associations of Glyptothenum clearly indicate tropical or subtropical habitats. North American glyptodonts exhibit extreme tendencies toward hypsodonty and homodonty in the dentition, and they lack both incisiform and caniniform teeth. They probably fed on soft vegetation near permanent bodies of water. Graviportal limb proportions and details of the gross osteology suggest slow and cumbersome locomotion, which probably precluded occupation of upland habitats. A substantial expansion in the number of specimens available for study has extensively improved our knowledge of the gross osteology of Glyptothenum. especially for G. texanum and G. anzonae. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Gillette, David D. Glyptodonts of North America. (Smithsonian contributions to paleobiology ; no. 40) Bibliography: p. Supt. of Docs, no.: SI 1.30:40 1. Glyptodontidae. 2. Paleontology—North America. I. Ray, Clayton Edward, joint author. II. Title. III. Series: Smithsonian Institution. Smithsonian contributions to paleobiology; no. 40. QE701.S56 no. 40 IQE882.E2] 560s [569'.31) 80-607040
133 citations
TL;DR: The absence of cartilage precursors indicates that osteoderms are dermal elements, possibly related to the all‐encompassing vertebrate dermal skeleton (exoskeleton), and instead is comparable with intramembranously derived elements of the skull.
Abstract: Among modern mammals, armadillos (Xenarthra, Cingulata) are the only group that possesses osteoderms, bony inclusions within the integument. Along the body, osteoderms are organized into five discrete assemblages: the head, pectoral, banded, pelvic, and tail shields. The pectoral, banded, and pelvic shields articulate to form the carapace. We examined osteoderm skeletogenesis in the armadillo Dasypus novemcinctus using serial and whole-mount histochemistry. Compared with the rest of the skeleton, osteoderms have a delayed onset of development. Skeletogenesis begins as condensations of osteoblasts secreting osteoid, localized within the papillary layer of the dermis. Osteoderm formation is asynchronous both within each shield and across the body. The first osteoderms to mineralize are situated within the pectoral shield of the carapace, followed by elements within the banded, head, pelvic, and tail shields. In general, within each shield ossification begins craniomedially and proceeds caudally and laterally, except over the head, where the earliest elements form over the frontal and parietal bones. The absence of cartilage precursors indicates that osteoderms are dermal elements, possibly related to the all-encompassing vertebrate dermal skeleton (exoskeleton). The mode of development of D. novemcinctus osteoderms is unlike that described for squamate osteoderms, which arise via bone metaplasia, and instead is comparable with intramembranously derived elements of the skull.
119 citations
TL;DR: Maximum likelihood and Bayesian phylogenetic analyses supported the monophyly of Dasypodinee, Tolypeutinae, and Euphractinaes, with the latter two armadillo subfamilies strongly clustering together, and low statistical support values associated with almost equal distributions of apomorphies among alternatives suggested that two parallel events of rapid speciation occurred within these two armADillo sub families.
90 citations
Journal Article•
TL;DR: Oliveira et al. as mentioned in this paper conducted a comparative morphological analysis of the osteoderms and post-cranial bones from the Itaboraian (upper Paleocene) of Brazil.
Abstract: Here we present new information on the oldest Xenarthra remains. We conducted a comparative morphological analysis of the osteoderms and post-cranial bones from the Itaboraian (upper Paleocene) of Brazil. Several osteoderms and isolated humeri, astragali, and an ulna, belonging to at least two species, compose the assemblage. The bone osteoderms were assigned to Riostegotherium yanei Oliveira & Bergqvist, 1998, for which a revised diagnosis is presented. The appendicular bones share features with some edentate taxa. Many of these characters may be ambiguous, however, and comparison with early Tertiary Palaeanodonta reveals several detailed, derived resemblances in limb anatomy. This suggests that in appendicular morphology, one of the Itaborai Xenarthra may be the sister-taxon or part of the ancestral stock of Palaeanodonta.
87 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 13 |
| 2020 | 10 |
| 2019 | 10 |
| 2018 | 3 |
| 2017 | 15 |
| 2016 | 6 |