Neosclerocalyptus was an extinct genus of glyptodont that lived during the Pliocene, Pleistocene, and Holocene of Southern South America, mostly Argentina.[1] It was small compared to many glyptodonts at only around 2 meters long and 360 kilograms.[2]
The genus name Neosclerocalyptus is a modification of the name of its synonym, Sclerocalyptus, and derived from the Greek roots neo- meaning "young" or "new", scleros meaning "hard", and -calyptos meaning "covering", referring to the armored carapace of the animal.[3] The type species, N. ornatus, specific name meaning is "adorned" after the patterns on the holotype osteoderms.
History and taxonomy
Dermal armor of MLP-16-28, a skeleton of N. ornatus.
Fossils of Neosclerocalyptus were first collected by a "Sir Woodbine Parish, KH" from the Pleistocene strata near the Matanzas River in Buenos Aires Province, Argentina, but where later sent to the Royal College of Surgeons in the UK, where they were later described by paleontologist Sir Richard Owen in 1845 as a species of the earlier named Glyptodon, naming it Glyptodon ornatus.[4] The fossils were fragmentary, consisting only of 4 dorsal carapace osteoderms, but were destroyed during German bombing raids during World War II.[2] The strata where the fossils were collected may be from the Ensenadan of the Pleistocene based on later analysis of the strata around the Matanzas River.[2] Due to the fossils being lost, a neotype was designated by Richard Lydekker in 1887 that consisted of a complete dorsal carapace, caudal rings, and a caudal tube that were also collected from Buenos Aires and deposited in the collections of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia, but it couldn't be found in the museum's collections. Lydekker illustrated a complete skeleton with a complete carapace in 1894 that had been collected from the Ensenadan deposits of the Mar del Plata in Buenos Aires that is extremely similar to that of the neotype and has been used as the "model" specimen of the species since.[5][2] This is shown by Argentine paleontologist Florentino Ameghino when he stated, "It is a superb sample of a fully grown adult (.) and it should be preferably consulted by paleontologists because it represents approximately the actual shape of the animal".[6]
One of the best known species, N. pseudornatus, was first described by Florentino Ameghino in 1889 based on 13 dorsal carapace osteoderms that were collected from the Pleistocene strata in the "Toscas del Rio de La Plata" in Buenos Aires, though Ameghino named it as a species of the Brazilian glyptodont Hoplophorus.[7][2] Since its naming, dozens more specimens have been assigned to N. pseudornatus, including skulls.[2][1] In 1891, Ameghino erected the genus name Sclerocalyptus for the Brazilian glyptodont Hoplophorus euphractus, erroneously believing that the genus name was preoccupied, and placed Glyptodon ornatus and Hoplophorus pseudornatus among other species in the genus.[8] Subsequently it was clear that these two species differ considerably with each other and, due to the rules of zoological nomenclature, the name Sclerocalyptus was considered synonymous with Hoplophorus (described first), and it was necessary to establish a new genus for Sclerocalyptus ornatus: Paula Couto, in 1957, then established the Neosclerocalyptus genus.[9] The taxonomic confusion concerning the names of this species continued throughout the twentieth century and for the first part of the 2000s, but N. ornatus has consistently been seen as valid and the type species. Other species named include N. castellanosi (late Pliocene), N. pseudornatus (lower Pleistocene - Medium), N. gouldi (middle Pleistocene) and N. paskoensis (late Pleistocene-early Holocene).[10] However, many other species that have been named have been synonymous with previously named species or synonymous with other genera, most of them named based on fragmentary fossils.[11]
Species
The following list is after Quiñones et al (2020),[12] Zurita et al (2009),[2] and Zurita (2007).[11] Zurita et al (2009) argued that only 2 species of Neosclerocalyptus are valid (N. ornatus & N. pseudornatus),[2] but subsequent analyses have kept 5 species as valid.[10][12]
Lomaphorus chapalmalensis Ameghino, 1908; Holotype is dubious, with similarities to Neosclerocalyptus and Eosclerocalyptus.[2]
Hoplophorus clarazianus Ameghino, 1889; Holotype is several osteoderms and a skull, all fossils have been lost and the species is dubious, though the skull has been referred to Neosclerocalyptus.[1]
Hoplophorus compressus Ameghino, 1882; Holotype osteoderms' supposed diagnostic traits are the same as those in Neosclerocalyptus species, making it a nomen dubium.[2]
Hoplophoruscordubensis Ameghino, 1888; Dubious and possibly synonymous with Neosclerocalyptus or Isolina.[11]
Glyptodon elevatus Nodot, 1857; Holotype osteoderms' supposed diagnostic traits are the same as those in juveniles of Neosclerocalyptus species, making it a nomen dubium.[2]
Hoplophorusevidens Ameghino, 1889; Holotype is dubious but referred material represents a large, unique form of Neosclerocalyptus.[11]
Hoplophorusheusseri Ameghino, 1889; Dubious at the species level.[11]
Hoplophorusparanensis Ameghino, 1883; Synonymous with Neosclerocalyptus, but dubious at the species level.[13]
Dubious:
N. (Hoplophorus) bergi (Ameghino, 1889); Holotype is dubious and similar to that of Hoplophorus and Panochthus.[11]
N. (Sclerocalyptus) matthewi (Castellanos, 1925); Holotype is dubious and is identical to that of "Hoplophorus cordubensis".[11]
N. (Hoplophorus) migoyanus (Ameghino, 1889); Dubious at family level.[11]
N. (Hoplophorus) perfectus (Gervais & Ameghino, 1880); Holotype is dubious and more similar to that of Hoplophorus and Panochthus.[11]
N. (Hoplophorus) scrobiculatus (Ameghino, 1889); Holotype may be a chimera and has been declared a species inquirenda.[2]
Description
Like all glyptodonts, this genus also possessed an armored carapace with osteoderms melted with each other, rigid, which covered a large part of the body and head. Neosclerocalyptus was a medium-sized glyptodont, and rarely exceeded 2 meters in length,[9] with N. pseudornatus as the smallest species.[12] One of the largest specimens, CCA-16A, that has been referred to an unnamed species of Neosclerocalyptus was estimated to weigh 471 kilograms (or 1038 lbs), making it the largest definitively known species of Neosclerocalyptus.[12] It was characterized by an elongated and low carapace with two lateral "wings" projected forward in the area of the cervical append.[11]
Fragment of the dorsal carapace of N. ornatus.
Neosclerocalyptus' carapace contains 50-55 transverse rows along the sides of the shell.[11] The dorsal carapace osteoderms of Neosclerocalyptus preserve a "rossette" pattern, though the antero-ventrally placed ones lack the pattern, with a flat and sub-circular central figure, surrounded by a single row of 7 to 10 polygonal peripheral figures, similar to Propalaehoplophorus. The external morphology of the osteoderms varies in location, with rectangular osteoderms along the dorsal midline in single rows and circular osteoderms covering the middle, side, and proximal carapace portions. From the median part of the dorsal side of the carapace towards the lateral sides of the carapace, osteoderms are progressively smaller, while the central figures of them become more circular. At the anterior regions, the dorsal osteoderms become pentagonal or hexagonal and the central figures become more circular. In the most ventral-lateral region, osteoderms are rectangular with antero-posterior main axis for a wider coverage. On the anterior-dorsal parts of the carapace, osteoderms become more hexagonal, smaller, and flatter in contrast to those of the ventral-lateral region. Central figures tend to be more rounded, increasing in size, and slightly towards the posterior margin of the osteoderm. The osteoderms were thin, strongly sutured, and not depressed in their internal surface, contrary to the tall and robust osteoderms of Glyptodon and Panochthus.[14] In the dorsal region, a slightly depressed smooth central figure was surrounded by a series of large polygonal figures often common to two contiguous plates; the furrows were sharp but narrow and shallow. A large hair holes were present around the cervical inlet. By moving away from the axis, the central figures became more prominent, and they came to occupy practically the entire surface of the small plaques on the side wings. Along the edges of the carapace, the central figure was enlarged and occupied a marginal position, due to the disappearance of the peripheral area along the free margin.[15][11][12]
The tail was protected by four or five mobile rings, each consisting of two series of plates. The terminal part of the tail was protected by a bone tube, almost cylindrical, a little depressed and slightly curved upwards, which corresponded to ten vertebrae. This tube was equipped with two large convex terminal plaques, preceded by side plates that were reduced to the front of the tail, and which were separated from each other via two rows of peripheral figures. The rest of the surface of the caudal tube was made up of oval elements separated by a single series of small polygonal figures.[10][7][11]
The head was protected by a large shield whose armor was well sutured, numerous and equipped with a little visible ornamentation. The profile of the skull was strongly convex, due to the development of frontal sinus; the nasal bones inclined downwards. The orbits were limited in the rear area by an apophysis of the zygomatic arch, which however did not come to join the front bones. The mandible's upright branch was very wide and inclined forward. The most front teeth were simple, while the rear ones were trilobed.[1][11]
Classification
Neosclerocalyptus represents one of the best known glyptodont genera, due to the significant fossil remains belonging to N. ornatus and the number of species. Neosclerocalyptus is part of the monogeneric tribe Neosclerocalyptini that is diagnosed from other Glyptodonts by 6 ambiguous synapomorphies, most of these being from the nasal anatomy and shape of the carapace.[12] The tribe is the sister group to the Hoplophorini, which definitively contains Panochthus and Hoplophorus but may also include other genera like Lomaphorus and Palaehoplophorus, though these genera may be dubious.[12][2] The classification of Neosclerocalyptus has changed many times, first being a Glyptodon species, but also being classified as a hoplophorin, "lomaphorin", and "sclerocalyptin".
The following phylogenetic analysis was conducted by Quiñones et al (2020), which included 5 named species of Neosclerocalyptus and 1 unnamed species:[12]
Neosclerocalyptus is known from the Ensenadan-Lujanian (Middle Pleistocene-Early Holocene) of Chubut, Buenos Aires, La Pampa, Córdoba, Mendoza, San Luis, Santa Fe, Entre Ríos, Corrientes, Chaco, Santiago del Estero, Tucumán, Formosa and Salta Provinces of Argentina, but also the Pleistocene of Uruguay, Paraguay, and Bolivia. Most records of Neosclerocalyptus come from colder and more arid environments, such as the Argentine Pampas and north-central Argentina,[16][2] while fossils from warmer and humid environments are much more rare, such as in Argentine Mesopotamia and western Uruguay.[17][2] The northernmost occurrence of the genus is from Nuapua and Santa Cruz de la Sierra localities in Bolivia,[18][2] while the southernmost one is from Bahia Blanca in Buenos Aires Province.[19][2] The oldest Neosclerocalyptus species is N. castellanosi from the Vorohuean (Late Pliocene), then there are N. pseudornatus and N. ornatus from the Ensenadan (early Pleistocene-middle Pleistocene), N. goudi comes from the Bonaerian (middle Pleistocene), and lastly N. paskoensis fossils date purely to the Lujanian (late Pleistocene-early Holocene).[10][2] During the Ensenadan, the era in which the most Neosclerocalyptus fossils have been found, most of South America underwent a great cooling and more areas became open, arid spaces, though at certain intervals humid environments and rainforests would become more common.[20][21][2] This is also reflected in the size of many of the taxa from this era, with mammal genera like Glyptodon, Doedicurus, Toxodon, and others reaching their peak sizes.[2][22]N. pseudornatus is found in more tropical and even heterogenous environments than that of later species, but the species likely went extinct around 1.168 and 1.016 Ma as part of the "Great Patagonian Glaciation".[23][2]
It seems that some morphological characteristics of Neosclerocalyptus (such as the strong development of the front-nasal sinus) allowed the animal to breathe easier in drier or colder environments than many other Glyptodonts.[24] The fossils of Neosclerocalyptus are more abundant in the areas of Argentina which were more arid during the Pleistocene, and are rarer in the areas where, in the Pleistocene, the climate was more humid and warm.[1][2][25] Glyptodonts have hypsodont dentition, and the teeth also never stopped growing in life, so they are assumed to have fed predominantly on grass. However, they have unusual teeth compared to those of other mammals, featuring three lobes (except for the first two teeth, which have the usual two lobes). The tooth core is made of osteodentine, which is surrounded by a layer of orthodentine, and capped off by cementum instead of enamel. Neosclerocalyptus and its distant relative Neuryurus bear narrower muzzles and being less hypsodont than larger glyptodonts like Doedicurus, suggesting probable bulk-feeding for relatively open environments compared to earlier selective-feeding glyptodonts.[26] This follows the environments known from the time, with large, flat, arid environments with many grazers.[1]
Based on a calcuulation of IFA valuyes of the humerus of Neosclerocalyptus, Neosclerocalyptus would have more cursorial habits than its relatives Glyptodon and Propalaehoplophorus.[27]
Related Research Articles
Glyptodonts are an extinct clade of large, heavily armoured armadillos, reaching up to 1.5 metres (4.9 ft) in height, and maximum body masses of around 2 tonnes. They had short, deep skulls, a fused vertebral column, and a large bony carapace made up of hundreds of individual scutes. Some glyptodonts had clubbed tails, similar to ankylosaurid dinosaurs.
Cingulata, part of the superorder Xenarthra, is an order of armored New World placental mammals. Dasypodids and chlamyphorids, the armadillos, are the only surviving families in the order. Two groups of cingulates much larger than extant armadillos existed until recently: pampatheriids, which reached weights of up to 200 kg (440 lb) and chlamyphorid glyptodonts, which attained masses of 2,000 kg (4,400 lb) or more.
Doedicurus is an extinct genus of glyptodont from South America containing one species, D. clavicaudatus. Glyptodonts are a member of the family Chlamyphoridae, which also includes some modern armadillo species, and they are classified in the superorder Xenarthra alongside sloths and anteaters. Being a glyptodont, it was a rotund animal with heavy armor and a carapace. Averaging at an approximate 1,400 kg (3,100 lb), it was one of the largest glyptodonts to have ever lived. Though glyptodonts were quadrupeds, large ones like Doedicurus may have been able to stand on two legs like other xenarthrans. It notably sported a spiked tail club, which may have weighed 40 or 65 kg in life, and it may have swung this in defense against predators or in fights with other Doedicurus at speeds of perhaps 11 m/s.
Glyptotherium is a genus of glyptodont in the family Chlamyphoridae that lived from the Early Pliocene, about 3.6 million years ago, to the Late Pleistocene, around 15,000 years ago. It had a wide distribution, living in the United States, Mexico, Guatemala, Costa Rica, Honduras, El Salvador, Panama, Venezuela, and Brazil. The genus was first described in 1903 by American paleontologist Henry Fairfield Osborn with the type species being, G. texanum, based on fossils that had been found in the Pliocene Blancan Beds in Llano Estacado, Texas, USA. Glyptotherium fossils have since been unearthed from many more fossil sites, from Florida to Colombia. Another species, G. cylindricum, was named in 1912 by fossil hunter Barnum Brown on the basis of a partial skeleton that had been unearthed from the Pleistocene deposits in Jalisco, Mexico. The two species differ in several aspects, including age, with G. texanum being from the older Early Pliocene to Early Pleistocene strata, whereas G. cylindricum is exclusive to the Late Pleistocene.
Hoplophorus is an extinct genus of glyptodont, a subfamily of armadillos. The only confidently known species was H. euphractus, found in Pleistocene deposits in Brazil, though fossils possibly from another species are known from Bolivia.
Glyptodon is a genus of glyptodont, an extinct group of large, herbivorous armadillos, that lived from the Pliocene, around 3.2 million years ago, to the early Holocene, around 11,000 years ago, in South America. It is one of, if not the, best known genus of glyptodont. Glyptodon has a long and storied past, being the first named extinct cingulate and the type genus of the subfamily Glyptodontinae. Fossils of Glyptodon have been recorded as early as 1814 from Pleistocene aged deposits from Uruguay, though many were incorrectly referred to the ground sloth Megatherium by early paleontologists.
Propalaehoplophorus, also written as Propalaeohoplophorus, is an extinct genus of glyptodont, which lived in South America during the Early Miocene epoch.
Stegotherium is an extinct genus of long-nosed armadillo, belonging to the Dasypodidae family alongside the nine-banded armadillo. It is currently the only genus recognized as a member of the tribe Stegotheriini. It lived during the Early Miocene of Patagonia and was found in Colhuehuapian rocks from the Sarmiento Formation, Santacrucian rocks from the Santa Cruz Formation, and potentially also in Colloncuran rocks from the Middle Miocene Collón Curá Formation. Its strange, almost toothless and elongated skull indicates a specialization for myrmecophagy, the eating of ants, unique among the order Cingulata, which includes pampatheres, glyptodonts and all the extant species of armadillos.
Lomaphorus is a possibly dubious extinct genus of glyptodont that lived during the Pleistocene in eastern Argentina. Although many species have been referred, the genus itself is possibly dubious or synonymous with other glyptodonts like Neoslerocalyptus from the same region.
Boreostemma is an extinct genus of glyptodonts from northern South America. Fossils assigned to the genus were first described as belonging to Asterostemma from southern South America, but have been placed in the new genus Boreostemma by Carlini et al. in 2008. The type species is B. pliocena. Fossils of Boreostemma have been found in the Honda Group of Colombia, in Peru and Venezuela.
Kelenkura is an extinct genus of heavily armored mammals belonging to the subfamily Glyptodontinae, from the family Chlamyphoridae that contain most of the modern armadillos. It was a medium-sized South American animal, distantly related to Doedicurus. Fossils of this genus were recovered in the Arroyo Chasicó Formation and in the Loma de Las Tapias Formation of Argentina in rocks dating back to the Late Miocene epoch.
Kraglievichia is an extinct genus of cingulate belonging to the family Pampatheriidae. It lived from the Late Miocene to the Early Pliocene, and its fossilized remains were discovered in South America.
Proeuphractus is an extinct genus of xenarthran, related to the modern armadillos. It lived from the Early to the Late Miocene, and its fossilized remains were discovered in South America.
Palaehoplophorus is an extinct genus of glyptodont. It lived from the Middle to the Late Miocene, and its fossilized remains were discovered in South America.
Urotherium is an extinct genus of Glyptodont. It lived from the Late Miocene to the Late Pliocene, and its fossilized remains were found in South America.
Plohophorus is an extinct genus of glyptodont. it lived from the Late Miocene to the Late Pliocene, and its fossilized remains were discovered in South America.
Phlyctaenopyga is an extinct genus of glyptodont. It lived from the Late Miocene to the Early Pliocene, and its fossilized remains were discovered in South America.
Neuryurus is an extinct genus of glyptodont. It lived from the Late Pliocene to the Early Holocene, and its fossilized remains were discovered in South America.
Stromaphorus is an extinct genus of Glyptodont. It lived during the Late Miocene, and its fossilized remains were discovered in South America.
Comaphorus is a dubious extinct genus of glyptodont. It lived during the Late Miocene in Argentina, but only one fossil has ever been referred to the animal.
1 2 3 4 5 6 Zurita, A. E.; Scarano, A. C.; Carlini, A. A.; Scillato-Yané, G. J.; Soibelzon, E. (2011). "Neosclerocalyptus spp. (Cingulata: Glyptodontidae: Hoplophorini): Cranial morphology and palaeoenvironments along the changing Quaternary". Journal of Natural History. 45 (15–16): 893. Bibcode:2011JNatH..45..893Z. doi:10.1080/00222933.2010.536917. S2CID85146482.
↑ Owen, R. (1845). Descriptive and illustrated catalogue of the fossil organic remains of mammalia and aves contained in the museum of the Royal College of Surgeons of England.
↑ Lydekker, R. (1894). Contributions to a knowledge of the fossil vertebrates of Argentina. Taller de publicaciones del Museo.
↑ Ameghino, F. (1920). Sur les édentés fossiles de l’Argentine. Examen critique, révision et correction de l’ouvrage de la MR Lydekker. Obras Completas y Correspondencia Científica, 11, 447-909.
1 2 Ameghino, F. (1889). Contribucion al conocimiento de los mamiferos fosiles de la República Argentina: Obra escrita bajo los auspicios de la Academia nacional de ciencias de la República Argentina para ser presentada á la Exposicion universal de Paris de 1889 (Vol. 6). PE Coni é hijos.
↑ Ameghino, F. (1891). Mamíferos y aves fósiles argentinas. Revista Argentina de Historia Natural, 1.
1 2 Paula Couto, C. D. (1957). Sôbre um gliptodonte do Brasil. Boletim Divisão de Geologia e Mineralogia, 165, 1-37.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Zurita, A. E. (2007). Sistemática y evolución de los Hoplophorini (Xenarthra: glyptodontidae: hoplophorinae. Mioceno tardío-Holoceno temprano) (Doctoral dissertation, Universidad Nacional de La Plata).
↑ Toriño, P. (2015). Nuevos aportes de la sistemática de los" Plohophorini" de Uruguay (Mammalia, cingulata, glyptodontidae).
↑ Asakura, Y., & Oliveira, E. V. (2021). Paleobiology of Hoplophorus euphractus Lund, 1839, a large cingulate from Brazil Intertropical Region. PalZ, 95(2), 359-372.
↑ González, L. R. (2010). Los Cingulata (Mammalia, Xenarthra) del Mioceno temprano y medio de Patagonia (edades santacrucense y “friasense”) (Doctoral dissertation, Universidad Nacional de La Plata (UNLP)).
↑ Zurita, A. E., Carlini, A. A., Scillato-Yané, G. J., & Tonni, E. P. (2004). Mamíferos extintos del Cuaternario de la provincia del Chaco (Argentina) y su relación con aquellos del este de la región pampeana y de Chile. Revista Geológica de Chile, 31(1), 65-87.
↑ Noriega, J. I., Carlini, A. A., & Tonni, E. P. (2004). Vertebrados del Pleistoceno tardío de la cuenca del Arroyo Ensenada (Departamento Diamante, provincia de Entre Ríos). Temas de la Biodiversidad del Litoral fluvial argentino. INSUGEO, Miscelánea, 12, 71-76.
↑ Zurita, A. E., Miño-Boilini, Á. R., Soibelzon, E., Carlini, A. A., & Paredes Rios, F. (2009). The diversity of Glyptodontidae (Xenarthra, Cingulata) in the Tarjia Valley (Bolivia): Systematic, biostratigraphic and paleobiogeographic aspects of a particular assemblage.(With 3 figures and 1 table). Neues Jahrbuch fur Geologie und Palaontologie-Abhandlungen, 251(2), 225.
↑ Chiesa, J., Lucero, N., & Strasser, E. (2005). Sclerocalyptinae en la Depresión de Conlara. San Luis, Argentina, 21, 12-13.
↑ Soibelzon, E., Tonni, E. P., & Bidegain, J. C. (2008). Cronología, magnetoestratigrafía y caracterización bioestratigráfica del Ensenadense (Pleistoceno inferior-medio) en la ciudad de Buenos Aires. Revista de la Asociación Geológica Argentina, 63(3), 421-429.
↑ Cione, A. L., & Tonni, E. P. (1997). Biostratigraphy and chronological scale of upper-most Cenozoic in the Pampean Area, Argentina. In Quaternary of South America and Antarctic Peninsula/Rabassa, Jorge; Salemme, Mónica C..
↑ Quinteros, R. B., Behrensmeyer, A. K., & Ormazábal, G. C. (2004). Paleoclima y evolución faunística en el Plio-Pleistoceno de África y América del Sur. Ameghiniana, 41(4), 641-649.
↑ Fernicola, J. C., Toledo, N., Bargo, M. S., & Vizcaíno, S. F. (2012). A neomorphic ossification of the nasal cartilages and the structure of paranasal sinus system of the glyptodont Neosclerocalyptus Paula Couto 1957 (Mammalia, Xenarthra). Palaeontologia Electronica, 15.
↑ Vizcaíno, S. F., Cassini, G. H., Fernicola, J. C., & Bargo, M. S. (2011). Evaluating habitats and feeding habits through ecomorphological features in glyptodonts (Mammalia, Xenarthra). Ameghiniana, 48(3), 305-319.
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