| Propalaehoplophorus | |
|---|---|
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| Propalaeohoplophorus minor | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Cingulata |
| Family: | Chlamyphoridae |
| Subfamily: | † Glyptodontinae |
| Genus: | † Propalaehoplophorus Ameghino 1887 |
| Species | |
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| Synonyms | |
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Propalaehoplophorus, also written as Propalaeohoplophorus, is an extinct genus of glyptodont, which lived in South America during the Early Miocene epoch. [1]
This animal was to be very similar to the subsequent glyptodonts of the Pliocene and Pleistocene, such as Glyptodon and Panochthus , but was much smaller in size. The total body length of the animal was just under a meter, and the highest point of the carapace was around 50 centimeters high.
The dorsal armor was made up of transversal plaques files but were still present, along the lateral and front margins, two or three rows of osteoderms that indicate slight flexibility. The ornamentation of the plates consisted in a large central -oval figure, surrounded by a row of polygonal peripheral figures. The carapace was short and convex, with 19–20 transverse osteoderms on the midline, which became 27 on the side edges due to two bifurcations. The plates are equipped with clear but shallow furrows, and the central figures are generally flat, even if slightly swollen in the back. Small hair piles were present, located in the points of origin of the radial furrows. The tail was protected by five or six mobile rings, followed by a solid bone tube, probably corresponding to four rings welded together; the tube stopped abruptly, and was closed posteriorly by an irregular plate.
The skull was narrow, but already equipped with the characteristic bone processes descending below the orbit area, typical of the glyptodonts. There was a cephalic shield consisting of 28–29 irregular plates, all separated from each other, by the ornamentation that recalled that of the carapace but less marked. The teeth were not as hypsodont as those of subsequent glyptodonts, and their shape was less symmetrical: the lobes were more enlarged in the outside. The front teeth were still simple. It has been observed in some specimens that two or three dimples were present on the premaxilla and in the front of the jaw, perhaps corresponding to rudimentary incisors fall. The muzzle was still relatively elongated, and the sagittal and occipital ridge were clear. Cranium and carapace of Propalaehoplophorus minor the spine, on the other hand, had already acquired the arched shape and the degree of vertebral fusion typical of the most recent glyptodonts. The rear legs were much longer than the front ones, and the femur was similar to that of the wardrobe, long and relatively slender. The foot was pentadactyl and equipped with toes and large fingers, similar to those of Neosclerocalyptus . The scapula was still relatively high and narrow, while the humerus was like that of armadillos, and had a well-developed deltoid ridge, as well as that for the humerus, and a large foramina. The hand was equipped with pointed claws.
The genus Propalaehoplophorus was described for the first time by Florentino Ameghino in 1887, on the basis of fossil remains found in lower Miocene strata in Argentina; type species is P. australis, which is known from several deposits in Argentina. Another well known species is P. minor, which is also from Argentina. Propalaehoplophorus is the best known member of the Propalaehoplophorini, the group including the oldest definitively known glyptodonts, whose skeleton still preserve more armadillo-like characteristics. Propalaehoplophorus is the eponymous genus of this group and draws its name from the genus Palaehoplophorus , which in turn derives from Hoplophorus , another genus of glyptodont, but it is known from the Pleistocene of Brazil.
Modern cladistic analysis suggests that Propalaehoplophorus is the most basal member of the "Austral clade", more closely related to glyptodonts with fused caudal tube tails like Doedicurus than to Glyptodon.Cladogram after Barasoain et al. 2022 [2] :
| Glyptodonts |
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Fossils of Propalaehoplophorus have been found in the Santa Cruz and Sarmiento Formations of Argentina, the Honda Group and Nazareno Formation of Bolivia and the Río Frías Formation of Chile. [3]
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.
Doedicurus is an extinct genus of glyptodont from North and 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 Brazil, Uruguay, Paraguay, Bolivia, Peru, Argentina, and Colombia. 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.
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.
Neosclerocalyptus was an extinct genus of glyptodont that lived during the Pliocene, Pleistocene, and Holocene of Southern South America, mostly Argentina. It was small compared to many glyptodonts at only around 2 meters long and 360 kilograms.
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.
Prozaedyus is an extinct genus of chlamyphorid armadillo that lived during the Middle Oligocene and Middle Miocene in what is now South America.
Eucinepeltus is an extinct genus of glyptodont. It lived during the Early Miocene, and its fossilized remains were discovered in South America.
Glyptatelus is an extinct genus of glyptodont. It lived from the Late Eocene to the Middle Oligocene in what is now Argentina and Bolivia.
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.
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.
Asterostemma is an extinct genus of glyptodont. It lived during the Middle Miocene, and its fossilized remains were discovered in South America.
Cochlops is an extinct genus of glyptodont. It lived from the Early to Middle Miocene, and its fossilized remains have been found in South America.
The Santa Cruz Formation is a geological formation in the Magallanes/Austral Basin in southern Patagonia in Argentina and in adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with eponymous Santacrucian SALMA. The formation extends from the Andes to the Atlantic coast. In its coastal section it is divided into two members, the lower, fossil rich Estancia La Costa Member, which has a lithology predominantly consisting of tuffaceous deposits and fine grained sedimentary claystone and mudstone, and the upper fossil-poor Estancia La Angelina Member, which consists of sedimentary rock, primarily claystone, mudstone, and sandstone. The environment of deposition is interpreted to have been mostly fluvial, with the lowermost part of the Estancia La Costa Member being transitional between fluvial and marine conditions. The environment of the Estancia La Costa Member is thought to have been relatively warm and humid, but likely became somewhat cooler and drier towards the end of the sequence. The Santa Cruz Formation is known for its abundance of South American native ungulates, as well as an abundance of rodents, xenarthrans, and metatherians.
Peltephilidae is a family of South American cingulates (armadillos) that lived for over 40 million years, but peaked in diversity towards the end of the Oligocene and beginning of the Miocene in what is now Argentina. They were exclusive to South America due to its geographic isolation at the time, one of many of the continent's strange endemic families. Peltephilids are one of the earliest known cingulates, diverging from the rest of Cingulata in the Early Eocene.
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