Thylophorops

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Thylophorops
Temporal range: Pliocene (Huayquerian-Uquian)
~5–2.6  Ma
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Thylophorops lorenzinii.jpg
Adult and juvenile T. lorenzinii compared to Didelphis crucialis
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Didelphimorphia
Family: Didelphidae
Subfamily: Didelphinae
Genus: Thylophorops
Ameghino, 1908
Type species
Thylophorops chapadmalensis
Ameghino,1908
Species
  • Thylophorops chapadmalensis
  • Thylophorops lorenzinii
  • Thylophorops perplana/perplanus

Thylophorops is an extinct genus of didelphine opossums from the Pliocene of South America. Compared to their close didelphine cousins like the living Philander and Didelphis (and like the still living Lutreolina ) opossums, Thylophorops displays specialization towards carnivory, and one species, T. lorenzinii, is the largest known opossum of all time, [1] which could imply a macropredatory role. [2] [3]

Contents

Taxonomy

Thylophorops is rather consistently recovered as a didelphine opossum, most often compared to and usually falling within the Didelphis , Philander and Lutreolina group. [4] Within Thylophorops itself, there are three recognized species:

Biology

Thylophorops species (as well as several other contemporary opossum genera [3] ) show a high degree of speciation towards carnivory compared to most living didelphines. Their premolar and molar teeth were proportionally larger than those of living opossums and their grinding facets imply a more dedicated shearing action; these have been interpreted as "omnivory leading towards carnivory" [1] and as more specialized carnivory in posterior studies. [2] [3] There is evidence that T. chapadmalensis re-appropriated burrows from other digging mammals, as well as outright consuming them. Thylophorops species as a whole tended to be terrestrial rather than arboreal. [3]

Paleoecology

Thylophorops lived at a time when South America's older predatory guilds were dismantling. It co-existed with only a few sparassodont and phorusrhacid taxa like Thylacosmilus and Llallawavis , [2] [3] and it, as well as similar opossum species, evolved to fill the ecological blanks. A similar case is observed with the carnivorous armadillo Macroeuphractus , a product of this same era of faunal turn-overs. [2]

As mentioned above, there is evidence of T. chapadmalensis predating on contemporary caviomorphs and appropriating burrows, from them or other mammals such as armadillos. [3]

Related Research Articles

Opossum Family of mammals

The opossum is a marsupial of the order Didelphimorphia endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 103 or more species in 19 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of the two continents. Their unspecialized biology, flexible diet, and reproductive habits make them successful colonizers and survivors in diverse locations and conditions.

White-bellied woolly mouse opossum species of mammal

The white-bellied woolly mouse opossum is a small pouchless marsupial of the family Didelphidae. It was formerly assigned to the genus Micoureus, which was made a subgenus of Marmosa in 2009. The specific epithet was given in honour of Constance Sladen, wife of the naturalist Percy Sladen. She funded the 1902 expedition which collected the type specimen.

Cingulata order of mammals

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.

<i>Didelphis</i> genus of mammals

Didelphis is a genus of New World marsupials. The six species in the genus Didelphis, commonly known as large American opossums, are members of the order Didelphimorphia. The genus is composed of cat-sized omnivorous species, which can be recognized by their prehensile tails and their tendency to feign death when cornered. The largest species, the Virginia opossum, is the only marsupial to be found in North America north of Mexico.

Sparassodonta extinct order of mammals

Sparassodonta is an extinct order of carnivorous metatherian mammals native to South America. They were once considered to be true marsupials, but are now thought to be either a sister taxon to them, or considerably distantly related, part of a separate clade of Gondwanan metatherians. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pliocene Great American Interchange, but more recent research has showed that sparassodonts died out long before eutherian carnivores arrived in South America. Sparassodonts have been referred to as borhyaenoids by some authors, but currently the term Borhyaenoidea refers to a restricted subgroup of sparassodonts comprising borhyaenids and their close relatives.

Bushy-tailed opossum species of mammal

The bushy-tailed opossum is an opossum from South America. It was first described by English zoologist Oldfield Thomas in 1912. It is a medium-sized opossum characterized by a large, oval, dark ears, fawn to cinnamon coat with a buff to gray underside, grayish limbs, and a furry tail. Little is known of the behavior of the bushy-tailed opossum; less than 25 specimens are known. It appears to be arboreal (tree-living), nocturnal and solitary. The diet probably comprises insects, eggs and plant material. This opossum has been captured from heavy, humid, tropical forests; it has been reported from Bolivia, Brazil, Colombia, Ecuador and Peru. The IUCN classifies it as least concern.

Gray four-eyed opossum species of mammal

The gray four-eyed opossum is an opossum species from Central and South America, ranging from southern Mexico to Peru, Bolivia and southwestern Brazil, at altitudes from sea level to 1600 m, but generally below 1,000 metres (3,300 ft). Its habitats include primary, secondary and disturbed forest. It is one of many opossum species in the order Didelphimorphia and the family Didelphidae.

White-eared opossum species of mammal

The white-eared opossum is an opossum species found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. It is a terrestrial and, sometimes, arboreal animal, and a habitat generalist, living in a wide range of different habitats.

Bare-tailed woolly opossum species of mammal

The bare-tailed woolly opossum is an opossum from South America. It was first described by Swedish zoologist Carl Linnaeus in 1758. The bare-tailed woolly opossum is characterized by a gray head, brown to gray coat, orange to gray underside and a partially naked tail. It is nocturnal and solitary; there is hardly any social interaction except between mother and juveniles and in mating pairs. The opossum constructs nests in tree cavities, and its litter size ranges from one to seven. Gestation lasts 25 days, and the juveniles exit the pouch after three months; weaning occurs a month later. The bare-tailed woolly opossum inhabits subtropical forests, rainforests, secondary forests, and plantations; its range extends from northern Venezuela to northeastern and southcentral Brazil. The IUCN classifies this opossum as least concern.

Lutrine opossum species of mammal

The lutrine opossum, also known as the little water opossum, thick-tailed opossum, or coligrueso is an opossum species from South America in the genus Lutreolina.

Short-tailed opossum genus of mammals

Monodelphis is a genus of marsupials in the family Didelphidae, commonly referred to as short-tailed opossums. They are found throughout South America. As of January 2019, the most recently described species is M. vossi.

Gray and black four-eyed opossum genus of mammals

The seven species in the genus Philander, commonly known as gray and black four-eyed opossums, are members of the order Didelphimorphia. Mature females have a well-developed marsupium. The tail appears to be hairless except for the proximal 5 or 6 cm, which has a few long hairs. The tail is slightly longer than the head-and-body length, and it is black for the proximal one half to two thirds of its length. The genus is closely related to Didelphis but the species of Philander are smaller than those of Didelphis. The genus formerly included Metachirus nudicaudatus, but this species lacks a pouch and so is now considered a separate genus. The common name comes from the white spots above the eyes, which can appear from a distance to be another set of eyes.

<i>Doedicurus</i> An extinct genus of mammals belonging to the armadillo order, Cingulata

Doedicurus, or Dædicurus, 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 order 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.

<i>Chapalmalania</i> genus of mammals

Chapalmalania is an extinct genus of procyonid from the Pliocene of Argentina and Colombia.

Yellow-sided opossum species of mammal

The yellow-sided opossum is an opossum species from South America. It is found in Argentina, Brazil and Uruguay. They have grey or black fur on their dorsal side with yellowish fur on the lateral side that continues down to the feet. They are the most mysterious of all the Monodelphis that is found specifically in the Pampean region or Pampa of Argentina. It is suspected to be a once-in-a-lifetime breeder as seen in a three-year observational study of one population in the marshy grasslands of the Pampean region. Maintaining their native grasslands is important for them to keep a stable population. They show sexual dimorphism in overall size: adult males are typically 100-150 g whereas adult females are 30-70 g.

Elegant fat-tailed mouse opossum species of mammal

The elegant fat-tailed mouse opossum, also known as the Chilean mouse opossum, is an opossum from central Chile. The type species of Thylamys, it was first described by English naturalist George Robert Waterhouse in 1839. This medium-sized opossum is characterized by black rings around the eyes, white limbs, gray to light brown coat, lighter flanks and underbelly and a thick 12.7–14.6 centimetres (5.0–5.7 in) long tail covered with hairs. It is crepuscular and lives in nests in tree hollows or under rocks and roots. This opossum feeds mainly on arthropods and larvae apart from fruits. Litter size is typically between 11 and 13. The elegant fat-tailed opossum can occur in a variety of habitats – from cloud forests to chaparrals. The IUCN classifies the opossum as least concern.

<i>Thylamys</i> genus of mammals

Thylamys is a genus of opossums in the family Didelphidae. The premaxillae are rounded rather than pointed. The females lack a pouch. The females' nipples are arranged in two symmetrical rows on the abdomen. All species but T. macrurus store fat in their tails., although this is not necessarily true for all species in the genus. Fossils belonging to the genus date back to the Miocene, with the oldest specimens being found in the Cerro Azul Formation of Argentina and the Honda Group of Colombia. Genetic studies indicate that the genus may have originated around 14 million years ago.

Pampatheriidae Family of extinct armadillo-like grazing mammals

Pampatheriidae is an extinct family of large plantigrade armored xenarthrans related to armadillos. However, pampatheriids have existed as a separate lineage since at least the middle Eocene Mustersan age, 45 to 48 million years ago. Pampatheres evolved in South America during its long period of Cenozoic isolation. Although widespread, they were less diverse and abundant than the armadillos. Holmesina spread to North America after the formation of the Isthmus of Panama as part of the Great American Interchange. They finally disappeared on both continents in the end-Pleistocene extinctions, about 12,000 years ago.

Cyonasua is an extinct genus of procyonid from the Late Miocene to Middle Pleistocene of South America. Fossils of Cyonasua have been found in Argentina, Bolivia, Uruguay, and Venezuela. The oldest well-dated fossils of Cyonasua are approximately 7.3 million years old. Most fossils of Cyonasua are late Miocene to early late Pliocene in age, but a single early Pleistocene specimen indicates that members of this genus survived until at least 0.99 million years ago.

<i>Macroeuphractus</i> An extinct genus of mammals belonging to the armadillo order of xenarthrans

Macroeuphractus is a genus of extinct armadillos from the Late Miocene to Late Pliocene of South America. The genus is noted for its large size, with Macroeuphractus outesi being the largest non-pampathere or glyptodont armadillo discovered, as well as its specializations for carnivory, unique among all xenarthrans.

References

  1. 1 2 3 4 Goin, F.J.; Zimicz, N.; De Los Reyes, M.; Soibelzon, L. (2009). "A new large didelphid of the genus Thylophorops (Mammalia: Didelphimorphia: Didelphidae), from the late Tertiary of the Pampean Region (Argentina)". Zootaxa. 2005 (1): 35–46. doi:10.11646/zootaxa.2005.1.3.
  2. 1 2 3 4 Prevosti, F.J.; Forasiepi, A.; Zimicz, N. (2011). "The Evolution of the Cenozoic Terrestrial Mammalian Predator Guild in South America: Competition or Replacement?". Journal of Mammalian Evolution. 20 (1): 3–21. doi:10.1007/s10914-011-9175-9. S2CID   15751319.
  3. 1 2 3 4 5 6 Cenizo, M.; Soibelzon, E.; Saffer, M.M. (October 2015). "Mammalian predator–prey relationships and reoccupation of burrows in the Pliocene of the Pampean Region (Argentina): new ichnological and taphonomic evidence". Historical Biology. 28 (8): 1026–1040. doi:10.1080/08912963.2015.1089868. S2CID   83862150.
  4. M. C. McKenna and S. K. Bell. 1997. Classification of Mammals Above the Species Level 1-640
  5. Zimicz, N. (2014). "Avoiding Competition: the Ecological History of Late Cenozoic Metatherian Carnivores in South America". Journal of Mammalian Evolution. 21 (4): 383–393. doi:10.1007/s10914-014-9255-8. S2CID   10161199.
  6. Goin, Francisco J.; Ulyses F. J. Pardinas (1996). "Revision de las especies del genero Hyperdidelphys Ameghino, 1904 (Mammalia, Marsupialia, Didelphidae. Su significacion filogenetica, estratigrafica y adaptativa en el Neogeno del Cono Sur sudamericano". Estudios Geologicos. 52 (5–6): 327–359. doi:10.3989/egeol.96525-6275.