Pilosans of the Caribbean

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The mammalian order Pilosa, which includes the sloths and anteaters, includes various species from the Caribbean region. Many species of sloths are known from the Greater Antilles, all of which became extinct over the last millennia, but some sloths and anteaters survive on islands closer to the mainland.

For the purposes of this article, the "Caribbean" includes all islands in the Caribbean Sea (except for small islets close to the mainland) and the Bahamas, Turks and Caicos Islands, and Barbados, which are not in the Caribbean Sea but biogeographically belong to the same Caribbean bioregion.

Overview[edit]

Extinct sloths are known from the three Greater Antilles of Cuba, Hispaniola, and Puerto Rico and several smaller Antillean islands, but they are missing from the fourth of the Greater Antilles, Jamaica. These are part of the family Megalonychidae, which also includes some of the extinct giant ground sloths, such as Megalonyx, and the living two-toed sloths (Choloepus) of the American mainland.[1] All Greater Antillean sloths are now extinct; their extinction by ~4400 BP (uncalibrated radiocarbon date) apparently postdated the extinction of the mainland ground sloths by about six thousand years, and coincided (to within a thousand years) with the arrival of humans on the islands.[2][3] The extinct Caribbean sloths apparently had a wide range of locomotor habits corresponding to varying degrees of arboreality, but were generally more terrestrial than extant tree sloths.[4][5] They had been present on the Antilles since the early Oligocene, 32 million years ago.[6] The subdivision of Antillean sloths into several subfamilies implies at least a diphyletic origin for them, requiring two or more separate colonization events.[7]

In addition to the Greater Antillean sloths, some other pilosans are still extant on islands close to the Central and South American mainland. This includes several anteaters and a member of the other sloth family, that of the three-toed sloths, restricted to a small island in Panama.[8] The record of a tamandua from Cozumel, off Mexico, was probably in error.[9]

The genera of Caribbean pilosans are classified as follows:[10]

Cuba[edit]

Cuba is the largest of the Greater Antilles. A diverse assortment of sloths is known.

  • Acratocnus antillensis (previously Miocnus antillensis), a sloth known exclusively from Cuba. Isolated femora referred to separate species Habanocnus hoffstetteri and H. paulacoutoi fall within the range of variation of this species.[11]
  • Galerocnus jaimezi, a sloth.[12]
  • Imagocnus zazae, a large sloth from the early Miocene fauna of Domo de Zaza. Although it is recognizably megalonychid, its precise relations are obscure. A large pelvis found at Domo de Zaza may indicate the presence of another, even larger sloth; alternatively, I. zazae may have been variable in size.[13]
  • Neocnus gliriformis (previously Microcnus gliriformis), a sloth found only on Cuba.[14]
  • Megalocnus rodens, a common sloth in faunas from western and central Cuba.[15] It has been radiocarbon-dated to about 6000 years before present.[16]
  • Neocnus major, also known from Cuba alone. It includes the previously recognized N. minor and N. baireiensis and may not itself be distinct from N. gliriformis.[17]
  • Paramiocnus riveroi, a large and possibly arboreal sloth known from limited remains.[18]
  • Parocnus browni (previously Mesocnus browni), a sloth related to Hispaniolan P. serus. The previously recognized species Mesocnus torrei and Mesocnus herrerai are now regarded as identical to P. browni.[19] Remains of P. browni have been radiocarbon-dated to about 5000 years before present.[16]

Hispaniola[edit]

Hispaniola, the second largest of the Greater Antilles, is divided into Haiti and the Dominican Republic. It has a diverse sloth fauna.

  • Acratocnus simorhynchus, a sloth from eastern Hispaniola known from remains dated to about 20,000 years before present.[20]
  • Acratocnus ye, a sloth known only from Hispaniola.[21]
  • Megalocnus zile, a sloth known from both Hispaniola and the satellite island of Tortuga, apparently much rarer than its Cuban relative M. rodens.[22]
  • Neocnus comes (previously Acratocnus comes and Synocnus comes), a large Neocnus commonly found in cave deposits throughout Hispaniola.[23] Several remains have been radiocarbon-dated, the youngest to about 5,000 years before present.[24]
  • Neocnus dousman, a medium-sized Neocnus found throughout Hispaniola.[25] A single radiocarbon-dated specimen is about 10,000 years old.[24]
  • Neocnus toupiti, a small Neocnus and perhaps the smallest sloth known, found in Haiti.[26]
  • Parocnus serus, a sloth known from Hispaniola and the satellite islands of Tortuga and Gonâve.[27] A specimen has been radiocarbon-dated to over 14,000 years before present.[24]

Tortuga[edit]

Tortuga is an island off northern Haiti.

Gonâve[edit]

Gonâve is an island off southwestern Haiti.

Puerto Rico[edit]

Only one sloth is known from the Quaternary of Puerto Rico, the easternmost of the Greater Antilles; another species is known from much older, Oligocene, sediments.

  • Acratocnus odontrigonus, a sloth known only from Puerto Rico. Acratocnus major, described on the basis of somewhat larger Puerto Rican sloth bones, simply represents large individuals of A. odontrigonus.[28]
  • A small sloth femur has been found at an early Oligocene site in southwestern Puerto Rico. It is not sufficiently diagnostic to permit conclusive identification as a megalonychid.[29]

Grenada[edit]

Grenada is the southernmost island of the main Lesser Antillean island arc.

  • Three teeth of a sloth have been found in a late Pliocene or early Pleistocene deposit that also yielded the capybara Hydrochoerus gaylordi. The teeth differ in size and may represent either one or two species and although recognizably megalonychid, their precise relationships cannot be determined.[30]

Trinidad[edit]

Trinidad is a large island off northeastern Venezuela. It hosts two species of anteaters that are also found on mainland South America.

Curaçao[edit]

Curaçao is a Dutch island off northwestern Venezuela.

Escudo de Veraguas[edit]

Escudo de Veraguas is an island off northern Panama. Despite its small size, it supports two mammal species found nowhere else: the bat Artibeus incomitatus and the only extant Caribbean sloth.[34]

Related articles[edit]

References[edit]

  1. ^ White and MacPhee, 2001
  2. ^ Steadman et al., 2005
  3. ^ Cooke et al., 2017
  4. ^ White, 1993
  5. ^ Steadman et al., 2005, p. 11767
  6. ^ White and MacPhee, 2001, p. 201
  7. ^ White and MacPhee, 2001, p. 227
  8. ^ Gardner, 2005
  9. ^ Jones and Lawlor, 1965, p. 414
  10. ^ Gardner, 2005; White and MacPhee, 2001, table 2
  11. ^ White and MacPhee, 2001, pp. 214–215
  12. ^ Arredondo and Rivero, 1997
  13. ^ White and MacPhee, 2001, pp. 224–225
  14. ^ White and MacPhee, 2001, pp. 217–218
  15. ^ White and MacPhee, 2001, pp. 221–222
  16. ^ a b Steadman et al., 2005, p. 11765
  17. ^ White and MacPhee, 2001, p. 218
  18. ^ Arredondo and Arredondo, 2000
  19. ^ White and MacPhee, 2001, pp. 223–224
  20. ^ Rega et al., 2001
  21. ^ White and MacPhee, 2001, p. 215
  22. ^ a b White and MacPhee, 2001, p. 222
  23. ^ White and MacPhee, 2001, pp. 218–219
  24. ^ a b c Steadman et al., 2005, p. 11766
  25. ^ White and MacPhee, 2001, p. 219
  26. ^ White and MacPhee, pp. 219–220
  27. ^ a b c White and MacPhee, 2001, p. 223
  28. ^ White and MacPhee, 2001, pp. 213–214
  29. ^ White and MacPhee, 2001, p. 225
  30. ^ MacPhee et al., 2000
  31. ^ Gardner, 2005, p. 102
  32. ^ Gardner, 2005, p. 103
  33. ^ White and MacPhee, 2001, pp. 216–217
  34. ^ a b Anderson and Handley, 2001

Literature cited[edit]