Jamaican Monkey
Encyclopedia
The Jamaican Monkey is an extinct
species
of monkey
first uncovered at Long Mile Cave
in Jamaica
by Harold Anthony in 1919. Anthony is responsible for many species descriptions of Caribbean taxa during this period and his field notes
record the discovery of the monkey material:
The eventual species description was not completed until 1952 when two graduate students
, Ernest Williams and Karl Koopman, found the associated femur and mandibular fragment forgotten in a drawer at the American Museum of Natural History
. They remained circumspect in placing this primate taxonomically as it had shared characteristics with a number of platyrrhine taxa.
of 2 incisor
s, 1 canine
, 3 premolar
s and 2 molars – a departure from the vast majority of living platyrrhines, with the notable exception of the callitrichines. It is significantly larger than the living callitrichines, and work by Rosenberger has largely eliminated the possibility that these taxa share a close phylogenetic relationship
. Rosenberger suggested that the absence of the third molar in Xenothrix was not homologous
with this character state in callitrichines. He based his assessment on the length of the molars relative to the molar row, and the inferred retention of hypocones on M1-2, which have been greatly reduced in the marmoset
s and tamarin
s. He further suggested that Xenothrix shared a close phylogenetic affinity with Callicebus or Aotus. His conclusions were tentative due to the fragmentary nature of the material.
The postcranial remains discovered by Anthony in the 1920’s were eventually described by MacPhee and Fleagle who attributed the femur, os coxae
, and tibia
to the order Primates. MacPhee and Fleagle stated that the primate postcrania bore little resemblance to modern forms, but they interpreted the femur as being indicative of slow climbing. Interestingly, the femur also shares some similarities with Potos flavus, the kinkajou
. They provisionally accepted Hershkovitz’s family Xenotrichidae until further analysis could fully elucidate the relationships of Xenothrix.
, first proposed by MacPhee et al., that all the Antillean monkeys (the others being the two Cuban monkey
species of genus Paralouatta and Antillothrix bernensis of Hispaniola
) belonged to a monophyletic group linked most closely with modern Callicebus.
Rosenberger has objected to this hypothesis and has suggested that Xenothrix was a Jamaican owl monkey
, thus modifying his earlier view. He based his conclusions on the fairly large orbit size as inferred from the preserved orbital rim, large inferior orbital fissure
, and the large I1 alveolus as compared to the I2 alveolus. These characters are shared with Aotus. MacPhee and Horovitz tested this alternative phylogeny with extensive anatomical comparisons and by extending their parsimony analysis using PAUP*. They maintained that the monophyly of the Antillean monkeys was still supported in the most parsimonious trees, but in slightly less parsimonious trees, Aotus does appear to be linked with Xenothrix. MacPhee and Horovitz assigned the Antillean monkeys to the tribe Xenotrichini – the sister group
of the tribe Callicebini.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
first uncovered at Long Mile Cave
Long Mile Cave
Long Mile Cave, sometimes known locally as Pick'ny Mama Cave or Hell's Gate Cave, is a palaeontological and palaeoanthropological site in the Cockpit Country of north-western Jamaica.-Description:...
in Jamaica
Jamaica
Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
by Harold Anthony in 1919. Anthony is responsible for many species descriptions of Caribbean taxa during this period and his field notes
Fieldnotes
Fieldnotes refer to various notes recorded by scientists during or after their observation of a specific phenomenon they are studying. Fieldnotes are particularly valued in descriptive sciences such as ethnography, biology, geology, and archaeology, each of which have long traditions in this...
record the discovery of the monkey material:
“January 17 – Spent all day digging in the long mile cave and secured some good bones. The most important find was the lower jawMandibleThe mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
and femurFemurThe femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
of a small monkey, found in the yellow limestoneLimestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
detritus. It was not associated with the human remains but not so far from them that the animal must not be strongly suspected as an introduced speciesIntroduced speciesAn introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. It was deeper than any of the human bones by at least 10” to 1’…” (reproduced in Williams and Koopman, 1952)
The eventual species description was not completed until 1952 when two graduate students
Graduate school
A graduate school is a school that awards advanced academic degrees with the general requirement that students must have earned a previous undergraduate degree...
, Ernest Williams and Karl Koopman, found the associated femur and mandibular fragment forgotten in a drawer at the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
. They remained circumspect in placing this primate taxonomically as it had shared characteristics with a number of platyrrhine taxa.
Analysis
The small mandible has a dental formulaDentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...
of 2 incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s, 1 canine
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
, 3 premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
s and 2 molars – a departure from the vast majority of living platyrrhines, with the notable exception of the callitrichines. It is significantly larger than the living callitrichines, and work by Rosenberger has largely eliminated the possibility that these taxa share a close phylogenetic relationship
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
. Rosenberger suggested that the absence of the third molar in Xenothrix was not homologous
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
with this character state in callitrichines. He based his assessment on the length of the molars relative to the molar row, and the inferred retention of hypocones on M1-2, which have been greatly reduced in the marmoset
Marmoset
Marmosets are the 22 New World monkey species of the genera Callithrix, Cebuella, Callibella, and Mico. All four genera are part of the biological family Callitrichidae. The term marmoset is also used in reference to the Goeldi's Monkey, Callimico goeldii, which is closely related.Most marmosets...
s and tamarin
Tamarin
The tamarins are squirrel-sized New World monkeys from the family Callitrichidae in the genus Saguinus. They are closely related to the lion tamarins in the genus Leontopithecus.- Range :...
s. He further suggested that Xenothrix shared a close phylogenetic affinity with Callicebus or Aotus. His conclusions were tentative due to the fragmentary nature of the material.
The postcranial remains discovered by Anthony in the 1920’s were eventually described by MacPhee and Fleagle who attributed the femur, os coxae
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, and tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
to the order Primates. MacPhee and Fleagle stated that the primate postcrania bore little resemblance to modern forms, but they interpreted the femur as being indicative of slow climbing. Interestingly, the femur also shares some similarities with Potos flavus, the kinkajou
Kinkajou
The kinkajou , also known as the honey bear , is a rainforest mammal of the family Procyonidae related to olingos, coatis, raccoons, and the ringtail and cacomistle. It is the only member of the genus Potos. Kinkajous may be mistaken for ferrets or monkeys, but are not closely related...
. They provisionally accepted Hershkovitz’s family Xenotrichidae until further analysis could fully elucidate the relationships of Xenothrix.
Further research
In the 1990s, several expeditions to Jamaican cave sites resulted in the recovery of additional cranial and postcranial material attributed to Xenothrix, including a partial lower face containing the palate with left and right P4-M2, most of the maxilla and parts of the sphenoid. This discovery confirmed that the dental formula of this taxon is 2.1.3.2. With the new partial face, Horovitz and MacPhee were able to further develop the hypothesisHypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
, first proposed by MacPhee et al., that all the Antillean monkeys (the others being the two Cuban monkey
Cuban Monkey
Paralouatta is a platyrrhine genus that currently contains two extinct species of small primates that lived on the island of Cuba.The Cuban fossil primate, Paralouatta varonai was described from a nearly complete cranium from the late Quaternary in 1991. This cranium and a number of isolated teeth...
species of genus Paralouatta and Antillothrix bernensis of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
) belonged to a monophyletic group linked most closely with modern Callicebus.
Rosenberger has objected to this hypothesis and has suggested that Xenothrix was a Jamaican owl monkey
Night monkey
The night monkeys, also known as the owl monkeys or douroucoulis, are the members of the genus Aotus of New World monkeys . They are widely distributed in the forests of Central and South America, from Panama south to Paraguay and northern Argentina...
, thus modifying his earlier view. He based his conclusions on the fairly large orbit size as inferred from the preserved orbital rim, large inferior orbital fissure
Inferior orbital fissure
Not to be confused with the infraorbital groove, infraorbital canal, and infraorbital foramen.The lateral wall and the floor of the orbit are separated posteriorly by the inferior orbital fissure which transmits the maxillary nerve and its zygomatic branch, and the ascending branches from the...
, and the large I1 alveolus as compared to the I2 alveolus. These characters are shared with Aotus. MacPhee and Horovitz tested this alternative phylogeny with extensive anatomical comparisons and by extending their parsimony analysis using PAUP*. They maintained that the monophyly of the Antillean monkeys was still supported in the most parsimonious trees, but in slightly less parsimonious trees, Aotus does appear to be linked with Xenothrix. MacPhee and Horovitz assigned the Antillean monkeys to the tribe Xenotrichini – the sister group
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
of the tribe Callicebini.
Further reading
- Rosenberger, A.L. (1977). Xenothrix and Ceboid Phylogeny. Journal of Human Evolution, 6: 461-481.
- Rosenberger, A.L. (1981). Systematics: the higher taxa. In Coimbra, A.F. & Mittermeier , R.A. (eds.) Ecology and Behavior of Neotropical Primates 1: 9-28. Rio de Janeiro: Academia Brasileira de Ciencias.
External links
- CREO - Recently extinct species : Xenothrix mcgregori Jamaican monkey (Downloaded:2008-03-30)