Anthropoidea

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Anthropoidea

[‚an·thrə′pȯid·ē·ə]
(vertebrate zoology)
A suborder of mammals in the order Primates including New and Old World monkeys.

Anthropoidea

 

(also Simia), a suborder of mammals of the order Primates. It is divided into two groups: the Platyrrhina and the Catarrhina. The first group includes one superfamily, Ceboidea, which embraces two families—Callithricidae and Cebidae. The second group contains two superfamilies: Cercopithecoidea, which comprises the single family Cercopithecidae, and Hominoidea, which embraces the families Hylobatidae and Anthropomorphidae. The family Hominidae (man) is included in the superfamily Hominoidea. [This article deals principally with all Anthropoidea except man.]

In most platyrrhines, the nasal septum is broad, and the nostrils are placed far apart and turn outward. Catarrhines are characterized by a narrower nasal septum and by nostrils that are turned downward (as in man).

Anthropoidea weigh between 400 g (marmosets) and 180 kg or greater (gorillas). The length of the head and trunk ranges from 15 cm (pygmy marmosets) to 2 m (gorillas). Depending on the species, the tail is longer than the body (howler monkeys, spider monkey, guenons), shorter than the body (ukaris, gelada), or equal in length to the body (capuchins, sacred baboons, Macaca fascicularis). Spider monkeys and howler monkeys have a prehensile tail; the tip of the tail’s naked underside is covered by sensitive cutaneous ridges. The Anthropomorphidae and Barbary apes are tailless; pig-tailed apes, mandrills, and the pig-tailed langur have very short tails.

The well-developed front and hind limbs in most Anthropoidea are almost equal in length. In some species, the front limbs are somewhat shorter than the hind ones (some marmosets and leaf monkeys, guerezas); in others, the forelimbs are considerably longer (Anthropomorphidae and spider monkeys). The limbs are five-digited, prehensile, and adapted to arboreal life. In catarrhines the thumb has greater opposability than in platyrrhines. The thumb of platyrrhines is not opposable (Hapalidae) or is slightly opposable (Cebidae). In some species (guereza, spider monkeys, and woolly spider monkeys), the thumb is reduced to a tubercle or is completely absent; in some Anthropomorphidae, the thumb is reduced. The big toe is developed in all species and is capable of moving to the side. The toes and fingers have nails; the nails of the Hapalidae are clawlike.

The thick pelage of Anthropoidea is sometimes particularly long on certain parts of the body, forming a crest, whiskers, a beard, or tassels on the ears. As a rule, the face and the concha auriculae are hairless. The majority of the Cercopithecoidea have ischial callosities, that is, bare patches of thickened, roughened skin, which are usually brightly colored. Many species have brilliantly colored hairy coats (lion-headed marmoset, mandrill, guereza, douc, marmosets).

The Anthropoidea have a rounded head, and the face in some species is elongated (like a canine muzzle). The nose is well developed only in proboscis monkeys; it is developed to a lesser degree in Rhinopithecus and Simias. The skull size and the ratio of the measurements of the cranium and facial part vary greatly. The eye sockets are directed forward and are completely separated from the temporal fossa by the bony septum, which is incomplete only in nocturnal species. The skulls of large adult Anthropomorphidae have bony ridges to which the powerful masticatory musculature is attached; the facial musculature is well developed and differentiated.

The dental system in Anthropoidea, as in man, is diphyodont (having two sets of teeth—milk teeth and permanent teeth) and heterodontic. It consists of incisors (i), canines (c), premolars (pm), and molars (m). The dental formula for each half of the upper and lower jaws in Hapalidae is 2i, lc, 3pm, and 2m (total of 32 teeth), in Cebidae 2i, 1c, 3pm, and 3m (total of 36), and in all catarrhines 2i, 1c, 2pm, and 3m (total of 32). The premolars of the upper jaw usually have two roots, while the first and second molars have three. In the lower jaw the premolars have one root, and the molars have two.

Most Anthropoidea have a stomach of simple construction; only the leaf monkeys, which are herbivorous, have complex stomachs. All members of the suborder have a cecum; only the Anthropomorphidae have a vermiform appendix. Cheek pouches characterize only the Cercopithecoidea (except for the leaf monkeys). There is one pair of mammary glands on the chest. The uterus is simple, and the placenta is discoid.

The brain in Anthropoidea is relatively large; in all members of the order except the Hapalidae, it has many sulci and is richly convoluted. The large hemispheres usually cover the cerebellum. Reduction of the olfactory apparatus and of the corresponding areas of the brain (rhinencephalon) is characteristic; also reduced are the special tactile hairs, or vibrissae, on the face, which are represented only by two or three pairs (supraorbital, maxillary, and genial). The palms and soles are completely covered with tactile cutaneous ridges and patterns. Only Saguinus oedipus and nocturnal species have areas of skin that are not ridged. The best-developed sense organs are those of hearing and, especially, of sight. Diurnal members of the suborder have binocular, color vision. The retina has a yellow spot and a central fovea; the optic nerves, as in man, partially cross over at the optic chiasm.

In contrast to those in man, the vocal cords of other Anthropoidea lack the constrictive muscles necessary for modulating sounds. A laryngeal sac, often unpaired, affects the resonance and modulation of sounds; in howler monkeys, the sac is located in the hyoid bone.

Most Anthropoidea are diurnal herd animals (except nocturnal platyrrhines). They are predominantly arboreal; however, baboons, geladas, and Barbary apes are strictly terrestrial. The Anthropoidea feed on fruits, leaves, young shoots, insects, snails, birds’ eggs, and small birds. Their principal enemies are snakes, predatory birds (Philippine monkey-eating eagle), leopards, and crocodiles. Members of the suborder reproduce year-round. Gestation in lower Anthropoidea (all platyrrhines and Cercopithecoidea) lasts four or five months. The gestation period is 210 days in Hylobatidae and 235 to 275 days in large Anthropomorphidae. As a rule, one offspring is born (in marmosets, two or three), which stays close to the mother for a lengthy period of time. The lower Anthropoidea attain sexual maturity at three to five years of age, and Anthropomorphidae at seven to ten years of age or later. The life-span of small Anthropoidea reaches 20 to 25 years; large species live 40 years or more. The potential life-span of large Anthropomorphidae is 50 to 60 years.

Monkeys and apes are captured for zoos and laboratories. Since they are the most closely related animals to man, they are particularly important as objects of biological and medical experiments. The animals are used to study a number of human diseases (for example, poliomyelitis) and to find ways of treating them. Owing to the decrease in their numbers, many species (lion-headed marmoset, olive guereza, orangutan, pygmy chimpanzee, gorilla) are protected.

Origin. Anthropoidea probably originated from fossil tarsiers (Tarsiidae) of the Paleocene and Eocene in North America and of the Eocene in Europe. It is conjectured that the platyrrhines, whose ancestors penetrated South America from North America, developed independently from the catarrhines. In the Miocene and Pliocene, Anthropoidea were widely distributed in Europe, Asia, and Africa. Miocene Dryopithecinae, as the common ancestors of man and present-day Anthropomorphidae, are of particular anthropogenetic interest. Higher anthropomorphic Anthropoidea flourished in the Pliocene and the early Pleistocene. A possible ancestor of the earliest humans was a species of terrestrial biped higher Anthropoidea, which was morphologically close to the African Australopithecus and which used natural objects as tools.

REFERENCES

Weber, M. Primaty: Anatomiia, sistematika i paleontologiia lemurov, dolgopiatov i obez’ian. Moscow-Leningrad, 1936. (Translated from German.)
Nesturkh, M. F. Primatologiia i antropogenez. (Obez’iany, poluobez’iany i proiskhozhdenie cheloveka.) Moscow, 1960.
Schaller, G. B. God pod znakom gorilly. Moscow, 1968. (Translated from English.)
Zhizn’ zhivotnykh, vol. 6. Moscow, 1971.
Sanderson, J. T., and G. Steinbacher. Knaurs Affenbuch. Munich-Zürich, 1957.
Sanderson, J. T. Living Mammals of the World, 3rd ed. New York, 1961.
Napier, J. R., and P. H. Napier. A Handbook of Living Primates. London-New York, 1967.
Lawick-Goodall, J. van. In the Shadow of Man. Boston, 1971.

T. D. GLADKOVA