Haplorhini

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Haplorhines[1]
Temporal range: Early Eocene – Recent
Totenkopfaeffchen.jpg
Common squirrel monkey (Saimiri sciureus)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
(unranked): Euprimates
Suborder: Haplorrhini
Pocock, 1918
Subgroups

Simiiformes (monkeys & apes)
Tarsiiformes (tarsiers)

The haplorhines, the "dry-nosed" primates (the Greek name means "simple-nosed"), are members of the clade Haplorhini: the tarsiers and the anthropoids. The anthropoids are the catarrhines (Old World monkeys and apes, including humans) and the platyrrhines (New World monkeys).

The omomyids are an extinct group of prosimians, believed to be more closely related to the tarsiers than to any strepsirrhines, and are considered the most primitive haplorhines.

Haplorhines share a number of derived features that distinguish them from the strepsirrhine "wet-nosed" primates (whose Greek name means "curved nose"), the other suborder of primates from which they parted in evolution some 63 million years ago. The haplorhines, including tarsiers, have all lost the function of the terminal enzyme which manufactures vitamin C, while the strepsirrhine prosimians, like most other orders of mammals, have retained this enzyme and the ability to manufacture vitamin C.[2] The haplorhine upper lip, which has replaced the ancestral rhinarium found in strepsirrhines, is not directly connected to their nose or gum, allowing a large range of facial expressions. Their brain to body ratio is significantly greater than the strepsirrhines, and their primary sense is vision. Haplorhines have a postorbital plate, unlike the postorbital bar found in strepsirhines. Most species are diurnal (the exceptions being the tarsiers and the night monkeys).

All anthropoids have a single-chambered uterus; tarsiers have a bicornate uterus like the strepsirrhines. Most species typically have single births, although twins and triplets are common for marmosets and tamarins. Despite similar gestation periods, haplorhine newborns are relatively much larger than strepsirrhine newborns, but have a longer dependence period on their mother. This difference in size and dependence is credited to the increased complexity of their behavior and natural history.

Etymology[edit]

The taxonomic name Haplorhini derives from the Ancient Greek haploûs (ἁπλούς, "onefold, single, simple") and rhinos (ῥινός, "nose"). It refers to the lack of a rhinarium or "wet nose", which is found in many mammals, but also in strepsirrhine primates.[3]

Classification and evolution[edit]

Haplorhini and its sister clade, Strepsirrhini ("wet-nosed" primates), parted ways about 63 million years ago (mya). Approximately 5 million years later (58 mya), only a short time afterward from an evolutionary perspective, the infraorder Tarsiiformes, whose only remaining family is that of the tarsier (Tarsiidae), branched off from the other haplorhines. This could explain why the prosimian tarsiers show characteristics which once caused them to be grouped with the strepsirrhines.[citation needed]

The remaining clade (Anthropoidea) is divided into two parvorders: Platyrrhini (the New World monkeys) and Catarrhini (the Old World monkeys and apes). The New World monkeys split from catarrhines about 40 mya, while the apes (Hominoidea) diverged from Old World monkeys (Cercopithecoidea) about 25 mya. The available fossil evidence indicates both the hominoid and cercopithecoid clades originated in Africa.[citation needed]

The following is the listing of the living Haplorrhine families, and their placement in the Order Primates:[1][4]

References[edit]

  1. ^ a b Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M, eds. Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 127–184. OCLC 62265494. ISBN 0-801-88221-4. 
  2. ^ Pollock, J. I.; Mullin, R. J. (1987). "Vitamin C biosynthesis in prosimians: Evidence for the anthropoid affinity of Tarsius". American Journal of Physical Anthropology 73 (1): 65–70. doi:10.1002/ajpa.1330730106. PMID 3113259. 
  3. ^ Ankel-Simons 2007, pp. 394–395.
  4. ^ Rylands AB and Mittermeier RA (2009). "The Diversity of the New World Primates (Platyrrhini)". In Garber PA, Estrada A, Bicca-Marques JC, Heymann EW, Strier KB. South American Primates: Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Springer. ISBN 978-0-387-78704-6. 

Literature cited[edit]