page_title: Strepsirrhini
section_title: History of classification
hierarchical_section_title: Strepsirrhini / History of classification
caption_attribution_description: English: Photograph of lithographic portrait of Étienne Geoffroy Saint-Hilaire (aged about 70).
context_page_description: Strepsirrhini or Strepsirhini is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos and pottos from Africa, and the lorises from India and southeast Asia. Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct adapiform primates that thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.
  Strepsirrhines are defined by their "wet" rhinarium - hence the colloquial but inaccurate term "wet-nosed" - similar to the rhineria of dogs and cats. They also have a smaller brain than comparably sized simians, large olfactory lobes for smell, a vomeronasal organ to detect pheromones, and a bicornuate uterus with an epitheliochorial placenta. Their eyes contain a reflective layer to improve their night vision, and their eye sockets include a ring of bone around the eye, but they lack a wall of thin bone behind it.
context_section_description: The taxonomy of strepsirrhines is controversial and has a complicated history. Confused taxonomic terminology and oversimplified anatomical comparisons have created misconceptions about primate and strepsirrhine phylogeny, illustrated by the media attention surrounding the single "Ida" fossil in 2009.
  Strepsirrhine primates were first grouped under the genus Lemur by Swedish taxonomist Carl Linnaeus in the 10th edition of Systema Naturae published in 1758. At the time, only three species were recognized, one of which (the colugo) is no longer recognized as a primate. In 1785, Dutch naturalist Pieter Boddaert divided the genus Lemur into two genera: Prosimia for the lemurs, colugos, and tarsiers and Tardigradus for the lorises. Ten years later, É. Geoffroy and Georges Cuvier grouped the tarsiers and galagos due to similarities in their hindlimb morphology, a view supported by German zoologist Johann Karl Wilhelm Illiger, who placed them in the family Macrotarsi while placing the lemurs and tarsiers in the family Prosimia (Prosimii) in 1811. The use of the tarsier-galago classification continued for many years until 1898, when Dutch zoologist Ambrosius Hubrecht demonstrated two different types of placentation (formation of a placenta) in the two groups.
  English comparative anatomist William Henry Flower created the suborder Lemuroidea in 1883 to distinguish these primates from the simians, which were grouped under English biologist St. George Jackson Mivart's suborder Anthropoidea (=Simiiformes). According to Flower, the suborder Lemuroidea contained the families Lemuridae (lemurs, lorises, and galagos), Chiromyidae (aye-aye), and Tarsiidae (tarsiers). Lemuroidea was later replaced by Illiger's suborder Prosimii. Many years earlier, in 1812, É. Geoffroy first named the suborder Strepsirrhini, in which he included the tarsiers. This taxonomy went unnoticed until 1918, when Pocock compared the structure of the nose and reinstated the use of the suborder Strepsirrhini, while also moving the tarsiers and the simians into a new suborder, Haplorhini. It was not until 1953, when British anatomist William Charles Osman Hill wrote an entire volume on strepsirrhine anatomy, that Pocock's taxonomic suggestion became noticed and more widely used. Since then, primate taxonomy has shifted between Strepsirrhini-Haplorhini and Prosimii-Anthropoidea multiple times.
  Most of the academic literature provides a basic framework for primate taxonomy, usually including several potential taxonomic schemes. Although most experts agree upon phylogeny, many disagree about nearly every level of primate classification.
caption: The suborder Strepsirrhini was proposed by É. Geoffroy in 1812.
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