Strepsirrhini

Strepsirrhini or Strepsirhines are an infraorder of primates that includes the lemurs of Madagascar, the lorises of Asia and Africa, and the galagos, or bushbabies, of Africa. Strepsirrhines are distinguished from other primates by their wet nose or rhinarium, which is thought to contribute to their enhanced sense of smell. They are also characterized by a generally smaller size compared to their primate cousins, the Haplorhini (tarsiers, monkeys, and apes, including humans).

Characteristics

Strepsirrhines possess a unique dental structure known as the "toothcomb," which is used for grooming. This feature, along with their large, forward-facing eyes, contributes to their classification. Their brain-to-body size ratio is smaller than that of the Haplorhini, and they have a more developed sense of smell, which is facilitated by the moist, naked surface around their nostrils. The majority of strepsirrhines are nocturnal, although some species, like the ring-tailed lemur, are diurnal.

Evolution and Distribution

The Strepsirrhini infraorder is believed to have diverged from the ancestral primate lineage during the Paleocene, about 63 million years ago. Their distribution is primarily in the southern hemisphere, with lemurs found exclusively in Madagascar, lorises in Southeast Asia and India, and galagos in sub-Saharan Africa. The isolation of Madagascar has allowed lemurs to evolve in a wide variety of forms, leading to the high biodiversity seen today. However, this isolation has also made them highly susceptible to extinction pressures.

Conservation Status

Many strepsirrhine species are threatened by habitat destruction, hunting, and the illegal pet trade. Conservation efforts are critical for their survival, with numerous species listed as endangered or critically endangered by the International Union for Conservation of Nature (IUCN). The unique biodiversity of Madagascar makes the conservation of its endemic species, including many lemurs, a priority for global biodiversity.

Research and Importance

Strepsirrhines are important for scientific research due to their position in the primate evolutionary tree. They offer insights into the evolutionary history and adaptations of primates, including sensory modalities, social structures, and reproductive strategies. Their study contributes to our understanding of primate evolution, ecology, and conservation.

See Also

• Primate
• Lemur
• Loris
• Galago
• Madagascar
• Conservation status
• Evolution of primates