Tarsius is a genus of primates in the Tarsiidae family, the only one surviving in the order of Tarsiiformes. This group used to have a wide spread, but all species that live today have a limited number and are found on islands in Sulawesi and the western Philippines.
Wallacea fossils and primates in other Tarsiiformes are found in the waste dumps of Asia, Europe and North America, while doubtful fossils are from Africa. Tarsius Darwin, who has survived until now, has a limited number of islands in Sulawesi, Kalimantan, Sumatra and Philippines.
Tarsier's fossil record is very long and continuous compared to any genus of primate which indicates that the arrangement of their teeth has not changed much, except its size, in the last 45 million.
Classification
The phylogenetic tarsiers that live on this day are much debated in the past century and are classified alternately in Strepsirrhini in the prosimia suborder or as a simia group in Haplorrhini infraordo. This genus should be classified into two groups, Sulawesi and West-Philippines.
Taxonomy at the species level is very complicated with morphology often used in a limited way compared to vocalization. Some forms of vocalisation may represent undescribed taxa which are taxonomically separate from Tarsius tarsiers such as Minahasa and Togean islands.
This may also be the case for a number of populations in Philippines that are isolated and have little known existence such as in Basilan, Leyte and Dinagat from the T. syrichta group. Further confusion arises in the validity of certain names where T. dianae is often used as a synonym for T. dentatus and T. spectrum is now considered a synonym for T. tarsier.
Infraorder: Tarsiiformes
Family: Tarsiidae
Genus: Tarsius
Anatomy and physiology
Tarsiers are small, very large eyes where each eyeball is about 16 mm in diameter and the whole size is the size of a brain. The head and body length is 10 to 15 cm but the hind legs are almost twice the length and the slender tail is 20 to 25 cm long.
The fingers extend with the third finger about the same length as the upper arm. The fingertips have nails, but the second and third fingers on the hind legs are claws to treat the body. The fur is very soft and velvety, grayish brown, light brown or light orange. Tarsiers do not have a tooth comb and their tooth arrangement is also unique 2.1.3.3 at the top and 1.1.3.3 at the bottom.
Vision
Tarsiers are nocturnal, but some individuals may move more during the day. They also don't have light reflecting areas in the eyes and also have foveas as something unusual in nocturnal animals.
The brain is different from other primates in the connection of the two eyes and the lateral geniculate nucleus which is the main area in the thalamus to receive visual information. A series of cellular layers that receive information from the ipsilateral and contralateral parts of the lateral geniculate nucleus will distinguish them from lemurs and monkeys.
Behavior
This genus includes insectivores and catches by ambush. They also prey on small vertebrates including birds, snakes, lizards and bats. They jump from one tree to another, even catching moving birds.
Pregnancy lasts six months to give birth to babies who have hairy, open eyes and a day later are able to climb trees. They become adults in one year. Adult tarsiers live in pairs within one hectare.
Tarsius never succeeded in forming breeding colonies in confinement and if they were locked up they would injure and even commit suicide because of stress. Environmental activists have developed large semi-wild cages equipped with light to attract nocturnal insects as their food.
Wallacea fossils and primates in other Tarsiiformes are found in the waste dumps of Asia, Europe and North America, while doubtful fossils are from Africa. Tarsius Darwin, who has survived until now, has a limited number of islands in Sulawesi, Kalimantan, Sumatra and Philippines.
Tarsier's fossil record is very long and continuous compared to any genus of primate which indicates that the arrangement of their teeth has not changed much, except its size, in the last 45 million.
Classification
The phylogenetic tarsiers that live on this day are much debated in the past century and are classified alternately in Strepsirrhini in the prosimia suborder or as a simia group in Haplorrhini infraordo. This genus should be classified into two groups, Sulawesi and West-Philippines.
Taxonomy at the species level is very complicated with morphology often used in a limited way compared to vocalization. Some forms of vocalisation may represent undescribed taxa which are taxonomically separate from Tarsius tarsiers such as Minahasa and Togean islands.
This may also be the case for a number of populations in Philippines that are isolated and have little known existence such as in Basilan, Leyte and Dinagat from the T. syrichta group. Further confusion arises in the validity of certain names where T. dianae is often used as a synonym for T. dentatus and T. spectrum is now considered a synonym for T. tarsier.
Infraorder: Tarsiiformes
Family: Tarsiidae
Genus: Tarsius
- T. syrichta (West-Filipina): Tarsius syrichta and Tarsius bancanus
- T. tarsier (Sulawesi): Tarsius tarsier, Tarsius dentatus, Tarsius lariang, Tarsius pelengensis, Tarsius sangirensis, Tarsius tumpara and Tarsius pumilus
Anatomy and physiology
Tarsiers are small, very large eyes where each eyeball is about 16 mm in diameter and the whole size is the size of a brain. The head and body length is 10 to 15 cm but the hind legs are almost twice the length and the slender tail is 20 to 25 cm long.
The fingers extend with the third finger about the same length as the upper arm. The fingertips have nails, but the second and third fingers on the hind legs are claws to treat the body. The fur is very soft and velvety, grayish brown, light brown or light orange. Tarsiers do not have a tooth comb and their tooth arrangement is also unique 2.1.3.3 at the top and 1.1.3.3 at the bottom.
Vision
Tarsiers are nocturnal, but some individuals may move more during the day. They also don't have light reflecting areas in the eyes and also have foveas as something unusual in nocturnal animals.
The brain is different from other primates in the connection of the two eyes and the lateral geniculate nucleus which is the main area in the thalamus to receive visual information. A series of cellular layers that receive information from the ipsilateral and contralateral parts of the lateral geniculate nucleus will distinguish them from lemurs and monkeys.
Behavior
This genus includes insectivores and catches by ambush. They also prey on small vertebrates including birds, snakes, lizards and bats. They jump from one tree to another, even catching moving birds.
Pregnancy lasts six months to give birth to babies who have hairy, open eyes and a day later are able to climb trees. They become adults in one year. Adult tarsiers live in pairs within one hectare.
Tarsius never succeeded in forming breeding colonies in confinement and if they were locked up they would injure and even commit suicide because of stress. Environmental activists have developed large semi-wild cages equipped with light to attract nocturnal insects as their food.
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