Overview of the visual system of <i>tarsius</i>

Collins, Christine E.; Hendrickson, Anita E.; Kaas, Jon H.

doi:10.1002/ar.a.20263

Cited by 63 publications

(59 citation statements)

References 48 publications

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“…However, tarsiers exhibit highly unusual features for nocturnally adapted species (76). Like anthropoids, but unlike all other mammals, tarsiers possess a retinal fovea (a pit in the central retina) and a macula lutea (produced by a high concentration of carotenoid pigments around the fovea).…”

Section: Adaptations In Anthropoideamentioning

confidence: 99%

New perspectives on anthropoid origins

Williams

Kay

Kirk

2010

Proc. Natl. Acad. Sci. U.S.A.

117

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Adaptive shifts associated with human origins are brought to light as we examine the human fossil record and study our own genome and that of our closest ape relatives. However, the more ancient roots of many human characteristics are revealed through the study of a broader array of living anthropoids and the increasingly dense fossil record of the earliest anthropoid radiations. Genomic data and fossils of early primates in Asia and Africa clarify relationships among the major clades of primates. Progress in comparative anatomy, genomics, and molecular biology point to key changes in sensory ecology and brain organization that ultimately set the stage for the emergence of the human lineage.primate | Haplorhini | Strepsirrhini | human evolution | phylogeny

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Section: Adaptations In Anthropoideamentioning

confidence: 99%

New perspectives on anthropoid origins

Williams

Kay

Kirk

2010

Proc. Natl. Acad. Sci. U.S.A.

117

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“…Tarsiers have become so specialized that they eat no vegetable food. Little is known about how their brains are organized, except that primary visual cortex is huge relative to other brain areas, and much of caudal neocortex is visual [5]. Primary auditory, somatosensory and motor systems also appear to be present.…”

Section: Early Anthropoid Primatesmentioning

confidence: 99%

The evolution of the complex sensory and motor systems of the human brain

Kaas

2008

Brain Research Bulletin

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141

120

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Inferences about how the complex sensory and motor systems of the human brain evolved are based on the results of comparative studies of brain organization across a range of mammalian species, and evidence from the endocasts of fossil skulls of key extinct species. The endocasts of the skulls of early mammals indicate that they had small brains with little neocortex. Evidence from comparative studies of cortical organization from small-brained mammals of the six major branches of mammalian evolution supports the conclusion that the small neocortex of early mammals was divided into roughly 20-25 cortical areas, including primary and secondary sensory fields. In early primates, vision was the dominant sense, and cortical areas associated with vision in temporal and occipital cortex underwent a significant expansion. Comparative studies indicate that early primates had 10 or more visual areas, and somatosensory areas with expanded representations of the forepaw. Posterior parietal cortex was also expanded, with a caudal half dominated by visual inputs, and a rostral half dominated by somatosensory inputs with outputs to an array of seven or more motor and visuomotor areas of the frontal lobe. Somatosensory areas and posterior parietal cortex became further differentiated in early anthropoid primates. As larger brains evolved in early apes and in our hominin ancestors, the number of cortical areas increased to reach an estimated 200 or so in present day humans, and hemispheric specializations emerged. The large human brain grew primarily by increasing neuron number rather than increasing average neuron size.

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“…Yet, the strength of this evidence is weakened in part by living tarsiers, which, though nocturnal, share many of these same traits. For example, tarsiers possess a fovea, a macula lutea and a central retina with relatively high densities of cones ( [7][8][9][10]; figure 1a). These features have long provoked an important question: are these character traits convergent in tarsiers and anthropoids, and, therefore, unrelated to diurnality, or are they synapomorphic retentions from a diurnal stem haplorhine?…”

Section: Introductionmentioning

confidence: 99%

Inferred L/M cone opsin polymorphism of ancestral tarsiers sheds dim light on the origin of anthropoid primates

et al. 2013

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Tarsiers are small nocturnal primates with a long history of fuelling debate on the origin and evolution of anthropoid primates. Recently, the discovery of M and L opsin genes in two sister species, Tarsius bancanus (Bornean tarsier) and Tarsius syrichta (Philippine tarsier), respectively, was interpreted as evidence of an ancestral long-to-middle (L/M) opsin polymorphism, which, in turn, suggested a diurnal or cathemeral (arrhythmic) activity pattern. This view is compatible with the hypothesis that stem tarsiers were diurnal; however, a reversion to nocturnality during the Middle Eocene, as evidenced by hyperenlarged orbits, predates the divergence of T. bancanus and T. syrichta in the Late Miocene. Taken together, these findings suggest that some nocturnal tarsiers possessed high-acuity trichromatic vision, a concept that challenges prevailing views on the adaptive origins of the anthropoid visual system. It is, therefore, important to explore the plausibility and antiquity of trichromatic vision in the genus Tarsius. Here, we show that Sulawesi tarsiers (Tarsius tarsier), a phylogenetic out-group of Philippine and Bornean tarsiers, have an L opsin gene that is more similar to the L opsin gene of T. syrichta than to the M opsin gene of T. bancanus in non-synonymous nucleotide sequence. This result suggests that an L/M opsin polymorphism is the ancestral character state of crown tarsiers and raises the possibility that many hallmarks of the anthropoid visual system evolved under dim (mesopic) light conditions. This interpretation challenges the persistent nocturnal-diurnal dichotomy that has long informed debate on the origin of anthropoid primates.

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Overview of the visual system of tarsius

Cited by 63 publications

References 48 publications

New perspectives on anthropoid origins

New perspectives on anthropoid origins

The evolution of the complex sensory and motor systems of the human brain

Inferred L/M cone opsin polymorphism of ancestral tarsiers sheds dim light on the origin of anthropoid primates

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