Primate Bio - Tarsiers

Tielhardina

-classic tarsier ancestor; early eocene omomyid -europe, asia, north america -larger eyes sockets

Necrolemur

-eocene omomyid -europe

why is a tarsier unique?

-fused tibia & fibula -longest foot bones of any primate -enlarged, pointed anterior teeth (incisors), no tooth comb -unique jaw joint = gutter-like fore and aft movement -resemble eocene omomyids w/ all these features -largest babies relative to body size -diets almost entirely of animal prey

Tarsier sociality

-group size is variable -have 2 adult females (multiple breeding females) -facultative polygyny -t. bancanus & t. syrichta have no group living, but overlapping home ranges

tarsier reproduction

-litter size is strictly one -bicorneate uterus capable of producing 2 offspring but do not -2-3 pairs of mammary glands -might have been producing more offspring in past than do today -seasonal breeders in the wild, but not captivity -mothers stay pretty close to infants when they are parked

What do molecules say?

-mtDNA links tarsiers w/ strepsirrhines -nuclear genes are inconsistent, some link w/ streps, some w/ anthropoids -split is probably too ancient for molecules to resolve it now -3 way divergence at around 60 mya

Rooneyia

-omomyid from North America

Features of a Tarsier

-oversized eyes -long tarsal bones/elevated ankle -low IMI (short arms, VCL) -easy to catch (poor eyesight) -very small -no tooth comb, sharp incisors -eye orbit not entirely closed from behind -dry nose w/ whole upper lip -hemochorial placenta -no tapetum lucid -grooming claw

partially enclosed orbits

-tarsiers descended from omomyids (which had open orbits) -closure caused by flanges of sphenoid and maxilla bones -convergent w/ that of anthropoids -provide support for protruding eyeball

Why have big eyes?

-tarsiers lack tapetum lucidum -enlarging eye = more light can come in, better visibility -tarsiers have a slight fovea, strepshirrines do not

Tarsier hearing & communication

-upper auditory limit of 91khz -had one distinct call that was entirely ultrasound -exceptional hearing of tarsiers contributes to foraging efficiency through acoustic eavesdropping -tarsiers might attend to ultrasonic signals b/w prey species signifying presence and location of predators

Tarsier dental formula

-very reduced: 2.1.3.3/1.1.3.3

3 groups of tarsiers

Philippine, Western, and Eastern Tarsiers -ear size increases and eye size decreases from western to philippine to eastern