Indriidae
Order Primates
Suborder Prosimii/Strepsirrhini
Infraorder: Lemuriformes
First Indrids appear in Tertiary/Pliocene. Below data
interpreted from mitochondrial cyt-b gene sequencing in
2004.
3 Genera, 6 species
Genus Indri (indris)
Indri indri
Genus Avahi (woolly lemurs)*
Avahi laniger
Avahi occidentalis
Genus Propithecus (sifakas) – 8 subspecies
Propithecus diadema
P. d. diadema
P. d. candidus
P. d. edwardsi
P. d. perrieri
Propithecus verreauxi
P. v. verreauxi
P. v. coquereli
P. v. coronatus
P. v. deckeni
Propithecus tattersalli
*Genus Avahi was split into two species
based on chromosomal studies in 1988
All species endemic to Madagascar
Indris Montane rainforests from Bemarivo (Mahajanga)
and Anjanaharibe-Sud to Analamazaotra, Mangoro
River north to Sambava
Woolly LemursA. laniger - Ankarana to Ft. Dauphin
A. occidentalis - dry deciduous forest in/around
Ankarafantsika
Sifakas P. v. verreauxi - S/SW, west to Tsiribihina River
P. v. coquereli - along northwest coast
P. v. coronatus - just below coquereli
P. v. deckeni - west, and possibly to the north
P. d. perrieri* - northeastern tip
P. d. candidus* - just below perrieri
P. d. diadema* - small area between edwardsi and candidus
P. d. edwardsi* - south
P. Tattersalli - NE in forest fragments in/around
Antanimarazoko (only about 88000 ha,
half of which is forest)
Morphology & Physiology
• Dental formula: 2/1, 1/1, 2/2, 3/3 = 30
• Toothcomb consists of lower incisors and canines (4 teeth)—most Strepsirhines use 6 teeth)
- toothcomb used in grooming (social behavior, reciprocity)
• Indrids have a shortened snout due to a reduced dental formula
• Enlarged upper incisors
• Elongated upper canine,
• First lower premolar is canine-like
P. diadema
P. Diadema - upper jaw
Morphology & Physiology
• Globular brain case
• Bullae overgrow and incorporate the tympanic ring
• The two dentaries are joined by a long and oblique symphysis, and each is characterized by an enlarged
angular process
P. diadema
P. diadema
Morphology & Physiology
• Hindlimbs 1/3 longer than forelimbs
• Hands long, strong and slender
• Nails on all digits of forelimbs
• Hind feet large, but narrow (why do not walk well)
• Opposable hallux (big toe) on hind feet
• Hind toes 2-5 are webbed (may assist in leaping)
A. laniger
A. occidentalis
• Long tail
I. indri
P. Diadema
P. Tattersalli
P. verreauxi
Morphology & Physiology
• Fold of skin from chest to arms (vestigial gliding membrane?)
Locomotion: vertical clingers and leapers that spend
majority of time in trees (some up to 33 feet)
Behavior
• Scent marking
• Howling, kissing sounds (affection), barks (danger)
• Facial expressions
• All species diurnal less Avahi sp. which are nocturnal
• Indri and Avahi live in groups of 2-5
• Propithecus live in groups of up to 10
• Avahi monogamous
Diet
• Vegetarians/Folivorous: leaves, fruits, bark, flowers
• Stomachs are simple but large to digest plant material
• Intestinal tracts are unusually long (elongated caecum)
•Well developed salivary glands (adapted to leaves)
Sifaka – groud predator
Sifaka – lost
Sifaka – roar
Leaping Indri
Leaping Sifaka
Dancing Sifaka
Conservation
• All rate either vulnerable, endangered, or critically endangered because of humans
• Isolated to island
• Habitat destruction for agriculture, timber, charcoal
• Some hunted as food by man and raptors
•P. tattersalli does not reside in protected areas
• P. v. coronatus down to 100-1000 individuals
• Indri likely extinct within 100 years without better regulations
Reserves include: Analamera Special Reserve,
Ankarafantsika Nature Reserve, Manongarivo Special
Reserve, Tsingy de Bemaraha National Park, Ankarana Special
Reserve
A. occidentalis