Guest Lecture - Mr. Brian Stafford, Department of Vertebrate Zoology, National Museum of Natural History

"Flying lemurs , they do not fly and they are not lemurs, so what do they do, and what are they?"

1. Introduction
   1. "Flying lemur" is a misnomer which began when Carolus Linnaeus put these animals in the same genus as lemurs; correct name is colugo
   2. Order Dermoptera, family Galeopithecidae
   3. Two species, Cynocephalus volans and Galeopterus variegatus
   4. Distribution: Cynocephalus is in the Philippines
      Galeopterus is in the Southeast Asian mainland, Sumatra, Java, and all intervening islands (the Sunda continental shelf region)

2. Morphology
   1. C. v. - 1.0 - 1.5 kg smaller yet more robust than G. v.
   2. G. v. - 1.25 - 1.75 kg larger yet more gracile (delicate) form
   3. Sexual dimorphism - in v. , females are larger than males; females are grayish and lighter, while males are browner and darker
   4. Confusing color patterns - colors vary geographically
   5. Dwarfing - colugos on the smaller islands tend to "dwarf", or become smaller

3. Ecology and Behavior
   1. Nocturnal or crepuscular
   2. Hindgut fermenting folivores that specialize on young leaves, with rapid rates of digestive passage
   3. Home range in Philippines is approximately 10 ha
   4. Nightly travel of up to 1.7 km (ie, they travel alot)
   5. May be solitary and territorial

4. Digestive Physiology
   1. Hindgut fermenters with an enlarged cecum and high rates of digestive passage for a folivore. Compare to other folivores:

      37 hours of digestive passage forC. v.
      632 hours of digestive passage for Bradypus variegatus (sloth)
      213 hours of digestive passage for Phascolarctos cinereus (koala)

   2. Higher rate of digestive passage may be due to the consumption of young leaves, which are easier to digest; however, young leaves are rarer and more patchily distributed than mature leaves
   3. Gliding is a low energy method of travelling long distances. Compare:

      1381 m/night for colugo
      less than 100 m/day for sloth
      less than 100 m/day for koala
      However: 1312 m/day for Nasalus larvatus (proboscis monkey)

   4. D. Colugo activity budget

   Hanging	54%
   Feeding	14%
   Moving	11%
   Grooming	9%
   Clinging	8%
   Other	3%

5. Craniodental Functional Morphology
   1. C. v. and G. v. have various morphological differences in the craniodental region, presumably due to differences in feeding ecology

   Cynocephalus volans	Galeopterus variegatus
   (more robust)	(more gracile)
   larger teeth	smaller teeth
   more developed ectocranial structures	less developed ectocranial structures
   temporal ridges meet	don't meet (relatively larger brain)
   auditory meatus pinched, narrow	open, round
   greater distance from teeth to origin of masseter muscles	smaller distance ""
   mandible deeper	mandible shallower
   larger coronoid process	smaller coronoid process
   large triangular shearing surfaces	smaller shearing surfaces
   canine-like incisors	pectinate (comb-like) incisors

   2. Both species have lower molars which form a tooth-comb, for use in grooming - in captivity colugos may die when they get moldy and mildew inside their flying membranes

6. Comparisons to other gliding mammals
   1. Other gliding mammals include:
      1. Other placental mammals

         Flying squirrels (Order Rodentia, family Pteromyinae)
         Scaly-tailed flying squirrels (Order Rodentia, family Anomaluridae)

      2. Gliding marsupials

         Family Pseudocheiridae - Ring-tailed possums
         Family Petaurinae - Striped possums, Leadbetter's possums, Gliding possums
         Family Acrobatidae - Feather-tailed possums

      3. Fossil species
   2. Gliding membrane - in colugos, the membrane completely encloses the hands, feet, and tail- only mammal in which the membrane completely encloses the body
   3. Aerodynamics - lift and drag must be balanced - an animal or object can fly further by increasing lift or decreasing drag For various aerodynamic measures, colugos are very close to other gliding mammals, not to bats

7. Taxonomy - where do the colugos belong?
   1. Three hypotheses
      1. Volitantia Illiger, 1811 - hypothesis that bats and flying lemurs are sister taxa (most closely related to each other) Some complex characters of the wrist and elbow do support this hypothesis; however, these could be convergent adaptations for airborne travel. In addition, bats and colugos are the only mammals in which the clavicle articulates with the 1st rib. However, this could also be a convergent adaptation for a wider wing span.
      2. Primatomorpha Beard, 1989 - hypothesis that primates and colugos are most closely related to each other This hypothesis is based on fossils found in Wyoming, which have been reconstructed to display long, straight fingers and an elongated middle bone within the finger. Since the only other fossil mammals from that deposit are primates, colugos were hypothesized to be primates. If this is the case, it has paleobiological implications. When the fossil primates known as plesiadapiformes declined due to competition from rodents, the only group to survive was the paromomyiformes. If these were gliders, the reduced competition could explain their survival. In addition, colugos spend a great deal of time clinging to vertical trunks, as did early primates.
      3. Mammalia Incertae sedis - says that we know they're mammals, but we don't know who they're most closely related to