Sunday, May 23, 2010

Photo of the day: Polymorphism in Ebony langurs

Silver leaf langurs (Trachypithecus cristatus cristatus) Ebony langurs (Trachypithecus auratus auratus) are endemic to the islands of Java but the red morph (like the one above) occurs only in the eastern part. Photo taken at Bronx Zoo's Jungle World.

Correction: Thanks to reader Vincent Nijman for pointing out that it is an Ebony langur, not Silver leaf langur. That oughta teach me to write notes, not use mental notes.


Anonymous said...

Unless I am terribly wrong this is not Trachypithecus cristatus but T auratus from Java (the fringe gives it away, amongst others). Never been to the Bronx Zoo but it seems [ISIS database] that they have both species.

The erythristic morph of cristatus is confined to a small area in eastern Sabah [Malaysian Borneo] and very few, if any, are in zoos. The erythristic morph of T auratus is found in a larger area in eastern part of the province of East Java [Indonesia]. People seem to like the red one, hence it seems to be over-represented in trade, zoos and in zoological museums.

Nice picture though

Vincent Nijman

Raymond Ho, FCD said...

You are absolutely correct, Vincent. Sorry for the mixed up!

I think the red morph is interesting because it demonstrates how polymorphism plays into evolution and genetic frequency.