Langurs in Bangladesh Facing Extinction

[Strathmorezoo]

A recent study has found that Langurs in Bangladesh are facing extinction because of hybridization between the 500 Phayers Langur and the 600 Capped Langur in the Rainforests in the county's northeast. The hybridization is due to habitat loss and other human interference which could push them to extinction in future generations.

 

[Chlidonias]

From the Mongabay article: Langurs in Bangladesh face extinction as hybridization between species escalates

The study, published in the International Journal of Primatology, recently found that out of 98 langur groups observed, eight comprised both Phayre’s and capped langurs.
“We analyzed genetic samples of the species in the lab and confirmed one case of hybridization. This langur had a capped langur mother and a Phayre’s langur father. Another female with a hybrid appearance showed signs of motherhood, indicating that at least female hybrids are fertile and give birth to young,” Tanvir said.


Link to the paper itself: Mixed-Species Groups and Genetically Confirmed Hybridization Between Sympatric Phayre’s Langur (Trachypithecus phayrei) and Capped Langur (T. pileatus) in Northeast Bangladesh - International Journal of Primatology

From the abstract:

During our surveys, we encountered 98 groups of langurs of which 41 were Phayre’s langur groups, 49 capped langur groups, and eight mixed-species groups (8%). In three mixed-species groups, we detected three individuals of intermediate phenotype, among them one adult female whose nipples were elongated indicating that she had an infant, and thus was likely to be fertile. Genetic analyses confirmed the hybrid status (most likely F1) of one individual with intermediate phenotype. To our knowledge, there are no reports of mixed-species groups and hybridization from other parts of the range where the species occur sympatrically. Hence, it seems likely that such groups occur mainly in the northern part of their common range where natural habitats are deteriorating fast. Therefore, we suggest monitoring of the populations, to find out whether the frequency of mixed-species groups increases, and a large-scale population genetic study to investigate whether hybridization is a recent phenomenon or occurred historically in the zone of range overlap in Bangladesh.

 

[LaughingDove]

As they note in the paper, it's not really clear the extent to which this hybridisation is a new phenomenon or whether historic gene flow between these species has taken place. It's also not clear to what extent this observation of some hybridisation is a conservation concern in and of itself. An interesting story.

 

[Strathmorezoo]

Interestingly, Tanvir Ahmed noted "Langur populations are small and isolated, limiting gene flow. This hybridization in restricted populations heighten their extinction risks. Furthermore, our laws,primarily protect pure Langurs,leaving hybrids unprotected. If hybrids persist into future generations, we'll face tough decisions about their role in our ecosystems ".