Sunday, May 31, 2015

[Herpetology • 2015] Undiagnosed Cryptic Diversity in Small, Microendemic Frogs (Leptolalax) from the Central Highlands of Vietnam

Fig 3. Images in life of frogs in the Leptolalax applebyi group.
(A) Leptolalax applebyi (= molecular lineage 1; Kon Tum Province, Vietnam), (B) Leptolalax melicus (= molecular lineage 2; Ratanikiri Province, Cambodia), (C) Leptolalax sp. (= molecular lineage 3; Gia Lai Province, Vietnam), (D) L. bidoupensis (= molecular lineage 4; Lam Dong Province, Vietnam), (E) Leptolalax sp. (= molecular lineage 5; Lam Dong Province, Vietnam), (F) Leptolalax sp. (= molecular lineage 6; Binh Thuan Province; photo: Pedro Peloso), (G) Leptolalax sp. (= molecular lineage 7; Dak Lak Province, Vietnam), (H) Leptolalax sp. (= molecular lineage 8; Ninh Thuan Province, Vietnam), (I) Leptolalax sp. (= molecular lineage 9; Dak Nong Province, Vietnam).


A major obstacle in prioritizing species or habitats for conservation is the degree of unrecognized diversity hidden within complexes of morphologically similar, “cryptic” species. Given that amphibians are one of the most threatened groups of organisms on the planet, our inability to diagnose their true diversity is likely to have significant conservation consequences. This is particularly true in areas undergoing rapid deforestation, such as Southeast Asia. The Southeast Asian genus Leptolalax is a group of small-bodied, morphologically conserved frogs that inhabit the forest-floor. We examined a particularly small-bodied and morphologically conserved subset, the Leptolalax applebyi group, using a combination of molecular, morphometric, and acoustic data to identify previously unknown diversity within. In order to predict the geographic distribution of the group, estimate the effects of habitat loss and assess the degree of habitat protection, we used our locality data to perform ecological niche modelling using MaxEnt. Molecular (mtDNA and nuDNA), acoustic and subtle morphometric differences revealed a significant underestimation of diversity in the L. applebyi group; at least two-thirds of the diversity may be unrecognised. Patterns of diversification and microendemism in the group appear driven by limited dispersal, likely due to their small body size, with several lineages restricted to watershed basins. The L. applebyi group is predicted to have historically occurred over a large area of the Central Highlands of Vietnam, a considerable portion of which has already been deforested. Less than a quarter of the remaining forest predicted to be suitable for the group falls within current protected areas. The predicted distribution of the L. applebyi group extends into unsurveyed watershed basins, each potentially containing unsampled diversity, some of which may have already been lost due to deforestation. Current estimates of amphibian diversity based on morphology alone are misleading, and accurate alpha taxonomy is essential to accurately prioritize conservation efforts.

Fig 1. Map showing the localities where specimens in the Leptolalax applebyi group were collected.
Colours of localities assigned based on the nine molecular lineages. Paler areas are higher elevation. Dark grey lines show country boundaries, pale grey lines show watershed boundaries and blue lines show rivers.

Jodi J. L. Rowley, Dao T. A. Tran, Greta J. Frankham, Anthony H. Dekker, Duong T. T. Le, Truong Q. Nguyen, Vinh Q. Dau and Huy D. Hoang. 2015. Undiagnosed Cryptic Diversity in Small, Microendemic Frogs (Leptolalax) from the Central Highlands of Vietnam.
DOI:  10.1371/journal.pone.0128382