Zoogeographic Significance of Caraballo Mountain Range, Luzon Island, Philippines With Focus on the Biogeography of Luzon’s Herpetofauna

Paul Henric P. Gojo Cruz1* and Leticia E. Afuang2

1Faculty, Department of Biological Sciences, College of Arts and Sciences,
Central Luzon State University, Science City of Muñoz, Nueva Ecija
2Faculty, Animal Biology Division, Institute of Biological Sciences,
College of Arts and Sciences, University of the Philippines Los Baños, Laguna


*Corresponding authors: This email address is being protected from spambots. You need JavaScript enabled to view it.




Our recent survey in the Caraballo Mountain Range contributed knowledge about the distribution of herpetofauna of Luzon Island, and allowed comparison of species composition among Luzon’s biogeographic regions. Data collection was done using intensive herpetofaunal survey in the sampling area in Pantabangan-Carranglan Watershed in Carranglan, Nueva Ecija in the Caraballo Mountains. Comparison with Luzon’s mountain ranges was done using presence-based Jaccard similarity index. Extensive literature survey of available distribution data for Luzons’ herpetofauna revealed 153 native and non-native species (45 species of frogs, 65 lizards, 40 snakes, and 3 turtles) representing about 44% of the Philippine herpetofauna. Twenty-five (25) species of frogs and 71 species of reptiles are considered as restricted range, found only in one to three biogeographic regions. Jaccard similarity index showed that the herpetofauna of the Caraballo is most similar to that of the northern Sierra Madre (J= 0.50) and Cordillera Mountain Ranges (J=0.45). The available data showed that the Caraballo has a variable role with regards to Luzon’s herpetofaunal biogeography. The Caraballo possess frogs and snakes that are also found in the Sierra Madre and Cordillera, implying that the mountain range is a site of amalgamation for these faunas. On the other hand, it serves as a filter zone and dispersal barrier for burrowing and diminutive skinks and frugivorous varanids, based on the observed distribution of some members of the genus Brachymeles, Parvoscincus, and Varanus. This result confirms the importance of the Caraballo Range as an important biogeographic link between Sierra Madre and Cordilleras. This maybe attributed to the physical connection that provides shared topography and bioclimatic conditions among the biogeographic regions.



Philippine amphibians and reptiles exhibit high diversity and endemicity. The latest studies listed 112 species of amphibians and 357 species of reptiles in the country, with about 84% endemicity of recorded amphibians and 66% of recorded reptiles (Diesmos et al. 2002; Diesmos et al. 2015). Several studies (Auffenberg 1988; Brown et al. 1996; Diesmos et al. 2005; Siler et al. 2011; Welton et al. 2010, 2012; Brown et al. 2013) on amphibians and reptiles have shown or explained possible dispersal routes, zoogeographical ranges and relationships, and land-bridge connections. Diesmos and co-authors (2002) recognized nine herpetofaunal regions or Pleistocene aggregate island complexes (PAIC) as follows: Batanes PAIC, Babuyanes . . . . . read more



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