Subsequent to the Miocene (approximately 35 Mya), Borneo has served as an insular refuge and a source of colonization for a broad range of species emigrating to others parts of Sundaland. A phylogeny-based historical biogeographical hypothesis for the Stream Toad genus Ansonia supports multiple instances of an out-of-Borneo scenario. An ancestral range estimation indicates that in situ speciation of Ansonia on the island of Borneo during the Late Miocene and Pliocene (approximately 2-13 Mya) eventually resulted in an invasion of the Philippines, Sumatra, and two independent invasions of the Thai-Malay Peninsula. When collecting material for the biogeographical analysis, a new species of Ansonia, Ansonia khaochangensis sp. nov. was discovered in a limestone cave from the Khao Chang karst tower in Phangnga Province, in southern Thailand. Ansonia khaochangensis sp. nov. can be differentiated from all other species of Ansonia by having a unique combination of morphological and colour pattern characteristics. Phylogenetic evidence based on the mitochondrial genes 12S and 16S indicates that it is nested within a clade of other species distributed north of the Isthmus of Kra. The cave lifestyle of this new species is a unique and a significant departure from lotic environments common to most other species of Ansonia. The reproductive biology of this species is unknown.
Bibliographical noteFunding Information:
Funding for LLG came from grants from the College of Arts and Sciences at La Sierra University and from a National Geographic Society Explorers Grant (9277-15). Partial funding for PLWJ and CA was from a NSF dimensions grant EF-1241885 issued to Jack W. Sites Jr (JWSJ). Additional funding for PLWJ was from a Doctoral Dissertation Improvement Grant (DDIG 1501198) issued to PLWJ and JWSJ. We wish to thank two anonymous reviewers and Masafumi Matsui for many helpful comments
- Karst ecosystem