The biogeographical relations of the frogs and snakes of Sundaland

Abstract

Aim We seek to relate the present distributions of frogs and snakes of Sundaland and the known geological history of the region. Location From the Isthmus of Kra to Java and Sulawesi. Methods We relate the known ecological requirements of frogs and snakes to their geographical distributions and information on geological history. Results Microhabitat requirements for larvae of various groups of frogs are strong predictors of the breadth of their geographical distributions. At the species level, the frog faunas of the Malay Peninsula and Sumatra are the most similar. The Sulawesi frog fauna, mainly derived from Sundaland lineages, shows almost no similarity to the other frog faunas at the species level. The ecological zones occupied by snake species show association with the breadth of their geographical distributions There are only minor differences among similarity ratios for the Malay Peninsula–Sumatran, Malay Peninsula–Borneo, and the Borneo–Sumatra pairs. The Sulawesi snake fauna has distinctly lower similarity with the faunas of the other areas. The similarity ratios between faunas are larger for snakes than for frogs. This difference between the two groups reflects the difference between them in ability to cross salt water barriers, frogs being extremely vulnerable to saline water. Also snakes may establish founder populations more easily as a single gravid female or one carrying stored sperm may introduce a clutch into previously unoccupied territory. Conclusions A few species of frogs and snakes probably reached their present, almost ubiquitous distributions in Sundaland within the last few millenia or even more recently. Other widely distributed species may have been able to disperse among land masses within Sundaland until 10,000–17,000 yr BP; the frogs of this category are common in environments that almost certainly characterized the exposed area of the South China Sea. The distributions of other frogs common to the Malay Peninsula, Sumatra and Borneo probably antedate the Pleistocene, as their larval development requires hilly topography which was not generally available on the Pleistocene‐exposed bed of the South China Sea. Many of the endemic species of frogs and snakes probably owe their origins to events of the Miocene or earlier. Several genera of frogs and one genus of snakes have undergone extensive speciation and display considerable sympatry and elevational stratification of species, suggesting their present distributions are the result of events as old as the Eocene. We have cast these conclusions in the form of hypotheses that can be tested mainly by the use of molecular genetics, but in some cases, by additional field sampling.

Phylogenetic relationships of megophryid frogs of the genus Leptobrachium (Amphibia, Anura) as revealed by mtDNA gene sequences

“…This estimate does not contradict the idea that Mindanao became aerial about 25-30 MYBP in the late Oligocene (Brown and Alcala, 1994), but the route of faunal invasion remains unclear (Inger, 1999). Inger and Voris (2001) showed that disjunction of the Malay Peninsula from Borneo by the South China Sea (Fig. 1) occurred once about 5 MYBP in the early Pliocene.…”

“…Their ecology led Inger and Voris (2001) to associate them with Pleistocene dispersal between the Malay Peninsula and Borneo, while questioning their absence on Sumatra. The presence of L. hendricksoni on Sumatra is now confirmed, and its unique ecology does not seem to be related to Pleistocene dispersal.…”

“…The eastern boundary of Sundaland is Wallace's Line where the Indomalayan and Australasian faunas meet. Studies of some anuran lineages from Sundaland indicate that species distributions and phylogenies are strongly related to the geological history of this region (e.g., Emerson et al, 2000;Inger and Voris, 2001;Brown and Guttman, 2002;Matsui et al, 2010).…”

Microhabitat partitioning of closely related Sarawak (Malaysian Borneo)frog species previously assigned to the genus Hylarana (Amphibia: Anura)

“…On the other hand, regional processes (isolation, speciation) might contribute to geographic restrictions of several species, leading to variation in overlap values. Inger and Voris (2001) and Inger and Stuebing (2005) categorized the Sarawak frogs into 2 groups based on habitat utilization: i) town or village species (Hylarana erythraea (green paddy frog) and Amnirana nicobariensis (cricket frog), and ii) forests or forest edge species, which were further divided into inland hill species (category III: P. signata, P. picturata, A. luctuosa, C. raniceps) and species confined to coastal lowlands and swamp areas (Category II: P. baramica, P. glandulosa, and P. laterimaculata). However, there has been little study of microhabitat utilization by Sarawak frogs, except for studies on microhabitat utilization by Sarawak tadpoles by Inger (1985), and frogs of the Sarawak highlands (Zainudin et al, 2006).…”

Diferenciação geográfica de Ecpleopus gaudichaudii (Squamata, Gymnophthalmidae) baseada em caracteres morfológicos e moleculares, e considerações sobre a descrição osteológica

“…É sabido que existe um importante efeito de ilha em populações que ficam isoladas em alopatria. (Carvalho et al, 2007, Brown & Lomolino, 2000Inger & Voris, 2001, Quammen, 2008 O estudo osteológico abre a possibilidade de comparar a diferenciação osteológica dos diversos grupos dentro dos Gymnophthalmidae de maneira que auxiliem no entendimento do desenvolvimento e das relações filogenéticas desse grupo.…”