TROPICS Vol. 10 (1): 5L-62 Issued May 30, 2000 The Curent Geographic Faunal Pattern of Reptiles and Amphibians of the Ryukyu Archipelago and Adjacent Regions Hidetoshi Ou Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan ABSTRACT The Ryukyu Archipelago accomrhodates 52 native species/subspecies (26 genera belonging to ten families) of tenestrial reptiles and 22native species/subspecies (ten genera belonging to six families) of amphibians. This paper reviews the geographic similarity and diversity pattemJoflhe current herpetofauna of the Ryukyus and adjacent regions, and discusses factors influencing the formation of it in this archipelago. Cluster analyses of similarity indices for both reptiles and amphibians indicate that the Ryukyu herpetofauna is strongly influenced by geohistory ofthis archipelago involving long isolation especially in its north-cenhal part (i.e., southem Tokara, Amami, anA Oiinawa Groupsf Correlation analyses suggest that the faunal diversity on each island is significantly influenced by iis habitat diversity as reflected by the island area (for reptiles) or height (amphibians). Key words: herpetofauna / isolation / paleogeography / habitat diversity The Ryukyu Archipelago is an assemblage of old continental islands located in the humid subtropical area of the western Pacific (Takara, 1962l' Kizaki, 1985: Fig. 1). This archipelago accommodates a diverse biota including various reptiles and amphibians (e.g., Ikehara & Kato, 1997). Several previous authors have analysed the Ryukyu herpetofauna (e.g., Inger, L947; Koba, 1962; Kuramoto, 1979) and argued the predominaace of Oriental elements (i.e., taxa having closest relatives in southeastern China and Southeast Asia) over Palearctic elements (i.e., those most closely related to taxa in the main-islands of Japan and eastern China). Since then, a number of taxonomic changes have been made for the Ryukyu herpetofauna as a result of discoveries of new taxa, as well as of philosophical and methodological improvements of biological systematics [see Ota (2000) for example]. In this paper, I briefly review the geographic similarity and diversity patterns of the current herpetofauna of the Ryukyu Archipelago and adjacent regions by incorporating information recently added to our knowledge. I then discuss factors influencing the formation of that herpetofauna in this region. 52 H. OtA Tokara GaP*- -}- rokara Group C \.o Amami GrouP ' Keramauapr -\ -nkinawa Group / t Senkaku \ ' I Group -; \ MiYako GrouP ' A \. "N YaeYamaGrouP tai{ant \ Fig. 1. Map of East Asia showing .b \ /. the location of the RYukYu \a Archipelago. HERPETOEATJNAL DIVERSITY OF TIIE RYUKYU ARCHIPEI,AGO located The native herpetofauna of the Ryukyus (here defined as an assemblage of continental islands (26 between the Tokara Tectonic Strait and the Yonaguni Strait) consists of 52 species/subspecies belongrng genera belonging to ten families) of terrestrial reptiles and 22 species/subspecies (10 genera to 68'4Vo and to six families) of amphibians (Tables 1 and 2). These numbers, respectively, correspond amphibians so far 36.7Vo ofthe total numbers of native tenestrial species/subspecies of reptiles and the fact known from the whole Japan. These values are surprisingly high, especially when considering that in area the Ryukyu Archipelago constitutes only about Llo of the whole Japan. GEOGRAPHIC PAITERN OF EAUNAL SIMII,ARITY pattern of Biogeographical subdivision of the Ryukyu Archipelago. Based on the geographic here could be endemism in the terrestrial reptiles and amphibians, the Ryukyu Archipelago as defined the divided into six areas (Hikida & Ota, 1997; Ota, 1997, 19982 note that these works incorporated Daito Group, an assemblage of purely oceanic islands southeast of the Ryukyu Arc, into the Ryukyu Archipelago): Area I, a few small islands of the Tokara Group south to the Tokara Strait; Area II' northern half of the Amami Group; Area III, the Okinawa Group, including a few islands "politically" Geographic faunal pattern of reptiles and amphibians of the Ryukyus 53 Table 1. Terrestrial reptiles of Japan. Their occurrences in Taiwan and Fujian (southeastern continental China) are also indicated. Data are taken from Hikida & Ota (L997) and Ota (1998), with slight modifications as indicated in foot-notes. Asterisks (*) denote populations of artificial origins. Abbreviations are: MJ, the Main-islands of Japan and adjacent islands (including the lzu Group and the Tsushima Islands); TK, Tokara Group south of the Tokara Tectonic Strait; AM, Amami Group; OK, Okinawa Group; MY, Miyako Group; yy, yaeyama Group; SE, Senkaku Group; DA, Daito Group; oG, ogasawara and Iou Groups; TW, Taiwan; FJ, Fujian (the province of continental China nearest to Taiwan). Ryukyu Archipelago MJ TK AM OK MY YY SE DA OG TW FJ TESTUDINES Bataguridae Chinemys reevesii +l +* C i s to c le mmy s fl av om a r ginata Ci. f. evelynae Geoemyda japonica Mauremys japonica +l M. mutica M. m. mutica +* M. m. kami +* +* +* Emydidae Trachemys scripta 2" s. elegans +*l +* +* +* Trionychidae Pelodiscus sinensis +1 +* +* +* +* LACERTILIA Agamidae Japalura polygonata J. p. polygonata J. p. ishigakiensis Eublepharidae Goniur osaurus kur oiwae G. k. kuroiwae + G. k. orientalis + G. k. splendens G. k. toyamai + G. k. yamashinge + Gekkonidae Gehyra mutilata Gekko japonicus +1 Gk. hokouensis +1 + + Gk. tawaensis +l Gk. yakuensis +l H emidacty lus bow rin gii + + + Hd. frenatus +* +* +* +* +* +* +* H emiphy llodacty lus typus +* +* +{' Lepidodacty lus lugubris +* +{' +* + +{' Perochirus ateles + Iguanidae Anolis carolinensis +* +* Lacertidae Lacerta vivipara 54 H. Ora Ryukyu Archipelago MJ TK AM OK MY YY SE DA OG T'TW FJ Takydromus amurensis T. dorsalis T. smaragdinus T. tachydromoides +1 T. toyamai Scincidae At euchos aurus p ellop leurus +t C ry p tob I epharu s b outonii C. b. nigropunctatus Eumeces barbouri E. elegans E. kishinouyei E. latiscutatus +t E. marginatus E. okadae E. stimpsonii Emoia atrocostata Scincella boettgeri S. formosensis +2 S. vandenburghi + SERPENTES Typhlopidae Ramphotyphlops br aminus +*l +* Colubridae Achalinus formosanus A. f. chigirai A. spinalis +t A. werneri Amphiesma concelarum Am. ishigakiense Am. pryeri Am. vibakari Am. v. vibakari +1 Am. v. danioense + Calamaria Pavimentata C. p. miyarai C. pfefferi Cyclophiops herminae Cy. semicarinatus Dinodon orientale +t D. rufozonatum D. r. rufozonatum D. r. walli D. semicarinatum Elaphe carinata E. c. carinata E. c. yonaguniensis E. climacophora +t E. conspicillata +t E. quadrivirgata +1 E. taeniura E. t. friesi +* E. t. schmackeri Geographic faunal pattern of reptiles and amphibians of the Ryukyus 55 Ryukyu Archipelago MJ TK AM OK MY YY SE DA OG TW FJ Lycodon ruhstrati L. r. multifasciatus Opi sthot r opis kikuzatoi Pareas iwasakii Rhabdophis tigrinus R. t. tigrinus +l Elapidae Hemibungarus j aponicus H. j. japonicus H. j. boettgeri H. j. subsp. H. macclellandi H. m. iwasakii Viperidae A gki s tr o do n b I omhoffii +1 A. tsushimaensis + Trimeresurus elegans +* T. flavoviridis + T. mucrosquamatus +{' T. tokarensis Ovophis okinavensis + 1, Distributed in Kyushu (including the Osumi Group), 2, S.-L. Chen, unpublished data. regarded as the southern half of the Amami Group; Area IV, the Miyako Group; Area V the yaeyama Group; and Area VI, the Senkaku Group. Of these, Area I accommodates seven species of terrestrial reptiles, including one endemic snake (Trimeresurus tokarensis), and only a single amphibian species (Buergeria japonica). In Area II, L9 species of terrestrial reptiles and 12 species of amphibians are distributed, of which two reptiles (Goniurosaurw karoiwae splendens and Hemibungarus japonicus japonicus) and three amphibians (Rana amamiensis, Babina subaspera, and Rhacophorus viridis amamiensis\ are endemic to this region. Area III accommodates 3L terrestrial reptiles including six endemic species/subspecies (Geoemyda iaponica, Goniurosaurus k kuroiwae, G. k orientalis, G. k yamashinae, G. k toyamai, and Opisthotropis kifuzatoi), and 15 amphibians including four endemic species/subsp ecies (Rana narina, R. namiyei, B. holsti, and Rhacophorus v. viridis). Of the species/subspecies not strictly endemic to the Area III, 1.1. reptiles (Japalura polygonata polygonata, Ateuchosaurus pellopleurus, Eumeces barbouri, Talcydromus smaragdinus, Dinodon semicarinatwn, Cyclophiops semicarinatus, Amphiesma pryeri, Achalinus wemeri, Hemibungarus japonicus boettgeri, Trimeresurus flavoviridis, and Ovophis okinavensis) and five amphibians (Cynops ensicauda, Tllototriton andersoni, Hyla hallowellii, Rana okinavana, and R ishikawae) are exclusively shared with Area II, or Areas I and IL In Area Iv 19 terrestrial reptiles including three endemic species (Tatqtdronus toyanai, Calatnaria pfefferi, and Amphiesma concelarum) and three amphibians including one endemic subspecies (Bufo gargarizans miyakonis) are distributed. Area V accommodates 27 species/subspecies of terrestrial reptiles and L0 species of amphibians, of which lL reptiles (Cistoclemmys flavomarginata evelynae, Mauremys mutica kami, Eumeces stimpsonii, Talrydromus dorsalis, Calatnaria pavimentata miyarai, Pareas iwasakii, Etaphe carinata yonaguniensii, Amphiesma 56 H. Ore Table 2. Amphibians of lapan. Their occurrences in Taiwan and Fujian (southeastern continental China) are also indicated. Data were taken from Kuramoto (1996: for Japanese urodelans), Maeda & Matsui (1999: for Japanese anurans), and Zhao & Adler (1993: for Taiwanese and Fijian species), with modifications