April 1990 Asiatic Herpetological Research Vol. 3, pp. 67-84 On the Independence of the Colchis Center of Amphibian and Reptile Speciation BORIS S. TUNIYEV 1 ^Causasian State Biosphere Reserve, Sochi, USSR Abstract. -The Colchis region of Western Transcaucasia is characterized by a rather uniform thermal regimen, corresponding to a subtropical climate. The Colchis forests contain an extraordinary abundance and diversity of tree, shrub, and vine species. The herpetofauna of the Colchis forests is surprisingly poor, despite its uniqueness. Key Words: Amphibia, Reptilia, USSR, Caucasus, biogeography. Introduction Often they are inhabited by the same species. The question is whether this fauna The herpetofauna of Western has appeared from the west or is it the Transcaucasia is not homogeneous, due to remainder of the fauna that has populated the different age and genesis of the species densely the shores of the Black Sea at one distributions. Along with autochtonous time. It is impossible to answer these and endemic forms, one can find species questions at the present level of our whose main areas of distribution are in the knowledge. But even now I can definitely European part of the USSR and in the say that this fauna by its origin, has nothing Eastern Mediterranean. At the same time, a in common with the faunas in other regions number of species which have main of the Caucasus." distributional centers in the Colchis occur beyond the bounds of Western In 1912, Satunin divided the Caucasian Transcaucasia, in other parts of the Isthmus into five subregions and 11 Caucasian Isthmus. For these reasons, it is districts, including the Colchis in the West- necessary to define the Colchis Transcaucasian district of the Littoral herpetofauna and to determine its place in subregion. the fauna of reptiles and amphibians of the Caucasian Isthmus as a whole. Among other merits of this work by Satunin, one cannot but mention the fact Research on this issue started with the that for the first time, he defined in an exact works of Nordmann (1840), Derjugin way the Colchis region proper. He defined (1899), Silantyev (1903), Brauner (1905), the northern border as the spurs of the Main and Nesterov (1911). However, the first Caucasian Range up to the basin of the well-grounded definition of the fauna in Tuapse River, the southern border as the question from a zoogeographical point of Pontic Range, and the eastern border as the view was presented in the works of Arsijanskij Range. The valley of the Rioni Satunin (1912). Satunin wrote in 1910, River and the adjacent southern slopes of "So far I cannot say much about the genesis the Main Range were defined as the central of the fauna of this region called Western part of the region. Satunin emphasized the Transcaucasia. This country with its depauperate herpetofauna of this region on evergreen plants and scanty fauna one hand, and the presence of endemic resembles a piece of the Mediterranean in species such as Vipera kaznakowi and the narrow sense of the word. True, here Bufo verrucosissimus on the other hand. are endemic species and forms, but not a single genus of vertebrate is unrepresented Nikolsky (1911) assigned the entire in the countries of the Mediterranean. Caucasus, excluding eastern Precaucasia, © 1990 by Asiatic Herpetological Research Vol. 3, p. 68 Asiatic Herpetological Research April 1990 to the Mediterranean. However, he could Colchis, however, was not distinguished as not differentiate the forest and the alpine an independent center of speciation in this belts of the Greater Caucasus, because of work. the absence of data. Scherbak (1981) included the Colchis in Results and Discussion the Caucasian Region of the Mediterranean Province. He suggested that the typical Investigations of the last decades made it species of the region were Mertensiella possible to add the majority of the species caucasica, Pelodytes caucasicus, Lacerta of the Colchis herpetofauna to an overall saxicola-complex and others. However, picture of Colchis faunal distributions the Colchis proper was again not (Turov 1928; Bartenev and Reznikova distinguished as an independent center of 1935; Khozatsky 1941; Milyanovskiy herpetofaunal formation. 1957; Bannikov et al. 1977; Negmedzyanov and Bakradze 1977; Orlova For the analysis of the herpetofauna of 1973, 1978a, 1978b; Golubev 1980, 1985; the Colchis proper, it is necessary to Tuniyev 1983, 1985). In addition there has exactly define the term "the Colchis been a revision of the taxonomic status of phytolandscapes", and to decide what types such forms as Vipera kaznakowi of vegetation are universally recognized as (Vedmederja et al. 1986; Orlov and "Colchis types". Albov (1885) was the Tuniyev 1986a, 1990 this volume), Lacerta first to clearly depict plant landscapes of agilis (Peters 1960), L. derjugini the Colchis. He singled out a region, (Bartenev and Reznikova 1931; Orlova unique for Russia, of mountain limestone 1978a ; Bischoff 1982, 1984), L. saxicola flora which had been developing mainly (Darevsky 1967; Darevsky and Vedmederja autochthonously in a large refugium with 1977), Anguis fragilis colchicus (Lukina numerous endemic and relict species and 1965; Scherbak and Scherban 1980), and even genera. Kolakovskiy (1980) regarded others. the Colchis flora as basically forest and alpine-meadow, and suggested that its main Accumulation of this information along phytolandscapes had existed since old times with works on fossil amphibians and with changes only in the composition of reptiles of the Caucasus (Vekua et al. 1979; their edificators, except for the extinct Chkhikvadze 1981, 1983, 1984; Bakradze formation of evergreen subtropical forests and Chkhikvadze 1977; Zerova and in the lower mountain belt. The tertiary- Chkhikvadze 1984; Yefimov and relict character of the forest mesophile flora Chkhikvadze 1987) have made it possible and vegetation is fully revealed here due to to revise the zoogeography of the region. slight changes in this region's climatic conditions (Kuznetsov 1891). The most Darevsky (1957) singled out seven characteristic features of the tertiary-relict different groups of species and subspecies Colchis forest are: extraordinary of the herpetofauna in the Caucasus, based abundance and diversity of tree and shrub on their origin. Among the species species, impossibility of singling out the representatives of the region of interest to dominant species (which is also us, it is necessary to pay attention to characteristic of tropical forest with extreme Lacerta strigata (Asia Minor species), density of trees), abundance of vines and Emys orbicularis, Anguis fragilis, epiphytes, and almost total absence of grass Coronella austriaca, Elaphe quatuorlineates cover. All these attributes make the Colchis sauromates, Natrix natrix (European boreal forest similar in many aspects to a tropical species), Testudo graeca, Natrix tessellata rain forest (Pavlov 1984). According to (Mediterranean species), Pseudopus Sinskaya (1933), the Colchis forest apodus, Coluber najadum (east- vegetation underwent three main stages of Mediterranean species), and Lacerta development: the tropical forest; the forest saxicola, L. praticola, L. derjugini, L. of Colchis type, but rich and covering a media (autochthonous species). The wider area; and last, the modern Colchis April 1990 Asiatic Herpetological Research Vol. 3, p. 69 forest. grusinica, Natrix megalocephala, and Vipera kaznakowi are Colchis endemics in The Colchis type of vegetation includes a the broad sense of the word. number of phytocenoses differing in structure, composition, and ecological In addition to the Colchis endemics, peculiarities: it may be mixed there are three more ecological-geographical (polydominant), or may be presented by groups of amphibians and reptiles in the cenosis of one or two species, but the region. They have similar ecological common and obligatory attribute of characteristics (habitat first of all), and phytocenosis of the Colchis type is an overlapping geographic distributions. abundance of tertiary relicts. The area with Colchis type vegetation is characterized by 1. The East-Mediterranean group a rather monotonous thermal regimen, consists of Triturus cristatus karelini, to a corresponding subtropical climate, but Testudo graeca nikolskii (Fig. 1 ), Lacerta with highly diverse soils (Gulisashvili et al. media, L. praticola pontica, L. strigata, 1975). Pseudopus apodus tracius, Natrix tessellata, and Coluber najadum. This The herpetofauna of the Colchis forests group's distribution includes either the is surprisingly poor, despite its uniqueness. Balkans and the Caucasus or the Balkans, The species composition is different in the Crimea, and the Caucasus. According to southeastern and northwestern parts of the ecological characteristics, these are Colchis compared to the other portions of xeromesophiles or hemixerophiles whose its territory. Species such as Mertensiella spreading is related to dry foothills of caucasica, Lacerta clarkorum, L. parvula, Western Transcaucasia up to 200-300 m and L. mixta, whose distributions are above sea level with an annual sum of connected with forests growing on acid temperatures exceeding 5000°C. Thus, soils above volcanic rocks, are found on Testudo graeca, Pseudopus apodus, and the western slopes of the Adzharo- Coluber najadum occur in the Colchis on a Imeretinsky, Shavshetsky and Lazistansky narrow seaside strip of land with enclaves (Pontic) mountain ranges. Similarly, of Mediterranean vegetation from Tuapse to floristic endemics