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Many species of endemic aquatic organisms inhabit the springs and water-filled caves of the Edwards Plateau region of central Texas. Most have limited distributions, and their existence is dependent upon the availability of clean water from subterranean sources (the Edwards Aquifer and associated aquifers). The Edwards Plateau is composed of uplifted karst limestone; water percolates through the limestone, recharges the underground reservoirs, and re-emerges from a large number of springs. The biggest and most well known of these springs are located along the southern and eastern margins of the Edwards Plateau (the Balcones Escarpment) and include Barton Springs in the city of Austin (Travis County); San Marcos Springs in the city of San Marcos, southwest of Austin in Hays County; and Comal Springs in the city of New Braunfels, northeast of San Antonio in Comal County. North of the Colorado River (which flows through the city of Austin), a smaller aquifer system supplies water to the springs, creeks, and caves of Travis, Williamson, and Bell counties at the northeastern edge of the plateau. Sweet (1982) provides a useful overview of the hydrogeology of the region; also see Abbott (1975), various authors in Abbott and Woodruff (1986), and Veni (1988). Throughout the southern and eastern portions of the Edwards Plateau, numerous populations of salamanders of the genus Eurycea are known, and all are restricted to caves with water and/or the vicinity of spring outflows (Hamilton, 1973; Sweet, 1982, 1984; Chippindale, 2000; Chippindale et al., 2000). Here we include in the genus Eurycea two species formerly assigned to the genus Typhlomolge, based on the phylogenetic work conducted by Chippindale et al. (2000) and discussed below. Nearly all populations of Eurycea in central Texas are paedomorphic (i.e., attain reproductive maturity without undergoing metamorphosis ). The only known exceptions are a few transforming populations in mesic canyons of the Hill Country, in the southwestern Edwards Plateau (Bogart, 1967; Sweet, 1977b). All members of the group are aquatic, although transformed individuals may venture short distances onto land (Sweet, 1977b, 1978b). Taxonomic History The taxonomic history of the Texas Eurycea is somewhat complicated. Chippindale et al. (2000) provide a systematic revision that includes a detailed history and list of synonymies as well as the description of three new species, and Chippindale (2000) outlines past and current perspectives on species diversity in the group. Hillis et al. (2001) describe another new species (Austin blind salamanders [Eurycea waterlooensis ]) and provide further taxonomic revisions. Here we provide a brief summary of species that were recognized prior to molecular-based systematic studies of the group. In 1895, large aquatic plethodontid salamanders that exhibited highly cave-associated morphological features (e.g., lack of pigmentation, wide, flattened skulls, vestigial eyes, elongated limbs, and reduced numbers of vertebrae) were discovered in the outflows of a 58-meter-deep artesian well drilled at San Marcos, Hays County. Stejneger (1896) described this species as Typhlomolge rathbuni (Texas blind salamanders). Decades later, the status of the genus Typhlomolge became controversial when Mitchell and Reddell (1965) and Mitchell and Smith (1972) provided evidence that T. rathbuni should be considered a member of the genus Eurycea. This view was contradicted by Potter and Sweet (1981), who argued for continued recognition of the genus Typhlomolge as distinct from Eurycea. However, molecular phylogenetic evidence supports synonymization of Typhlomolge under Eurycea (Chippindale, 1995, 2000; Chippindale et al., 2000; Hillis et al., 2001; see discussion below). Bishop and Wright (1937) described the next member of the group, Eurycea neotenes (Texas salamanders; see also Bruce, 1976), from a spring at Helotes, Bexar County, north of San Antonio. Until recently, nearly all populations of spring and cave Eurycea in the Edwards Plateau region were assigned to this species; now (as discussed below) Texas salamanders are restricted in distribution to springs in the general area of the type locality (Chippindale et al., 2000). Eurycea nana (San Marcos salamanders) were described by Bishop (1941a; see also B.C. Brown, 1967b) from San Marcos Springs, Hays County. Despite confusion in the literature regarding the distribution of this species, it is clear that these animals occur only at the type locality (Chippindale et al., 1998). Smith and Potter (1946; see also B.C. Brown, 1967a) described E. latitans (Cascade Caverns salamanders) from Cascade Caverns, Kendall County (northeast of San Antonio), and Burger et al. (1950) described E. pterophila (Fern Bank salamanders) from 193 TW E NTY-S EVE N Conservation of Texas Spring and Cave Salamanders (Eurycea) PAUL T. CHIPPINDALE AND ANDREW H. PRICE Fern...

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