Country distribution from AmphibiaWeb's database: United States
Eurycea neotenes Bishop and Wright, 1937
Paul T. Chippindale1
1. Historical versus Current Distribution. Texas salamanders (Eurycea neotenes) were described by Bishop and Wright (1937) from a spring at Helotes, Bexar County, north of the city of San Antonio. In subsequent years, many spring and cave populations from throughout the Edwards Plateau region of central Texas were assigned to this species (e.g., B.C. Brown, 1942, 1950, 1967a; Schmidt, 1953; Conant, 1958a, 1975; Baker, 1961; Mitchell and Smith, 1972; Sweet, 1977a, 1978a,b, 1982, 1984; Dixon, 1987; Conant and Collins, 1991; Behler and King, 1998; Petranka, 1998). These identifications were based primarily on the high degree of morphological similarity among individuals from many populations, especially those inhabiting springs.
Chippindale (1995, 2000) and Chippindale et al. (1993, 1998, 2000) used molecular and morphological data to assess species boundaries in the central Texas Eurycea. Allozymes and mitochondrial sequences revealed extensive genetic subdivision within what had been considered E. neotenes, and Chippindale et al. (2000) restricted the distribution of this species to several springs at and near the type locality. Most references to E. neotenes in the literature involve populations that Chippindale et al. (2000) considered Fern Bank salamanders (E. pterophila) or members of the E. latitans or E. troglodytes species complexes. Other species that formerly were considered E. neotenes are Barton Springs salamanders (E. sosorum), E. sp. 1 (Comal Springs), Jollyville Plateau salamanders (E. tonkawae), Georgetown salamanders (E. naufragia), and Salado salamanders (E. chisholmensis). Based on phylogenetic analyses, E. neotenes is a member of the southeastern Edwards Plateau subgroup of Texas Eurycea (Chippindale, 1995, 2000; Chippindale et al., 2000), and appears to be restricted to several springs in Bexar and Kendall counties.
2. Historical versus Current Abundance. Texas salamanders may be common at spring outflows, but their distribution appears to be limited and patchy.
3. Life History Features.
A. Breeding. Reproduction is aquatic.
i. Breeding migrations. Unlikely to occur.
ii. Breeding habitat. Unknown; closely related species are thought to deposit eggs in gravel substrates. Bogart (1967) described courtship and oviposition in Texas salamanders; in the laboratory, eggs were deposited on a variety of substrates.
i. Egg deposition sites. In the laboratory, eggs from an individual that might represent this species (see "Clutch size" below) were either free or attached to twigs and glass surfaces (Barden and Kezer, 1952).
ii. Clutch size. Barden and Kezer (1952) artificially induced egg laying in an individual that may represent this species; 12 eggs were produced in a 10-d period.
C. Larvae/Metamorphosis. Cascade Caverns salamanders are paedomorphic, and natural metamorphosis is unknown. Kezer (1952) described thyroxin-induced metamorphosis in individuals from a locality in Bexar County, which he considered to be Texas salamanders (E. neotenes). It is likely that the populations with which he worked actually belong to the E. latitans complex, based on their geographic location. Barden and Kezer (1944) described eggs and egg-laying by a captive individual from one of these populations. Bogart (1967) described oviposition and egg development.
D. Juvenile Habitat. Probably similar to adult habitat.
E. Adult Habitat. Completely aquatic. Known only from the immediate vicinity of spring outflows, under rocks and leaves and in gravel substrate. Water temperatures in springs of the Edwards Plateau are relatively constant throughout the year and typically range from 18–20 ˚C or slightly warmer near the fault zone at the Plateau's edge (Sweet, 1982). Sweet (1982) provided a comprehensive distributional analysis of the central Texas Eurycea and discussed hydrogeology of the region in relation to salamander distribution.
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. In 1990, P. Chippindale, D. Hillis, A. Price, and D. Bell visited the type locality of this species, a spring at the headwaters of Helotes Creek, Bexar County. The landowner informed us that the spring had been dry for approximately 2 yr and had only started to flow again days earlier. We found dozens of extremely thin salamanders in the spring pool (some dead and dying); presumably they had retreated into subterranean habitat while the spring was dry. Although this may not constitute true aestivation, it indicates that this species can survive temporary drying of surface springs.
I. Seasonal Migrations. Unlikely to occur.
J. Torpor (Hibernation). Probably active throughout the year.
K. Interspecific Associations/Exclusions. Unknown.
L. Age/Size at Reproductive Maturity. In a morphometric analysis of some Edwards Plateau Eurycea (Chippindale et al., 1993), average SVL of topotypical Texas salamanders that were presumed to be adult was 32.2 mm. However, Chippindale et al. (1993) probably did not include the smallest reproductively mature specimens in their analysis, and no rigorous studies of reproductive biology have been conducted for this species.
M. Longevity. Unknown.
N. Feeding Behavior. Prey probably consists mainly of small aquatic invertebrates, but no detailed feeding studies of this species have been conducted. Whiteworms were accepted in the laboratory (Bogart, 1967).
O. Predators. Unknown.
P. Anti-Predator Mechanisms. Secretive.
Q. Diseases. Hunsaker and Potter (1960) documented mortality due to "red-leg" disease caused by infection with bacteria (Pseudomonas hydrophila) for a population in the vicinity of the type locality.
R. Parasites. Unknown.
4. Conservation. Most references to Texas salamanders in the literature involve populations that are now considered members of the E. latitans or E. troglodytes species complexes. In fact, Texas salamanders appear to be restricted to several springs in Bexar and Kendall counties. These salamanders may be common at spring outflows, but their distribution appears to be limited and patchy. Despite this, they receive no protection by either the State of Texas (www.tpwd.state.tx.us) or by the Federal Government .
1Paul T. Chippindale
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 Dec 2018.
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