The Balcones Escarpment of south-central Texas is the eroded topographic expression of an en echelon fault zone where Cretaceous carbonates have been modifi ed by karst processes infl uenced by structural and stratigraphic controls. While the modern confi ned Edwards Aquifer fl ows through cavernous voids at the base of the escarpment, air-fi lled caves perched in the escarpment are relicts of paleoaquifer hydrology. The structural geology of the Balcones Escarpment and the phylogeography of its endemic cave spiders provide mutually informative frameworks from which to establish relative dates for the activation of discrete groundwater recharge areas. The mitochondrial genetic variability of troglobitic spiders is correlated with the structural elements of the Balcones fault zone in and around the San Antonio relay ramp. Older (basal) genetic lineages occur in structurally high, mature karst terrains, while the younger (derived) lineages occur in structurally low, emergent karst terrains. Based on mitochondrial deoxyribonucleic acid (mtDNA) data, Cicurina diversity is interpreted as the product of the progressive availability of vadose zone habitat as discrete recharge areas have developed. Genetics analysis was funded by the La Cantera Development Corporation and the U.S. Fish and Wildlife Service. Cave access was graciously granted by many private landowners, the USAA Corporation, Mabe Inc., the University of Texas at San Antonio, and the Texas Department of Transportation. We thank all of our caving partners for their time and effort. This paper benefi ted from reviews by S.J. Taylor and J.M. Sharp Jr., and graphics assistance by K.M. White. Where required, all specimens were collected by permit. (75)90084-0. Barr, T.C., 1968, Cave ecology and the evolution of troglobites: Evolutionary Biology, v. 2, p. 35-102. Brower, A.V.Z., 1994, Rapid morphological variation and convergence among races of the butterfl y Heliconius erato inferred from patterns of mito chondrial DNA evolution:

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Three eyeless species belonging to the spider genus Cicurina Menge are known from five caves located south of Austin, Travis County (Texas, United States). Because adult female cave-dwelling Cicurina are not common, and adult males rarely collected, these species were described from a very small sample of individuals (nine females). Recent collections have allowed the examination of a larger series of specimens, providing an opportunity to assess intraspecific variability. This has resulted in the synonymy of C. cueva Gertsch and C. reyesi Gertsch with Cicurina bandida Gertsch. The synonymy is supported by both female and male morphology; the male of the species is described for the first time. Cicurina bandida is now known from ~20 caves, restricted to a 10 km × 30 km area. Cicurina cueva was proposed to be listed as an endangered species. Because of the special conservation status of troglobitic Cicurina, modifications of the original species hypothesis are fertile grounds for confrontation between conservationists and proponents of development. Taxonomy is a dynamic science that progresses by proposing new scientific hypotheses and this conflicts with conservation principles that are embedded in a static framework. The criteria used to assign species a particular conservation status should be based on the best available evidence, and not limited by political considerations. Long-term conservation goals can only be achieved when based on a robust taxonomy, which is still largely unavailable for most Texas cave arthropods.

We report two new occurrence records for Jollyville Plateau Salamanders, Eurycea tonkawae Chippindale, Price, Wiens & Hillis, 2000, from an urbanized watershed in Travis County, Texas, USA. Eurycea tonkawae is listed as federally threatened under the Endangered Species Act of 1973 due to threats from urbanization, including degradation of water quality and quantity. These new records fill a distributional gap within its known range, highlight the importance of surveying historically neglected areas, identify unprotected populations, and encourage the discovery of new populations.

Urban expansion has contributed to the loss of habitat for range restricted species across the globe. Managing wildlife populations within these urban settings presents the challenge of balancing human and wildlife needs. Jollyville Plateau Salamanders (Eurycea tonkawae) are a range restricted, federally threatened, species of neotenic brook salamander endemic to central Texas. Almost the entire geographic range of E. tonkawae is embedded in the Austin, Cedar Park, and Round Rock metropolitan areas of Travis and Williamson counties, Texas. Among E. tonkawae occupied sites, Brushy Creek Spring has experienced some of the most extensive anthropogenic disturbance. Today the site consists of small groundwater outlets that emerge in the seams within a concrete culvert underlying a highway. Salamanders persist within this system though they are rarely detected. Here, we model the occurrence of salamanders within the surface habitat of Brushy Creek Spring using generalized linear models. In the absence of available data regarding the amount of water that is discharged from the spring, we use accumulated rainfall as a proxy for discharge to estimate salamander abundance. Additionally, we present evidence of reproduction, recruitment, and subterranean movement by E. tonkawae throughout this site. Infrastructure maintenance is inevitable at Brushy Creek Spring. We intend for our results to inform when maintenance should occur, i.e., during environmental conditions when salamanders are less likely to be observed in the surface habitat, to avoid unnecessary impacts to this federally threatened species.