Systematics, conservation and morphology of the spider genus Tayshaneta (Araneae, Leptonetidae) in Central Texas Caves

Abstract

The spider genus Tayshaneta is revised based on results from a three gene phylogenetic analysis (Ledford et al. 2011) and a comprehensive morphological survey using scanning electron (SEM) and compound light microscopy. The morphology and relationships within Tayshaneta are discussed and five species-groups are supported by phylogenetic analyses: the anopica group, the coeca group, the myopica group, the microps group and the sandersi group. Short branch lengths within Tayshaneta contrast sharply with the remaining North American genera and are viewed as evidence for a relatively recent radiation of species. Variation in troglomorphic morphology is discussed and compared to patterns found in other Texas cave invertebrates. Several species previously known as single cave endemics have wider ranges than expected, suggesting that some caves are not isolated habitats but instead form part of interconnected karst networks. Distribution maps are compared with karst faunal regions (KFR’s) in Central Texas and the implications for the conservation and recovery of Tayshaneta species are discussed. Ten new species are described: Tayshaneta archambaulti sp. n., Tayshaneta emeraldae sp. n., Tayshaneta fawcetti sp. n., Tayshaneta grubbsi sp. n., Tayshaneta madla sp. n., Tayshaneta oconnorae sp. n., Tayshaneta sandersi sp. n., Tayshaneta sprousei sp. n., Tayshaneta vidrio sp. n. and Tayshaneta whitei sp. n. The males for three species, Tayshaneta anopica (Gertsch, 1974), Tayshaneta devia (Gertsch, 1974) and Tayshaneta microps (Gertsch, 1974) are described for the first time. Tayshaneta furtiva (Gertsch, 1974) and Tayshaneta uvaldea (Gertsch, 1974) are declared nomina dubia as the female holotypes are not diagnosable and efforts to locate specimens at the type localities were unsuccessful. All Tayshaneta species are thoroughly illustrated, diagnosed and keyed. Distribution maps are also provided highlighting areas of taxonomic ambiguity in need of additional sampling.

Reconciling Mining with the Conservation of Cave Biodiversity: A Quantitative Baseline to Help Establish Conservation Priorities

“…This is further aggravated by the fact that the rarity of these troglobitic species is questionable, as most remain unidentified to the species level, and their distribution ranges are poorly known [10,11]. For instance, many troglobites are considered rare in the absence of extensive surveys in the area, although sampling intensification often expands the distribution range of troglobitic species [7,59]. Our work thus suggests that the great emphasis on rare troglobitic species may be a poor allocation of scarce conservation resources, as shown for many other surrogate species [60].…”

Spiders in caves

“…A reduced number of eggs/cocoons (less than 10) was also documented for several troglobionts [28,50,[65][66][67]. For comparison, a number of eggs/eggsacs one order of magnitude higher was documented for troglophile species able to disperse outside the cave habitat [68,69].…”

“…In fact, recently numerous authors stressed the importance of protecting their habitats [4,67,91,93,104].…”

“…Furthermore, the current species hypothesis regarding speciose taxa are often far for being solid [62,67,88,92,94], which is a crucial factor hindering the conservation of cryptic and restricted species [108].…”

Life beneath the surface of the central Texan Balcones Escarpment: genus Anillinus Casey, 1918 (Coleoptera, Carabidae, Bembidiini): new species, a key to the Texas species, and notes about their way of life and evolution

“…Fish and Wildlife Service, Department of Interior 2000, Paquin and Hedin 2004, Ledford et al 2012). Central Texas harbors one of the richer and more distinctive cave faunas of North America and the world (Culver et al 2003, 2006).…”