Revision of genus Texoreddellia Wygodzinsky, 1973 (Hexapoda, Zygentoma, Nicoletiidae), a prominent element of the cave-adapted fauna of Texas.

While many cave-adapted organisms tend to be endemic to single locations or restricted to single karstic regions, the troglobitic silverfish insects of genus Texoreddellia can be found in scores of different cave localities that cover a range of nearly 160,000 km2. They are among the most important and common representatives of the cave-adapted fauna of Texas and Coahuila, in northern Mexico. Using morphological and mitochondrial gene sequence data, we have corroborated the presence of at least six different species within the genus and provided species identifications to populations inhabiting 153 different cave locations. Results show that species ranges are larger than previously reported and that ranges tend to greatly overlap with each other. We have also found that different species of Texoreddellia commonly inhabit the same cave in sympatry. Data supports that some species of Texoreddellia can easily disperse through the extensive network of cracks, fissures and smaller cavities near the surface and epikarst.

Up high and down low: Molecular systematics and insight into the diversification of the ground beetle genus Rhadine LeConte.

Rhadine LeConte is a Nearctic genus of flightless ground beetles that is poorly studied despite its relevance to evolutionary studies of subterranean fauna. Adults are notable for their slender and leggy habitus and the wide variety of habitat preferences among species, with several known only from mountaintops while others are restricted to caves or more general subterranean habitats. In central Texas, USA there are several cave endemics relevant to conservation. Here we present the first phylogenetic hypothesis for the overall structure of the genus with an emphasis on the troglobites in central Texas. We infer the phylogeny of Rhadine from ∼2.4-kb of aligned nucleotide sites from the nuclear genes, 28S rDNA and CAD, and the mitochondrial gene COI. These data were obtained for 30 species of Rhadine as well as from members of their putative sister group, Tanystoma Motschulsky. Results reveal that Rhadine is polyphyletic, and morphological characters that have been traditionally used to classify the genus into species groups are shown to be convergent in many cases. Rhadine aside from two species of uncertain placement is composed of two major clades, Clades I and II that both include epigean and subterranean species in very unequal proportions. Clade I is primarily composed of subterranean species, and Clade II includes many epigean species and high altitude montane endemics. A clade of troglobitic, cave-restricted species in Texas includes several species of large-eyed cave Rhadine. The slender habitus typical of some species [e.g., R. exilis (Barr and Lawrence), R. subterranea (Van Dyke), R. austinica Barr] evolved independently at least three times. Major biogeographic and evolutionary patterns based on these results include: troglobitic species north of the Colorado River in Texas (that also lack lateral pronotal setae) are found to comprise a monophyletic group, beetles in caves south of the Colorado River likely form another monophyletic group, and the "species pairs" of troglobitic Rhadine known to occur in the same caves are not resolved as each other's sister group, suggesting that these caves were colonized independently by more than one lineage of Rhadine. Our divergence time estimates support a Miocene age for the split between Clade I and II Rhadine and indicate that all subterranean Clade I Rhadine began diversifying in the late Miocene-early Pliocene, contemporary with cave formation in the Balcones Escarpment.

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.

The Texas fauna of the genus Anillinus Casey, 1918 includes three previously described species (A. affabilis (Brues), 1902, A. depressus (Jeannel), 1963 and A. sinuatus (Jeannel), 1963) and four new species here described: A. acutipennis Sokolov & Reddell, sp. n. (type locality: Fort Hood area, Bell County, Texas); A. comalensis Sokolov & Kavanaugh, sp. n. (type locality: 7 miles W of New Braunfels, Comal County, Texas); A. forthoodensis Sokolov & Reddell, sp. n. (type locality: Fort Hood area, Bell County, Texas); A. wisemanensis Sokolov & Kavanaugh, sp. n. (type locality: Wiseman Sink, Hays County, Texas). A key for identification of adults of these species is provided. The fauna includes both soil- and cave-inhabiting species restricted to the Balcones Fault Zone and Lampasas Cut Plain and adjacent areas underlain by the Edwards-Trinity Aquifer. Based on morphological and distributional data, we hypothesize that four lineages of endogean Anillinus species extended their geographical ranges from a source area in the Ouachita-Ozark Mountains to the Balconian region in central Texas. There the cavernous Edwards-Trinity aquifer system provided an excellent refugium as the regional climate in the late Tertiary and early Quaternary became increasingly drier, rendering life at the surface nearly impossible for small, litter-inhabiting arthropods. Isolated within the Edwards-Trinity aquifer system, these anilline lineages subsequently differentiated, accounting for the currently known diversity. The paucity of specimens and difficulty in collecting them suggest that additional undiscovered species remain to be found in the region.