TEXAS:THE ARACHNID STATE

Texas is the only state in the United States that is fortunate enough to have literature records of all 11 recognized ordinal groups (Beccaloni 2009) of the Class Arachnida reported from within its geographical boundaries.

Not only does the state of Texas have all groups represented, but if one draws a circle extending out just 200 miles (320 km) from the Texas Tech Llano River Field Station in Junction, one will find all 11 groups reported as naturally occurring – within just a four to five hour drive from Junction, one can find collection localities where every one of the recognized major ordinal groups of arachnids on the planet has been observed, collected, and/or reported. No other geographical region in the United States can boast this credential.

While most southern states in the U.S. have spiders, scorpions, ticks, mites, pseudoscorpions, solifugids, vinegaroons, and harvestmen, the representatives from several of the minor groups serve to set Texas apart from most other regions of the United States.

While poorly studied, the near microscopic Palpigrades are not uncommon in Texas. Two species (Prokoenenia wheeleri and Eukoenenia florenciae) are known from central and northeastern Texas (Rucker 1901; 1903a; 1903b). More significantly – living specimens of Prokoenenia wheeleri and Eukoenenia florenciae  have been collected from litter samples taken from several habitats surrounding the Junction Field Station. A more intensive collecting effort using additional Berlese funnels is planned for the June 2011 field work. 

The Amblypygids (or Whip spiders) with their extremely long antenniform legs-are found worldwide in the tropics and subtropics (Savory 1977; Weygoldt 2000; Beccaloni 2009). Quintero (1980:157) reported specimens of the amblypygid Phrynus operculatus from the Big Bend area of Texas as well as collection localities from Brewster and Val Verde counties (p. 131: Map 1). Cokendolpher & Reddell (1992:45) also reported an unidentified amblypygid from a sink on the grounds of the Seminole Canyon State Park in southern Val Verde County. More recently, specimens of Phrynus operculatus were collected from two locations (including Brewster County) in west Texas during 2010 by Angelo State University graduate student Travis Fisher (Arachnid Class of 2010) and by Kari McWest and Tom Anton at Sauceda, Big Bend Ranch State Park.

The Schizomid Stenochrus mulaki was first reported from the Rio Grande Valley of south Texas over 70 years ago (Gertsch 1940). This species was later assigned to the genus Schizomus by Reddell & Cokendolpher (1995). What is more significant is the more recent report of an undescribed genus and species of Protoschizomidae from a sink on the grounds of the Seminole Canyon State Park in southern Val Verde County (Cokendolpher & Reddell 1992). The presence of this undescribed species of Protoschizomidae so distant from the known distribution of other members of the family (Cokendolpher & Reddell 1992:44 – fig. 3) is not only of special interest, but deserving of additional study.

Due to their earlier “reputation for extreme rarity” and their unique “anatomical specializations”, Theodore Savory (1977:219) concluded that the Ricinuleids were the “most fascinating, the most intriguing and the most challenging members of the invertebrate world”. While Cryptocellus dorotheae has been known from south Texas for more than 70 years (Gertsch & Mulaik 1939) – it is important to note that an undescribed species of troglobitic ricinuleid from northern Coahuila less than 100 km from the Texas border at Del Rio was recently reported by Hendrickson et al. (2001:328). 

The presence of the Schizomid and Amblypygid species from the Seminole Canyon area near Comstock in conjunction with the undescribed species of Ricinuleid from nearby Coahuila serve to strengthen the importance of future arachnid studies throughout the Trans-Pecos region of Texas as well as the adjoining areas of the state of Coahuila. One of the primary goals in offering this course on the Biology of the Arachnids is to create awareness among students of the potential for future research opportunities offered by this nearby and unique geographical region.
While the neighboring states of Tamaulipas, Nuevo Leon, and Coahuila in northeastern Mexico share similar diversities of their arachnid fauna, Texas offers a truly unique opportunity for those interested in arachnids who reside in the United States.  Additionally, we are extremely fortunate to have the facilities and support of the Texas Tech University Llano River Field Station in Junction at our disposal to offer this course on the Biology of the Arachnids.

LITERATURE CITED
Beccaloni, J. 2009. Arachnids. University of California Press, Berkeley & Los Angeles, California, 320 pp.
Cokendolpher, J. C. & J. R. Reddell. 1992. Revision of the Protoschizomidae (Arachnida: Schizomida) with Notes on the Phylogeny of the Order. Texas Mem. Mus., Speleol. Monogr., 3: 31-74.
Gertsch, W. J. 1940. Two New American Whip Scorpions of the Family Schizomida. American Museum Novitates 1077: 1-4.
Gertsch, W. J. & S. Mulaik. 1939. Report on a New Ricinuleid from Texas. American Museum Novitates 1037: 1-5.
Hendrickson, D. A., J. K. Krejca & J. M. Rodríguez Martinez. 2001. Mexican Blindcats genus Prietella (Siluriformes: Ictaluridae): an Overview of Recent Explorations. Environmental Biology of Fishes, 62: 315-337.
Quintero, D. 1981. The amblypygid genus Phrynus in the Americas (Amblypygi, Phrynidae). Journal of Arachnology 9: 117–166.
Reddell, J. R. & J. C. Cokendolpher. 1995. Catalogue, Bibliography, and Generic Revision of the Order Schizomida (Arachnida). Texas Mem. Mus., Speleol. Monogr. No. 4: 1-170.
Rucker, A . 1901 . The Texas Koenenia . Amer . Nat ., 35: 615-630 .
Rucker, A . 1903a . A new Koenenia from Texas . Quart . J . Micros . Sci ., 47: 215-231 .
Rucker, A . 1903b . Further observations on Koenenia . Zool . Jahrb . Syst ., 18: 401-434 .
Savory, T. 1977. Arachnida, 2nd edition. Academic Press, New York, New York, 340 pp.
Wygoldt, P. 2000. Whip spiders (Chelicerata: Amblypygi). Their biology, morphology and systematics. Apollo Books, Stenstrup, Denmark. 163 pp.