Redefining the Type Locality and Range of the Tarantula, Aphonopelma hentzi
A total of 18 tarantula species, all currently assigned to the genus Aphonoplema, have been described from the south-central United States; an area encompassing Arkansas, Louisiana, Oklahoma, and Texas. Aphonopelma hentzi was the first tarantula species to be described from the region as well as all of North America (Girard, 1854; Smith, 1995). Most of the remaining Aphonoplema species from this four-state area were described by Chamberlin and Ivie (1939), Chamberlin (1940), and Smith (1995). These authors relied heavily on very small numbers of specimens for their descriptions, limiting consideration of individual variation, and applied taxonomic characters that possess little descriptive value (Prentice, 1997). Along with issues regarding morphological descriptors, inaccurate assessments of species occurrence have further confounded a clear understanding of Aphonoplema taxonomy.
Aphonoplema hentzi was described by Girard (1854) from specimens collected along the route of Randolph B. Marcy’s 1852 exploration of the Red River in Oklahoma and Texas (Marcy, 1854). Smith (1995), in an assessment of the genus, was unable to relocate Girard’s type specimen and subsequently designated a male neotype and a female paratype for the species using specimens collected from central Oklahoma. In an attempt to address the original locality of Girard’s type, Smith (1995) states that, even after examining Marcy (1954), “we still have only a very approximate idea of the likely location site” and that “my own view is that the material was collected in 1851…in the region of McLain County in late August.” The current male neotype and female paratype of A. hentzi were collected from Garfield County, Oklahoma. Smith (1995) also designated specimens from Cherokee, Pawnee, Payne, and Tulsa Counties, Oklahoma as A. hentzi.
Contrary to Smith’s (1995) assertion of geographic indeterminabilty, the general vicinity of Girard’s A. hentzi type locality is denoted in Girard (1854) and Marcy (1854). Girard (1854) writes that the type specimen of A. hentzi, a female, was collected on May 17, 1852 from “an open, barren prairie between Camps 2 and 3.” According to Marcy (1854), the Red River expedition was to begin at the mouth of Cache Creek in southwestern Oklahoma. The expedition arrived at this point on May 13, 1852 and established camp. The party departed May 16, 1852, traveled just under 24 km between Cache Creek and the Red River, establishing their second camp. On May 17, 1852, the expedition traveled 17.7 km, and spent the night near a branch of Cache Creek, their third camp. This information places the original type locality of A. hentzi in the southwestern one-quarter of Cotton County, Oklahoma just north of the Red River. Girard (1854) states that other specimens, which he attributed to A. hentzi, were later taken by Marcy’s party “on the 28th of June, near the head of south fork of Red river.” That date places the expedition along the eastern edge of the Llano Estacado in the panhandle of northern Texas close to the Prairie Dog Town Fork of the Red River. This latter locality is the first published record of A. hentzi in Texas.
Chamberlin (1940) considered A. hentzi to be the most common tarantula along the valley of the Red River in Arkansas and Oklahoma ranging “northward from Arkansas, where it is abundant, into Kansas. This species formerly wide-range was reduced over time as additional Aphonopelma species were designated across the south-central United States. Smith (1995) later defined the range of A. hentzi as restricted to central and northern Oklahoma. That range reduction is not currently justified.
Based on information presented herein, southern Oklahoma and portions of northern Texas should be incorporated into the species distribution. Work by Rossman (1984) in Louisiana, Janowski-Bell (2001) in Missouri, and Warriner (2008) in Arkansas, indicates that A. hentzi should be considered the predominant tarantula species in all three of the aforementioned states.
Both Murray (2006) and Hamilton (2009), through morphological and molecular assessments, propose a wide range for A. hentzi from portions of Colorado and New Mexico, across Oklahoma, into southern Kansas, southern Missouri, Arkansas, northern Louisiana, and a large swath of Texas. This extensive distribution overlays the type localities of several other Aphonopelma species, many of which likely represent synonyms of A. hentzi. A significant amount of work is needed to clarify the geographic and taxonomic relationships among A. hentzi and its congeners in the south-central United States.
- Chamberlin, R. V. 1940. New American tarantulas of the family Aviculariidae. Bulletin of the University of Utah 30:1-39.
- Chamberlin, R. V. & W. Ivie. 1939. New tarantulas from the southwestern states. Bulletin of the University of Utah 29:1-17.
- Girard, C. 1854. Arachnidians. Pages 262-263 in Exploration of the Red River of Louisiana, in the year 1852: with reports of the natural history of the country, with numerous illustrations (R.B. Marcy and G.B. McClellan, editors). A.O.P. Nicholson, Washington, D.C.
- Hamilton, C.A. 2009. Determining the phylogeographic dynamics of the edge relationships between Aphonopelma hentzi (Girard) and its neighbors along the Colorado River Basin (Araneae, Mygalomorphae, Theraphosidae). M.S. thesis. University of Texas, Arlington.
- Janowski-Bell, M.E. 2001. Ecology of an American tarantula, Aphonopelma hentzi (Girard) (Theraphosidae). Ph.D. dissertation, University of Missouri, Columbia.
- Marcy, R.B. 1854. Exploration of the Red River of Louisiana, in the year 1852: with reports of the natural history of the country, with numerous illustrations. A.O.P. Nicholson, Washington, D.C.
- Murray, E.A. 2006. Systematics of Aphonopelma (Theraphosidae) from the south-central United States, as determined from molecular and morphological data. M.S. thesis, Kansas State University, Manhattan, Kansas.
- Prentice, T.R. 1997. Theraphosidae of the Mojave Desert west and north of the Colorado River (Araneae, Mygalomorphae, Theraphosidae). Journal of Arachnology 25:137-176.
- Rossman, D.A. 1984. Distribution of the tarantula Dugesiella hentzi (Girard) in Louisiana. Proceedings of the Louisiana Academy of Sciences 47:52-53.
- Smith, A. M. 1995. Tarantula spiders: tarantulas of the U.S.A. and Mexico. Fitzgerald Publishing, London.
- Warriner, M. 2008. Distribution and taxonomic status of tarantulas in Arkansas (Theraphosidae: Aphonopelma). Journal of the Arkansas Academy of Science 62:107-114.