Trichopetalum uncum Cook & Collins

Shear, William A., 2010, 2385, Zootaxa 2385, pp. 1-62 : 17-19

Trichopetalum uncum Cook & Collins

Figs. 11–13, Map 2

Trichopetalum uncum Cook & Collins, 1895:66 , fig. 51. Shear, 1972:277, figs. 500, 501.

Types: Male holotype from Bloomington, Indiana, said to be in USNM, but not located in 2000. According to Cook & Collins, the single male known to them was found in the same vial as Bollman’s type material of T. cornutum . The presently known distribution of uncum , with a single exception (Clarke Co., Illinois, see below), is well south of central Indiana.

Diagnosis: Easily distinguished from all other Trichopetalum species by the large lateral branch of the gonopod angiocoxite ( Figs. 11, 12).

Etymology: The species name, uncum , is a Latin adjective meaning “hooked, barbed,” and refers to the form of the gonopod angiocoxite.

Male from Marvel Cave, Stone Co., Missouri: Length, 7.2 mm, width, 0.75 mm. Color pale yellowish tan. Ocelli 3 in single row. Legpairs 3–7 enlarged, pairs 4, 5 the largest, pair 7 significantly larger than postgonopodal legs. Gonopods ( Figs. 11–13) robust, angiocoxite strongly bent posteriorly, broad in lateral view, with strong lateral branch; apex of coxite deeply divided. Colpocoxite ( Fig. 13) differing in form from that in T. lunatum , broader, without acute apical branch, fimbriate branch large, prominent. Ninth legs as in T. lunatum . Tenth and eleventh legpairs with coxal glands.

Female from Marvel Cave, Stone Co., Missouri: Length, 7.7 mm, width 0.80 mm. Similar to male in nonsexual characters.

Distribution: See Map 2 for selected records. Material examined: ARKANSAS: Sharp Co.: Center Cave, 2 mi E, 1 mi S of Center, 9 November 1974, V. McDaniel, male (FSCA). GEORGIA: Union Co. : Brasstown Bald, 4700’ asl, 27 May 1978, F. A. Coyle, male, female (VMNH). ILLINOIS: Clark Co.: Rocky Branch, 13 May 1949, H. Ross, male (INHS). KENTUCKY: Butler Co.: Ravine below Granny’s Rockhouse, 2.5 mi SE of Welch’s Creek, 23 February 1957, L. Hubricht, male (VMNH). MISSISSIPPI: Benton Co.: 1 mi W of Canaan, 27 February 1962, L. Hubricht, male, female (VMNH); Forrest Co.: 3.8 mi SE of McCallum, 1 November 1962, L. Hubricht, male, females (VMNH). MISSOURI: Dade Co.: Carrico Cave, 31 March 1965, B. Prasman, male (FSCA); Ripley Co.: Panther Cave, 16 mi NW of Doniphan, 11 September 1978, male (NCSM); Stone Co.: Marvel Cave, 2 April 1959, T. Barr, males, female (FSCA); Washington Co.: 1 mi W of Bliss, 14 November 1942, L. Hubricht, males, females (FSCA). OKLAHOMA: Muskogee Co.: Dresser Cove, 5 mi N of Ft. Gibson, no date, no collector, male (FSCA). SOUTH CAROLINA: Pickens Co. Sassafras Mtn., N35°06’, W82°77’, 30 December 2005, W. Reeves (WAS). TENNESSEE: Blount Co.: along Big Poplar Trail, Cades Cove, Great Smoky Mountains National Park, 23 May 1962, L. Hubricht, males (VMNH); Franklin Co.: Buck Creek Cove, 3 mi W of Anderson, 20 May 1963, L. Hubricht, male (VMNH); Knox Co.: 4 mi NW of Hall’s Crossroads, 20 May 1961, L. Hubricht, male (VMNH).

Literature Records: “several places in Washington and Logan Cos.” ARKANSAS ( Causey, 1951); Mammoth Cave National Park , Edmonson Co., KENTUCKY ( Causey, 1967) . Lewis and Hoffman (1997) report the species from caves in Jennings and Monroe Cos., INDIANA.

The northern boundaries of the distribution remain to be defined. Lewis and Hoffman (1997) suggest the type locality could be futher narrowed to Coon’s Cave, near Bloomington, since that was the label data in USNM collection #42, where the single specimen was found in company with T. lunatum (as T. cornutum ; Cook & Collins 1895). Clark Co., Illinois, is about on the latitude of Bloomington and on the border of Illinois with Indiana. This is the only find of uncum in the extensive collection of the Illinois Natural History Survey. There are no specimens of uncum in the Illinois collections of the Field Museum, Chicago, Illinois. The Clark Co. locality is also the type locality for T. stannardi (see below).

Trichopetalum uncum should be expected in northern ALABAMA, since it occurs nearby in Tennessee and is found in Georgia and Mississippi. Likewise it may occur in northern LOUISIANA . The single Oklahoma record indicates a slight chance of occurrence in northeastern TEXAS. On the North Carolina side of the Blue Ridge, this species seems to be replaced by T. dickbrucei , new species, and in the North Carolina piedmont by T. dux , but the single, recent record from South Carolina indicates that T. uncum could co-occur with either of the other species in SOUTH CAROLINA.

Notes: Ecological notes on labels are sparse, but collecting dates are obviously biased toward cooler times of the year. Again, deciduous leaf litter seems the preferred habitat on the surface. It appears that this species replaces T. lunatum in the south, but based on the Indiana records, the two may at some places be sympatric. In Marvel Cave, Missouri, uncum is sympatric with another trichopetalid, Causeyella dendropus ( Loomis, 1939) . The latter is a highly evolved troglobiont. While uncum shows a greater predeliction for troglophily than other Trichopetalum , signs of modification for an underground life are few and limited to a reduction in the number of ocelli (to 3 or fewer on each side; the usual number for epigean specimens is 6–8). However, the association with caves is not as strong as suggested by Lewis and Hoffman (1997); based on the records above, uncum is frequently found in surface habitats. For much of the species’ range, collecting has been much more thorough in caves than in appropriate surface habitats.