Trilasma petersprousei, Shear, William A., 2010

Shear, William A., 2010, New species and records of ortholasmatine harvestmen from Mexico, Honduras, and the western United States (Opiliones, Nemastomatidae, Ortholasmatinae), ZooKeys 52, pp. 9-46 : 31-32

Trilasma petersprousei sp. n. Figs 162546

Types.

Female holotype (TMM) from Hoya de las Guaguas, 10 km south of Aquismón, San Luis Potosí, México, collected 29 August 1986 by Peter Sprouse.

Diagnosis.

Trilasma petersprousei sp. n. is a long-legged species, with long, thin pedipalps. The high tarsal count of the holotype (6, 12, 6, 8) and the presence of 12 false articulations in the second metatarsi also distinguish it from other species.

Etymology.

The species is named for the collector, Peter Sprouse of Zara Environmental, LLC, a noted explorer of Mexican caves who has collected many new species of troglobionts and troglophiles.

Description.

Female holotype: total length, 3.4, width, 1.9. Color pale tan to yellowish brown. Carapace arcuate, about 1.5X as wide as long, with complete lateral and posterior submarginal keels; pair of median keels connecting eye tubercle and innermost lateral hood process, lateral keels arising both on innermost and middle lateral hood processes. Two blunt lateral hood processes each about one-half as long as median hood process. Circumocular keels suppressed, but subocular portion obvious, eyes relatively large, bulging. Median hood process arising dorsally on eye tubercle, with nearly parallel sides, then converging distally, widest slightly beyond midlength, length 1.10, width 0.45; median keels of carapace continuing as rows of lateral tubercles on median hood process, about 20 lateral tubercles, linearly connected; about 15 dorsal tubercles present, connected complexly to one another and to lateral tubercles. Metapeltidium free, complete keel along anterior margin, 6 tubercles posterior to keel, connected to it by single branch each. Scute 1.8 long, 1.9 wide. All keels relatively low. Small keel cells present on areas 1-4; area 1 with 2-3 small cells in midline, area 2 with 4-6 small cells in transverse row less than ½ width of scute, area 3 with 5-6 small cells in midline, area 4 with 10-12 small cells in transverse row about ½ width of scute. Paired median scute spines not prominent, on areas 4, 5 only slightly larger than adjacent keel tubercles (Fig. 46).

Chelicerae (Fig. 16) with basal article 0.70 long, 0.23 wide, sparsely setose; second article 0.72 long, 0.20 wide. Palpus (Fig. 25) slender, with dense vestiture of clavate setae; trochanter with two prominent seta-bearing ventral tubercles; dimensions given in Table 8. Legs in order of length, 2 (14.05), 4 (9.43), 3 (5.90), 1 (5.73); metatarsus 2 with about 12 false articulations, femora without false articulations; tarsi 1-4 with 6, 12, 6(7), 9 articles respectively. Lengths of leg segments given in Table 8. Length/width ratios of femora, in order: 8.25, 36.8, 9.0, 28.2. Leg femora with typical ornamentation.

Genital operculum broadly rounded, separated from sternite by suture. Ovipositor typical of genus.

Notes.

While Trilasma petersprousei sp. n. has long, thin legs and palpi, it does not appear in any other way to be a troglobiont; the eyes are large and well-pigmented and it lacks the exaggerated median hood process of Trilasma sbordonii , a true troglobiont.

Hoya de las Guaguas (sometimes spelled Huahuas in Spanish) is an immense pit, 478 m (1565') deep, developed in limestone of the Sierra Huasteca, and located at 21°31'56'N; 99°02'01.15W, about 460 m (1500') asl. The entrance is large enough that sufficient light reaches the floor to sustain a plant community (P. Sprouse, pers. comm.).