Trilasma chipinquensis, 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 : 33-34

Trilasma chipinquensis sp. n. Figs 172650

Types.

Female holotype (AMNH) from Chipinque Mesa, Monterrey, Nuevo Léon, México, collected 24 June 1969 by Stewart B. Peck.

Diagnosis.

The paired median area tubercles are strongly developed in this species and project well above the level of the keels. Like trispinosum sp. n., there is a single false articulation in female femur 4, but trispinosum sp. n. has 3 lateral hood processes, while chipinquensis sp. n. has 2.

Etymology.

The species epithet, an adjective, refers to the type locality.

Description.

Female holotype: total length, 2.7, width, 1.5. Color dark brown, nearly black (possibly artifact of preservation). 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 strongly developed, but subocular portion easily seen in dorsal view, eyes relatively small. Median hood process arising dorsally on eye tubercle, with nearly parallel sides, only slightly converging distally, length 0.95, width 0.40; median keels of carapace continuing as rows of lateral tubercles on median hood process, about 16 lateral tubercles, linearly connected; about 6 dorsal tubercles present, connected in a single row to one another but not to lateral tubercles. Metapeltidium free, complete keel along anterior margin, 6 tubercles posterior to keel, connected to it by single branch each. Scute 1.7 long, 1.5 wide. All keels well elevated above dorsum. Small keel cells present on areas 2-4; areas 2, 3 with 5-8 small cells in midline, area 4 with 10-12 small cells in transverse row about 2/3 width of scute. Paired median scute spines prominent, on all areas significantly larger than adjacent keel tubercles, standing well above keels; pair of spines also present on metapeltidium (Fig. 50).

Chelicerae (Fig. 17) with basal article 0.64 long, 0.21 wide, sparsely setose; distal article 0.60 long, 0.19 wide. Palpus (Fig. 26) relatively slender, with dense vestiture of clavate setae; trochanter with two prominent seta-bearing ventral tubercles; dimensions given in Table 9. Legs in order of length, 2? (-), 4 (5.62), 3 (4.66), 1 (4.20); metatarsi without false articulations, femora 4 without single false articulation; tarsi 1-4 with 5, -, 7, 6 articles respectively (tarsi 2 missing). Lengths of leg segments given in Table 9. Length/width ratios of femora, in order: 5.56, 12.86, 5.56, 7.60. Leg femora with typical ornamentation.

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

Notes.

The holotype female was mentioned and briefly described by Shear and Gruber (1983). The present examination resulted in some different observations, primarily in that I could not see the false articulation of the second femur observed in 1983. The second leg is absent from the left side, and broken off at the tibia-metatarsus joint on the right.

Chipinque Mesa is a ridge of the Sierra Madre Oriental overlooking the city of Monterrey, to the north. Approximate coordinates are 25°36'29.43N; 100°21'18W; elevation at the top of the ridge is 1524 m (5000'). Chipinque Mesa is now a part of the Parc Nacional Cumbre and is a popular sight-seeing destination for visitors to Monterrey. It is densely forested in pines.