Trilasma hidalgo, 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 : 35-36

Trilasma hidalgo sp. n. Figs 182740, 4151

Trilasma bolivari Goodnight & Goodnight, 1945b (not 1942), p. 8, in part only.

Type.

Male holotype (TMM) from El Chico, Pachuco, Hidalgo, México, collected 1 January 1976, no collector named.

Diagnosis.

This species is closest to Trilasma bolivari sp. n., but differs from it in having fewer small cells on the scute, shorter, stouter legs, and less prominent scute area tubercles. In addition the dorsal tubercles on the median hood process of Trilasma bolivari sp. n. are much more numerous and are scattered over the stem of the process, with connections to the lateral tubercles; Trilasma hidalgo sp. n. has fewer dorsal tubercles which are arrayed in a line and only rarely connected to the lateral tubercles.

Etymology.

The species epithet is a noun in apposition, referring to the Mexican state of Hidalgo.

Description.

Male holotype: total length, 3.2, width, 1.3. Color dark brown, nearly black. 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-third as long as median hood process. Circumocular keels strongly developed, subocular portion especially prominent. Median hood process arising dorsally on eye tubercle, widest point past midline of length, length 1.0, width 0.4; median keels of carapace continuing as rows of lateral tubercles on median hood process, about 30 lateral tubercles, linearly connected; about 15 dorsal tubercles present, connected in a single row to one another but not to lateral tubercles. Metapeltidium free, complete keel along anterior margin, 8 tubercles posterior to keel, connected to it by single branch each. Scute 1.3 long, 1.3 wide. All keels well elevated above dorsum. Small keel cells present on areas 2-5; area 2 with 5 or 6 small cells in single transverse row; area 3 with 10 to 12 small cells in single transverse row, but row is slightly wider than row on area 2; area 4 with two paramedian groups of 2 or 3 small cells each; area 5 similar, but only 1 or 2 small cells. Paired median scute spines prominent, significantly larger than adjacent keel tubercles on areas 2-5 (Fig. 51).

Chelicerae (Fig. 18) with basal article 0.82 long, 0.28 wide, sparsely setose; second article 0.65 long, 0.22 wide. Palpus (Fig. 27) stout, tibia, patella crassate, with dense vestiture of clavate setae; trochanter with two prominent seta-bearing ventral tubercles; dimensions given in Table 10. Legs in order of length, 2 (7.44), 4 (5.70), 3 (4.01), 1 (3.98); no false articulations; tarsi 1-4 with 4, 5, 5, 6 articles respectively. Lengths of leg segments given in Table 10. Length/width ratios of femora, in order: 4.58, 12.50. 4.58, 8.0. Leg femora with typical ornamentation.

Genital operculum broadly rounded, not separated from sternite by suture. Penis typical of genus (Figs 40, 41).

Notes.

"El Chico" doubtless refers to what is now Parque Nacional El Chico, located north of the city of Pachuca. The Parque is extensive but approximate coordinates are 20°12'26N; 98°43'52W; elevations within the park range from 2300-3090 m (7540 –10131’) asl. The mountains are covered with a dense pine forest, with fir at the higher elevations. Goodnight and Goodnight (1945b) reported Trilasma bolivari from three separate collections at this place; those specimens (AMNH, not re-examined for this study) are undoubtedly hidalgo.