Trilasma tempestado, 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 : 28-30

Trilasma tempestado sp. n. Figs 14, 1523, 2436, 3744, 4548

Types.

Holotype female and male paratype (TMM) from Cueva de Polvo Tempestado, 1-2 km south of San Josecito, Nuevo Léon, México, collected 1 March 1989 by George Veni and Allan Cobb; female paratype (TMM) from Sótano de las Tres Ventanas, Purifacición area, Cuauhtémoc, Nuevo Léon, México, collected 29 November 1981 by Paul Fambro; male paratype (TMM) from Pozo de las Pantaletas, Santa Marta de Arriba, 20 km southeast of Zaragoza (UTM 433010/2656459), collected 26 November 1999 by Peter Sprouse. See Notes, below, for a detailed discussion of these localities.

Diagnosis.

A long-legged, pale species most similar to Trilasma petersprousei sp. n., which is about half again as large. Trilasma tempestado sp. n.has the second femur about the same length as the scute, and has two false articulations in the fourth femora of both males and females, while petersprousei sp. n. lacks femoral false articulations. With the male paratype only 2.1 mm in length, this species is the smallest known Trilasma , about the same size as Martensolasma jocheni , the smallest known ortholasmatine.

Etymology.

The species epithet is a noun in apposition, referring to the type locality.

Description.

Female holotype: total length, 2.6, width, 1.5. 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-third or less as long as median hood process. Circumocular keels suppressed, but subocular portion visible, eyes relatively small. Median hood process arising dorsally on eye tubercle, with nearly parallel sides, then converging distally, widest at about midlength, length 0.90, width 0.40; median keels of carapace continuing as rows of lateral tubercles on median hood process, about 20 lateral tubercles, linearly connected; 11-12 dorsal tubercles present, connected complexly to one another and to lateral tubercles. Metapeltidium free, complete keel along anterior margin, 4 tubercles posterior to keel, connected to it by single branch each. Scute 1.6 long, 1.5 wide. All keels relatively high. Small keel cells present on areas 1-5; area 1 with 3-4 small cells in midline, area 2 with about 10 small cells in transverse row less than ½ width of scute, area 3 with about 16 small cells in midline, area 4 with 20-23 small cells in transverse row about 2/3 width of scute, area 5 with two paramedian groups of 3-4 small cells. Paired median scute spines relatively prominent, on all areas distinctly larger than adjacent keel tubercles (Figs 44, 45).

Chelicerae (Fig. 14) with basal article 0.60 long, 0.20 wide, sparsely setose; second article 0.56 long, 0.18 wide. Palpus (Fig. 24) slender, with dense vestiture of clavate setae; trochanter with two prominent seta-bearing ventral tubercles; dimensions given in Table 6. Legs in order of length, 2 (8.80), 4 (6.12), 3 (4.48), 1 (4.32); metatarsus 2 with 3 false articulations, femora 4 with 3 false articulations; tarsi 1-4 with 5, 6, 7, 8 articles respectively. Lengths of leg segments given in Table 6. Length/width ratios of femora, in order: 7.33, 16.67, 8.0, 12.14. Leg femora with typical ornamentation.

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

Male paratype: total length, 2.1, width, 1.3. Color uniform light chestnut brown. Nonsexual characters as in female (see Figs 44, 45, 48 and description, above), but dorsal ornament somewhat reduced; median hood process 0.70 long, 0.25 wide. Scute 1.3 long, 1.3 wide. Chelicera (Fig. 15) without gland on basal article, second article with strong, anteriodorsal, slightly hooked, conical protuberance, basal article 0.50 long, 0.17 wide; distal article 0.52 long, 0.16 wide. Palpal patellae and tibiae swollen, epigamic glands present and marked by patches of fine setae (Fig. 23), dimensions of palpus given in Table 7. Legs in order of length, 2 (8.68), 4 (6.00), 3 (4.48), 1 (4.26); metatarsus 2 with 2 false articulations, femur 4 with 3 false articulations; tarsi 1-4 with 5, 5, 6, 6 articles respectively. Lengths of leg segments given in Table 7. Length/width ratios of femora, in order: 7.43, 20.0, 6.89, 10.5. Genital operculum broadly rounded, marginate, with two small, lateral notches. Penis typical (Figs 36, 37).

Notes.

Like Trilasma petersprousei sp. n., this species is pale and long-legged, yet does not appear to be a troglobiont. It occurs in at least two distinct karst areas. Cueva de Polvo Tempestado is located 1-2 km south of the village of San Josecito (23°58'12.68N; 99°54'21.18W, elev. ca. 2300m (7570')). This is a small, vertical cave, one of several in the area. Sótano de las Tres Ventanas is a pit in the well-known Río Purificación karst region located in Nuevo Léon and Tamaulipas between Zaragoza, NL, and Ciudad Victoria, Tamps. The coordinates are 23°53'30.583N; 99°28'20.445W, at an elevation of 2210 m asl. The entrance pit drops 35 m to a rubble pile, which slopes down to a plug at -45 meters. Temperature measured at this point was 8.6° C during exploration on 29 November 1981 (P. Sprouse, pers. comm.) Sistema Purificación, located in this area, is one of the deepest and longest cave systems in México. Pozo de las Pantaletas is located near the village of Santa Marta at coordinates of 23°51'40.16N; 99°41'23.982W and an elevation of 2800 m asl. This is a vertical cave with multiple rope drops leading to a depth of 140 m. All of these records are rather tightly clustered in a mountainous region of Nuevo Léon that makes an easterly salient into Tamaulipas 35-45 km northwest of Ciudad Victoria. It would be no surprise to see specimens from the adjoining part of Tamaulipas.