Megalopsalis suffugiens, Taylor, Christopher K., 2013

Taylor, Christopher K., 2013, Further revision of the genus Megalopsalis (Opiliones, Neopilionidae), with the description of seven new species, ZooKeys 328, pp. 59-117 : 69-72

Megalopsalis suffugiens sp. n. Figs 2 c–d, 5

Material examined.

Male holotype. Balgair Station, cave 6 N– 612, Western Australia, 14 September 1999, N. Poulter, from ceiling adjacent to cave entrance (WAM T72303).

Paratypes. 1 male, Balgair Station, cave 6 N– 1536, Western Australia, 13 September 1999, N. Poulter, walking on damp earth floor (WAM T72299); 1 male, ditto, c. 11 m below cave entrance (WAM T72307); 1 female, Balgair Station, cave 6N-1616, Western Australia, 15 September 1999, P. Devine, N. Poulter, rockhole cave (WAM T72287); 2 males, 1 female, Hampton Tableland, Mundrabilla Station, cave 6 N– 326, 22 September 1999, P. Devine, N. Poulter, from cave walls in dark zone, largest [female] from entrance lip at night fall (WAM T72298); 1 female, Madura Plains Station (=Moonera Station), cave 6 N– 1617, 17 September 1999, R. Anderson, N. Poulter, from cave ceiling in dark zone (WAM T72305); 1 female, Nullarbor area, cave 6 N– 481, 1 October 1994, R. Foulds, from roof of entrance squeeze (WAM T72141).

Diagnosis.

Megalopsalis suffugiens is readily distinguished from other species of the Megalopsalis minima -species group by its pale coloration without dark transverse bands on the opisthosoma (Fig. 5 a–b). The spines on the legs (if present) are also proportionately longer and more slender than those found in other species. It can also be distinguished from Megalopsalis minima by the lack of denticles on the ocularium and median propeltidial area (Fig. 5a) and from Megalopsalis porongorupensis by the lack of denticles on the pedipalps.

Description.

MALE (N = 5). Prosoma length 0.75 (0.68-0.83), width 1.69 (1.56-1.86); total body length 2.21 (2.08-2.30). Dorsal prosomal plate unarmed (Balgair Station specimens) or with few denticles on anterior propeltidial area (Hampton Tableland specimens); patched tan and iridescent white with scattered darker mottling. Mesopeltidium with distinct transverse row of black setae. Metapeltidium and anterior part of opisthosoma mottled tan and silver. Posterior part of opisthosoma silver with transverse bands of dark brown mottling.

Chelicerae. Segment I 1.47 (0.78-2.22), segment II 2.44 (1.56-3.28). Both segments tan; lightly denticulate with reduced denticulation distad on both segments. Segment II slightly inflated distad. Cheliceral fingers long, slender; mobile finger crescent-shaped.

Pedipalps. Femur 1.01 (0.87-1.09), patella 0.51 (0.50-0.54), tibia 0.57 (0.54-0.64), tarsus 1.27 (1.20-1.33). White with tan patches and black setae; femur with longitudinal rows of setae; patella and tibia with black setae laterally and medially, midline glabrous; no apophysis. Microtrichia over greater part of tarsus and tibia; claw with ventral tooth row.

Legs. Femora 3.83 (3.17-4.45), 7.14 (6.38-7.77), 3.10 (2.66-3.36), 4.94 (4.10-5.56); patellae 0.90 (0.83-0.99), 1.05 (0.98-1.12), 0.85 (0.78-0.94), 0.99 (0.90-1.06); tibiae 3.71 (3.34-4.00), 7.42 (6.81-7.89), 3.57 (2.90-4.05), 4.91 (4.10-5.52). Trochanters iridescent white; unarmed or with single anterior spine on trochanters I and III. Legs tan; femur I with sparse, slender spines, reduced to only a few dorsally in some specimens; femur II unarmed or with few spines near base; remaining segments unarmed. Femora and patellae with scattered black setae; tibiae and tarsi densely covered in small setae. Tibia II with 11 to 13 pseudosegments; tibia IV with two or three pseudosegments.

Penis (Figs 5 c–d). Shaft broad, tendon relatively short; bristle groups well-developed. Glans short, broad, triangular in dorsal view; in line with shaft; dorsal side evenly convex; not significantly flattened distally. Pores shallowly recessed.

Spiracle (Figs 2 c–d). No occluding spines; lace tubercles at lateral corner reduced to patch of reticulation.

FEMALE (N = 4). Prosoma length 1.16 (0.61-1.45), width 2.13 (1.98-2.28); total body length 3.83 (3.40-4.40). As for male, except for following: Dorsum unarmed.

Chelicerae. Segment I 0.75 (0.66-0.81), segment II 1.58 (1.55-1.62). Unarmed.

Pedipalps. Femur 1.31 (1.28-1.34), patella 0.68 (0.65-0.71), tibia 0.78 (0.73-0.83), tarsus 1.65 (1.63-1.67). Patella and tibia more densely setose medially than male.

Legs: Femora 4.68 (4.45-4.95), 9.28 (8.73-10.23), 4.01 (3.72-4.28), 5.95 (5.63-6.16); patellae 1.18 (1.07-1.24), 1.42 (1.32-1.45), 1.11 (1.03-1.19), 1.19 (1.13-1.24); tibiae 4.79 (4.65-4.96), 9.77 (9.12-10.38), 4.44 (4.28-4.63), 6.05 (5.81-6.25). Femora and patellae with longitudinal rows of small spines.

Variation.

Males show a noticeable variation in the size of the chelicerae that correlates with the development of armature on the legs; however, the variation is not as large as that found in Megalopsalis minima , and it is uncertain at present whether variation is continuous or a distinction occurs between major and minor males. Further specimens are also required to establish whether the difference in dorsal armature recorded above between Balgair Station and Hampton Tableland specimens indicate separate populations in these localities.

Etymology.

From the Latin suffugio, to take shelter, to reflect the finding of specimens of this species within caves in the arid Nullarbor.

Comments.

All specimens of Megalopsalis suffugiens recorded to date were collected in caves; however, Megalopsalis suffugiens does not show any obvious troglobitic adaptations. The eyes remain well-developed and the legs are proportionately only slightly longer than in other Megalopsalis species. It seems more likely that Megalopsalis suffugiens only uses the caves as damp refugia during the day, emerging at night to feed. This suggestion is supported by the collection of at least one specimen (WAM T72298) from a cave entrance at nightfall.