Megalopsalis eremiotis, Taylor, 2011

Taylor, Christopher K., 2011, Revision of the genus Megalopsalis (Arachnida: Opiliones: Phalangioidea) in Australia and New Zealand and implications for phalangioid classification 2773, Zootaxa 2773 (1), pp. 1-65 : 37-39

Megalopsalis eremiotis new species

( Figs 37 , 58–64 )

Material examined. Male holotype. Little Desert , Victoria, Australia, 36°35'S 141°45'E, 14–20 July 1974, Biology Society Trip, pitfall trap ( QM S15450 ; measured) .

Paratypes. 1 male, 1 female, Lerderderg River , Victoria, 37°34'S 144°24'E, 16 July 1996, V. W. Framenau, riparian gravel bank ( WAM; measured) ; 1 male, 1 female, Little Desert , Victoria, 36°35'S 141°45'E, 14–20 July 1974, Biology Society ( V. Salanitri, collector), pitfall trap ( QM S15447 ; measured) ; 4 males, Second Valley , South Australia, 35°32'S 138°14'E, 1–2 August 1992, J. M. Waldock ( WAM T 72869; 3 measured) .

Diagnosis. Megalopsalis eremiotis is most similar to M. serritarsus , and can only be certainly distinguished by examination of the spiracle which has more slender spines together with more elongate but less extensive lace tubercles. However, the two species can also be potentially distinguished by the presence of ventral spines on the pedipalpal femur (sometimes present in M. eremiotis , never present in M. serritarsus ) and their disjunct distributions. Megalopsalis eremiotis can be distinguished from M. leptekes and M. hoggi by the presence of dorsoventral bulges on the pseudosegments of distitarsus II, from M. pilliga by the distinctly denticulate femur II, and from M. epizephyros by the absence of dorsal spines on the pedipalpal femur.

Description. MALE (N = 6). Prosoma length 1.45–1.80, width 2.18–2.75; entire body length 3.68–4.10. Propeltidium orange-white with orange patches; entire propeltidium spinose. Ocularium iridescent white, with numerous spines. Mesopeltidium, metapeltidium and opisthosoma with broad iridescent white to purple median stripe with or without silver border, laterally mottled iridescent orange-white and yellow-orange with yellow-orange punctures. Mouthparts cream; coxae mottled yellow and iridescent white. Venter of opisthosoma mottled iridescent white.

Chelicerae. Segment I 3.56–4.83, segment II 4.78–6.19. Long, slender; cream with light brown patches on segment II. Both segments evenly denticulate. Cheliceral fingers long; mobile finger angular crescent-shaped (fig. 60).

Pedipalps (figs 61–62). Femur 1.60–2.10, patella 0.78–1.04, tibia 1.00–1.19, tarsus 1.92–2.39. White with yellow patches on patella and tibia; unarmed or with few widely-spaced ventral spines on femur. Trochanter with few dorsodistal spines. Rounded apophysis on patella about third length of patella body (fig. 62). Patella and tibia densely setose on median side. Microtrichia over distal half of tarsus; claw with ventral tooth-row.

Legs. Leg I femur 3.42–4.45, patella 0.99–1.28, tibia 2.80–3.66; leg II femur 5.35–7.12, patella 1.24–1.63, tibia 5.10–6.54; leg III femur 2.66–4.13, patella 0.94–1.22, tibia 2.17–3.01; leg IV femur 4.83–6.69, patella 1.07–1.41, tibia 3.34–4.55. Trochanters yellow medially, white laterally; trochanters I and II with denticles on prolateral face, III and IV unarmed. Femora patched golden white and yellow; patellae and tibiae golden white with yellow spots; tarsi golden white. Femur I densely spinose ventrally, with slightly longer proventral spine row, and additional spine row dorsally; patella with long ventral and short dorsal spine rows; tibia with ventral spine row along entire length and small dorsal spine row along proximal half. Femur II with ventral spine row along entire length and smaller dorsal spine along proximal three-quarters, extra anterior spines in proximal half. Tibia II faintly divided into four pseudosegments; tarsus II with ventrodistal bulges on proximal segments. Femur III with widely-spaced anterior spine row for entire length, short ventral spine row for distal fifth; remaining leg segments unarmed. Tibia IV undivided; tarsi III and IV proximally broadened, with double ventral rows of brush-like setae.

Penis (figs 63–64). Posterior bristle groups elongate; glans dorsoventrally flattened distally. Pores deeply recessed.

Spiracle (fig. 37). Anterior spines slender, extending only partway across spiracle; spines reticulate laterally, becoming less so medially; terminations simple or only minimally palmate; lace tubercles elongate.

FEMALE (fig. 59; N = 2). Prosoma length 1.06–1.13, width 2.15; entire body length 3.72–5.38. Anterior part of propeltidium light tan shaded with silver-white, with two light brown stripes between anterior margin and ocularium; remainder of propeltidium and lateral shelves light tan with light brown patches. Ocularium light tan. Mesopeltidium, metapeltidium and opisthosoma with broad silver-white median striped shaded with purple; lateral parts yellow-tan patterned with light brown. Mouthparts white-cream; coxae white-tan with median purple patches. Genital operculum white-cream with median stripe of dusted medium brown; venter of opisthosoma light brown with transverse rows of white-cream patches across segments.

Chelicerae. Segment I 0.76–0.79, segment II 1.65–1.74. White-cream with light brown patches; unarmed.

Pedipalps. Femur 1.55–1.77, patella 0.85–0.94, tibia 0.99–1.09, tarsus 1.94–2.10. Femur, patella and tibia white-cream, banded with medium brown and with longitudinal medium brown dorsal stripe on patella and tibia; tarsus white-cream. Patella with short rounded apophysis about one-third length of main body of patella; apophysis cream with medium brown tip.

Legs. Leg I femur 2.49–2.83, patella 0.81–1.01, tibia 2.26–2.55; leg II femur 4.40–4.93, patella 1.08–1.24, tibia 4.20–4.60; leg III femur 2.27–2.58, patella 0.76–0.94, tibia 1.78–2.00; leg IV femur 3.94–4.63, patella 0.98–1.06, tibia 2.75–3.19. White-cream with light brown bands and patches; unarmed. Tibia II with four pseudosegments; tibia IV undivided.

Variation. Ventral spines are present on the pedipalpal femur of the holotype and of the male South Australian specimens ( WAM T 72869). Because of the geographical overlap between specimens with and without such spines, I do not regard them as belonging to distinct species. There is also variation between specimens in the colour of the median opisthosomal stripe from iridescent white in the holotype to purple with a distinct silver border to the stripe in the WAM specimen from the Lerderberg River in Victoria. This difference in coloration may be original, or it may represent post mortem bleaching .

Etymology. Feminine diminutive of the Greek eremites, “dweller of the desert”, after the name of the type locality; noun in apposition.

Figures

FIGURES 35–38. Spiracles of Megalopsalis species. 35. Megalopsalis serritarsus, entire spiracle. 36. Same, close-up of lateral corner. 37. Megalopsalis eremiotis, close-up of lateral corner. 38. Megalopsalis epizephyros, close-up of lateral corner.

FIGURES 58–64. Megalopsalis eremiotis new species. 58. Male, dorsal view (QM S15450). 59. Female, dorsal view (WAM, Lerderderg River). 60. Male right cheliceral fingers, dorsal view (QM S15450). 61. Male left pedipalp, retrolateral view (QM S15450). 62. Patella and tibia of male left pedipalp, dorsal view (QM S15450). 63. Penis, ventral view (QM S15450). 64. Glans, lateral view (QM S15450). Scale bars for figs 58–59, 61 = 1 mm; figs 60, 62–63 = 0.5 mm; fig. 64 = 0.1 mm.