Forsteropsalis chiltoni ( Hogg 1910 ) 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 : 48-49

Forsteropsalis chiltoni ( Hogg 1910) new combination

( Figs 92–98 )

Macropsalis chiltoni Hogg 1910: 277–278 , fig. 3— Roewer 1912: 280; Hogg 1920: 31, pl. 1, figs 1–2.

Megalopsalis chiltoni (Hogg) — Roewer 1923: 868; Forster 1944: 185–186, pl. 65, figs 7–9 (in part); Taylor 2004: fig. 3d–f.

Material examined. ( MONZ, unless otherwise specified). SI. 1 female, Freshwater Flats , Stewart Island, 46º51’S, 167º54’E, 16 May 1995; 1 male , Mason’s Bay , Stewart Island, 46º54’S, 167º48’E, 15 May 1995; 1 male, 1 female ,

3 juveniles, Bravo , Stewart Island, 23 November 1946, under logs ; 2 females, Halfmoon Bay , 22 November 1946; 8, Maori Bay, Stewart Island, 25 November 1946, ex foliage ; 1 male, Port Pegasus Camp , southern Stewart Island, 23 February 1972, ex foliage ; 1 male, 1 st bay north of Whale Passage , southern Stewart Island, 21 Feb 1972, Port Pegasus ; 1 male, southern Stewart Island, Twilight Bay littoral, Port Pegasus, 29 Feb 1972 ; 1 male, 1 st bay north of Whale Passage , Port Pegasus, southern Stewart Island, 21 February 1972, F. M. Climo ; 2 females, Stewart Island [pre-1924] ( BMNH). All localities in New Zealand .

Description. MALE (N = 2). Prosoma length 3.0–3.2, width 3.8–4.6. Prosoma mauve to medium brown with yellow U-shaped stripe around ocularium and tan interior to U-stripe; scattered denticles in front of ocularium and on anterior corners; few scattered black setae throughout; metapeltidium not sclerotised. Ocularium silver with black margins around eyes and black setae. Dorsum of opisthosoma unarmed; dark brown to mauve with lighter lateral punctures; purplish dorsal median stripe; transverse rows of white spots along segmental boundaries; white patches on lateral margins. Coxae dark brown to tan, with black setae; venter of opisthosoma dark brown to tan with white spots.

Chelicerae (figs 93–94). Segment I 7.5–10.0, segment II 10.0–13.0. Segment I tan proximally, medium brown distally; segment II medium brown; tan fingers; both segments heavily denticulate. Cheliceral fingers bowed apart proximally; mobile finger angular crescent-shaped (fig. 94).

Pedipalps (figs 95–96). Femur 2.2–2.8, patella 1.0–1.2, tibia 1.4–1.6, tarsus 3.4–4.0. White with brown stripes on femur; femur denticulate; small, pointed apophysis on patella (fig. 96). Microtrichia on distal two-thirds of tarsus; claw without ventral tooth-row.

Legs. Leg I femur 5.5–8.0, patella 1.0–1.5, tibia 5.0–7.0; leg II femur 8.8–12.0, patella 1.5–2.0, tibia 8.5–11.0; leg III femur 5.0–7.0, patella 1.0–1.5, tibia 4.5–5.0; leg IV femur 7.5–9.5, patella 1.5, tibia 6.5–8.5. Trochanters golden brown; unarmed. Legs striped tan and medium brown; femora lightly denticulate; all segments with black setae. Tibia II with five pseudosegments; tibia IV with two pseudosegments.

Penis (figs 97–98). Bristle groups well-developed. Glans in line with shaft; medium length, sides converging in ventral view; no dorsolateral keel. Pores raised on small emarginate papillae; dorsal face with large, nodular papillae.

Spiracle. Dense curtain of reticulate spines entirely covering spiracle; terminations of spines palmate; no lateral lace tubercles.

FEMALE (N = 3). Prosoma length 2.2–2.6, width 2.8–3.4. Prosoma mostly medium brown; yellow stripe on either side of ocularium to anterior margin; rest of dorsum mottled medium brown and tan; black setae throughout. Ocularium silver with black margins to eyes and two longitudinal rows of black setae. Coxae mottled dark brown and tan, with black setae; venter of opisthosoma medium brown with tan spots along segmental boundaries.

Chelicerae. Segment I 1.0–1.5, segment II 2.0–3.0. Segment I medium brown dorsally, tan ventrally; segment II medium brown proximally, tan distally; longitudinal rows of black setae on both segments.

Pedipalps. Femur 1.6–2.2, patella 0.8–1.0, tibia 1.0–1.2, tarsus 2.2–3.0. Striped medium brown and tan; femur smooth; small, pointed apophysis on patella.

Legs. Leg I femur 3.0–5.0, patella 1.0–1.5, tibia 2.8–5.0; leg II femur 5.0–8.5, patella 1.5–2.0, tibia 5.0–8.5; leg III femur 3.0–4.5, patella 1.0–1.5, tibia 2.8–4.0; leg IV femur 4.5–7.0, patella 1.3–1.5, tibia 4.0–6.0. Striped medium brown and tan, with black setae. Tibia II with four to six pseudosegments, tibia IV with two pseudosegments.

Comments. The publication date for Hogg (1910) has often been cited as ‘1909’; Crawford (1992) stated that it had not been published until 1 June 1910. The location of the holotype of F. chiltoni is unknown. It could not be located in the BMNH, which houses the types of other megalopsalidines described by Hogg (J. Beccaloni, personal communication 2001). Hogg’s (1910) species is recognisable as a Forsteropsalis from the original description, and the species described here is the only Forsteropsalis known from the type locality (Stewart Island).

Specimens assigned by Forster (1944) to this species from the region of Wellington are here re-identified as males of Forsteropsalis inconstans (see below).

Forsteropsalis chiltoni is very similar to F. marplesi , and can only be distinguished by the lower number of pseudosegments in the male tibia II, and a tendency to be darker in coloration (which may be artefactual). The number of pseudosegments may be a dubious character, and a single female specimen had six pseudosegments in tibia II on one side of the body (five pseudosegments on the other side), which overlaps with the range for F. marplesi . The two species are tentatively retained as distinct until their relationship can be further examined.

Figures

FIGURES 92–98. Forsteropsalis chiltoni (Hogg 1910), male (all MONZ, Whale Passage). 92. Body, dorsal view. 93. Left chelicera, lateral view. 94. Left cheliceral fingers, dorsal view. 95. Left pedipalp, retrolateral view. 96. Patella and tibia of right pedipalp, dorsal view. 97. Glans, ventral view. 98. Glans, lateral view. Scale bars for figs 92, 94–96 = 1 mm; fig. 93 = 2 mm; figs 97–98 = 0.2 mm.