Rhampsinitus leighi Pocock 1902
Creators: name: Starêga, Wojciech
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Phalangiidae
Rhampsinitus
Rhampsinitus leighi

description: Rhampsinitus leighi (Pocock, 1902)
Figs 6–11
Phalangium (Rhampsinitus) leighi Pocock, 1902: 396, fig. 80 (type locality: Durban).
Rhampsinitus leighi: Roewer 1911: 92; Roewer 1912: 161, figs 12, 29; Roewer 1923: 791; Lawrence 1931: 497; Lawrence 1933: 240, figs 33–37; Lawrence 1938: 370; Roewer 1950: 50; Roewer 1956: 309; Kauri 1961: 159, figs 91–92; Staręga 1984: 63.
Material examined. Republic of South Africa: „Transkei, District Lusikisiki, côte embouchure riv. Mzimhlava, forêt”, 51 ɗ, 26 Ψ (MRAC 152.530: 46 ɗ, 23 Ψ + RCWS II/0040: 5 ɗ, 3 Ψ) collected in December 1979 by M.E. Baddeley. Transkei coast, Lusikisiki District, Mzimhlava river mouth, coastal evergreen forest, 21 ɗ, 7 Ψ (MRAC 163.148), 1 Ψ, 1 juvenile (MRAC 163.151) (December 1979), 6 ɗ (MRAC 159.026), 2 ɗ, 1 Ψ (MRAC 163.221), 1 Ψ (MRAC 166.783), 1 subad. ɗ (MRAC 166.804) (January 1980), 4 ɗ, 3 Ψ (MRAC 163.975), 1 ɗ (MRAC 166.671) (February 1980) all collected by M.E. Baddeley. 3 ɗ (MRAC 166.524), 1 ɗ (MRAC 166.573) from Transkei coast, Port St Johns, collected in November 1980 by M. Baddeley. 1 ɗ, 5 Ψ (MRAC 166.744) from Transkei coast, Ntafufu river, Lusikisiki district, collected in February/ March 1980 by M. Baddeley. 2 juveniles (MRAC 171.691) from Natal, Howick, Umgeni Valley spider reserve, by hand, dense vegetation near river, collected 18 July 1990 by M. Alderweireldt and R. Jocqué.
Diagnosis. The species is externally easily recognizable by its shape, coloration, enormous chelicerae and very long legs. There are also specific differences in genital morphology (see Kauri 1961: 148–150, 159–162).
Description. MALE: body slightly flattened dorsally, 5.1–9.0 mm long. Carapace 3.1–4.6 mm wide, with two longitudinal rows of sharp denticles in front of eye mound. Similar denticles in groups in front and hind corners of carapace and scattered singly between eye mound and lateral margins. Eye mound nearly as high as long, with „crown” of 3+3 long, pointed thorns; its distance from frontal margin slightly longer than its length. Each tergite (the „thoracal” and all abdominal) with single transversal row of large, pointed denticles. Venter smooth, several small denticles in basal part of coxa I only.
Chelicerae of varying shape and length, from small (2.4 mm + 3.6 mm) similar to those in females (Fig. 7) to very long (Fig. 6), length of each segment exceeding body length (11.5 mm + 12.3 mm; in one case even 13.0 mm) [all specimens in the same sample!]. Basichelicerite covered with sharp denticles and granules, only laterally smooth. Second segment very densely covered with sharp granules, a smooth longitudinal area medially, between chelae and about ¾ of length. Pedipalps (Fig. 8) in contrast to chelicerae not varying, short, slen- der and nearly unarmed, with few small denticles ventrally on trochanter and in basal part of femur. A narrow ventral furrow (glandular or receptive?) in distal half of tarsus. Tarsus slightly bent. Length: total 9.0 mm, femur 3.61 mm, patella 1.08 mm, tibia 1.46 mm, tarsus 3,46 mm. Legs very long and strong. All segments cylindrical. Femora with regular rows of denticles. Femur I apically with a cluster of larger denticles. Patella I strongly armed with numerous denticles, the other patellae only with few small apical denticles. Tibia I clearly bent, with rows of small sharp denticles (the ventro-apical ones enlarged). Metatarsus I with sharp granules (in entire rows ventrally and in broken ones dorsally). Other tibiae and metatarsi mainly with bristles. All tarsal segments with apical bristles. Femur length: I: 9.8–14.4 mm, II: 17.8–20.4 mm, III: 9.6–12.5 mm, IV: 11.8–15.4 mm. BLI 2.190–3.696. Metatarsi with false joints: I: 3–4 (5), II: 8–10 (11), III: 3 (4), IV: 5–6 (7); equal ranges in both sexes; some asymmetric, in some cases 9 on the right and 11 on the left 2nd metatarsus of the same specimen.
Penis (Figs 9–11) slender, shaft with distinct apical „spoon”; 3.92 mm long, basis 0.54 mm wide, „spoon” 0.38 mm wide, glans 0.62 mm, stylus 0.23 mm long (in specimen from Mzmihlava; MRAC 166.671). Lateral shaft margins strongly sclerotized distally, glans thin, nearly triangular in profile.
Body coloration very dark brown, giving the living animal a black appearance. Carapace dark brown, with darker „shades”. Abdomen similar but slightly lighter; no saddle. Venter brownish, coxae dark brown. All appendages either dark brown (chelicerae) or blackish (palps, legs). Sharply contrasting, nearly white accents caused by ventral crescent-shaped membranes between coxae and trochanters and by a triangular whitish spot on hind part of eye mound continuing also on dorsal and frontal surface but here already darkening and vanishing. Penis dark yellowish, with dark brown sclerotized margins of „spoon”. Smaller specimens with weaker chelicerae and lighter coloration: on light brown (in some parts even yellowish!) background blackish brown spots on carapace and a saddle on the abdomen, saddle constricted just behind eye mound and triangularly broadening backwards. Each abdominal segment with a transverse row of large, sharp tubercles.
FEMALE: body length 6.0–9.0 mm, carapace width 3.2–5.6 mm. Dorsal body armature and coloration similar as in males. Strikingly different (well visible even in living individuals) by a white venter, strongly contrasting with very dark brown or nearly black coxae and dorsum. Some lighter specimens with yellow carapace (with dark brown patches) and sides of abdomen shaded with yellow and brown. A light brown saddle beginning at frontal margin of abdominal tergite I, sharply broadened on II, constricted again and continuing slightly broadening till hind margin of tergite V. Venter white, coxae light brown. Appendages light brown, only palpal femur and end parts of leg segments dark brown. Length of 2nd cheliceral segment about 2.5 mm. Femur length: I: 8.3–10.1 mm, II: 15.4–22.3 mm, III: 7.5–10.2 mm, IV: 11.5–14.2 mm. BLI 1.575–2.571.
Variation. Males show an enormous variability in the shape of their chelicerae: from small, slender, similar as in females (Fig. 7) to very strong, elongate, four or more times as long as the body (Fig. 6). Smaller males with smaller chelicerae have probably reached adulthood in an earlier instar. Some of them have even a lighter coloration. The females show variability in body coloration, which is probably not related to age but to their degree of sclerotization (the lighter individuals can be much bigger than the dark ones – in the same series).
Distribution. This is a very common species in KwaZulu-Natal Province (Pocock 1902, Roewer 1912, 1950, 1956, Lawrence 1931, 1933, 1938, Kauri 1961). Now a rich material is available from the Eastern Cape Province (former Transkei). In the collection of the Natal Museum (Pietermaritzburg) there are samples from further localities (all in KwaZulu-Natal): Eshowe, Hluhluhwe Game Reserve, Dhlinza Forest, Ngotsche Forest, Qudeni Forest, Impendhle, Umgeni Bush (Durban), Amanzimtoti, Port Edward, St Helier, Umgeni valley near Drummond, Pietermaritzburg, Richmond (det. R.F. Lawrence or W. Starçga). This is a typical lowland species, distributed from sea level (Durban, Amazimtoti, Port Edward, Mzimhlava mouth) inland to the vicinity of Pietermaritzburg and Richmond, and up to about 800 m altitude. It is the largest long-legged, black harvestman in KwaZulu-Natal and the adjoining part of the Eastern Cape Province. It is probably active at night and can be easily found resting on herbaceous plants, shrubs and tree trunks during the day.
description: Published as part of Starêga, Wojciech, 2009, Some southern African species of the genus Rhampsinitus Simon (Opiliones: Phalangiidae), pp. 43-56 in Zootaxa 1981 on pages 47-49, DOI: 10.5281/zenodo.185315