Rhampsinitus conjunctidens, Taylor, Christopher K., 2017

Taylor, Christopher K., 2017, Notes on Phalangiidae (Arachnida: Opiliones) of southern Africa with description of new species and comments on within-species variation, Zootaxa 4272 (2), pp. 236-250 : 241-243

Rhampsinitus conjunctidens n. sp.

Fig. 2 .

Etymology. Species name noun in apposition, from the Latin conjunctus, joined together, and dens, tooth, in reference to the conjoined teeth at the base of the first cheliceral segment of larger males.

Holoype. SOUTH AFRICA: Male, on Magoebaskloof Trail, 8.6 km from Magoebaskloof Hotel , 28 km SSW Tzaneen, Limpopo, ca. 23°50'S 29°59'E, el. 1800 m, in forest, 22-23.xi.1996, C. E. Griswold ( CAS).

Paratypes (all CAS). 12 major males, 7 minor males, 4 females, 18 juveniles, as for holotype; 5 major males, 1 minor male, Magoebaskloof Hotel , 30 km SSW Tzaneen, Limpopo, ca. 23°53’S 30°00’E, el. 1800 m, in forest, 22–23.xi.1996, C. E. Griswold.

Description. Major male (figs 2a–g). Body ovate; length 4.58–6.51. Carapace width 3.21–3.82, with scattered denticles including single median denticle on anterior margin; longitudinal row of three denticles on either side anterior and lateral to eyemound; clusters of denticles at anterior corners; and transverse rows of denticles across mesopeltidium and metapeltidium. Eyemound with three or four pairs of large denticles. Opisthosomal surface granulate; tergites with transverse rows of denticles; posteriormost tergites with minute setae only. Venter mostly unarmed, with black setae; setae on coxa I raised on nodules. Chelicerae (fig. 2c) of moderate length, robust, length of first segment 2.57–4.30, second segment 4.15–6.57; first segment with numerous large denticles dorsally and ventrally, largely unarmed laterally, ventrolateral denticles may be fused basally in groups of three, particularly proximally; second segment with few scattered denticles proximodorsally, granulate ventrally and in anterior half dorsally, largely smooth in posterior half except for scattered black setae. Pedipalp (fig. 2d) length of femur 2.84– 3.82, patella 1.01–1.20, tibia 1.40–1.84, tarsus 3.16–3.90; cluster of prominent bristle-bearing nodules on pedipalpal coxa directly below insertion of trochanter; numerous denticles dorsally and ventrally on trochanter and femur; remaining segments largely unarmed (isolated denticles may be present on tibia); patella without distinct apophysis; numerous black setae present along entire length of pedipalp, plumose setae absent; microtrichia present on distal half of tarsus only. Legs long, BLI 2.02–2.50, with denticles on anterior and posterior faces of trochanters, longitudinal rows of denticles on femora; leg I with dense ventral longitudinal rows of denticles from patella to base of tarsus; leg III with sparse ventral longitudinal row of denticles on tibia; remaining leg segments unarmed except ventral pairs of spine-like setae at distal margins of metatarsal and tarsal pseudosegments; femora and tibiae with pseudosegments absent. Length of femur I 7.15–8.23, femur II 11.66–13.26, femur III 6.09–7.67, femur IV 8.69–10.16. Penis (figs 2e–h) with hatchet-shaped glans, distal profile acute, point of reflexion of posterior margin in lateral view close to midpoint, slightly proximal; shaft flattened, broadening slightly towards distal end to form moderate ‘spoon’ with weakly sclerotised margins, base moderately bulbous.

Minor male (figs 2i –j) as for major, except: Body length 4.30–5.82; carapace width 2.65–2.99. Chelicerae short, length of first segment 1.02–.86, second segment 2.24–3.00; first segment lightly denticulate dorsally and ventrolaterally; second segment unarmed with scattered black setae. Pedipalp length of femur 1.72–2.22, patella 0.75–0.85, tibia 1.05–1.23, tarsus 2.11–2.69; femur with few scattered denticles, particularly ventrally, otherwise unarmed. Legs I with ventral denticle rows extending to end of tibia only, sparse distally. Length of femur I 6.09– 7.29, femur II 10.41–11.91, femur III 5.9 2–6.61, femur IV 7.96–9.24.

Female (fig. 2k) as for major male, except: Body length 5.38–7.75; carapace width 2.89–3.45. Overall appearance lighter, less sclerotised. Chelicerae short; both segments unarmed. Pedipalp length of femur 1.49–1.75, patella 0.57–.72, tibia 0.88–1.09, tarsus 1.91–2.19; femur with numerous denticles ventrally only; patella with prominent distomedial swelling but no true apophysis; microtrichia present along entire length of tibia and tarsus. Legs with longitudinal rows of denticles on femora; leg I with sparse rows of denticles on patella and sparse ventral row of denticles on tibia; remaining segments unarmed. Length of femur I 5.97–6.45, femur II 11.36–11.78, femur III 5.95–6.20, femur IV 7.98–8.95

Comments. Rhampsinitus conjunctidens is similar in genital morphology to R. leighi Pocock 1903 , but examination of specimens of the latter from the vicinity of the type locality of Durban ( Pocock 1903; see Methods section for specimen details), confirm their status as separate species. The penis of R leighi has the distal ‘spoon’ of the shaft broader and more distinct, but narrowing to a more acute terminus (fig. 9 in Staręga 2009). It also has relatively longer spines on the eyemound, with each spine longer than the height of the eyemound alone (vs shorter in R. conjunctidens ). The second segment of the chelicerae is more evenly denticulate in major males of R. leighi , and the pedipalpal femur is much less extensively armed with only a few small denticles at the base of the femur.

One of the two males of R. leighi collected at Jackson’s Fall represents a minor male, with the chelicerae not rising above the level of the carapace, and with the second segment largely unarmed except for a few denticles on the anterior face proximally. This specimen retains elongate spines on the eyemound as in the major male. In external appearance this specimen approaches R. minor Loman 1898 , whose type locality is very close to Durban and which may prove to be synonymous with R. leighi (in which case the name R. minor would take priority). Specimens from the Soutpansberg mountain range assigned to R. leighi by Schönhofer (2008) are figured therein as having a penis morphology more similar to that of R. conjunctidens , and their identity warrants reinvestigation. Also similar in genital morphology is R. forsteri Kauri (1961) from the Royal Natal National Park; this species also differs from R. conjunctidens in having the pedipalpal femur unarmed.

Major males of R. conjunctidens can be distinguished from most other Rhampsinitus species by their denticulate pedipalps, together with their cheliceral armature of well-developed denticles retrolaterally on the first segment and largely unarmed second segment. Among other species with denticulate pedipalps, R. telifrons Pocock 1903 has a very large, forward-pointing median denticle on the anterior margin of the carapace, and five pairs of denticles on the eyemound. Rhampsinitus vittatus Lawrence 1931 is an overall more gracile species with a relatively shorter pedipalp (femur less than half total body length vs more than half in R. conjunctidens ), usually no denticles on carapace directly anterior to eyemound other than the median anterior marginal denticle, and a relatively shorter and more inflated second cheliceral segment. Rhampsinitus capensis ( Loman 1898) , R. tenebrosus Lawrence 1938 , R. fissidens Lawrence 1933 and R. hewittius (Roewer 1956) have leg I unarmed beyond the femur. Rhampsinitus tenebrosus Lawrence 1938 and R. nubicolus Lawrence 1963 have the pedipalps much longer, with the pedipalpal femur length close to or exceeding the length of the body, and R. nubicolus differs in genital morphology (the genital morphology of R. tenebrosus is unknown).

Minor males are identified as this species by their genital morphology and collection in association with major males. The pedipalpal femur remains denticulate as in major males, corroborating this species’ distinction from R. forsteri (which is probably likewise based on a minor male).

Figures

FIGURE 2. Rhampsinitus conjunctidens n. sp. A – H: holotype; I – J: minor male; K: female. A: body, male, dorsal view; B: body, male, lateral view; C: left chelicera, major male, lateral view; D: left pedipalp, major male, lateral view; E: penis, left lateral view; F: glans, left lateral view; G: glans, left lateral view, interpretative diagram; H: penis, dorsal view; I: left chelicera, minor male, lateral view; J: left pedipalp, minor male, lateral view; K: female, dorsal view.