Rhampsinitus Simon 1879

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 : 240

Rhampsinitus Simon 1879

Rhampsinitus Simon 1879 : lxxii.

Notes. Rhampsinitus Simon 1879 may be the most difficult genus of African Phalangiinae , if only because of its high diversity of recognised species. It is widespread in southern Africa with described species as far north as Angola in the western part of the continent and Somalia in the east. However, those species found in the northern part of Rhampsinitus ’ range remain unrevised and their assignment to this genus requires confirmation. Over much of the southern part of its range, Rhampsinitus is the only genus of Phalangiidae known to be present. It has been distinguished from most other African genera of Phalangiidae by its cheliceral morphology, in which the male chelicerae are enlarged and usually denticulate in comparison to the female, but not swollen as in Guruia . However, as described below for R. conjunctidens and R. nubicolus , not all males of Rhampsinitus have enlarged chelicerae and cheliceral development may vary significantly even within a single species. Rhampsinitus can be distinguished from all other Afrotropical phalangiine genera except Dacnopilio by its male genital morphology with a hatchet-shaped glans, and with the distal end of the penile shaft broadened and hollowed to form a distinct ‘spoon’. Dacnopilio was distinguished from Rhampsinitus by the presence of denticles on the supracheliceral lamellae ( Roewer 1911). Dacnopilio as currently recognised has a biogeographically unusual distribution, being the only genus of Phalangiidae with representatives in both the Afrotropical and Mediterranean regions ( Staręga 1984), and warrants further investigation.

The Rhampsinitus species of South Africa were revised by Lawrence (1931) and Kauri (1961), with the latter providing the most recent key for the identification of males. Unfortunately, subsequent studies ( Schönhofer 2008; Staręga 2009) have exposed issues with earlier revisions by demonstrating the presence of a wider range of withinspecies variation than previously recognised. It is possible that a number of species currently recognised in Rhampsinitus may prove synonymous. Kauri’s (1961) key draws heavily on characters of the chelicerae that may not prove reliable (it should also be noted that a number of species characterised within the key by ‘unarmed chelicerae’ are in fact described from females only). The genital morphology for a number of species described by earlier authors remains undescribed, further complicating comparisons. Particularly problematic on this front is the type species of the genus, R. lalandei Simon 1879 , for which the type specimen has been lost (Muñoz-Cuevas in Crawford 1992) and the type locality is uncertain (it was originally reported as ‘Cafrerie’, possibly corresponding to somewhere in what is now the Eastern Cape province) .

Of particular note is the identification below of minor males for at least two species, R. conjunctidens and R. nubicolus , with the chelicerae not enlarged and mostly unarmed. This represents a more extreme form of the variation within species described by Schönhofer (2008) for R. transvaalicus and Staręga (2009) for R. leighi . As noted by Schönhofer (2008), variation in cheliceral size also corresponds with variation in pedipalpal length, individuals with longer chelicerae also having longer pedipalps relative to body length. It is likely that other species in the genus will prove to exhibit such variation with further investigation. Kauri (1961) described two species from minor males, R. forsteri Kauri 1961 and R. qachasneki Kauri 1961 , though no corresponding major males are yet known. As described below, R. minor Loman 1898 is likely to represent a minor form of R. leighi Pocock 1903 . The identification of minor males is likely to prove problematic; those of R. conjunctidens and R. nubicolus cannot be readily distinguished except through examination of the genitalia.