Redescription of the type species of Diaphorocellus Simon , 1893 ( Araneae , Palpimanidae , Chediminae )

The type species of Diaphorocellus Simon, 1893, the South African D. biplagiatus Simon, 1893, is redescribed, and the male is described for the first time. The species is diagnosed and figured in detail, including the copulatory organs of both sexes, previously undescribed for any species of the genus. New distributional data of D. biplagiatus are provided.


Redescription of the type species of Diaphorocellus
Simon, 1893 (Araneae, Palpimanidae, Chediminae) Introduction Diaphorocellus Simon, 1893 is a small genus of palpimanid spiders with four species distributed in the Afrotropical region (Platnick 2014, World Spider Catalog 2016).The genus has a complex and contradictory history.Simon (1893a,b) described the South African genus Diaphorocellus, and separately, D. biplagiatus Simon, 1893 (which was noted as the type species in the former study, but described only in the latter one) in two different publications.Both descriptions were based, as indicated by Simon (1893b: 315), on a single female.The genus was placed in Chedimae (=Chediminae Simon, 1893b).Soon after the description, Diaphorocellus was synonymised by Simon (1895) with Otiothops MacLeay, 1839, a genus currently known exclusively from the Neotropical region (cf.Platnick 2014).Later, Simon (1903) removed Diaphorocellus from synonymy with Otiothops and considered it a synonym of another Neotropical genus, Iheringia Keyserling, 1891.Platnick (1975) revalidated Diaphorocellus and "transferred" it to the Chediminae, although this genus has been already placed in the Chedimeae by Simon, since its description.
While resurrecting Diaphorocellus, Platnick (1975) did not mention any African species except the generotype.Meanwhile, two of them, D. helveolus (Simon, 1910) and D. rufus (Tullgren, 1910), were not previously considered in Diaphorocellus.Types of these species were not studied by Platnick, and new combinations were not suggested or indicated in his paper.In fact, both latter species were transferred to Diaphorocellus by Platnick (2000) without any formal indication of this transfer.
All genera in Chediminae were diagnosed by Simon (1893b) chiefly on the basis of eye sizes and interdistances.Besides eye pattern (large PMEs are subequal to AMEs and touch each other), D. biplagiatus differs from other genera and species of Palpimanidae by the presence of two light dorsal spots on the dark grey abdomen (Figs 1,(3)(4).Since the description of the type species, only one species has been described in the genus, D. albooculatus Lawrence, 1927 from Namibia, based on three subadult males.This species has an abdominal pattern like that of D. biplagiatus.
Although Simon (1893a) stated that he described the female of D. biplagiatus, judging from the size (4.5 mm) the holotype should be a juvenile specimen.By contrast, syntypes of D. albooculatus are 8 mm and thought to be subadult males (as indicated by Lawrence 1927).
A male, recorded (but not described) by Lawrence (1936) as belonging to D. biplagiatus, was collected from Gemsbok Pan, North West Province, South Africa, near the Botswana border.This area is distant from the Cape (historically the area around Cape Town, modern Western Cape Province), but is very close to Kang, Botswana, the type locality of D. helveolus.Most likely, this male and also two females recorded by Lawrence (1936) for the neighbouring Tsortsoga Pan actually belong to the latter species.
It is notable that none of the species considered currently to be in the genus have illustrations of the endogyne or the male palp.Additionally, we were unable to find a detailed description of the very complex endogyne for any member of the subfamily.The existing more or less detailed figures given in Jézéquel (1964) lack any indication and description of the particular structures.Two papers by Platnick et al. (1999) and Piacentini et al. (2013) provide detail figures of the female copulatory organs with indication names of different strictures, but all illustrated species belong to different subfamily, Otiothopinae, and fine structures visible through dissecting microscope on high magnification like grape-shaped gland with cilia, fine threads, or pore fields are missing.
To revise the genus, we studied numerous specimens from South Africa and adjacent states identified as D. biplagiatus.Although specimens from all over the country and adjacent Botswana have the same abdominal pattern and size, we recognised that specimens from the Western Cape clearly differ from specimens from Botswana and the eastern provinces of South Africa by the palp and the endogyne.We consider specimens from the Western Cape Province to be D. biplagiatus, and those from other areas to be D. helveolus.

Material and methods
Specimens from the following spider collections were studied: MRAC Royal Museum for Central Africa, Tervuren, Belgium; NCA National Collection of Arachnida, ARC-Plant Protection Research Institute, Pretoria, South Africa.
We examined over 40 specimens of D. biplagiatus and over a hundred specimens belonging to other species of Diaphorocellus.Although the number of specimens belonging to D. biplagiatus are high, they were collected in three localities only.In the "material examined" we list only selected samples containing males and females or samples from the exactly same locality collected in different dates.
Photographs were taken using a Zeiss Discovery V20 stereomicroscope with a Canon PowerShot G9 camera and an Olympus SZX16 stereomicroscope with an Olympus E-520 camera and prepared using CombineZP software.Scanning electron micrographs were made using the SEM JEOL JSM-5200 scanning microscope at the Zoological Museum, University of Turku, Finland.Illustrations of scuta and endogynes were made after maceration in a 20% potassium hydroxide aqueous solution and exposure for a few minutes in an alcohol/water solution of Chlorazol Black.Endogynes were photographed on slides either with an Olympus SZX16 or an Olympus BH-2.Small pieces of cotton were used to fix the copulatory organs in the correct position.Measurements were made to an accuracy of 0.01 mm.Lengths of leg and palp segments were measured on the dorsal side, from the midpoint of the anterior margin to the midpoint of the posterior margin.All measurements are given in millimetres.Notes.Since its description, the genus has always been considered a member of the Old World subfamily Chediminae Simon, 1893.Diaphorocellus can be easily recognised by the large PME that are very close or even touching each other (as in Fig. 8).Only Otiothops MacLeay, 1839, a representative of the New World subfamily Otiothopinae Platnick, 1975, has similarly shaped and arranged PMEs (Grismado and Ramírez 2002: fig. 2;Buckup and Ott 2004: fig. 1;Grismado 2008: fig.1).However, Diaphorocellus differs from this genus by the presence of the accessory structures on the male palp accompanying the embolus  that are characteristic of the Chediminae but absent in the Otiothopinae (see Platnick 1975;Platnick et al. 1999).The genus includes four poorly known species recorded from Botswana, Namibia, South Africa and Tanzania (Platnick 2014;World Spider Catalog 2016).None of these species have been reconsidered since their original descriptions and no illustrations of the endogyne or the male palp have been provided until now.Diagnosis.The species can be distinguished from D. albooculatus by eye arrangement: in D. biplagiatus, the distance between the AMEs is two times less than their diameter, whereas in D. albooculatus, the distance is subequal; the shape of the ventral scuta of the males also differs (cf.Fig. 7 and Lawrence 1936: fig.54).D. helveolus can be distinguished from D. biplagiatus by the abdomen lacking long whitish hairs (vs.an abdomen covered with long whitish hairs in the latter).Diaphorocellus biplagiatus can be distinguished from D. rufus by the abdominal colouration (bicolorous in the former species vs. uniformly dark in the latter), as well as by the shape of the ventral scuta in females (cf.Fig. 2 and Tullgren 1910: fig.29).
Habitus: as in Figs 2, 3. Measurements: TL 5.47, CL 2.83, CW 1.48.Colour in alcohol: as in male, but leg I coloured similarly to legs II-IV (but not darker, contrary to that of male).Carapace: longer, with less coarse granulations than in male (Fig. 6).

Figures 20- 26 .
Figures 20-26.Details of endogyne of Diaphorocellus biplagiatus.20 dorsal 21 basal part, caudal-dorsal 22 grape-shaped glands 23 base of receptacles, dorsal 24 tip of base showing cilia 25 lateral part of receptacle base showing grape-shaped glands and fine threads 26 terminal part of receptacle base 21-26 made by transmitting microscope.Abbreviations: Cg cilia of Gg; Da dark area of Sb; Ft fine threads; Gg grapeshaped gland; Rs membranous sac like part of Re; Sb complex sclerotised base of Re.

Figure 27 .
Figure 27.Distribution of Diaphorocellus biplagiatus.The type locality (open circle) and new records listed in the text (solid circles).