Afroceto africana ( Simon, 1910 ) Haddad, 2019

Haddad, Charles R., 2019, Transfer of the Namibian Argistes africanus Simon, 1910 (Araneae: Liocranidae) to Afroceto Lyle & Haddad, 2010 (Trachelidae), with a new synonym, Zootaxa 4571 (3), pp. 446-450 : 447-449

Afroceto africana ( Simon, 1910) comb. nov.

Figs 1–8

Argistes africanus Simon, 1910: 201 [subadult ♀ holotype: NAMIBIA: Lüderitzbucht, leg. Schultze, ZMB 27144—examined]. Afroceto arca Lyle & Haddad, 2010: 339 , figs 3, 4, 43–49 (♀ ♂), syn. nov.

Remarks. Although both the original description of Argistes africanus ( Simon 1910) and the eighth publication in the series on the Arachnida types in ZMB ( Moritz & Fischer 1988) indicated that the type specimen is a female, detailed examination showed that it is, in fact, a subadult female without a developed epigyne ( Figs 1–3 ). The type shares a number of characters with the trachelid Afroceto arca ( Figs 4–6 ), which is the only representative of the genus that has been recorded from Namibia to date ( Lyle & Haddad 2010; Lyle 2015; World Spider Catalog 2018). It, together with the type species A. martini (Simon, 1897) and A. plana Lyle & Haddad, 2010 , are the only three of the 16 described Afroceto that have been recorded outside of South Africa and the enclave of Lesotho.

Despite its poor condition, the type of Argistes africanus shows traces of a branched chevron marking dorsally on the abdomen, a feature unique to Afroceto arca and A. corcula Lyle & Haddad, 2010 amongst members of that genus (see Lyle & Haddad 2010: figs 1–22). The general carapace shape, proportions and eye arrangement of the two species are also similar (compare Figs 2 and 5 ), as are the proportions of the ovoid abdomen and general structure of the spinnerets (compare Figs 3 and 6 ). The characteristic ventral markings of A. arca ( Fig. 6 ) are not evident in the faded holotype of Argistes africanus ( Fig. 3 ), nor did Simon (1910) mention them in the original description, only describing the dorsal and lateral markings and indicating the venter as “clay-coloured”: “ Abdomen longe oblongum, superne cinereo testaceum, maculis nigris triseriatis, medianis subtriquetris, lateralibus longis et obliquis, ornatum, subtus albo-testaceum.”

The only known record of Afroceto from Namibia to date ( Lyle & Haddad 2010) is a single male specimen from Vogelfederberg [23°03'S, 14°59'E], which is approximately 400 km north of Lüderitzbucht [modern Lüderitz, 26°38'S, 15°09'E], the type locality of Argistes africanus ( Fig. 9 ). The two localities are separated by the Namib Desert, one of the most hostile places on earth, but to the east of this desert are relatively arid but more hospitable Nama Karoo and Savanna habitats. Considering the widespread distribution of Afroceto arca in South Africa, including the latter two vegetation types ( Lyle & Haddad 2010), it is likely that the two species are conspecific. Argistes africanus is hereby transferred to Afroceto as A. africana ( Simon, 1910) comb. nov., and proposed as a senior synonym of A. arca syn. nov..

Description. See Lyle & Haddad (2010) for description of both sexes.

Diagnosis. Afroceto africana comb. nov. is a typical member of the genus, which is characterized from other Afrotropical Trachelidae by their relatively large size, the presence of several strong prolateral spines on the anterior femora, a dorsal scutum in males (usually absent in females), and the presence of many long ventral cusps on the anterior legs of males (and sometimes females too, but not including A. africana comb. nov.; see Lyle & Haddad 2010). The genus has a shield-shaped sternum and slightly bulging chelicerae ( Fig. 7 ), as do most Afrotropical trachelids. Afroceto africana comb. nov. can be easily recognized from congeners by the distinct shape of the epigyne, with a broad, anteriorly arched, strongly sclerotised atrium that has a generalized keyhole shape ( Fig. 8 ), and the males with a short, distally coiled embolus (see Lyle & Haddad 2010: figs 46–49).

New records. SOUTH AFRICA: Eastern Cape: Nearly 7 km S of Hogsback on R345, isolated tree, roadside, 32°38.831'S, 26°55.375'E, 715 m a.s.l., 1.×.2011, leg. J. Neethling & C. Luwes (canopy fogging), 1♂ 1♀ ( NCA 2012 /1641) . Free State: Brandfort district, Amanzi Private Game Reserve, 28°35.428'S, 26°26.067'E, 1425 m a.s.l., 17.XII.2016, leg. C. Haddad (hand collecting around buildings), 2♂ ( NCA 2016 /3036); Brandfort district , Krugersdrift Dam , 28°42'S, 25°55'E, 1.I.1987, leg. Museum staff (in canal), 1♀ ( NMBA 9057 ) ; Fauresmith district, Farm Boschrand, 29°56'S, 24°48'E, 22.III.2005, leg. L. Lotz (sweeping, beating), 1♀ ( NMBA 10 007); Luckhoff district , Farm Bankfontein , 30°04.421'S, 24°53.017'E, 22.I.2015, leg. C. Haddad (hand collecting, Nama Karoo veld), 2♀ ( NCA 2015 /1669); Same locality, 2.IV.2015, leg. University of the Free State students (sifting leaf litter, riparian woodland), 1♀ ( NCA 2015 /2442); Kalkfontein Dam Nature Reserve, 29°31.285'S, 25°16.662'E, 15.I.2014, leg. Y. Marusik (sifting leaf litter), 2♂ ( NCA 2014 /1069); Same locality, 29°31.072'S, 25°16.091'E, 28.I.2014, leg. N. Josling (in garden amongst plants), 6♂ 1♀ ( NCA 2015 /1910); Same locality, 29°31.071'S, 25°16.069'E, 6.II.2014, leg. N. Josling (amongst flowers in garden), 1♂ ( NCA 2015 /1981); Same locality, 29°31.072'S, 25°16.091'E, 12.XI.2013, leg. N. Josling (in wasp nest), 1♀ ( NCA 2015 /1993) . Western Cape: Jacobsbaai , 34°21.430'S, 19°07.557'E, 8.V.2010, leg. C. Haddad (on wall of house at night), 1♀ ( TMSA 23787 ) ; Matjiesfontein , 33°13.783'S, 20°34.818'E, 900 m a.s.l., 15.X.2015, leg. Z. Mbo (sifting leaf litter), 1♀ ( NCA 2016 / 2363) .

Distribution. Afroceto africana is widespread in the more mesic Grassland, Nama Karoo and Fynbos habitats of southern Africa, with only a few sporadic records from the moister eastern parts of South Africa ( Fig. 9 ). All of the new records reported here fall within the known distribution range of the species.

Figures

FIGURE 9. Distribution of Afroceto africana (Simon, 1910) comb. nov.: black star = type locality of Argistes africanus Simon, 1910; open circles = published records of Afroceto arca Lyle & Haddad, 2010 syn. nov. (from Lyle & Haddad 2010); open triangles = new records.

FIGURES 1–6. Morphology of Afroceto africana (Simon, 1910) comb. nov.: 1–3. Holotype subadult female of Argistes africanus Simon, 1910; 4–6. Female of Afroceto arca Lyle & Haddad, 2010 syn. nov.: 1, 4. Habitus, dorsal view; 2, 5. Carapace, dorsal view; 3, 6. Abdomen, ventral view. Scale bars: 1 mm.

FIGURES 7–8. Morphology of Afroceto africana (Simon, 1910) comb. nov. female: 7. Sternum and mouthparts; 8. Epigyne, ventral view. Scale bars: 0.5 mm.