Izithunzi, Labarque & Pérez-González & Griswold, 2018

Labarque, Facundo M., Pérez-González, Abel & Griswold, Charles E., 2018, Molecular phylogeny and revision of the false violin spiders (Araneae: Drymusidae) of Africa, Zoological Journal of the Linnean Society 183, pp. 390-430 : 405

GENUS IZITHUNZI GEN. NOV.

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Type species: Drymusa capensis Simon, 1893 .

S p e c i e s i n c l u d e d: I z i t h u n z i c a p e n s e (S i m o n, 1893) comb. nov., I. lina sp. nov., I. productum ( Purcell, 1904) comb. nov., I. silvicola ( Purcell, 1904) comb. nov. and I. zondii sp. nov.

Etymology: The generic name means shadows ( Izithunzi ) in Xhosa, a South African Nguni language of Bantu People. It refers to the retiring nature and cryptic environments (i.e. hidden in caves’ crevices or under dense vegetation) where the members of this genus live. The name is neuter in gender.

Remarks: Lehtinen (1967) and Platnick et al. (1991) predicted the non-monotypy of Drymusidae . Lehtinen (1967: 301) compared the Neotropical Drymusa nubila Simon, 1892 with the South African D. capensis (= I. capense comb. nov.) and considered that they were not congeneric (although he took no formal action).

Monophyly: Putative synapomorphies include (1) cheliceral promargin with ‘rubble teeth’ that are massive, blunt and boulder shaped ( Fig. 3D); (2) female with two sclerotized plates on the vulva, anterior and posterior to the uterus externus ( Fig. 7A, B); and (3) male with anterior stridulatory ridge plate on opisthosoma ( Fig. 7C, D).

Diagnosis: Izithunzi gen. nov. can be distinguished from Drymusa by the boulder-shaped cheliceral promarginal rubble teeth, the female genitalia having two sclerotized plates anterior and posterior to the uterus externus and the male opisthosoma having an anterior stridulatory ridge plate.

Description: Female total length between 5.65 and 15.03 and male total length between 4.95 and 12.27. Carapace reddish with distinguished dun pattern forming two central large patches making a backward-pointing V-shaped mark, each anteriorly prolonged in three longitudinal lines surrounding the eyes and laterally extending in three wavy lines; clypeus with cross-linked pattern. Cephalic area slightly more than one-half width of thoracic area. Chelicerae promargin with two massive and blunt teeth, the rubble teeth, usually dark under the microscope, a triangular lamina contiguous with the paturon margin with a row of several macrosetae against it and a fleshy lobe apically blunt with a basal row of several long and filiform setae, the bracket setae ( Figs 3D, 8A). Cheliceral retromargin with two rubble teeth, rarely three (see I. silvicola comb. nov.), forming a row perpendicular to the fang furrow, apical tooth large and proximal small ( Fig. 4A). Chelicerae ectal margin stridulatory ridge formed by multiple shallow scales ( Fig. 3E). Fang venom gland outlet distal, facing anteriorly ( Fig. 3D). Cheliceral bases articulated with a small, sclerotized, posterior intercheliceral sclerite ( Fig. 8B). Venom gland extending into carapace ( Fig. 8C). Endites longer than wide, bending prolaterally and converging in front of the labium, fleshy apical profiles almost touching each other ( Fig. 8D). Labium trapezoidal, longer than wide, narrowed close to the acute apical margin and partially separated from sternum by a membranous suture ( Figs 8, 9). Maxillary gland pore field clumped ( Fig. 8). Labral tongue apically concave, with dorsal setae ( Fig. 8). Pedipalpal claw reduced to a nubbin, distal tarsus with four prolateral macrosetae curved distally, and basal femur with prolateral thorn that might be distally acute or blunt ( Fig. 3F). Sternum oval, longer than wide, bordered ( Fig. 9). Precoxal triangles fused to sternum ( Fig. 9). Legs tan dappled with dun. Proclaws I–II clearly bipectinate with longer teeth on the prolateral row; retroclaws I–II with prolateral tooth row ( Fig. 3A). Foot articulated, closed podotarsite with one subdivision, distal hood covering the base of the superior claws, with distal-ventral frictional setae ( Fig. 3A, B). Tarsal organ exposed, ovoid and with three receptor-cell dendrite terminals (sensilla) ( Fig. 9). Metatarsal trichobothria opening distal margin entire; proximal and distal plates of trichobothria smooth, not well differentiated, distal plate contiguous with the surrounding cuticle; sculpture on basal expansion of trichobothrial setae smooth ( Fig. 9). Metatarsi III– IV with dense brush of apical ventral setae ( Fig. 4B). Pedicel lorum triangular, not transversely divided, narrowed posteriorly to a pointed end, without slit sensilla stripes ( Fig. 9). Pedicel sternites and pleurites separated. Opisthosoma colour overall dark brown with or without chevrons. Epigastrium posterior border with two small, lateral, sclerotized grooves, which seemingly provide a guide for the copulatory bulb apex (see at end of paragraph) to enter into the vulva. Epigastrium and postepigastrium on the external genital area may be heavily sclerotized, forming the epigastrium plate and the postepigastrium plate, respectively (see I. silvicola comb. nov.). Postepigastric foveae absent from abdominal venter (present in many Scytodes and some Neotropical Drymusa ). Vulva with an anterior pair of spermathecae (inner), each connected to the uterus externus through a duct ( Figs 4D, 7, 10A–C), an anterior sclerotized plate with a second pair of spermathecae (outer) and a posterior sclerotized plate with two dorsal receptacula ( Figs 7, 10A–C). Inner spermatheca larger than outer, its duct may open far from (separated, Figs 10A, B) or directly next to the latter (clustered, Figs 4D, 10C). Outer spermathecae and dorsal receptaculum may provide opisthosomal muscle insertions ( Fig. 10C). Spermathecae and dorsal receptaculum with ductless glands well spaced or in patches of two to many glands ( Figs 4D, 7, 10A–C). Sclerotized plates may be separated from each other surrounding the uterus externus ( Figs 7A, 10A), pressed together anteriorly squeezing the uterus externus ( Figs 7B, 10B) or completely integrated with the uterus externus forming a unit, the integrated plate ( Figs 10). Integrated plate may present a conspicuous or diffuse anterior longitudinal middle ridge ( Fig. 10C) forming a sort of crest, which extends across the plate. Uterus externus may or may not extend beyond the vulval plate anterior borders (compare I. capense comb. nov. against I. zondii sp. nov.). Tracheal spiracle wide, separated from spinnerets ( Fig. 11). Third opisthosomal entapophyses fused, forming a long median trachea ( Fig. 3C). Colulus well defined, ovoid and posteriorly narrowed ( Fig. 11). Anterior lateral spinnerets ( ALS) with three articles ( Fig. 11). ALS with two major ampullate gland spigots (MaAm) and a separated field of several piriform (Pi) gland spigots ( Fig. 11). Posterior median spinnerets ( PMS) tetrahedral with basal straight and plumose setae on anteromedian surface, a single aciniform gland spigot (Ac), and a field of spicules on mesal surface Fig. 11. Posterior lateral spinnerets ( PLS) conical, with several aciniform gland spigots ( Fig. 11). Male markings as in female. Opisthosoma with an anterior sclerotized plate with stridulatory ridge, dorsally facing posterior prosoma ( Fig. 7). Epiandrous spigots arising in several bunches from isolated pits ( Fig. 12). Male with spinnerets as in female but differs in having the PLS with one aciniform gland spigot instead of several spigots ( Fig. 11). Male pedipalp with prolateral femoral thorns as in females ( Fig. 13). Patella-tibia joint dicondylic, ventral condyle heavily sclerotized, projecting prolaterally, arthrodial membrane broad prolaterally, occupying one third of patella ( Figs 12, 13); these modifications on the articulation seem to allow a prolateral movement to the tibia. Femora narrow (L ≤ 3.5× W) to elongated (L> 4× W). Tibiae swollen (L <2× W) to thin (L> 2.5× W) (compare I. capense comb. nov. against I. silvicola comb. nov.). Cymbium as long as wide to swollen (L ≤ 1.5× W), apically blunt, and as long as or 1.5 times longer than the copulatory bulb base (compare I. capense comb. nov. against I.silvicola comb. nov.). Copulatory bulb presenting one non-expandable piriform sclerite (subtegulum, tegulum and embolus fused). Base (subtegulum + tegulum) showing the sperm duct. Apex (embolus) as long as to more than three times longer than the base, laminated, slightly curved and implanted prolaterally (compare I. productum comb. nov. against I. silvicola comb. nov.).