Izithunzi silvicola, (PURCELL, 1904), 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 : 421-424

IZITHUNZI SILVICOLA ( PURCELL, 1904) COMB. NOV.

( FIGS 3D–F, 4D, 5, 7, 8–11, 21, 22)

Drymusa silvicola Purcell, 1904: 152 , pl. 11, figs 24, 25 [♀] [♂, 2♀ and three immature syntypes ( SAMC 871 ) from South Africa, Western Cape Province, Knysna , [− 34.035086, 23.046469], March 1896, W. Purcell col., not examined].

Remarks: Whereas we have not examined the syntypes of this species, the key, description and illustrations provided by Purcell (1904: 152–154) and the examination of topotypes leave no doubt as to the species identity.

Material examined: 4♀ and eight immatures from South Africa, Western Cape Province, Knysna , [− 34.033333, 23.033333], October 1946, Malkin col., preparation codes APG-00002 [♀] and APG-00063 [♀], CAS ( CASENT9021765 ) ; two immatures, same locality, Industrial Area , [− 34.044894, 23.077147]), 3 February 1991, collected in big tree, V . Roth col., CAS ( CASENT9048598 ) ; 2♂ and 2♀, same province, Harkerville State Forest , 19 km E Knysna, −34.05, 23.233333, 11–13 December 1996, elev. 240 m, C. Griswold col., indigenous forest, preparation codes FML-00548-00549 [♂] and FML-00558 [♀], deposited in CAS ( CASENT9021766 ) ; 2♂, 3♀ and 11 immatures, same data, CAS ( CASENT9048601 ) ; ♂, same data, preparation codes FML-01008- 01009 and FML-01117, CAS ( CASENT9048600 ) ; ♀, same data, CAS ( CASENT 9053369 ) ; ♀, same data, CAS ( CASENT9053371 ) ; ♀, same data, CAS ( CASENT 9053372 ) ; ♂, same data, CAS ( CASENT 9053367 ) ; ♂, same data, CAS ( CASENT9053370 ) ; one immature, same data, CAS ( CASENT 9053368 ) ; one immature, same data, CAS ( CASENT9053374 ) ; ten immature, same data, CAS ( CASENT9048601 ) ; 2♀ and two immatures, same data, CAS ( CASENT9021766 ) ; ♀ and two immatures, same data, forest, hand collecting, night, P. Sierwald col., FMNH ; 5♀, same province, Kranshoek , 20 km E Knysna, −34.0833, 23.2333, 13 December 1996, elev. 180 m, indigenous forest, C. Griswold col., CAS ( CASENT9021764 ) ; ♀, same data, forest, hand collecting, night, P. Sierwald col., FMNH ; ♀, same province, Diepwalle Forest Station , 22 km NE Knysna, −33.948599, 23.157369, 10–13 January 1985, elev. 1800 ft., indigenous forest in holes in tree trucks, C. Griswold, T . Meikle Griswold cols., preparation codes FML-01002- 01007 and FML-01011-01012, CAS ( CASENT9048599 ) ; ♂, 5♀ and three immatures, same data, 11–13 November 1985, indigenous forest, C. Griswold, J. Doyen, T . Meikle Griswold cols., NMSA ; ♀, same data, NMSA ; 4♀ and two immatures, same data, 10–13 November 1985, in holes tree trunks in indigenous forest, C. Griswold, T . Meikle Griswold cols., NMSA ; ♀ and two immatures, same data, 11–13 December 1996, elev. 540 m, C. Griswold col., CAS ( CASENT9021761 ) ; three immatures, Eastern Cape Province, Tsitsikamma National Park , 78 km E Knysna, −34.023483, 23.890333, 17–18 February 2006, elev. 15 m, coastal forest, J. Miller, H. Wood cols., CAS ( CASENT9023643 ) .

Diagnosis: Females of I. silvicola comb. nov. resemble those of I. productum comb. nov. by the inner and outer spermathecae clustered, and the integrated plate ( Figs 10, 18, 19, 21), but can be distinguished by the epigastrium and postepigastrium plates, the dorsal receptaculum with muscle insertions and partially integrated to the (posterior) plate and the anterior ridge diffuse ( Figs 4D, 21), while I. productum comb. nov. lacks both epigastrium and postepigastrium plates, has an integrated dorsal receptaculum without muscle insertions and conspicuous anterior ridge ( Figs 18, 19). Males of I. silvicola comb. nov. can be distinguished from other Izithunzi by the pedipalp elongated, the ventral condyle of the patella-tibiae joint not projecting prolaterally, cymbium swollen (L ≤ 1.5× W) and 1.5 times longer than the base of the copulatory bulb, and the apex more than three times longer than the base ( Fig. 21).

Redescription female (Harkerville State Forest: Habitus CASENT 9021766; SEM CASENT 9043066; Measurements CASENT 9053369): Total length 8.8. Prosoma: length 3.49, width 2.67, height 2.18. Sternum: length 1.76, width 1.45. Leg measurements: femur: I: 9.8, II: 8.0, III: 6.74, IV: 8.72; patella: I: 0.82, II: 0.93, III: 0.92, IV: 0.97; tibia: I 9.44, II: 7.12, III: 5.85, IV: 8.4; metatarsus: I: 9.36, II: 7.6, III: 5.61, IV: 8.24; tarsus: I: 1.54, II: 1.48, III: 1.46, IV: 1.92; podotarsite: I: 0.12, II: 0.15, III: 0.14, IV: 0.14; total: I: 31.08, II: 25.28, III: 20.72, IV: 28.39. Leg formula: 1423. Opisthosoma: length 5.25, width 2.42, height 2.95. Chelicerae promargin with six bracket setae ( Fig. 3D), and a row of seven macrosetae against the triangular lamina. Cheliceral retromargin with an extra small tooth, next to the apical tooth on the cheliceral furrow. Labium dun, reddish at narrow area and white at apex ( Figs 8, 22). Pedipalpal prolateral femoral thorn thick, distally blunt ( Fig. 3F). Sternum dun ( Fig. 22). Femora and tibiae dun, patellae, metatarsi and tarsi tan ( Fig. 22). Opisthosoma colour overall dark brown, smooth, without chevrons ( Fig. 22). Epigastrium plate extending posteriorly beyond middle of opisthosoma, covered with thin setae ( Fig. 21). Postepigastrium plate triangular, swollen, just below the epigastric furrow ( Fig. 21). Lateral sclerotized grooves conspicuous, well defined, associated with the postepigastrium plate ( Fig. 21). Inner spermathecae oval. Outer spermathecae tetrahedral ( Fig. 21). Inner spermathecae duct opening to the integrated plate anteriorly, next to the outer spermathecae ( Fig. 21).

Redescription male (Harkerville State Forest: Habitus CASENT 9021766; SEM and leg measurements CASENT 9048600; Body measurements CASENT 9053367): Total length 5.93. Prosoma: length 2.73, width 1.98, height 1.39. Sternum: length 1.48, width 1.2. Leg measurements: femur: I: 11.7, II: 9.7, III: 7.6, IV: 9.8; patella: I: 0.86, II: 0.89, III: 0.83, IV: 0.92; tibia: I 11.5, II: 9.12, III: 6.92, IV: 9.3; metatarsus: I: 12.65, II: 9.9, III: 7.6, IV: 9.9; tarsus: I: 1.67, II: 1.6, III: 1.59, IV: 2.2; podotarsite: I: 0.14, II: 0.12, III: 0.19, IV: 0.16; total: I: 38.52, II: 31.33, III: 24.73, IV: 32.28. Leg formula: 1423. Opisthosoma: length 3.3, width 1.43, height 1.31. Male pedipalp: femur: 2.02, patella: 0.69, tibia: 1.04, tarsus: 0.47. Coloration lighter than in female, thoracic area pattern reduced, V-shaped mark narrower ( Fig. 21D–F). Epiandrous spigots arising in three bunches from isolated pits. Pedipalpal prolateral femoral thorn distally acute and longer than in females; femora elongated (L> 4× W); tibiae thin (L> 2.5× W) ( Fig. 21). Copulatory bulb apex elongated ( Fig. 21). In addition, the copulatory bulb apex appears slightly curved in lateral (both pro- and prolateral) and apical views ( Fig. 21).

Distribution: Western and Eastern Cape Provinces, South Africa, in Knysna-Amatola montane forests ( Fig. 5; Supporting Information, Fig. S1).