Medmassa semiaurantiaca Simon, 1910

Haddad, Charles R. & Bosselaers, Jan, 2010, A revision of the genus Medmassa Simon, 1887 (Araneae: Corinnidae) in the Afrotropical Region, Zootaxa 2361, pp. 1-12 : 3-6

Medmassa semiaurantiaca Simon, 1910

( Figs 1–15 )

Medmassa semiaurantiaca Simon, 1910: 376 (Ƥ Holotype: GUINÉE-BISSAU: Guinea Portuguese, Bolama, leg. L. Fea, MNHN 18810 – examined).

Medmassa hiekae Berland, 1922: 74 , plate A4, fig. 3 (3 juvenile syntypes: ETHIOPIA: Hieka Bourka, 31.III.1904, leg. M. de Rothschild, MNHN – examined). syn. nov.

Remarks. Medmassa hiekae Berland, 1922 was described from three juveniles from Hieka Bourka in Ethiopia. This locality could not be traced, and is thus presumed to be a misspelling of Burka, east of Addis Ababa. Only one male has subsequently been collected from Ethiopia, and this specimen is M. semiaurantiaca . We thus propose the synonymy of M. hiekae with M. semiaurantiaca .

Diagnosis. This species shares with M. insignis (Thorell, 1890) and M. celebensis ( Deeleman-Reinhold, 1995) the subapical lamellar process on the RTA of the male palp ( Fig. 13 ), but can be distinguished from these two species by the longer, sharp, dorsally directed tip of the RTA. Females of M. semiaurantiaca can be recognised by the distinctive copulatory ducts in the female epigyne ( Figs 8–11 ), copulatory openings situated posterior to the anterior margins of the spermathecae, fewer cheliceral teeth, and absence of abdominal markings (see Deeleman-Reinhold 2001).

Female. Measurements: CL 2.80–3.90, CW 2.33–3.16, AL 2.85–3.68, AW 2.00–2.66, TL 5.63–7.72, FL 0.28–0.42, SL 1.40–2.00, SW 1.40–2.02. Interdistances between eyes: AME–AME 0.08, AME–ALE 0.05, ALE–ALE 0.58, PME–PME 0.21, PME–PLE 0.12, PLE–PLE 0.67.

Length of leg segments (sequence from femur to tarsus, and total): I 3.52 + 1.52 + 3.65 + 2.58 + 1.80 = 13.07; II 3.35 + 1.33 + 2.52 + 2.51 + 1.64 = 11.35; III 3.25 + 1.22 + 2.70 + 3.20 + 1.86 = 12.23; IV 4.05 + 1.40 + 3.38 + 4.18 + 1.95 = 14.96.

Carapace deep orange-brown, eye region slightly darker, slightly paler posteriorly, with dark brown mottled markings ( Fig. 1 ); carapace highest posterior to PER, at one-third its length, sloping gently towards posterior margin, with slight depression anterior to fovea; surface finely wrinkled, sparsely covered in short fine straight setae, with several longer erect setae in eye region and along carapace midline; fovea long, distinct, slightly thickened, at two-thirds carapace length. Eyes surrounded by black rings ( Fig. 7 ); AER strongly procurved, AME much larger than ALE; clypeus height slightly larger than AME diameter; AME separated by distance slightly less than one-third their diameter; AME separated from ALE by distance approximately one-eighth AME diameter ( Fig. 7 ); PER strongly procurved ( Fig. 1 ), median eyes slightly larger than laterals; PME separated by distance equal to their diameter; PME separated from PLE by distance equal to half PME diameter. Chelicerae dark brown; anterior surface with scattered short and long, fine erect setae; chilum single; promargin with three teeth, median tooth largest, distal tooth smallest, adjacent to median tooth; retromargin with three widely separated teeth, decreasing gradually in size distally. Sternum orange-brown, with slightly darker markings radiating from centre to between coxae; surface smooth, covered in long, fine setae; precoxal triangles present; intercoxal sclerites present between coxae I and II only; anterior pleural bars fused, posterior bars isolated. Abdomen uniform dark grey dorsally, with 3–4 pairs of short spines along anterior margin behind petiole ( Fig. 1 ); abdomen slightly paler grey laterally and ventrally; abdomen oval, broadest at half its length; dorsal scutum absent; surface covered in short fine straight setae; dorsum with two pairs of large weakly sclerotised sigilla, first at one-third and second at two-fifths abdomen length; venter with indistinct small oval sclerites, running in two paired lines from behind epigastric fold to spinnerets; inframamillary sclerite present. Legs I to IV with femora orange-brown, much darker in distal third; remaining leg segments uniform yellow-brown; retrocoxal hymen present on coxa I; patellar indentation narrow, approximately one-third patellar length; legs strongly spined, especially anterior tibiae and metatarsi ( Fig. 2 ); metatarsi III and IV with dense distal scopulae, tarsi weakly scopulate; remaining leg segments covered in fine, short setae. Leg spination as follows: femora: I pl 2 do 3, II pl 3 do 3, III pl 3 do 3 rl 3, IV pl 2 do 3 rl 2; patellae: spineless, all with 1 proximal and 1 distal dorsal tr; tibiae: I plv 8 rlv 6–7, II pl 2 plv 5 rlv 4, III pl 2–3 rl 2 plv 3 rlv 3 vt 2, IV pl 2 rl 2 plv 2 rlv 2 vt 2; metatarsi: I plv 2 rlv 2, II plv 2 rlv 2, III pl 1 rl 1 plv 2–3 rlv 2 vt 3, IV pl 2 rl 2 plv 2 rlv 2 vt 3; all tibiae, metatarsi and tarsi with numerous dorsal and ventral tr, increasing in size distally. Palpal spination ( Fig. 3 ): femora: pl 1 do 2 plv 1 rlv 6; patellae pl 2 do 2; tibiae pl 3 do 2 rlv 2; tarsi pl 1 plv 1 rlv 1. Epigyne with large ST I and no ST II; copulatory openings situated anteromedially within curved depression; copulatory ducts short, bent or straight, entering ST I medially ( Figs 8–11 ).

Male. Measurements: CL 2.76–3.82, CW 2.30–3.20, AL 3.15–4.10, AW 1.95–2.10, TL 6.03–7.25, FL 0.28–0.48, SL 1.45–2.00, SW 1.48–2.02. Interdistances between eyes: AME–AME 0.07, AME–ALE 0.03, ALE–ALE 0.62, PME–PME 0.19, PME–PLE 0.08, PLE–PLE 0.73.

Length of leg segments (sequence from femur to tarsus, and total): I 4.05 + 1.60 + 3.62 + 3.14 + 2.20 = 14.61; II 3.74 + 1.45 + 3.08 + 3.10 + 2.10 = 13.47; III 3.58 + 1.34 + 3.00 + 3.74 + 2.13 = 13.79; IV 4.31 + 1.41 + 3.66 + 4.91 + 2.17 = 16.46.

General habitus, colouration and abdominal spines ( Fig. 4 ), intercoxal sclerites, precoxal triangles and eye pattern ( Fig. 12 ) similar to female described above; male less robust than female, with slightly longer legs; legs similarly strongly spined ( Fig. 5 ), with small retrocoxal hymen on coxa I and narrow patellar indentation approximately one-third patellar length; abdomen with narrow elongate dorsal scutum, extending to half abdomen length ( Fig. 4 ). Leg spination as follows: femora: I pl 2 do 3, II pl 3 do 3, III pl 3 do 3 rl 2, IV pl 2 do 3 rl 2; patellae: spineless, all with 1 proximal and 1 distal dorsal tr; tibiae: I plv 7–8 rlv 6, II pl 2 plv 5 rlv 4–5, III pl 2 rl 2 plv 2 rlv 2 vt 2, IV pl 2 rl 2 plv 2 rlv 2 vt 2; metatarsi: I plv 2 rlv 2, II pl 1 plv 2–3 rlv 2–3, III pl 2 rl 2 plv 2 rlv 2 vt 3, IV pl 2 rl 2 plv 2 rlv 1 vt 3; all tibiae, metatarsi and tarsi with numerous dorsal and ventral tr, increasing in size distally. Male palp with convex RTA, attached broadly to tibia, with bifid tip comprising tooth-like subapical prolateral process and hooked retrolateral apophysis ( Figs 6 , 13, 14 ); palpal tarsus teardrop-shaped; tegulum drop-shaped with short, slightly curved distal embolus; subtegulum visible prolaterally ( Fig. 13 ). Palpal spination ( Fig. 6 ): femora: pl 1 do 2 plv 1 rlv 6; patellae pl 2 do 1; tibiae pl 2 do 1 plv 1; tarsi pl 1.

Variation. The variation in female epigynal structure in different populations of M. semiaurantiaca across the region, particularly the length of the copulatory ducts ( Figs 8–11 ), is not met with any variation in male palpal structure (embolus shape and length, RTA structure), and thus we consider all of these populations to be conspecific.

Additional material examined: BOTSWANA: Maun, Government camp house no. 36, 19°59'S, 23°25'E, XII.1976, leg. A. Russell-Smith, 13 ( MRAC 224663); Okavango Delta, Near Shakawe, Lesideng Research Camp, 18°25.822'S, 21°53.771'E, 26–29.XI.2006, leg. C. Haddad (night collecting), 4imm. 33 (NCA 2007/955); Okavango Delta, Samochima lagoon, Shakawe Fishing Camp, 18°25.749'S, 21°54.035'E, 29.XI.2006, leg. C. Haddad (under tree bark), 1Ƥ (NCA 2007/1023). CENTRAL AFRICAN REPUBLIC: Prefacture Sangha-Mbaéré, Réserve Spéciale de Forêt Dense de Dzanga-Sangha, 12.7km 326° NW Bayanga, 420m a.s.l., 03°00'18''N, 16°11'36''E, 10–17.V.2001, leg. B.L. Fisher (beating low vegetation, rainforest), 1Ƥ ( CAS BLF 4087). CONGO D.R.: Luki Biosphere Reserve, 05°37'S, 13°05'E, 4.XI.2006, leg. D. de Bakker & J.-P. Michiels (canopy fogging, primary forest), 1Ƥ ( MRAC); Same data, 26.IX.2007, 13 ( MRAC); Same data, 1.X.2007, 13 1Ƥ ( MRAC); Tshopo, Masako, 00°35'N, 25°11'E, 4.VII.2001, leg. J. Juakaly (old Hevea plantation), 1Ƥ ( MRAC 212122). ETHIOPIA: Lake Langano, Ras Hotel, 07°38'N, 38°42'E, 24.XI.1982, leg. A. Russell-Smith (under stones, in very short grass), 13 ( MRAC 224664). GHANA: Kakum forest, 05°20'N, 01°23'W, 21.XI.2005, leg. R. Jocqué, D. de Bakker & L. Baert (primary forest, fogging), 1Ƥ ( MRAC 218275); Same data, 23.XI.2005, 13 ( MRAC 218282); Same locality, 15.XI.2005, leg. R. Jocqué, D. de Bakker & L. Baert (secondary forest, fogging), 1Ƥ ( MRAC 218252); Same data, 24.XI.2005, 1Ƥ ( MRAC 218286). KENYA: Western region, Kakamega Forest, Lirhanda hills, 00°13'N, 34°54'E, 13.IV.2000, leg. D. Shilabira Smith (malaise trap), 1Ƥ ( MRAC 220499); Same data, 18.V.2002, 13 ( MRAC 220517); Same locality, 25.V.2000, leg. D. Shilabira Smith (pitfall trap), 13 ( MRAC 220491); Kakamega Forest, 00°22'N, 34°50'E, 1600m a.s.l., IX–X.2001, leg. W. Freund (fogging, Teclea nobilis , middle-aged secondary forest), 13 1Ƥ ( ZFMK Ar1155). SOUTH AFRICA: KwaZulu-Natal Province, iSimangaliso [Greater St Lucia] Wetlands Park, Gwala Gwala Forest, 28°23.042'S, 32°24.436'E, 21.IV.2006, leg. C. Haddad (leaf litter, coastal forest), 1saƤ (NCA 2008/4277); Same locality, Hell’s Gate Block B, 28°00.0'S, 32°28.8'E, leg. J. Esterhuizen (tsetse fly traps), 13 (NCA 2009/3478).

Distribution. Currently known from scattered localities throughout the Afrotropical Region, from South Africa in the south to Ethiopia in the north, and from Kenya in the east to Guinée-Bissau in the west ( Fig. 15 ).

Natural History. This is a rapidly-running nocturnally-active hunting spider that was commonly found on the bark of smooth-barked trees in riparian forest in the Okavango Delta, Botswana. Regularly collected during canopy fogging surveys in forests and savanna habitats in tropical Africa, although not an abundant species.

Figures

FIGURE 15. Distribution of Medmassa semiaurantiaca Simon, 1910 in the Afrotropical Region. Arrow indicates Guinée-Bissau locality.

FIGURES 1 – 6. Digital microscope photographs of Medmassa semiaurantiaca Simon, 1910 female (1 – 3) and male (4 – 6) male from Botswana. (1, 4) habitus, dorsal view; (2, 5) leg I tibia and metatarsus; (3, 6) pedipalp, lateral view. Abbreviations: AAS – anterior abdominal spines; EVS – erect ventral femoral spines on palp; RLS – retrolateral spines on palp. Scale bars = 1.0 mm.

FIGURES 7 – 14. Medmassa semiaurantiaca Simon, 1910: (7 – 11) female, (12 – 14) male. (7, 12) carapace, frontal view; (8 – 10) epigyne, ventral view from Ghana (8), Congo D. R. (9) and Botswana (10); (11) epigyne, dorsal view from Botswana; (13) palp, ventral view; (14) palp, retrolateral view. Scale bars = 0.1 mm.