Medmassa torta, Jin & Zhang & Zhang, 2019

Jin, Chi, Zhang, Hongli & Zhang, Feng, 2019, First records of the corinnid genera Allomedmassa Dankittipakul & Singtripop, 2014 and Medmassa Simon, 1887 from China, with the description of a new genus (Araneae: Corinnidae), Zootaxa 4585 (3), pp. 459-477 : 469-476

Medmassa torta sp. nov. (Ɵflđ) Figs 8 , 9

Type material. Holotype: ♂, CHINA: Hainan Province: Changjiang County, Bawangling Mountain, Donger Management Station (19°05.8410′N, 109°10.7814′E), 1005 m a.s.l., 50 May 2011, leg. Caikun Sun.

Etymology. The specific name is a Latin adjective meaning "twisted", referring to the twisted ventral branch of the retrolateral tibial apophysis of the male palp.

Diagnosis. The male of the new species resembles Medmassa insignis ( Thorell, 1890) in having a relatively long and distinctly bifurcated RTA, and short, spine-like embolus, but can be distinguished from it by: 1) ventral branch of RTA twisted ( Figs 8F , 9B ), whereas it is not in M. insignis ( Deeleman-Reinhold 2001: fig. 534); 2) apical part of cymbium short ( Figs 8F , 9B ), whereas it is extended and long in M. insignis ( Deeleman-Reinhold 2001: fig. 534); 3) chelicerae with three retromarginal teeth, whereas with four in M. insignis . Female unknown.

Description. Male ( Figs 8 , 9 ). Holotype: body 6.42 long; carapace 2.94 long, 2.75 wide, width/length = 0.94; abdomen 3.48 long, 2.15 wide. Carapace dark brown, smooth, almost round and flat, strong arched caput, sloping gradually back from fovea; posterior margin truncated. AME largest, AER procurved in frontal view, PER procurved in dorsal view. Diameters of eyes: AME 0.15, ALE 0.13, PME 0.14, PLE 0.13. Eye interdistances: AME–AME 0.08, AME–ALE 0.01, ALE–ALE 0.43, PME–PME 0.17, PME–PLE 0.15, PLE–PLE 0.72, ALE– PLE 0.08. OAW 0.87, CRW 1.57, OAW/CRW = 0.55. CRW/carapace width = 0.57. MOA 0.36 long, front width 0.36, back width 0.44. Clypeus height 0.30, 2 times AME diameter. Chilum present, single and triangular. Chelicerae dark brown, without concave depression at distal end dorsally; promargin and retromargin both with three teeth. Labium 0.41 long, 0.53 wide. Sternum wider than long: 1.41 long, 1.52 wide. Legs dark brown and strong, with light coxae. Measurements of legs: I 7.57 (2.14 + 1.02 + 1.90 + 1.67 + 0.84), II 7.48 (2.21 + 0.97 + 1.79 + 1.71 + 0.80), III 7.03 (2.24 + 0.97 + 1.74 + 2.08 + 1.00), IV 9.41 (2.63 + 0.96 + 2.04 + 2.68 + 1.10). Leg formula: 4123. Leg spination: femora I–II pl 2 do 3, III–IV pl 3 do 3 rl 3; patellae I–II spineless, III–IV rl 1, all with 1 proximal and 1 distal dorsal tr; tibiae I plv 7 rlv 6, II plv 6 rlv 5, III–IV pl 2 rl 2 plv 2 rlv 2 vt 2; metatarsi I–II plv 2 rlv 2, III pld 2 rld 1 plv 2 rlv 2 vt 3, IV pld 2 rld 2 plv 2 rlv 2 vt 3 dt 2. Palpal spination: femora pl 1 do 2 vt 5; patellae pl 2 do 1; tibiae pl 3; tarsi pl 1. Abdomen elongate-oval, light grey, with purple tinge; dorsal scutum dark brown, narrow and shorter than half abdominal length; no patterns posteriorly; muscular impressions distinct; epigastric sclerite weak, without post-epigastric sclerite, ventral sclerite and inframamillary sclerite absent.

Palp as illustrated ( Figs 8 E–H, 9). Tibia cylindrical, longer than wide; prolateral tubercle triangular; RTA long, twisted and bifurcated, located near distal end of tibia. Cymbium elongate-oval, dorsally with chemosensory patch; cymbium with deep furrow ventrally, extending to tip. Tegulum long, oval; sperm duct thick, U-shaped. Subtegulum exposed prolaterally. Embolus short, almost straight, spine-like, directed retrolaterally.

Distribution. China (Hainan) ( Fig. 12 ).

Paramedmassa gen. nov. (拟介蛛属)

Type species: Allomedmassa day Dankittipakul & Singtripop, 2014 .

Etymology. The generic name is a combination of the prefix Para-, indicating sub-equal, and the suffix from Medmassa , to which this genus is related. Gender feminine.

Diagnosis. Paramedmassa gen. nov. resembles the genus Medmassa in both possessing more than four pairs of ventral spines on the anterior tibiae, male palpal RTA bifurcated and the absence of morphological adaptations to ant-mimicking, but can be distinguished from it by: 1) carapace oval, obviously convex ( Figs 10A, D ), whereas it is almost around and flattened in Medmassa ( Figs 8A, D ); 2) AER straight in frontal view ( Fig. 10D ), whereas it is obviously procurved in Medmassa ( Fig. 8D ); 3) sperm duct S-shaped ( Fig. 10F ), whereas it is U-shaped in Medmassa ( Figs 8F , 9B ); 4) the ventral furrow of the cymbium closed off distally ( Fig. 10F ), whereas it continues to be open to the distal end of the cymbium in Medmassa ( Figs 8E, F ); 5) female genitalia with greatly enlarged COs, convoluted CDs and tubular spermathecae ( Figs 11E, F ), whereas with small COs, simple CDs and large round spermathecae in Medmassa ( Deeleman-Reinhold 2001: figs 553, 554; Haddad & Bosselaers 2010: figs 8– 11).

Paramedmassa gen. nov. resembles the genus Allomedmassa in general habitus, both with an oval black convex carapace and similar body colouration, but can be distinguished from it by: 1) tibia I with 5–10 pairs of ventral spines, whereas with four pairs of ventral spines in Allomedmassa ; 2) male chelicerae not concave at distal end dorsally ( Fig. 10D ), whereas a concave depression is present in Allomedmassa ( Figs 2D , 3D , 5D ); 3) male palpal tibia cylindrical, longer than wide, without bristles ( Figs 10 E–H), whereas it is wider than long and its ventral surface is distinctly elevated, and with numerous bristles in Allomedmassa ( Figs 2 E–G, 3E–G, 5E–G); 4) RTA located near the distal end of the tibia, blunt and bifurcated ( Figs 10 F–H), whereas it is located basally, is sharply pointed and not bifurcated in Allomedmassa ( Figs 2G , 3G , 5G ); 5) female genitalia with complex COs and convoluted internal duct structures ( Figs 11E, F ), whereas they are simple in Allomedmassa ( Figs 6 E–G; Dankittipakul & Singtripop 2014: figs 18, 19).

Description. Medium-sized spiders (7–10 mm), stout, non-ant-mimicking. Carapace black, oval ( Fig. 10D ), obviously convex, with rough surface, highest before fovea; widest at coxae II and III, gradually narrowing backwards in male, while wedge-shaped behind in female; strongly concave at posterior margin in male ( Fig. 10A ), while almost truncated at posterior margin in female ( Fig. 11A ); cephalic region short, with slanting lateral edges; radial and cervical grooves indistinct; fovea longitudinal, deep. AER straight in frontal view ( Figs 10D , 11D ), PER procurved in dorsal view ( Figs 10C , 11C ); AME largest, ALE and PME subequal in size and smallest. MOA length <posterior width <anterior width. Clypeus height larger than diameter of AME. Chilum present, single, triangular, sclerotized and brown ( Fig. 11D ). Chelicerae same colour as carapace, without concave depression at distal end dorsally; promargin with three, retromargin with four teeth. Endites dark brown, longer than wide; outside end obviously protruding in male ( Fig. 11B ). Labium dark brown, longer than wide in male, wider than long in female. Sternum brown, shield-shaped, longer than wide, precoxal triangles and intercoxal sclerites present. Legs reddishbrown, stout; anterior tibiae with 5–10 pairs of ventral spines; metatarsi III–IV ventrally with distal preening brush. Leg formula: 4123 in male, 1423 in female. Abdomen of male oval, pale grey, with developed anterior dorsal scutum and several blackish-grey W-shaped chevron patterns posteriorly ( Fig. 10A ); abdomen of female elongateoval, black, without dorsal scutum, with several light-coloured chevrons posteriorly in female ( Fig. 11A ); epigastric sclerite developed in female, post-epigastric sclerite, ventral sclerite absent in both sexes, inframamillary sclerite present in female ( Figs 10B , 11B ).

Male palpal tibia cylindrical ( Figs 10 E–H), longer than wide, with one triangular prolateral tubercle; RTA cylindrical, thick, blunt and bifurcated, located near distal end of tibia. Cymbium elongate, dorsally without chemosensory patch. Tegulum elongate-oval, basal and apical width nearly equal, with no other structures on tegulum except embolus; sperm duct thick, S-shaped. Embolus short, curved, sharply pointed, tip directed distally.

Epigynal region heavily sclerotized ( Figs 11 E–F). Copulatory openings situated anteriorly, greatly enlarged, with complex sclerotized margins, anterior margin fused together; these margins seem to constitute an S-shaped channel before entering copulatory ducts. Vulva: copulatory ducts long, running parallel backward, then bending and extending laterally before entering spermathecae, anteriorly thick, inner wall threaded, posteriorly slender; accessory glands digitiform, located at anterior part of copulatory ducts; spermathecae small, clavate, situated posterolaterally, far away from each other; fertilization ducts short.

Composition. Known only from the type species.

Distribution. Northern Thailand, southern Laos and southwest China.

Paramedmassa day ( Dankittipakul & Singtripop, 2014) comb. nov. (Ẍ 拟介蛛) Figs 10 , 11

Allomedmassa day Dankittipakul & Singtripop 2014: 21 , figs 7–8, 13–14, 20–25.

Material examined. CHINA: Yunnan Province: 1♂, Chuxiong City, Ailao Mountain National Nature Reserve (23°58.159′N, 101°30.666′E), 2092 m a.s.l., 18 May 2011, leg. Zongxu Li.

Other material examined. LAOS: Pakse City : 2♀ near the E-Tu Waterfall (15°11.5938′N, 106°06.1224′E), 910 m a.s.l., 15 November 2012, leg. Feng Zhang and Chao Zhang.

Diagnosis. See the generic diagnosis above.

Description. Male from China ( Fig. 10 ): body 9.19 long; carapace 4.87 long, 3.84 wide, width/length = 0.79; abdomen 4.32 long, 2.99 wide. Diameters of eyes: AME 0.33, ALE 0.23, PME 0.23, PLE 0.25. Eye interdistances: AME–AME 0.19, AME–ALE 0.10, ALE–ALE 0.97, PME–PME 0.30, PME–PLE 0.25, PLE–PLE 1.29, ALE– PLE 0.17. OAW 1.58, CRW 2.46, OAW/CRW = 0.64. CRW/carapace width = 0.64. MOA 0.58 long, front width 0.81, back width 0.76. Clypeus height 0.40, 1.21 times AME diameter. Chelicerae with three promarginal teeth, four retromarginal teeth. Labium 0.81 long, 0.67 wide. Sternum 2.27 long, 2.20 wide. Measurements of legs: I 15.92 (4.49 + 1.73 + 3.97 + 3.47 + 2.26), II 15.27 (4.35 + 1.67 + 3.65 + 3.36 + 2.24), III 12.24 (3.51 + 1.39 + 2.77 + 2.92 + 1.65), IV 16.23 (4.23 + 1.55 + 3.59 + 4.04 + 2.79). Leg formula: 4123. Leg spination: femora I–II pl 1 do 2, III pl 1 do 3, IV do 3; tibiae I plv 5 rlv 5, II plv 4 rlv 4, III pl 1 plv 2 rlv 1, IV pl 1 rl 2 plv 2 rlv 1; metatarsi I–II plv 2 rlv 2, III pl 1 plv 2 rlv 2 vt 2 (plvt 1 mvt 1), IV pl 1 rl 1 plv 1 rlv 2 vt 2 (plvt 1 mvt 1).

Females from Laos ( Fig. 11 ): Total length 9.06–10.13 (n=2), one female body 9.06 long; carapace 4.25 long, 2.91 wide, width/length = 0.68; abdomen 4.81 long, 3.02 wide. Diameters of eyes: AME 0.25, ALE 0.20, PME 0.19, PLE 0.22. Eye interdistances: AME–AME 0.17, AME–ALE 0.11, ALE–ALE 0.80, PME–PME 0.23, PME– PLE 0.27, PLE–PLE 1.11, ALE–PLE 0.16. OAW 1.35, CRW 1.84, OAW/CRW = 0.73. CRW/carapace width = 0.63. MOA 0.62 long, front width 0.65, back width 0.57. Clypeus height 0.43, 1.72 times of AME diameter. Chelicerae with three promarginal teeth, four retromarginal teeth. Labium 0.53 long, 0.64 wide. Sternum 2.01 long, 1.64 wide. Measurements of legs: I 13.03 (3.72 + 1.31 + 3.53 + 2.84 + 1.63), II 11.42 (3.28 + 1.22 + 2.88 + 2.50 + 1.54), III 9.23 (2.61 + 1.04 + 2.07 + 2.31 + 1.20), IV 12.69 (3.56 + 1.21 + 3.24 + 3.38 + 1.30). Leg formula: 1423. Leg spination: femora I pl 2 do 2, II do 2, III–IV do 3; tibiae I plv 9 rlv 9, II plv 9 rlv 8, III pl 2 rl 2 plv 2 rlv 2, IV pl 2 rl 2 plv 2; metatarsi I–II plv 2 rlv 2, III pl 1 rl 1 plv 2 rlv 2 vt 3, IV pl 1 rl 2 plv 2 rlv 2 vt 3.

Male palp ( Figs 10 E–H) and female genitalia ( Figs 11 E–F) as in the generic description.

Distribution. China (Yunnan), Laos (Pakse), Thailand (Loei, Nakhon Ratchasima, Chiang Mai) ( Fig. 12 ).

Remarks. The number of ventral spines on tibia I in the same species is variable: the male specimen from China is five, the female specimen from Laos is nine, the original description of both sexes from Thailand is 10. This is unusual and may be due to geographical reasons. Based on the one male ( China) and two female ( Laos) specimens examined here, these specimens may not be conspecific: the shape of the carapace of the two sexes varies greatly; the colouration and pattern of the abdomen are different; and how does such a simple male embolus correspond to such complex female copulatory openings and ducts? Answering these questions requires collecting more specimens and further study.

Figures

FIGURE 2. Allomedmassa mae Dankittipakul & Singtripop, 2014, male: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. left palp, prolateral view; F. same, ventral view; G. same, retrolateral view. Scale bars: 2 mm (A–B); 1 mm (D); 0.5 mm (C, E–G).

FIGURE 3. Allomedmassa bifurca sp. nov., male: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. left palp, prolateral view; F. same, ventral view; G. same, retrolateral view. Scale bars: 2 mm (A–B); 1 mm (D); 0.5 mm (C, E–G).

FIGURE 5. Allomedmassa crassa sp. nov., male: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. left palp, prolateral view; F. same, ventral view; G. same, retrolateral view. Scale bars: 2 mm (A–B); 1 mm (D); 0.5 mm (C, E–G).

FIGURE 6. Allomedmassa matertera sp. nov., female: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. epigyne, ventral view; F. same, cleared in potassium hydroxide; G. vulva, dorsal view. Scale bars: 2 mm (A–B); 1 mm (D); 0.5 mm (C, E–G).

FIGURE 8. Medmassa torta sp. nov., male: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. left palp, prolateral view; F. same, ventral view; G. same, retrolateral view; H. same, dorsal view. Abbreviations: CP—chemosensory patch. Scale bars: 2 mm (A–B); 0.2 mm (C); 0.5 mm (D, E–H).

FIGURE 9. Medmassa torta sp. nov., male: A. left palp, prolateral view; B. same, ventral view; C. same, retrolateral view. Abbreviations: CP—chemosensory patch; E—embolus; PTT—prolateral tibial tubercle; RTA—retrolateral tibial apophysis. Scale bars: 1 mm (A–C).

FIGURE 10. Paramedmassa day comb. nov., male: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. left palp, prolateral view; F. same, ventral view; G. same, retrolateral view; H. same, dorsal view. Scale bars: 2 mm (A–B); 1 mm (D); 0.5 mm (C, E–H).

FIGURE 11. Paramedmassa day comb. nov., female: A. habitus, dorsal view; B. same, ventral view; C. ocular area, dorsal view; D. cephalothorax, frontal view; E. epigyne, ventral view; F. epigyne, frontal view; G. vulva, dorsal view. Abbreviations: CD—copulatory duct; AG—accessory gland; S—spermatheca. Scale bars: 2 mm (A–B); 0.5 mm (D); 0.2 mm (C, E–H).

FIGURE 12. Distribution of species mentioned in this paper.