Medmassa torta

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

publication ID

https://doi.org/10.11646/zootaxa.4585.3.3

publication LSID

lsid:zoobank.org:pub:1BA367F9-0A0D-4CC6-9D94-D947459723BA

persistent identifier

http://treatment.plazi.org/id/03D287C6-FF9D-7426-87B0-FA98FD9D4CB2

treatment provided by

Plazi

scientific name

Medmassa torta
status

sp. nov.

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

Type material. Holotype:GoogleMaps  ♂, CHINA: Hainan Province: Changjiang County, Bawangling Mountain, Donger Management Station   GoogleMaps (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 8FView FIGURE 8, 9BView FIGURE 9), whereas it is not in M. insignis  ( Deeleman-Reinhold 2001: fig. 534); 2) apical part of cymbium short ( Figs 8FView FIGURE 8, 9BView FIGURE 9), 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 8View FIGURE 8, 9View FIGURE 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 8View FIGURE 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. 12View FIGURE 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, DView FIGURE 10), whereas it is almost around and flattened in Medmassa  ( Figs 8A, DView FIGURE 8); 2) AER straight in frontal view ( Fig. 10DView FIGURE 10), whereas it is obviously procurved in Medmassa  ( Fig. 8DView FIGURE 8); 3) sperm duct S-shaped ( Fig. 10FView FIGURE 10), whereas it is U-shaped in Medmassa  ( Figs 8FView FIGURE 8, 9BView FIGURE 9); 4) the ventral furrow of the cymbium closed off distally ( Fig. 10FView FIGURE 10), whereas it continues to be open to the distal end of the cymbium in Medmassa  ( Figs 8E, FView FIGURE 8); 5) female genitalia with greatly enlarged COs, convoluted CDs and tubular spermathecae ( Figs 11E, FView FIGURE 11), 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. 10DView FIGURE 10), whereas a concave depression is present in Allomedmassa  ( Figs 2DView FIGURE 2, 3DView FIGURE 3, 5DView FIGURE 5); 3) male palpal tibia cylindrical, longer than wide, without bristles ( Figs 10View FIGURE 10 E–H), whereas it is wider than long and its ventral surface is distinctly elevated, and with numerous bristles in Allomedmassa  ( Figs 2View FIGURE 2 E–G, 3E–G, 5E–G); 4) RTA located near the distal end of the tibia, blunt and bifurcated ( Figs 10View FIGURE 10 F–H), whereas it is located basally, is sharply pointed and not bifurcated in Allomedmassa  ( Figs 2GView FIGURE 2, 3GView FIGURE 3, 5GView FIGURE 5); 5) female genitalia with complex COs and convoluted internal duct structures ( Figs 11E, FView FIGURE 11), whereas they are simple in Allomedmassa  ( Figs 6View FIGURE 6 E–G; Dankittipakul & Singtripop 2014: figs 18, 19).

Description. Medium-sized spiders (7–10 mm), stout, non-ant-mimicking. Carapace black, oval ( Fig. 10DView FIGURE 10), 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. 10AView FIGURE 10), while almost truncated at posterior margin in female ( Fig. 11AView FIGURE 11); cephalic region short, with slanting lateral edges; radial and cervical grooves indistinct; fovea longitudinal, deep. AER straight in frontal view ( Figs 10DView FIGURE 10, 11DView FIGURE 11), PER procurved in dorsal view ( Figs 10CView FIGURE 10, 11CView FIGURE 11); 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. 11DView FIGURE 11). 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. 11BView FIGURE 11). 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. 10AView FIGURE 10); abdomen of female elongateoval, black, without dorsal scutum, with several light-coloured chevrons posteriorly in female ( Fig. 11AView FIGURE 11); epigastric sclerite developed in female, post-epigastric sclerite, ventral sclerite absent in both sexes, inframamillary sclerite present in female ( Figs 10BView FIGURE 10, 11BView FIGURE 11).

Male palpal tibia cylindrical ( Figs 10View FIGURE 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 11View FIGURE 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 10View FIGURE 10, 11View FIGURE 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.GoogleMaps 

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.GoogleMaps 

Diagnosis. See the generic diagnosis above.

Description. Male from China ( Fig. 10View FIGURE 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. 11View FIGURE 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 10View FIGURE 10 E–H) and female genitalia ( Figs 11View FIGURE 11 E–F) as in the generic description.

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

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Corinnidae

Genus

Medmassa

Loc

Medmassa torta

Jin, Chi, Zhang, Hongli & Zhang, Feng 2019
2019
Loc

Allomedmassa day

Dankittipakul, P. & Singtripop, T. 2014: 21