Medmassa postica Kadam, Tripathi & Sankaran, 2024

Sankaran, Pradeep M., Kadam, Gautam & Tripathi, Rishikesh, 2024, First records of Medmassa Simon, 1887 from India, with the description of two new species (Araneae: Corinnidae), Zootaxa 5433 (1), pp. 133-143 : 141-142

Medmassa postica Kadam, Tripathi & Sankaran sp. nov.

Figs 1C, E–F, H , 6–8

Etymology. The specific name is an adjective and referring to the creamy-white posterior part of the opisthosoma of the new species ( Fig. 6A ). Latin posticus = posterior.

Type material. Holotype ♀ (ZSI/ WGRC /I. R.INV.26129) from INDIA: Tamil Nadu: Kanniyakumari / Kanyakumari: Thovalai : near Anjaneyar temple (8°13’33’’N, 77°30’24’’E; 84 m a.s.l.), 30.VI.2022, leg. G. Kadam, from rock, by hand.

Diagnosis. Medmassa postica sp. nov. is closely related to M. insignis (Thorell, 1890) by having the copulatory openings placed above the anterior margin of spermathecae, long copulatory ducts, and subtriangular spermathecae, but can be separated by the parallel copulatory ducts (vs. posteriorly converging in M. insignis ) and the spermathecae with a smoothly rounded anterior margin (vs. pointed in M. insignis ) (cf. Figs 6H–J , 7A, B and Deeleman-Reinhold 2001: fig. 530). Male: Unknown.

Description. Female in alcohol ( Fig. 6A–G ). Carapace, eye region, clypeus, chilum, chelicerae, endites, labium, sternum brown; carapace with indistinct black blotches; thoracic part marginally dark yellow; leg and palpal segments gradually deepen in colour from yellow-brown proximally to brown distally; dorsum, median part of sides and venter of opisthosoma black, rear end, anterior and posterior parts of sides and venter creamy white ( Fig. 6B ); spinnerets creamy-white with black shade; anal tubercle creamy white; colulus black. Carapace sparsely covered with black setae; cephalic part squarish, thoracic part circular ( Fig. 6A, D ). Fovea short, straight, longitudinal. Chilum narrow, inverted triangular ( Fig. 6C ). Cheliceral boss prominent. Cheliceral promargin with three teeth, retromargin with four ( Fig. 6E ). Endites diverging, with distolateral hair tuft ( Fig. 6F ). Sternum rounded, rebordered, with W-shaped anterior margin, covered with black setae ( Fig. 6F ). Opisthosoma oval, covered with fine appressed setae ( Fig. 6A ). Tibiae I–II with paired long ventrolateral spines ( Fig. 6G ); all tarsi without scopulae, with claw tuft ( Fig. 6G ). Body length 6.98. Carapace 3.43 long, 3.19 wide. Opisthosoma 3.55 long, 2.45 wide. Eye sizes and interdistances: ALE 0.18, AME 0.23, PLE 0.20, PME 0.15; ALE–PLE 0.06, AME–ALE 0.02, AME–AME 0.09, AME–PME 0.12, PME–PLE 0.10, PME–PME 0.19. Clypeus height at AMEs 0.25, at ALEs 0.14. Chilum 0.02 long, 0.36 wide. Chelicerae 1.36 long. Length of palp and legs: palp 4.75 [1.52, 0.78, 1.00, 1.45], I 10.23 [2.98, 1.20, 2.69, 2.19, 1.17], II 9.45 [2.80, 1.13, 2.35, 1.98, 1.19], III 10.97 [2.93, 1.21, 2.40, 2.84, 1.59], IV 12.39 [3.21, 1.27, 2.69, 3.37, 1.85]. Leg formula: 4312. Spination of palp: femur pld 1 plv 1 do 2 rlv 4, patella pl 1 pld 1 do 1, tibia pl 1 pld 2 do 1 rlv 1, tarsus pl 1 pld 1. Spination of legs: femora I–II pl 1 pld 1 do 2, III pld 1 do 3 rld 3, IV do 3 rld 1; patellae I–IV spineless; tibia I plv 8 rlv 7, II plv 6 rlv 5, III plv 3 rl 2 rlv 2, IV plv 2 rl 2 rlv 1; metatarsi I–II plv 2 rlv 2, III plv 3 rl 1 rlv 3 vt 1, IV plv 1 rl 1 rlv 3 vt 1; tarsi I–IV spineless.

Female genitalia ( Figs 6H–J , 7A, B ): epigyne forming triangular plate, with convex posterior margin having deep median depression ( Figs 6H, I , 7A ). Copulatory openings small, separated from each other by twice their diameter, lying above anterior margin of spermathecae, with thickened rims ( Figs 6H, I , 7A ). Copulatory ducts long, parallel to each other, and close to spermathecae ( Figs 6J , 7B ). Spermathecae large, subtriangular, contiguous posteriorly ( Figs 6J , 7B ). Fertilization ducts diverging ( Fig. 7B ).

Distribution. Known only from the type locality ( Fig. 8 ).

Figures

FIGURE 1. Field photographs of Medmassa spp.. A–B, D, G M. sagax Tripathi, Kadam & Sankaran sp. nov.: A & B paratype female in different views; D retreat; G collecting locality. C, E–F, H M. postica Kadam, Tripathi & Sankaran sp. nov.: C holotype female; E–F retreats (F retreat with spider resting inside); H collecting locality. Figures are not to scale. Arrows indicate retreats. Photo credits: A–B, D, Rishikesh Tripathi, C, E–F Gautam Kadam, G Roshin Tom, H Vinod Sadhasivan.

FIGURE 6. Medmassa postica Kadam, Tripathi & Sankaran sp. nov., holotype female. A Habitus, dorsal view; B Same, retrolateral view; C Same, frontal view; D Eye area, dorsal view; E Left chelicera, retrolateral view; F Prosoma showing labium, endites and sternum, ventral view; G Left leg I showing long spines on tibia, prolateral view; H Intact epigyne, ventral view; I Same, after clearing, ventral view; J Epigyne, dorsal view. Scale bars: A–B 2 mm; C, E–G 1 mm; D 0.5 mm; H–J 0.2 mm.

FIGURE 7. Medmassa postica Kadam, Tripathi & Sankaran sp. nov., epigyne of holotype female in ventral (A) and dorsal views (B). Abbreviations: CD, copulatory duct; CO, copulatory opening; FD, fertilization duct; S, spermatheca. Scale bars: A–B, 0.2 mm.

FIGURE 8. Distribution of the genus Medmassa in India. ● M. sagax Tripathi, Kadam & Sankaran sp. nov.; ■ M. postica Kadam, Tripathi & Sankaran sp. nov..