Messapus mygaloides, Haddad & Grismado, 2025

Haddad, Charles R. & Grismado, Cristian J., 2025, Further additions to the rare dark sac spider genus Messapus Simon, 1897 (Araneae: Corinnidae), Zootaxa 5637 (2), pp. 351-362 : 353-358

Messapus mygaloides sp. nov.

Figures 2–26

Type material. Holotype ♀: TANZANIA: Tanganyika Region: 6 mi. N of Iringa [ca. 07°40’S, 35°40’E], 1475 m a.s.l., 16.XI.1957, leg. E.S. Ross & R.E. Leech ( CAS, TYPE21619 , preparation CJG-2048).

Paratypes: MOZAMBIQUE: Manica Province: Majolele, foot of Mount Sanga , 18°59’S, 33°42’E, 565 m a.s.l., 19.XI.2016, leg. L. Geeraert & M. Jocque (night, village), 1♂ ( MRAC 247734 ) . TANZANIA: Ruvuma Region: Namswea, 10°28’09.9”S, 34°51’46.8”E, 14.XI.2023, leg. F.H. Pretorius (inside offices), 1♂ ( NMBA 19155 ) .

Etymology. The species name refers to the massive, forward-protruding chelicerae in this species (notably in the female, Fig. 6 ), which resemble those of the spider infraorder Mygalomorphae .

Diagnosis. Messapus mygaloides sp. nov. is most similar to M. tigris Haddad & Mbo, 2015 in several respects, and the two species are probably closely related. Both species share a line of six or seven small arrowhead-shaped markings along the midline of the abdomen, which are unique in the genus ( Figs 2 , 5 , 27 ; Haddad & Mbo 2015: figs 1, 2, 8). The epigyne of M. mygaloides sp. nov. has the lateral ridges more widely separated, with angular anterior margins (vs. gently curved in M. tigris ), and defining more distinct copulatory openings with the oval lateral lobes; the spermathecae are also massive, but differ by having anteromedian, nearly spherical pore-bearing receptacles and posteriorly directed median primary spermathecae, with coiled internal ducts, ending in an inconspicuous fertilization duct (cf. Figs 10–14 with Haddad & Mbo 2015: figs 35, 49, 50). Males resemble those of M. tigris in palpal morphology, especially by the sickle-shaped dorsal retrolateral tibial apophysis and the semicircular tegular apophysis retrodistally, but they differ by the embolus being broader, having a more prolateral origin, and by the tegulum lacking the additional thin spike-like prodistal tegular apophysis of M. tigris (cf. Figs 15–17 and 36–39 ).

Female (holotype, Iringa, CAS TYPE21619). Measurements : CL 3.40, CW 3.12, AL 5.25, AW 3.20, TL 8.40, SL 1.84, SW 1.88, CH 0.16, AME–AME 0.14, AME– ALE 0.06, ALE – ALE 0.64, PME–PME 0.26, PME–PLE 0.12, PLE–PLE 0.88, PERW 1.04 , MOQAW 0.54, MOQPW 0.62, MOQL 0.60. Length of leg segments (sequence from femur to tarsus, and total): I 3.16 + 1.52 + 2.40 + 2.24 + 1.12 = 10.44; II 2.88 + 1.40 + 2.04 + 2.08 + 0.96 = 9.36; III 2.44 + 1.24 + 1.92 + 2.24 + 1.00 = 8.84; IV 3.76 + 1.48 + 3.12 + 3.52 + 1.20 = 13.08.

General appearance as in Figs 5–9 . Carapace (in ethanol) yellow-brown, paler laterally and posteromedially, with broad mediolateral, sinuose brown markings, brown marking in front of fovea, and two forwardly diverging bands of silver-white feathery setae. All eyes surrounded by black rings; AER slightly procurved; AME larger than ALE; PER slightly procurved; PME slightly larger than PLE. Chelicerae orange-brown, lighter on the anteromedian margins and on the condyles, with dark brown setae on paturon; cheliceral promarginal pronounced mound present; promargin with four teeth, proximal tooth largest; retromargin with five teeth, proximal largest, separate from remaining teeth that are adjacent and subequal. Endites creamy-brown, cream distally; serrula distinct; labium yellow-brown, cream distally; sternum shield-shaped, broader than long, uniform yellow-brown, with scattered straight brown setae. Legs creamy-yellow, distal segments slightly darker; markings covered in dark squamose setae with brachia, except tarsi, covered in feathery setae; femora with broad dark band at 2/3 their length, scattered small dark spots in proximal half; patellae with dark proximal half; tibiae and metatarsi with broad median dark band and faint narrow distal ring; tarsi uniformly dark, without markings. Leg spination: femora: I pl 1 do 3, II pl 1 do 2, III pl 2 do 3 rl 2, IV do 2 rl 1; tibiae: I and II spineless, III pl 2 rl 2 plv 2 rlv 1 vt 2, IV pl 2 rl 2 plv 2 rlv 0-1 vt 2; metatarsi: I vt 3, II rl 1 rlv 2 vt 3, III pl 1 rl 1 rlv 2 vt 1, IV pl 1 rl 2 plv 2 rlv 2 vt 3. Palp: femora: do 3; patellae: pl 1. Abdomen brown dorsally and laterally, with light, narrow arrowhead-shaped chevrons dorsally and light scattered patches laterally (denser near venter); brown areas covered in dark squamose setae with brachia, with scattered elongate striate scales between them; venter cream, covered in short straight brown setae and cream feathery setae and squamose setae with brachia. Epigyne with widely separated lateral ridges with angular anterior margins, separated by twice their width, with copulatory openings between them and internal oval lateral lobes ( Figs 10 , 12 ); copulatory ducts short, entering massive ST II on their anterior margin; ST II directed posterolaterally, with nearly spherical field of pore-bearing receptacles anteromedially near their base ( Figs 11 , 13 ), internal ducts coiled, leading into posteriorly directed median ST I, ending in inconspicuous fertilization duct posterolaterally ( Figs 13, 14 ).

Male (paratype, Namswea, NMBA 19155). Measurements : CL 3.90, CW 3.30, AL 4.85, AW 2.85, TL 8.28, SL 1.98, SW 1.96, CH 0.19, AME–AME 0.10, AME– ALE 0.03, ALE – ALE 0.65, PME–PME 0.22, PME–PLE 0.16, PLE–PLE 0.95, PERW 1.22 , MOQAW 0.61, MOQPW 0.65, MOQL 0.67. Length of leg segments (sequence from femur to tarsus, and total): I 3.20 + 1.30 + 2.56 + 2.40 + 1.25 = 10.71; II 2.97 + 1.46 + 2.19 + 2.23 + 1.15 = 10.00; III 2.80 + 1.31 + 2.02 + 2.25 + 1.15 = 9.53; IV 3.95 + 1.63 + 3.18 + 3.61 + 1.38 = 13.75.

General appearance as in Figs 2–4 , 18–22 ; carapace (in ethanol) deep wine red, with black mottling, with creamy-grey markings in front of fovea, on sides of eye region and undulating along lateral margins. All eyes surrounded by black rings; AER slightly procurved; AME larger than ALE; PER slightly procurved; PLE slightly larger than PME. Chelicerae wine red, lighter on anteromedian margins and condyles, with dark brown setae on paturon; cheliceral promarginal pronounced mound present; promargin with three teeth, decreasing in size distally, proximal tooth largest, slightly separate from median tooth, median and distal teeth adjacent; retromargin with five teeth, proximal largest, slightly separated from second tooth, third to fifth teeth subequal and on common base. Endites and labium orange-brown, paler towards inner margins, cream distally; serrula distinct; endites depressed laterally, labium semi-circular, with basolateral depressions; sternum shield-shaped, as broad as long, orange, with darker margins and dense black mottling. Coxae and trochanters all deep yellow, with black mottling; femora yellow, darker distally; patellae to tarsi deep yellow-orange, with black mottling; all tibiae and metatarsi with broad black median band and proximal and distal creamy-grey rings, tarsi with broad median black band only. Leg spination: femora: I pl 1 do 3-4, II pl 1 do 2, III pl 2 do 3 rl 1, IV pl 1 do 2; all patellae with single fine dorsal distal seta; tibiae: I plv 3 rlv 3 very short spinules, II spineless, III pl 2 rl 2 plv 2 rlv 1 vt 2, IV pl 2 rl 2 plv 2 vt 2; metatarsi: I rlv 2 vt 3, II rlv 1 vt 3, III pl 1 rl 1 plv 1 rlv 2 vt 3, IV pl 1 rl 2 plv 2 rlv 2 vt 3. Palpal spination: femora pl 1 do 2, patellae pl 1, tibiae pl 1 plv 1, tarsi plv 1. Abdomen dark brown, almost black dorsally, with narrow cream arrowhead-shaped chevron markings along midline (setae abraded in posterior half following preservation, cf. Figs 2 and 18 ) and light scattered patches laterally; dorsal scutum bright orange, extending just past midpoint of dorsum; brown areas covered in dark elongate striate scales and squamose setae with brachia; venter cream, covered in short straight setae and squamose setae with brachia. Male palpal femora and patellae yellow, tibiae and tarsi deep orange-brown; tibia with short subrectangular prolateral apophysis ( Figs 15 , 23 ), longitudinal ventral depression ( Figs 16 , 24 ), finger-like ventral RTA with pointed tip and large sickle-shaped dorsal RTA with sharp, distally directed tip ( Figs 17 , 25, 26 ); tegulum oval, with complex sperm duct with numerous loops, leading to broad, flattened embolus originating prolaterally distally, curving towards retrolateral side; broad semicircular tegular apophysis at distal end of tegulum; conductor absent ( Figs 16 , 24 ).

Variation. The paratype male from Mozambique has a total length of 7.70.

Sequence data. The paratype male from Namswea sequenced successfully for COI ( NMBA 19155 , SPIZA2084- 24 ).

Distribution. Although the female and male of this species have not yet been collected together, the two Tanzanian localities (Iringa and Namswea) are reasonably close together and would suggest they represent one species. Also collected from northwestern Mozambique ( Fig. 1 ).

Figures

FIGURE 1. Distribution of Messapus martini (red circles), M. mygaloides sp. nov. (green circles) and M. tigris (yellow circles) in the Afrotropical Region.

FIGURES 2–4. Habitus of live Messapus mygaloides sp. nov. male from Namswea, Tanzania: 2. Dorsal view; 3. Dorsolateral view; 4. Eye region, anterior view. Photos: Frans Pretorius.

FIGURES 5–11. Somatic and genitalic morphology of Messapus mygaloides sp. nov., female holotype from Iringa, Tanzania: 5. Habitus, dorsal view; 6. Carapace, lateral view; 7. Eye region and chelicerae, dorsal view; 8. Mouthparts, ventral view; 9. Habitus, ventral view; 10. Epigyne, ventral view; 11. Same, dorsal view. Abbreviations: CPPM—cheliceral promarginal pronounced mound; LL—oval lateral lobe; LR—lateral ridge.

FIGURES 12–17. Genitalic morphology of Messapus mygaloides sp. nov., female holotype from Iringa and male paratype from Namswea, Tanzania: 12. Epigyne, ventral view; 13. Same, dorsal view; 14. Detail of right spermatheca; 15. Left palp, prolateral view; 16. Same, ventral view; 17. Same, retrolateral view. Abbreviations: CD—copulatory duct; CO—copulatory opening; dRTA—dorsal retrolateral tibial apophysis; EM—embolus; FD—fertilization duct; LL—oval lateral lobe; LR—lateral ridge; PBR—pore-bearing receptacle; PTA—prolateral tibial apophysis; SD—sperm duct; ST I—primary spermatheca; ST II—secondary spermatheca; rTA—retrodistal tegular apophysis; vRTA—ventral retrolateral tibial apophysis.

FIGURES 18–26. Somatic and genitalic morphology of Messapus mygaloides sp. nov., male paratype from Namswea, Tanzania: 18. Habitus, dorsal view; 19. Carapace, dorsal view; 20. Habitus, lateral view; 21. Mouthparts, ventral view; 22. Dorsal abdominal integument; 23. Left palp, prolateral view; 24. Same, ventral view; 25. Same, ventrolateral view; 26. Same, retrolateral view. Abbreviations: CPPM—cheliceral promarginal pronounced mound; ESS—elongate striate scales; SSB— squamose setae with brachia.

FIGURES 27–35. Somatic and genitalic morphology of Messapus tigris, male from Shakawe, Botswana: 27. Habitus, dorsal view; 28. Same, lateral view; 29. Same, ventral view; 30. Leg I, lateral view; 31. Left palp, prolateral view; 32. Same, ventral view; 33. Same, retrolateral view; 34. Same, dorsal view; 35. Detail of retrolateral tibial apophysis, retrolateral view.

FIGURES 36–39. Genitalic morphology of Messapus tigris, males from Shakawe, Botswana (36, 37, 39) and St James Mission, Zimbabwe (38): 36. Left palp, prolateral view; 37. Same, ventral view; 38. Variation of base of retrolateral tibial apophysis, ventral view; 39. Left palp, retrolateral view.Abbreviations: dRTA—dorsal retrolateral tibial apophysis; EM—embolus; pTA— prodistal tegular apophysis; PTA—prolateral tibial apophysis; SD—sperm duct; rTA—retrodistal tegular apophysis; vRTA— ventral retrolateral tibial apophysis.