Messapus, Simon, 1898

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 : 360-361

Updated key to the species of Messapus

1. Males (males of M. meridionalis Haddad & Mbo, 2015 and M. seiugatus Haddad & Mbo, 2015 unknown).............. 2

- Females............................................................................................. 7

2. Palp with single elongate slender RTA; embolus very long, originating prolaterally, curving in broad arc distally and ending midway along the retrolateral margin of the tegulum ( Haddad & Mbo 2015: figs 37, 38, 43, 44).................................................................................................. M. megae Haddad & Mbo, 2015

- Palpal tibia with more than one apophysis; embolus shorter.................................................... 3

3. Palpal tibia bearing four retrolateral apophyses, dorsal RTA bifid; embolus short, needle-shaped, obliquely situated beneath sclerotised tegular apophysis ( Haddad 2005: figs 4–6); large spiders,> 11.7 mm in length........ M. natalis (Pocock, 1898)

- Palpal tibia bearing two or three retrolateral apophyses, dorsal RTA not bifid; embolus not hidden beneath tegular apophysis, slightly curved and flattened; medium to large spiders, <10 mm in length......................................... 4

4. Palpal tibia with two apophyses; dorsal RTA massive, sickle-shaped in retrolateral view, as long as dorsal surface of tibia and approximately half the length of the cymbium ( Figs 17 , 39 ).................................................... 5

- Palpal tibia with three apophyses; dorsal RTA shorter, triangular ( Haddad & Mbo 2015: fig. 54) or hatchet-shaped ( Haddad 2013: fig. 38), clearly shorter than dorsal surface of tibia and less than half the length of the cymbium.................. 6

5. Tegulum with distinct spike-like prodistal tegular apophysis; embolus originating mediodistally, axis directed approximately towards 1 o’clock ( Figs 32 , 37 ).................................................. M. tigris Haddad & Mbo, 2015

- Tegulum without prodistal tegular apophysis; embolus originating prodistally, broad and flattened, slightly curved and transversely oriented ( Figs 16 , 24 )...................................................... M. mygaloides sp. nov.

6. Dorsal RTA triangular, originating dorsally above two smaller teeth-like ventral apophyses ( Haddad & Mbo 2015: figs 39, 40, 53, 54).................................................................... M. tropicus Haddad & Mbo, 2015

- Dorsal RTA stout, hatchet-shaped, slightly curved ventrally in retrolateral view, originating dorsally above tongue-like ventral RTA, with small lobed apophysis between them proximally ( Haddad 2013: figs 36, 37)............ M. martini Simon, 1898

7. Epigyne with horseshoe-shaped ridges; cheliceral promarginal pronounced mound absent............................ 8

- Epigyne with oval- or slit-shaped ridges; cheliceral promarginal pronounced mound present.......................... 9

8. Lateral margins of epigynal ridges almost parallel but converging slightly posteriorly, forming subrectangular atrium ( Haddad & Mbo 2015: figs 33, 45); copulatory ducts longitudinal to epigynal axis; ST II without anterior pore-bearing receptacle ( Haddad & Mbo 2015: fig. 46)............................................. M. meridionalis Haddad & Mbo, 2015

- Lateral margins of epigynal ridges broadening medially, forming diamond-shaped atrium ( Haddad 2013: fig. 34); copulatory openings obliquely oriented to epigyne axis; ST II with anterior pore-bearing receptacle ( Haddad 2013: fig. 35)............................................................................................ M. martini Simon, 1898

9. Epigyne ventrally with strongly sclerotized ridges forming complete ovals, directed anterolaterally along their axis....... 10

- Epigyne ventrally with ridges forming incomplete ovals or with curved ridges.................................... 11

10. Epigynal ridges touching medially ( Haddad 2005: figs 1, 2); spermathecae linked by broad median U-shaped tube ( Haddad 2005: fig. 3); large spiders,> 15 mm in length........................................... M. natalis (Pocock, 1898)

- Epigynal ridges clearly separated ( Haddad & Mbo 2015: fig. 41); spermathecae not connected by broad median U-shaped tube, but projecting anterolaterally ( Haddad & Mbo 2015: fig. 42); small spiders, ca. 7 mm in length.................................................................................................. M. megae Haddad & Mbo, 2015

11. Epigyne with two widely separated oblique incomplete oval ridges, with their anterior margins directed anteromesally; ST II large, suboval, situated laterally ( Figs 12, 13 ; Haddad & Mbo 2015: figs 35, 49, 50)............................... 12

- Epigyne with curved epigynal ridges, oriented more or less parallel to body axis; ST II either small, round and medially situated ( Haddad & Mbo 2015: fig. 48) or with large lateral extensions projecting posteriorly ( Haddad & Mbo 2015: fig. 52)...... 13

12. Epigynal ridges with distinct oval lateral lobe positioned posterior to lateral ridge ( Figs 10 , 12 )..... M. mygaloides sp. nov.

- Epigynal ridges with narrow fringe along their anterior margin, without oval lateral lobe (Fig. 46; Haddad & Mbo 2015: fig. 49)......................................................................... M. tigris Haddad & Mbo, 2015

13. Epigyne with small ridges, curved inwards, copulatory openings anteriorly in ridges ( Haddad & Mbo 2015: figs 34, 47)............................................................................. M. seiugatus Haddad & Mbo, 2015

- Epigyne with large ridges, curved outwards, forming ovoid median atrium, with copulatory openings posteriorly in ridges ( Haddad & Mbo 2015: figs 36, 51)............................................. M. tropicus Haddad & Mbo, 2015

Figures

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 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.

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 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 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.