Xenoctenus Mello-Leitão, 1938

Faustino-Magalhaes, Mayara D., Piacentini, Luis N. & Santos, Adalberto J., 2024, The desert wolf-spider genus Xenoctenus: two endemic species from the Brazilian Caatinga, and a redescription of the type-species, X. unguiculatus (Araneae: Xenoctenidae), Zootaxa 5399 (5), pp. 517-539 : 519

Genus Xenoctenus Mello-Leitão, 1938

Type species. Xenoctenus unguiculatus Mello-Leit „o, 1938, by monotypy (considered a nomen dubium by Carcavallo & Martínez 1967 but here validated).

Emended diagnosis. Xenoctenus species can be differentiated from other Xenoctenidae by the presence of flexible tarsi in both sexes ( Fig. 10B ). Males can be distinguished from other xenoctenids by the tip of the cymbium with a thick scopula, without macrosetae ( Figs 5 , 7A–C , 8 , 11A–C , 12A–B , 13A, C ). The palps also differ by the retrolateral tegular projection (RTP) being long, concave and located anteriorly ( Figs 4A–C , 7A–C , 8 , 11A–C , 12A– B , 13A, C ). Females differ by a strongly sclerotized epigynum and the primary spermathecae long, with irregular margins, and secondary spermathecae anteriorly positioned ( Figs 6 , 9 , 10A , 12C–D ).

Species included. Xenoctenus gomezraggioi Carcavallo & Martínez, 1967 , Xenoctenus kaatinga Faustino-Magalhaes & Santos sp. nov., Xenoctenus unguiculatus Mello-Leit „o, 1938, Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov., Xenoctenus pampeanus Mello-Leit „o, 1940; Xenoctenus patagonicus Mello-Leit „o, 1940 (nomen dubium); Xenoctenus proseni Carcavallo & Martínez, 1967 .

Distribution. The genus is known mostly from xeric environments in Argentina and northeastern Brazil (Caatinga domain), with isolated records in southern Brazil and northeastern Argentina ( Figs 14–16 ). Records from Bolivia and Colombia ( Carcavallo & Martínez 1967) require further confirmation.

Figures

FIGURE 4. Xenoctenus unguiculatus Mello-Leit„o, 1938. Male from Reserva Natural y Cultural Bosques Telteca, Mendoza, Argentina (MACN-Ar 35619).A, palp, prolateral. B, ventral. C, retrolateral. D, habitus, dorsal view.Abbreviations: E, embolus; MA, median apophysis; RTP, retrolateral tegular projection; StLL, subtegular locking lobe. White star on tegular distal division (TDD).

FIGURE 5. Xenoctenus unguiculatus Mello-Leit„o, 1938, male from PN Sierra de las Quijadas, San Luis, Argentina (MACN- Ar 45013).A, C, palp.A, prolateral. B, ventral. C, retrolateral.Abbreviations:C, conductor; E, embolus; MA, median apophysis; RTA, retrolateral tibial apophysis; RTP, retrolateral tegular projection. White star on tegular distal division (TDD).

FIGURE 6. Xenoctenus unguiculatus Mello-Leit„o, 1938, female epigynum (A, C) and internal genitalia (B, D). A, B, female from Caucete, San Juan, Argentina (MACN-Ar 35624). A, ventral. B, dorsal. C, D, female from PN Sierra de las Quijadas, San Luis, Argentina (MACN-Ar 45013). C, ventral. D, dorsal. Abbreviations: CD, copulatory ducts; LL, lateral lobes; LLE, lateral lobes extension; MF, median field; S1, primary spermathecae; S2, secondary spermathecae.

FIGURE 7. Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov. A–C, male from Jaguaribe, Ceará, Brazil (CNHUFPI 2521), bleached palp. A, prolateral. B, ventral. C, retrolateral. D, male from Castelo do Piauí, Piauí, Brazil (CHNUFPI 2385), habitus, dorsal. Abbreviations: C, conductor; E, embolus; ELL, embolar locked lobe; MA, median apophysis; RTA, retrolateral tibial apophysis; RTP, retrolateral tegular projection; StLL, subtegular locking lobe. White star on tegular distal division (TDD).

FIGURE 8. Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov., male from Pentecoste, Ceará, Brazil (UFMG 20950). A–C, expanded palp. A, prolateral. B, ventral. C, retrolateral. Abbreviations: C, conductor; E, embolus; ELL, embolar locked lobe; MA, median apophysis; RTA, retrolateral tibial apophysis; RTP, retrolateral tegular projection; StLL, subtegular locked lobe. White star on tegular distal division (TDD).

FIGURE 9. Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov., bleached female epigynum (A, C, E) and internal genitalia (B, D, F). A–B, female from Jaguaribe, Ceará, Brazil (CNHUFPI 2521). A, ventral. B, dorsal. C–D, female from Guaribas, Piauí, Brazil (IBSP 56027). C, ventral. D, dorsal. E–F, female from Guaribas, Piauí, Brasil (CNHUFPI 2398). E, ventral. F, dorsal. Abbreviations: CD, copulatory ducts; LL, lateral lobes; LLE, lateral lobes extension; MF, median field; MG, median groove; S1, primary spermathecae; S2, secondary spermathecae.

FIGURE 10. Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov. from Jequié, Bahia, Brazil (UFMG 13690). A, female epigynum, not bleached, ventral. B, leg I, flexible tarsus.

FIGURE 11. Xenoctenus kaatinga Faustino-Magalhaes & Santos sp. nov., male from Alvorada do Gurguéia, Piauí, Brazil (CNHUFPI 2450).A–C, bleached palp. A, prolateral. B, ventral. C, retrolateral. D. habitus, dorsal.Abbreviations: C, conductor; E, embolus; MA, median apophysis; RTA, retrolateral tibial apophysis; RTP, retrolateral tegular projection; StLL, subtegular locking lobe. White star on tegular distal division (TDD).

FIGURE 12. Xenoctenus kaatinga Faustino-Magalhaes & Santos sp. nov., male and female from Alvorada do Gurguéia, Piauí, Brazil (CNHUFPI 2448). A–B, expanded, bleached male palp. A, prolateral. B, retrolateral. C, bleached female epigynum, ventral. D, bleached internal female genitalia, dorsal. Abbreviations: C, conductor; CD, copulatory ducts; E, embolus; ELL, embolar locked lobe; LL, lateral lobes; LLE, lateral lobes extension; MA, median apophysis; MF, median field; RTA, retrolateral tibial apophysis; RTP; retrolateral tegular projection; S1, primary spermathecae; S2, secondary spermathecae; St, subtegulum, StLL, subtegular locking lobe; T, tegulum. White star on tegular distal division (TDD).

FIGURE 13. A–B, Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov., male and female from Itacuruba, Pernambuco, Brazil (UFMG 20060). A, male palp, ventral. B, female internal genitalia, dorsal. C–D, Xenoctenus kaatinga Faustino-Magalhaes & Santos sp. nov., male and female from Alvorada do Gurguéia, Piauí, Brazil (CHNUFPI 2448). C, male palp, ventral. D, female internal genitalia, dorsal. Abbreviations: C, conductor; CD, copulatory ducts; E, embolus; MA, median apophysis; RTP, retrolateral tegular projection; StLL, subtegular locking lobe; S1, primary spermathecae; S2, secondary spermathecae. Black star on tegular distal division (TDD).

FIGURE 14. Geographic distribution records of Xenoctenus Mello-Leit„o, 1938 in South America.

FIGURE 15. Geographic distribution records of Xenoctenus unguiculatus Mello-Leit„o, 1938 inArgentina and southern Brazil. The “?” indicates that the specific locality is unknown as it was reported only as the Province of Buenos Aires.

FIGURE 16. Geographic distribution records of Xenoctenus kaatinga Faustino-Magalhaes & Santos sp. nov. and Xenoctenus vittatus (Mello-Leit„o, 1936) comb. nov. on northeastern Brazilian Caatinga domain. The type locality of X. vittatus is uncertain, as it is reported only as the Brazilian state of Paraiba.