Jocquestus obliquus, Lyle & Haddad, 2018

Lyle, Robin & Haddad, Charles R., 2018, Jocquestus, a new genus of trachelid sac spiders from the Afrotropical Region (Arachnida: Araneae), Zootaxa 4471 (2), pp. 309-333 : 322-323

Jocquestus obliquus sp. nov.

urn:lsid:zoobank.org:act:67CA925C-D192-4CF2-AD2D-C29C16B2E6CA

Figs 15, 16 , 56–60

Etymology. This species name is derived from the Latin for “oblique”, referring to the slanting, 45° angle of the epigynal ridges of the female epigyne.

Diagnosis. Males of J. obliquus sp. nov. can be easily recognized by the uniquely coiled embolus ( Fig. 57 ), which is linear in all other Jocquestus species. The female can be recognised by the comma-shaped ST II that are narrower at their base than anteriorly, resulting in a clear median space separating their proximal parts ( Fig. 59 ). Further, the ducts linking ST I and II are placed halfway between the midline and lateral margins of the ST ( Fig. 60 ), as opposed to medially in congeners.

Male (paratype, Mkomazi Game Reserve, OUMNH). Measurements: CL 1.56, CW 1.13, AL 1.71, AW 1.15, TL 3.24, FL 0.06, SL 0.78, SW 0.63, AME–AME 0.03, AME–ALE 0.02, ALE–ALE 0.22, PME–PME 0.07, PME–PLE 0.06, PLE–PLE 0.39.

Length of leg segments (sequence from femur to tarsus, and total): I 0.94 + 0.44 + 0.65 + 0.52 + 0.40 = 2.95; II 0.87 + 0.42 + 0.63 + 0.56 + 0.38 = 2.86; III 0.70 + 0.38 + 0.48 + 0.56 + 0.27 = 2.39; IV 0.82 + 0.44 + 0.63 + 0.74 + 0.30 = 2.93.

Carapace orange-brown, with faint black mottling ( Fig. 15 ); surface finely wrinkled, with sparse short, fine setae; fovea short, broad, slightly darker than carapace, at two thirds CL. All eyes surrounded by black rings; AER procurved; AME slightly smaller than ALE; clypeus height slightly greater than AME diameter; AME separated by distance slightly less than half their diameter; AME separated from ALE by distance equal to one-quarter AME diameter; PER recurved, PLE slightly larger than PME; PME separated by distance slightly less than their diameter; PME separated from PLE by distance slightly less than PME diameter. Chelicerae orange-brown, anterior surface with scattered long, fine setae; two promarginal teeth, distal tooth largest; two smaller retromarginal teeth, proximal tooth largest. Sternum yellow-brown, with faint black mottling, darker along border; surface smooth, with scattered short, fine setae. Abdomen dark grey, with two paired cream markings, first subtriangular pair anteriorly, second transverse pair anterior to midpoint ( Fig. 15 ); two pairs of yellow-brown sigilla, first pair at one-third abdomen length, second pair at midpoint of abdomen; surface sparsely covered with short, fine setae. Legs I to IV with femora orange-brown, paler proximally, with grey mottling dorsally and laterally; patellae to metatarsi I–IV yellow-brown, with faint grey mottling; tarsi uniform orange-brown; all segments covered with short, fine setae; relatively dense ventral scopulae on distal metatarsi and tarsi legs III and IV; leg spination: tibiae: I plv 8 rlv 3 cusps; metatarsi: I plv 8 cusps; tarsi: I plv 1 cusp ( Fig. 56 ). Palp orange-brown; RPA subquadrangular in retrolateral view, ventral end slightly pointed; tibia with small rounded retrolateral-dorsal RTA, with small sharp projection on its dorsal surface; embolus originating prolaterally on tegulum, parallel-sided long its length, distal half forming broad coil ending near cymbium tip; embolus associated with narrow membranous conductor, originating prolaterally on tegulum near embolus base ( Figs 57, 58 ).

Female (holotype, Mkomazi Game Reserve, MRAC 211323). Measurements: CL 1.47–1.55, CW 1.14– 1.15, AL 1.49–1.90, AW 1.08–1.25, TL 2.96–3.60, FL 0.04–0.05, SL 0.78–0.85, SW 0.61–0.68, AME–AME 0.03, AME–ALE 0.03, ALE–ALE 0.25, PME–PME 0.08, PME–PLE 0.08, PLE–PLE 0.43.

Length of leg segments (sequence from femur to tarsus, and total): I 0.97 + 0.43 + 0.70 + 0.55 + 0.48 = 3.13; II 0.93 + 0.43 + 0.65 + 0.60 + 0.43 = 3.04; III 0.73 + 0.40 + 0.45 + 0.58 + 0.30 = 2.46; IV 0.90 + 0.43 + 0.70 + 0.78 + 0.35 = 3.16.

Carapace reddish-brown ( Fig. 16 ); surface finely granulate, covered with short fine setae; fovea short, indistinct, slightly darker than carapace, at two thirds CL; ocular region brown; AER slightly recurved, almost straight; AME and ALE equal in size; clypeus height approximately equal to AME diameter; AME separated by distance equal to 0.7 their diameter; AME separated from ALE by distance equal to 0.4 AME diameter; PER recurved, PLE slightly larger than PME; PME separated by distance slightly larger than their diameter; PME separated from PLE by distance equal to 1.4 PME diameter. Chelicerae brown, anterior surface with sparse long, fine setae; two promarginal teeth, distal tooth largest; two retromarginal teeth, proximal tooth largest. Sternum pale brown, darker towards borders; surface smooth, with scattered short, fine setae. Abdomen dark grey, with two pairs of pale yellow sigilla, anterior and posterior to midpoint of abdomen ( Fig. 16 ). Legs I to IV uniform brown, femora darker than other segments; relatively dense ventral scopulae on metatarsi and tarsi of all legs, more prominent on legs III and IV; regular leg spines, cusps absent. Other characters as for male. Epigyne weakly sclerotised; epigynal ridges and CO at 45° angle to epigastric fold, CO situated laterally; large ST II connected with lateral entrance ducts, with folded median ducts connecting ST I and ST II; ST I bilobed when examined dorsally ( Figs 59, 60 ).

Type material. Holotype: ♀: TANZANIA: Mkomazi Game Reserve , near Dindira Dam, 04°00'S, 38°00'E, leg. A. Russell-Smith, 25.I.1996 (in gall on Acacia drepanolobium ) ( MRAC 211323 ).

Paratypes: TANZANIA: Mkomazi Game Reserve , 03°55'S, 37°48'E, leg. G.C. Mc Gavin, 9.IV.1995 (canopy fogging 2/28, Combretum molle ), 1♀ ( OUMNH) ; same data but canopy fogging 2/30, Combretum molle , 1♂ ( OUMNH) .

Distribution. Known only from the type locality ( Fig. 70 ).

Habitat and biology. An arboreal species collected from Vachellia drepanolobium and Combretum molle in savanna habitats in northern Tanzania.

Figures

FIGURE 70. Distribution of the genus Jocquestus gen. nov. in the Afrotropical Region: J. capensis sp. nov. (black circles), J. griswoldi sp. nov. male (yellow circle), J. harrisi sp. nov. (black square), J. incurvus sp. nov. (yellow squares), J. obliquus sp. nov. (black star), J. roeweri (Lawrence, 1938) comb. nov. (yellow stars) and J. schenkeli (Lessert, 1923) comb. nov. (black triangles).

FIGURES 9–20. Digital microscope photographs of the dorsal habitus of Jocquestus gen. nov. species. 9. J. capensis sp. nov., male; 10. Same, female; 11. J. griswoldi sp. nov., male; 12. J. harrisi sp. nov., female; 13. J. incurvus sp. nov., male; 14. Same, female; 15. J. obliquus sp. nov., male; 16. Same, female; 17. J. roeweri (Lawrence, 1938) comb. nov., male; 18. Same, female; 19. J. schenkeli (Lessert, 1923) comb. nov., male; 20. Same, female.

FIGURES 56–60. Jocquestus obliquus sp. nov. male (56–58) and female (59, 60): 56. Schematic representation of cusp arrangement on legs I and II; 57. Left palp, ventral view; 58. Same, retrolateral view; 59. Epigyne, ventral view; 60. Vulva, dorsal view. Scale bars = 0.1 mm.