Orthobula aethiopica, Haddad & Jin & Platnick, 2022

Haddad, Charles R., Jin, Chi & Platnick, Norman I., 2022, A revision of the spider genus Orthobula Simon, 1897 (Araneae: Trachelidae) in the Afrotropical Region. I. Continental species, Zootaxa 5133 (3), pp. 355-382 : 361-364

Orthobula aethiopica sp. nov.

Figs 1, 2 , 54–58

Diagnosis. Females of O. aethiopica sp. nov. share with those of O. milloti a broad, semicircular anterior ridge in the epigyne, but can be distinguished by the CD being about twice as long as the width of the SBB, while approximately equal to the width of the SBB in O. milloti (compare Figs 54 and 90 ). Males of O. aethiopica sp. nov. most closely resemble those of O. calceata in the slightly undulating embolus in ventral view ( Figs 57 , 68 ), but can be distinguished by the shape of the RFA, which is longer and bifid, with a strongly pronounced distal tooth in O. aethiopica sp. nov. ( Fig. 58 ), while shorter and hook-shaped in O. calceata ( Fig. 69 ).

Etymology. The species name is derived from the country of origin, Ethiopia.

Female (holotype, Addis Ababa, BMNH). Measurements: CL 0.98, CW 0.74, AL 1.03, AW 0.73, TL 1.95, PERW 0.33, MOQAW 0.13, MOQPW 0.15, MOQL 0.14. Length of leg segments: I 0.62 + 0.25 + 0.54 + 0.48 + 0.29 = 2.18; II 0.41 + 0.24 + 0.45 + 0.40 + 0.28 = 1.78; III 0.46 + 0.22 + 0.33 + 0.38 + 0.27 = 1.66; IV 0.62 + 0.23 + 0.54 + 0.57 + 0.31 = 2.27.

Colour: carapace dark brown, with reticulated black mottled pattern; chelicerae dark brown; endites and labium slightly paler brown than chelicerae, cream distally; sternum dark brown, with black mottled margins and faint mottling centrally; palps dark yellow-brown; legs with femora, patellae and tibiae orange-brown, with dense black mottling laterally; distal ends of femora and tibiae, and basal end of patellae, with yellow rings; metatarsi and tarsi yellow, metatarsi with faint black mottling; abdomen black dorsally, with pair of cream anterolateral patches and transverse cream band at midpoint; venter cream, with small mottled grey patch in front of spinnerets; spinnerets cream.

Leg spination: femora and patellae: spineless; tibiae: I plv 5 rlv 4, II plv 4 rlv 4; metatarsi: I plv 4 rlv 4, II plv 4 rlv 4; tarsi: I plv 3 rlv 3, II plv 3 rlv 3.

Epigyne with lateral CO in broad semi-circular anterior epigynal ridge ( Fig. 54 ); CD initially curving posteromesally, then bending sharply and diverging slightly before passing round SBB at centre of epigyne; SBB separated by approximately half their width; CD approximately twice as long as width of SBB; BU large and oval, with stalk-like accessory gland on their anteromesal surface; SBB connected to ST I by short looping ducts, entering transversely oval ST I on their mesal surface ( Fig. 55 ).

Male (paratype, Addis Ababa, BMNH). Measurements: CL 0.86, CW 0.68, AL 0.87, AW 0.60, TL 1.72, PERW 0.28, MOQAW 0.11, MOQPW 0.16, MOQL 0.14. Length of leg segments: I 0.55 + 0.22 + 0.48 + 0.40 + 0.26 = 1.91; II 0.48 + 0.21 + 0.36 + 0.35 + 0.26 = 1.66; III 0.40 + 0.19 + 0.29 + 0.33 + 0.21 = 1.42; IV 0.49 + 0.22 + 0.42 + 0.51 + 0.27 = 1.91.

Colour: carapace deep orange-brown, with reticulated black mottled pattern; chelicerae orange-brown; endites and labium slightly paler than chelicerae, cream distally; sternum orange-brown, with black mottled margins and mottling centrally; palps deep yellow-brown; anterior legs slightly darker than posteriors; legs with femora, patellae and tibiae yellow-brown, with black mottling laterally; distal ends of femora and tibiae, and basal end of patellae, with yellow rings; metatarsi and tarsi yellow; abdomen black dorsally, with pair of cream anterolateral patches and pair of transverse cream bands at midpoint, separated medially; venter cream, with large grey patch in front of spinnerets and black mottling on epigastric plate; spinnerets cream.

Leg spination: femora and patellae: spineless; tibiae: I plv 5 rlv 4, II plv 4 rlv 4; metatarsi: I plv 4 rlv 4, II plv 4 rlv 4; tarsi: I plv 3 rlv 3, II plv 3 rlv 3.

Palpal femur with small bifid RFA, proximal branch sharply hook-shaped, distal branch tooth-like ( Figs 56, 58 ); tibia with small, simple triangular apophysis; retrodistal tegular ridge strongly developed, curving around ventrally to base of embolus ( Fig. 57 ); embolus narrow, undulating slightly, with weak curve at half its length ( Fig. 57 ).

Type material. Holotype ♀ and paratype ♂: ETHIOPIA: Oromiya: 51 km E of Addis Ababa [ca. 09°00’N, 39°20’E], 18.VI.1988, leg. A. Russell-Smith (under stones, dry hillside) ( BMNH).

Paratypes: ETHIOPIA: Amhara: Bahir Dar, Lake Tana , 12°00’N, 37°20’E, XII.1973, leg. G. de Rougemont, 1♂ ( MRAC 158945 ) ; Oromiya: 17 km E of Addis Ababa [ca. 09°05’N, 39°05’E], 28.V.1988, leg. A. Russell-Smith (under stones, stream valley), 1♂ 2♀ ( BMNH) .

Habitat and biology. A ground-dwelling species sampled from under rocks in grassy savanna habitats.

Distribution. Only known from central Ethiopia ( Fig. 82 ).

Figures

FIGURE 82. Distribution of Orthobula aethiopica sp. nov. (circles), O. arca sp. nov. (squares) and O. calceata Simon, 1897 (triangles) in the continental Afrotropical Region.

FIGURES 1–12. Dorsal habitus photographs of Orthobula species: 1. O. aethiopica sp. nov., female; 2. Same, male; 3. O. arca sp. nov., female; 4. Same, male; 5. O. calceata Simon, 1897, female; 6. Same, male; 7. O. marusiki sp. nov., female; 8. Same, male; 9. O. milloti Caporiacco, 1949, female; 10. Same, male; 11. O. radiata Simon, 1897, female; 12. Same, male. Scale bars: 1 mm.

FIGURES 54–58. Orthobula aethiopica sp. nov., genitalic morphology of holotype female (54, 55) and paratype male (56–58) from Addis Ababa: epigyne, ventral (54) and dorsal (55) views; palp, prolateral (56), ventral (57) and retrolateral (58) views. Scale bars: 0.10 mm. Abbreviations: AG—accessory gland; BU—bursa; CD—copulatory duct; CO—copulatory opening; EM—embolus; FD—fertilisation duct; RFA—retrodistal femoral apophysis; RTA—retrolateral tibial apophysis; SBB—sclerotised base of bursa; ST I—primary spermathecae.

FIGURES 90–95. Orthobula milloti Caporiacco, 1949, genitalic morphology of female from Nairobi (90, 91) and male from Pugu (92–95): epigyne, ventral (90) and dorsal (91) views; right palpal tegulum, retrolateral (92), ventral (93) and prolateral (94) views; left palpal femur, patella and tibia, retrolateral view. Scale bars: 0.10 mm.

FIGURES 65–69. Orthobula calceata Simon, 1897, genitalic morphology of female (65, 66) and male (67–69) from Bagoé: epigyne, ventral (65) and dorsal (66) views; palp, prolateral (67), ventral (68) and retrolateral (69) views. Scale bars: 0.10 mm.