Orthobula milloti Caporiacco, 1949

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 : 374-375

Orthobula milloti Caporiacco, 1949

Figs 9, 10 , 90–95

Orthobula milloti Caporiacco, 1949: 441 , fig. 75a–c (♂ and ♀ syntypes: KENYA: Nairobi [01°15’S, 36°50’E], 1500 m a.s.l., 1944, leg. Toschi & Meneghetti, deposited in MSNVR—not examined).

Remark. Although we were unable to examine the syntypes of O. milloti , we were able to redescribe a topotypical female and match that to other specimens from East Africa, both males and females.

Diagnosis. Females of O. milloti share with those of O. aethiopica sp. nov. a broad, semicircular anterior ridge in the epigyne, but can be distinguished by the short copulatory ducts that are approximately equal in length to the width of the SBB ( Fig. 90 ), while twice as long as the width of SBB in O. aethiopica sp. nov. ( Fig. 54 ). Males of O. milloti most closely resemble those of O. radiata in the short, straight spike-like embolus, but can be distinguished by the shape of the RFA, which is simple and finger-like in O. milloti ( Fig. 95 ), while bifid in O. radiata ( Fig. 100 ).

Female (Nairobi, BMNH). Measurements: CL 1.15, CW 0.86, AL 1.04, AW 0.98, TL 2.52, PERW 0.24, MOQAW 0.10, MOQPW 0.13, MOQL 0.11. Length of leg segments: I 0.47 + 0.21 + 0.44 + 0.41 + 0.21 = 1.74; II 0.43 + 0.17 + 0.33 + 0.35 + 0.29 = 1.57; III 0.35 + 0.16 + 0.27 + 0.33 + 0.18 = 1.29; IV 0.48 + 0.18 + 0.42 + 0.47 + 0.22 = 1.77.

Colour: carapace dark brown, with faint black mottling; chelicerae dark brown; endites and labium dark brown, creamy-grey distally; sternum dark brown, margins slightly darker; palps brown, distal ends of segments with yellow rings; legs with femora, patellae and tibiae I and II brown, of III and IV yellow-brown, all with black mottling laterally; distal ends of femora and tibiae, and basal end of patellae, with yellow rings; metatarsi yellow-brown, with faint mottling; tarsi yellow; abdomen black dorsally, with pair of cream longitudinal patches anterolaterally and transverse cream band at midpoint; venter creamy-grey; spinnerets cream.

Leg spination: femora and patellae: spineless; tibiae: I plv 6 rlv 6, II plv 5 rlv 5; 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. 90 ); CD very short, initially directed mesally, curving sharply before entering round SBB at centre of epigyne; CO separated by approximately SBB diameter, SBB separated by approximately ¼ their width; CD approximately as long as SBB width; BU ovoid, almost round, with teardrop-shaped accessory gland on their anteromesal surface; SBB connected to ST I by short looping longitudinal ducts, entering transversely oval ST I on their mesal surface; ST I almost touching along their mesal surfaces ( Fig. 91 ).

Male (Pugu Forest Reserve, MRAC 159243). Measurements: CL 0.81, CW 0.66, AL 0.83, AW 0.65, TL 1.64, PERW 0.32, MOQAW 0.12, MOQPW 0.16, MOQL 0.14. Length of leg segments: I 0.62 + 0.24 + 0.53 + 0.49 + 0.27 = 2.15; II 0.54 + 0.21 + 0.42 + 0.42 + 0.27 = 1.86; III 0.43 + 0.19 + 0.33 + 0.39 + 0.26 = 1.60; IV 0.57 + 0.21 + 0.49 + 0.57 + 0.31 = 2.15.

Colour: carapace deep brown, pits with darker edges, lateral margins black; chelicerae brown, with faint black mottling; endites and labium brown, lighter distally; sternum orange-brown, with sparse mottling, margins darker; palps yellow-brown; legs yellow-brown, anterior femora darker; all femora, patellae and tibiae with distal mottled patches laterally; abdomen black, with pair of dark yellow-brown oval anterolateral markings; venter brown, with dense black mottling laterally, epigastric plate deep brown; spinnerets yellow-brown.

Leg spination: femora and patellae: spineless; tibiae: I plv 5 rlv 5, II plv 5 rlv 4; metatarsi: I plv 4 rlv 4, II plv 4 rlv 4; tarsi: I plv 3 rlv 3, II plv 3 rlv 2.

Palpal femur with curved, finger-like RFA ( Fig. 95 ); tibia with small, simple triangular RTA; retrodistal tegular ridge short, not curving around ventrally to base of embolus ( Fig. 92 ) embolus short, straight, spike-like ( Figs 92–94 ).

Material examined. KENYA: Nairobi, grounds of National Museum [01°16’S, 36°48’E], 12.IV.1988, leg. A. Russell-Smith (in tall grass), 1♀ ( BMNH) . TANZANIA: Pwani Region: Kisarawe district, Pugu Forest Reserve , 09°59’S, 39°07’E, 11.XI.1979, leg. K.M. Howell, 1♂ ( MRAC 159243 ) . Lindi Region: Lindi District, Litipo Forest Reserve , 10°02’S, 39°29’E, VII–IX.1993, leg. Frontier Tanzania, 1♀ ( ZMUC) . Tanga Region: Mlola, Mafia , 07°53’S, 39°50’E, X–XI.1990, leg. Frontier Tanzania (evergreen coastal thicket on clay, coral rag), 2♂ ( ZMUC) .

Habitat and biology. A rare ground-dwelling spider sampled in urban natural habitat fragments, and forest and savanna habitats.

Distribution. Only known from western Kenya and eastern Tanzania ( Fig. 101 ).

Figures

FIGURE 101. Distribution of Orthobula marusiki sp. nov. (circles), O. milloti Caporiacco, 1949 (squares), O. radiata Simon, 1897 (triangles) and unidentified Orthobula species (red 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 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 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 96–100. Orthobula radiata Simon, 1897, genitalic morphology of female (96, 97) and male (98–100) from Ndumo: epigyne, ventral (96) and dorsal (97) views; palp, prolateral (98), ventral (99) and retrolateral (100) views. Scale bars: 0.10 mm.