Africactenus unumus Sankaran & Sebastian 2018, sp. nov.
Creators: name: Sankaran, Pradeep M.
name: Sebastian, Pothalil A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Ctenidae
Africactenus
Africactenus unumus

description: Africactenus unumus sp. nov.
Figs 1A, 2A–B, 3, 4
Type material. Holotype, male missing right leg I (ADSH203 A) from Areeppara in Edappady, 9o42'35.62''N, 76o42'48.42''E, Kottayam, Kerala, India, 27 m alt., 28 July 2013, M.S. Pradeep leg., from ground, by hand. Paratype, male (ADSH203 B), same data as holotype, except 20 August 2014.
Additional material examined. INDIA, Kerala: Pathanamthitta, Thiruvalla, Kavumbhagom, 9o24'15.60''N, 76o32'45.36''E, 3 m alt., 1 male (ADSH203 C), Sam Thomas leg., 19 June 2013, from ground, by hand.
Diagnosis. Males of Africactenus unumus sp. nov. seem closely similar to the males of Africactenus decorosus (Arts, 1912) as both share the wide, transversely oriented apical part of embolus as well as the same position and orientation of the conductor, but can be separated from the latter by the following combination of characters: RTA with single inferior denticle (RTA of A. decorosus with three inferior denticles), broad conductor (A. decorosus with thin conductor), MA lying away from embolus (MA of A. decorosus lying close to embolus), embolus with embolic apophysis (embolus of A. decorosus lacks embolic apophysis) and embolus narrowing at tip (A. decorosus with uniformly wide embolus) (Fig. 3A–C, compare with Steyn et al. 2003: figs 7–8).
Description. Male (holotype, Figs 1A, 2A–B). Carapace with deep median indentation (Fig. 2A), brownish, with faint, blackish, reticulated pattern and mats of greyish hairs along sides, with broad, median, pale brown, roughly flower vase-like patch, its posterior part just in front of fovea abruptly narrowing towards pedicel, its apical part with a longitudinal white stripe, which bifurcates posteriorly to continue along lateral margins (Fig. 1A). Fovea long (1.39), longitudinal, black. Eye field, clypeus, chelicerae, labium, endites, sternum, spinnerets, and legs brownish. Clypeus very high (Fig. 2B). Chelicerae dorsally with greyish-brown stiff hairs; promargin with a thick layer of long, brownish, inwardly curved hairs, with one teeth and two denticles, retromargin with four teeth and two small denticles. Fangs black. Sternum clothed with black hairs. Opisthosoma elongated oval, olive-brown, with irregularly scattered black spots and striae; dorsum medially with a broad longitudinal, straw-coloured patch, anterior 2/3rd of which medially possesses a pale yellowish band; dorsum with scattered clusters of white, stiff hairs (Fig. 1A); venter medially with a broad yellowish patch, the middle of which bears a longitudinal olive-brown stripe. Scopulae on tarsi entire; scopulae on metatarsi I–II entire, 2/3rd of metatarsus III with reduced scopula, metatarsus IV lacks scopula. Body length 14.99. Carapace length 7.98, width 6.71. Opisthosoma length 7.01, width 3.98. Eye diameters: ALE 0.24. AME 0.36. PLE 0.53. PME 0.44. Eye interdistances: ALE–ALE 1.46. ALE–PME 0.19. AME–ALE 0.30. AME–AME 0.25. PLE–PLE 1.72. PME–PME 0.36. Clypeus height at AMEs 0.71, at ALEs 1.29. Chelicerae length 3.79. Measurements of pedipalp and legs: pedipalp 12.97 [5.05, 1.85, 2.87, 3.20], I 51.44 [13.82, 4.17, 15.39, 14.25, 3.81], II 45.77 [12.38, 4.11, 13.19, 12.65, 3.44], III 36.71 [10.22, 3.22, 10.12, 10.41, 2.74], IV 53.19 [14.83, 3.34, 13.47, 18.03, 3.52]. Leg formula: 4123. Spination of pedipalp: femur pld 1 do 4 rld 1, patella pl 1 rl 1, tibia pl 1 plv 1 rl 1 rld 1, tarsus/cymbium spineless; legs: femur I pl 2 pld 2 plv 1 do 1 rld 4, II pl 1 pld 3 do 3 rld 4, III–IV pld 4 do 3 rld 4; patellae I–IV pl 1 rl 1; tibiae I–II pl 1 plv 6 do 4 rl 2 rlv 6, III pl 2 plv 3 do 3 rl 1 rld 1 rlv 3, IV pl 2 plv 3 do 4 rl 2 rlv 3; metatarsus I pl 1 plv 2 rl 2 rlv 3, II pl 1 plv 3 rl 2 rlv 3, III pl 1 pld 3 plv 3 rl 1 rld 3 rlv 3, IV pl 1 pld 4 plv 4 rl 2 rld 3 rlv 4; tarsi I–IV spineless. Pedipalp (Fig. 3A–C): palpal segments brownish with faint black annulations on femur, patella and tibia. RTA short with broad base and one tiny, sharp inferior denticle (Fig. 3B, arrow). Ventro-lateral tibial apophysis short, thumb-like, directed at 2-o’clock in ventral view (Fig. 3B). Distal part of cymbium slender, cylindriform; cymbium with a short baso-retrolateral, lamella-like outgrowth (Fig. 3B–C). Tegulum nearly oval. Subtegulum small. MA nearly globular, medio-retrolateral (Fig. 3B). Embolus long, with well sclerotised median part over membranous part, with wide, transversely oriented apical part, with hook-like tip, with a short, flat apophysis (Fig. 3A–B). Conductor broad, hyaline, apico-retrolateral, anterior part slightly overlying the embolar tip (Fig. 3B–C).
Female: Unknown.
Etymology. The specific epithet, from the Latin unum = one, is an adjective and refers to the single inferior denticle of the RTA of the new species.
Variation. Males (n=3): body length 10.87–14.99.
Distribution. India (Kerala) (Fig. 4).
description: Published as part of Sankaran, Pradeep M. & Sebastian, Pothalil A., 2018, First record of Africactenus Hyatt, 1954 and redescriptions of two poorly known species of Ctenus Walckenaer, 1805 (Araneae, Ctenidae, Cteninae) from India, pp. 395-406 in Zootaxa 4388 (3) on pages 396-399, DOI: 10.11646/zootaxa.4388.3.5, http://zenodo.org/record/1188688