Shearella alii, Sankaran & Sebastian, 2016

Sankaran, Pradeep M. & Sebastian, Pothalil A., 2016, A checklist of Indian armored spiders (Araneae, Tetrablemmidae) with the description of a new species from the Western Ghats, Zootaxa 4084 (3), pp. 443-450 : 444-446

Shearella alii sp. nov.

( Figs 1A–B , 2A–F , 3A–D )

Type material: Holotype: Male ( ADSH 100261 ), INDIA: Kerala: Thrissur, Chimmony Wildlife Sanctuary , 10o26'00.30''N, 76o28'56.41''E, 67 m. alt. , 31 May 2013, M.S. Pradeep leg., from forest litter, by hand; Paratypes: 2 males, 3 females ( ADSH 100262 ), same data as for holotype .

Diagnosis. S. alii sp. nov. is most similar to S. lilawati but can be distinguished by the following combination of characters: Males: Eye tubercle with pointed apex (eye tubercle in S. lilawati with blunt apex), triangular PLEs ( S. lilawati with circular PLEs), bulb with apple-like shape (in S. lilawati , bulb piriform), very long embolus (short embolus in S. lilawati ) and embolus with disto-prolateral origin (in S. lilawati , embolus originating apically). Females: 2 pairs of perigenital plates (1 pair in S. lilawati ), preanal plate with single row of pits and setae (in S. lilawati , preanal plate bearing numerous pits and setae in several irregular rows) and genital orifice situated in middle of epigastric fold (genital orifice in S. lilawati at posterior margin of epigastric fold) (compare figures 2A, C, 3A–D with Lehtinen 1981: figs 198A, 202, 203, 208 and 214).

Description. Male (holotype, figs 1A, 2A, C, 2E–F). Colouration: body brownish yellow; legs and palps yellowish brown. Prosoma finely retiform, with fine brownish streaks; cephalic region excluding the eye tubercle flat, thoracic margin rugose. Fovea indistinct. Ocular area black; six eyes in a compact group, ALE largest, PME smallest, raised on short, conical tubercle. Clypeus high, finely reticulated, slightly sloping forward. Chelicerae frontally with basally wide, pointed, upward-curving apophysis/horn ( Fig. 2E ). Sternum finely reticulated, with sparse setae, fused at margin with prosoma. Opisthosoma oval; dorsal scutum large, oval, glossy, densely pitted, covered with fine setae; lateral scuta glossy, with paired rows of pits accommodating backward-directed setae; lateral plate/sclerite IV long, narrower than plates/sclerites II and III; pulmonary plate glossy, with pits for setae; postgenital plate slightly overlapping anterior margin of preanal plate, narrower than preanal plate, laterally tapering, with median row of pits; preanal plate slightly longer and much wider than postgenital plate, with numerous pits; 2 pairs of perigenital plates, 1 pair on each side. Leg segments smooth, hirsute; leg I not modified; femora I–IV ventrally with a longitudinal row of granules; tibiae I–IV with 3 dorsal trichobothria each; metatarsi I– IV with 1 dorsal trichobothrium each. Body length 1.23. Prosoma length 0.45, width (in middle) 0.42, height (in middle) 0.25. Opisthosoma length 0.78, width (in middle) 0.66, height (in middle) 0.61. Eye diameters: ALE 0.06. PME 0.01. PLE 0.04. Distance between PLEs 0.04. Clypeus height at ALE 0.21. Length of chelicerae 0.19. Measurements of palp and legs: palp 1.07 [0.22, 0.12, 0.16, 0.57], I 1.36 [0.44, 0.13, 0.32, 0.24, 0.23], II 1.21 [0.38, 0.12, 0.28, 0.21, 0.22], III 1.10 [0.32, 0.12, 0.24, 0.21, 0.21], IV 1.42 [0.43, 0.13, 0.36, 0.27, 0.23]. Leg formula (from longest to shortest leg): 4123. Pedipalp ( Figs 3A–B ): Femur ventrally with a row of granules, without long setae (present in S. selvarani Lehtinen, 1981 and S. sanya ); tibia with 1 dorsal trichobothrium. Bulb broad, smooth, apple-like in appearance. Embolus very long (0.31), thin, originating disto-prolaterally to bulb, with broad base, curving inward, with wedge-shaped tip ( Fig 3A , see arrow). Spermophor long with broad basal part.

Female (paratype, figs 1B, 2B, D). In all details like male except for the following: Colouration: body dark brown. Eye tubercle low and domed. Chelicera without frontal apophysis/horn but with weak frontal protrusions ( Fig. 2D , see arrow). Lateral plate/sclerite IV nearly as wide as plates/sclerites II and III. Preanal plate with proximal row of pits. Body length 1.28. Prosoma length 0.49, width (in middle) 0.47, height (in middle) 0.29. Opisthosoma length 0.79, width (in middle) 0.69, height (in middle) 0.62. Eye diameters: ALE 0.04. PME 0.01. PLE 0.03. Distance between PLEs 0.05. Clypeus height at ALE 0.18. Length of chelicerae 0.19. Measurements of palp and legs: palp 0.24 [0.10, 0.03, 0.04, 0.07], I 1.24 [0.41, 0.12, 0.28, 0.20, 0.23], II 1.12 [0.34, 0.12, 0.25, 0.20, 0.21], III 1.02 [0.31, 0.12, 0.21, 0.19, 0.19], IV 1.34 [0.41, 0.12, 0.33, 0.26, 0.22]. Genitalia ( Figs 3C–D ): Epigastric fold distinct, strongly sclerotized, laterally with upward curving ends touching seminal receptacula. Genital orifice transversely oval, less obvious than surrounding dark region. Central genital process short, conical. Vulval stem broad, nearly triangular. Inner vulval plate finger-like, with blunt apex. Vulval ducts membranous originating antero-laterally from vulval stem, leading to sac-like seminal receptacula.

Variation. Male (n = 3): Body length 1.15–1.23. Female (n=3): Body length 1.22–1.28

Etymology. The specific epithet is a patronym honouring Dr. Salim Ali, the Birdman of India, one of the greatest ornithologists and naturalists in the world.

Natural history. Shearella alii sp. nov. inhabits the leaf litter layer in a dry deciduous forest.

Distribution. At present known only from the type locality ( Fig. 4 ). Remark. First record of the genus from India.

Figures

FIGURE 1. Shearella alii sp. nov. A Male holotype, dorsal view; B Female paratype, dorsal view. Scale bars: 0.5 mm.

FIGURE 2. Shearella alii sp. nov. A Male holotype habitus, retrolateral view; B Female paratype, habitus, retrolateral view; C Male, frontal view; D Female, frontal view; E Male, left chelicera, retrolateral view; F Male, left leg I, retrolateral view. Scale bars: A – B 0.15 mm; C, 0.08 mm; D, 0.06 mm; E, 0.02 mm; F, 0.40 mm.

FIGURE 3. Shearella alii sp. nov. A Male, left pedipalp, prolateral view; B Same, retrolateral view; C Female, opisthosoma, ventral view; D Female, genital area, dorsal view. Abbreviations: B bulb, CP central process, E embolus, EF epigastric fold, GO genital orifice, IVP inner vulval plate, PA preanal plate, PEG perigenital plate, POG postgenital plate, S spermophor, SR seminal receptacle, VS vulval stem. Scale bars: A – B 0.16 mm; C, 0.10 mm; D, 0.01 mm.

FIGURE 4. Map showing the currently known localities of Shearella spp. ● Shearella alii sp. nov. Shearella lilawati Lehtinen, 1981 ▲ Shearella sanya Lin & Li, 2010 ♦ Shearella selvarani Lehtinen, 1981.