Oecobius thar Tripathi & Sudhikumar & Sherwood 2023, sp. nov.
Creators: name: Tripathi, Rishikesh
name: Sudhikumar, Ambalaparambil V.
name: Sherwood, Danniella
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Oecobiidae
Oecobius
Oecobius thar

description: Oecobius thar sp. nov.
Figs 1–5
Etymology. The specific name refers to the Thar Desert, where this species lives, and is a noun in apposition.
Type material. Holotype ♂ (NRC-AA-4153), INDIA: Rajasthan, Jaisalmer, Thar Desert, Sam area (26.8303°N, 70.5085°E). 235 m a.s.l., found on wall, collected by hand, 14 Aug. 2022, R. Tripathi coll. Paratypes: same data as holotype, ♂ (NRC-AA-4154), ♀ (NRC-AA-4155).
Diagnosis. Oecobius thar sp. nov. most closely resembles O. cumbrecita Wunderlich, 1987, O. fortaleza Wunderlich, 1992 and O. infierno Wunderlich, 1987 by the curved OTL (Figs 2A–C, 3), however it can be distinguished by the apex of the OTL ending with three denticles (Figs 2B–C), which are absent in O. cumbrecita, O. fortaleza and O. infierno. Females of O. thar sp. nov. can be distinguished by the triangle-shaped and heavily sclerotised epigyne (Fig. 2D, not triangle-shaped in all other known congeners).
Description. Male holotype: Colour (in alcohol): carapace and dorsal and lateral faces of palp dark brown; legs beige, with black annulation on all segments; opisthosoma overall dark brown (darker than carapace), dorso-lateral outermost quarters mottled with white blotches, dorso-medial area with foliate pattern at posterior extent, spinnerets and ventral face of the opisthosoma dark brown (Fig. 1A–B). Total length 1.77. Carapace 0.75 long, 0.82 wide. Eyes: ALE 0.04, AME 0.06, PLE 0.08, PME 0.02, ALE–ALE 0.16, AME–AME 0.06, PLE–PLE 0.11, PME–PME 0.04. Opisthosoma 1.02 long, 0.68 wide. Legs: I 2.24 (0.68+0.13+0.50+0.51+0.42), II 2.51 (0.73+0.15+0.57+0.61 +0.45), III 2.55 (0.74+0.18+0.55+0.62+0.46), IV 2.69 (0.76+0.22+0.59+0.63+0.49). Palp: with massive oecobiid tegular lobe tapering strongly in proximal third, apex with three denticles, process present at base; embolus short; oecobiid tegular apophysis well-developed with two projections at apex, base with proximal process; membranous conductor present and rounded, anterior part of tegulum smooth and unmodified (Figs 2A–C, 3).
Female paratype: Colour (in alcohol): carapace dark brown; legs beige and non-annulated; opisthosoma overall beige, overlain with black setae, dorso-median aspect with foliate pattern and two parallel black blotches, spinnerets and ventral face of opisthosoma mouse brown (Fig. 1C–D). Total length 1.89. Carapace 0.66 long, 0.72 wide. Eyes: ALE 0.04, AME 0.06 PLE 0.07, PME 0.03, ALE–ALE 0.16, AME–AME 0.07, PLE–PLE 0.14, PME–PME 0.03. Opisthosoma 1.23 long, 0.79 wide. Legs: I 2.12 (0.67+0.14+0.48+0.43+0.40), II 2.36 (0.72+0.16+0.55+0.51+0.42), III 2.43 (0.75+0.19+0.51+0.57+0.41), IV 2.71 (0.71+0.22+0.63+0.75+0.40). Genitalia: epigyne triangle-shaped, sclerotised, with prominent proximal apex and widely spaced copulatory openings; copulatory atrium prominent, copulatory ducts twisted, each with an anterior diversion in the proximal third, copulatory ducts connecting at apex to asymmetrical globular spermathecae (Figs 2D–E). We were unable to observe any fertilisation ducts, although cannot rule out their presence.
Colour in vivo. Typically as found in the (freshly) preserved specimens, although both male (Fig. 4A–C) and female (Fig. 4D) are more vibrant in respective colours.
Natural history. Oecobius thar sp. nov. exhibited a habitat preference consistent with a synanthropic lifestyle (Fig. 4E). A large number of specimens were observed by RT on a residential wall, where female specimens constructed small sheet webs housing a cluster of eggs. They were observed to primarily predate ants and dipterans. During prey capture, the females employed a dynamic strategy, swiftly manoeuvring around their prey and utilizing a continuous silk-spinning technique to entrap and immobilize the target (RT pers. obs.). This behaviour is in no way unique, having been reported in several other congeners (Glatz 1967; Voss et al. 2007; García et al. 2014; Líznarová et al. 2013; Líznarová & Pekár 2015).
Distribution. Known only from the type locality, in the Thar Desert (Fig. 5).
description: Published as part of Tripathi, Rishikesh, Sudhikumar, Ambalaparambil V. & Sherwood, Danniella, 2023, A new species of Oecobius Lucas, 1846 from the Thar Desert, India (Araneae: Oecobiidae), pp. 483-490 in Zootaxa 5389 (4) on pages 485-488, DOI: 10.11646/zootaxa.5389.4.6, http://zenodo.org/record/10417362