Ariadna subnubilum Marsh & Stevens & Framenau 2022, sp. nov.
Creators: name: Marsh, Jessica R.
name: Stevens, Mark I.
name: Framenau, Volker W.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Segestriidae
Ariadna
Ariadna subnubilum

description: Ariadna subnubilum sp. nov. (TMAG J6266)
Figs 31a–h, 32a–c, 33
http://zoobank.org/NomenclaturalActs/485dae32-c304-4f07-9290-bf7860d29343
Type material. Holotype ♂. AUSTRALIA: Tasmania: 5km ENE McPartlan Pass, 42.83796°S, 146.24072°E, 350m, February 2002, pitfall trap, coll. D. Driscoll (TMAG J6266).
Other material examined. Known only from the type specimen.
Etymology. The specific epithet is a Latin adjective, meaning ‘somewhat overcast’ and refers to the mottled light and dark grey colour of the species’ abdomen.
Diagnosis. Ariadna subnubilum sp. nov. is most similar to A. crypticola sp. nov., A. ferrogrisea sp. nov. and A. muscosa. Ariadna subnubilum sp. nov. is differentiated from A. crypticola sp. nov. by having a squarer cymbium, with a less well defined prolateral extension than in A. crypticola sp. nov. (Fig. 32c cf. Fig. 14c), and by the lack of a transverse abdominal pattern (Fig. 31a cf. Fig. 13a). It can be differentiated from A. ferrogrisea sp. nov. by the pattern and number of macrosetae on tibia and metatarsus of leg I, which are denser in A. ferrogrisea sp. nov. (Fig. 31 f-h cf. Fig. 15f–h), by the lack of transverse abdominal markings in A. subnubilum sp. nov. (Fig. 31a cf. Fig. 15a) and by the shape of the pedipalp bulb, which is pyramidal in A. ferrogrisea sp. nov., but is rounded oblong in A. subnubilum sp. nov. (Fig. 32a, b cf. Fig. 16a, b). The species can be distinguished from A. muscosa by the lack of transverse abdominal markings in A. subnubilum sp. nov. (Fig. 31a cf. Fig. 24a); by the greater width compared to length of the pedipalp tibia of A. subnubilum sp. nov. (Fig. 32a, b cf. Fig. 25a, b) and molecular sequencing, with an interspecies divergence of 11.6% (Table 2).
Description. ♂ (based on holotype; TMAG J6266). Total length 4.6.
Colour in ethanol: Carapace dark red brown, darker anteriorly; with sparse, scattered dark setae, denser anteriorly. Sternum mid red brown, with black long brown setae. Maxillae and labium mid brown, paler in colour apically; chelicerae dark red brown. Abdomen dorsally light grey with mottled darker grey patches; ventrally same. Legs golden yellow brown, with dark setae (Fig. 31a–h).
Cephalothorax: 2.4 long, 1.6 wide. Carapace broadly oval, anteriorly with broad neck, caput raised towards anterior, fovea shallow (Fig. 31a); in lateral view highest at midpoint between fovea and eyes (Fig. 31c). Labium narrowed anteriorly, about ¾ length of maxillae; chelicerae semi-porrect, with basal transverse ridge, retromargin with single tooth, promargin with three teeth; sternum rounded oval, with precoxal triangles and with smaller, rounded intercoxal extensions (Fig. 31b). Posterior eye row slightly recurved, eye group on prominent extension projecting anteriorly over clypeus, eye group occupying 0.6 of carapace width.
Abdomen: 2.2 long; with a covering of dense, fine setae (Fig. 31a)
Legs: Leg length ratio: I>II>IV>III. Leg I femur 2.4, patella 0.8, tibia 2.1, metatarsus 2.1, tarsus 0.9. Leg II femur 2.2, patella 0.7, tibia 2.2, metatarsus 1.9, tarsus 1.0. Leg III femur 1.5, patella 0.5, tibia 1.5, metatarsus 1.4, tarsus 0.7. Leg IV femur 2.0, patella 0.6, tibia 1.5, metatarsus 1.4, tarsus 0.6. Leg I Femur I bowed in dorsal view. Macrosetae: leg I femur d1-1-1-1ap, dp2ap; tibia p1-1-1-1-1, pv1-1-1-1-1ap, v1-1-1-1, rv1-1-1-1-1ap, r1-1-1-1-1-1; metatarsus pv1-1-1-1-1-1ap, rv1-1-1-1, r1. Leg II femur d1-1-1-1ap, dp1ap; tibia pv1-1-1, v1-1-1ap, rv1-1-1-1-1- 1-1-1-1ap, r1-1-1-1-1; metatarsus p1, pv1-1-1-1-1-1ap, rv1-1-1-2ap, r1. Leg IV femur d1-1-1-1, dp1ap; tibia p1-1, pv1-1-1ap, rv1-1; metatarsus p1, rv1-1-1-1ap, r1. Retrolateral distal preening comb with 7 spines (Fig. 31e). STC I, II with 9 long teeth, ITC with single tooth, Tarsi with sparse distal ventral scopulose setae.
Pedipalp: Tibia short, bulbous and ventrally expanded, about 1 1/2 the length of the cymbium; cymbium rounded square, with prolateral triangular extension, apically with elongate setae; bulb rounded oblong, embolus originating from ventral edge of bulb, quite broad, curved and hooked apically (Fig. 32a–c).
Variation. Known only from the type specimen.
Distribution. Known only from McPartlan Pass, northwest Tasmania (Fig. 33).
DNA barcode. A 655 base-pair (bp) fragment of the mitochondrial (mt) DNA cytochrome c oxidase I (COI) gene (DNA barcode) was sequenced for specimen TMAG J6266 (see Holotype information above) and is deposited in BOLD (Process ID OZBOL2584-21) and GenBank (accession number ####). The base composition of the DNA barcode sequence is 21.07% A, 40.15% T, 13.59% C and 25.19% G (G + C = 38.78%).
description: Published as part of Marsh, Jessica R., Stevens, Mark I. & Framenau, Volker W., 2022, A taxonomic revision of the tube-web spiders of the genus Ariadna (Araneae: Segestriidae) in Tasmania, pp. 151-201 in Zootaxa 5105 (2) on pages 186-189, DOI: 10.11646/zootaxa.5105.2.1, http://zenodo.org/record/6332569