Ariadna fragilis 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 fragilis

description: Ariadna fragilis sp. nov.
Figs 20a–h, 21a–c, 19
http://zoobank.org/NomenclaturalActs/4fecfd82-2de9-4643-a792-a8938643c7d6
Type material. Holotype ♂. AUSTRALIA: Tasmania: Mount Chappell Island in Bass Strait, 40.27°S, 147.52°E, 29 July 1989 – 7 August 1989, coll. S. Fearn (QVMAG QVM:2020:13:0111)
Other material examined. Known only from the type specimen.
Etymology. The specific epithet is a Latin adjective meaning ‘fragile’ and refers to the slender form of the species.
Diagnosis. Ariadna fragilis sp. nov. is most similar to A. abbreviata sp. nov., A. clavata and A. tigrina sp. nov.. It is differentiated from A. abbreviata sp. nov. by the lack of shortened, blunt macrosetae prolaterally on metatarsus I (Fig. 20f–h cf. Fig. 1f–h). It is differentiated from A. clavata by its slenderer pedipalp tibia compared to the cymbium length and by the embolus, which is less hooked apically in A. fragilis sp. nov., than in A. clavata (Fig. 21a, b cf. fig. 1g, i Marsh et al. 2018). The species is differentiated from A. tigrina sp. nov. by its longer and slenderer pedipalp tibia (Fig. 21a, b cf. Fig. 39a, b), and by the pattern of macrosetae on the tibia and metatarsus of leg I, which is paired in A. fragilis sp. nov. (Fig. 20f–h cf. Fig. 37f–h).
Description. ♂ (based on holotype; QVMAG QVM:2020:13:0111). Total length 4.7.
Colour in ethanol: Carapace golden, orange brown, sparse, scattered light setae, caput area raised anterior to fovea and lighter yellow brown; sternum yellow brown, with sparse long brown setae, maxillae yellow brown, paler in colour apically, labium darker orange brown, chelicerae orange brown; abdomen dorsally pale grey, with nine dark grey, clearly defined chevrons, with triangular extensions in the centre and joined by dark median line, ventrally cream with dark patches centrally and laterally. Legs yellow brown, with darkened patches distally tibiae I and II, with sparse brown setae (Fig. 20a–c).
Cephalothorax: 2.2 long, 1.4 wide. Carapace oval, blunt anteriorly, caput raised towards anterior, highest at eyes, fovea shallow (Fig. 20a); in lateral view carapace projected forward over clypeus (Fig. 20c). Labium narrowed anteriorly, about ¾ length of maxillae; chelicerae with basal transverse ridge, retromargin with single tooth, promargin with three teeth; sternum oval, domed with precoxal triangles and with smaller, rounded intercoxal extensions (Fig. 20b). Posterior eye row straight, eye group occupying about a third of carapace width (Fig. 20d).
Abdomen: 2.5 long. Covered in fine dense setae (Fig. 20a).
Legs: Leg length ratio: I>II>IV>III. Leg I femur 1.2, patella 0.4, tibia 1.5, metatarsus 1.3, tarsus 0.5. Leg II femur 0.9, patella 0.4, tibia 1.4, metatarsus 1.2, tarsus 0.6. Leg III femur 1.1, patella 0.5, tibia 0.9, metatarsus 0.6, tarsus 0.4. Leg IV femur 1.3, patella 0.5, tibia 1.2, metatarsus 0.7, tarsus 0.4. Femur I bowed in dorsal view. Macrosetae: Leg I: femur dp2ap; tibia p1, pv1-1-1 (long)-1ap, rv1-1-1ap; metatarsus pv1-1-1, rv1-1-1-1ap. Leg II femur dp1ap; tibia dp1-1-2, dp1ap, v1-1-1ap; metatarsus pv1-1-1-1ap, v1, rv1-1-1-1/0ap. Leg IV tibia v1-1; metatarsus r1- 1-1ap, rv1. Retrolateral distal preening comb with 6 spines (Fig. 20e). STC I, II with 11 long teeth, ITC with single long tooth, Tarsi with distal ventral scopulose setae.
Pedipalp tibia short, about 1 ½ the length of the cymbium; cymbium rounded square shape, with anterior prolateral extension; bulb pyramidal in lateral view, embolus elongate, thin and hooked apically (Fig. 21a–c).
Variation. Known only from the type specimen.
Distribution. Known only from type locality, Mount Chappell Island in the Furneaux Group (Fig. 19).
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 174-175, DOI: 10.11646/zootaxa.5105.2.1, http://zenodo.org/record/6332569