Ariadna clavata, Marsh, Jessica R., Baehr, Barbara C., Glatz, Richard V. & Framenau, Volker W., 2018

Marsh, Jessica R., Baehr, Barbara C., Glatz, Richard V. & Framenau, Volker W., 2018, New species of tube web spiders of the genus Ariadna from South Australia (Araneae, Segestriidae), Evolutionary Systematics 2 (2), pp. 137-149 : 137

Ariadna clavata sp. n. Figs 1 A–I, 2 A–H, 3 A–C, 8

Type material.

AUSTRALIA: South Australia: Holotype: ♂, Tangara Drive, American River, Kangaroo Island, - 35.787329S, 137.767213E, 3 June 2017, under bark at 1.5 m height, Eucalyptus diversifolia (1 m diameter), J. Marsh (SAM NN29861). Paratypes: 1♀, same data as holotype, except 8 July 2017, observed mating with holotype male in captivity, J. Marsh (SAM NN29862); 1♂, Pelican Lagoon walking trail, American River, Kangaroo Island, - 35.796496S, 137.750963E, 2 Nov 2017, under bark E. diversifolia , J. Marsh (CeNak ZMH-A0003051); 1♀, Tangara Drive, American River, Kangaroo Island, - 35.782887S, 137.771559E, 16 Aug 2017, in tube web at 1 m height, in crevice of bark of Allocasuarina muelleriana , J. Marsh (CeNak ZMH-A0003052).

Other material examined.

AUSTRALIA: South Australia: Kangaroo Island: 1♂, Cannery walking trail, American River, - 35.773707S, 137.781111E, 16 Aug 2017 (SAM NN29879); 1♀, Pelican Lagoon Walking Trail, American River, - 35.792580S, 137.757909E, 1 Sept 2017 (SAM NN29876); 2♂, same data, except 10 Oct 2017 (SAM NN29881; J. Marsh reference collection, Se092); 4♂, 1♀ same data, except - 35.796496S, 137.750963E, 2 Nov 2017 (SAM NN29897, NN29899; J. Marsh reference collection, Se058); 1♂, Tangara Drive, American River, - 35.787181S, 137.766994E, 2 June 2017 (SAM NN29865); 1♂, same data, except 3 Jun 2017 (SAM NN29866); 1♂, same data, except 12 Jun 2017 (SAM NN29870); 1♂, 3♀, Antechamber Bay, Chapman River, - 35.790736S, 138.065559E, 1 Sept 2017 (SAM NN29892); 2♂, Baudin Conservation Park, Dudley Peninsula, - 35.734848S, 137.959212E, 15 Jul 2017 (SAM NN29908); 1♀, Dudley Conservation Park, Dudley West, - 35.795318S, 137.850007E, 22 Jun 2017 (SAM NN29911); 1♀, same data, except - 35.795452S, 137.860189E (SAM NN29872); 1♂, same data, except - 35.795946S, 137.860794E (SAM NN29868); 1♀, Pelican Lagoon Conservation Park, Dudley West, - 35.801685S, 137.774214E, 13 Oct 2017 (SAM NN29886); 3♂, 3♀, Simpson Road, Dudley West, - 35.823523S, 137.831032E, (SAM NN29910); 2♀, Three Chain Road, MacGillivray, - 35.910674S, 137.550490E, 26 Jul 2017 (SAM NN29909, NN29874); 4♀, same data, except 7 Aug 2017 (SAM NN29888, NN29889, NN29890); 4♀, roadside, near Parndana Conservation Park, - 35.757187S, 137.307314E, 17 Aug 2017 (SAM NN29891); 1♂, 2♀ roadside, near Parndana Conservation Park, - 35.757621S 137.307326E, 10 Aug 2017 (SAM NN29883); 1♀, same data, except - 35.756707S, 137.306523E (NN29895); 1♂, same data, except -35.757047S, 137.307237E (SAM NN29893); 1♂, same data, except - 35.757131S, 137.307199E (SAM NN29880). Mount Lofty Ranges: 1♂, 1♀, Devils Gully Native Forest Reserve, Kersbrook, - 34.7555556S, 138.818889E, Oct/ Nov 2000 (SAM, not accessioned); 1♂, Sixth Creek Native Forest Reserve, Forest Range, - 34.9002778S, 138.794167E, Oct/ Nov 2000 (SAM, not accessioned). Fleurieu Peninsula: 3♂, 2♀, Spring Mount, - 35.432222S, 138.523889E Dec/ Jan 2006 (SAM, not accessioned).

Etymology.

The specific epithet is an adjective (Latin, clavata - striped) referring to the striped abdominal markings of both the male and female.

Diagnosis.

Males and females of A. clavata sp. n. are distinguished from A. segmentata by the curvature of the posterior eye row, which is strongly procurved in A. segmentata (Hickman, 1967, fig. 63) and which is slightly recurved in A. clavata (Fig. 2C). Males of A. clavata differ from A. segmentata by the long, curved and distally hooked embolus (Fig. 1G, I), while the embolus of A. segmentata is shorter and stouter ( Hickman 1967, fig. 65). The pedipalp bulb of A. clavata differs from that of A. muscosa by being roughly pyramidal in shape, while that of A. muscosa is spheroidal (Fig. 1G, I; Hickman 1929, fig. 3a). Males and females of A. clavata differ from A. muscosa by the number of teeth on the tarsal claws of the first legs; A. muscosa has 7 or 8 teeth, with the inferior claw bare, A. clavata has 10 or 11 teeth, with a small tooth on the inferior claw (Fig. 2G). Females of A. clavata differ from A. burchelli by the number of teeth on the chelicerae; A. burchelli has one tooth either side of the fang furrow, A. clavata has three teeth on the promargin, one tooth on the retromargin (Fig. 2B, C). Ariadna clavata differs from all remaining Australian Ariadna by the presence of transverse abdominal markings (Fig. 1A).

Description.

Male holotype (SAM NN29861). Carapace length 3.5 mm, dark reddish brown, becoming darker anteriorly, covered with sparse dark setae; sternum brownish yellow, darker at the edges and between coxae; endites dark brown, chelicerae dark brown to black; legs yellowish brown; abdomen length 3.9 mm, dorsally pale yellow with 8 dark transverse bands, connected by triangular extensions at the midpoint (Fig. 1A), ventrally uniform yellow/grey (Fig. 1B). Carapace oval, narrowing anteriorly and apically square; raised anteriorly, highest just behind posterior eye row; lateral margins slightly undulating (Fig. 1A). Fovea an indented pit, with faint dark radial striae extending outwards from fovea. Labium narrowing anteriorly, ¾ the length of maxillae. Chelicerae semi-porrect, with strong lateral ridges dorsally and with basal transverse ridges (Fig. 1C), retromargin with single tooth, promargin with three teeth. Sternum oval with precoxal triangles and with small, rounder intercoxal extensions (Fig. 1B). Posterior eye row slightly recurved (Fig. 1C). Femur I bowed in dorsal view (Fig. 1D). Leg measurements ( I–IV): femora 2.74, 2.65, 2.06, 2.28; patellae 1.13, 1.16, 0.99, 1.06; tibiae 2.34, 2.53, 1.50, 1.76; tarsi 2.14, 2.29, 1.64, 1.72; metatarsi 0.97, 0.85, 0.79, 0.80; total 9.32, 9.48, 6.98, 7.62. Spines: Leg I: femur d1-1-1-1, dp2ap (Fig. 1D); tibia dp1-1, p1-1, vp1-1, vp1ap, v1, vr1-1/0-1/0, vr1ap, dv1-1/0; metatarsus vp1-1, vp1ap, v1, vr1-1, vr1ap. Leg II: femur d1-1-1-1-1/0, dp1ap; tibia dp1-1-1, p1, vp1ap, vr1-1-1/0, vr1ap; metatarsus vp1-1, vp1ap, v1, v1ap, vr1-1, vr1ap. Leg IV: femur d1-1-1-1/0, dp1ap, tibia dp1-1/0, vp1, vp1ap, vr1-1, vr1ap, dr1-1; metatarsus dp1, v1, vr1-1, vr2ap, r1-1, retrolateral distal preening comb with five spines (Fig. 1E). Legs I and II tarsal claws with 10 or 11 teeth, one small tooth on inferior claw (Fig. 1F). Legs III and IV tarsal claw with six teeth and inferior claw bare. Tarsi with distal ventral setae, projecting beneath claws (Fig. 1F). Pedipalp femur expanded apically, on the ventral retrolateral edge, so it appears slightly concave ventrally. Pedipalp tibia short, about 1.5 times as long as the cymbium, and swollen in the dorso-ventral plane (Fig. 1G, I). Bulb roughly pyramidal with embolus arising from the ventral point of the pyramid. Embolus long, thin, hooked apically (Fig. 1 G–I).

Female paratype (SAM NN29862). Carapace length 3.8 mm, brown, sternum light brown, with darker patches between coxae; endites yellowish brown, chelicerae brown; legs light brown. Abdomen length 4.6 mm, dorsally pale yellow with 8 dark transverse bands, connected by triangular extensions at the midpoint (Fig. 2A). Abdomen ventrally yellowish grey with faint longitudinal darker line centrally (Fig. 2B). Carapace dorsal surface sparsely covered with black setae, with stronger and longer black setae projecting forward from the clypeus (Fig. 2C). Carapace elongated and oval, narrowing anteriorly and apically squared; carapace domed so when viewed laterally highest point is mid-way between fovea and posterior eyes; lateral margin of carapace slightly undulating, fovea a shallow indented pit (Fig. 2A). Sternum oval with precoxal triangles and small, rounder inter-coxal extensions (Fig. 2B). Labium narrowing anteriorly, about ¾ length of maxillae. Posterior eye row slightly recurved, chelicerae hypognathous, covered in strong, long black setae and with basal transverse ridges (Fig. 2C), retromargin with single tooth, promargin with three teeth. Femur I bowed in dorsal view (Fig. 2A, E). Leg measurements ( I–IV): femora 2.83, 2.59, 1.96, 2.23; patellae 1.21, 1.26, 1.03, 1.25; tibiae 2.08, 2.16, 1.41, 1.8; metatarsi 1.66, 1.76, 1.31, 1.52; tarsi 0.84, 0.89, 0.75, 0.76; total 8.62, 8.67, 6.46, 7.55. Spines: Leg I: femur dp2ap (Fig. 2E); tibia vp1-1-1, vp1ap, v1, vr1-1, vr1ap, v1/0; metatarsus vp1-1-1, vp1ap, v1, v1ap, vr1-1, vr1ap (Fig. 2 D–F). Leg II: femur dp1ap; tibia p1, vp1ap, v1-1, v1ap; metatarsus vp1-1-1, vp1ap, v1, v1ap, vr1-1-1/0, vr1ap. Leg IV: femur d1-1, dp1ap, tibia p1, vp1ap, v1, vr1-1, vr1ap; metatarsus v1, vr1-1, vr2ap (1 spine broken), distal retrolateral preening comb with five spines (Fig. 2H). Tarsi with distal ventral hairs, projecting beneath claws, tarsal claws I and II with 11/12 teeth, inferior claw with one small tooth (Fig. 2G). Legs III and IV tarsal claw with six teeth, inferior claw bare. Pedipalps with multiple strong prolateral spines on the tarsus and tibia, and with a single toothless claw. Epigastrium a slightly raised, lightly sclerotized external plate. Internal genitalia: Anterior receptaculum bilobed, dorsal lobe rounded and about 1.5 times as long as ventral lobe. Fig. 3 A–C.

Variation

(see Suppl. material 1: Table S1): Males (n=21), carapace length: range 2.46-3.64 mm, mean 3.14 mm, standard deviation 0.38 mm. Females (n=23), carapace length: range 2.57-4.34 mm, mean 3.63 mm, standard deviation 0.47 mm. Whilst leg spination showed a large amount of variation, both between and within specimens, some spines showed a higher level of consistency and this was true for both males and females e.g. (1) number of prolateral macrosetae at the apex of the femur I, and (2) the paired macrosetae at the apices of tibiae and metatarsi I and II. The remainder of the spination varied between specimens. The structure of the ‘preening’ combs on the metatarsus IV was constant in all specimens examined (Figs 1E, 2H).

Distribution.

South-eastern South Australia, including the Fleurieu Peninsula, the Mount Lofty Ranges and Kangaroo Island (Fig. 8).

Life history and habitat preferences.

The majority of A. clavata specimens were collected from within tube webs located beneath rugose bark of older Eucalyptus trees. Rather than tree species, the structure of the bark (with specimens found in older, cracked or layered bark), appeared to be of importance. The species appears to be somewhat opportunistic in terms of the location of its retreats, being a variety of holes and crevices, such as borer holes in dead wood (both as standing trees and in logs lying on the ground), in tubular holes in limestone and in burrows in loose soil beneath rocks. The main habitat type was mallee woodland. Specimens were also collected from isolated trees on roadside verges and from a stand of Pinus radiata near D’Estrees Bay (Kangaroo Island). Mature males were collected manually throughout autumn, winter and spring (March through to October). Mature females were present all year.