Araneus strandiellus Charitonov, 1951

Marusik, Yuri M., Sestakova, Anna & Omelko, Mikhail M., 2012, First description of the male with redescription of the female of Araneus strandiellus Charitonov, 1951 (Araneae, Araneidae), ZooKeys 205, pp. 91-98 : 92-96

Araneus strandiellus Charitonov, 1951 Figs 1-14, 18-21

Araneus strandiellus Charitonov 1951: 210, f. 2a-b (♀).

Araneus strandiellus : Pavlenko 1985: 153; Marusik 1989: 41; Marusik et al. 1990: 17; Mikhailov 1997: 116; Araneus strandiellus : Logunov et al. 1998: 130; Marusik et al. 2000: 13.

Material examined.

Holotype ♀ (PSU), TAJIKISTAN, Varzob botanical Station, 30.07.1945 (V.V.Gussakovski) [ca 38°50'N, 68°50'E]. KAZAKHSTAN, Almaty Area: 1♂ 3♀ 1juv. (ZMMU), environs of Bakans Town, tugai and thicket, June 1986 (Ch.K. Tarabaev); 1♀ (AGA), Charyn River canyon, Sartogai Boundary, 12.06.1993 (S.V. Ovchinnikov). RUSSIA, Tuva: 1♂ 4♀ (IBPN), Tere-Khol’ Lake, Sharlaa Stand and around, 40°01.47'N, 95°03.45'E, 1150 m, 6-14.07.1996 (Yu.M.Marusik); 1♂ 1♀ (ISEA), Tere-Khol’ Lake, SE shore, Eder-Elezin Sands (Desert), 1150 m, 12.07.1993 (Yu.M. Marusik); 1♂ (ISEA), Tere-Khol’ Lake, S shore, sands with sparse Caragana shrubs, 6-26.05.1990 (O. Lyakhov).

Diagnosis.

Habitus, pattern and copulatory organs of Araneus strandiellus resemble only those in Araneus pallasi . Both species have simple, weakly sclerotised epigyne with inflexible scapus; males lack stipes, subterminal apophysis, embolic cup, and have weakly sclerotised conductor; long filamentous embolus; long (as embolus), narrow terminal apophysis; median apophysis with one prolaterally directed process (Fig. 9-17) (much shorter non filamentous embolus, and median apophysis with two processes in majority of Araneus s.s., e. g. diadematus group ( Levi 1971)) and males have unmodified tibia II. Araneus strandiellus can be distinguished from sibling Araneus pallasi by having dorsal abdominal humps, and triangular scapus with pocket (wide, round scapus in Araneus pallasi ). Males of these two species can be separated from other Araneus species by the round base of embolus, absence of the hump on tegulum and having longer median apophysis (Fig. 12, 16) with a triangular process in Araneus strandiellus (Fig. 14), and claw-like in Araneus pallasi (Fig. 15).

Description

(specimens from Kazakhstan)

.

Male. Total length 3.0. Carapace 1.4 long, 1.3 wide. Length of patella + tibia I 2.15 (patella 0.7; tibia 1.45). Carapace pale brown, covered with pale hairs; indistinctly darker on margins and with elongate whitish median spot (Fig. 6). Cephalic area of carapace slightly protruding. Diameter of AME subequal to PME. Distance between PME 1.3 times longer than between AME. Basal part of chelicera and retrolateral side dark brown. Promargin of chelicera with 3 teeth, retromargin with 2 small teeth. Sternum brown, with wide light spot in the centre (Fig. 7). Dorsum of abdomen with pair of small humps (Fig. 6). Humps separated by less than one diameter. Abdomen dark brown, with two white transverse bands. Venter of abdomen with dark median band, and whitish lateral bands (Fig. 7). Legs with annulations. Tibia II unmodified, similar to tibia I. Femur I prolaterally with 4 strong and long spines (Figs 5, 8) and with 7 short strong retrolateral spines.

Palp as in Figs 9-14. Patella with 2 macrosetae. Tegulum enlarged and all sclerites (embolus, conductor, radix, terminal and median apophyses) partly hidden by tegulum and cymbium. Terminal apophysis (Ta) long, flat, semicircular and weakly sclerotised; it runs apically between cymbium and tegulum. The long, thin and well sclerotised filiform embolus (Em) follows a groove in the terminal apophysis. Radix (Ra) short, stipes absent. Conductor (Co) very small, weakly sclerotised; supports tip of embolus from below. Median apophysis (Ma) with relatively small, triangular process (Pm) directed prolaterally.

Female. Total length 2.75-4.0. Carapace 1.25-1.45 long, 1.2-1.4 wide. Length of patella + tibia I 1.9-2.15 (patella 0.6-0.7; tibia 1.3-1.5). Coloration and pattern of carapace as in male, but paler (Figs 1-3). Diameter of AME 1.3 times smaller than PME. Distance between PME 1.4 times longer than distance between AME. Cheliceral teeth as in male. Frontal part of chelicerae yellow, retrolateral side dark. White spot in the centre of sternum wider than in male.

Dorsum of abdomen with pair of conical humps separated by less than one diameter. Abdomen pale with dark pattern (Fig. 1). Venter of abdomen white between epigastric furrow and spinnerets; white area as wide as epigastric furrow (Fig. 2).

Femur I with 2-3 strong, long and pale spines (Figs 4). Legs yellow, with indistinct dark annulation. Ventral side of femur pale in almost all length. Patella pale with indistinct dark spot. Tibia and metatarsi without central dark rings or with small, dark spots.

Epigyne as in Figs 18-21, flat with weakly sclerotised inflexible triangular scapus (i.e. immovable merged with base of epigyne); tip of scapus with pocket (Sp); copulatory ducts and spermatheca slightly visible through cuticle. Base of epigyne always embedded in epigastric furrow, therefore posterior part visible only after its dissection or excavation.

Variations.

Specimens from Tuva have darker coloration, lack white spot on carapace and sternum. Females from Tuva have no wide median band on the venter of abdomen. Importance of these differences is unclear to us.

Distribution.

The species is known from the Aral Sea to eastern Tuva (Fig. 22) south to Tajikistan.

Comments.

Generic affinity to Araneus ,a genus comprising over 600 species (cf. Platnick 2012), is debatable. In comparison to Araneus s. s., Araneus strandiellus has only 3 promarginal and 2 retromarginal teeth (4 promarginal and 3 retromarginal in Araneus s.s.); females do not have heavy sclerotised epigyne and flexible scapus; and males lack stipes, subterminal apophysis and cap on embolus, conductor is very small and weak sclerotised and median apophysis has only one process.

Judging from the general shape of epigyne (presence of inflexible scapus) and the male palpal configuration (shape of median and terminal apophysis, embolus) Araneus strandiellus and probably the closest relative Araneus pallasi mostly resemble Neoscona Simon, 1864 (one of the junior synonyms of Araneus pallasi was considered in Neoscona ) or Agalenatea Archer, 1951. However unlike Araneus strandiellus and Araneus pallasi , males of both Agalenatea and Neoscona have stipes and subterminal apophysis, an anticlockwise course of embolus, legs with hook on coxa I and modified tibia II (more numerous and stronger spines than on other legs). Epigyne of these two related species are weakly sclerotised and embedded in epigastric furrow (posterior part visible only after its dissection or excavation), while in Agalenatea and Neoscona epigyne are not embedded and heavy sclerotised.