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Redescription of Central Asian orb-weaver Araneus strandiellus Charitonov, 1951, only known from the original description of female. The male of this species, previously unknown, is described here for the first time.
Central Asia, orb-weaver, taxonomy, redescription
Araneidae with 3029 species belonging to 168 genera is third largest spider family (
The orb weaving spider Araneus strandiellus Charitonov, 1951 is only known by female and since the description was never considered in any other taxonomical publication (cf.
While working with Araneidae material from Siberia and Central Asia we found several samples of Araneus strandiellus containing both sexes. The main goal of this paper is description of the male for the first time, and providing detailed redescription of the female.
Material and methodsMicrophotographs were made with an Olympus Camedia E-520 camera attached to an Olympus SZX16 stereomicroscope at the Zoological Museum, University of Turku. Digital images were montaged using “CombineZP” image stacking software. Figures were edited in Corel Photo Paint X4 and Corel Paint Shop Pro Photo X2. Specimens where photographed while placed in dish with paraffin on the bottom filled with 70% ethanol and using different sized holes to keep the samples in the required position. Studied material is deposited in Department of Zoology, Perm State University (PSU), Zoological Museum of Moscow State University (ZMMU), Siberian Zoological Museum of the Institute for Ecology and Systematics of Animals (ISEA), Institute for Biological Problems of the North, Magadan (IBPN) or Alexander V. Gromov (Almaty, Kazakhstan) personal collection (AGA). All measurements are in millimetres.
Taxonomyhttp://species-id.net/wiki/Araneus_strandiellus
Figs 1–14, 18–21Holotype ♀ (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).
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 (
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.
Habitus of Araneus strandiellus. 1–3 female, dorsal, ventral and lateral 4 female carapace and femora I and II, prolateral 5 male femur I, prolateral 6–7 male, dorsal and ventral 8 prosoma of male, lateral.
Copulatory organs of Araneus strandiellus (9–14, 18) and Araneus pallasi (15–17). 9–17 left male palp 9 prolateral 10 ventral-anterior 11 ventral-posterior 12 cymbium removed, prolateral 13 same, ventral 14 median apophysis, ventral 15 same 16 cymbium removed, prolateral 17 same, ventral 18 epigyne, posterior. Co conductor Em embolus Ma median apophysis Pm terminal process of median apophysis Ra radix Sp pocket on scapus of epigyne Ta terminal apophysis.
Epigyne of Araneus strandiellus. 19 lateral 20 ventral 21 posterior. Sp pocket on scapus of epigyne.
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.
The species is known from the Aral Sea to eastern Tuva (Fig. 22) south to Tajikistan.
Known collecting localities of Araneus strandiellus.
Generic affinity to Araneus, a genus comprising over 600 species (cf.
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.
We thank Sergei L. Esyunin (PSU) for the loan of the holotype of Araneus strandiellus.Alexander V. Gromov provided us with information about occurrence of Araneus strandiellus in Charyn Canyon (Kazakhstan). Special thanks go to Seppo Koponen who allowed us to use equipment in the Zoological Museum of the University of Turku. English of an earlier draft of this manuscript was kindly checked by Donald Buckle. This work was supported in part by the Russian Foundation for Basic Research (grant № 11–0401716 and 12-04-01548). Last but not least, we thank reviewers for their valuable comments.