Alopecosa albostriata

Alopecosa albostriata (Grube, 1861)

Figs 1–22, 35

Lycosa (Tarantula) albostriata Grube, 1861: 174 (juv.).

Lycosa albostriata: Schmidt 1895: 462 (♀).

Tarentula albostriata: Kulczyński 1908: 71, pl. 3, f. 84, 89, 94 (♂ ♀).

Alopecosa albostriata: Roewer 1955: 213 (transfer to Alopecosa).

Alopecosa albostriata: Wesołowska 1988: 406, f. 9‒11 (♀).

Note 1. All other references (in total 32) listed under A. albostriata in Platnick (2014) and World Spider Catalog (2018) refer to other species, related to Mustelicosa dimidiata (Thorell, 1875).

Note 2. Although the type was not studied, the species was recognized based on the figures provided by Kulczyński (1908) and material from Yakutia listed below and studied earlier (Marusik et al. 1993).

Material examined: RUSSIA: 1♂ (ISEA), Krasnoyarsk Prov., Turukhansk Dist., Tsentralno-sibirski Reserve, Yenisei R., Komsa kordon, 61.84°N, 89.45°E, 25–30 m, 19 – 26.06. 2016 (V.K. Zinchenko); 17♂ 1♀ (ZMMU), Yakutia, Yana River, middle flow of Tuostakh River (right tributary of Adycha River), ca. 67°17’N, 137°07’E, Summer 1989 (V.V. Sivtsev); 15♂ 2♀ (IBPN), Magadan Area, Kulu River upper flow, Kontakt Field Station, 61°51’N, 147°40’E, 500 m, Summer 1999 (S.P. Bukhkalo).

Comparative material: Alopecosa mutabilis: RUSSIA: 1♂ 15♀ (ZMMU), Arkhangelsk Area, Barents Sea, Dolgiy Island, Nenets Reserve, 69°12’N, 59°13’E, 6– 28.07.2004 (O.L. Makarova); 32♂ 15♀ (IBPN), Chukotka, Wrangel Island, SE part, Mamontovaya River middle flow, 71°10’N, 179°46’W, June–July 2006 (O.A. Khrulyova).

Diagnosis. Males of A. albostriata can be easily distinguished from congeners occurring in Siberia by the light tibia-tarsi, which lacks any pattern (other species have dark tibia-metatarsi or transversal bands) and longitudinal whitish stripe on abdomen (found in majority of specimens). The male palp of A. albostriata is most similar to those of A. mutabilis, but differs by having broad tegular apophysis with a flat and bent tip and a triangle outgrowth (Figs 16, 24), all absent in other Alopecosa species. Two similar species well differ by pattern: highly variable on carapace and abdomen in A. mutabilis (not variable carapace pattern in A. albostriata), but lacking white abdominal stripe and light tibia-tarsi. Additionally, the embolus in A. albostriata is longer than in A. mutabilis (cf. Figs 17–18, and 29–30).

Females of A. albostriata differ from Siberian congeners by having a dorsal, white abdominal stripe (present in most of specimens) and shape of epigyne with septum wider than long and receptacles having a long mesal outgrowth (Ro), which is as long as the copulatory (=insemination) ducts (Id) (Figs 5–7). Epigyne of A. albostriata are most similar to those in A. mutabilis. The latter species differs by higher basal part of septum (Figs 26–28) and mesal outgrowth of receptacle as long as copulatory duct diameter (figs 525–526 in Dondale & Redner 1990).

Description. Male (specimen from Kontakt Field Station). Total length 8.75. Carapace 4.5 long, 3.45 wide. Carapace brown, with light median band, and almost distinct marginal, wide light band. Femora I brown, femora II light brown, femora III and IV yellow with brown dorsal side. Patella yellowish with darker proximal part, tibiatarsi yellowish. Abdominal color pattern as shown on Fig. 3. Leg measurements as given in the Table 1 and spination as given in the Table 2.

Male palp as in Figs 8–21; brown, femur as long as tibia and patella; patella as long as tibia, cymbium slightly shorter than femur (femur/cymbium length ratio 1.11). Terminal part of cymbium long (2.25 times shorter than the entire cymbial length). Bulb 1.4 longer than wide in lateral view (Fig. 11) and as long as wide in anterior view (Fig. 10). Tegular apophysis weakly sclerotized, as wide as high, with flat triangular tip, which is bent meso-anteriorly (Tt), and a small triangular outgrowth (To). Both embolus and synembolus hidden by tegular apophysis. Synembolus (Se) long and flat (in anterior view). Embolus (Em) long, filamentous with roundly bent tip.

Variation. Total length 8.2–9.0, carapace 4.25–4.5 long. Marginal light band on carapace well distinct in some specimens (Figs 2, 4). Abdominal pattern variable, from basic one (Figs 2, 4) to those with longitudinal white stripe formed by whitish setae (most of specimens).

Female (from Kontakt Field Station). Total length 11.7. Carapace 5.2 long, 3.8 wide. Coloration as in male, but lighter. Lateral light bands on carapace distinct. Legs light colored with almost indistinct broad dark transversal bands. Leg length and spination as given in Tables 3 and 4.

Epigyne as in Figs 5–7, 22; plate wider than long; anterior part of plate with a shallow depression (Sd) with dense setae; fovea almost completely covered by the septum, remaining part of fovea slanting, droplet shaped; septal stem (Ss) short, shorter than septal base height, as wide as long; base of septum (Sb) 2.5 times wider than long; receptacles with 2 arms, lateral arm terminating by head (Rh), head about 2 times wider than copulatory duct diameter; mesal outgrowth (Ro) cylindrical, about as long as copulatory duct; mesal arms separated by 2 diameters.

Comments. Grube (1861) provided a description of juvenile specimen (junior ♀) without specifying number of syntypes, Wesołowska (1988) while redescribing Grube’s types indicated that syntype specimens of A. albostriata contain both a female (selected as the lectotype) and juveniles. Grube (1861) indicated type locality as “Ad flumen Wilui (Maack)” (=on river Vilyuy (leg. Maack)). R.K. Maack organized an expedition to Western Yakutia in 1854–1855, and travelled along the whole Vilyuy River stream and reached northernmost tributaries of the river (ca. 68°N) (Maack, 1877 –1886). Therefore, this species could be collected in any part of his long route and exact type locality is unclear.

Habitats. In the eastern Siberia it occurs in various biotopes within the forest belt, though always rather rare. In the vicinities of the Aborigen Field Station it reaches some kind of abundance (between 2 and 5% in pitfall trap samples collected over five years, in 30 different habitats, with total number of spiders more than 120 thousands (Marusik 1988) only in north exposed slope with thin larch forest with Ledum -cowberry-moss-lichen litter. While it is often associated with moss litter in larch stands, it was found in gravely shores of small creeks and rivers also (personal data). Eskov (1988) mentioned that this species occurs in larch forests with green mosses grown on the ground.

Distribution. World Spider Catalog (2018) cites distribution of this species as Kazakhstan, Russia, China and Korea, but it seems that A. albostriata is distributed exclusively in Russia, from Yenisei River to Kolyma River, and from Taimyr Peninsula and Lena River mouth (ca. 71° N) to southeastern Tuva (ca. 51° N) and southern Transbaikalia (ca. 49.5° N) (Fig. 35). Most likely it occurs in adjacent northern Mongolia and northern Inner Mongolia. A record from Lena River mouth, located in the tundra zone (Marusik et al. 1993) may refer to sibling A. mutabilis. Numerous records of this species from China and Korea under A. albostriata or species names considered as junior synonyms (see World Spider Catalog 2018) refer to Mustelicosa Roewer, 1960 species.

Relationships. Alopecosa albostriata, together with A. mutabilis (Kulczyński, 1908) and A. exasperans (O. Pickard-Cambridge, 1877) form its own species group, that can be called albostriata- group (albostriata is the oldest name among the three species). The three species have very similar copulatory organs (Figs 23–30, and figs 514–526 in Dondale & Redner 1990) and display high polymorphism in abdominal pattern as well as variable pattern of carapace, especially in A. mutabilis and A. exasperans. Alopecosa albostriata has pronounced variation of abdominal pattern, almost dimorphic (as shown on Figs 3–4), however some specimens exhibit a derived pattern. This species group has Siberian-Nearctic distribution and occurs from eastern part of Arkhagelsk Area to Greenland. Alopecosa mutabilis and A. exasperans are restricted exclusively to tundra zone, while A. albostriata is known in boreal one. One record, from Lena River delta, requires confirmation and may refer to A. mutabilis.

Copulatory organs of the albostriata -group are rather different from these in A. fabrilis (Clerck, 1757), the type species of the genus (cf. fig. 1a–f in Lugetti & Tongiorgi, 1969), but very similar to these in the Mustelicosa dimidiata (Thorell, 1875), the type species of Mustelicosa Roewer, 1960 (Figs 31–34 and figs 1–17 in Marusik & Buchar 2004 and 22.10, 22.13 in Marusik & Kovblyuk 2011). Both groups have epigynal septum wider than high (long), short stem (shorter than basal part), broad and weakly sclerotized tegular apophysis with tip bent mesoanteriorly (septum longer than wide, stem at least as long as basal part of septum, tegular apophysis well sclerotized, tip bent directed mesally (horizontal) in A. fabrilis). Further morphological studies combined with molecular data may reveal that albostriata -group should be transferred to Mustelicosa.