Eupoa Żabka , 1985

Logunov, Dmitri V. & Marusik, Yuri M., 2014, Taxonomic notes on the genus Eupoa Żabka, 1985 (Arachnida, Araneae, Salticidae), ZooKeys 410, pp. 63-93 : 64-66

Genus Eupoa Żabka, 1985

Eupoa Żabka, 1985: 220. Type species: Eupoa prima Żabka, 1985; by monotypy.

Description.

Small to very small spiders ranging from about 1.65 to 2.45 mm in length. Sexes similar in general body form; sexual dimorphism is poorly marked and can be seen in the following characters: dorsal scutum presents in males (absent in females), body coloration in males is slightly darker or more contrastingly coloured, anterior and posterior pairs of spinnerets are of contrasting colours in males (brown/dark grey vs. yellow; e.g., Eupoa prima , Eupoa yunnanensis ), and legs I and II in males are often with no spines or just with 2/3 pairs of ventral spines on metatarsi (always with spines on tibiae and metatarsi in females; e.g., Eupoa schwendingeri sp. n., Eupoa yunnanensis ). Carapace: rather high, with abruptly declining, practically vertical thoracic part (Figs 6, 59, 90); sparsely covered with white elongated pinnate scales (Figs 1-3); fovea absent (Figs 73, 75); lateral sides of carapace, near ALEs, with vertical rows of skin structures (50-60 in a group) looking like either as rounded or elongated smooth bare patches, slightly risen above the surrounding skin (Figs 20, 22), or as flat elongated patches with what looks like several micro-pustules situated on them (Fig. 18); similar bare skin structures occur on leg patellae (see below; Figs 20-21). Eyes: in three rows, with large black areas around eyes (Figs 42-46, 58-59); anterior eye row wider in both sexes, so the quadrangle is as an inverted trapezium; second row midway between ALE and PLE; quadrangle length 52-66% of carapace length. Clypeus: narrow, about 17-47% of AME diameter (from frontal view; Figs 4-5), visibly backward sloping (Figs 6, 59). Chelicerae: small and vertical (Figs 4-5, 7; promargin with two small teeth; retromargin with three small teeth (Fig. 8). Maxillae: slightly convergent; usual shape. Labium: transverse-ovoid. Sternum: as inverted cone with swollen lateral sides (Figs 30, 72, 76). Pedicel: short, in live specimens not visible in dorsal view. Abdomen: elongate, covered with elongated pinnate scales (Fig. 32); dorsal scutum present in males; colour markings on dorsum simple, either consisting of a median yellow stripe (Figs 41, 43, 45) or two rows of spots with a pair of largest sports at the rear of dorsum (Figs 85-86). Book-lung covers: usual shape, not sclerotized. Spinnerets: posterior pair almost two times longer than anterior pair (Figs 31-32). Legs: subequally developed (Fig. 9); legs I in males usually with dark brown longitudinal stripes; trichobothrial bases relatively flat and striated (Fig. 14); tarsal organ as a rounded or ovoid pit (Figs 12-13); tarsal claws narrow, with poorly developed teeth (Figs 10-11); skin structures of two kinds present anteriorly on the dorsal surface of leg patellae, situated in a longitudinal row of about 20-30 pores (arrowed in Figs 19, 21, 23-24): structures of the first kind represents flat elongated and smooth bare patches with what looks like several micro-pustules situated on them (Figs 17, 24); structures of the second kind look like a rounded or elongated or circular smooth bare patch, slightly risen above the surrounding skin (Figs 21; similar bare structures occur on the carapace, see above, Figs 20, 22), these structures resemble the second kind of skin pores described in Neon ( Logunov 1998: figs 7, 11). Leg formula: IV,I,III,II in both sexes, rare IV,I,II,III in females. Leg spination: in males legs I and II are often spineless (or with a few spines on Mt I: v 2 –2– 2ap); in females Tb I v 2 –2– 2ap, Tb II pr and rt 0 –1– 0, v 1-1/0 and Mt I and II v 2 –2– 2ap; in both sexes Tb III and IV usually pr and rt 0 –1– 0 (or 0-1). Female palp: general form; with an apical claw (arrowed in Figs 15-16). Male palp: swollen and relatively large for the size of the spiders (Figs 42-43); femur of usual shape, except for Eupoa prima (Figs 80-83), shorter than cymbium; patella swollen, with one (Figs 61, 70, 84, etc.) or two (Fig. 80) apophyses that sometimes are as long as the femur ( Eupoa prima ; Fig. 80) or poorly-developed and inconspicuous ( Eupoa lehtineni sp. n.; Fig. 50), or sometimes bifid (Figs 96, 126); tibia shorter than patella, with one or two tibial apophyses (Figs 49, 59, 116, etc.) that sometimes are poorly-developed ( Eupoa prima ; Figs 81, 84) or covered with long hairs ( Eupoa thailandica sp. n.; Fig. 111); cymbium well-developed, sometimes with bunches of white hairs at its basis (e.g., in Eupoa thailandica sp. n.; Figs 106-107); tegulum well-developed (sometimes on one side of the bulb only; e.g., in Eupoa pappi sp. n.; Figs 70-71) and usually with tegular apophysis (Figs 52, 60, etc.), which sometimes poorly-developed (e.g., in Eupoa schwendingeri sp. n.; Fig. 98) or even absent (e.g., in Eupoa pulchella sp. n.; Figs 91-96); median apophysis present (Figs 49, 83, etc.), but sometimes poorly-developed (e.g., in Eupoa pappi sp. n.; Figs 67-68); compound terminal apophysis present and situated inside the apical cavity of tegulum, either thin and long (Figs 52, 61) or strong, with a longitudinal groove on its anterior edge (e.g., in Eupoa pappi sp. n. or Eupoa thailandica sp. n.; Figs 66-68, 109); embolus usually very long and coiled, making 1.5-2 revolutions, with its terminal end resting on top of the cymbium (Figs 36, 51, 62), or can be short (Fig. 94) and even fingerlike and apically bifurcated in some species ( Eupoa yunnanensis ; Fig. 125). Female copulatory organs: simple, with a pair of copulatory openings that usually spaced up from each other and poorly visible on the epigynal plate; epigynal plate flat (Figs 29, 48, 100) or sometimes with a central shallow atrium ( Eupoa yunnanensis ; Fig. 127), usually covered with long light hairs (Figs 39-40); insemination ducts relatively short, directed to each other (Fig. 101; see also Żabka (1985: fig. 169) or being subparallel (Figs 53, 118); receptacles rounded or bean-shaped, usually much stronger sclerotized than insemination ducts (Figs 53, 118, 128); in most species receptacles and fertilization ducts are situated at the posterior end of the vulva (near the epigastric furrow), but sometimes lie at its anterior end ( Eupoa lehtineni sp. n.; Figs 53-54).

Diagnosis and affinities.

Of the described salticid genera, Eupoa is closest to Corusca Zhou & Li, 2013 (10 species) and Sinoinsula Zhou & Li, 2013 (12 species) known from Hainan Island of China ( Zhou and Li 2013a, b). Eupoa can vaguely be distinguished from Corusca by the presence of patellar apophysis in the males (except for Corusca viriosa Zhou & Li, 2013 and Corusca wuzhishanensis Zhou & Li, 2013) and the paired copulatory openings in the females. This is why none of the new species described in this paper has been assigned to Corusca , even Eupoa lehtineni sp. n. and Eupoa lobli sp. n. of which the conformation of male copulatory organs is very similar to that of the Corusca species. Eupoa can be distinguished from Sinoinsula by the conformation of copulatory organs in the males: viz., the presence of median apophysis and, more importantly, by the apical/medio-lateral origin of the embolus (prolateral in Sinoinsula ). Nevertheless, despite the aforementioned differences it is likely that the three genera are not only closely related but could even be treated as one, under the name of Eupoa . The original differential diagnoses of Corusca and Sinoinsula (see Zhou and Li 2013a) were purely based on a few characters of the copulatory organs, some of which vary (e.g., the presence/absence of the patellar, tegular or compound terminal apophyses), whereas somatic morphology was largely neglected. It seems that at least the limits of Corusca are unclear and can be reconsidered in the future. In the opinion of one of us (DL), the genera Corusca and Sinoinsula would be better considered the subgenera of Eupoa (s. lato), unless additional reliable diagnostic characters in somatic morphology were found. However, no synonymy is being made at this time. This problem is outside the scope of the present paper and will be considered in more detail in the future.

The phylogenetic relationships of Eupoa remain poorly resolved. On the basis of two morphological characters (presence of the median apophysis and a tarsal claw in the female palp; Figs 15-16) and molecular data, Maddison et al. (2007) argued that the genus Eupoa is a basal salticid of which phylogenetic placement lies outside the Salticoidea , and even outside the Spartaeinae (as it lacks a recognised tegular furrow; sensu Wijesinghe 1992). Obviously, further studies are required to resolve the correct phylogenetic placement of Eupoa .

Composition.

Currently, 12 species are included in Eupoa ( Platnick 2014; present data).

Distribution.

Eupoa seems to be restricted to the Oriental Region, for all the described species thereof as well as those of two closely related genera, Corusca and Sinoinsula , are restricted to SE Asia ( Żabka 1985; Peng and Kim 1997; Maddison et al. 2007; Zhou and Li 2013a; present data).