Two poorly known species of the spider genus Ambanus (Arachnida: Araneae: Amaurobiidae) in Korea

Two poorly known spider species of the genus Ambanus from Korea are revised with detailed illustrations, leg spination, trichobothrium patterns, and SEM photographs. Ambanus lunatus (Paik, 1976), previously misidentified in Korea as Ambanus spp., is redescribed with the first description of the male. The type species of the monotypic genus Alloclubionoides Paik, 1992 (Clubionidae), Alloclubionoides coreana, described only from the male holotype, is transferred to Ambanus with the first description. Furthermore, the female paratype of Coelotes paikwunensis and female specimens described as A. lunatus in Korea are in fact the females of A. coreana.


Introduction
The genus Ambanus of the family Amaurobiidae comprises 18 species including the species transferred from the genus Coelotes based on the type species A. mandzhuricus Ovtchinnikov, 1999. Of these, 10 species are endemic to Korea, four to Russia, three to China, and one to Japan (Wang 2002;Platnick 2006). Wang (2002) revised the subfamily Coelotinae at the generic level based on 31 characters and 22 taxa, including two outgroup taxa (Tamgrinia, Amaurobius). In his revision, Wang (2002) mentioned 18 species of the genus Ambanus but was able to study only the females of two of the 10 Korean species, A. lunatus and A. quadrativulvus. The remaining eight species have not yet been examined closely for their genitalic characters such as the median apophysis, conductor, embolus, conductor dorsal apophysis, and cymbial apophysis in the male palpal organ, and inner atrial margin, hood, and position of atrium in the female epigynum. Although Namkung (2001Namkung ( , 2003 presented simple illustrations of nine Ambanus species [A. bifidus (Paik, 1976), A. dimidiatus (Paik, 1974), A. euini (Paik, 1976), A. kayasanensis (Paik, 1972), A. kimi (Paik, 1974), A. lunatus (Paik, 1976), A. ovatus (Paik, 1976), A. paikwunensis , and A. quadrativulvus (Paik, 1974)], these species cannot be reliably identified from his pictorial book. Alloclubionoides coreana Paik, 1992 was originally described on the basis of a single male from the Korean national arboretum of Gwangrung (KNAG), Pocheon-gun, Gyeonggi-do. To date, the only recorded specimens of this species have been males from the same locality.
During a survey of the spider fauna of Korea, spiders of the genus Ambanus were collected from pitfall traps near the type locality of A. paikwunensis (Mt. Paikwun, Pocheon-gun, Gyeonggi-do) and Alloclubionoides coreana (KNAG), and at Mt. Yebong, Namyangju-si, Gyeonggi-do. The male specimens collected at two sites (Mt. Paikwun, KNAG) corresponded well with the description of A. coreana, as well as the type species of the monotypic genus Alloclubionoides in the family Clubionidae. The specimens are therefore thought to be the male of Ambanus coreana, and characterized by having three claws (two in Clubionidae), median apophysis not ear-shaped (or spoon-like), and no patellar apophysis. Females collected at the same locality by pitfall are concluded to be the true females of A. coreana, and not to A. lunatus as would be suggested by previous taxonomic classifications. The genitalic characters of the latter species are very similar to those of A. coreana, with both species having the following characteristics: epigynal teeth absent; atrial septum originating in posterior plate; atrium slit or true copulatory pore, deep, oblique line-shaped on inner retrolateral part of both semicircular hoods; copulatory ducts broadly curved with transparent membranes; spermathecal heads small cylindrical processes; spermathecae short, overlapped, with indistinct stalks and bases; fertilization ducts very small, arising from the posterior margin tip of the spermathecae; patellar apophysis absent; retrolateral tibial apophysis modified with intermediate tibial apophysis; cymbial furrow short, less than half cymbial length; conductor broadly saucer-like with many minute denticles; conductor dorsal apophysis situated on distal embolus; embolus broad and short, wound counterclockwise, distal part cup-shaped.
The main goal of this paper is to provide research data for the future revisional study of the Korean endemic spider genus Ambanus.

Materials and methods
Collection sites were located beside a small stream, with vegetation characterized by a mixture of patchy fir plantations and secondary broadleaf woods. Ten pitfall stations were established in several natural forests (KNAG, Mt. Paikwun, Mt. Yebong, Mt. Odae), the central districts of Korea. At each station two pitfall traps (plastic cups, height 6.3 cm, diameter 8 cm) were set 10 m apart and filled with ethylene glycol (Greenslade and Greenslade 1971). Measurements are in mm unless noted otherwise. Specimens examined in this paper will be deposited in the National Biological Resources Center (NBRC) and Arachnological Institute of Korea (AIK).

Diagnosis
This species is similar to A. coreana, A. napolovi Ovtchinnikov, 1999, A. paiki Ovtchinnikov, 1999, and A. quadrativulvus (Paik, 1974 in having female epigynum with atrium very broadly oval, situated posteriorly near epigastric furrow; copulatory pore deep, linear on inner lateral part; copulatory ducts broadly curved with transparent membranes in both posterior margins; male palpal organ with cymbial furrow less than one-third cymbial length; large embolus with curved distal part; and conductor saucer-like, with a rounded distal end situated on centre of papal organ. Ambanus lunatus female can be distinguished by the presence of a semicircular swollen atrial hood; distinctive atrial septum triangularly expanded, originating in posterior plate; chelicerae with three promarginal teeth; and spermathecal stalk overlapped in the middle; the male by an embolus with two distal parts with cup-shaped processes and another divided into two protrusions facing the retrolateral side; cymbial furrow short, about one-fifth the cymbial length.