Redescription of a wall crab spider species from Taiwan: Siamspinops formosensis (Kayashima, 1943) comb. Nov., with the first description of males and taxonomic notes (Araneae: Selenopidae)

Abstract

The wall crab spider Selenops formosensis Kayashima, 1943 was described from three females collected from northern Taiwan (Kayashima 1943a), but subsequently referred to as S. formosanus and S. formosansis in an illustrated handbook on Taiwanese spiders written by the same author (Kayashima 1943b). The original descriptions lacked illustrations of the epigyne or vulva which are extremely useful in determining genera and species of Selenopidae. The genus Pakawops Crews & Harvey, 2011 was erected to accommodate this endemic Taiwanese species, but they used the spelling ‘P. formosanus’. Crews and Harvey (2011) separated Pakawops from other selenopid genera based on the number of paired spines located on the ventral tibiae and metatarsi of legs I and II. However, no specimens were available to Crews and Harvey (2011), and the type was lost (Hirotsugu Ono, personal communication, 11 October, 2017), and they relied on the original, rather imperfect descriptions (Kayashima 1943a, 1943b). Based on newly collected specimens from several localities in Taiwan, this study presents a modern redescription of Selenops formosensis, allowing us to assess the status of Pakawops. Our study shows that Kayashima’s descriptions of the number of spines on the tibiae and metatarsi of legs I and II appear to be incorrect, and that the species is referable to the genus Siamspinops Dankittipakul & Corronca, 2009. This renders Pakawops as a junior synonym of Siamspinops. We also describe the male of this species for the first time. The materials examined in this paper are deposited at the Taiwan Endemic Species Research Institute (TESRI) and Department of Life Science, National Taiwan Normal University (NTNUB). The measurements of palps consist of femur, patella, tibia and tarsus while those of legs consist of femur, patella, tibia, metatarsus and tarsus. All measurements are given in millimeters. Variation values are given as “Mean ± SD”. And the description of spine number follows Dankittipakul and Corronca (2009). Abbreviations used: AER: Anterior Eye Row; ALE: Anterior Lateral Eyes; AME: Anterior Median Eyes; MOA: Median Ocular Area; PER: Posterior Eye Row; PLE: Posterior Lateral Eyes; PME: Posterior Median Eyes