Pselaphodes walkeri (Sharp, 1892)

Yin, Zi-Wei & Li, Li-Zhen, 2013, On the identity of Pselaphodes walkeri (Sharp, 1892) (Coleoptera: Staphylinidae: Pselaphinae), with description of a new related species, Zootaxa 3609 (3), pp. 327-334 : 328-329

Pselaphodes walkeri (Sharp, 1892)

( Figs. 1 A, 2, 4)

Type material examined. Holotype: CHINA: 3, labeled ‘3 / Eulasinus / walkeri / Type D. S. / Chusan, Walker / June 1892 // Type / H. T. // Eulasinus / walkeri Sharp / Cl. Besuchet / dét. IX 1978 // HOLOTYPE / Pselaphodes / walkeri SHARP / P. Hlaváč det., 2001’ (BMNH).

Other material examined. CHINA: 4 33, 2 ƤƤ, labeled ‘ CHINA: Zhejiang, Zhoushan Arch. / Damao Is., Meiwan Village, alt. 52 m / 29°57ʹ0 7ʺN 122°01ʹ58ʺE (leaf / litter of Cunninghamia lanceolata / & Hedera nepalensis var. sinensis , / sifted) 2012. X.13, Xiao-Bin Song leg.’ All bearing the following identification label: ‘Col: Pselaphinae / Pselaphodes / walkeri (Sharp, 1892) / det. Yin, X. 2012 / SHNU Collection’ (SNUC).

Diagnosis. Reddish brown; length 2.80–3.20 mm; postgenae rounded; antennomeres IX–XI enlarged, IX–X modified in the male; pronotum with lateral margins broadly rounded at anterolateral margins; metaventrite with short blunt processes; metacoxae simple; aedeagus with asymmetric median lobe.

Redescription. Male ( Fig. 1 A). Length 3.02–3.20 mm. Head about as long as wide, HL 0.60–0.63 mm, HW 0.61–0.62 mm; eyes each composed of about 35 facets. Antennal clubs as in Fig. 2 A. Pronotum ( Fig. 2 B) as long as wide, PL 0.60–0.63 mm, PW 0.61–0.63 mm, with lateral margins nearly rounded anterolaterally. Elytra wider than long, EL 0.82–0.85 mm, EW 1.16–1.23 mm. Metaventrite with processes short and truncate apically ( Fig. 2 C). Protrochanters with thin ventral spine, profemora with large thin ventral spine ( Fig. 2 D), protibiae with small apical tubercle ( Fig. 2 E); mesotrochanters ( Fig. 2 F) with two small ventral spines; metatrochanters and metafemora ( Fig. 2 G) simple. Abdomen broad at base and narrowed apically, AL 1.00– 1.09 mm, AW 1.22–1.28 mm. Sternite IX as in Fig. 2 H. Aedeagus length 0.64 mm, with asymmetric median lobe ( Figs 2 I–K).

Female. Similar to male in general; BL 2.80–2.97 mm, HL 0.59–0.61 mm, HW 0.59–0.60 mm, PL 0.59–0.60 mm, PW 0.62–0.63 mm, EL 0.73–0.77 mm, EW 1.16–1.17 mm, AL 0.89–0.99 mm, AW 1.28–1.29 mm. Eyes each composed of about 30 facets. Antennae lacking modification; metaventral processes absent.

Comparative notes. Pselaphodes walkeri is placed close to P. pseudowalkeri described below by sharing a similar general habitus and form of the antennal clubs, short metaventral processes, and similar placement of the leg spines/tubercle. In P. walkeri , the body size is larger (3.02–3.20 mm), each eye is composed of about 35 facets (30 in female), each antennomere X has a large cavity on the mesal half of the dorsal surface, and the aedeagus has complicated sclerites in the endophallus, while P. pseudowalkeri is slightly smaller (2.63–2.82 mm), has each eye composed of about 45 facets (40 in female), each antennomeres X lacks an obvious cavity on the upper surface, and the endophallus of the aedeagus is composed of a single sclerite.

Both P. walkeri and P. pseudowalkeri can be separated from all known Pselaphodes species, except P. n o m u r a i Yin, Li & Zhao and P. declinatus Yin, Li & Zhao , by the nearly triangular antennomere IX in the males. Pselaphodes nomurai has the pronotum with greatly angulate anterolateral margins and P. declinatus has antennomere X broadly and deeply incised at the mesal margins.

Distribution. This species is currently known only from Damao Island of the Zhoushan Archipelago. We have examined a single female Pselaphodes from the Putuo Shan Island (ca. 35 km ENE Damao Island) that is similar to P. walkeri female in body size and general appearance, identification of this female requires future collection of an associated male.

Ecology. As Sharp noted (Sharp, 1892: 241), the holotype was collected in the moss under a stone at the summit of the island in June, while our material was collected in October. The two-day trip to Damao ( Fig. 5 A) was in the middle of the dry season, with more than a month rainless. On the first day, no staphylinid of any kind was discovered by sifting leaf litter in the forests of the mountain. All specimens were collected on the second day by X.-B. Song ( Fig. 5 B) along a path in the village ( Fig. 5 C), just before departure from the island. The area from which the individuals were collected was less than 50× 50 cm 2, filled with leaf litter of Cunninghamia lanceolata ( Figs. 5 D, E); and no other staphylinids were found there; however, two females of an unidentified Labomimus species were collected with Pselaphodes walkeri at the same location.

Figures

FIGURE 1. Dorsal habitus of P. walkeri (A) and P. pseudowalkeri (B). Scales (mm): 1.0.

FIGURE 2. Diagnostic features of P. walkeri. A. Antennal club. B. Pronotum. C. Metaventral process, in lateral view. D. Protrochanter and profemur. E. Apical portion of protibia. F. Mesotrochanter and mesofemur. G. Metatrochanter and metafemur. H. Sternite IX. I. Aedeagus, in dorsal view. J. Same, in lateral view. K. Same, in ventral view. Scales (mm): A, B, D, F, G = 0.3; C, I, J, K = 0.2; H = 0.1; E = 0.05.

FIGURE 5. Collecting at Damao Island. A. An overall view of the island. B. Wen-Xuan Bi (left), Xiao-Bing Song (middle) and Zi-Wei Yin (right) at Damao Island. C. The village where Yin, Song and Bi stayed during the collecting trip (arrow indicating the collection site). D. Collection site, a path surrounded by abandoned houses in the village (arrow indicating the collection area that is full of leaf litter of Cunninghamia lanceolata). E. A closer view of Cunninghamia lanceolata.