Pseudocsikia choui, Qiu & Kundrata, 2022

Qiu, Lu & Kundrata, Robin, 2022, Descriptions of two new flightless species of Pseudocsikia Schimmel & Platia (Coleoptera, Elateridae, Dimini) from Taiwan Island, China, with a definition of the formosana species-group, ZooKeys 1103, pp. 123-138 : 123

Pseudocsikia choui sp. nov.

Figs 1A , 3A-H , 5A-F

Type material.

Holotype, male, "2017.IX.13,台湾嘉义县阿里山二万坪, 2000m, 周文一” [Erwanping, Mount Alishan, Chiayi County, Taiwan, 2000 m, 13.IX.2017, Wen-I Chou leg.], " Pseudocsikia choui sp. nov. 周氏伪斯叩甲 HOLOTYPE des. Qiu et Kundrata 2022" (MYNU).

Diagnosis.

Head, pronotum, and elytra dark brown, with paler lateral portions of pronotum and elytra, legs yellow (Fig. 1A ). Antennomere II subequal in length to antennomere III. Pronotum (Fig. 3A ) smooth, with sparse punctures (intervals usually equal to 4-6 puncture diameters). Anterior angle of pronotum with apex of protrusion closer to inner angle. Posterior angles divergent. Metaventrite sparsely punctate, intervals between punctures on average subequal to 2-5 puncture diameters. Metacoxal plate (Fig. 3G ) enlarged mesally, sparsely punctate. Tergite IX (Fig. 5B ) subtriangular, with two narrow lobes. Aedeagus with median lobe with acute lateral projetions near midlength, narrowed to apex, apex blunt with small acute lateral projections. Paramere with apex pointed and projecting laterad. Phallobase with basal angles rounded (Fig. 5D ).

Comparison.

This species superficially resembles P. fomosana by the pale coloration of its pronotum and elytral sides and by the sparse punctures of pronotum, but it can be easily distinguished from the latter by the larger body length (5.9 mm, while 4.0 mm in P. formosana ), darker coloration of pronotum and elytra medially, more forwardly protruded anterior angles of pronotum (pointing more outward in the pronotum of P. formosana ), and shorter and more divergent posterior angle of pronotum (longer, more robust and nearly straight in P. formosana ). The shape of aedeagus also readily differentiates these two species. Based on the illustration of Ôhira (1972: fig. 3), the distal half of the median lobe of P. formosana has four large acute processes laterally, and its apex is somewhat rectangular; and the paramere of P. formosana has the apex rounded and slightly outward.

Description

(male holotype). Body smooth, surface covered with curved, semi-erect, and moderately long pubescence. Body length 5.9 mm; width 2.2 mm; antenna length 3.0 mm; pronotum length 1.4 mm, pronotum width 1.9 mm (measured at posterior angles), elytra length 3.5 mm.

Body brown, pubescence yellow (Fig. 1A ). Head dark brown, antennae yellowish brown, labrum and mandibles brown, remaining mouthparts yellowish brown. Pronotum dark brown centrally; lateral, anterior and hind portions, and hind angles yellowish brown, with darker outlined margins. Scutellar shield brown, with dark outlined margins, especially anteriorly. Elytra dark brown centrally, yellowish brown laterally; yellowish-brown portions gradually lightened toward apices, basal margins of elytra dark outlined. Underside reddish brown, prosternum darker than hypomeron, sternites VI-VII and legs yellow.

Head including eyes 0.5 times as wide as pronotum. Supra-antennal carinae short, directed mesad and fading medially so that median portion of frontoclypeus is not formed by sharp carina; frontoclypeus overhanging base of labrum in lateral view. Head surface sparsely punctate; punctures small, intervals between punctures mostly equal 2-3 puncture diameters. Maxillary palpus with palpomere III longer than wide. Antenna (Fig. 3E ) surpassing hind angle of pronotum by about one antennomere; scape robust and longest, remaining antennomeres subequal in length; ultimate antennomere obliquely truncate, with apex rounded.

Pronotum (Fig. 3A ) wider than long (measured at midline), widest near middle. In lateral view, pronotum convex. Anterior angles of pronotum protruding (Fig. 3C ); protrusion of anterior angle subquadrate, inner angle more protruded than outer angle, posterior part of protrusion with deep, crescent-shape pit. Lateral margins of pronotum arched medially, sides near middle narrowing anteriad and posteriad, anteriorly narrowing more sharply than posteriorly; posterior angles (Fig. 3F ) long, slightly divergent, apical portion of posterior angle slightly enlarged, then narrowed, apex blunt. Disc of pronotum sparsely covered with small, shallow punctures; intervals between punctures on average subequal to four to six puncture diameters; interstices smooth. Pubescence mostly directed outwards; basal portion directed anteriorly.

Hypomeron (Fig. 3B ) more densely punctate than pronotum, punctures small and shallow, intervals between punctures on average subequal to 3-4 puncture diameters; apex of hypomeron strongly protruded, margin wrinkled. Pronotosternal sutures nearly straight, anterior excavation wide, long carination paralleled with suture from base of hypomeron and reaching anterior protrusion of hypomeron, forming hook-shaped carination anteriorly, end of the carination slightly extending backwards, with a small pit partly enclosed by curving hook of carination (Fig. 3D ). Prosternum (Fig. 3B ) including prosternal process about 2.00 times as long as wide; chin piece with large, dense punctures, intervals between punctures approximately one puncture diameter; punctures in remaining area sparser and smaller, intervals between punctures 3-6 puncture diameters, punctures on prosternal process sparse, small. Prosternal process (Fig. 3H ) with ventral surface horizontal in lateral view, with elongate notch ventroapically, roundly enlarged dorsoapically.

Scutellar shield (Fig. 3F ) suboval, about 1.2 times as wide as long; anterior margin rounded, posterior margin slightly pointed. Mesoventrite (Fig. 3B ) with deep procoxal rests. Mesoventral process elevated, hind margin wide. Mesanepisternum with large, curved lateral extensions of procoxal rests. Metaventrite medially with sparse punctures, intervals between punctures on average subequal to 3-5 puncture diameters. Anterior portion of discrimen with sharp groove, occupying half-length of metaventrite. Metacoxal plate enlarged inward, narrowed laterad (Fig. 3G ), surface with very sparse punctures.

Elytra (Fig. 1A ) elongate, together 1.6 times as long as wide, widest at 1/3 of their length from base. Humeri (Fig. 3A, F ) elevated. Sides from humeri roundly widened to 1/3 of elytral length in dorsal view, then gradually narrowed towards apices; apices slightly independently rounded. Elytral striae shallow, formed by lines of small punctures, intervals between punctures in stria on average subequal to 2-3 puncture diameters. Interstriae flat, smooth, with some micropunctures. Hind wings absent. Abdomen with ventrites more densely punctate than pronotum, intervals between punctures on average subequal to 2-3 puncture diameters; pubescence directed backwards. Apical ventrite with blunt apex. Tergite VIII (Fig. 5C ) subtriangular, 1.6 times as long as wide, distal margin pointed medially, apically covered with sparse pubescence. Sternite VIII with two dark colored lobes, shape as Fig. 5C , with long setae, remaining portion membranous. Tergite IX (Fig. 5B ) subtriangular, 1.3 times as long as wide, medially deeply emarginate; two lobes elongate, lateral sides with long setae; tergite X (Fig. 5B ) membranous, exceeding apices of lobes of tergite IX. Sternite IX (Fig. 5A ) slightly stout, 2.7 times as long as wide, apically widely rounded and setose.

Aedeagus (Fig. 5D-F ) with robust median lobe, two times as long as one paramere; distal half of median lobe arrow-shaped, apex with small protrusion, apex blunt, laterally with small acute projections; long, needle-like sclerite present on ventral side of median lobe. Paramere stout, reaching half of median lobe; apex pointed outward. Phallobase subquadrate, margins thickened, medially with longitudinal thickened line, basal angles rounded.

Female. Unknown.

Immature stages.

Unknown.

Distribution.

China: Taiwan (Chiayi).

Etymology.

The specific patronymic epithet is dedicated to Dr Wen-I Chou (Taiwan, China), the collector of the holotype.

Figures

Figure 1. Habitus of Pseudocsikia spp. A Pseudocsikia choui sp. nov., male holotype, dorsal view B Pseudocsikia chanjuan sp. nov., male holotype, dorsal view. Scale bar: 1.0 mm.

Figure 3. Characters of Pseudocsikia choui sp. nov., male, holotype A pronorum, dorsal view B pro- and mesothorax, ventral view C anterior protrusion of pronotum, dorsal view D anterior protrusion of hypomeron, ventral view E antenna F posterior angle of pronotum, dorsal view G metacoxal plate, ventral view H prosternal process, lateral view. Scale bars: 0.5 mm (A, B, E, F); 0.2 mm (C, D, G, H).

Figure 5. Characters of Pseudocsikia spp. A-F Pseudocsikia choui sp. nov., male holotype G-L Pseudocsikia chanjuan sp. nov., male, holotype A, G abdominal sternite IX, dorsal view B, H abdominal tergites IX-X, dorsal view C, I abdominal sternite VIII and tergite VIII, ventral view D, J aedeagus, ventral view E, K aedeagus, lateral view F, L aedeagus, dorsal view. Scale bar: 0.2 mm.