Psammoecus bipunctatus (Fabricius, 1792)

Yoshida, Takahiro & Hirowatari, Toshiya, 2014, A revision of Japanese species of the genus Psammoecus Latreille (Coleoptera, Silvanidae), ZooKeys 403, pp. 15-45 : 21-23

Psammoecus bipunctatus (Fabricius, 1792) Figs 1B, 4and 13 D–F

Notoxus bipunctatus Fabricius, 1792: 212. Type locality: Germania Dom.

Latridius bipunctatus : Herbst 1793: 10.

Anthicus bipunctatus Fabricius, 1801: 291.

Psammoecus bipunctatus : Latreille 1829: 135. - Schaufuss 1916: 457, fig. 4 in pl. 14. - Hetschko 1930: 81. (catalogue) - Halstead et al. 2007 - Hirano 2009: 63, 64, 82, fig. 3. - Hirano 2010: 11, 12.

Psammaechus [sic.] bipunctatus: Smith 1851: 15. (catalogue)

Diagnosis.

This species is similar to Psammoecus trimaculatus and Psammoecus boreas sp. n., but can be distinguished from the former by the shorter teeth on the lateral margins of the pronotum and from the latter by the shorter body length and the shorter antennae.

Description.

Body length. 2.25-2.83 mm (n=9).

Coloration (Fig. 1B). Head dark brown, gradually darker toward anterior. Pronotum yellowish-brown to reddish-brown. Elytra yellowish-brown with round dark maculae on posterior 1/3, elytral suture dark in posterior half. Elytra of lighter colored specimens with reduced dark maculae and dark areas of elytral suture. Antennae yellowish-brown basally, 9th, 10th and posterior end of 8th antennomeres blackish-brown, 11th (apex) yellowish-brown.

Head (Fig. 4A, B, C). Triangular, HW/HL 1.55-2.06; IE/HL 1.03-1.33. Dorsal surface with strong dense punctures, temples and posterior ventral surface also with irregularly dense punctures. Temples well enlarged, immediately narrowing thereafter. Eyes prominent, relatively small. Antennae 1.09-1.20 mm, comparatively thick, short; covered with medium length erect pubescence on each antennomere; approximate ratio of one of examined specimens as follows: 2.6: 1.1: 1.2: 1.1: 1.2: 1.2: 1.1: 1.0: 1.1: 1.0: 1.8 (Fig. 4A).

Pronotum (Fig. 4B, C). Roundly subquadrate, PW/PL 1.16-1.24. Dorsal surface with strong moderately dense punctuation, denser than that on ventral surface; some punctures on ventral surface in rows. Pubescence composed of many short setae on dorsal surface and several medium length setae on each lateral margin, distance between medium length setae approximately regular. Each anterior angle with several very small teeth, each lateral margin with four similarly sized small teeth, the distance between them irregular and variable; each posterior angle with a small tooth, similar in size to those on lateral margins.

Elytra (Fig. 4E). Elongate, EW/BL 0.36-0.47. Rows of punctures almost same width as interstices. Pubescence composed of numerous comparatively short setae, without long setae.

9th abdominal sternite (Fig. 13D). Strut Y-shaped, cut at anterior 1/3, diverging in posterior 1/4, branches relatively wide, ends of each branch pointed and curved inwards. Lateral sclerites elongate, membranous.

Aedeagus (Figs 13E and F). Parameres club-shaped, wide and thick at bases, each apical portion with a long seta, stick-shaped portions with sparse punctuation and several short setae, lateral portions and inner margins of bases with successions of dense punctures, inner margin of bases with numerous short setae. Phallobase enlarged toward posterior margin from posterior 1/3, anterior margin roundly incised, anterior portion extended. Penis flat, wide, narrowed gradually toward apex, apical portion pointed, apical portion of dorsal part with sparse punctures.

Specimens examined.

JAPAN: [Hokkaido Pref.] 1 male, Takkobu-numa Lake, Kushiro City, 1 –IX– 2006, T. Yoshida leg. (ELKU); 1 ex., Iwabokki, Kushiro City, 25 –VIII– 1990, M. Sakai leg. (EUMJ); 6 exs., same locality, 26 –VIII– 1990, M. Sakai leg. (EUMJ); 1 ex., same locality, 29 –VIII– 1990, M. Sakai leg. (EUMJ).

Distribution.

JAPAN: Hokkaido; Africa; Europe; Russia; Turkestan.

Biological notes.

This species is known to inhabit marshland. Warne (1963) reported that large numbers of this species were found on Carex .

Remarks.

The habitat and distribution of this species are unusual in the genus Psammoecus . This species inhabits marshland and is distributed in comparatively high latitudes where species richness of Psammoecus is poor. Coloration is variable. In the past, four aberrations and two varieties (e.g. Lucas 1843; Gerhardt 1912) were described.