Psammoecus triguttatus Reitter, 1874

Yoshida, Takahiro & Hirowatari, Toshiya, 2014, A revision of Japanese species of the genus Psammoecus Latreille (Coleoptera, Silvanidae), ZooKeys 403, pp. 15-45: 25-27

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Psammoecus triguttatus Reitter, 1874


Psammoecus triguttatus Reitter, 1874   Figs 1D, 6and 13 J–L

Psamoecus triguttatus   [sic.] Reitter, 1874: 524. Type locality: Japan; Type deposition: the Natural History Museum, London; Type examined. (misspelling)

Psammoecus triguttata   [sic.]: Hisamatsu 1982: 16.

Psammoecus triguttatus   : Hetschko 1930: 82. (catalogue) - Kamiya 1961: 18, pl. 5. - Sasaji 1985: 204, fig. 33 in pl. 32. - Halstead et al. 2007


This species is closely similar to Psammoecus trimaculatus   and Psammoecus labyrinthicus   sp. n. Morphological differences among these species were stated in diagnosis of Psammoecus trimaculatus   .

Description. Body length. 2.32-2.93 mm (n=23).

Coloration (Fig. 1D). Head and pronotum yellowish-brown to reddish-brown. Elytra yellowish-brown with variable dark maculae: round ones at half, oval ones on the posterior half to posterior 1/4 of elytral suture, sometimes connected with maculae at half, darkened around end of elytra. Antennae reddish-brown basally, blackish-brown from 8th to 10th antennomeres, 11th (apex) comparatively bright.

Head (Fig. 6A, B, C). Triangular, HW/HL 1.46-1.90; IE/HL 0.92-1.20. Temples slightly expanded behind eyes, narrowed toward posterior. Eyes large, prominent. Dorsal surface with relatively dense punctuation. Antennae 1.06-1.38 mm, moderately long; covered with considerable medium length or long semi-erect setae and short pubescence on each antennomere; approximate ratio of lectotype as follows: 2.7: 1.0: 1.1: 1.2: 1.3: 1.3: 1.3: 1.1: 1.1: 1.1: 2.0 (Fig. 6A).

Pronotum (Fig. 6B, C). Broad, PW/PL 1.31-1.50. Dorsal surface with relatively dense punctuation. Pubescence composed of relatively fine short or medium length setae, a long seta on each tooth on lateral margins and anterior and posterior angles. Each anterior angle with four or five small teeth; each lateral margin with four teeth, tooth I small, tooth II longer than tooth I, teeth III and IV relatively narrow and of almost identical size, longer than tooth II, tooth V smallest or absent; each posterior angle with a few very small protuberances of variable shape.

Elytra (Fig. 6E). Elongate-oval, EW/BL 0.39-0.45. Rows of punctures narrower than interstices. Pubescence composed of many semi-erect setae of medium length; several long setae in a row around anterolateral margins.

9 th abdominal sternite (Fig. 13J). Strut Y-shaped, cut at anterior 2/5. Lateral sclerites curved inward, relatively elongate.

Aedeagus (Fig. 13K, L). Parameres club-shaped, wide around bases, posterior inner margins of wide portions a little prominent, punctuation on narrow portions relatively sparse, a little denser on wide portions, posterior half of inner margins of wide portions with many setae, narrow portions with several sparse setae, apex with a long seta. Posterior half of phallobase wider towards posterior margin, distance between posterior margin and deepest point of incision of margin of upper layer narrow, protuberances around anterior 1/4 pointed inwards, posterior margin of lower layer widely deeply incised. Penis relatively flat and thin, narrowed toward apex, punctuation around apex denser toward apex.

Type series.

Lectotype: male, Nagasaki, Nagasaki Prefecture, Japan, 1869, G. Lewis leg. (BMNH). Paralectotype: 1 female, same locality, 1869, G. Lewis leg. (BMNH). (here designated)

Specimens examined.

JAPAM: [Tokyo Pref.] 1 male, Hatagaya, Shibuya-ku, 30 –VII– 1956, K. Tanaka leg. (EUMJ). [Gifu Pref.] 1 male, Tentoku, Toki-chô, Mizunami City, 6 –VIII– 2010, K. Itô leg. (ELKU); 1 male, Konokure, Toki-chô, Mizunami City, 16 –VII– 2011, K. Itô leg. (ELKU). [Kagoshima Pref.] 1 male, 4 females and 3exs., Sata Cape, Minamiôsumi Town, 6 –VII– 1968, K. Suga leg. (HUSE); 1 male, Nakanoshima Island, Toshima Village, 9 –VII– 1969, M. Satô leg. (EUMJ); 1 male, same locality, 26 –VI– 1965, S. Fukuda leg. (HUSE). [Okinawa Pref.] 1 male, Aha beach, Kunigami Village, Okinawa Island, 23 –I– 2008, Y. Hirano leg. (YHC); 2 males and 2 exs., Motobu Town, Okinawa Island, 19 –VIII– 2008, T. Yoshida leg. (ELKU); 1 male, Fusato, Nanjô City, Okinawa Island, 5 –VI– 1970, M. Takagi leg. (EUMJ); 1 male, Mt. Omoto-san, Ishigaki Island, 1 –VII– 1965, Y. Hori leg. (EUMJ); 1 male, Ushuku-no-mori, Iriomote Island, 26 –VI– 1965, Y. Hori leg. (EUMJ).


JAPAN: Honshu, Kyushu, Nakanoshima (Tokara Islands), Okinawa, Ishigaki and Iriomote Islands.


Psammoecus   sp. 4 illustrated by Hirano (2009) and Hirano (2010) seems to be this species or Psammoecus labyrinthicus   sp. n. However, identification is difficult, because the specimen is a female. The Japanese name of Psammoecus   sp. 4 given by Hirano (2009) and Hirano (2010) “Nise-mitsumon-semaru-hiratamushi” is adopted as the Japanese name of this species in this paper.

Halstead et al. (2007) recorded distribution of this species from Russia (Far East), Korea, China and Japan. However, it is now clear that at least two closely similar species occur in Japan, so, past records of this species should be reconfirmed. In addition, two or more closely similar species were sometimes found in the same limited area such as Tentoku, Toki-cho, Mizunami City, Gifu Prefecture where Psammoecus triguttatus   and Psammoecus trimaculatus   were collected. Thus, these species should be identified carefully.

Syntypes of this species consist of two specimens, one male and one female. The male specimen is designated as a lectotype, and the female specimen is designated as a paralectotype.