Pristosia amaroides Putzeys 1877

Pristosia amaroides (Putzeys, 1877)

Figs. 2, 12, 22, 23.

Catalogue: Calathus amaroides Putzeys, 1877: 103. Type locality: N India, W Bengal, environs of Darjeeling. Calathus amaroides Putzeys: Andrewes, 1934: 218.

Pristosia amaroides (Putzeys): Lindroth, 1956: 552.

Pristosia amaroides (Putzeys): Hovorka & Sciaky, 2003: 530.

Pristosia amaroides (Putzeys): Lorenz, 2005: 400.

Type material: According to the original description two syntypes should exist: 1 male, 1 female, which should be stored at Musée Royal des Sciences Naturelle de Belgique, Bruxelles. During the present study, the type material was not investigated. Species identification is based on additional material from the type locality that H.E. Andrewes already compared with the types (see below). Furthermore, this species is unambiguously distinguishable due to its exceptional character combination.

Additional material: BHUTAN: 1 male, British Bootang, Maria Basti, leg. L. Durel, Ex coll. R. Oberthür, H.E. Andrewes Coll. B.M. 1945-97 (NHML).

INDIA: SIKKIM: 1 female, Gopaldhara, Br. Sikkim, leg. H. Stevens, H.E. Andrewes Coll. B.M. 1945-97 (NHML). WEST BENGAL: 1 female “Darjeeling”, “Bowring 63-47*”, “2612”, “ Calathus amaroides Putz. Compared with type H.E.A.” (NHML); 1 female, Darjeeling, Mungpo, leg. Dr. M. Cameron, B.M. 1931-452 (NHML); 2 females, road from Sandakphu to Golkey, 26.III.1996, leg. Pastica (CSCHM, CWR). NEPAL: ILAM DISTRICT: 1 male, 1 female, [254] Mai Pokhari, 2150–2250 m, 23.–25.VIII.1983, leg. J. Martens & B. Daams (CSCHM, SMNS). PANCHTHAR DISTRICT: 1 male, 1 female, [258] zw. Deorali u. Sheldoti, 2600– 2500 m, Tsuga-Lithocarp., 28.VIII.1983, leg. J. Martens & B. Daams (CSCHM, SMNS). TAPLEJUNG DISTRICT: 1 male, [288a] zw. Amjilesa u. Mündung der Gunsa Khola, 1700 m, Schluchtwald, 13.IX.1983, leg. J. Martens & B. Daams (SMNS); 1 male, [371] Hellok in Tamur Valley, 2000 m, forest remnant, bushes, 17.V.1988, leg. J. Martens & W. Schawaller (SMNS). THERATUM DISTRICT: 1 female, Kosi Prov., Basantapur, 2190 m, 27°11N 87°27E (GPS), 22.–23.VI.2000, leg. J. Farkac, D. Král & J. Schneider (NHMB).

Redescription: 13 specimens studied.

Body length: 10–11 mm.

Colour: Dorsal and ventral surface of body and femora dark brown, pronotal lateral margin, knees, tibiae, tarsi, antennae and palpi lightened to yellowish brown, elytral surface slightly greenish or bluish metallic.

Microsculpture: Head with mesh pattern isodiametric, weakly engraved, pronotum and elytra with very weakly engraved transverse meshes, visible under high magnification (120x).

Head: Temporae about 2/5 of eye diameter.

Pronotum: Ratio PW/PL 1.28–1.39, PW/HW 1.81–1.90. Laterobasal impressions often with suggestion of a puncture in middle. Lateral setae located beside internal border of lateral gutter, and basolateral seta located distinctly removed from lateral edge (4–5 times pore diameter) and distinctly distant from basal edge (3–4 times of pore diameter).

Elytra: Ratio EL/EW 1.43–1.57, EW/PW 1.22–1.24. Basal groove forming a right angle with scutellar stria and an acute angle with lateral groove.

Male genitalia: Aedeagal median lobe, in dorsal view, relatively broad with sides convex and apical lamella remarkably short (Fig. 22). Internal sac very characteristic: In dorsal view, with a vesicular fold in median lobe middle and several longitudinal folds extending toward median lobe apex; two of the latter are distinctly more sclerotized, narrow lanceolate, and proceeding evenly and slightly arcuate on right side of ostium (Fig. 22).

Identification: Pristosia amaroides differs from all other Himalayan species by having an Amara -like body form, which means that pronotal sides are widest near base, elytral sides are only slightly restricted toward base, pronotal and elytral discs are only moderately convex, and pronotal front angles are wrinkled and distinctly protruded anterad. Moreover, the species differs by slightly metallic surface of elytra, by the metafemur without setae on ventral surface, and by a very characteristic internal sac folding.

Distribution: Fig. 42. Southern slopes of Eastern Himalaya from Eastern Nepal to Bhutan.

Habitat: This species inhabits subtropical and meridional broadleaved forests of the lower montane zone and lower cloud forest zone (“Untere Montanstufe” and “Untere Nebelwaldstufe” after Miehe 1991) at altitudes between approximately 1700–2500 m.