Pristosia atrema Andrewes 1926
Creators: name: Schmidt, Joachim
name: Hartmann, Matthias
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Pristosia
Pristosia atrema

description: Pristosia atrema (Andrewes, 1926)
Figs. 13, 26–29.
Catalogue: Calathus atrema Andrewes, 1926: 77. Type locality: N India, Kumaon Himalaya, Uttaranchal district, Gori Valley, Burphu, ca. 3500 mNN.
Pristosia atrema (Andrewes): Lindroth, 1956: 551.
Pristosia atrema (Andrewes): Hovorka & Sciaky, 2003: 530.
Pristosia atrema (Andrewes): Lorenz, 2005: 400.
Type material: Holotype male, with label data ” Type ” (round and red bordered printed label), “Burphu Gori- V., 11500 ft. India. H.G.C.”, “G.C. Champion Brit. Mus. 1925-42 ”,“ Calathus atrema Type Andr. H.E. Andrewes det.” (the latter handwritten by H.E. Andrewes) (NHML).
Paratypes: 2 females with same label data as holotype, but “ Paratype ” (round and yellow bordered printed label), and one specimen “ Calathus atrema Cotype Andr. H.E. Andrewes det.” (the latter handwritten by H.E. Andrewes) (NHML).
Additional material: INDIA: UTTARANCHAL DISTRICT: 1 male, with label data “Pindar Valley, 8–11,000 ft. Kumaon. H.G.C.”, “H.E. Andrewes Coll. B.M. 1945-97.” (NHML).
Redescription: Four specimens studied.
Body length: 10.1–10.5 mm.
Colour: Dorsal and ventral surface of body and most parts of femora dark brown, upper anterior side of femora, tibiae, tarsi, antennae and palpi yellowish brown. Male dorsal surface shiny throughout; female shiny on head and pronotum but with elytra dull.
Microsculpture: Head with mesh pattern isodiametric, moderately engraved, and pronotum with very weakly engraved transverse meshes, visible under high magnification (100x). Meshes of microsculpture on elytra in male weakly engraved, slightly transverse; in female isodiametric and much more deeply engraved, and scale-like in anterior 2/3.
Head: Temporae about half of eye diameter. Antennomeres I–III completely smooth except for primary apical setation.
Pronotum: Slightly transverse (ratio PW/PL 1.08–1.12, PW/HW 1.51–1.57). Base distinctly wider than anterior margin. Sides evenly rounded in anterior 3/4 but concave in posterior quarter, hind angles almost rectangular (95–100°) (Fig. 13). Base almost straight in middle, slightly bent anteriorly toward hind angles. Lateral gutter slightly expanded toward base. Basolateral seta located somewhat distant (1–2 times pore diameter) from lateral edge.
Elytra: Oval, with relatively wide shoulders, ratio EL/EW 1.47–1.53, EW/PW 1.41–1.47. Basal groove strongly concave, forming an almost right angle with scutellar stria and a slightly obtuse angle with lateral groove.
Legs: Relatively stout.
Male genitalia: Aedeagal median lobe relatively small, in lateral view almost straight toward apex, but with apical lamella slightly bent down, and with terminal bead not angular (Figs. 27, 29). In dorsal view, apical lamella thin and moderately long. Internal sac folding as in Figs. 26, 28.
Identification: Within the fauna of Kumaon and Nepal Himalaya P. a t re m a differs from other Pristosia species by the combination of characters of pronotal and elytral shape, elytral chaetotaxy and form of aedeagal median lobe. P. championi is a species of sympatric distribution, and has a similar pronotal shape, but has a smaller pronotal base with hind angles more obtuse, has elytra narrower at shoulders and has usually two dorsal setiferous pores in interval III. In addition, the aedeagal median lobe is much more elongated. P. dahud Morvan, 1994, P. g l a b e l l a sp. n., and P. similata sp. n., all from western Nepal Himalaya, are darker in colour of body, have legs more slender, pronotal posterior angles rounded, aedeagal median lobe larger with terminal bead of apical lamella more protruded dorsally, and with different form of internal sac folding (see Figs. 24, 30–40). Both the species P. leptodes Andrewes, 1934, and P. brancuccii Deuve, Lassalle & Quéinnec, 1985, which have a more western distribution in the Kumaon Himalaya, are easily distinguished in pronotal shape, too, because sides are convexly rounded throughout and posterior angles are strongly obtuse (for the latter see Deuve et al. 1985: p. 78, Fig. 3). In addition, P. leptodes is a smaller species (body length 6.5–7 mm), has usually 2 setiferous pore punctures in elytral interval III, and terminal lamella of aedeagal median lobe more strongly angular (see Lindroth 1956: p. 550, Fig. 31 H).
Distribution and geographical variation: P. a t re m a seems endemic to the Nanda Devi massif of Kumaon Himalaya. The species is currently only known from the Gori Valley on SE slope of Nanda Devi which is located close to the Indian-Nepalese border, and from the Pindar Valley on SW slope of Nanda Devi massif. Based on the material studied, the two populations slightly differ in aedeagal characters: The single male specimen from Pindar valley has the median lobe distinctly slenderer and the internal sac more strongly sclerotized before median lobe apex (see Figs. 28, 29). According to these differences, P. a t re m a seems to be a polytypic species, but more material from additional localities needs to be studied before taxonomical conclusions can be drawn.
Habitat: During original description and subsequent species group revisions (Andrewes 1926, 1934, Lindroth 1956) no notes about species habitat where given. However, during the last decade three closely related species were frequently found in the adjacent Nepal Himalaya. These species probably have similar if not identical habitat preferences (see below for further details).
description: Published as part of Schmidt, Joachim & Hartmann, Matthias, 2009, Pristosia Motschulsky, 1865 from the Nepal Himalaya: Taxonomy and Biogeography (Coleoptera: Carabidae: Sphodrini), pp. 1-26 in Zootaxa 2009 on pages 10-12, DOI: 10.5281/zenodo.185751