Chaetocnema (Chaetocnema) purerulea Ruan & Yang & Konstantinov & Prathapan & Zhang 2019, New Species

33. Chaetocnema (Chaetocnema) purerulea Ruan, Konstantinov & Yang, New Species

(Fig. 54)

Etymology: This species is named after its body color. The name is a combination of Latin words ‘purpura’ and ‘caeruleus’ meaning ‘purple’ and ‘blue’ respectively. Specific epithet is a noun in apposition.

Diagnosis: This species is close to C. himalayana and C. duvivieri. It may be distinguished by the shorter antennae, unique frontal ridge decorated with wrinkles and dark purple blue dorsum. It is also close to C. taiwanensis, however, they are entirely different in coloration.

Distribution: India.

Host plants: Unknown.

Description: Body length: 2.50–2.60 mm. Body width: 1.35–1.37 mm. Ratio of length of antenna to length of body: 0.55–057. Ratio of elytron length (along suture) to width (maximum): 2.50–2.60. Ratio of pronotum width (at base) to length: 1.60–1.65. Ratio of length of elytron to length of pronotum (along middle): 2.55–2.60. Ratio of width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.10–1.11.

Dorsum deep purple blue. Dorsum and head smooth, not reticulated. Antennomeres 1–4 yellow, 5–11 dark brown, with apical ones darker. Tarsi and tibiae dark red brown. Pro- and mesofemora dark red brown. Metafemora dark brown.

Head hypognathous. Frontal ridge wide, slightly convex, covered with transverse wrinkles. Frontolateral sulcus present. Suprafrontal sulcus absent, frontal ridge entirely merge with vertex. Orbital, supraantennal sulci deep. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 2.00–2.05. Vertex covered with inconspicuous wrinkles and minute, rugged and sparse punctures. Number of punctures on orbit: 2–3 on each side. Number of punctures on frons (triangular area surrounded by frontolateral sulcus and clypeus): 0. Number of setae on clypeus: approximately 10. Number of setae on labrum: 6. Anterior margin of labrum slightly convex in middle.

Pronotum without longitudinal impressions near basal margin. Deep row of large punctures at base of pronotum absent. Pronotal base evenly convex. Lateral margins of pronotum convex, not conspicuously converging forward. Anterolateral prothoracic callosity rounded, moderately to poorly developed. Posterolateral prothoracic callosity poorly developed. Pronotal punctures tiny and rugged. Diameter of pronotal punctures 3–6 times smaller than distance between adjacent punctures.

Elytra with slightly convex lateral sides. Elytral punctures larger than those on pronotum, arranged in single regular rows, including peri-scutellar row. Elytral interspaces between puncture rows slightly costate at sides. Number of rows of minute punctures on each interspace: 2–3. Humeral callus well developed.

Excavation on metatibia shallow. Large lateral denticle on metatibia obtuse. Metatibial serration proximal to large lateral denticle absent or poorly developed.

Spermathecal receptacle pear-shaped. Spermathecal duct curved. Spermathecal pump much shorter than receptacle, with cylindrical apex. Vaginal palpus slightly narrowing from base till middle, approximately parallel-sided beyond middle.Anterior sclerotization of vaginal palpus slightly widening anteriorly. Posterior sclerotization longer than wide. Posterior sclerotization wider than anterior.

Type: Holotype: ♀ (BMNH), labels: 1) India: Assam, Mishmi Hills, Delai Valley, Taphlogam, 8.xi.1936; 2) Alt. 7400ft, M. Steele, B. M. 1937–324; 3) Chaetocnema purerulea sp. nov. Des. Ruan et al., 2016.