Byctiscus ivanovi Legalov, 2021

Legalov, Andrei A., 2021, A new species of the genus Byctiscus Thomson, 1859 (Coleoptera, Rhynchitidae) from Vietnam, Baltic Journal of Coleopterology 21 (2), pp. 169-174 : 170-173

Byctiscus ivanovi Legalov , sp. nov.

( Fig. 1)

Type material: Holotype. Male ( ISEA), Vietnam, near Lai Chau, IV.2021, local collector . Paratype. Female ( ISEA), idem .

Description. Male. Body blue-green, covered with very fine light hairs. Apex, sides, and bottom of rostrum, antennomeres 1-8, sides of pronotum, elytra, trochanters, partially femora and tibiae, and tarsi blue. Back of rostrum, forehead, basal part of vertex, head ventrally, disk of pronotum, prosternum, meso- and metaventries, metepisternum, abdomen, coxae, partially femora and tibiae green. Four spots on elytra aureate. Rostrum long, 2.8 times as long as wide at apex, 4.0 times as long as wide in middle and at base, 1.1 times as long as pronotum, distinctly curved, finely and densely punctate, with weak carina in middle and basal thirds. Antennal scrobes long, sulciform. Antennae inserted after rostrum middle. Forehead quite narrow, 0.9 times as narrow as rostrum base width, flat, punctate. Eyes almost not protruding from contour of head. Vertex sparsely punctate. Temples 1.1 times as long as eyes, transverse-rugose. Antennae long, reaching base of pronotum. Antennomeres 1 and 2 suboval, equal in wide. Antennomere 1 1.8 times as long as wide at apex. Antennomere 2 1.5 times as long as wide at apex, 0.8 times as long as antennomere 1. Antennomeres 3- 5 subconical. Antennomere 3 1.4 times as long as wide at apex, 0.9 times as long as and 0.9 times as narrow as antennomere 2. Antennomere 4 2.0 times as long as wide at apex, 1.3 times as long as and 0.9 times as narrow as antennomere 3. Antennomere 5 1.8 times as long as wide at apex, equal in length as and 1.1 times as wide as antennomere 4. Antennomeres 6-8 subequal in length. Antennomere 6 rounded, 1.1 times as long as wide in middle, 0.7 times as long as and 1.1 times as wide as antennomere 5. Antennomeres 7 and 8 wide-conical, transverse. Antennomere 7 0.9 times as long as wide at apex, 1.3 times as wide as antennomere 6. Antennomere 8 0.8 times as long as wide at apex, 1.1 times as wide as antennomere 7. Club wide and lose, 0.8 times as long as antennomeres 1-8 combined. Antennomere 9 0.9 times as long as wide at apex, 1.8 times as long as and 1.5 times as wide as antennomere 8. Antennomere 10 subequal in length and width, 1.1 times as long as and equal in width to antennomere 9. Antennomere 11 1.6 times as long as wide at base, 1.3 times as long as and 0.8 times as narrow as antennomere 10. Pronotum transverse, campaniform, 1.4 times as long as wide at apex, 0.8 times as long as s wide in middle, subequal to wide at base, narrowed to apex, lustrous, finely punctuate, with rounded sides. Greatest width in middle. Scutellum trapezoid, wide, 0.5 times as long as wide. Elytra wide, 1.4 times as long as wide at base, 1.3 times as long as wide in middle, 1.4 times as long as wide at apical fourth, 2.5 times as long as pronotum, with distinct humeri. Interstriae quite wide, 2.0- 2.5 times as wide as striae, weakly convex, lustrous, finely punctate. Scutellar striole present. Striae narrow. Points in striae distinct and small. Epipleuron distinct.

Legalov A.A.

Prosternum punctate, with tooth. Precoxal portion of prosternum 0.5 times as long as procoxal cavity. Postcoxal portion of prosternum short, about 0.2 times as long as procoxal cavity. Procoxal cavities contiguous. Mesocoxal cavities narrowly separated. Metepisternum wide, 2.4 times as long as wide in middle, finely punctate. Metaventrite subequal in length to length of metacoxa, weakly convex, punctate. Abdomen convex ventrally, punctate. Ventrites 1-3 subequal in length. Ventrite 1 0.6 times as long as length of metacoxa. Ventrite 4 0.8 times as short as ventrite 3. Ventrite 5 0.4 times as long as ventrite 4. Pygidium convex, finely punctate. Legs long. Procoxae subconical. Femora weakly widened. Tibiae weakly expanded to apex, with apical spur. Protibiae almost straight lines. Meso- and metatibiae weakly biconcave. Tarsi quite long. Tarsomere 1 conical. Tarsomere 2 wide-conical. Tarsomere 3 bilobed. Tarsomere 5 elongate. Claws with teeth. Total body length (without rostrum) 7.1 mm. Length of rostrum 1.9 mm. Female. Rostrum shorter, 2.4 times as long as wide at apex, 3.1 times as long as wide in middle and at base, 1.1 times as long as pronotum, weakly curved. Pronotum 1.2 times as long as wide at apex, 0.7 times as long as s wide in middle, 0.8 times as long as wide at base, with weakly rounded sides. Elytra 1.3 times as long as wide at base, 1.2 times as long as wide in middle, 1.5 times as long as wide at apical fourth, 2.8 times as long as pronotum. Prosternum without tooth. Total body length (without rostrum) 7.1 mm. Length of rostrum 1.7 mm.

Diagnosis. This new species is similar to B. fukienensis from China but differs in the other form of the basal sclerite, sparsely punctate pronotum, and the blue-green body.

Etymology. The species is named in late Dr. Alexander V. Ivanov (Yekaterinburg, Russia).

Distribution. Northwest Vietnam.