Shairella Chûjô

Lee, Chi-Feng & Beenen, Ron, 2017, Revision of the genus Shairella Chûjô, 1962 (Coleoptera: Chrysomelidae: Galerucinae) from Taiwan, with descriptions of five new species, Zootaxa 4268 (4), pp. 489-507 : 491-492

Genus Shairella Chûjô

Shairella Chûjô, 1962: 101 (type species: Shairella aeneipennis Chûjô, 1962 , by original designation).

Description. Body size small (length 4.3–7.3 mm), shape oval, convex. General color shining black; antennomeres VII and VIII white, sometimes extending to IX and X.

Head. Labrum transverse, with rounded anterior angles, anterior margin concave, dorsally with few setigerous punctures. Frontal tubercles subtriangular, with anterior angles divergent, basally separated from frons by impressed line. Interocular space wide, 3.2–3.3 times as wide as transverse diameter of eye. Interantennal space 1.2–1.3 times as wide as transverse diameter of antennal socket. Eyes small. Vertex wide, moderately convex and glabrous. Antennae with 11 antennomeres, as long as or slightly longer than body.

Pronotum transverse, about 1.9–2.0x as wide as long. Anterior margins broadly concave, posterior margin truncate or slightly concave, lateral margins posteriorly narrowed. Only lateral margins widely bordered; all margins without setae. Each angle bearing one setigerous puncture and a long pale seta. Surface glabrous, indistinctly finely punctate, with a pair of distinct depressions laterally. Scutellum large, subtriangular.

Elytra convex, posteriorly widened, widest near apex, with punctation sparse and randomly arranged; without setae except several minute setae along longitudinal ridge. One distinct ridge arising from humerus, longitudinal, reduced before apical 1/3. Epipleura slender, gradually narrowed apically, and disappearing before apices. Brachelytrous. Hind wings absent.

Legs slender, apices of all tibiae lacking spines. First metatarsomere elongate, 1.2x as long as following two tarsomeres combined. All claws normal and appendiculate. Procoxal cavities closed, intercoxal prosternal process wide, not elevated, visible between procoxae. Posterior margin of last ventrite with short distinct incisions in male, central lobe evenly rounded and flat, disc largely and triangularly depressed.

Aedeagus slender, parallel-sided, apically narrowed, moderately curved in lateral view; with one longitudinal endophallic sclerite, with one cluster of setae at basal 1/3, and basally bifurcate.

Females. Abdomen with last ventrite truncate or slightly convex or notched (in S. tsoui sp. nov.). Spermatheca slender, as wide as pump, hardly separated from pump; pump wide and strongly curved, apex widely rounded, apex with transverse, short sclerite, size variable; proximal spermathecal duct hardly separated from receptacle, apically narrowed. Gonocoxae longitudinal, conjoined from base to middle, slightly narrowed at apical 1/3, apices rounded, each gonocoxa with seven to nine elongate setae. Ventrite VIII with only apical area and spiculum sclerotized; with dense elongate setae inside apical sclerotized area, apical margin rounded; spiculum elongate and wide.

Diagnosis. The genus Shairella is among the genera classified by Wilcox (1971 –1975) in the section Adoxiites, characterized by the wide pronotum in combination with the unmargined basal border. It is similar to Shaira Maulik, 1936 but apart from the characters mentioned before, all species in Shairella have the humerus raised, whereas it is flat in Shaira . Also, the procoxal cavities in Shaira are open whereas they are closed in Shairella . The genus Khasia Jacoby, 1899 (type species Khasia kraatzi Jacoy, 1899 ) is characterized by a square pronotum which seems elongate due to the strong constriction in the basal half. Moreover, Khasia species are small species with complete elytra that bear relatively long bristles.

Biology. Shairella species appear to be univoltine based on field observations (unpublished data TCRT). Larvae are diurnal and found on the host plant’s leaves during late February. They are easily discovered when feeding on the tops of leaves during the day ( Fig. 1 E). Larval development takes about one month, based on laboratory rearing. Mature larvae leave the host plant and burrow into the soil where they build underground chambers for pupation. Pupal stage ( Fig. 1 F) duration is about 20 days, and adults begin to emerge after early April. Adults are nocturnal and have been observed in the field from May to August.

Distribution. Endemic to Taiwan.

Figures

FIGURE 1. Field photography. 1 A. Male of Shairella guoi sp. nov. feeding on Clinopodium laxiflorum var. taiwanianum; 1 B. Flowers of Clinopodium laxiflorum var. taiwanianum; 1 C. Strobilanthes flexicaulis; 1 D. Hemiboea bicornuta; 1 E. Larva of S. guoi sp. nov. feeding on leaves of Strobilanthes flexicaulis; 1 F. Pupa of S. guoi sp. nov.; 1 G. Adult of Medythia suturalis; 1 H. Adult of Japonitata quadricostata.