Stenelmis ishiharai M. Satô, 1965

Hayashi, Masakazu, Kamite, Yuuki, Kobayashi, Takuya & Sota, Teiji, 2016, Description of larvae of genera Stenelmis, Ordobrevia and Nomuraelmis (Coleoptera: Elmidae: Elminae) of Japan with their molecular taxonomy, Zootaxa 4178 (4), pp. 451-480 : 462

Stenelmis ishiharai M. Satô, 1965

( Figs 2 I–K, 8)

Material examined. JAPAN: Okinawa Prefecture: Ishigakijima Is.: 2 exs., Omoto, Ishigaki-jima , 22.iii.1999, H. Moriya leg. ; 3 exs. (dried with an ultrathin coating of gold) and 4 exs. (in 60% ethanol), Nishihama-gawa (river), Nosoko, Ishigaki-shi , 5.vi.2014, YK leg.; 1 ex. (in 99.5% ethanol), Sakieda, Ishigaki-shi, 2.ii.2011, YK leg.; Iriomotejima Is.: 6 exs. (in 60% ethanol), Aira-gawa, Taketomi-chô, 7.vi.2014, YK leg.

Description. Body elongate, gradually narrowing from middle to apex; convex dorsally and flattened ventrally; slightly prominent spiracles on mesothorax and abdominal segments I–VIII. Body color entirely brown or black, and appendages yellowish brown. Dorsal and ventral surfaces not smooth with minute granules and setae, but last segment smooth on dorsal and ventral surfaces.

Head visible from above, well exposed from prothorax; as wide as long; clypeus transverse, with setae on front; a pair of spines on both sides of clypeus; vertex with granules and brush-like setae.

Thorax not serrated on lateral sides; dorsum with granules and brush-like setae, not entirely smooth. Prothorax longer than width, 2.5 times as long as mesothorax; glabrous spots on basal half; with three ventral sclerites, procoxae closed posteriorly; scale-like setae on hind margins. Meso- and metathorax transverse; metathorax longer than mesothorax. Mesothorax with five ventral sclerites.

Abdomen 9-segmented; segments I–VIII transverse, dorsal surface entirely not smooth with minute granules and setae, brush-like and plumose setae; pleural sclerites on segments I–VII; tergal sutures on dorso-lateral area of segments II–VII but short in VII. Last segment (segment IX) longer than wide, gradually narrowing to apex, without longitudinal ridge, apex with a pair of small spines; dorsal surface smooth but with ramose setae; ventral operculum, opercular claws, and anal gills present.

Habitat. Middle stream reaches; larvae live in the gravel substrate.

Identification. The larva was determined using adult specimens from Ishigakijima Is., because the genus Stenelmis fauna of Ishigakijima includes only S. ishiharai .

Distribution. Ryukyus: Ishigakijima Is. (type locality), Iriomotejima Is.

Bibliography. The larva of this species is newly described in this paper.

Figures

FIGURE 2. Larvae of Stenelmis of Japan. A – C, S. vulgaris Nomura; D – E, S. nipponica Nomura; F – H, S. hisamatsui M. Satô; I – K, S. ishiharai M. Satô. A, D, F, I, dorsal view; B, E, G, J, lateral view; C, H, K, ventral view. Scale bars: 1.0 mm.