Ordobrevia amamiensis (Nomura 1957)

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 : 470-473

Ordobrevia amamiensis (Nomura 1957)

( Figs 4 A–F, 14)

Materials examined. JAPAN: Okinawa Prefecture: Okinawajima Is.: 1 ex. (in 99.5% ethanol), Ôura-gawa (river), Ôkawa , Nago-shi , 18.v.2007, YK leg.; Kumejima Is.: 2 exs. (dried with an ultrathin coating of gold) & 2 exs. (in 60% ethanol), Shirase-gawa-jyoryǔ (river), 19.v.2007, YK leg.; 1ex (in 60% ethanol), Darumayama , Kumejima-chô , 20.ii.2016, YK leg.; Iriomotejima Is.: 1 ex. (dried), Ôhara , 20.iii.1999, H. Moriya leg. ; 1 ex. (in 60% ethanol), Aira-gawa (river), 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 yellowish brown or orange, sometimes black, and appendages yellowish brown. Dorsal surface not smooth with dense minute granules and setae.

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 minute granules and brush-like setae.

Thorax not serrated on sides; dorsal surface entirely not smooth with granules and dendritic setae. Prothorax longer than width, 2.5 times as long as mesothorax; with three ventral sclerite, procoxae closed posteriorly; scalelike setae on hind margins. Meso- and metathorax transverse; metathorax longer than mesothorax. Mesothorax with five ventral sclerites.

Abdomen 9-segmented. Segments I–VIII transverse, dorsum entirely not smooth with dendritic setae, ventral surface smooth and shiny with setae sparsely; pleural sclerites on segments I–VII; tergal sutures on dorso-lateral area indistinct. Last segment (segment IX) longer than wide, robust in base, narrowing to apex without longitudinal ridge; dorsal surface not smooth with sharp spines and dendritic setae; ventral surface smooth and shiny; apex with a pair of spines; ventral operculum, opercular claws, and anal gills present.

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

Identification. The larva of this species was determined from specimens from Iriomote Is. because the Ordobrevia fauna of Iriomote includes only O. amamiensis . This type of larvae, accompanied with adults of O. amamiensis , is collected from Amami-Ôshima Is., Okinawajima Is., Kumejima Is and Iriomotejima Is.

Distribution. Ryukyus: Amami-Ôshima Is. (type locality), Okinawajima Is. (type locality of subsp. okinawana Nomura), Iheyajima Is., Kumejima Is. (new record), Iriomotejima Is. (new record).

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

Figures

FIGURE 4. Larvae of Ordobrevia and Nomuraelmis of Japan. A – F, O. amamiensis (Nomura) (A – C, immature larva from Amami-Ôshima Is.; D – F, mature larva from Iriomotejima Is.); G – L, N. amamiensis M. Satô (G – I, mature larva from Amami- Ôshima Is.; J – L, immature larva from Okinawajima Is.).