Zaitzeviaria sotai Hayashi & Yoshitomi, 2015

Hayashi, Masakazu & Kamite, Yuuki, 2020, Description of larvae of Japanese Macronychini (Coleoptera: Elmidae: Elminae), Zootaxa 4859 (2), pp. 195-227 : 211-218

Zaitzeviaria sotai Hayashi & Yoshitomi, 2015

( Figs 1G , 9 , 18H , 20F )

Materials examined. JAPAN: [OKI]: 4 larvae, Nibu, Chibu-mura, Shimane Pref., Chiburi Island , Oki Islands , 10.v.2013, M. Hayashi leg. 8 larvae, Hobomi, Ama-chô, Shimane Pref., Nakanoshima Island , Oki Islands , 14.v.2015, M. Hayashi leg.

Description. Body length of mature larva ca. 3.0 mm in expanded specimen.

Body elongate, narrowing from thorax to apex; convex dorsally and flattened ventrally; subtriangular in cross section; spiracles on mesothorax and abdominal segments I–VIII. Body color light brown to brown, and appendages yellowish brown. Dorsal and ventral surfaces not smooth with minute flat granules ( Fig. 9B, D ; Kodada et al. 2016: 583) and various types of setae.

Head visible from above, well exposed from prothorax; as wide as long; clypeus transverse, setose; without a pair of spines on both sides of clypeus (frontal tooth); vertex rugose with brush-like setae and minute granules; eyes large but lens of stemmata absent. Antenna with three antennomeres; antennomere 1 shorter than antennomere 2, with short branched setae; antennomere 2 with long sensorial appendage; antennomere 3 short with small sensorial appendage. Maxillae and labium forming a unit (maxillolabial unit). Maxilla with three palpomeres; cardo small; stipes large; galea and lacinia separate, setose apically. Labium narrow with two palpomeres; ligula short and transverse; mentum long; submentum short and transverse.

Thorax not serrated on lateral sides; dorsum entirely not smooth with granules and simple long setae ( Fig. 18H ). Prothorax wider than long, 2 times as long as mesothorax; with glabrous areas on basal half; with seven ventral sclerites (one between coxae, two anteromedial, two anterolateral, and two posterolateral), procoxae not closed posteriorly; flat feather-like setae on hind margins. Meso- and metathorax transverse; metathorax slightly longer than mesothorax. Meso- and metathorax with five ventral sclerites (one large anteromedial, two anterolateral, and two posterolateral).

Abdomen 9-segmented; segments I–VIII transverse, dorsal surface entirely not smooth with coarse and minute granules; pleural sclerites on segments I–VII. Last segment (segment IX) longer than wide, gradually narrowing to apex; tergal surface not smooth without ridge on both sides ( Fig. 9E ); with longitudinal ridge on meson; apex truncate and slightly dentate; ventrally flat, with subpentagonal-shaped operculum, opercular claws, and anal gills.

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

Identification. The larva was identified by association with adult Z. sotai from Chiburi-jima Island (Oki Islands in Sea of Japan), because the Zaitzeviaria fauna of the islands includes only Z. sotai ( Hayashi and Yoshitomi 2015) .

Distribution. Honshu (Shimane and Tottori Pref.), Kyushu (Fukuoka and Oita Pref.), Oki Isls. (Dogo, Nishinoshima, Nakanoshima: type locality, Chiburi).

Bibliography. Hayashi & Yoshitomi (2015: fig. 14).

Figures

FIGURE 1. Macronychini larvae of Japan. A, Sinonychus tsujunensis Yoshitomi & Nakajima, 2012; B, Paramacronychus granulatus Nomura, 1958; C, Zaitzeviaria gotoi (Nomura, 1959); D, Zaitzeviaria ovata (Nomura, 1959); E, Zaitzeviaria brevis (Nomura, 1958); F, Zaitzeviaria kuriharai Kamite, Ogata & Satô, 2006; G, Zaitzeviaria sotai Hayashi & Yoshitomi, 2015; H, Zaitzevia elongata Nomura, 1962. Scale bar = 1.0 mm.

FIGURE 9. Zaitzeviaria sotai Hayashi & Yoshitomi, 2015. A, C, Head and prothorax; B, D, prothorax; E–H, last abdominal segment. A, B, E, lateral view; C, D, F, G, dorsal view; H, ventral view.

FIGURE 18. Flat granules and setae on prothorax. A, Podonychus gyobu Yoshitomi & Hayashi, 2020; B, Sinonychus tsujunensis Yoshitomi & Nakajima, 2012; C, Paramacronychus granulatus Nomura, 1958; D, Zaitzeviaria gotoi (Nomura, 1959); E, Zaitzeviaria ovata (Nomura, 1959); F, Zaitzeviaria brevis (Nomura, 1958); G, Zaitzeviaria kuriharai Kamite, Ogata & Satô, 2006; H, Zaitzeviaria sotai Hayashi & Yoshitomi, 2015.

FIGURE 20. Living larvae. A, B, Paramacronychus granulatus Nomura, 1958; C, Zaitzeviaria ovata (Nomura, 1959); D, Zaitzeviaria brevis (Nomura, 1958); E, Zaitzeviaria kuriharai Kamite, Ogata & Satô, 2006; F, Zaitzeviaria sotai Hayashi & Yoshitomi, 2015; G, Zaitzevia awana (Kôno, 1934); H, I, Zaitzevia rivalis Nomura, 1963; J, Zaitzevia tsushimana Nomura, 1963. Not to scale. H, immature larva; others, mature larva.