Zaitzeviaria ovata (Nomura, 1959)

Hayashi, Masakazu & Kamite, Yuuki, 2020, Description of larvae of Japanese Macronychini (Coleoptera: Elmidae: Elminae), Zootaxa 4859 (2), pp. 195-227 : 202-204

Zaitzeviaria ovata (Nomura, 1959)

( Figs 1D , 6 , 18E , 20C )

Materials examined. JAPAN: [HONSHU]: 7 larvae, Miyama-gawa, Manda, Izumo-shi , Shimane Pref., Honshu , 23.xii.2017, M. Hayashi leg. 2 larvae, Inu-dani, Nishihayashigi, Izumo-shi , Shimane Pref., Honshu , 20.i.2018, 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. 6D : 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; 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. 18E ). 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 with minute granules and coarse granules sparsely; without ridge on both sides ( Fig. 6E ); with longitudinal ridge on meson; apex truncate and slightly dentate; ventrally flat, with subpentagonal-shaped operculum, opercular claws, and anal gills.

Habitat. Headwaters to upper stream reaches; larvae live in the gravel and/or sand substrate.

Identification. The larva was identified by mitochondrial DNA sequences ( Hayashi & Sota 2010).

Distribution. Hokkaido, Honshu (type locality), Shikoku, Kyushu, Sado Is., Goto Isls.

Bibliography. Hayashi & Sota (2010: fig. 13).

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 6. Zaitzeviaria ovata (Nomura, 1959). A–C, Head and prothorax; 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.