Copelatus japonicus Sharp, 1884

Alarie, Yves, Michat, Mariano C., Watanabe, Kohei, Shaverdo, Helena, Wang, Liang-Jong & Watts, Chris H. S., 2022, An outlook on larval morphology of Copelatinae diving beetles with phylogenetic considerations (Coleoptera: Adephaga, Dytiscidae), Zootaxa 5175 (2), pp. 151-205 : 168-169

Copelatus japonicus Sharp, 1884

Source of material. The four instar III larvae studied were associated with adults collected at the following locality: Taiwan. Taipei, Beitou, 24.VIII.1994; L.J. Wang leg. The identification is firm as C. japonicus is the only Copelatus species collected at this locality.

Diagnosis (instar III). The third instar of Copelatus japonicus can easily be distinguished from that of the other species studied in this paper by the following combination of characters: HL = 0.90 mm; L3 <2.00 mm; U <0.40 mm; head capsule rounded, strongly constricted at level of occipital region ( Fig. 21 ), scale-like sculpticels present over frontoclypeus and parietale; anterior margin of frontoclypeus narrowly convex, extending mesally at about level of adnasalia ( Fig. 21 ); adnasalia margined with bluntly rounded and truncated teeth ( Fig. 63 ); MP2/MP1> 1.50; GA/ MP1> 1.50; 1.30 <LP2/LP1 <1.90; inner margin of stipes lacking a dorsal linear row of spinulae; profemur with less than 3 PV and 4 AV secondary setae; metafemur with less than 3 AV secondary setae; urogomphus composed of two urogomphomeres; U/HW <0.40; U/LAS <0.50; Palaearctic.

Description, instar III ( Figs 21–24 , 63 )

Body: Measurements and ratios aimed to characterize body shape are shown in Table 6.

Head ( Figs 21 , 63 ): Head capsule rounded, strongly constricted at level of occiput; anterior margin of frontoclypeus narrowly convex, extending mesally at about level of adnasalia; scale-like sculpticels well-developed over frontoclypeus and parietale; adnasalia margined with bluntly rounded and truncated teeth ( Fig. 63 ); HL = 0.86–0.90 mm; A/MP = 1.51–1.60; MP/LP = 1.77–1.88; MP2/MP1 = 1.57–1.82; GA/MP1 = 1.67–1.85; LP2/LP1 = 1.28–1.61; MNL/MNW = 2.50–2.72.

Thorax ( Figs 23–24 ): L3 = 1.84–1.92 mm.

Abdomen ( Fig. 22 ): LAS = 0.66–0.72 mm; LAS subconical, not constricted posteriorly at point of insertion of urogomphi. Urogomphus, U = 0.28–0.30 mm, composed of two urogomphomeres; U/HW = 0.28–0.30; U/LAS = 0.42–0.43.

Chaetotaxy: Parietale with 4–6 temporal spines; position and number of secondary setae on legs are shown in Figs 23–24 and Table 7 .

Figures

FIGURE 63. Anterior margin of left adnasalia of selected species of Copelatinae; magnification of 500x except CALT drawn at 400x. Species codes as in Table 1.

FIGURES 21–22. Copelatus japonicus Sharp, 1884, instar III: (21) head capsule, dorsal aspect (scale-like microsculptures not represented); (22) abdominal segment VIII, dorsal aspect. Scale bars = 0.2 mm.

FIGURES 23–24. Copelatus japonicus Sharp, 1884, metathoracic legs, instar III: (23) anterior surface; (24) posterior surface; * = secondary setae (including additional setae, cf. material and methods). Scale bar = 0.2 mm.