Copelatus parallelus Zimmermann, 1920

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 : 177-186

Copelatus parallelus Zimmermann, 1920

Source of material. All larvae studied were reared ex ovo from were adults collected at the following locality: Japan. Kyoto Prefecture. Uji-gawa, Fushimi-ku, Kyoto-shi, Kyoto Prefecture, 34°55’08.8”N 135°45’28.3”E, 6.XI.2016; K. Watanabe leg.

Diagnosis (instar III). The third instar of Copelatus parallelus can easily be distinguished from that of the other species studied in this paper by the following combination of characters: HL = 0.80 mm; L3 <2.00 mm; U = 0.40 mm; head capsule subquadrate, strongly constricted at level of occipital region ( Fig. 48 ), scale-like sculpticels present over frontoclypeus and parietale; anterior margin of frontoclypeus broadly convex, extending mesally at about level of adnasalia ( Fig. 48 ); adnasalia margined with strong acute teeth ( Fig. 64 ); 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 one urogomphomere; U/HW> 0.40; U/LAS> 0.60; Palaearctic.

Description, instar I ( Figs 34–47 )

Body: Measurements and ratios aimed to characterize body shape are shown in Table 2 .

Head ( Figs 34–42 ): HL = 0.43 mm; Head capsule subquadrate, strongly constricted at level of occiput; occipital suture absent; anterior margin of frontoclypeus broadly convex extending beyond level of adnasalia mesally; scale-like sculpticels well-developed over frontoclypeus and parietale; adnasalia margined with strong acute teeth; occipital carina absent; A/MP = 1.27; MP/LP = 2.30; MP2/MP1 = 2.17; GA/MP1 = 2.60; LP2/LP1 = 2.74; MNL/ MNW = 3.66.

Thorax ( Figs 43–44 ): L3 = 0.80 mm.

Abdomen ( Figs 45–47 ): LAS = 0.32 mm; LAS subconical, slightly constricted posteriorly at point of insertion of urogomphi. Urogomphus: U = 0.17 mm, composed of one urogomphomere; U/HW = 0.36; U/LAS = 0.52.

Chaetotaxy ( Figs 34–47 ): Position and number of additional setae on legs are shown in Table 3 and Figs 43–44 .

Description, instar II. As for first-instar larva except as follows:

Body: Measurements and ratios aimed to characterize body shape are shown in Table 4 .

Head: Anterior margin of frontoclypeus extending mesally at about same level of adnasalia; adnasalia margined with strong acute teeth (see Fig. 64 ); occipital suture present; HL = 0.56 mm; A/MP = 1.39; MP/LP = 2.24; MP2/ MP1 = 1.86; GA/MP1 = 2.44; LP2/LP1 = 2.12; MNL/MNW = 3.55.

Thorax: L3 = 1.07 mm.

Abdomen: LAS = 0.41 mm. Urogomphus: U = 0.18 mm, composed of one urogomphomere; U/HW = 0.30; U/LAS = 0.45.

Chaetotaxy: Parietale with 7 temporal spines; position and number of secondary setae on legs are shown in Table 5 .

Description, instar III ( Figs 48–51 , 64 ). As second-instar larva except as follows:

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

Head ( Figs 48 , 64 ): HL = 0.78 mm; A/MP = 1.29; MP/LP = 2.38; MP2/MP1 = 1.69; GA/MP1 = 1.82; LP2/LP1 = 1.67; MNL/MNW = 3.07.

Thorax ( Figs 50–51 ): L3 = 1.47 mm.

Abdomen ( Fig. 49 ): LAS = 0.61 mm; U = 0.40 mm; U/HW = 0.50; U/LAS = 0.65.

Chaetotaxy: Parietale with 7 temporal spines. Position and number of secondary setae on legs are shown in Figs 50–51 and Table 7 .

Figures

FIGURE 64. Anterior margin of left adnasalia of selected species of Copelatinae; magnification of 500x. Species codes as in Table 1.

FIGURES48–49.CopelatusparallelusZimmermann,1920,instar III:(48)headcapsule,dorsalaspect(scale-likemicrosculptures not represented); (49) abdominal segment VIII, dorsal aspect. Scale bars = 0.2 mm.

FIGURES 34–35. Copelatus parallelus Zimmermann, 1920, head capsule, instar I: (34) dorsal aspect; (35) ventral aspect. EB, egg bursters; FR, frontoclypeus; LC, lamellae clypeales; PA, parietale; TP, tentorial pits. Numbers and lowercase letters refer to primary setae and pores, respectively. Scale-like sculptures not represented. Scale bar = 0.1 mm.

FIGURES 36–38. Copelatus parallelus Zimmermann, 1920, head appendages, instar I: (36–37) antenna; (36) dorsal aspect; (37) ventral aspect; (38) mandible, dorsal aspect. AN, antenna; MN, mandible; sp, spinula. Numbers and lowercase letters refer to primary setae and pores, respectively; * = additional sensilla. Scale bars = 0.05 mm.

FIGURES 39–42. Copelatus parallelus Zimmermann, 1920, head appendages, instar I: (39–40) maxilla; (39) dorsal aspect; (40) ventral aspect; (41–42) labium; (41) dorsal aspect; (42) ventral aspect. LA, labium; MX, maxilla. Numbers and lowercase letters refer to primary setae and pores, respectively; * = additional sensilla. Scale bars = 0.05 mm.

FIGURES 43–44. Copelatus parallelus Zimmermann, 1920, metathoracic leg, instar I: (43) anterior surface; (44) posterior surface. CO, coxa; FE, femur; PT, pretarsus; TA, tarsus; TI, tibia; TR, trochanter. Numbers and lowercase letters refer to primary setae and pores, respectively. * = additional sensilla. Scale bar = 0.05 mm.

FIGURES 45–47. Copelatus parallelus Zimmermann, 1920, instar I: (45–46) abdominal segment VIII; (45) dorsal aspect; (46) ventral aspect; (47) urogomphus, dorsal aspect. AB, abdominal segment VIII; UR, urogomphus. Numbers and lowercase letters refer to primary setae and pores, respectively; * = additional sensilla. Spine-like spinulae on abdominal segment VIII not represented. Scale bars = 0.05 mm.

FIGURES 50–51. Copelatus parallelus Zimmermann, 1920, metathoracic legs, instar III: (50) anterior surface; (51) posterior surface; * = secondary setae (including additional setae, cf. material and methods). Scale bar = 0.2 mm.