Exocelina australiae ( Clark, 1863 )

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 : 187

Exocelina australiae ( Clark, 1863)

Source of material. The three instar III larvae studied were collected in association with adults at the following locality: South Australia. Ten kilometers North of Forreston, 9.VIII.1999; C. H. S. Watts leg.

Diagnosis (instar III). The third instar of Exocelina australiae can easily be distinguished from that of the other species studied in this paper by the following combination of characters: HL = 1.85–1.90 mm; L3> 2.90 mm; U> 0.50 mm; head capsule subquadrate, strongly constricted at level of occipital region ( Fig. 54 ), scale-like sculpticels present over frontoclypeus and parietale; anterior margin of frontoclypeus broadly convex, extending mesally at level of adnasalia ( Fig. 54 ); adnasalia margined with mostly short bluntly rounded teeth ( Fig. 65 ); MP2/MP1> 1.50; GA/MP1> 1.50; LP2/LP1> 2.00; inner margin of stipes lacking a dorsal linear row of spinulae; profemur with more than 5 PV and 5 AV secondary setae; metafemur with more than 4 AV secondary setae; urogomphus composed of one urogomphomere; U/HW <0.40; U/LAS <0.50; Australian.

Description, instar III ( Figs 54–55 , 65 )

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

Head ( Figs 54 , 65 ): Head capsule subquadrate, strongly constricted at level of occiput; anterior margin of frontoclypeus broadly convex, extending mesally at about level of adnasalia; scale-like sculpticels present over frontoclypeus and parietale; adnasalia margined with mostly short bluntly rounded teeth ( Fig. 65 ); HL = 1.85–1.90 mm; A/MP = 1.37–1.41; MP/LP = 2.36–2.41; MP2/MP1 = 1.56–1.67; GA/MP1 = 1.53–1.73; LP2/LP1 = 2.00–2.67; MNL/MNW = 2.72–2.96.

Thorax: L3 = 3.71–3.87 mm.

Abdomen ( Fig. 55 ): LAS = 1.33–1.63 mm; LAS subcylindrical, not constricted posteriorly at point of insertion of urogomphi. Urogomphus, U = 0.56–0.58 mm, composed of one urogomphomere; U/HW = 0.25–0.26; U/LAS = 0.35–0.44.

Chaetotaxy: Parietale with 9–10 temporal spines; position and number of secondary setae on legs are shown in Table 7 .

Figures

FIGURE 65. Anterior margin of left adnasalia of selected species of Copelatinae; magnification of 500x, except EAUS and EFER drawn at 400x. Species codes as in Table 1.

FIGURES 54–55. Exocelina australiae (Clark, 1863), instar III: (54) head capsule, dorsal aspect (scale-like microsculptures not represented); (55) abdominal segment VIII, dorsal aspect. Scale bars = 0.2 mm.