Sandracottus Sharp, 1882

Alarie, Yves, Michat, Mariano C., Shaverdo, Helena & Hájek, Jiří, 2023, Morphology of the larvae of Sandracottus femoralis Heller, 1934, and S. mixtus (Blanchard, 1843) and phylogenetic comparison with other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae), Zootaxa 5263 (3), pp. 301-334 : 303

Larvae of Sandracottus Sharp, 1882

( Figs 1–29 , 31–36 )

Diagnosis. Larvae of Sandracottus can readily be distinguished from those of other genera of Aciliini described in detail by the following combination of characters: presence of at least 20 additional spiniform setae on dorsal surface of stipes (instar I) ( Fig. 6 ), median process of prementum elongate, about as long as labial palpomere 1 ( Figs 8–9 , 19 , 34 ) (instar I–III), presence of more than 23 anteroventral additional setae on femur ( Fig. 10 ) (instar I).

Figures

FIGURES 1–2. Sandracottus femoralis Heller, 1934, head capsule, instar I: (1) dorsal aspect; (2) ventral aspect. EB, egg bursters; FR, frontoclypeus; LC, lamellae clypeales; PA, parietal; TP, tentorial pits. Numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.5 mm.

FIGURES 3–5. Sandracottus femoralis Heller, 1934, head appendages, instar I: (3–4) antenna; (3) dorsal aspect; (4) ventral aspect; (5) mandible, dorsal aspect. AN, antenna; MN, mandible; sp, spinula. Numbers and lowercase letters refer to primary setae and pores, respectively. Scale bars = 0.1 mm.

FIGURES 6–9. Sandracottus femoralis Heller, 1934, head appendages, instar I: (6–7) maxilla; (6) dorsal aspect; (7) ventral aspect; (8–9) labium; (8) dorsal aspect; (9) ventral aspect. LA, labium; MX, maxilla. Numbers and lowercase letters refer to primary setae and pores, respectively; * = additional sensilla. Scale bars = 0.1 mm.

FIGURES 10–11. Sandracottus femoralis Heller, 1934, mesothoracic leg, instar I: (10) anterior surface; (11) 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 = 0.2 mm.

FIGURES 12–14. Sandracottus femoralis Heller,1934, instar I: (12–13) abdominal segment VIII; (12) dorsal aspect;(13) ventral aspect; (14) urogomphus, dorsal aspect. AB, abdominal segment VIII; UR, urogomphus. Numbers and lowercase letters refer to primary setae and pores, respectively. Spine-like spinulae on abdominal segment VIII not represented. Scale bars = 0.2 mm.

FIGURES 15–19. Sandracottus femoralis Heller, 1934, instar II: (15) parietale, ventral aspect; (16) antennomere I, dorsal aspect; (17) mandible, ventral aspect; (18) maxilla, dorsal aspect; (19) prementum, ventral aspect. Scale bars = 0.5 mm (Fig. 15), 0.1 mm (Figs 16–19).

FIGURES 20–21. Sandracottus femoralis Heller, 1934, instar II, mesothoracic leg: (20) anterior surface; (21) posterior surface. Scale bar = 0.2 mm.

FIGURES 22–24. Sandracottus femoralis Heller, 1934, instar III: (22) lateral habitus; (23) head capsule. dorsal aspect; (24) abdominal segments VII–VIII, dorsal aspect. Photos by Y. Alarie.

FIGURES 25–29. Sandracottus femoralis Heller, 1934, instar III: (25) parietal, ventral aspect; (26) antenna, dorsal aspect; (27) maxilla, dorsal aspect; (28–29) mesocoxa and mesotrochanter: (28) anterior surface; (29) posterior surface. Scale bars = 0.5 mm (25) and 0.2 mm (26–29).

FIGURES 31–32. Sandracottus mixtus (Blanchard, 1843), lateral habitus: (31) instar I; (32) instar II. Photo by H. Schillhammer.

FIGURES 33–34. Sandracottus mixtus (Blanchard, 1843), instar I: (33) antenna, dorsal aspect; (34) labium, dorsal aspect.AN, antenna; LB, labium. Numbers and lowercase letters refer to primary setae and pores, respectively. Scale bars = 0.1 mm.

FIGURES 35–36. Sandracottus mixtus (Blanchard, 1843), instar III: (35) dorsal habitus; (36) lateral habitus. Photo by H. Schillhammer.