Neochthebius d’Orchymont, 1932

Park, Sun-Jae & Ahn, Kee-Jeong, 2008, Redescription of the littoral genus and species of Neochthebius granulosus (Satô), and the first larval description for the genus (Coleoptera: Hydraenidae: Ochthebiinae), Journal of Natural History 42 (39 - 40), pp. 2501-2514 : 2502-2505

Genus Neochthebius d’Orchymont

Neochthebius d’Orchymont, 1932: 43 ; Perkins, 1980: 408; Hansen, 1991: 42.

Type species: Ochthebius vandykei Knisch, 1924 .

See Perkins (1980) for other synonymy and references.

Description

Length about 1.4–1.6 mm. Body ( Figures 1–2 ) almost unicolour, dark brown to dull black; elongate, narrow, convex; dorsum covered with some distinct white setae. Head ( Figures 15–16 ) widest across eyes; two distinct punctures present between eyes; strongly microreticulate and granular. Clypeus ( Figures 15–16 ) with finely impressed clypeal line; apical margin truncate; strongly microreticulate and granular. Eyes small; facets relatively large. Antennae ( Figure 3 ) with nine Figures 9–14. (9–11) antennomere 2; (12–14) maxillary palpomere 3. (9–10 and 12–13) Neochthebius granulosus ; (11 and 14) N. vandykei .

antennomeres; apical five antennomeres clubbed and pubescent; scape longest, clearly imbricate; pedicel strongly bulbed basally, narrowed apically, weakly or clearly imbricate (Figures 9–11); antennomere 3 small, somewhat bulbed apically; 4 crescent shape; and 5–9 compact. Labrum ( Figure 4 ) transverse, moderately large, rounded; apical margin weakly serrate, slightly emarginate medially; strongly microreticulate. Mandibles ( Figure 5 ) almost symmetrical, triangular; apex acute, with roughly serrated large retinaculum; mola with grinding region; lateral margin with one long seta and some short setae; hidden under labrum. Maxillary palpomere 3 longest, thick, weakly or clearly imbricate (Figures 12–14); and 4 small, slender, apex with some extremely short setae. Galea ( Figure 6 ) slender; apex with some long and short setae. Lacinia with some large spines and long setae along inner margin; apex acute. Labial palpi very slender, indistinct. Mentum hexagonal; narrowed basally; apical margin broadly emarginate; some long flexible setae present on each antero-lateral region; somewhat microreticulate. Pronotum ( Figures 19–21 ) about as wide as or slightly wider than long; widest in front of middle; moderately narrowed apically, strongly narrowed basally; three distinct or indistinct longitudinal impressions and fine lateral impression present; strongly microreticulate and granular. Elytra ( Figures 1–2 and 19–21 ) longer than wide; 10 indistinct rows of punctures present, each with a distinct white seta; surface uneven. Hind wings absent. Scutellum small, transverse, pentagonal (visible as triangular); most hidden under pronotum; basal margin broadly emarginate; strongly imbricate. Prosternum ( Figures 22–23 ) weakly convex; procoxae almost contiguous; procoxal cavities open; strongly imbricate. Mesoventrite ( Figures 22–23 ) not carinate; mesocoxae narrowly separated; apex of mesocoxal process acute and reached to metacoxal process, isthmus absent; strongly imbricate. Metaventrite ( Figures 24–25 ) relatively short; metacoxae almost contiguous; strongly imbricate. Legs slender. Femur normal, transverse; clearly imbricate; profemur with a series of fine setae dorsally. Tibia slender, some fine sparse spines present, microreticulate; metatibia slightly outcurved. Tarsal formula 5–5–5, tarsomeres 1–4 small; and 5 long, as long as 1–4 combined. Abdomen ( Figures 24–25 ) strongly imbricate; last abdominal segment of female with a row of some large spines apically ( Figures 17–18 ). Aedeagus slender; apex with a large distal lobe on left side in dorsal aspect, distal lobe sinuate; with some relatively long setae near apex ventrally in lateral aspect; moderately curved in lateral aspect. Parameres thin; moderately expanded at apex; apex with very short setae ventrally.

Key to the species of the genus Neochthebius

1. Mesoventrite as in Figure 23 , mesoventral process blunt apically; metaventrite and abdominal sternites relatively weakly setose ( Figure 25 ); elytra weakly uneven ( Figure 21 ).......... Neochthebius vandykei (Knisch)

– Mesoventrite as in Figure 22 , mesoventral process sharply pointed apically; metaventrite and abdominal sternites strongly setose ( Figure 24 ); elytra strongly uneven ( Figures 19–20 )..................................................... N. granulosus (Satô)

Figures

Figures 1–2. SEM habitus photos. (1) Neochthebius granulosus; (2) N. vandykei.

Figures 15–18. (15–16) head; (17–18) female last abdominal segment, ventral aspect. (15 and 17–18) Neochthebius granulosus; (16) N. vandykei.

Figures 3–8. Neochthebius granulosus. (3) antenna, dorsal aspect; (4) labrum, dorsal aspect; (5) mandible, dorsal aspect; (6) maxilla, ventral aspect; (7) aedeagus, dorsal aspect; (8) aedeagus, lateral aspect. Note: Scales50.1 mm.

Figures 19–21. Pronotum and elytra. (19–20) Neochthebius granulosus; (21) N. vandykei.

Figures 22–25. (22–23) pro- and mesoventrite; (24–25) metaventrite and abdomen. (22 and 24) Neochthebius granulosus; (23 and 25) N. vandykei.