Ochthebius

Perkins, Philip D., 2011, New species and new collection records of aquatic beetles in the genus Ochthebius Leach from southern Africa (Coleoptera: Hydraenidae), Zootaxa 3093, pp. 1-34 : 3-4

Key to subgenera, groups and species of southern African Ochthebius

1 Pronotum with sides of sclerotized part gradually rounded from anterior angles to beyond middle, then produced as minute point in front of excavate posterior angles; pronotal disc with distinct midlongitudinal sulcus, but lacking anterior and posterior foveae.............................................................................. Asiobates Stephens 2

- Pronotum with sides of sclerotized part sinuately attenuate or gradually arcuate to basal angles; pronotal impressions various, but never with combination as stated above................................................... Ochthebius (s.s.) 3

2 Body more robust; size larger, ca. 2.12 mm; pronotum very coarsely, deeply and densely punctate; elytra deeply striateimpressed ( Fig. 15 ).......................................................................... O. bupunctus

- Body less convex, less robust; size smaller, ca. 1.98 mm; pronotum less densely punctate; elytra weakly or not striateimpressed.................................................................................. O. andronius

3 Head with frontoclypeal suture very weakly impressed; labrum subequal in length to clypeus, slightly inclined if at all; intercoxal ventrite and anterior part of 1st abdominal ventrite withdrawn under metaventrite, pubescent part of 1st ventrite forming part of coxal cavity; legs elongate, metafemora slender; inhabits rock pools in coastal splash zone......... Capicola group 4

- Head with frontoclypeal suture deeply impressed; labrum shorter than and inclined at distinct angle to clypeus; intercoxal ventrite visible; metacoxal cavities distinctly rimmed posteriorly................................................... 5

4 Elytral punctures serial except random near suture basally, near humerus, and laterally beyond 8th series; pronotum with lateral lobes rugulose, discal interstices shining; large species (ca. 2.40 mm).................................... O. rubripes

- Elytral punctures completely random; pronotum uniformly finely microreticulate, dull; smaller species (ca. 1.92 mm)................................................................................................... O. capicola

5 Dorsum black with distinctive white pubescence; pronotum with midlongitudinal sulcus; metaventrite uniformly clothed with very dense and very short hydrofuge pubescence............................................. Namibiensis group 6

- Dorsum at least in part brownish or testaceous; pronotum with or without midlongitudinal sulcus; metaventrite posteromedially with setae less dense than and cuticle more shining than lateral area, sometimes strongly shining and nearly glabrous.. 9

6 Elytron without "accessory series" between 1st and 2nd series and between 9th and 10th series; explanate margin of elytron distinctly wider in front of than behind middle (in female about as wide as mesotibia); pronotal posterior foveae well-developed, microreticulate within............................................................................. 7

- Elytron with "accessory series" between 1st and 2nd series (in basal 1/3) and another between 9th and 10th series (punctures sometimes subserially arranged); explanate margin of elytron very narrow in both sexes, widest at midlength; pronotal posterior foveae varying from obsolete to well-developed.......................................................... 8

7 Size larger (ca. 1.87 mm); sides of elytra more rounded; pronotal anterior foveae more widely separated from posterior foveae, together circumscribing an elongate rectangle.................................................... O. namibiensis

- Size smaller (ca. 1.71 mm); sides of elytra less rounded; pronotal anterior foveae less widely separated from posterior foveae, together circumscribing a square ( Fig. 11 )............................................................. O. zulu

8 Pronotal sides concavely attenuate from near anterior angles, hyaline border very wide, nearly as wide as subdigitiform, sharply rounded lateral lobe; pronotal posterior foveae well-developed................................... O. spatulus

- Pronotal sides sinuately attenuate, concave from about middle to posterior angles, hyaline border much narrower than widely rounded lateral lobe; pronotal posterior foveae obsolete or weakly developed........................... O. pagotrichus

9 Elytral intervals 2, 3, 5, and 7 each with unilinear row of erect short fine setae; labrum in both sexes bearing non-spiniform setae, anterior margin apicomedially emarginate; pronotal foveae confluent medially with shallow midlongitudinal impression (location marked by microreticulation); ( Extremus group)............................................ O. extremus

- Elytral intervals without rows of erect setae; labrum various; pronotal impression various........................... 10

10 Elytral punctures random; body form compressed; pronotal impressions very shallow; male labrum not strongly upturned, without spiniform setae; flightless species; Involatus group ( Fig. 13 )................................... O. involatus

- Elytral punctures serial; labrum in male with anterior margin apicomedially reflexed, usually with short spiniform setae forming group on each side of middle,; pronotal impression various.................................. Salinarius group 11

11 Pronotum with midlongitudinal sulcus well-developed, even in middle; anterior and posterior foveae separate from or only very shallowly joined to sulcus; elytron testaceous with partial or complete brownish longitudinal lines through each series 12

- Pronotum with midlongitudinal impression restricted to anterior and posterior, obsolete if at all present over median area; anterior and posterior foveae deeply confluent with respective parts of midlongitudinal impression; elytron without longitudinal lines of color, often with darker coloration at summit of posterior declivity....................................... 13

12 Elytra with complete, well formed longitudinal lines of color through each series......................... O. salinarius

- Each elytral puncture with a dark brown dot, some of which are contiguous, but not forming parallel-side dark lines ( Fig. 1 )............................................................................................ O. endroedyi

13 Pronotal reliefs finely sparsely punctate; metaventrite with small basomedian area less densely pubescent and more shining than remainder, which is microreticulate beneath hydrofuge pubescence; female with narrow median glabrous weakly shining area on ventrites 2–4 and anterior part of 5; size larger (ca. 1.85–2.10 mm)................................. O. pedalis

- Pronotal reliefs with coarse, irregularly spaced punctures, some confluent; metaventrite pubescent laterally, disc strongly shining, glabrous except few setiferous punctures; smaller species (ca. 1.60–1.80 mm)................................. 14

14 Color generally dark brown, elytra uniformly colored, without darker dot around each serial puncture; elytra with a granule at the anterior margin of each serial puncture ( Fig. 7 )................................................. O. granulinus

- Elytra lighter brown, with darker color around each serial puncture, caused by the underlying columellae; elytra without granules............................................................................................... 15

15 Pronotal posterior foveae deeper laterally than medially; females with hydrofuge pubescence very sparse in midline of ventrites 3–5........................................................................................... 16

- Pronotal posterior foveae markedly confluent, deeper medially than laterally; females with hydrofuge pubescence not significantly sparser in midline of ventrites 3–5.................................................................. 17

16 Pronotal posterior foveae deeper and with more abrupt lateral margins; body less convex; elytra with less rounded sides and less acuminate apices; size larger (ca. 1.74 mm); aedeagus as illustrated ( Figs. 5 , 6)........................ O. anchorus

- Pronotal posterior foveae shallower and with less abrupt lateral margins; body more convex; elytra with more rounded sides and more acuminate apices; size smaller (ca. 1.66 mm);............................................... O. spinasus

17 Metaventral glabrous area triangular; size larger (ca. 1.77 mm); aedeagus as illustrated ( Figs. 3 , 4)............. O. sitiensis

- Metaventral glabrous area subrhomboidal; size smaller (ca. 1.67 mm); aedeagus as illustrated ( Figs. 9 , 10)..... O. bicomicus

Figures

FIGURE 1. Ochthebius endroedyi, dorsal and lateral habitus of holotype.

FIGURE 3. Ochthebius sitiensis, dorsal and lateral habitus of holotype.

FIGURE 5. Ochthebius anchorus, dorsal and lateral habitus of holotype.

FIGURE 7. Ochthebius granulinus, dorsal and lateral habitus of holotype.

FIGURE 9. Ochthebius bicomicus, dorsal and lateral habitus of holotype.

FIGURE 11. Ochthebius zulu, dorsal and lateral habitus of holotype.

FIGURE 13. Ochthebius involatus, dorsal and lateral habitus of holotype.

FIGURE 15. Ochthebius bupunctus, dorsal and lateral habitus of holotype.