Parhydraena

Perkins, Philip D., 2009, Revisions of the genera Parhydraena Orchymont, Protozantaena Perkins, Decarthrocerus Orchymont, and Parhydraenopsis nomen novum, aquatic and humicolous beetles from Africa and Madagascar, and comparative morphology of the tribe Parhydraenini (Coleoptera: Hydraenidae), Zootaxa 2038, pp. 1-119 : 12-13

Key to species of Parhydraena

1 Wide, broad-shouldered species with very short maxillary palpi and short tarsi (e.g., Figs. 2, 63, 64), maxillary palpus length/head width ratio ca. 0.44–0.57, metatibia + metatarsus length/head width ratio ca. 1.09–1.14; humicolous or subhumicolous ( toro group) ................................................................................................................ 2

- More elongate species with longer maxillary palpi and longer legs (e.g., Figs. 2, 38, 47), maxillary palpus length/ head width ratio ca. 0.54–0.91, metatibia + metatarsus length/head width ratio ca. 1.27–1.53; aquatic .................... 5

2 Elytral series and intervals each with unilinear row of large granules; punctures on pronotal relief coarse, U-shaped; frons disc tumid; aedeagus as illustrated ( Figs. 64, 66) ................................................................................. toro n. sp.

- Elytra non-granulate or granules minute and very indistinct; punctures on pronotal disc finer, sparser; frons disc not tumid ............................................................................................................................................................................ 3

3 Tarsi and maxillary palpi shorter, palpus length/head width ratio ca. 0.44; pronotal disc more convex, anterior impression more distinctly V-shaped, extending to middle of pronotum; aedeagus as illustrated ( Figs. 63, 65) .......... .................................................................................................................................................................. brahma n. sp.

- Tarsi and maxillary palpi slightly longer, palpus length/head width ratio ca. 0.57; pronotal disc less convex ............ 4

4 Pronotal relief less finely punctate, many punctures distinctly U-shaped or divided into two smaller punctures; size smaller, ca. 1.78 mm; aedeagus as illustrated ( Figs. 59, 61) ............................................................. brunovacca n. sp.

- Pronotal relief very finely and sparsely punctate; size larger, ca. 1.97 mm; aedeagus as illustrated ( Figs. 60, 62) ...... ......................................................................................................................................................... mpumalanga n. sp.

5 Maxillary palpi comparatively short, palpus length/head width ratio ca. 0.54–0.70 ................................................... 6

- Maxillary palpi longer, palpus length/head width ratio ca. 0.75–0.91........................................................................ 10

6 Elytra semicostate; aedeagus as illustrated ( Figs. 55, 57)................................................................. semicostata n. sp.

- Elytra not semicostate .................................................................................................................................................. 7

7 Elytral series 3–8 with punctures more-or-less random; pronotal relief very finely and very sparsely punctate, lateral areas rugose; maxillary palpi comparatively short, palpus length/head width ratio ca. 0.64; comparatively large species, length ca. 2.17 mm; aedeagus as illustrated ( Figs. 58, 76) .................................................... sebastiani n. sp.

- Elytral punctures serial; pronotal relief punctation coarser; smaller species, length less than 2.17 mm ..................... 8

8 Frons and pronotal relief very coarsely, densely punctate; labrum large, as long as clypeus, in male anterior margin reflexed; male 5th ventrite simple; larger species, ca. 1.98 mm; Sudan; aedeagus as illustrated ( Figs. 35, 37) ........... ..................................................................................................................................................................... divisa n. sp.

- Frons and pronotal relief less coarsely punctate; labrum shorter than clypeus; smaller species, ca. 1.75–1.83 mm .... ...................................................................................................................................................................................... 9

9 Smaller species, ca. 1.76 mm, body form broader; maxillary palpi shorter, palpus length/head width ratio ca. 0.54; male 5th ventrite with semicircular saucer-like modification; South Africa; aedeagus as illustrated ( Fig. 50, 52) ....... ............................................................................................................................. lancicula Perkins & Balfour-Browne

- Larger species, ca. 1.83 mm, body form narrower; maxillary palpi longer, palpus length/head width ratio ca. 0.88; male 5th ventrite simple; Kenya; aedeagus as illustrated ( Fig. 34, 36) .................................. brevipalpis (Régimbart)

10 Elytral serial punctures obsolete, unilinear row of granules of series and intervals large, closely spaced; comparatively large species, length ca. 1.93 mm; aedeagus as illustrated ( Figs. 2, 47, 49) .................. asperita n. sp.

- Elytral serial punctures discrete, granules of series and intervals minute, if perceptible, more widely spaced; body size variable ................................................................................................................................................................ 11

11 Pronotum with large, dark brown, abruptly margined macula surrounded by testaceous color; maxillary palpi comparatively long, palpus length/head width ratio ca. 0.91; aedeagus as illustrated ( Figs. 39, 41) ............................. .......................................................................................................................................................... maculicollis n. sp.

- Pronotum non-maculate, unicolorous dark, or with disc darker than, and gradually transitioning to, lighter lateral color; maxillary palpi shorter, compared to head width ............................................................................................ 12

12 Eyes comparatively coarsely faceted, in dorsal aspect ca. 7 facets in longest series; frons markedly microreticulate, dull ............................................................................................................................................................................. 13

- Eyes generally larger, with smaller facets, ca. 9 or 10 in longest series; frons at most effacedly microreticulate, weakly shining ........................................................................................................................................................... 15

13 Body size smaller, length ca. 1.64 mm; maxillary palpi comparatively longer, palpus length/head width ratio ca. 0.90; aedeagus as illustrated ( Figs. 42, 44) ................................................................................................ parva n. sp.

- Larger species, length ca. 1.75 mm; maxillary palpi comparatively shorter, palpus length/head width ratio ca. 0.75–0.78 .................................................................................................................................................................... 14

14 Abdominal ventrite 6 in males with prominent tubercle in midline, area posterior. to tubercle markedly concave; aedeagus as illustrated ( Figs. 54, 56) ............................................................................................................ ora n. sp.

- Abdominal ventrite 6 in males with low transverse ridge over median 1/3; aedeagus as illustrated ( Figs. 51, 53)....... ................................................................................................................................................................ namaqua n. sp.

15 Larger species, length ca. 2.00 mm; elytral intervals wider, ca. 2–3xpd; legs comparatively longer, metatibia + metatarsus length/head width ratio ca. 1.43; pronotal relief more finely punctate; aedeagus as illustrated ( Figs. 38, 40) ...................................................................................................................................................... maureenae n. sp.

- Smaller species, length ca. 1.75 mm; elytral intervals narrower, ca. 1–2xpd; legs comparatively shorter, metatibia + metatarsus length/head width ratio ca. 1.33; pronotal relief punctation coarser ........................................................ 16

16 Abdominal ventrite 6 in male with middle part glabrous and swollen in anterior 2/3, posterior 1/3 depressed and sparsely setose, two minute papillae, side-by-side, in midline at juncture of swollen and depressed areas; aedeagus as illustrated ( Figs. 46, 48) ............................................................................................................................ ancylis n. sp.

- Abdominal ventrite 6 in male with anterior part gradually swollen, middle shallowly impressed; aedeagus as illustrated ( Figs. 43, 45) ........................................................................................................... seriata Balfour-Browne