Agraphydrus, Komarek & Hebauer, 2018

Komarek, Albrecht & Hebauer, Franz, 2018, Taxonomic revision of Agraphydrus Régimbart, 1903 I. China and Taiwan (Coleoptera: Hydrophilidae: Acidocerinae), Zootaxa 4452 (1), pp. 1-101 : 66-68

Key to the species of Agraphydrus from China and Taiwan

1 Elytra with 9̅10 rows of coarse punctures................................................................. 2

- Elytra with 4̅6 rows of coarse punctures................................................................. 4

2 Antennae with nine antennomeres; coarse punctures on elytra arranged in almost equal rows; pubescence present at least on proximal 2/3 of metafemur (Fig. 87); aedeagus: Fig. 129.............................................. attenuatus

- Antennae with eight antennomeres; coarse punctures on elytra arranged in four primary rows of closely spaced punctures alternating with four to five secondary rows of widely spaced punctures; pubescence present on proximal half of metafemur (Figs. 106, 112); aedeagus: Figs. 148, 154...................................................................... 3

3 Elytral punctures in secondary rows widely spaced (Fig. 28); aedeagus (Fig. 148)........................... insidiator

- Elytral punctures in secondary rows closely spaced (Fig. 34); aedeagus (Fig. 154)............................. politus

4 Six rows of very distinct, coarse punctures present on elytra, mesal series 1 consisting of few punctures near anterior margin; habitus: Fig. 35; aedeagus: Fig. 155............................................................... puzhelongi

- Four rows of distinct or indistinct systematic punctures present on elytra, mesal series 1 present in posterior half, present or absent in anterior half................................................................................. 5

5 Anterior margin of clypeus with angulate excision, median notch present (Fig. 47); aedeagus: apex of median lobe indented, parameres with lateral projections (Figs. 125, 127).......................................................... 6

- Anterior margin of clypeus with evenly rounded excision, median notch absent (Figs. 48‾53, 55‾67); if median notch present (in some individuals of A. fasciatus , Fig. 54), then apex of median lobe not indented, parameres without projections (Fig. 141).................................................................................................... 7

6 Aedeagus (Fig. 127): parameres with distinct subapical bulge on lateral margin............................ anhuianus

- Aedeagus (Fig. 125): parameres without subapical bulge on lateral margin................................... activus

7 Clypeus chagrinate, at least at anterior margin, in some species chagrination restricted to a very narrow seam at anterior margin................................................................................................... 8

- Clypeus entirely lacking chagrination, some species with narrow microsculptured seam at lateral margins or in anterolateral corner, but never at anterior margin...................................................................... 25

8 Maxillary palpomere 4 infuscated apically................................................................ 9

- Maxillary palpomere 4 not infuscated apically............................................................ 11

9 Ground punctures on pronotum and elytra moderate; aedeagus: corona in basal position of median lobe (Fig. 162)................................................................................................ umbrosus (partim)

- Ground punctures on pronotum and elytra very fine or moderate; aedeagus: corona situated in midlength of median lobe (Figs. 126, 164).......................................................................................... 10

10 Ground punctures on pronotum and elytra very fine, interspaces more than 2× as wide as punctures; aedeagus (Fig. 126): lateral margin of parameres straight..................................................................... agilis

- Ground punctures on pronotum and elytra moderate, interspaces 1‾2× as wide as punctures; aedeagus ( Fig. 164 ): lateral mar- gin of parameres curved......................................................................... variabilis

11 Clypeus entirely or almost entirely chagrinated, or chagrination restricted to anterior half........................... 12

- Chagrination of clypeus restricted to a variably extended area on less than anterior half............................ 18

12 Pronotum with weak anterolateral chagrination; aedeagus (Figs. 128, 147): apex of parameres inflated, lateral extension absent................................................................................................... 13

- Pronotum without anterolateral chagrination; aedeagus (Figs. 137, 146, 157, 159, 162): apex of parameres not inflated, lateral extension present or absent........................................................................... 14

13 Elytra dark brown, or light brown with a darker sublateral band widening anteriorly; clypeal and elytral ground punctures fine (Fig. 4); aedeagus: Fig. 128........................................................................ arduus

- Elytra unicolored yellowish or ferruginous; clypeal and elytral ground punctures moderate (Fig. 27); aedeagus: Fig. 147..................................................................................................... igneus 14 Pronotal and elytral ground punctation moderate, body length 2.4‾ 2.8 mm; aedeagus: (Figs. 146, 157)................ 15

- Pronotal and elytral ground punctation very fine to fine, body length 1.8̅ 2.2 mm, rarely larger (some individuals of A. umbrosus may reach 2.5 mm); aedeagus: (Figs. 137, 159, 162)..................................................... 16

15 Elytra slightly attenuating from anterior margin to apex (Fig. 26); aedeagus (Fig. 146): parameres with lateral extension................................................................................................ gracilipalpis

- Elytra parallel-shaped (Fig. 37); aedeagus (Fig. 157): parameres without extension......................... reticuliceps

16 Aedeagus (Fig. 137): parameres distinctly connected with base of median lobe by a distinct band-shaped median extension........................................................................................ connexus (partim)

- Aedeagus (Fig. 159, 162): parameres not visibly connected with base of median lobe............................... 17

17 Aedeagus (Fig. 159): lateral margin of parameres distinctly curving, corona situated in midlength of median lobe.................................................................................................... schoenmanni

- Aedeagus (Fig. 162): lateral margin of parameres weakly curving, corona in basal position of median lobe. umbrosus (partim)

18 Pronotum largely yellow, unicolored or with small mesal infuscation; aedeagus (Fig. 132): median lobe distinctly shorter than parameres, basal lobe very short................................................................ cantonensis

- Pronotum largely dark brown or black, with narrow yellow lateral margins or with decreasing intensity of coloration towards lateral yellow margins; aedeagus: median lobe not shorter than parameres, basal lobe as long as parameres or slightly shorter.................................................................................................... 19

19 Body strongly attenuating towards elytral apex (Figs. 12, 16), eyes very small (Figs. 50, 51)........................ 20

- Body not attenuating towards elytral apex, eyes large or moderately large....................................... 21

20 Aedeagus (Fig. 138): parameres with subapical constriction, apex inflated, corona proximal to midlength of median lobe................................................................................................ contractus

- Aedeagus (Fig. 136): parameres without subapical constriction, apex not inflated, corona distal to midlength of median lobe................................................................................................. conicus

21 Aedeagus (Fig. 145): aedeagus very stout, of almost spherical shape...................................... globipenis

- Aedeagus not very stout, not of spherical shape............................................................ 22

22 Total body length 1.8‾ 2.3 mm; apex of parameres not balloon-shaped (Figs. 137, 143).............................. 23

- Total body length 2.3‾3.0 mm; apex of parameres distinctly balloon-shaped (Figs. 130, 160)......................... 24

23 Aedeagus (Fig. 137): basis of palpomeres connected with basis of median lobe by a distinct band-shaped extension............................................................................................... connexus (partim)

- Aedeagus (Fig. 143): basis of palpomeres not visibly connected with basis of median lobe..................... forcipatus

24 Clypeus, pronotum, and elytra black with narrow yellow lateral margins, ground punctures coarse; habitus cylindrical (Fig. 6); body length 2.6-3.0; aedeagus: Fig. 130............................................................... audax

- Clypeus dark brown, pronotum dark brown with wide yellow lateral margins, elytra brown with darker sublateral band, ground punctures fine; habitus cylindrical or oval (Fig. 40); body length 2.3-2.8; aedeagus: Fig.160..................... setifer

25 Metafemur with reduced pubescence, present on proximal half or restricted to anterior margin (Figs. 89, 98, 108, 114).... 26

- Metafemur pubescent on more than proximal half.......................................................... 29

26 Metafemoral pubescence present on basal half (Figs. 98,114); aedeagus (Figs. 140, 156): phallobase as long as parameres.. 27

- Metafemoral pubescence restricted to anterior margin or absent (Figs. 89, 108); aedeagus (Figs. 131, 150): phallobase shorter than parameres...................................................................................... 28

27 Elytral systematic punctures strongly reduced in number; abdominal ventrite 5 without apical emargination; body length 1.5‾ 1.7 mm; aedeagus: Fig. 156................................................................... reductus

- Elytral systematic punctures very coarse, numerous; abdominal ventrite 5 with shallow apical emargination; body length 2.1‾ 2.5 mm; aedeagus: Fig. 140.................................................................. decipiens

28 Antennae nine-segmented; body length 2.2‾3.0 mm; eyes large; abdominal ventrite 5 with apical emargination; aedeagus (Fig. 150): parameres less than 2× as long as basal lobe, corona in basal position, crescentic sclerotized structure present.................................................................................................... longipalpus

- Antennae eight-segmented; body length 1.8 mm; eyes small; abdominal ventrite 5 without apical emargination; aedeagus (Fig. 131): parameres more than 2× as long as basal lobe, corona located distal to midlength of median lobe, shield-shaped sclerotized structure present.............................................................................. calvus

29 Maxillary palpomere 4 apically infuscated; elytra widening posterior of midlength (Figs. 10, 11, 17, 18, 19, 29, 38)....... 30

- Maxillary palpomere 4 apically not infuscated; elytra not widening posteriorly (Figs. 9, 21, 22, 24, 31, 32, 33, 41, 43, 45, 4 6).................................................................................................... 34

30 Elytra dark brown or black (Fig. 29); aedeagus: Fig. 149............................................... jilanzhui

- Elytra light brown or yellow (Figs. 10, 11, 17, 18, 19, 38); aedeagus: Figs. 134, 135, 139, 158....................... 31

31 Aedeagus (Fig. 158): apex of parameres with lateral extensions........................................... robustus

- Aedeagus (Fig. 134, 135, 139): apex of parameres without extensions.......................................... 32

32 Aedeagus (Fig. 135): apex of parameres strongly bending mesad........................................ confusus

- Aedeagus (Figs. 134, 139): apex of parameres not strongly bending mesad...................................... 33

33 Aedeagus (Fig. 134): apex of parameres attenuating apicad............................................... comes

- Aedeagus (Fig. 139): apex of parameres not attenuating apicad.......................................... coomani

34 Body length> 3.0 mm, width> 1.5 mm; clypeus yellow, with or without small central infuscation; eyes slightly protruding (Fig. 43); aedeagus: Fig. 163..................................................................... uncinatus

- Body length <3.0 mm, width <1.5 mm; clypeus dark brown or black with or without yellow preocular patches; eyes not pro- truding............................................................................................ 35 35 Antennae with eight antennomeres..................................................................... 36

- Antennae with nine antennomeres...................................................................... 42

36 Abdominal ventrite 5 truncate, apical emargination absent................................................... 37

- Abdominal ventrite 5 with apical emargination............................................................ 39

37 Body length 2.0 mm; habitus broad (E.I.: 1.3; Figs. 21, 24); eyes small, lateral margin of clypeus 2.5̅2.6× as long as lateral margin of eyes; length ratio palpomeres 4:3 = 1.1‾1.2 (Figs. 72, 73); mesoventrite carinate; metafemoral pubescence present on proximal 2/3̅3/4................................................................................. 38

- Body length 1.7 mm; habitus slender (E.I.: 1.5; Fig. 45 ); eyes large, lateral margin of clypeus 1.5× as long as lateral margin of eyes; length ratio palpomeres 4:3 = 1.5 (Fig. 81); mesoventrite without carina; metafemoral pubescence present on proximal 4/ 5; aedeagus: Fig. 165 .......................................................................... wangmiaoi

38 Maxillary palpi as long as pronotum, slightly shorter than clypeal width; aedeagus: Fig. 144.................. fujianensis

- Maxillary palpi 1.2× as long as pronotum, as long as clypeal width; aedeagus: Fig. 141................. fasciatus (partim)

39 Eyes small, lateral margin of clypeus 2.4‾2.6× as long as lateral margin of eyes; clypeus 3.8‾3.9× as wide as long; length ratio maxillary palpomere 4:3 = 1.1; mesoventrite with low median carina............................................ 40

- Eyes moderate to large, lateral margin of clypeus 1.9× as long as lateral margin of eyes; clypeus 4.8‾5.3× as wide as long; length ratio maxillary palpomere 4:3 = 1.3; mesoventrite without carina......................................... 41

40 Clypeus with yellow preocular patches; pronotum and elytra brown (Fig. 21); aedeagus: Fig. 141........ fasciatus (partim)

- Clypeus without preocular patches; pronotum and elytra black (Fig. 33); aedeagus: Fig. 153....................... niger

41 Aedeagus ( Fig. 166 ): median lobe moderately wide................................................ yunnanensis

- Aedeagus (Fig. 151): median lobe very narrow...................................................... longipenis

42 Clypeus and pronotum dark yellow mesally, elytral systematic punctures very coarse, mesal row 1 reaching anterior margin, an additional series of coarse punctures present along lateral margin in most individuals; aedeagus: Fig. 142........... fikaceki

- Clypeus and pronotum dark brown or black mesally; elytral systematic punctures indistinct or moderately distinct, mesal row 1 not reaching anterior margin, additional lateral series absent................................................... 43

43 Eyes large, lateral margin of clypeus 1.7‾1.8× as long as lateral margin of eyes; mesoventrite with mesal bulge; abdominal emargination present................................................................................. 44

- Eyes small, lateral margin of clypeus 3.2× as long as lateral margin of eyes; mesoventrite with low crescentic horizontal ridge; abdominal emargination absent; aedeagus: Fig. 133.................................................... chinensis

44 Ground punctures on pronotum and elytra fine; maxillary palpi 1.1× as long as pronotum; length ratio palpomeres 4:3 = 1.4 (Fig. 80); aedeagus (Fig. 161): apex of parameres flat without projections.................................. splendens

- Ground punctures on pronotum and elytra moderate; maxillary palpi 0.8× as long as pronotum; length ratio palpomeres 4:3 = 1.1 (Fig. 77); aedeagus (Fig. 152): apex of parameres with two lateral projections........................... masatakai

Figures

FIGURES 164–166. Aedeagus: 164) A. variabilis; 165) A. wangmiaoi; 166) A. yunnanensis. Scale = 0.1 mm.

FIGURES 45–46. Habitus: 45) A. wangmiaoi; 46) A. yunnanensis. Scale = 1 mm.