Hydraena
Creators: name: Freitag, Hendrik
name: Jäch, Manfred A.
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydraenidae
Hydraena

description: Key to the known species of Hydraena from Palawan and Busuanga
1 Total length usually> 1.3 mm ................................................................................................................... 2
- Total length usually <1.3 mm ................................................................................................................... 9
2 Entire body and pronotum about twice as wide as long; general habitus rather robust; elytra and pronotum distinctly punctate, punctures deeply impressed (Fig. 13). Male: aedeagus with long apical flagellum (Fig. 27 a). Female: gonocoxite subcrescentic, setae of subapical tufts furcate (Fig. 27 e) .................................... .............................................................................................................. H. busuanga Freitag & Jäch, sp. n.
- Pronotum wider than long, but never twice as wide as long (Figs. 3, 6–9, 11, 12) ................................... 3
3 Pronotal disc with distinct dark, rectangular or irregular spot (Figs. 3, 7, 8, 11, 12) ................................ 4
- Pronotum evenly reddish or golden brown, without distinct dark rectangular spot (Figs. 6, 9) ............... 8
4 Lateral elytral gutter distinctly explanate (Figs. 7, 8), pseudepipleuron broad, reaching beyond posterior 0.2 .............................................................................................................................................................. 5
- Lateral elytral gutter only slightly explanate anteriorly, pseudepipleuron not reaching posterior 0.2 (Figs. 3, 11, 12) .................................................................................................................................................... 6
5 Male: aedeagus about half as broad as long, ejaculatory duct ending in a strongly (more than 90°) curved, flagellum-like structure (Fig. 20 a) ........................................................... H. claudia Freitag & Jäch, sp. n.
- Male: aedeagus about one third as broad as long, ejaculatory duct ending in an obtusely (less than 45°) bent tube-like structure (Fig. 19 a) .................................................. H. castanescens Freitag & Jäch, sp. n.
6 Elytral punctures small and only moderately impressed (Fig. 12). Male: inner side of hind tibia unilaterally dilated (Fig. 12); parameres inserted at basal 0.2 of aedeagus, longer than median lobe (Fig. 26 b). Female: gonocoxite crescentic, with two distinctly separated cavities, short apical tufts of setae not distinctly longer than setae on disc (Fig. 26 e) ............................................ H. hosiwergi Freitag & Jäch, sp. n.
- Elytral punctures large and distinctly impressed (Fig. 3, 11). Male hind tibia not unilaterally dilated (Figs. 3, 11); gonocoxite and aedeagus different (Figs. 15 a–c, e; 25a–c, e) ........................................................ 7
7 Male: aedeagus Y-shaped, with medioapical gap (Fig. 25 a). Female: gonocoxite subcrescentic to subrectangular, condyles inconspicuous (Fig. 25 e) .......................................... H. manguao Freitag & Jäch, sp. n.
- Male: aedeagus compact and intricately shaped (Fig. 15 a). Female: gonocoxite subtrapezoidal, condyles prominent (Fig. 15 e) .................................................................................... H. scabra d’Orchymont, 1925
8 Elytron with> 13 rows of punctures (Fig. 6). Male: distal lobe of aedeagus distinctly asymmetric, tapered and hood-like; parameres short and stout (Fig. 18 a). Female: disc of tergite X with squamose setae, with an apical notch (Fig. 18 h) .......................................................................... H. zetteli Freitag & Jäch, sp. n.
- Elytron with <13 rows of punctures (Fig. 9). Male: distal lobe of aedeagus broad, subsymmetric; parameres long and slender (Fig. 21 a). Female: disc of tergite X with trichoid setae, without apical notch (Fig. 21 h) ................................................................................................ H. kodadai Freitag & Jäch, sp. n.
9 Pronotum distinctly sinuously or arcuately convergent posteriorly; posterior margin only 0.75–0.80 times as broad as pronotal width across middle, dark rectangular spot usually indistinct or lacking (Figs. 4–6, 9) .................................................................................................................................................................. 10
- Pronotum only slightly and evenly convergent posteriorly; posterior margin more than 0.80 times as broad as pronotal width across middle, dark rectangular spot distinct (Figs. 10, 11) ....................................... 12
10 Total length ca. 1.3 mm. Lateral elytral gutter widely explanate, rather straight and subparallel at anterior 0.2–0.7; body usually reddish to golden brown (Figs. 6, 9). Male: aedeagal parameres either asymmetric, stout, with tufts of fused setae (Fig. 18 a) or subsymmetric and elongate (Fig. 21 a). Female: tergite X either with squamose setae on disc (Fig. 18 h) or without apical notch (Fig. 21 h) .................................... 8
- Total length <1.3 mm. Elytra rather ovoid, lateral margins moderately explanate; usually greyish to yellowish brown (Figs. 4, 5). Male: aedeagal parameres always asymmetrical, stout, without fused tufts of setae, but with separate setae. Female: tergite X with one apical notch, without squamose setae on disc
(Figs. 16 h, 17h) ........................................................................................................................................ 11 11 Total length> 1.2 mm. Male: distal lobe of aedeagus ovoidly rounded (Fig. 16 b). Female: subapical fringe of tergite X with vermiform setae (Fig. 16 h) .................................... H. jojoorculloi Freitag & Jäch, sp. n.
- Total length <1.2 mm. Male: distal lobe of aedeagus not ovoid, with few short appendages (Fig. 17 a). Female: tergite X without vermiform setae (Fig. 17 h) ..................... H. nielshaggei Freitag & Jäch, sp. n.
12 Mesoventral intercoxal process narrower than pseudepipleuron, not reaching posterior margin of mesocoxa, not firmly connected with metaventrite. Male: aedeagus Y-shaped, with medioapical gap (Fig. 25 a). Female: gonocoxite subcrescentic to subrectangular (Fig. 25 e); tergite X with only one apical notch, subapical fringe with vermiform setae (Fig. 25 h) ...................................... H. manguao Freitag & Jäch, sp. n.
- Mesoventral intercoxal process very wide and long, broader than pseudepipleuron, reaching beyond posterior margin of mesocoxa, firmly connected with metaventrite. Male: aedeagus compact and intricately shaped (Figs. 22 a–c, 23a–c). Female: gonocoxite subtriangular (Fig. 22 e); tergite X without vermiform setae, apical margin with three notches (Fig. 22 h) .................................................................................. 13
13 Males ........................................................................................................................................................ 14
- Females (not clearly distinguishable) ........ H. palawanensis / pseudopalawanensis Freitag & Jäch spp.n.
14 Main piece of aedeagus emarginate near insertion of right paramere; left paramere not longer than width of phallobase (Fig. 22 a) ................................................................. H. palawanensis Freitag & Jäch, sp. n.
- Main piece of aedeagus not emarginate near right paramere insertion; left paramere bent, distinctly longer than width of phallobase (Fig. 23 a) .................................... H. pseudopalawanensis Freitag & Jäch, sp. n.
description: Published as part of Freitag, Hendrik & Jäch, Manfred A., 2007, Revision of the species of Hydraena Kugelann (Coleoptera: Hydraenidae) from Palawan and Busuanga, with descriptions of eleven new species, and redescription of Hydraena (Hydraenopsis) scabra d'Orchymont, 1925, pp. 1-44 in Zootaxa 1431 on pages 5-6, DOI: 10.5281/zenodo.175790