Hydrochus collaris

Perkins, Philip D., 2021, Taxonomy of water beetles in the genus Hydrochus Leach, 1817, from Bolivia, Brazil and Paraguay (Coleoptera: Hydrochidae), Zootaxa 4994 (1), pp. 1-93 : 12

H. collaris species group

Figs. 3 , 4 , 5 , 30 , 42 , 54 , 70

Members of the H. collaris species group are recognized by the combination of the following characteristics: 1) medium sized species, length ca. 2.70–3.80 mm, with a deep cervical groove behind the eyes, into which the anterior margin of the pronotum fits; 2) dorsum densely punctate, often with iridescence; 3) pronotum often rather elongate; 4) male genitalia elongate, parameres often blunt apically, lacking subapical lateral angle. Seven species are now included in the group, which is restricted to South America ( Fig. 54 ): H. astrictus , H. bisinuatus , H. canalis , H. collaris , H. conjunctus , H. lobissimus , and H. purpureus . Another species, H. battjai Makhan from Suriname is also a member of the species group, but a revision of this area has not yet been published, because type specimens were not deposited in a museum.

Figures

FIGURE 3. Dorsal habitus of Hydrochus species in study area.

FIGURE 4. Dorsal habitus of Hydrochus species in study area.

FIGURE 5. Dorsal habitus of Hydrochus species in study area.

FIGURE 70. Pictorial aid to species groups of Hydrochus from Bolivia, Brazil and Paraguay, using male genitalia. Not to same scale.

FIGURES 30–31. Habitus and male genitalia of holotypes. 30. Hydrochus canalis n. sp. 31. Hydrochus trituberculatus n. sp.

FIGURES 42–43. Habitus and male genitalia. 42. Hydrochus astrictus Perkins. 43. Hydrochus pietersenae Makhan.

FIGURES 53–54. Geographical distributions. 53. H spanglerorum species group. 54. H collaris species group.