Hydaticus (Prodaticus)

Megna, Yoandri S., Balke, Michael, Apenborn, Rico & Hendrich, Lars, 2019, A review of Peruvian diving beetles of the genus Hydaticus Leach, 1817, with description of Hydaticus (Prodaticus) panguana sp. nov. and notes on other Neotropical species (Coleoptera: Dytiscidae), Zootaxa 4615 (1), pp. 113-130 : 127-128

Key to the species of subgenus Hydaticus (Prodaticus) of the Neotropical Region

1. Elytron with a transverse and subbasal yellowish fascia ( Fig. 1 . Tbf)............................................. 2

- Elytron without a transverse and subbasal yellowish fascia ( Fig. 2A )............................................. 5

2. Pronotum yellowish with a black band on anterior and posterior margin ( Fig. 1 , Abb, Pbb)............................ 4

- Pronotum black with broad yellowish lateral margins ( Fig. 2B )................................................. 3

3. Elytron with basal fasciae confluent with sublateral, longitudinal and yellowish stripes; elytron without a subtriangular, postmedial and broad spot.......................................................................... H. devexus

- Elytron usually with basal fasciae not confluent with sublateral, longitudinal and yellowish stripes; elytron with a subtriangular, postmedial and broad spot ( Fig. 2B )............................................................... H. lateralis

4. TL 11.4–12.6 mm; pronotum with basal black band narrowly extended to anterior margin; elytron without sublateral yellow stripes, and with a large lateral spot just behind middle; apical third largely irrorated; protarsomere I with a series of spines across the dorsal surface; metatibia with bifid setae not parallel to dorsal margin on posterior surface ( Fig. 2C ).................................................................................................... H. subfasciatus

- TL 9.6–10.4 mm; pronotum with basal black band not extended; elytron with sublateral and lateral yellow stripes, and without lateral spots; apical third largely rufous ( Fig. 3D ); protarsomere I without a series of spines across the dorsal surface; metatibia with bifid setae parallel to dorsal margin on posterior surface....................................... H. xanthomelas

5. Pronotum black with yellowish lateral margins ( Fig. 2A )...................................................... 6

- Pronotum yellowish with a black band on anterior and posterior margin ( Fig. 1 , Abb, Pbb)............................ 7

6. Elytron with lateral, longitudinal and yellowish stripes, and without a subtriangular, postmedial and broad spot.. H. tuyuensis

- Elytron without lateral, longitudinal and yellowish stripes, and with a subtriangular, postmedial and broad spot ( Fig. 2A )...................................................................................... H. panguana sp. nov.

7. Protarsus without accessory medial spinous setae on dorsal surface of basal tarsomere of male; elytron without lateral yellow stripes..................................................................................... H. fractivittis

- Protarsus with accessory medial spinous setae on dorsal surface of basal tarsomere of male; elytron with lateral yellow stripes ( Fig. 1 , Ls)........................................................................................... 8

8. Distribution: Colombia, Ecuador, Brazil, Paraguay and Argentina median lobe of aedeagus rounded apically in lateral view... ................................................................................................... 9

- Distribution: USA, Central America and West Indies; median lobe of aedeagus angulate or truncated apically in lateral view. .................................................................................................. 10

9. TL 10.8–12.5 mm; epipenite with apex rounded; median lobe of aedeagus in apical third greatly widened and rounded in dorsal view.................................................................................. H. inexspectatus

- TL 13.0– 13.6 mm; epipenite with apex acute; median lobe of aedeagus in apical third subparallel and slightly rounded in dorsal view....................................................................................... H. palliatus

10. Median lobe of aedeagus angulate at apex in lateral view; each elytron with a definite and regular submarginal yellow stripe, more or less recurved at the base, without inward extensions; posterior black band of pronotum usually restricted to basal third; anterior disc of metatibiae generally with more than 10 large spines.................................. H. bimarginatus

- Median lobe of aedeagus truncate apically in lateral view; each elytron with a submarginal stripe usually broad, sometimes with inward extensions ( Fig. 3C ); posterior black band of pronotum often extended to or almost to anterior margin; anterior disc of metatibiae generally with less than 10 large spines.................................................... H. rimosus

Figures

FIGURE 1. Dorsal view of the colour pattern of a generalized Hydaticus for the Neotropical region. Head (He): Ptbb-posterior transverse black band. Pronotum (Pr): Abb- anterior black band; Pbb-posterior black band; Plaa- posterior lateral angle acute. Scutellum (Sc). Elytron (El): Ai- apex irrorated; Bs- basal spot; Ls- lateral yellow stripes; Ms- middle spot; Sls- Subbasal and lateral yellow stripe; Tbf- transverse basal fasciae; Tpi- third posterior irrorated.

FIGURE 2. Dorsal habitus of H. panguana sp. nov. (A), H. lateralis (B), H. subfasciatus (C) and H. xanthomelas (D). All specimens collected in Panguana, Peru. Scale bar = 5 mm.

FIGURE 3. Dorsal habitus of H. fractivittis (A) and H. palliatus (B), both from Paraguay, and H. rimosus (C) from Guatemala. Scale bar = 5 mm.