Liodessus venezuelanus, Balke & Bilton & García & Viloria & Villastrigo & Hendrich, 2022

Balke, Michael, Bilton, David T., Garcia, Mauricio, Viloria, Angel L., Villastrigo, Adrian & Hendrich, Lars, 2022, Two new high Andean species of Liodessus diving beetles from Venezuela (Coleoptera, Dytiscidae, Bidessini), Alpine Entomology 6, pp. 7-12 : 7

Liodessus venezuelanus sp. nov.

Figures 1B , 2C, D , 3B , 4

Type locality.

Laguna de Mucubají, Mérida, Venezuela.

Type material.

Holotype: Male: Venezuela; Mérida, Laguna de Mucubají, 3,500 m, i.2004, 8.7964, -70.8255, García & Balke" ( MIZA). Paratypes: 1 ex. same label data as holotype ( ZSM); 8 exs Venezuela: Mérida, Pico Bolívar, Laguna de Gallo, 4,000 m, 6.XII.1998, 8.5269, -71.0722, Bilton (CBP, ZSM); 3 exs Venezuela: Mérida, ca. 5 km E Gavidia, 3,600 m, 23.I.2012, 8.6895, -70.8817, Short, Arias & Gustafson, lagoon margin, VZ12-0123-03A ( MIZA, SEMC).

Description.

Habitus with more evident discontinuity between pronotum and elytron (Fig. 1B ), pronotum widest before base and more rounded laterally (Fig. 1B ). Total length 2.2 mm; length without head 2.0 mm; maximum width 1.0 mm.

Color. Very dark brown to blackish dorsally and ventrally, basal antennomeres, base of meso- and metatibia contrastingly of lighter color (Figs 1B , 2C, D ).

Surface sculpture. Head with few larger and smaller setiferous punctures (Figs 1B , 2C, D ); with distinct microreticulation except on middle of head between the eyes. Pronotum and elytron shiny; with moderately dense and coarse setiferous punctation (Fig. 1B ).

Structures. Antenna stout. Head with occipital line; with rounded clypeus. Pronotum with distinct lateral beads; with distinct long and deep basal striae (Figs 1A, B ). Elytron with short basal stria; without sutural line; without basal epipleural transverse carina. Metathoracic wings not examined in holotype (in paratype: short, about half the length of elytron).

Genitalia. Median lobe of aedeagus broadened towards apex, then narrowing in lateral view; also broadening towards tip in ventral view, tip broadly rounded; parameres of simple " Bidessini " type, two segmented (Fig. 3B ).

Female. Pronotum and/or elytra microreticulate, dull (specimens from Laguna de Gallo); shiny in the single females from Laguna Mucabají and Gavidia.

Variation. Size variation of the paratypes is TL 2.0-2.3 mm; TL-h 1.8-2.0 mm; MW 0.9-1.1 mm. In few paratypes, the elytral basal stria is not very obvious.

Etymology.

Named after the country of origin. The name is an adjective in the nominative singular.

Comparative notes.

Distinguished from other species of Liodessus by the diagnostic combination of the following features: Species from Venezuela; beetle relatively small (TL 2.0-2.3 mm); very dark brown to blackish; head without occipital line; pronotal and elytral striae present; wings reduced considerably; shape of median lobe (broad in lateral and ventral view, with its particular shape).

BOLD platform.

We provided 1 entry to our BOLD Liodessus project. The species is well delineated from all other Liodessus , with an uncorrected p-distance of around 8% or more.

Distribution.

Known from around Mérida, Venezuela.

Habitat.

Collected from shallow water at the edge of high-altitude ponds (Fig. 4 ).

Checklist of the High Andean species of Liodessus Guignot, 1953

1. Liodessus acollensis Guignot, 1955: Peru

2. Liodessus alpinus Balke et al., 2020a: Peru

3. Liodessus altoperuensis Balke et al., 2020b: Peru

4. Liodessus andinus Guignot, 1957: Bolivia

5. Liodessus azufralis Megna et al., 2019: Colombia

6. Liodessus bogotensis Guignot, 1953: Colombia

7. Liodessus caxamarca Balke et al., 2020b: Peru

8. Liodessus hauthi Balke et al., 2020a: Peru

9. Liodessus lacunaviridis Balke et al., 2020a: Colombia

10. Liodessus picinus Balke et al., 2021: Colombia

11a. Liodessus quillacinga quillacinga Megna et al., 2019: Colombia

11b. Liodessus quillacinga cochaensis Megna et al., 2019: Colombia

11c. Liodessus quillacinga cumbalis Megna et al., 2019: Colombia

12. Liodessus quimbaya Megna et al., 2019: Colombia

13. Liodessus rhigos Balke et al., 2020a: Peru

14. Liodessus thespesios Balke et al., 2020a: Peru

15. Liodessus meridensis sp. nov.: Venezuela

16. Liodessus venezuelanus sp. nov.: Venezuela

Figures

Figure 1. Dorsal habitus of Liodessus spp. nov. L. meridensis (A); L. venezuelanus (B). Scale bar: 2 mm.

Figure 2. Liodessus spp. nov. Detail of head in dorsal view. L. meridensis (A, B); L. venezuelanus (C, D).

Figure 3. Liodessus spp. nov. Median lobe ventral and lateral views; parameres outer and inner surfaces, L. meridensis (A); L. venezuelanus (B). Scale bar: 0.5 mm.

Figure 4. Habitat of Liodessus spp. nov. near Gavidia, Venenzuela, where both new species were collected (collecting event VZ 10 - 0123 - 03 A). Overview (A); detail of shallow water at the edge (B).