Liodessus caxamarca, Balke & Megna & Zenteno & Figueroa & Hendrich, 2020

Balke, Michael, Megna, Yoandri S., Zenteno, Nilver, Figueroa, Luis & Hendrich, Lars, 2020, Two new species of Liodessus Guignot, 1939 diving beetles from Northern Peru (Coleoptera, Dytiscidae, Hydroporinae), Alpine Entomology 4, pp. 173-178 : 173

Liodessus caxamarca sp. nov. Figs 1A-D , 2A , 3A-C , 4 , 5 , 6

Type locality.

Peru, Cajamarca, Encañada District, Conga, -6.934, -78.442.

Holotype.

Male (MUSM): Peru: Cajamarca, Cajamarca, Encañada District, Conga, 4030 m, 7.ix.2018, -6.934, -78.442, Y. S. Megna & N. Zenteno (PER_YSM_2018_46).

254 Paratypes (MUSM, ZSM). 100 exs.: same data as holotype; 30 exs.: Peru: Cajamarca, Cajamarca, Encañada District, Conga, 4013 m, 7.ix.2018, -6.95, -78.354, Y. S. Megna & N. Zenteno (PER_YSM_2018_45); 55 exs.: Peru: Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3928 m, 8.ix.2018, -6.887, -78.595, Y. S. Megna & N. Zenteno (PER_YSM_2018_47); 23 exs.: Peru: Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3947 m, 8.ix.2018, -6.892, -78.599, Y. S. Megna & N. Zenteno (PER_YSM_2018_48); 23 exs.: Peru: Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3961 m, 8.ix.2018, -6.894, -78.6, Y. S. Megna & N. Zenteno (PER_YSM_2018_49); 41 exs.: Peru: Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3933 m, 8.ix.2018, -6.902, -78.603, Y. S. Megna & N. Zenteno (PER_YSM_2018_50); 12 exs.: Peru: Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3935 m, 8.ix.2018, -6.91, -78.614, Y. S. Megna & N. Zenteno (PER_YSM_2018_51).

Description of holotype.

Habitus with distinct discontinuity between pronotum and elytra (as in Fig. 1D ). Total length: 2.8 mm; length without head 2.4 mm; maximum width: 1.3 mm.

Colouration.

Dark brown to blackish dorsally and ventrally (as in Fig. 1D ).

Surface sculpture.

Head more or less smooth and with few setiferous punctures in front of a faint cervical line, faint microreticulation present along sides of eyes; with distinct distinct microreticulation but without punctures posteriorly of occipital line. Pronotum and elytron shiny; with dense and coarse setiferous punctation.

Structures.

Antenna stout. Head with faint cervical line that dissolves into serial punctures laterally; with rounded clypeus. Pronotum with distinct lateral bead; with distinct and deep basal striae (as in Fig. 1D ). Elytron without obvious basal striae on left side and very short and inconspicuous on right hand side; without sutural line. Without basal epipleural transverse carina. Metathoracic wings short, about half the length of elytron (Fig. 2A ).

Genitalia.

Median lobe of aedeagus curved in lateral view, tip thin and appearing fragile; in ventral view slender and gently narrowed towards tip (Figs 3A, B ); lateral lobes (parameres) bisegmented and comparably broad (Fig. 3C ).

Variation.

Total length: 2.5-2.8 mm; length without head: 2.2-2.5 mm; maximum width: 1.1-1.4 mm. The elytral stria can be short yet well visible to very faint to absent. The color is rather variable, from comparably lightly colored (Fig. 1B ), to more or less dark brown to blackish (Figs 1A-D ). Specimens from localities #45 and #46 in Encañada District, Conga are overall darker than from the other localities. This is however not reflected in the haplotype tree we calculated from our cox1 data (Fig. 5 ). We assessed the length of the metathoracic wings in 10 specimens, which all had the same wing length. This does not rule out the possibility that a certain number of specimens can be fully winged.

Female.

Dorsal surface dull due to presence of well impressed microreticulation between surface punctation (Figs 1A-C , 2A ).

BOLD platform.

We provided 27 entries in the “COLLI” project, all retrieved in one cluster. Assignment to that cluster was unambiguous, meaning all specimens were correctly assigned to this morphologically delineated species.

Etymology.

Named after the Caxamarca pre Inca culture that inhabited the area between 200-1,300 AD, and also gave the name to the Department Cajamarca. The name is a noun in the nominative standing in apposition.

Comparative notes.

The species is well characterized by its size, discontinuous habitus, shape of male genitalia (Figs 3A, B ) and cox1 signature.

Distribution.

Only known from the high Andes in north western Peru (Fig. 4 ).

Habitat.

Shallow and exposed peatland puddles, collected with strainer out of mats of vegetation including mosses (Fig. 6 ).

Figures

Figure 1. Liodessus spp.: Dorsal habitus of Liodessus caxamarca sp. nov., female paratypes from locality PER _ YSM _ 2018 _ 046 (A), PER _ YSM _ 2018 _ 047 (B), PER _ YSM _ 2018 _ 046 (C), male paratype PER _ YSM _ 2018 _ 046 (D); Liodessus altoperuensis sp. nov., male paratype from locality PER _ YSM _ 2018 _ 050 (E).

Figure 2. Liodessus spp., female paratypes: Metathoracic wing of paratypes of Liodessus caxamarca sp. nov. (A); Liodessus altoperuensis sp. nov. (B).

Figure 3. Liodessus spp. males: Liodessus caxamarca sp. nov., holotype, median lobe of aedeagus in ventral view (A), same in lateral view (B), right paramere external surface view (C); Liodessus altoperuensis sp. nov. holotype, median lobe of aedeagus in ventral view (D), same in lateral view (E), right paramere external surface view (F).

Figure 4. Distribution area (orange dot) of Liodessus caxamarca sp. nov. and Liodessus altoperuensis sp. nov. in the northern Andes of Peru.

Figure 5. Localities of Liodessus caxamarca sp. nov. sampled for cox 1 data, and haplotype tree inferred using TCS software. Each bar along the lines connecting the 5 haplotypes indicates one inferred nucleotide substitution. The base map was taken from GoogleEarth.

Figure 6. Habitats and landscapes at localities Cajamarca, Cajamarca, Encanada District, Conga, 4030 m [PER _ YSM _ 2018 _ 046] (A, B) and Cajamarca, San Pablo, Tumbaden District, Alto Peru, 3935 m [PER _ YSM _ 2018 _ 51] (C, D).