Liodessus alpinus Balke & Megna & Zenteno & Figueroa & Hendrich 2020, sp. nov.
Creators: name: Balke, Michael
name: Megna, Yoandri S.
name: Zenteno, Nilver
name: Figueroa, Luis
name: Hendrich, Lars
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dytiscidae
Liodessus
Liodessus alpinus

description: Liodessus alpinus sp. nov.
(Figs 2A, B, 4C, 5C, E, 7)
Type locality. Peru: Junín, Junín, Lagoon Estancia Azulmito, 4,452 m, -11.303° -75.989°.
Type material. Holotype: Male (MUSM): “ Peru: Junín, Junín, Lagoon Estancia Azulmito, 4452 m, 14.viii.2018, -11.303° -75.989°, Y. S. Megna & N. Zenteno (PER _YSM_2018_14)”; “ Holotype Liodessus alpinus sp. nov. Balke, Megna, Hendrich des. 2020” [red printed label].
85 Paratypes (MUSM, ZSM): 5 exs.: same data as holotype; 55 exs.: “ Peru: Junín, Junín, Shalacancha, 4600 m, 11.viii.2018, -11.09° -75.879°, Y. S. Megna & N. Zenteno (PER _YSM_2018_09)”; 2 exs.: “ Peru: Junín, Junín, Shalacancha, 4320 m, 11.viii.2018, -11.075° -75.863°, Y. S. Megna & N. Zenteno (PER _YSM_2018_10)”; 15 exs.: “ Peru: Junín, Junín, Junín, 4099 m, 12.viii.2018, -11.164° -76.008°, Y. S. Megna & N. Zenteno (PER _YSM_ 2018_11)”; 18 exs.: “ Peru: Junín, Junín, Shoqui, 4324 m, 15.viii.2018, -11.046° -75.897°, Y. S. Megna & N. Zenteno (PER _YSM_2018_18)”; 7 exs.: “ Peru: Cusco, Canchis, Checacupe, Cayena, 4906 m, 25.viii.2018, -14.009° -71.067°, Y. S. Megna & N. Zenteno (PER _YSM_2018_28)”. All paratypes are provided with our red printed paratype labels.
Description of holotype. Habitus with distinct discontinuity between pronotum and elytra; broadest at about 1/3 of elytral length and body therefore appearing slightly pear shaped (as in Figs 2A, B). TL: 2.0 mm; TL-H: 1.7 mm; TW: 0.9 mm.
Colouration. Mostly blackish dorsally and ventrally (as in Figs 2A, B).
Surface sculpture. Head with faint microreticulation at base and along hind angles of eyes, frons and clypeus more or less smooth and with few fine setiferous punctures; pronotum shiny with with sparser and fine setiferous punctation; elytra shiny with dense and coarser setiferous punctation.
Structures. Antenna stout. Head without cervical line but few serial punctures instead. Pronotum on each lateral side (or margin) with distinct bead and with distinct and deep basal plicae. Elytron with short and faint basal plicae only visible using diffuse lateral lighting. Metathoracic wings short, about half the length of elytron.
Genitalia. Median lobe of aedeagus thick, bulky in lateral view, tip with short nose which is also prominent in ventral view, dorsally on both sides at about mid-length with shallow lateral keels; lateral lobes (parameres) with distal part longish (Fig. 4C).
Variation. TL: 2.0– 2.2 mm; TL-H: 1.7–1.8 mm; TW: 0.9–1.0 mm. Few specimens show an extremely faint, interrupted cervical line. We assessed the length of the metathoracic wings in 10 specimens, which all had the same short wing length. While these specimens are certainly not able to fly actively, there might be few fully winged individuals that are capable of flight.
Female. Dorsal surface as in male, few specimens with more or less extensive microreticulation on clypeus and along eyes, pronotal disc and laterally as well as on elytron apically only or from about basal 1/3 up to apex (dullest form depicted in Fig. 2B).
BOLD platform. We provided 17 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. The specific name is the Latin adjective alpinus (of high mountains).
Distribution. High Andes of central and southeastern Peru (Fig. 7), ca. 4,300 –4,900 m.
Habitat. Shallow and exposed puddles, collected with strainer out of mats of vegetation (Fig.5C, E). Other Dytiscidae associated with this species were species of Rhantus Dejean, 1833 and Lancetes Sharp, 1882, as well as Liodessus acollensis.
description: Published as part of Balke, Michael, Megna, Yoandri S., Zenteno, Nilver, Figueroa, Luis & Hendrich, Lars, 2020, New Liodessus species from the high Andes of Peru (Coleoptera: Dytiscidae Bidessini), pp. 151-165 in Zootaxa 4852 (2) on page 155, DOI: 10.11646/zootaxa.4852.2.1, http://zenodo.org/record/4519043