Onychelmis lenkae, Linský & Čiamporová-Zaťovičová & Čiampor, 2021

Linský, Marek, Čiamporová-Zaťovičová, Zuzana & Čiampor, Fedor, 2021, A revision of Onychelmis Hinton, 1941 (Coleoptera: Elmidae), with description of new species, DNA barcoding and notes on the geography of the genus, European Journal of Taxonomy 739 (1), pp. 1-35 : 25-26

publication ID

https://doi.org/ 10.5852/ejt.2021.739.1263

publication LSID




persistent identifier


taxon LSID


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scientific name

Onychelmis lenkae

sp. nov.

Onychelmis lenkae sp. nov.


Figs 3E View Fig , 5A, C View Fig , 6B View Fig , 10 View Fig A–B, 11B, 12A–B

Differential diagnosis

Onychelmis lenkae sp. nov. can be distinguished from all species of the genus by the combination of the following characters: 1) smaller size (CL: 1.24–1.28 mm); 2) pro- and mesofemora with tomentum reaching to around middle ( Fig. 6B View Fig ); 3) humeri produced; 4) prominent carina on sixth interval present; 5) elytral punctures absent; 6) shape of aedeagus lanceolate ( Fig. 10 View Fig A–B).


This species is named after daughter of ZČZ and FČ, Lenka Čiamporová. She helped a lot during collecting in Ecuador although she was only five at the time.

Material examined

Holotype ECUADOR • ♂; “Ecuador, Napo prov., road to Coca, 00°43′39.6″ S, 77°45′56.1″ W, 1129 m a.s.l., 17. 8. 2013, small stream below waterfall, Čiampor & Čiamporová-Zaťovičová lgt. ”; PUCE. GoogleMaps

Paratypes ECUADOR • 5 ♂♂, 5 ♀♀; same collection data as for holotype; PUCE / CCB GoogleMaps .

Other material

ECUADOR • 1 ♂, 1 larva; same collection data as for holotype; CCB GoogleMaps .



BODY. Obovate ( Fig. 3E View Fig ), dorsally black, ventrally brown; length 1.24–1.28 mm; width 0.57–0.61 mm; dorsum convex, glabrous with sparse, light yellowish-brown setae. Hairy or scale-like tomentum distributed on following areas: genae, sides of prosternum, mesoventrite, metaventrite and abdomen, epipleura, and medial and lateral portions on bases of femora.

COLOUR. Head, pronotum and elytra black; venter dark brown to black with reddish tinge; coxae, femora and tarsi dark brown with reddish tinge; trochanters and tibiae brown; basal segments of antennae and tarsal claws pale brown.

HEAD. Partly retractable into prothoraX, dorsally shiny. Antennae filiform, 11-segmented; pedicel about twice as long as scape; remaining segments about 4 times as long as scape and pedicel combined; segments 3–10 subrectangular, subequal in length; terminal segment longest, suboval, with pointed apex. Labrum with anterior margin almost straight; anterolateral angles broadly arcuate with numerous golden, recumbent hair-like setae; clypeus shorter and wider than labrum, about 3.5 times as wide as long, anterior margin slightly concave, anterolateral angles rounded; frontoclypeal suture almost straight. Eyes well developed, HW: 0.28–0.30 mm, ID: 0.15–0.16 mm, suboval in lateral view, protruding from head outline in dorsal view, circumocular surface raised. Frons between eyes convex.

THORAX. Pronotum widest behind middle, PW: 0.38–0.40 mm, PL: 0.46–0.48 mm; surface shiny, with narrow reticulation along basal margin and posterolateral angles, with dense tiny punctures; sublateral carinae never well-developed, but a short, very fine raised line in basal ½ present; disc conveX, divided by broad, deep transverse impression before middle; two prescutellar foveae separated by a raised line extending from base to discal half, connecting pronotal halves and merging into them; anterior margin arcuate; posterior margin bisinuate; sides of pronotum convex before and after transverse constriction; lateral margins narrowly rimmed; posterolateral angles orthogonal; anterolateral angles slightly produced. Hypomeron finely microreticulate, widest in middle. Prosternum moderately long in front of procoxae, with anterior margin concave; sides raised around procoxae, forming carinae, not reaching anterior margin, prosternal process long, moderately broad, with posterior margin broadly rounded. Mesoventrite coarse, short and wide, with deep triangular groove for reception of prosternal process; posterior margin around mesocoxae raised. Metaventrite slightly wider than long, shiny with setigerous punctures; disc convex with moderately deep, medial, triangular depression in posterior half; discrimen in basal ¾, very thin, almost indistinct; with prebasal fovea on each side ( Fig. 5A, C View Fig ). Elytra (EL: 0.77–0.81 mm, EW: 0.57–0.61 mm) conveX, widest in anterior ¾; sides strongly declivous; surface shiny, with tiny punctures; elytral margin narrowly rimmed; humeri protruding from outline; epipleuron tapering posteriorly. Prominent carina on siXth interval reaching ⅘ of elytron; strial punctures absent (in a few specimens a partial striation is present). Scutellum subovate, flat. Legs moderately long; femora clavate; tibiae longest. Protibiae with anterior cleaning fringe on apical ⅓; mesotibiae with two cleaning fringes – anterior on apical ⅕ and posterior on apical ⅓; metatibiae with posterior cleaning fringe on apical ⅓. Tarsi 5-segmented, first four segments each with one fine pale, recumbent seta, fifth segment slightly shorter than remaining segments combined; claws with a large subbasal and smaller basal teeth.

ABDOMEN. With 5 ventrites. First ventrite with basal margin broadly rounded; fifth ventrite longest, apically setose, with posterior margin broadly arcuate. Aedeagus ( Fig. 10 View Fig A–B) elongate. Penis without fibula; corona in apical half; in ventral view subparallel with apeX rounded; in lateral view curved, evenly narrowed from base to apeX. Parameres absent. Phallobase slightly longer than penis, parallelsided, in ventral view straight, curved in lateral view.


Externally similar to male, except metaventrite without distinct medial, triangular depression in posterior half and without two prebasal foveae, fifth ventrite more elongate.


Collected from small stream directly below waterfall surrounded by remnants of primary forest, with water flowing between larger stones ( Fig. 11B View Fig ).


Known only from the type locality in Napo Province ( Figs 11B View Fig , 12 View Fig A–B).


Central College, Bangalore













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