A revision of Onychelmis Hinton, 1941 (Coleoptera: Elmidae), with description of new species, DNA barcoding and notes on the geography of the genus Author Linský, Marek E2AC74B9-FA5F-4D43-9168-4513D3E80A04 Zoology Lab, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK- 84523, Bratislava, Slovakia. & Department of Zoology, Faculty of Natural Science, Comenius University, Mlynská dolina B- 1, SK- 84215 Bratislava, Slovakia. marek.linsky@gmail.com Author Čiamporová-Zaťovičová, Zuzana 8D6A1FDB-06AB-44A7-B1F9-3FC86B7C9804 Zoology Lab, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK- 84523, Bratislava, Slovakia. & Department of Ecology, Faculty of Natural Science, Comenius University, Mlynská dolina B- 1, SK- 84215 Bratislava, Slovakia. zuzana.zatovicova@savba.sk Author Čiampor, Fedor 977CE415-B2E7-45DA-9DBE-B6D7CCCC58E4 Zoology Lab, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK- 84523, Bratislava, Slovakia. f.ciampor@savba.sk text European Journal of Taxonomy 2021 2021-03-11 739 1 1 35 http://dx.doi.org/10.5852/ejt.2021.739.1263 journal article 7762 10.5852/ejt.2021.739.1263 79e0ebb9-6412-4821-879a-9ec760579681 2118-9773 4600344 C333D3B5-7B4B-4A53-8548-E74DFEE9EBC2 Onychelmis longicollis ( Sharp, 1882 ) Figs 2 A–B, 6D, 7C–D, 12B Elmis longicollis Sharp, 1882: 138 . Onychelmis longicollis – Hinton 1941: 67 , figs 7–8. — Spangler & Santiago 1991: 497 , figs 3–4. — González-Córdoba et al. 2016: 11 , figs 5a–b, 7c–b. Differential diagnosis Onychelmis longicollis can be distinguished from all species of the genus by the combination of the following characters: 1) smaller size (CL: 1.27 mm ); 2) tomentum on profemora reaching behind middle, on mesofemora to around middle ( Fig. 6D ); 3) humeri feebly developed; 4) prominent carina on sixth elytral interval present; 5) elytral punctures moderately impressed; 6) shape of aedeagus lanceolate ( Fig. 7 C–D). Material examined Holotype PANAMA • ♂ ; “ Elmis longicollis Type D.S. V.de Chiriqui 4-6000ft. Panama . Champion // ♂ // Type [red disc] // V. de Chiriqui 4000-6000 ft. Champion. // B.C.A. Col. I. 2. Elmis longicollis Sharp. ”; NHM . Redescription Male ( holotype ) BODY. Obovate ( Fig. 2 A–B); length 1.27 mm ; width 0.60 mm ; dorsum conveX, glabrous. Body with sparse, light yellowish setae. Hairy or scale-like tomentum distributed on following areas: genae, sides of prosternum, mesoventrite, metaventrite and abdomen, epipleura, and medial and lateral portions of bases of femora. COLOUR. Head, pronotum and elytra black; venter dark brown with reddish tinge; trochanters, tibiae and tarsi brown; first two segments of antennae and tarsal claws pale brown. HEAD. Partly retractable into prothoraX. Antennae with only 2 segments remaining; pedicel about twice as long as scape. 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: 0.29 mm , ID: 0.14 mm , suboval in lateral view, protruding from head outline in dorsal view, circumocular surface raised. Frons convex between eyes. THORAX. Pronotum widest behind middle, PW: 0.41 mm , PL: 0.43 mm ; surface shiny, with narrow reticulation along basal margin and posterolateral angles, with dense tiny punctures; sublateral carinae absent, fine raised line indistinct; disc conveX, divided by a broad, deep transverse impression before middle; two prescutellar foveae separated by a raised line extending from base to apical discal half, connecting both 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 and 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, rugose, more or less shiny with setigerous punctures; disc convex with deep, medial, triangular depression in posterior half; discrimen in basal ¾; with one prebasal fovea on each side of metaventrite. Elytra (EL: 0.85 mm , EW: 0.60 mm ) conveX, widest in anterior ¾; sides strongly declivous; surface shiny, with dense tiny punctures; elytral margin narrowly rimmed; humeri feebly developed; epipleuron tapering posteriorly. Prominent carina on siXth interval well developed, reaching ⅘ of elytron. Elytra with ten rows of small punctures, moderately impressed, separated by 1–2 times puncture diameter, diminishing toward lateral margins and elytral apeX. Scutellum subovate, flat. Legs moderately long; femora clavate; tibiae longest, apically with cleaning fringes. 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. Fig. 2. Habitus of Onychelmis spp. A–B . O. longicollis ( Sharp, 1882 ) , holotype, ♂ (NHM). A . Dorsal view. B . Ventral view. C–D . O. whiteheadi Spangler & Santiago, 1991 , holotype, ♂ (NMNH). C . Dorsal view. D . Ventral view. Scale bar = 0.5 mm. ABDOMEN. With 5 ventrites. First ventrite with basal margin broadly rounded; fifth ventrite longest, apically setose, with posterior margin broadly arcuate. Aedeagus ( Fig. 7 C–D) elongate. Penis without fibula; corona in apical half; in ventral view conveX, from apical half tapering toward broad rounded apeX; in lateral view slender, evenly narrowed from base to slightly curved apeX. Parameres absent. Phallobase about 1.5 times as long as penis, subparallel, in ventral view straight, slightly curved in lateral view. Female Unknown. Distribution The species is reported from three countries ( Fig. 12B ), Colombia ( González-Córdoba et al. 2016 ), Nicaragua (Shepard pers. com.) and Panama ( Sharp 1882 ). However, the holotype , first illustrated herein, differs from the non-type O. longicollis from Colombia depicted in Spangler & Santiago (1991) and later followed by González-Córdoba et al. (2016) , and it is possible that they in fact represent different species, and therefore the correct distribution of O. longicollis needs to be reviewed. Remarks As stated by Sharp (1882) , the type specimen is in poor condition and some characters like tibial fringes, which Hinton (1941) incorrectly interpreted as plastron, are difficult to properly observe. Antennal segments 3–11, the left hind leg and the tarsus of the left mid leg are missing, the left elytron is broken, and the left foreleg is glued to the mounting point.