Molecular phylogeny of the riffle beetle genus Hexanchorus revealed a presence of a new genus (Coleoptera: Elmidae) Author Linsky, Marek https://orcid.org/0000-0001-7206-2380 Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Du ́ bravska ́ cesta 9, SK- 84523, Bratislava, Slovakia & Department of Zoology, Faculty of Natural Sciences, Comenius University, Mlynska ́ dolina B- 1, SK- 84215 Bratislava, Slovakia Author Ciamporova-Zatovicova, Zuzana https://orcid.org/0000-0003-0506-6212 Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Du ́ bravska ́ cesta 9, SK- 84523, Bratislava, Slovakia & Department of Zoology, Faculty of Natural Sciences, Comenius University, Mlynska ́ dolina B- 1, SK- 84215 Bratislava, Slovakia Author Lassova, Kristina https://orcid.org/0000-0002-7175-2109 Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Du ́ bravska ́ cesta 9, SK- 84523, Bratislava, Slovakia Author Ciampor Jr, Fedor https://orcid.org/0000-0001-6269-3592 Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Du ́ bravska ́ cesta 9, SK- 84523, Bratislava, Slovakia & Department of Zoology, Faculty of Natural Sciences, Comenius University, Mlynska ́ dolina B- 1, SK- 84215 Bratislava, Slovakia f.ciampor@savba.sk text Arthropod Systematics & amp; Phylogeny 2022 2022-11-18 80 575 602 http://dx.doi.org/10.3897/asp.80.e84013 journal article http://dx.doi.org/10.3897/asp.80.e84013 1864-8312-80-575 4A6669D57DDD4AE0A8B455724B9C594A 81B59BA932BC5DAF90815FD08F5820A6 3.2.2. Rumilara gen. nov. Type species. Rumilara obscura sp. nov. Diagnosis. A new genus is recognized by the combination of the following characters: compact structure of antennae (Fig. 5a-e ); mandibles with teeth fused (Fig. 4b ); surface of pronotum microreticulate, with complete transverse impression before middle, outline of discal area elevated, partially or fully interrupted medially by a prescutellar indentation (Fig. 6 ), mesotibiae without pubescence on lateral sides, without tubercle on inner apex in males; fourth tarsomere with apicoventral, long, erect seta; abdomen convex, with apical segment rounded in both sexes (Fig. 8 ). Figure 2. Dorsal habiti of Rumilara gen. nov. species: a R. obscura sp. nov. male holotype; b R. suppressa sp. nov. male holotype; c R. riberai sp. nov. male holotype; d R. paterna sp. nov. male holotype; e R. leleupi comb. nov. male holotype. Scale: 0.5mm. Figure 3. Lateral habiti of Rumilara gen. nov. species. a R. obscura sp. nov. male holotype; b R. suppressa sp. nov. male holotype; c R. riberai sp. nov. male holotype; d R. paterna sp. nov. male holotype; e R. leleupi comb. nov. male holotype. Scale: 0.5mm. Description. Body elongate (Figs 2 - 3 ), 2.44-3.28 mm long, subparallel, widest near posterior fifth of elytra (EW), 0.83-1.37 mm wide, dorsum moderately convex. Dorsal surface covered, at least partially, with two types of setae: 1) short, prone, more or less densely pubescent, and 2) numerous moderately long, curved, semi-erect, hair-like. Ventral surface clothed with yellowish, densely set, short to moderately long, recumbent pubescence that is confined partly or fully to following areas: genae, ventral face of head, hypomera, epipleura, prosternum, mesoventrite, metaventrite, abdomen, coxae, trochanters, femora, tibiae and tarsi. Head narrower than pronotum, retractile, dorsally moderately convex, laterally rounded, ventrally nearly flat. Surface microreticulate, with fine sparse or very dense punctation partly or fully concealed by pubescence. Eyes well developed, hemispherical; with row of long, hair-like setae along dorsal margin (often peeled off in R. riberai sp. nov. and R. suppressa sp. nov. specimens). Labrum about 3 times wider than long; transverse; with row of long, yellowish, hair-like setae near anterior margin; anterolateral angles rounded; surface glabrous; anterior margin feebly emarginate medially. Clypeus shorter than labrum, transverse, surface microreticulate, fully or not at all concealed by pubescence, anterior margin with a row of moderately long, hair-like setae; frontoclypeal suture straight. Antennae (Fig. 5a-e ) 11-segmented; clubbed, club ca. twice as long as combined length of scape and pedicel. Scape curved, ca. 1.5 times as long as pedicel; pedicel subglobular. Segment 3 subtriangular, longer than wide; segment 4 about as long as wide; segments 5 to 10 wider than long, transverse; segment 11 about as long as wide, subglobular. All segments densely clothed with short, prone setae; scape and pedicel also with long, stout, hair-like setae; segments 5 to 11 with a few erect, hair-like setae. Mandible (Fig. 4b ) short, moderately broad, nearly symmetrical with apical teeth fused; outer lateral margin strongly curved at base with a few long, curved, hair-like setae; ventral condyle bearing row of long, hair-like setae; molar part large, finely grooved. Prostheca hyaline, long, with numerous apical finger-like outgrowths. Maxilla (Fig. 4c ) with cardo densely clothed with hair-like setae; stipes subtriangular, with moderately long, densely arranged, hair-like setae; palpifer nearly half as long as stipes, with moderately long, hair-like setae on external face, and with long, hair-like setae near anterior margin. Maxillary palpi 4-segmented; surface of segments 2 and 3 obscured by densely arranged, moderately long, hair-like setae; segment 1 very short, about as long as wide; segment 2 about twice as long as wide, widening apically; segment 3 slightly longer than the previous segment; terminal segment longest. Galea elongate, external outline convex, inner outline concave; apex rounded, with numerous slightly longer, finger-like setae; outer outline densely clothed with long, hair-like setae. Lacinia about twice as wide as galea, longer than wide, subrectangular; clothed with long, densely arranged, hair-like setae and apically with transverse rows of stout, bent, finger-like setae. Labium (Fig. 4d ) with palpiger short, clothed with tuft of very long, densely set, hair-like setae. Labial palpi 3-segmented; segments 1 and 2 subequal in length, with tuft of conspicuous, long, hair-like setae; terminal segment largest, suboval, widest apically, apex truncate, with a field of short, finger-like setae. Ligula almost as long as palpi, widest anteriorly; anterolateral angles broadly rounded; anterior and anterolateral margin with densely arranged, moderately long, curved, hair-like setae; medial portion covered with short, stout, finger-like setae. Prementum short, transverse, widest posteriorly; mentum longer then prementum, densely clothed with long, semi-erect, hair-like setae. Thorax . Pronotum (Fig. 6 ) wider than long, subparallel, widest near middle; disc convex, posteriorly to transverse impression distinctly elevated, partially of fully interrupted medially by prescutellar indentation, surface microreticulate; with broad transverse impression in anterior third; sublateral carinae absent; with arcuate impression near posterolateral sides; anterior margin arcuate; anterolateral angles rounded; lateral margins almost straight in anterior third then broadly rounded; posterior margin trisinuate, broadly arcuate on each side and narrowly in front of scutellum; posterior angles suborthogonal. Surface microreticulate (feebly visible in R. leleupi comb. nov. ). Hypomeron widest in anterior third, then distinctly narrowed, almost straight. Prosternum (Fig. 7 ) extremely short in front of procoxae; procoxae strongly transverse in lateral view; prosternal process wide; parallel-sided between procoxae, then straight or concavely tapering towards rounded apex. Mesoventrite short and wide, with deep narrow groove for reception of prosternal process. Metaventrite slightly wider than long, moderately smooth, disc convex with a narrow longitudinal impression on midline. Elytra elongate, parallel or finely subparallel, widest in posterior 4/5, then evenly arched towards rounded apex. Each elytron with 10 rows of shallowly to deeply impressed punctures. Intervals nearly flat, slightly elevated or partly depressed. Scutellum wider than long, rounded. Epipleuron oblique until posterior margin of metaventrite then inflexed horizontally, posteriorly tapering, not reaching elytral apex. Hind wing without radial cross vein; without anal cell; with first and second branches of anal vein 2 fused; anal vein 1 present only apically; cubito-anal cross vein incomplete or complete and joining cubitus to anal vein 1. Legs long, at least partially covered by pubescence; femora widest across middle; tibiae moderately bent, subequal in length with femora. Tarsi 5-segmented, fourth segment with an apicoventral, long, erect seta, fifth segment slightly shorter than remaining segments combined; claws strong, long, without basal or subbasal teeth. Abdomen (Fig. 8 ) with 5 ventrites; first ventrite with intercoxal process subtriangular, about twice as wide as long, feebly incissed medially; ventrites 2-4 gradually shorter and slightly narrower than previous one; posterior margin of ventrite 5 broadly rounded. Male . Sternite VIII (Figs 11e , 12e , 13e , 14d , 15d ) with long, rather wide medial apodeme; apically broadly bisinuate, densely set with moderately long, curved, semi-erect, hair-like setae. Aedeagus of trilobate type; long and slender; penis long, tapering apically, corona present, with or without long, dorsal, rod-like sclerite, membranous sack with one smaller and one large, oblong ventral sclerites; parameres feebly to strongly asymmetrical, reaching from below half to 4/5 of penis; phallobase longer than penis. Female . Sternite VIII (Figs 11f , 12f , 13f ) with long, narrow, medial apodeme; apically broadly bi- or quadrisinuate, densely set with moderately long, curved, semi-erect hairs. Ovipositor (Figs 11d , 12d , 13d ) with coxites and styli short; coxites broad at base; struts long and slender. Figure 4. Mouthparts of Hexanchorus cordillierae ( a ) and Rumilara obscura sp. nov. ( b - i ); a adult mandible; b adult mandible; c adult maxilla; d adult labium (right palp omitted); e larval mandible; f larval antenna; g larval labrum; h larval labium; i larval maxilla. Scale: 0.1mm. Figure 5. Antennae of Rumilara gen. nov. and Hexanchorus : a R. obscura sp. nov. ; b R. suppressa sp. nov. ; c R. riberai sp. nov. ; d R. paterna sp. nov. ; e R. leleupi comb. nov. ; f H. mcdiarmidi ; g H. virilis ; h H. shannoni ; i H. angeli ; j H. rostratus ; k H. cordillierae ; l H. onorei ; m H. tarsalis ; n H. usitatus ; o H. gracilipes ; p H. caraibus ; q H. crinitus ; r H. dimorphus ; s H. emarginatus ; t H. browni . (a, k based on dissected antennae; b-j, l-r based on photographs, not to scale, setae omitted). Etymology. The name of the genus is inspired by the language of the indigenous Quechua people who live in the territory where the new genus originated. In the Quechua language ( Gomez Rendon 2009 ), " rumi " means rock, referring to the nature of the type locality and other habitats of the species, i.e., steep rocks with water flowing in thin layer, or fast-flowing streams with bottoms composed largely of larger rocks. The adjective ' lara ' refers to type-genus of the subfamily Larainae . Gender feminine. Figure 6. Pronota of Rumilara gen. nov. species: a R. obscura sp. nov. male holotype; b R. suppressa sp. nov. male holotype; c R. riberai sp. nov. male holotype; d R. paterna sp. nov. male holotype; e R. leleupi comb. nov. male holotype. Scale: 0.2mm. Distribution. The genus is distributed in central Ecuador, so far known from four provinces (Cotopaxi Province, Napo Province, Morona-Santiago Province, Santo Domingo de los Tsachilas Province). Comparative notes. The new genus is the closest to Hexanchorus , both share a combination of following synapomorphies which separate them from remaining Larainae genera: smaller body size (length never reaches 5 mm); pronotum with distinct transverse impression in anterior half; hind wing venation without anal cell; apex of fourth tarsal segment ventrally with a fine nearly erect seta; and membranous sac of penis with laterally placed fibula. Adults of Rumilara gen. nov. differs from Hexanchorus mainly in: (i) microreticulate pronotum (Fig. 6 ) (less distinct in R. leleupi comb. nov. ); outline of discal area elevated (nearly flat in Hexanchorus ); discal area partially to fully interrupted by prescutellar indentation in middle (medial impression only superficial in Hexanchorus ); transverse impression shifted more to the middle (anterior third in Hexanchorus ); (ii) mesotibiae without pubescence (e.g., Figs 3c-e ) on lateral sides, without tubercle on inner apex (lateral pubescence is present in all Hexanchorus species, all males have tubercle on inner apex); (iii) abdomen (Fig. 8 ) with fifth ventrite apically rounded, ventrites convex (in Hexanchorus fifth ventrite is apically emarginate in both sexes, male has ventrites impressed, female convex); (iv) male genitalia (Fig. 10f ) with fibula major and minor (only major in Hexanchorus ), some species with dorsal fibula (rod-like sclerite unknown in Hexanchorus ); (v) antennae (Figs 5a-e ) more compact, almost club-like (more loosely connected in Hexanchorus ; Figs 5f-t ), and (vi) mandibula (Fig. 4b ) with apical teeth fused (as opposed to three apical teeth present in Hexanchorus ; Fig. 4a ). Remark. Three Rumilara gen. nov. species ( R. obscura sp. nov. , R. riberai sp. nov. , R. suppressa sp. nov. ) differ from R. paterna sp. nov. and R. leleupi comb. nov. by femoral pubescence, which is restricted to long, dark, densely set, hair-like setae along dorsal margin, and by pro- and metatibial pubescence that is in a form of fringe at tibial apex. Included species. Rumilara leleupi comb. nov. , R. obscura sp. nov. , R. paterna sp. nov. , R. riberai sp. nov. , R. suppressa sp. nov.