Hexanchorus rostratus, Linsky, Marek, Ciamporova-Zatovicova, Zuzana & Ciampor Jr, Fedor, 2019

Linsky, Marek, Ciamporova-Zatovicova, Zuzana & Ciampor Jr, Fedor, 2019, Four new species of Hexanchorus Sharp from Ecuador (Coleoptera, Elmidae) with DNA barcoding and notes on the distribution of the genus, ZooKeys 838, pp. 85-109 : 95

Hexanchorus rostratus sp. n. Figs 5, 22, 27, 28, 36

Material examined.

Holotype (PUCE) ♂: "Ecuador, MoronaSantiago prov., Limón env., Río Yungantza, 02°59 ’49.3” S, 78°29 ’18.9” W 1522m a.s.l., 27.8.2013, stream ca 3m wide, fast flowing, partly shaded, with boulders, stones, gravel, Čiampor & Čiamporová-Zaťovičová lgt.". Paratypes (PUCE): 2 ♂♂ with the same data as holotype.

Diagnosis.

Hexanchorus rostratus sp. n. can be distinguished from all species of the genus by combination of the following male characters: 1) bigger size (CL: 3.46 - 3.58 mm); 2) mesotibiae with medial pubescent area extremely short, only at base and lateral pubescent area short, reaching to 1/4 of tibia 3) mesotibiae with indistinct tubercle on inner apex; 4) metatibiae with indistinct tubercle on inner apex; 5) elytra with slightly acute, almost rounded apices; 6) fifth ventrite moderately deeply but narrowly emarginate; 7) aedeagus with beak-like apical portion in lateral view.

Description.

Male. Body elongate, subparallel, dorsum moderately convex (Fig. 5). Length (CL) 3.46 - 3.58 mm; greatest width (EW) 1.25 - 1.32 mm, dorsal side brown with greenish iridescence; venter brown to almost black, tarsal claws reddish-brown. Dorsal surface densely covered with short recumbent setae and sparser, longer, dark, semi-erect setae; ventral surface densely covered with longer, golden, recumbent setae, especially on trochanters.

Head partly retractable into prothorax. Clypeus with anterior margin straight, about three times wider than long, shorter and narrower than labrum. Labrum feebly emarginate anteromedially, expanded laterally with sides broadly rounded, densely setose. Frontoclypeal suture visible, almost straight. Eyes suboval in lateral view, protruding from head outline, bordered by long black curved setae ( “eyelashes”) that arise near dorsal and ventral sides of eyes and extend toward middle of eye. Antenna moniliform, 11-segmented, pubescent; first two segments with dense long, dark brown setae, rest of antenna with only few such setae on sides; scape curved, about twice as long as pedicel, remaining segments about three times longer than first and second combined; segments 3-10 short, subtriangular; terminal segment subglobular with slightly pointed apex.

Pronotum (PL) 0.77 - 0.85 mm long, widest (PW: 0.96 - 1.03 mm) at base; with complete transversal depression at apical third and small basolateral impressions, with two prescutelar foveae; sublateral carinae absent; lateral margins convex before and after depression, basal angles slightly projected outwards; disc raised with concave sides near base; two tiny depressed dots medially near base; middle portion of base produced posteriorly; basal margin straight on sides, broadly rounded before scutellum. Scutellum subtriangular. Hypomeron narrow, straight. Prosternum extremely short in front of procoxae; prosternal process parallel-sided, apical portion subtriangular. Mesoventrite short with a deep, broad, V-shaped depression for reception of prosternal process. Metaventrite long and wide, slightly depressed along midline; discrimen thin and long, reaching abdomen. Legs slender,long. Procoxae and mesocoxae rounded, metacoxae transverse. Forelegs shortest, with all segments slightly wider than remaining pairs. Mesotibiae with medial pubescent area extremely short, only at base and lateral pubescent area short, reaching to 1/4 of tibia. Mesotibiae and metatibiae with indistinct tubercle on inner apex. Tarsi simple, fourth tarsal segment with fine, nearly erect setae ventrally, fifth segment longest. Tarsal claws long and stout.

Elytra (EL) 2.69 - 2.73 mm long, widest (EW: 1.25 - 1.32 mm) across humeri; with ten rows of small punctures forming striae; punctures separated by a distance three to four times the puncture diameter; humeral area slightly swollen. First four or five striae distinct, in nearly straight lines, remaining ones feebly visible, obscured apically. Epipleuron thin, widest in anterior third. Apical margin of elytra acutely produced.

Abdomen with five clearly visible ventrites (Fig. 22). Intercoxal process subtriangular with rounded apex. First three ventrites depressed medially; fifth ventrite moderately deeply but narrowly emarginate. Cuticle densely covered with short, golden, recumbent setae. Aedeagus (Figs 27, 28). elongate. Penis in ventral subparallel with distinct apophyses, narrowest in middle, with rounded apex, in lateral with subglobular apex skewed from below, strongly constricted then widened in basal half; with corona membranous, fibula not visible, straight oblong sclerotized structure present in apical half. Parameres about half as long as penis, in lateral view widest in basal half, tapering towards rounded apex, in ventral view with thin rounded apex, distinctly widening in apical half; Phallobase long, parallel-sided, curved in lateral view. Penis and parameres with sparse fine spines.

Female. Unknown.

Variation. We observed variation in size and pubescence, especially on abdominal sterna. Scale of green iridescence differed substantially.

Etymology.

Latin, rostrātus (beak-shaped), in reference to the apical part of penis in lateral view that resembles an upper beak of some birds.

Distribution.

Known only from the one locality in Morona-Santiago Province (Fig. 36).