Hexanchorus shepardi, 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 : 98-102

Hexanchorus shepardi sp. n. Figs 10, 11, 20, 21, 29, 30, 36

Material examined.

Holotype (PUCE) ♂: "Ecuador, Napo prov., road to Coca, Sumaco env., 00°42 ’25.7” S, 77°43 ’10.0” W 1138m a.s.l., 17.8.2013, stream ca 2-3 m wide, fast flowing, with boulders, stones, gravel, submerged wood, Čiampor & Čiamporová-Zaťovičová lgt." Paratypes (PUCE, NMW, CCB): 1 ♂, 5 ♀♀ with the same data as holotype.

Diagnosis.

Hexanchorus shepardi sp. n. can be distinguished from all species of the genus by combination of the following male characters: 1) moderate size (CL: 3.22 - 3.36 mm); 2) mesotibiae with medial pubescent area long, extending before apex and lateral pubescent area shorter reaching behind first third; 3) mesotibiae with small tubercle on inner apex; 4) metatibiae with indistinct tubercle on inner apex; 5) elytra with slightly acute, almost rounded apices; 6) fifth ventrite deeply and broadly emarginate; 7) aedeagus with ovate apical portion in ventral view.

Description.

Male. Body elongate, subparallel, dorsum moderately convex (Fig. 10). Length (CL) 3.22 - 3.36 mm; greatest width (EW) 1.31 - 1.37 mm, dorsal side dark 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 emarginated 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) 0.83 - 0.87 mm long, widest (PW: 1.07 - 1.08 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 long, extending before apex and lateral pubescent area shorter reaching behind first third. Mesotibiae with small tubercle on inner apex, 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) 2.42 - 2.63 mm long, widest (EW: 1.31 - 1.37 mm) across humeri; subparallel in anterior 4/5, 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. 20). Intercoxal process subtriangular with rounded apex. First three ventrites depressed medially; fifth ventrite deeply and broadly emarginate. Cuticle densely covered with short, golden, recumbent setae. Aedeagus (Figs 29, 30) elongate. Penis in ventral view subparallel with short apophyses, apical part ovate with rounded apex, in lateral view slender, sinuate, with widened basal third, with corona membranous, fibula not visible, curved oblong sclerotized structure present in middle. Parameres about 1.7x shorter than penis, in lateral view widest at base, moderately tapering towards rounded apex, in ventral view jointed in middle, with rounded apex. Phallobase parallel-sided, in later view curved and slender. Penis and parameres with sparse fine spines.

Female. Externally similar to male (Figs 11, 21) except bigger (CL: 3.58 - 3.62 mm); meso - and metatibiae without carina on inner apex; first three ventrites medially convex and fifth ventrite very broadly but shallowly emarginate. Females vary only slightly in size (PL: 0.77 - 0.78 mm, PW: 1.00 - 1.01 mm, EL: 2.81 - 2.84 mm, EW: 1.24 - 1.27 mm).

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

Etymology.

The species is named after Prof. William D. Shepard, great American coleopterologist and expert on dryopoid beetles.

Distribution.

Known only from the one locality in Napo Province (Fig. 36).