Hexacylloepus barrae, Polizei & Barclay & Bispo, 2020

Polizei, Thiago T. S., Barclay, Maxwell V. L. & Bispo, Pitágoras C., 2020, Hexacylloepus Hinton, 1940 rises again; 18 new species of a neglected genus (Coleoptera: Byrrhoidea: Elmidae), Zootaxa 4819 (1), pp. 6-48 : 7-9

Hexacylloepus barrae sp. nov.

( Fig. 1 A–C)

Type locality: French Guiana, St.-Laurent-du-Maroni.

Diagnosis: Antennae with thin setae at apex of each antennomere. Frontoclypeal suture inconspicuous. Pronotum with a long and narrow longitudinal impression on disc, reaching the anterior and posterior margins. Hypomera with a short belt of tomentum reaching only the portion near to notosternal suture. Epipleura without tomentum. Profemur with a row of setae on proximal two-thirds; protibiae each with a row of setae on distal two-thirds; meso- and metatibiae each with a row of setae occupying the distal half. Abdomen with the disc of the first ventrite without tomentum, and fifth ventrite with lateral margins slightly produced posterolaterad. Male genitalia elongated; phallobase 3x as long as wide; parameres reaching 3/4 of the penis length; penis with the lateral margin sinuous, slightly tapered toward the apex.

Description: Male. Body elongated, subparallel. Reddish-brown colour, with the dorsal surface covered with setae. Total length: 2.03 mm. Greatest width: 1.01 mm.

Head: surface with micropunctures separated from each other by their diameter. Antenna inserted on the anterior margin of the eye, filiform, with 11 antennomeres each one with long thin setae at apex. Frontoclypeal suture inconspicuous. Clypeus 3x as wide as long; anterior margin slightly arcuate and posterior sinuous; surface similar to that of head. Labrum twice as wide as long; antero-lateral angles rounded and alutaceous surface, covered with short and thin setae on anterior portion. Maxillary palpus 4-segmented; terminal palpomere truncated apically. Labial palpus 3-segmented. Mentum and submentum rectangular. Gula rectangular. Genae covered with tomentum.

Thorax: Pronotum as wide as long, arcuate anteriorly and laterally; posterior margin smooth with two prescutellar foveae ( Fig. 1A ). Surface with micropunctures separated from each other by their diameter and covered with many golden setae. Sublateral carinae complete, sinuous and raised ( Fig. 1A ). Longitudinal impression long and narrow on disc, reaching the anterior and posterior margins.

Elytra slightly longer than wide; anterior margin arcuate, lateral margin moderately straight; rounded apex ( Fig. 1A ). Humeri rounded and prominent. Surface with punctures and setae rows separated from each other by their diameter ( Fig. 1A ). Elytral suture elevated. Carina short and elevated on interval IV, extending from base to 1/3 of the elytral length; sublateral carinae on intervals VI and VIII, extending from base to 3/4 of the elytral length. Epipleura without tomentum ( Fig. 1B ). Hind wings macropterous. Scutellum oval.

Prosternum broad, surface covered with micropunctures, anterior margin straight and covered with setae and lateral margin covered with tomentum. Disc with a transverse depression. Prosternal process long and narrow, and beyond the procoxae; lateral margin elevated; rounded apex; disc strongly deep. Notosternal suture sinuous. Hypomera wider posteriorly than anteriorly, lateral margin serrate, surface with micropunctures and with a short belt of tomentum reaching only the portion near to notosternal suture ( Fig. 1B ).

Mesoventrite with a groove to receive the prosternal process. Mesepimeron and mesepisternum covered with tomentum. Metaventrite broad with the longitudinal medial depression; surface with micropunctures and with sides covered with tomentum.

Legs (except tarsi) covered with punctures and tomentum ( Fig. 1B ). Coxae rounded; trochanter elongated; femora 3x as long as wide, one-third of the length of the elytra; tibiae long and thin, 6x as long as wide, one-third of the length of the elytra. Profemora with a row of setae on proximal two-thirds portion. Protibiae each with a row of setae on two-thirds of the distal portion. Meso- and metatibiae each with a row of setae on distal half. Tarsi elongate, with setae; apical tarsomere with the length of the basal four combined. Claws long and thin.

Abdomen ( Fig. 1B ): five ventrites; as long as wide. Anterior and posterior margins straight on the first and second ventrites and arcuate on the subsequent ventrites, lateral margins rounded. Surface densely covered with tomentum (excepted for disc of first ventrite), micropunctures and short setae. Disc of the first ventrite, with a pair of carinae extending towards and reaching the metaventrite. Fifth ventrite with lateral margins slightly produced posterolaterad, with the apex rounded and with short setae.

Male genitalia ( Fig. 1C ): (Total length: 0.72 mm. Greatest width: 0.17 mm), symmetrical and elongated. Phallobase 3x as long as wide, longer than penis length. Parameres articulated with the phallobase, reaching 3/4 of the penis’s length; 2x wider at base as at the apex; apex moderately sharp, with a tuft of long and thick setae. Penis with the lateral margin sinuous; slightly tapered toward the apex; 4x as long as wide; fibula elongated, wide, approximately the same length as the penis, corona present, arrangement of tiny rod-like sclerotizations.

Female: External morphology similar to male.

Material examined: 11 specimens.

Distribution: French Guiana: St.-Laurent-du-Maroni.

Male holotype: ♂ | F. GUIANA. / St. Laurent. / ix.1937 / H.E.Hinton | H.E.Hinton / collection. / B.M.1977-566. | Holo- / type (NHMUK)

Paratypes: 10 specimens: F. GUIANA. / St. Laurent. / ix.1937 / H.E.Hinton | H.E.Hinton / collection. / B.M.1977-566. | Para- / type (2 ♂ 2 ♀ NHMUK; 2 ♂ 1 ♀ MZSP; 2 ♂ 1 ♀ USNM) (MZSP 35752-35754) .

Etymology: barrae is a tribute to Cheryl Barr, specialist on aquatic Byrrhoidea.

Comparative notes: Hexacylloepus barrae sp. nov. resembles Hexacylloepus plaumanni ( Hinton, 1937) with a belt of tomentum on hypomera, pronotum with a long and narrow longitudinal impression, and meso- and metatibiae each with a row of setae on the distal half portion. However, H. barrae sp. nov., can be distinguished by the pronotum longer than wide while H. plaumanni has the pronotum as long as wide. In H. barrae sp. nov. the parameres are articulated with the phallobase, reaching 3/4 of the penis length; penis with the lateral margin sinuous; slightly tapered toward the apex; 4x as long as wide. In H. plaumanni , the parameres are wide and long, reaching 2/3 of the penis length; penis with the lateral margin straight; moderately constricted at base.

Figures

FIGURE 1. Hexacylloepus barrae sp. nov.. Male. Holotype. (A–B) Habitus. (A) Dorsal view. (B) Ventral view. (C) Ventral view of male genitalia. Scale bars: (A–B) = 0.5mm. (C) = 0.1mm.