Hexacylloepus metapa, 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 : 29-31

Hexacylloepus metapa sp. nov.

( Fig. 11 A–C)

Type locality: Guatemala, Escuintla Department.

Diagnosis: Antennae without setae. Frontoclypeal suture inconspicuous. Pronotum with a long, wide and deep longitudinal impression on disc, reaching the anterior and posterior margins. Hypomera with a transverse belt of tomentum reaching only the lateral margin. Epipleura without tomentum. Tibiae each with two rows of setae in distal half. Abdomen with the disc of the first ventrite without tomentum, and a deep depression with a pair of carinae extending towards and reaching the metaventrite; anterior half of the second ventrite without tomentum. Male genitalia acute; phallobase slightly longer than wide, 1/3 of the penis length, parameres reaching 1/4 of the penis length; penis very thin and elongated, constricted in anterior 2/4, with the lateral margin straight; apex strongly pointed.

Description: Male. Body elongated, subparallel. Black colour, with the antenna, mouthparts and legs reddishbrown. Total length: 1.72 mm. Greatest width: 0.82 mm.

Head: surface with micropunctures separated from each other by their diameter. Antenna inserted on the anterior margin of the eyes, filiform, with 11 antennomeres, each one with long thin setae at apex. Frontoclypeal suture inconspicuous. Clypeus 3x as wide as long; anterior margin arcuate and posterior sinuous; surface similar to that of head. Labrum twice as wide as long; antero-lateral angles rounded and alutaceous; surface with micropunctures. 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 long as wide, arcuate anteriorly; sides sinuate and serrate, posterior margin smooth with two prescutellar foveae ( Fig. 11A ). Surface with micropunctures. Sublateral carinae complete, strongly sinuous and raised ( Fig. 11A ). Longitudinal impression long, wide and deep on disc, reaching the anterior and posterior margins and wider on middle portion ( Fig. 11A ).

Elytra moderately longer than wide; anterior margin arcuate, lateral margin arcuate and serrate; rounded apex ( Fig. 11A ). Humeri rounded and prominent. Surface with puncture and setae. Elytral suture elevated. Carina short and elevated on interval IV, extending from base to 1/4 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. 11B ). Hind wings macropterous. Scutellum oval.

Prosternum narrow, surface with micropunctures; anterior margin straight and lateral margin covered with tomentum. Transverse depression on disc. Prosternal process long, and beyond the procoxae; lateral margin elevated; rounded apex. Notosternal suture sinuous. Hypomera wider posteriorly than anteriorly, lateral margin serrate; surface with micropunctures and with a transverse belt of tomentum reaching only the lateral margin ( Fig. 11B ).

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

Legs (except tarsi) covered with punctures and tomentum ( Fig. 11B ). Coxae rounded; trochanter elongated; femora very robust 2,5x longer than wide, with 1/4 of the elytra length; tibiae thin, 4x as long as wide, with 1/4 of the elytra length, each with a row of long setae on 2/3 of distal half (especially on metatibiae). Meso- and metatibiae each with a row of spines on distal 2/3. Tarsi elongate, with apical tarsomere longer than the basal four combined. Claws long and thin.

Abdomen ( Fig. 11B ): 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 and anterior half of the second). Fifth ventrite with lateral margins slightly produced posterolaterad, with apex tapered with groove and with long setae.

Male genitalia ( Fig. 11C ): (Total length: 0.83 mm. Greatest width: 0.18 mm), symmetrical and very elongated. Phallobase moderately longer than wide, with 1/3 of the penis length. Parameres fused and articulated with the phallobase; reaching 1/4 of the penis length, 4x wider on base as at the apex; apex moderately sharp. Penis very thin and elongated; constricted at second quarter anteriorly, with the lateral margin straight; apex strongly sharp, ten times as long as wide; fibula elongated and thin, with approximately the penis length.

Female: External morphology similar to male, except for the absence of the row of spines on meso- and metatibiae, and for the lack of a depression on the disc of the first abdominal ventrite.

Material examined: 23 specimens.

Distribution: Guatemala: Escuintla Department.

Male holotype: ♂ | Rio Metapa / iii.70 Guat. / H. B. N. Hynes | H.E. Hinton / collection. / B.M.1977-566 . | Holo- / type ( NHMUK)

Paratypes: 22 specimens Rio Metapa / iii.70 Guat. / H. B. N. Hynes | H.E.Hinton / collection. / B.M.1977-566. (9 ♂ 3 ♀ NHMUK; 3 ♂ 2 ♀ MZSP; 3 ♂ 2 ♀ USNM) (MZSP 35755-35759) .

Etymology: metapa is a reference to the river where the species was collected.

Comparative notes: Hexacylloepus metapa sp. nov. resembles H.manauara sp. nov. in body shape and in the short longitudinal impression on the pronotum. However, in H. metapa sp. nov. there is no tomentum on the epipleura, unlike H. manaura sp. nov. The male genitalia also are different: in H. metapa sp. nov. the penis is very thin and elongated, constricted on anterior half; in H. manaura sp. nov. the penis is very elongated, constricted at the base, with the lateral margin straight.

Figures

FIGURE 11. Hexacylloepus metapa 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.