Hexacylloepus shorti, 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 : 33-35

Hexacylloepus shorti sp. nov.

( Fig. 13 A–C)

Type locality: Venezuela, Amazonas State .

Diagnosis: Antennae without setae. Frontoclypeal suture straight. Pronotum with short, wide and deep longitudinal impression on disc, reaching only the posterior margin. Elytra with two pairs of yellow maculae, one on humeri and other on the middle, near the apex of the sublateral carina VI, and with an elevated and curved carina on interval IV. Hypomera with a transverse belt of tomentum reaching the anterior and lateral margin. Epipleura with tomentum. Pro- and mesotibiae each with a row of spines on distal half; meso- and metatibiae each with a row of setae on distal half. Abdomen with the disc of the first ventrite without tomentum, and with a deep depression with a pair of carinae extending towards and reaching the metaventrite. Male genitalia elongated; phallobase moderately longer than wide; parameres articulated with the phallobase, reaching one quarter of the penis length; penis very elongated, broad, with the lateral margins nearly parallel and apex rounded.

Description: Male. Body elongated, subparallel. Black colour, antenna, mouthparts and legs reddish-brown and yellow macula on elytra. Total length: 1.87 mm. Greatest width: 0.86 mm.

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

Thorax: Pronotum moderately longer than wide, arcuate anteriorly; sides strongly sinuate and slightly serrate, posterior margin smooth with two prescutellar foveae ( Fig. 13A ). Surface with micropunctures separated from each other by their diameter and with many setae. Sublateral carinae complete, sinuous and raised ( Fig. 13A ). Longitudinal impression short, wide and deep on disc, reaching only the posterior margin.

Elytra twice as long as wide; anterior margin arcuate, lateral margin moderately arcuate; rounded apex ( Fig. 13A ). Humeri rounded and prominent. Surface with puncture rows separated from each other by their diameter. Elytral suture moderately elevated. Elytra with two pairs of yellow macula, one on humeri and the other on the middle, near the apex of the sublateral carina VI. Carina short, elevated and curved 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 with tomentum ( Fig. 13B ). Hind wings macropterous. Scutellum shield-like.

Prosternum narrow, elevated, with a transverse carina on disc; anterior margin straight and lateral margin covered with tomentum. Prosternal process long, and beyond the procoxae; lateral margin elevated; rounded apex; disc moderately deep. Notosternal suture sinuous. Hypomera wider posteriorly than anteriorly; surface with micropunctures and with a transverse belt of tomentum reaching the anterior and lateral margins ( Fig. 13B ).

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

Legs (except tarsi) covered with punctures and tomentum ( Fig. 13B ). Coxae rounded; trochanter elongated; femora 6x as long as wide, 1/3 of the length of the elytra; tibiae thin, 8x as long as wide, 1/3 of the length of the elytra. Pro- and mesotibiae each with a row of spines on distal half. Meso- and metatibiae each with a row of setae on distal half. Tarsi elongate, with setae; apical tarsomere longer than the basal four combined. Claws long and thin.

Abdomen ( Fig. 13B ): 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 the apex rounded and with long setae.

Male genitalia ( Fig. 13C ): (Total length: 0.57 mm. Greatest width: 0.11 mm), symmetrical and elongated. Phallobase moderately longer than wide, with half of the penis length. Parameres articulated with the phallobase and reaching 1/4 of the penis length; 2x wider on base than at apex; apex rounded. Penis very elongated, with the lateral margin straight and apex rounded; fibula elongated with the penis length, moderately constricted at base.

Female: External morphology similar to male.

Material examined: 55 specimens.

Distribution: Venezuela, Brazil (Amazonas State) and Guyana.

Male holotype: Holo- type | ♂ | VENEZUELA, T.F. Amaz. / Cerro de la Neblina / 1 km SE Basecamp / 0º 50’N, 66º 10’W / 140m., 21 Feb. 1985 | Seined from rocks & / leaf packs in rapids / of whitewater stream / P.J.Spangler. / R. Faitoute, W. Steiner | Hexacylloepus / spp. / det. C. A. Maier 2012 (USNM)

Paratypes: 54 specimens: VENEZUELA, T.F. Amaz. / Cerro de la Neblina / 1 km SE Basecamp / 0º 50’N, 66º 10’W / 140m., 21 Feb. 1985 | Seined from rocks & / leafs packs in rapids / of whitewater stream / P.J.Spangler. / R. Faitoute, W. Steiner | Hexacylloepus / spp. / det. C. A. Maier 2012 (12 USNM; 4 MZSP; 4 NHMUK; 4 SEMK). GUYANA: Mazaruni- / Potaro District / Takutu Mountains / 6º15’N, 59º5’W / 12 December 1983 | Collected by / P.J.Spangler / R.A. Faitoute | HEXACYLLOEPUS / det. P.A.Spangler (5 USNM; 1 MZSP; 1 NHMUK; 1 SEMK) (MZSP 42077-42081). BRASIL. Amazonas. Presidente / Figueiredo. AM 240— Km 13. / Sítio do Maroca. 23.IV.2008. / 02°00’54,4”S 59º51’34,4”W 106m / Neusa Hamada et al. leg (6 INPA). BRASIL. Amazonas. Presidente / Figueiredo. AM 240— Km 58. / Igarapé Pedra Furada. 22.IV.2008. / 116m. 01°59’26,4”S 59º33’18,7”W / Neusa Hamada et al. leg (5 INPA). BRASIL. Amazonas. Presidente / Figueiredo. AM 240 Sítio dos / Pioneiros. 19.IV. 2008. 94m. / 02°04’05,0”S 59º54’28,8”W / Neusa Hamada et al. leg (11 MZSP) (MZSP 31542-31552).

Etymology: shorti is a tribute to Dr. Andrew Short (SEMK) in recognition of his studies of aquatic beetles.

Comparative notes: Hexacylloepus shorti sp. nov. can be differentiated from all the other species by the colour pattern and the curved elytral carina on the IV interval. These characters allow easy identification of the species.

Figures

FIGURE 13. Hexacylloepus shorti 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.