Hexacylloepus casariae, 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 : 11-13

Hexacylloepus casariae sp. nov.

( Fig. 3 A–C)

Type locality: Brazil, Minas Gerais State, Arinos .

Diagnosis: Antenna filiform without setae. Frontoclypeal suture inconspicuous. Pronotum with a long, deep and wide longitudinal impression, reaching the anterior and posterior margins. Elytra with a longitudinal reddish-brown stripe extending from intervals III to VIII in width. Hypomera with a complete, dense belt of tomentum. Epipleura with tomentum. Tibiae with distal portion wider than proximal; meso and metatibiae each with a depression on distal half and with a row of fan-like setae. Abdomen with all ventrites covered with tomentum. Male genitalia spatulate; phallobase twice as long as wide; parameres, reaching 3/4 of the penis length; penis spatulate with anterior half narrower than posterior half, apex rounded.

Description: Male. Body elongated, subparallel. Brown colour, with antenna, mouthparts, legs and stripe on elytra reddish-brown. Total length: 1.46 mm. Greatest width: 0.64 mm.

Head: s urface with micropunctures separated from each other by their diameter. Antenna inserted at the anterior margin of the eyes, filiform, with 11 antennomeres without setae. Frontoclypeal suture inconspicuous. Clypeus 4x as wide as long; anterior margin straight, posterior margin rounded; surface similar to that of head. Labrum twice as wide as long; antero-lateral angles rounded; surface with micropunctures and without setae. Maxillary palpus 4-segmented; terminal palpomere truncate apically. Labial palpus 3-segmented. Mentum and submentum wide and flat. Gula rectangular. Genae covered with tomentum.

Thorax: Pronotum slightly longer than wide, arcuate anteriorly; sides sinuate and serrate; posterior margin smooth with two prescutellar foveae ( Fig. 3A ). Surface with micropunctures and setae. Sublateral carinae complete, sinuous and raised. Longitudinal impression long, wide and deep on disc, reaching anterior and posterior margins ( Fig. 3A ).

Elytra twice as long as wide; anterior margin arcuate; lateral margin moderately arcuate and serrate; rounded at apex ( Fig. 3A ). Humeri rounded and prominent. Surface with puncture rows separated from each other by their diameter and with short setae. One longitudinal reddish-brown band extends into elytral intervals III to VIII ( Fig. 3A ). Elytral suture moderately elevated. Carina short and prominent 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. 3B ). Hind wings macropterous. Scutellum oval.

Prosternum broad with micropunctures; anterior margin straight and lateral margin with tomentum. Prosternal process longer than wide, beyond the procoxae; lateral margin slightly elevated; apex arcuate; disc broad. Notosternal suture slightly sinuous. Hypomera wider posteriorly than anteriorly, lateral margin serrate, surface with micropunctures, with a belt of tomentum reaching lateral and anterior margin ( Fig. 3B ).

Mesoventrite with a slight groove to receive the prosternal process. Mesepimeron and mesepisternum with tomentum. Metaventrite broad with a longitudinal medial depression; surface covered with micropunctures, short setae and with sides with tomentum ( Fig. 3B ).

Legs (except tarsi) covered with punctures and tomentum ( Fig. 3B ). Coxae rounded; trochanters elongated; femora 4x as long as wide, 1/3 of the length of the elytra; tibiae long and thin, 10x as long as wide, 1/3 of the length of the elytra. Meso- and metatibiae each with a deep groove in distal half and with a row of fan-like setae. Tarsi elongate, with setae; apical tarsomere longer than the basal four combined. Claws long and thin.

Abdomen ( Fig. 3B ): five ventrites; as long as wide. Anterior and posterior margin straight on the first and second ventrite and arcuate on the subsequent ventrites, lateral margins rounded. Surface densely covered with tomentum and micropunctures. Fifth ventrite with rounded apex and with long setae.

Male genitalia ( Fig. 3C ): (Total length: 0.39 mm. Greatest width: 0.12 mm.), symmetrical. Phallobase twice as long as wide, slightly longer than the penis length. Parameres fused and articulated with the phallobase, reaching 3/4 of the penis length; apex slightly acute. Penis spatulate with anterior half narrower than posterior half; apex rounded; fibula elongated, approximately the same length as the penis.

Female: Unknown

Material examined: 2 specimens.

Distribution: Brazil: Minas Gerais State.

Male holotype: ♂ | Holo- / type | BR-MG-Arinos / 6-8.XI.1964 / Expedição Departamento / de Zoologia—USP | MZSP 35707 (MZSP)

Paratype: ♂ | Para- / type | BR-MG-Arinos / 6-8.XI.1964 / Expedição Departamento / de Zoologia—USP. (NHMUK)

Etymology: casariae is a tribute to Dr. Sônia Casari, curator of the Coleoptera collection at MZSP.

Comparative notes: Hexacylloepus casariae sp. nov. is quite different from other known species of Hexacylloepus by its general external morphology and the male genitalia. It can easily be differentiated by this combination of characters: longitudinal reddish-brown stripe on elytra; abdominal ventrites covered with tomentum, antenna without setae and meso- and metatibiae each with a deep groove in distal half, and with a row of fan-like setae.

Figures

FIGURE 3. Hexacylloepus casariae 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.