Hexacylloepus zaninii, 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 : 44-45

Hexacylloepus zaninii sp. nov.

( Fig. 18 A–C)

Type locality: Brazil, São Paulo State, Assis .

Diagnosis: Antennae without setae. Frontoclypeal suture inconspicuous. Pronotum with a short, wide and deep longitudinal impression on disc, not reaching the anterior and posterior margins. Hypomera with a belt of tomentum reaching the lateral and anterior margin. Epipleura with tomentum. Metatibiae each with a row of spines on distal half. Abdomen with the disc of the first ventrite without tomentum. Male genitalia with the phallobase twice as long as wide; parameres reaching 1/3 of the penis length; apex slightly rounded with the antero-lateral angles produced posterolaterad; penis with the lateral margin sinuous and apex arrowhead-like.

Description: Male. Body subparallel. Reddish-brown colour, with the antenna, mouthparts and legs light reddish-brown. Total length: 1.57 mm. Greatest width: 0.77 mm.

Head: surface with micropunctures and many setae. Antenna inserted on the anterior margin of the eyes, filiform, with 11 antennomeres without setae. Frontoclypeal suture inconspicuous. Clypeus 3x as wide as long; anterior margin straight and posterior margin sinuous; surface similar to that of head. Labrum twice as wide as long; anterolateral angles rounded and alutaceous; surface without setae. Maxillary palpus 4-segmented; terminal palpomere truncated apically. Labial palpus 3-segmented. Mentum and submentum squared. Gula rectangular. Genae covered with tomentum.

Thorax: Pronotum longer than wide, arcuate anteriorly; sides sinuate and slightly serrate, posterior margin smooth and with two prescutellar foveae ( Fig. 18A ). Surface with micropunctures and short setae. Sublateral carinae complete and sinuous. Longitudinal impression short, wide and deep on disc and not reaching the anterior and posterior margin ( Fig. 18A ).

Elytra moderately longer than wide; anterior margin arcuate, lateral margin strongly arcuate; rounded apex ( Fig. 18A ). Humeri flat. Surface with puncture rows separated from each other by their diameter and many short setae. Elytral suture moderately prominent. 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 2/3 on VI elytral and 1/4 on VIII interval. Epipleura with tomentum ( Fig. 18B ). Hind wings macropterous. Scutellum oval.

Prosternum wide and square; surface with micropunctures, anterior margin straight and sides covered with tomentum. Prosternal process squared, and beyond the procoxae; lateral margin flat; apex squared; disc shallow. Notosternal suture slightly sinuous. Hypomera wider posteriorly than anteriorly, lateral margin serrate; surface with micropunctures and with a belt of tomentum reaching the anterior and lateral margin ( Fig. 18B ).

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

Legs (except tarsi) covered with punctures and tomentum ( Fig. 18B ). Coxae rounded; trochanter short; femora short, 3x as long as wide and 1/4 of the elytra length; tibiae thin, 6x as long as wide and 1/3 of the length of the elytra. Metatibiae each with a row of spines on distal half. Tarsi elongate, with setae; apical tarsomere with the length of the basal four combined. Claws long and thin.

Abdomen ( Fig. 18B ): 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). Disc of the first shallow. Fifth ventrite with the apex rounded.

Male genitalia ( Fig. 18C ): (Total length: 0.46 mm. Greatest width: 0.12 mm), symmetrical. Phallobase twice as long as wide, slightly longer than penis length. Parameres articulated with the phallobase, reaching 1/3 of the penis length; 3x as wide on base as at the apex; apex slightly rounded and with the antero-lateral angles produced posterolaterad. Penis with the lateral margin sinuous and apex moderately sharp; fibula elongated, approximately the same length as the penis; corona present and subdivided.

Female: External morphology similar to male, except for the absence of the row of spines on each metatibia.

Material examined: 26 specimens.

Male holotype: ♂ | Holo- / type | BR-SP-Assis / Horto Florestal / 26.V.2006 / P.C.Bispo leg. | MZSP36046 (MZSP).

Paratypes: 25 specimens: BR-SP-Assis / Horto Florestal / 26.V.2006 / P.C.Bispo leg. (2 MZSP; 3 NHMUK). BR-MS-Novo Mundo / Córrego Guaçu / 23°53’31.03”S, 54°18’41.33”W / 19.I.2014 / V.F.B.Silva leg. (10 MZSP; 5 NHMUK; 5 SEMK) (MZSP 36047-36059).

Distribution: Brazil: São Paulo and Mato Grosso do Sul States.

Etymology: zaninii is a tribute to Professor Dr. Ciro Cesar Zanini Branco in recognition of his studies of limnology.

Comparative notes: Hexacylloepus zaninii sp. nov. resembles H. manauara sp. nov. due to the similar body shape and, covering of setae, and inconspicuous frontoclypeal suture. They can be easily differentiated using the male genitalia and colour pattern. Hexacylloepus zaninii sp. nov. has the epipleura with tomentum, short legs, and belt of tomentum on hypomera reaching the anterior and posterior margin. These morphological characteristics differ from those of H. manauara sp. nov. which has the epipleura without tomentum, long legs, and belt of tomentum on hypomera reaching only the lateral margin. The male genitalia are also different: in H. zaninii sp. nov. the parameres have the apices slightly rounded and the antero-lateral angles produced posterolaterad, and the penis has the lateral margin sinuous and the apex moderately sharp; in H. manauara sp. nov. the parameres have the apices moderately sharp, and the penis is very elongated and the apex slightly pointed.

Figures

FIGURE 18. Hexacylloepus zaninii 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.