Hexacylloepus taylorae, 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 : 36-38

Hexacylloepus taylorae sp. nov.

( Fig. 14 A–C)

Type locality: Ecuador, Sucumbíos Province. Limoncocha .

Diagnosis: Antennae without setae. Frontoclypeal suture inconspicuous. Pronotum with a wide and deep longitudinal impression on disc, not reaching the anterior and posterior margins. Hypomera with a belt of tomentum reaching the anterior and lateral margins. Epipleura with the anterior half covered with tomentum. Tibiae each with row of setae on distal half; metatrochanter with a spur on the middle. Abdomen with the disc of the first ventrite without tomentum, and fifth ventrite with a groove with many at apex setae. Male genitalia with the phallobasis 2.5x longer than wide; parameres reaching 2/3 of the penis length; penis arrow-like, with a lateral tooth at the middle, lateral margin sinuous; apex strongly arrowhead-like, with antero-lateral angles strongly sharp.

Description: Male. Body elongated, subparallel. Black colour, with the antenna, mouthparts and legs light reddish-brown. Total length: 1.68 mm. Greatest width: 0.79 mm.

Head: surface with micropunctures. 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 concave and posterior sinuous; surface similar to that of head and with setae. Labrum twice as wide as long; antero-lateral angles rounded and alutaceous; surface with long 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 as long as wide, arcuate anteriorly; sides sinuate and serrate; posterior margin smooth with two prescutellar foveae ( Fig. 14A ). Surface with micropunctures separated from each other by their diameter and with golden setae. Sublateral carinae complete, sinuous and raised ( Fig. 14A ). Longitudinal impression wide and deep on disc, not reaching the anterior and posterior margins.

Elytra twice as long as wide; anterior margin arcuate, lateral margin moderately arcuate and serrate; raised apex ( Fig. 14A ). Humeri rounded and prominent. Surface with punctures and each interval covered by double setae rows. Elytral suture strongly 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 with the anterior half covered with tomentum ( Fig. 14B ). Hind wings macropterous. Scutellum oval.

Prosternal process long, and beyond the procoxae; lateral margin elevated; apex arrow-like; disc flat. Notosternal suture sinuous. Hypomera wider posteriorly than anteriorly, lateral margin serrate; surface with micropunctures and with a belt of tomentum reaching the lateral and anterior margins ( Fig. 14B ).

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

Legs (except tarsi) covered with punctures and tomentum ( Fig. 14B ). Coxae rounded; trochanter elongated; femora robust 3x as long as wide, 1/3 of the length of the elytra; tibiae long and thin, 5x longer than wide, 1/3 of the length of the elytra. Tibiae each with a row of setae in distal 2/3. Metatrochanter with a spur. Meso- and metatibiae each with groove on distal half with a row of short spines. Tarsi elongate, with setae; apical tarsomere with the length of the basal four combined. Claws long and thin.

Abdomen ( Fig. 14B ): 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. Fifth ventrite with lateral margins slightly produced posterolaterad, apex tapered, with many short setae and a groove.

Male genitalia ( Fig. 14C ): (Total length: 0.70 mm. Greatest width: 0.16 mm), symmetrical. Phallobase 2.5x longer than wide, and longer than penis. Parameres articulated with the phallobase, reaching 2/3 of the penis length; lateral margin sinuous with the apex sharp and with a row of spines on internal margin. Penis arrow-like with lateral margin sinuous; apex strongly arrow-like, with antero-lateral angles very sharp; fibula rhombus-like, approximately the same length as the penis.

Female: External morphology similar to male, except for the absence of a groove with a row of spines on meso- and metatibiae and the absence of a spur on metatrochanter.

Material examined: 26 specimens.

Male holotype: ♂ | ECUADOR, Napo [nowadays Sucumbíos] / Limoncocha / 14 June 1977 / P.J.Spangler & D.R.Givens#126 | ECUADOR—PEACE / CORPS—SMITHSONIAN / INSTITUTION AQUATIC / INSECT SURVEY | HEXACYLLOEPUS / det.P.J.Spangler (USNM)

Paratypes: 25 specimens (4 ♂ 22 ♀): ECUADOR, Napo [nowadays Sucumbíos] / Limoncocha / 14 June 1977 / P.J.Spangler & D.R.Givens #126 | ECUADOR—PEACE / CORPS—SMITHSONIAN / INSTITUTION AQUATIC / INSECT SURVEY | HEXACYLLOEPUS / det. P.J.Spangler (2 ♂ 14 ♀ USNM; 1 ♂ 4 ♀ NHMUK; 1 ♂ 4 ♀ MZSP) (MZSP 42082-42086) .

Distribution: Ecuador.

Etymology: taylorae is a tribute to Christine Taylor, curator of aquatic beetles at NHMUK.

Comparative notes: Hexacylloepus taylorae sp. nov. resembles H. abdominalis ( Hinton, 1937) , due to the similar colour pattern, similar longitudinal impression on pronotum and elytra interval covered by double setae rows. However, H. taylorae sp. nov. has a spur on metatrochanter, and no spur in the middle of the second abdominal ventrite. These morphological characteristics differ from those of H. abdominalis which has no spur on the metatrochanter but has a spur in the middle of the second abdominal ventrite. The male genitalia also are different: in H. taylorae sp. nov. the parameres extend 2/3 of the penis length, and the penis is arrow-like with the lateral margin sinuous, apex strongly pointed, and antero-lateral angles very sharp; in H. abdominalis , the parameres extend half of the penis length, and the penis is oval, slightly constricted at the base.

Figures

FIGURE 14. Hexacylloepus taylorae 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.