Pilielmis shepardi, Polizei & Barclay, 2019

Polizei, Thiago T. S. & Barclay, Maxwell V. L., 2019, First records of the genera Neocylloepus and Pilielmis (Coleoptera: Elmidae Elminae) from Venezuela, with the description of Pilielmis shepardi sp. nov., Zootaxa 4688 (2), pp. 282-288 : 284-287

Pilielmis shepardi sp. nov.

( Figs 3-10 )

urn:lsid:zoobank.org:act:90DCFE7C-4089-4A52-A0B6-67BB24E334E2

Type locality. Icabarú , Bolivar State, Venezuela.

Type material. Holotype, male, with label data: VENEZUELA: Bolivar / nr. Icabarú, ahia lm SW / Sta. Elena de Uairen / 04 JULY 1987, 490m / at light, M.A.Ivie (MIZA).

Paratypes: 34 specimens, same data as holotype (6 to be deposited in MIZA, 6 in MZSP, 6 in BMNH, 6 in MAIC, 10 in USNM); (MZSP 31140-31142; 42273-42275) .

Diagnosis. Body subparallel. Head surface covered with micropunctures; antennomeres uniformly coloured. Pronotum moderately wider than long, with a deep and broad longitudinal impression on disc. Elytra 1.5 times longer than wide, one sublateral carina on interval VI, extending 3/4 of elytral length; apex and humeral angle yellowish in colour. Epipleura covered by tomentum. Hypomerum with a belt of tomentum reaching anterior and lateral margins. Disc of the first abdominal ventrite without tomentum. Aedeagus with the phallobase approximately as long as wide; parameres reaching ¾ of penis length; penis 1.5x the length of phallobase, ca 3.6x as long as wide, lateral margin subpararell, lateral margin near the apex with sensorial pores, apex sharp.

Description. Male: General colour light brownish, elytral apex and humeral angles yellowish. Total length 2.1 mm, greatest width 1 mm.

Head: Head capsule partially retractable; without impressions; surface with micropunctures separated from each other by their diameter, each with one seta. Eyes black; laterally protruding ( Figs. 3-5 ). Antennae filiform with 11 antennomeres; uniformly coloured. Clypeus broad and concave; 4x as wide as long; surface punctured. Frontoclypeal suture straight. Labrum ( Fig. 6 ) with lateral margins rounded; surface without setae, excepted by short row of spines on disc near the anterior margin, and antero-lateral margin with long setae. Mandible ( Fig. 7 ) with lateral lobe strongly pronounced; three apical teeth moderately sharp; prostheca feebly sclerotized with four bilobed lobes; lateral margin with short setae. Maxilla ( Fig. 8 ) with cardo subtriangular; stipes large, palpifer elongate; palpi with four palpomeres, without setae; galea palpiform and 2-articulated, with long thin setae at apex and five long setae laterointernally; lacinia subrectangular, 2x as long as wide, with three tufts of very thin and long setae anteriorly and long, thin setae anteriorly and externally. Labium ( Fig. 9 ) with mentum subrectangular; lateral margins feebly sinuous, with four long setae on each side, anterolateral angles sharp; palpiger present; palpi with three palpomeres, palpomeres 1 and 2 transverse; apical palpomere larger than basal two combined, with sensorial pores and two short setae on lateral margin; ligula wider than long, anterior margin straight, anterior angles rounded and produced laterally with short spines, ventral surface with two transverse rows of spines on disc. Gena with tomentum.

Thorax: Pronotum moderately wider than long ( Fig. 3 ). Anterior margin and anterior angles moderately acute; lateral margins convex with granules; posterior angles acute; posterior margin smooth with two prescutellar fovea. Pronotal surface covered with golden setae on disc and, with micropunctures separated by their own diameter; posterior half alutaceous. Sublateral carinae complete and sinuous, reaching the anterior and posterior margin ( Figs 3, 5 ). Longitudinal impression on disc deep and broad. Elytra ( Figs. 3, 5 ) 1.5x longer than wide, anterior margin straight; lateral margin slightly arcuate and apex truncate; apex yellowish in colour. Median suture elevated. Humeral angle elevated yellowish in colour. One short subcarinal basal on interval IV and one sublateral carina on interval VI, extending 3/4 of elytral length; surface with puncture rows separated by double rows of setae on each interval. Scutellum cordiform. Epipleura covered with tomentum ( Figs. 4 and 5 ). Hind wings macropterous. Prosternum as long as wide, with lateral portion covered by tomentum ( Figs. 4 and 5 ). Hypomeron 3x as long as wide, with a belt of tomentum reaching the anterior and lateral margins ( Figs 4 and 5 ). Prosternal process as long as wide; posterior margin elevated; surface with micropunctures; apex truncate. Mesoventrite with slightly broad depression to receive prosternal process; surface similar to prosternum. Metaventrite broad; lateral part covered by tomentum, disc alutaceous, with a longitudinal line, surface with few short setae. Legs except the tarsi covered with tomentum. Coxae and trochanter rounded. Femora narrowed at distal margin, 4x as long as wide. Tibiae elongate and thin, approximately 6x as long as wide; a row of spines on distal half. Tarsus elongate, apical tarsomere longer than the basal four combined, with long setae on apex. Claws large, thin with a tooth near the base ( Fig. 5a ).

Abdomen: Five visible ventrites ( Fig. 4 ), with margins moderately arcuate; surface covered by tomentum and micropunctures. Ventrite I with disc lacking tomentum. Ventrite V with apex rounded.

Genitalia: Total length 0.37 mm, greatest width 0.13 mm ( Fig. 10 ). Phallobase as long as wide. Parameres reaching ¾ of penis length, wider at base than at apex, rounded apically. Penis 1.5x the length of phallobase, ca 3.6x, basolateral apophyses twice as long as wide; lateral margin moderately sinuous and concave, apically with sensorial pores, apex slightly sharp; fibula approximately the length of the penis; corona present.

Female: External morphology similar to male.

Etymology. The specific epithet shepardi is a tribute to Dr. William Shepard in honour of his many contributions to the study of the riffle beetles.

Comments. Pilielmis shepardi sp. nov. can be easily differentiated from all other congeners by the colour pattern and the morphology of the male genitalia. The new species resembles P. apama Hinton, 1971 in body shape and size, rounded trochanters and the first abdominal ventrite with the disc lacking tomentum, but can be differentiated because in P. apama the antennae have the two first antennomeres distinctly paler than the remainder, and the colour pattern of the body is dark brown to blackish. In the male genitalia, P. apama has the phallobase approximately the same length as the penis, and the penis is wider basally than apically with apex rounded. P. shepardi sp. nov. has the antennae uniformly coloured, the body pattern colour brownish to yellow. The phallobase is half of the penis length, and the penis has the lateral margin moderately sinuous and concave, and the apex slightly pointed.

Pilielmis is very similar to Hexacylloepus but can be easily differentiated by the presence of only one sublateral carina on the elytra, and the claws bearing a tooth near the base ( Fig. 5a ). Hexacylloepus has two sublateral carina on the elytra and claws lack a tooth. The type material of the new species was housed in USNM as Hexacylloepus . Pilielmis shepardi sp. nov. represents the first record of the genus Pilielmis for Venezuela. Until now this genus was recorded only from Brazil (North – Amazon region), Colombia and French Guiana.

Figures

FIGURES 3–5. Habitus Pilielmis shepardi sp. nov. male, holotype. (3) Dorsal view. (4) Ventral view. (5) Lateral view. (5a) Hind tarsi and claw. Scale bars = 0.5mm.

FIGURES 6–10. Pilielmis shepardi sp. nov. (6) Labrum, ventral view. (7) Right mandible, ventral view. (8) Left maxilla, dorsal view. (9) Labium, ventral view. (10) Male genitalia, ventral view. Scale bars = 0.1mm.