Pharceonus grandis, Maier, Crystal A., 2013

Maier, Crystal A., 2013, A revision of the Larainae (Coleoptera, Elmidae) of Venezuela, with description of nine new species, ZooKeys 329, pp. 33-91 : 77-80

Pharceonus grandis sp. n. Figs 5, 81, 82, 83, 84

Type material.

Holotype Male."Venezuela: Mérida State; 8°38.006'N, 71°09.782'W, 2037m; Monte Zerpa area; 20.vii.2009; leg. W. Shepard; stream margin; VZ09-0720-01Z" Holotype deposited in MIZA. Paratypes (20): VENEZUELA: Mérida State: Same data as Holotype (14 specimens SEMC). "Venezuela: Mérida State; 8°38.006'N, 71°09.782'W, 2037m; Monte Zerpa area; 20.vii.2009; leg. Short, Sites, Gustafson, &; Camacho; stream margin/pools; VZ09-0720-01A/L-1098" (1 specimen SEMC). "VENEZUELA: Mérida State; 8°35.355'N, 71°13.926' W 1646m; N. of Ejido, Rt. 4 river x-ing; 10.vii.2009; leg. Shepard; gross sample; VZ09-0720-02Z" (4 specimens SEMC). "VENEZUELA: Mérida State; 8°48.725'N, 70°47.057'W, 3012m; ca. 6 km E. Laguna Mucubaji; by Hotel Los Frailes; 19.vii.2009; W. Shepard; VZ09-0719-03Z; gross sample" (1 specimen SEMC). Paratypes will be deposited in: 2 in MIZA, 2 in MALUZ, 2 in USNM, 14 in SEMC.

Diagnosis.

This species can be distinguished from all other species of Pharceonus by its large size (3.5-4.3 mm), slightly reddish color (Fig. 81), wide genitalia (aedeagus + phallobase) (3.7x as long as wide) (Fig. 84), and pronotum with a deep and strongly bisinuate transverse impression across apical third (Fig. 83).

Description.

Holotype male. Body elongate, sub-parallel, moderately convex. Total length 3.7 mm, greatest width 1.6 mm. Cuticle dark reddish-brown, base of maxillary palpus, six basal antennomeres, femora, and tarsi lighter reddish-brown (Fig. 82). Dorsal surface with dense, erect brownish hair-like setae and denser and finer, golden, recumbent setae. Surface microreticulate, with dense fine punctures.

Head moderately coarsely, densely punctate; punctures separated by their diameter; cuticle microreticulate. Clypeus with anterior margin rounded. Fronto-clypeal suture deep and curved. Labrum with anterior margin entire and gently rounded; angle on each side obtuse, covered with setae approximately twice as long as setae on head. Eyes protruding only slightly laterally; separated by a distance about 3.5x the eye-width; bordered by long dark brown curved setae ( “eyelashes”) that arise near dorsal and ventral sides of eyes and extend toward middle of eye, setae not as prominent as in other genera. Antenna eleven segmented, pubescent, slightly clubbed; basal two antennomeres with long, brown, hair-like setae, thicker in width than proceeding antennomeres, with dense recumbent setae and dense brushy light brown setae. Antennal club of six antennomeres, compact, thickened towards apex (Fig. 81). Antennae short, reaching transverse groove of pronotum (Fig. 81). Apical five antennomeres dark brownish black, with dense recumbent setae. Apical antennomere rounded.

Pronotum heavily sculptured, as wide as long (0.9 mm and 0.9 mm, respectively); widest at basal third; anterior width two thirds the posterior width; anterior margin strongly convex over base of head; base tri-sinuate (Fig. 83). Pronotum with a sublateral depression on each side extending from a deep anterolateral fovea near the anterior margin towards the base, where it is joined to sub-basal, transverse and bisinuate depression; a short medial longitudinal and superficial groove joins the sub-basal and transverse depression with a strong tranverse and bisinuate depression at apical third; surface similarly punctate to head. Pronotal base with strong median gibbosity anterior to scutellum (Fig. 83). Hypomeron oblique. Scutellum slightly convex, broader than long, elevated posteriorly; posterior angle square. Prosternum long in front of procoxae; with tuft of long, golden setae apicomedially. Anterior margin reflexed ventrally. Prosternal process narrowly triangular, broad at base and tapering to apex; disc slightly impressed, lateral margins reflexed; middle convex; apex acuminate (Fig. 82). Mesoventrite short, depressed, with a deep, narrow, V-shaped depression for reception of apex of prosternal process. Metaventrite with disc inflated on posterior three-fourths, finely punctate behind mesocoxae; with deep, impressed longitudinal groove on midline of disc, groove deepest and broadest on posterior third of disc; with short, dense pubescence; cuticular surface of metaventrite finely microreticulate (Fig. 82).

Elytra more than three times as long as pronotum; lateral margins slightly sinuate; humeri and base adjacent to scutellum strongly gibbous; lateral margins smooth; apex rounded. Each elytron with ten coarse striae formed by a row of large punctures well separated by more than three times their diameter; striae slightly impressed becoming narrower and more shallow towards the apex; strial punctures coarse basally, becoming progressively finer towards apex; striae 3 and 4 converging sub-apically; intervals flat (Fig. 81). Elytral surface with dense, golden pubescence.

Legs thin and short (Fig. 81). Pro-, meso- and metatibiae with very short fringe of tomentum extending from about mid-tibia to nearly the tip. Surface of legs entirely pubescent, including mesotibiae. Mesotibia with small glabrous patch basally. Apical tarsomere of all legs with glabrous patch dorsally.

Abdomen with five ventrites. First ventrite distinctly carinate adjacent to metacoxae; carinae extending longitudinally behind metacoxae for almost entire length of first ventrite; cuticle densely covered with short, recumbent setae (Fig. 82). Ventrite IV with median V-shaped carina; carina covered with thicker setae than rest of ventrite (Fig. 82). Last ventrite subtruncate, covered with dense, long, dark brown setae. Genitalia (aedeagus + phallobase wide, 3.7 × as long as wide, gently curved (Fig. 84).

Female. Externally similar to male except slightly larger in size, elytral gibbosities more producted, and elytral sutural stria slightly inflated in apical third (Fig. 81). Protibiae slightly less curved than those of male. Metaventral disc not as deeply and less concave. Abdominal ventrite 4 lacking median V-shaped carina. Apical abdominal ventrite with less dense setae than male.

Intraspecific variation.

This species varies slightly in color, from dark reddish-brown to medium reddish-brown, length (3.5-4.2 mm), and degree of setation.

Distribution and habitat.

Pharceonus grandis has been collected only in the Mérida Andes in Venezuela (Fig. 5), at stream margins and in bulk benthic samples.

Etymology.

Pharceonus grandis is named after the Latin “grandis”, meaning large, referring to its large size.

Associated species.

No other laraine species were collected with Pharceonus grandis .The following aquatic beetle taxa were collected at the same localities as Pharceonus grandis : Andogyrus spp. ( Gyrinidae ), Andonectes spp. ( Dytiscidae ), Enochrus spp. ( Hydrophilidae ), Hydraena spp. ( Hydraenidae ).