Hexanchorus inflatus, 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 : 54-57

Hexanchorus inflatus sp. n. Figs 4, 43, 44, 45, 46, 47

Type material.

Holotype Male."Venezuela Exp[edition].; Territ. Amazonas; Upper Cunucunuma; Tapara Apr. 20, 1950" "J. Maldonado; Capriles Coll." Holotype deposited in USNM. Paratypes (5): VENEZUELA: Amazonas State: Same data as holotype (5 Specimens). Paratypes will be deposited in: 4 in USNM, 1 in SEMC.

Diagnosis.

This species can be distinguished from all other Hexanchorus species that occur in Venezuela by the following combination of characters: antennae long (Fig. 44), extending behind transverse impression of pronotum; pronotum lacking median longitudinal impression (Fig. 43); and protibia with deep excavation apically (Fig. 46). It most closely resembles Hexanchorus homaeotarsoides in distribution and that the female bears a median projection of the third ventrite, but can be distinguished from the former species by the distinctly inflated elytral apices (Fig. 45), and aedeagus with a smooth apex (Fig. 47).

Description.

Holotype Male. Body elongate, subparallel, dorsum moderately convex (Fig. 43). Length, 2.5 mm; greatest width, 1.1 mm. Body dark brown dorsally; venter dark brownish black (Fig. 44). Base of antenna and base of femora light to medium brown. Dorsal and ventral surface densely covered with short recumbent setae (Figs 43 and 44). Setae golden, and lacking greenish iridescence. Surface microreticulate, with dense fine punctures; fine punctures separated by distance equal to puncture diameter and coarse punctures confluent to separated by 1-3 times puncture diameter.

Head moderately coarsely, densely punctate; punctures separated by their diameter; cuticle microreticulate. Clypeus with anterior margin truncate; angle on each side broadly rounded. Labrum with anterior margin entire and gently arcuate; angle on each side broadly rounded, with row of dense, long golden setae. Eyes hemispherical, narrowed posteriorly and bordered by long black curved setae ( “eyelashes”) that arise near dorsal and ventral sides of eyes and extend toward middle of eye. Antenna pubescent, filiform, nearly serrate (Fig. 44); basal antennomeres I and II medium to light brown, with long setae, longer than width of segments, and dense recumbent setae; antenna lacking club. Antennae long, reaching past transverse groove of pronotum. Apical antennomeres dark brownish black, with dense recumbent setae (Fig. 44). Apical antennomere rounded.

Pronotum 1.2 mm long, 1.1 mm wide; lacking sublateral groove (Fig. 43); lateral margins slightly sinuate; anterolateral angles square, not explanate or depressed; base of pronotum slightly sinuate and with broad lobe medially; posterolateral angles obtuse, slightly explanate, declivous, depressed adjacent to each angle; discal area with fine, dense punctures, punctures separated by a distance equal to or less than their diameter; cuticle microreticulate. Pronotal disc lacking median longitudinal depression, with weak postero-medial impression; disc with sparse, short setae (Fig. 43). Lateral projection of hypomeron acute. Prosternum short in front of procoxae; lacking tuft of setae and dense golden setae apicomedially (Fig. 44). Prosternal process triangular, broad at base and tapering to apex; disc with V-shaped groove; lateral margins reflexed; middle moderately longitudinally cariniform; apex narrow, acute (Fig. 44). Scutellum slightly longer than broad; very strongly convex, distinctly elevated above the adjacent elytral intervals. Mesoventrite short, depressed, with a deep, broad, V-shaped depression for reception of apex of prosternal process. Metaventrite with disc inflated on posterior three-fourths, finely punctate behind mesocoxae, punctures becoming more sparse laterally, with large, rounded depressions scattered on disc; with shallow longitudinal groove on midline of disc, groove deepest and broadest on posterior third of disc; with dense, short pubescence; cuticular surface of metaventrite finely microreticulate (Fig. 44).

Legs long and slender, dark brown (Fig. 45). Procoxae and metacoxae moderately widely separated; mesocoxae slightly more widely separated. Protibia with apical rounded excavation for reception of tarsi, with apical tooth (Fig. 46). Protarsus of male expanded apicomedially. Mesotibiae of male with medial pubescent area long; lateral pubescent area only at extreme base; with fine, short, nearly longitudinal carina on inner apex. Tarsal claws long and stout, light brown. Metafemur of male with internal glabrous patch.

Elytron with ten rows of fine punctures; punctures separated by a distance three to four times the diameter of the puncture; intervals with fine, short, dense pubescence; humeral area moderately swollen (Fig. 43). Elytral striae obscured apically. Elytron widening to about posterior two-thirds before converging to strongly rounded apex (Fig. 43). Apical third of elytron strongly inflated, most evident in lateral view (Fig. 45). Elytron with strong impression at basal third. Lateral bead of elytron straight. Elytra three times as long as pronotum; broadest point across humeri but only slightly broader than broadest point at apical third; inner side of apex rounded; lateral margins smooth; humeri gibbous; elytral intervals flat; punctures on intervals no larger than finest punctures of head and pronotum and separated by 2-5 times puncture diameter.

Abdomen with five ventrites (Fig. 44). First three ventrites broadly, shallowly depressed and distinctly carinate adjacent to metacoxae; carinae extending longitudinally behind metacoxae for almost entire length of first ventrite; cuticle densely covered with setae. Last ventrite deeply and broadly emarginate (Fig. 44). Aedeagus broadly curved, with smooth apex, parameres long, reaching more than halfway up length of aedeagus (Fig. 47).

Female. Externally similar to male except inner apex of each elytron acute and slightly turned upward. Protibiae slightly less curved than those of male. Mesotibiae without carina on inner apex. Metaventral disc not as deeply and less extensively concave. Abdominal sterna 1-3 convex, not concave; apicomedial margin of third ventrite with distinct posterior projection.

Intraspecific variation.

This species varies slightly from black to dark brown in color. There are differences in size (2.5- 2.9 mm TL) and slight differences in punctation and setation.

Etymology.

This species is named “inflatus” for the distinct elytra, which appear inflated posteriorly.

Habitat and distribution.

This species is only known from specimens collected on an expedition by the University of Puerto Rico in 1950. They were collected at one locality from the upper Rio Cunucunuma in Amazonas State, Venezuela, north of Cerro Duida ( Drake and Capriles 1952) (Fig. 4). The habits and microhabitat preferences of this species are unknown.

Associated species.

Hexanchorus homaeotarsoides sp. n. occurs in the same region of Venezuela, but no other species of laraine elmid has been collected at this locality.