Eugnamptus basalis Sharp

Hamilton, R. W. & Novinger, A. L., 2004, Eugnamptine weevils of La Selva, Costa Rica (Coleoptera: Rhynchitidae), Zootaxa 610, pp. 1-43 : 38-39

Eugnamptus basalis Sharp

( Figs. 12 , 24 )

Eugnamptus basalis Sharp, 1889: 31 Eugnamptus godmani Sharp 1889: 32 Type locality. Panama, Volcan de Chiriqui.

Type holder. BMNH

Lectotype designation. The three male syntypes are card mounted with the following label data: (1) Eugnamptus basalis , Type, D.S., V. de Chiriqui (on card with specimen); Type (circular label with red border); V. de Chiriqui below 4,000 ft., champion; BCA Col. IV.3, Eugnamptus basalis Sharp ; (2) Eugnamptus basalis , D.S., V. de Chiriqui, 4,000 ft., Champion(on card with specimen); (3) Eugnamptus basalis , D. S., V. de Chiriqui (on card with specimen). The first male with the right antennae missing and the left antennae missing the middle and terminal club segments, is designated as lectotype.

Size range. Male: 3.7 x 1.4 mm to 4.5 x 1.6 mm; Female: 4.5 x 1.6 mm to 4.9 x 1.8 mm.

Description. Male: Head slightly longer than wide, punctures very small, widely spaced; gena about as long as ½ longitudinal diameter of eye; longitudinal diameter of eye shorter than length of rostrum; frons subequal in width to rostral base, with small weakly impressed central fovea. Rostrum subequal in length to head, widened beyond antennal insertions; width at apex slightly wider than frons. Antennae inserted at middle of rostrum; club longer than funicle; segment 1 of funicle ovo­globose, ½ as long as scape; segments 2–6 slender, weakly clavate, longer than segment 1; segment 7 similar to 2–6 but shorter, more cylindrical; club with basal segment shorter than middle segment; terminal segment ½ as long as middle segment. Pronotum longer than wide, moderately punctured; punctures weakly impressed; distance between punctures subequal to ½ diameter of puncture, flattened dorsally, widest at middle, anteriorly constricted. Elytra almost twice as long as wide; widest at apical third; striae distinct and similar throughout; intervals weakly convex, slightly narrower than width of striae; row of semi­erect setae on strial interspaces; row of erect setae on intervals; next to last strial row joins last strial row beyond middle of elytra. Female: Same as male except rostrum longer than head, more arcuate; more flattened apically; width at apex subequal to width of frons; antennae inserted near basal 1/3 of rostrum; and frons slightly wider than width of rostral base.

Color. Male: Body and legs reddish brown to yellowish brown; antennae and sides of rostrum darker; each elytron with blackish brown mark in basal 1/5; mark with irregular posterior margin; basal mark sometimes as separate marks on humeri and near scutellum. Female: Same as male except elytra brownish black with narrow reddish brown margin that is expanded across the midbase or elytra brownish black with margin lacking along elytral suture; femoral apices, tibiae and tarsi blackish brown.

Comments. Fifty­six specimens were examined. The females of E. basalis can be confused with the females of E. suturalis since both have pale margined elytra ( Figs. 23 c & 24c). However, in females of E. basalis the reddish­brown margin along the elytral suture is either expanded into larger areas across the midbase ( Fig. 24 d) or completely lacking with the area along the elytral suture dark. In addition, the rostral apex is more widened, flattened and laterally punctate in females of E. suturalis . The males of E. suturalis have the same color pattern as the females while the males of E. basalis are reddishbrown throughout with dark markings only at the base of the elytra ( Fig. 24 b). Sharp (1889) described the female of this species as E. godmani . The pedon is parallel­sided and narrows abruptly at the apex into a very small v­shaped median notch ( Fig. 12 b). This species was primarily collected in malaise traps although a few were collected by hand with beating sheets.

Figures

FIGURE 23. Eugnamptus suturalis Sharp; a – b (male), c – d (female).

FIGURE 24. Eugnamptus basalis Sharp; a – b (male), c – d (female).

FIGURES 7 – 12. Male genitalia, Eugnamptine spp., line = 1 mm. a) Tegmen, dorsal view, b) Median lobe with endophallic sac and TA in repose, ventral view: 7) E. longiusculus 8) E. bellus 9) E. sarapiquensis 10) E. balius 11) E. suturalis 12) E. basalis