Neacratus antennatus Mantilleri, Lanuza-Garay, and Bartolozzi

Mantilleri, Antoine, Lanuza-Garay, Alfredo & Bartolozzi, Luca, 2014, A New Species of the Genus Neacratus Alonso-Zarazaga, Lyal, Bartolozzi, and Sforzi (Coleoptera: Brentidae: Acratini) from Central America, The Coleopterists Bulletin 68 (4), pp. 757-761 : 758

Neacratus antennatus Mantilleri, Lanuza-Garay, and Bartolozzi , new species

Holotype. ♂, Panama, Isla Barro Colorado , light trap, 22-28.IV.1987 ( MIUP).

Paratypes. 1 ♂, idem holotype ( PCMENT) ; 1 ♀, idem, 25.II-3.III.1987 ( MIUP) ; 2 ♀, idem, 13-19.V.1987 ( MNHN EC4548 , MZUF 1 7 3 3 5) ; 1 ♂, Panama, dist. Chepo, Altos de Maje , 17.V.1975, at lights, Stockwell & Engleman ( MNHN EC4549 ) ; 1 ♀, Panama: Canal Zone, Barro Colorado Island , 22.V.1973, at light, H. Wolda ( CMNC) ; 1 ♀, Costa Rica, Estación Maritza, 600 m, W side Volcan Orosi, Guanacaste Pv. , 18.II.1988, D. H. Janzen & W. Hallwachs ( CMNC) .

Description. Length from tip of rostrum to apex of elytra: 10.5–13.7 mm; width across humeral calli: 1.8–2.4 mm. Body ferruginous, elytra with dark post-median blotch. Habitus: Figs. 1–3 .

Male. Head: Short ( Figs. 10–11 ), glabrous, not grooved, with quite large, shallow punctures on the posterior part; eyes longer than temples, hardly prominent, collar constriction weak; no interocular fovea. Metarostrum smooth, broad, very short, mesorostrum extremely developed and flattened, forming kind of blade above antennae. Mesorostrum and metarostrum with thin, weak median groove. Prorostrum glabrous, as large as metarostrum, strongly notched at apex in middle. Mandibles small. Side of head with quite large but shallow punctures behind eyes; rostrum not punctate. Venter of head glabrous, smooth, with distinct post-ocular median fovea; venter of meta- and mesorostrum with 2 elevated carinae converging on mesorostrum. Venter of prorostrum smooth, glabrous. Antennae ( Figs. 13–14 ) 11-segmented, with very large scape more than 5X longer than segment 2 and almost 2X wider. Antennomeres 1–8 covered with very small, hook-like setae and a few longer, straight setae; 9–11 with less dense but longer setae; from above, segments 2–10 globular; in side view, segment 5 and especially segment 7 extending downwards, with longer setae at apex of extension; 9–10 similar to 5; 11 more than 2X longer than 10, acuminate, laterally compressed. Thorax: Pronotum slightly longer than broad, longitudinally grooved, covered with large, shallow punctures. Scutellum not foveate, rounded at apex, not inserted between elytra. Base of elytra well distinct, without any hole or depression in area of insertion on mesonotum. Elytral striae 1–2 distinct from base to apex, punctate; striae 3–8 strongly punctate; 9 not distinct at base, then punctate, and finally distinct in last two-thirds; 10 punctate and quite distinct at base, vanishing after first third. Apex of elytra ( Fig. 16 ) with striae 2–3 connected, forming loop; apex largely expanded downwards, border of expansion consisting of interstria 9 (expansion reduced to small protuberance directed downward at apex of interstria 9 in one specimen, and not smallest one). Prosternellum distinct. Mesanepisternum and mesepimeron punctate; metanepisternum with line of distinct punctures. Metathorax punctate at sides, longitudinally grooved. All legs ( Fig. 15 ) with femur and tibia strongly flattened laterally, blade-like; all femora glabrous, with large expansion below at base; tibiae covered on almost their entire surface by short, thin setae; apex of tibiae with 2 small spurs. Tarsi of all legs very similar, segments 1–3 globular, covered with same hook-like setae as on antennae; 5 much longer. Abdomen: Short ( Fig. 17 ), sternites III and IV much broader than long, punctate mostly at sides; sternites III-IV not depressed, sometimes with weak longitudinal groove; suture between sternites III and IV distinct; apex of sternite IV abrupt. Sternites V-VII densely shallowly punctate. Sternite VII almost glabrous. Tergite VIII ( Fig. 18 ) truncate at apex, with short hairs. Sternite VIII ( Fig. 7 ) hairy at apex; sternite IX ( Fig. 7 ) with accessory gland; no small sclerite between sternites VIII and IX. Tegmen ( Fig. 8 ) with very large basal apodeme; parameroid lobes short, acuminate, with a few hairs only at apex. Median lobe ( Fig. 9 ) rounded at apex, with quite long basal apodemes; frena missing; sclerite of internal sac well-developed, with posterior rod and, at base of this rod, 2 lateral paramedian expansions; no spicules in internal sac.

Female. Similar to male except prorostrum not enlarged ( Fig. 12 ) but cylindrical and hardly notched at apex, and sternites III-IV of abdomen not grooved. Shares with male same peculiar structure of antennae and legs and same elytral expansions. Tergite VIII ( Fig. 5 ) with blunt teeth at apex. Genitalia: Epipleurite VIII ( Fig. 4 ) with short apodeme and large accessory gland; spermatheca ( Fig. 6 ) large, with several basal constrictions, spermathecal duct short; 2 accessory glands. Dissection of the female genital tract of one of the individuals revealed the presence of three large ovoid eggs (1.0 mm long, 0.6 mm broad).

Etymology. The specific epithet derives from the very special shape of the antennae.

Remarks. The type species of the genus Neacratus , N. glabratus (Lund, 1800) , was recently reviewed by Mantilleri (2014a). Externally, N. antennatus is very different, especially in the shape of the antennae, the flattened rostrum, and the elytral apex. However, it shares with N. glabratus the smooth metarostrum, without median carina or groove, the head not well-separated from the neck, the femora short and flattened at base, without tooth. The male genitalia also have similarities: median lobe rounded at the apex, apodemes well-developed and frena reduced (but not missing in N. glabratus ). The shape of the sclerite of the internal sac is, on the contrary, very different, while some other species of Neacratus , such as N. brevicostatus Kleine, 1922 , and N. famulus Boheman, 1840 , are very similar with regard to this character, the shape of the tegmen, and the lack of frena. So, despite the unusual habitus, we think it is better for the moment to assign this species to Neacratus .

Figures

Figs. 1–9. Neacratus antennatus. 1) Male, dorsal view; 2) Male, lateral view; 3) Female, dorsal view; 4) Female, epipleurite VIII; 5) Female, tergite VIII; 6) Female, genital tract and spermatheca; 7) Male, sternites VIII-IX; 8) Tegmen; 9) Median lobe.

Figs. 10–18. Neacratus antennatus. 10) Male, head, dorsal view; 11) Male, head, ventral view; 12) Female, head, dorsal view; 13) Antenna, dorsal view; 14) Antenna, lateral view; 15) Left posterior leg, lateral view (hairs covering the legs not figured); 16) Apex of left elytron, lateral view; 17) Male, abdomen, venter; 18) Male, tergite VIII.