Pygidiapion De Sousa & Mermudes, 2021

Sousa, Wesley Oliveira De & Mermudes, José Ricardo M., 2021, Pygidiapion De Sousa & Mermudes, a new genus of Apioninae (Brentidae Apioninae: Apionini) associated with Fabaceae from Brazil, with the description of a new species and transfer of Apion zikani Heller, 1922, Zootaxa 4948 (4), pp. 575-585 : 577-578

Pygidiapion De Sousa & Mermudes gen. n.

http://zoobank.org/ urn:lsid:zoobank.org:act:B7683E35-B4CC-44C9-A131-CCC4658FF354

( Figs. 1–17 )

Type species: Pygidiapion zeppelinii De Sousa & Mermudes sp. n., here designated.

Etymology. The genus name refers to the remarkable male pygidium of the type species, gender masculine.

Diagnosis. This new genus is distinguished from the other American genera by the following combination of male characters: rostrum ( Figs. 1, 3, 5 ) convex dorsally at prorostral level in side view, ventral surface with two elongate longitudinal and coarsely punctate sulci ( Figs. 5, 6 ); pronotum campaniform in dorsal view, slightly constricted before apex, slightly bisinuate with rounded median projection toward scutellum, without basal flange ( Figs. 1–4 ); scutellum glabrous and depressed in middle; hind wings with small radial window; hypomeral lobes divided by median suture and distinctly exposed sternellum; meso- and metatibiae mucronate; pygidium ( Figs. 10, 11 ) of the incomplete apionine type; basal piece fused with tegminal plate ( Fig. 14 ).

Description. Size: 1.70–2.20 mm.

Vestiture ( Figs. 1, 2 ) in general conspicuous, with sparse and homogeneous off-white scales; meta- and mesorostrum with scales reduced, absent on prorostrum; scales of head, thorax and coxae similar in size; with centripetal vestiture on pronotum, except in posterior region where scales are perpendicular to posterior margin; denser on sides of pro-, meso- and metasternum; elytral interstriae with two or three irregular rows of scales; legs with very sparse scales; uniform on abdominal ventrites; pygidium with centripetal vestiture ( Fig. 10 ).

Rostrum ( Figs. 1–7 ) cylindrical, longer than pronotum along midline; in lateral view curved, more convex at prorostral level ( Figs. 1–5 ); surface polished and finely punctate. Males with ventral surface of rostrum with longitudinal sulci punctate, squamous ( Figs. 5, 6 ).

Head ( Figs. 1–4 ) with frons slightly sloped; medially glabrous with marginal scales smaller than scales around eyes; subocular keel developed, not extending to posterior margin of eyes; area between subocular keels microreticulate, impunctate. Eyes round, convex ( Figs. 1–5, 7 ). Antennae ( Fig. 5 ) inserted at basal 0.24-0.28 of rostrum length in both sexes; scape 0.65-0.90 times mesorostral width, 4.33-5.80 times as long as wide, as long as club; pedicel longer than wide, as long as desmomeres 1+2; desmomeres 2–5 times as long as wide, desmomere 6 nearly as long as wide, subconical; club oblong and compact, 2 times as long as wide, as long as last five desmomeres; sutures marked.

Thorax ( Figs. 1–4 ). Pronotum campaniform in dorsal view, transverse, slightly constricted before apex, about 0.65-0.70 times as long as wide, base 1.40-1.60 times apical width, slightly bisinuate with rounded median projection toward scutellum, without basal flange; outline in lateral view slightly convex medially; pronotal disc with sub-basal fovea slightly depressed; punctures covered by scales. Procoxae contiguous, hypomeral lobes divided by median suture with sternellum distinctly exposed. Mesocoxa separated, mesosternal apophysis 1/3 as wide as mesocoxae, truncate at apex. Metacoxa transverse, metasternum narrowed, declivous anteriorly to metacoxa. Mesofemora slightly more robust than pro- and metafemora. Meso- and metatibiae mucronate. All tarsomeres 1 longer than wide, tarsomeres 2 wider than long, tarsomeres 3 bilobed; onychium 2.5 to 3.0 times longer than wide, surpassing lobes of tarsomere 3 by ca. 1/5 length of onychium. Tarsal claws toothed at base.

Elytral length 1.40-1.80 times distance between humeri, convex (lateral view, Figs. 1–4 ); humeri salient, formed by glabrous basal intumescences of interstriae 6; longitudinal striae present, strongly punctate apically, at apex joining 1+9, 2, 3+4, 5+6, 7+8; interstriae 7 and 9 each with one specialized seta in apical half. Apical margin of epipleura conspicuously extended. Macropterous, hind wings with small radial window ( Fig. 9 ).

Abdomen. Ventrite 1 the most elongated, impressed at disk; ventrite 2 longer than ventrites 3+4; ventrites 3 and 4 narrow; pygidium of incomplete apionine type ( Figs. 10, 11 ).

Male terminalia and genitalia. Ninth sternite (spiculum gastrale) Y-shaped ( Fig. 12 ). Penis ( Fig. 13 ) impressed and curved; pedon with apical plate straight in lateral view, rounded apically in dorsal view; tectum slender and with clear margins. Tegmen ( Fig. 14 ) with tegminal plate fused to basal piece; suprafenestral plate with macrochaetae posterior to each fenestra; fenestrae and linea arquata visible.

Female genitalia. Spiculum ventrale elongate and straight, apical plate membranous and setiferous ( Fig. 15 ). Ovipositor ( Fig. 16 ), coxite long with microchaetae; styli subcylindrical and with macrochaetae. Spermatheca Cshaped ( Fig. 17 ), lacking nodulus or ramus; cornu and corpus evident.

Sexual dimorphism. Female differing from male in having longer and wider body; rostrum narrower and more slender ( Figs. 2, 4 ); and ventral surface at mesorostral level without ventral sulci ( Figs. 7, 8 ).

Included species. Two nominal species from Brazil, one transferred from the Palearctic and Nearctic genus Apion Herbst, 1797 : Apion zikani K.M. Heller, 1922 , associated with Dalbergia foliolosa Benth. ( Fabaceae , Papilionoideae ); and one new species, Pygidiapion zeppelinii De Sousa & Mermudes sp. n., associated with Pterocarpus violaceus ( Fabaceae , Papilionoideae ).

Figures

FIGURES 1–8. Pygidiapion zeppelinii sp. n.: holotype male (1) and paratype female in lateral view (2); SEM micrographs of male (3) and female (4) in lateral view, head (5) and rostrum of male (6); head (7) and rostrum of female (8).

FIGURES 9–17. Pygidiapion zeppelinii sp. n.: hind wing (9); male pygidium, dorsal view (10) and lateral view (11); spiculum gastrale (12); penis, dorsal view (13); tegmen, dorsal view (14); spiculum, ventral view (15); coxite and styli (16); spermatheca (17).