Apterodina achuparia Flowers

Flowers, Wills, 2009, A second species of Apterodina (Chrysomelidae: Eumolpinae) from Ecuador, Zootaxa 2131, pp. 65-68 : 65-67

Apterodina achuparia Flowers , new species.

( Figs. 1–10 )

Holotype Male. Length 3.3 mm. Head, pronotum, elytra and underside shining coppery-black; antenna and apical three segments of the abdomen reddish brown. Legs dark reddish brown ( Figs. 1–2 ). Apex of labrum rounded, clypeus and vertex microreticulate with strongly aciculate punctures. Prothorax distinctly wider than long, L/W = 0.63; pronotum strongly convex, anterior angles acute, directed antero-laterally; lateral margins narrow, undulate at middle, strongly converging in apical third, with widest part of pronotum anterior to middle; disc regularly, finely punctate, with punctures separated by a distance greater than their own diameters, and with fine punctulae between punctures. Prosternum large and trapezoidal behind coxae, with long setae, surface wrinkled; intercoxal process shallowly concave, its posterior margin weakly convex, lateral angles quadrate; width of intercoxal process 0.8 x diameter of procoxa. Mesosternum flat between coxae, strongly depressed anterior to mesocoxae, wrinkled with long yellow setae. Metasternum narrow between meso- and metacoxae, alutaceous, with short yellow setae. Metendosternite Y–shaped, basal stalk short, lateral arms narrow ( Fig. 10 ). Elytra inflated, punctate in disorderly rows, punctures becoming weak in apical fourth, with punctures separated by distance greater than the diameter of a puncture; surface between punctures smooth with scattered small punctulae; humeri not prominent, broadly rounded, width across humeri subequal to width across pronotum; basal calli obsolete; postbasal depression lacking. Sides of elytra broadly rounded, convergent; apices rounded. Inner surface of elytra lacking binding sites. Hind wing reduced to a narrow strap ( Fig. 9 ), vein R thick, a field of short seta at its apex. Tip of wing folded back over wing surface in living beetle. Scutellum V-shaped. Abdomen with scattered prostrate setae; surface of segments alutaceous. Sternum VII with lateral margins smooth, a weak depression in center. Median lobe in lateral view smoothly curved ( Fig. 5 ); apex broadly rounded with median point ( Fig. 7 ); basal hood long, lightly sclerotized, with apodemes distinct at lateral margins of hood; subbasal fenestra present; basal spurs prominent; tegmen triangular; apical sclerite small, rod shaped ( Fig. 6 ).

Allotype Female. Length 4.6 mm; color similar to male ( Figs. 3–4 ). Head with labrum, frons, clpyeus and antennae similar to male; mouthparts similar to male. Prothorax distinctly wider than long, L/W = 0.65; pronotum as in male, evenly punctate on disc, with punctures separated by distance equal to or slightly greater than their own diameters. Prosternum similar to male, but with width of intercoxal process 1.2 x diameter of procoxa; somewhat smoother and more inflated between procoxae, posterior margin straight. Mesosternum, metasternum and metepisternum as in male. Elytra with scattered punctation in basal two thirds, becoming punctate-striate in apical third. A strong lateral carina runs along lateral margin of elytra above epipleuron; carina interrupted behind humerus ( Fig. 3 ). Abdomen with segments VIII–IX forming elongate ovipositor. Sternum VIII with a long aciculate apodeme; gonocoxae slender, with long setae in apical half, coxostyli small with long apical setae. Spermatheca ( Fig. 8 ) with pump and receptacle not differentiated, spermathecal duct long, thin, and densely coiled.

Etymology. The epithet achuparia is an arbitrary combination of letters derived from Achuparias, the name of the township where this species was discovered.

Specimens examined. (3 ♂♂, 2 ΨΨ) Male HOLOTYPE labelled: ECUADOR, Bolívar, Achuparias, Guaranda–Caluma hwy. betw. Km 7 & 8. S01.59971; W079.05371; 3019m. 26–ene–2008. R.W. Flowers (MECN). Female ALLOTYPE (same data as holotype)(MECN). PARATYPES (2 ♂♂, 1 ΨΨ) same data as holotype) (FSCA).

Discussion. Of the known species of Apterodina , A. achuparia and A. granulifera Bechyné have sexually dimorphic elytra with sublateral costae in the female of A. achuparia and posthumeral tubercles in A. granulifera (known only from the female). Apterodina achuparia differs from A. bechynei Flowers , A. bucki Bechyné , and A. ruminyahui Flowers in having a distinct greenish sheen in both sexes (the other species are black, bronzy black, or dark brown, Flowers 2004). The hind wings of three of the known species of Apterodina ( A. achuparia , A. bucki , and A. bechynei ) are vestigial but retain a well developed R vein with a field of short setae at its apex. Other veins are weakly indicated, with A. achuparia showing more vein traces than the other two species.

With new knowledge of the genus provided by the discovery of A. achuparia , Apterodina now appears to be related to a complex of Neotropical taxa in which a propensity to strong sexual dimorphism in the development of the female elytra is expressed. The widespread genus Brachypnoea Gistl is the most familiar of these taxa. As in Brachypnoea , some, but not all, Apterodina have more strongly sculptured elytra in the females. This character is most strongly expressed (when it is) laterally around the humeri, where the male siezes the female during copulation. This raises the possible explanation of differential sexual selection, as recently described in the Dytiscidae ( Bergsten and Miller 2007) , but observations focused on this possiblity have not yet been made for the Eumolopinae.

The known species of Apterodina can be separated with the following keys (updated from Flowers (2004).

Figures

FIGURE 1 – 4. Apterodina achuparia. Figs. 1 – 2, holotype male: 1, dorsal view; 2, lateral view. Figs. 3 – 4. allotype female:.

FIGURES 5 – 10. Apterodina achuparia. Figs. 5 – 7, male genitalia: 5. median lobe; 6, apical sclerite; 7, apex of median lobe. Fig. 8, spermatheca. Fig. 9, hind wing. Fig. 10, metendosternite.