Argosadalia, Vandenberg, 2019

Vandenberg, Natalia J., 2019, A new monotypic genus and new species of lady beetle (Coleoptera: Coccinellidae Coccinellini) from western South America, Zootaxa 4712 (3), pp. 413-422 : 417-418

Argosadalia gen. nov.

( Figs. 1–7 , 11 a–e, 15–18)

type species: Argosadalia priscilla sp. nov.

Diagnosis. Distinguished from other members of the Neda group by a combination of: body oval, small-sized, with length 5.2 mm or less, elytral margins narrowly but distinctly explanate, with marginal bead ( Figs. 1–4 , 11a, d ). Prosternal intercoxal process lacking carinae. Elytral epipleuron ( Fig 11b, d ) narrow, with maximum width about 1/7 width of body, subhorizontal in anterior half, planar to weakly concave. Hind margin of abdominal ventrites 1–4 (inclusive of flexure bands) sublinear when abdomen is held flat ( Figs. 11b, c ); postcoxal line of first abdominal ventrite joined to oblique line and obliterated beyond, forming modified V shape ( Fig. 7 , 11b ). Basal lobe of male genitalia widest before apex, apically bifurcate, terminating in pair of parallel tapered projections separated by Ushaped emargination ( Fig. 11e , 16 ). Spermatheca of female genitalia ( Fig. 18 ) with nodulus joined to cornu to form distinct outer angle, shaped like the number “2,” but with apex of nodulus tapered distally, slightly down-curved at point of attachment to spermduct.

Remarks. Within the Neda -group the new genus resembles some of the smaller members of Neoharmonia , but the latter have the prosternal intercoxal process with a pair of convergent carinae separated by a triangular depression, abdominal postcoxal line continued laterally beyond the juncture with the oblique line ( Fig. 9 ), basal lobe of male genitalia with the apex undivided ( Fig. 12e ), and female spermatheca with a long straight tapered nodulus that flows directly from the cornu without a distinct outer angle ( Fig. 19 ).

The genus Neda has the same form of the female spermathecal capsule as the new genus and is probably closely related. However, it can be easily distinguished ( Figs. 13 a–e) by the larger body size (5.2–10.0 mm in length), broadly explanate elytral margin, epipleuron strongly concave and steeply descending externally, from about ¼–1/3 body width at widest part, hind margin of abdominal ventrite 4 distinctly arcuately emarginate in both sexes, and the basal lobe of the male genitalia widened apically, with projections diverging distally. Mononeda ( Figs. 14 a–e) also falls within the “ Neda -group” and differs from the new genus by the much larger body size (length 7.5–12.4 mm), complete lack of an elytral marginal bead, elytral margin broadly explanate, and elytral epipleuron very wide, concave and descending externally, from about 1/3–1/2 body width at widest part, with ventral epipleural carina complete to apex.

The new genus superficially resembles the Holarctic genus Adalia in its relatively small size, general body shape, and similar form of the abdominal postcoxal line ( Figs. 7, 8 ), but Adalia males have an undivided basal lobe, and a differently shaped penis with a strongly pigmented penis capsule. Adalia females have a smaller spermathecal accessory gland and the spermduct with a more robust and heavily sclerotized sheath.

Etymology. Argosadalia (gender feminine) formed from a combination of Argos (= shining, bright, from Greek) + Adalia (= noble, from Hebrew). In Greek mythology, Argos was the name of the hundred-eyed servant of the goddess Hera, who had eyes all over his body. This name was selected because of the numerous white spots on the elytra which resemble eyes. The second part of the name was used because of the superficial similarity of this lady beetle to members of the lady beetle genus Adalia .

Figures

FIGURES 1–10. External morphology of lady beetles in the tribe Coccinellini. 1–4, Argosadalia priscilla sp. nov. habitus illustrations: 1–3, holotype, male (scale bar lower left): 1, dorsal; 2, lateral; 3, frontal; 4, paratype, female (scale bar upper right), dorsal. 5–6, A. priscilla sp. nov., ventral view of mouthparts: 5, labial prementum and palpi; 6, maxillary palp. 7–10, abdominal postcoxal lines: 7, A. priscilla sp. nov.; 8, Adalia bipunctata L., 1758; 9, Neoharmonia venusta (Melsheimer, 1847); 10, Coccinella sp.

FIGURES 11–14. Genera of the Neda-group, key characters drawn from exemplars of the type species of each genus: a, body form in dorsal view, males; b, diagrammatic view of venter, males, elytral epipleuron shown in red, abdominal ventrites in white; c, apex of abdomen, female, arrow points to hind margin of 4th ventrite; d, shape of elytra in cross-sectional view through widest part; e, basal lobe of male genitalia in ventral view rescaled to the same length for comparative purposes. Scale bar applies to figures in rows a–d. 11, Argosadalia priscilla sp. nov.; 12, Neoharmonia venusta Melsheimer, 1847; 13, Neda norrisii (Guérin-Méneville, 1844); 14, Mononeda marginata (L., 1767).

FIGURES 15–19. Genitalia of lady beetles in the Neda-group. 15–17, male genitalia of Argosadalia priscilla sp. nov.: 15, left lateral view of penis; 16, ventral view of phallobase; 17, right lateral view of phallobase. 18–19, Female genitalia in dorsal view, arrows to the right of each figure show the outer angle where the cornu joins the nodulus: 18, A. priscilla sp. nov.; 19, Neoharmonia venusta Melsheimer, 1847.