Adelina bacardi, Steiner, Warren E. & Jr, 2006

Steiner, Warren E. & Jr, 2006, New species of darkling beetles (Coleoptera: Tenebrionidae) from San Salvador Island, Bahamas, Zootaxa 1158, pp. 1-38 : 15-18

Adelina bacardi , new species

( Figs. 5 A–F)

Description

Holotype, MALE: Body length 6 mm; greatest width (along mid­length of elytra) 2.3 mm.; oblong­oval, somewhat flattened dorsally, ventrally, parallel­sided along mid­length of elytra ( Fig. 5 A); color amber­brown throughout; dorsal surfaces finely alutaceous, shining but not highly so; ventral surfaces more polished.

Head ( Figs. 5 B–C) wider than long, widest anterior to eyes at laterally expanded epistoma; with transverse depression between frons and clypeus along suture; clypeus transverse, with anterior margin convex, evenly rounded, continuous with epistomal margin; epistomal margins expanded, elevated, produced anteriorly into prominent conical horns with apices curving ventrally; surface of frons with small punctures separated by about the diameter of a puncture laterally and across clypeus, becoming finer, inconspicuous, more widely spaced on vertex. Eyes narrow, wider than long in dorsal view, with truncate mesal margins; larger ventrally, wider than long. Antennae 2.7 mm long; scapus short, about twice as wide as long; pedicellus small, globular; third antennomere slightly shorter than, first two combined; antennomeres 4–11 moniliform, elliptical, slighly flattened, widest toward apices, about twice as long as wide.

Prothorax nearly as wide as hind body, widest (2.2 mm) at anterior 1/3rd; transverse, quadrate at base with acute posterolateral angles, narrower than elytra at humeri, broadly rounded at anterior corners but not inflated; sides very narrowly sinuate near base, broadly convex laterally; pronotum with lateral and posterior margins finely beaded, basal margin narrowly sinuate from sides to middle; anterior margin broadly concave, rounded. Pronotum broadly convex laterally, nearly flat across disc, with a slightly concave area basally, bearing a polished midline; basolateral foveae not deep; surfaces very finely punctate; punctures separated by two to three times diameter of a puncture. Prosternum densely punctate to transversely rugose in anterior half with many punctures coalesced; propleura more evenly punctate; prosternal process narrowed between coxae to a width only 1/4th the width of a coxa, broadly expanded posteriorly to a sloping apex, with a median furrow in area between coxae, then rounded, convex between furrow and obtusely pointed apex. Mesosternum indistinctly punctate, broadly concave medially, with a median furrow, rounded, smooth at bottom, extending to apex between mesocoxae. Metasternite finely punctate, punctures of median flat area very small, becoming larger laterally, separated by about the diameter of a puncture.

Legs with surfaces finely punctate, very finely setose; front tibia slightly arcuate, gradually widened from base to apex; outer margin nearly straight, with crenulate edge; inner margin arcuate, spurs short, thick, curved; tarsomeres unmodified except basal first tarsomere with a small conical ventral process.

Elytra about 3 times as long as wide; strial punctures small, regularly spaced, separated by about the diameter of a puncture; intervals with extremely fine scattered punctures, barely visible; edge of lateral declivity of elytron not sharply defined, beginning at the seventh stria, obscured basally on smooth, rounded humerus, obscure toward apex. Epipleurae impunctate; of even width along most of mid­length, then narrowed opposite 4th abdominal sternite to a point opposite basal 1/3rd of fifth sternite.

Abdomen with sternites punctate as on metasternite; sternites 1–3 with lateral shallow concavities surrounded by slightly raised zones; sternite 2 nearly flat to slightly concave medially; sternite 5 more that twice as wide as long, with a transverse smooth fovea along base, convex across apical half. Tegmen 1.2 mm long, arched dorsally in basal 1/3rd; sides evenly arcuate in dorsal view, widest at about mid­length of basal piece. Apical piece in dorsal view ( Fig. 5 E) widest at base, sides converging gradually, nearly straight in basal half, then curved, narrowing to rounded apex; in lateral view ( Fig. 5 F) with apex narrowly rounded, slightly deflexed. Ratio of length of apical piece to basal piece 1:2.

FEMALE. Of the same size range and coloration seen in males but, as in other Adelina species, lacking the frontal processes, with front margin of head nearly evenly rounded.

Material Examined

“ BAHAMA ISLANDS: San Salvador, Gerace Research Ctr., 24°07’N, 74°26’W, 20 February 2004 / Under bark of dead standing Terminalia catappa in mixed scrub forest; coll. W. E.Steiner & J. M. Swearingen” (holotype and 2 paratypes); same data except “ 23 June 2005 / Under bark of fallen leaning Bursera simaruba in mixed scrub forest; W. E. Steiner & J. M. Swearingen collectors” (3 paratypes); BAHAMA ISLANDS: San Salvador, near small pond 2 km W of Gerace Research Ctr.; 24°07’N, 74°28’W / 25 June 2005; W. E. Steiner, J. M. Swearingen & D. J. Lodge collectors / Under dry thin loose bark of fallen trunk and branches of Metopium toxiferum in coastal forest” (4 paratypes).

Va r i a t i o n

Some male specimens are smaller than the holotype, 4.6 to 5 mm in length; frontal horn development is much reduced ( Fig. 5 D). Most horned male beetles, including members of this genus ( Doyen 1984) typically have this kind of variation from “minor” to “major” horn development. “Minor” males may be mistaken for females.

Diagnosis

This species superficially resembles a member of the genus Sitophagus because of its more robust form and obscure elytral declivity, but the latter feature occurs on the 8th interval in Sitophagus ; S. hololeptoides Laporte , which occurs in the Bahamas, is of similar size and form, but the epistomal horns curve inward and upward, and most flagellomeres are as wide as long (see Doyen 1984). Among Adelina species, those of more robust form and having the elytral declivity on the 7th interval belong to the “second groupe” of Ardoin (1977), a group of few species compared to the “premiere groupe.” Adelina bacardi is most similar to A. dominicana Ardoin in the shape of the epistomal projections, but the tegmen of the latter ( Ardoin 1977, Fig. 20, O) has the apical piece distinctly angulate on sides, with a triangular, acute apex, not rounded.

Etymology

The color of the beetle is that of the amber­brown rum enjoyed at the symposia of the Natural History Conferences of the Bahamas, Gerace Research Center, San Salvador. The proper name “ Bacardi ,” used here as a noun in apposition, also recognizes the late Luis F. Bacardi of the family­owned distillery, whose endowment continues to support habitat conservation, and the Bacardi Family Foundation, working in partnership with the Bahamas National Trust to ensure natural resource protection in the Bahamas.

Distribution

Adelina bacardi is known only from San Salvador Island. While possibly endemic to the island, the hind wings are fully developed, so it could be far more widespread, as are many other Adelina species.

Habitats and collection notes

As noted in the label data, all were taken under loose bark of dead standing or leaning wood of a variety of tree species. Adults and associated larvae were found under thin dry bark of branches as well as main trunks, by holding a net under each piece of bark as removed, and examining the debris. The June 2005 occurrences were associated with trees broken by Hurricane Frances in September 2004.

Figures

FIGURE 5. Adelina bacardi, new species. A, holotype, dorsal view; body length 6 mm. B, same, oblique frontal view. C, same, head, enlarged; width of head 1.3 mm. D, Fore­body of a “ minor ” male paratype; width of head 1.1 mm. E­F, male genitalia of holotype, dorsal and lateral views, respectively; length of tegmen 1.2 mm.