Diaprepes abbreviatus (Linnaeus) 1758

Franz, Nico M., 2010, Redescriptions of critical type species in the Eustylini Lacordaire (Coleoptera: Curculionidae: Entiminae), Journal of Natural History 44 (1 - 2), pp. 41-80 : 49-56

Diaprepes abbreviatus (Linnaeus) 1758 , p 386

( Figures 3–7 )

Description

Male ( Figure 3A–F ). Length 8.65–17.95 mm, width 3.06–6.74 mm; shape oval to elongate, length/width ratio 2.50–2.83 (n = 10); greatest width near central region of elytra. Setae irregularly arranged, appressed to recurvate, aurate or white; scales irregularly arranged, separated (exposing integument) to overlapping (covering integument), oval to spatulate, apically rotundate to irregular, truncate to fimbriate, appressed to erect, pale yellow, pale white, or pale rosy (iridescent); pale whitish to yellowish scales with arranged in a distinct, patch- or stripe-like pattern on head, pronotum, prosterna, elytra, and ventral sterna.

Mouthparts. Mandibles with approximately 10 setae adjacent to scar. Maxillae ( Figure 5A ) with cardo arcuate; stipes angulate, apical half directed mesally, apically slightly widened, truncate, lateral margin with two to four short setae, apical region with longer and more coarse setae, transversely strigulate; galeo-lacinial complex extending to midpoint of maxillary palpomere II, mesal margin with nearly 10 very long setae and 5 lacinial teeth; palpiger with 2–3 rows of setae along apicolateral margins; maxillary palpomere I nearly 1.5 times as long as II; II similar in length to III. Labium ( Figure 5B ) with prementum subtriangular to escudate, apical margin medially slightly projected; ventrally with four to six evenly spaced long setae on each side, apicocentral region with short setae transversely arranged; labial palpomere III slightly protruding from apical margin of prementum; I slightly longer than II; II slightly shorter than III.

Rostrum. Length 1.28–2.66 mm, rostrum/pronotum length ratio 0.57–0.67, rostrum length/width ratio 1.32–1.48. Dorsal outline of rostrum rectangular; dorsolateral margins subparallel, slightly widened at antennal insertion, evenly convex. Nasal plate small, slightly projected from anterior region of rostrum, posteriorly forming a tumescent triangular border. Epistoma slightly depressed, with several isolated, recurvate setae. Dorsal surface of rostrum subplane, with transverse, slightly angulate carina along posterior edge of epistoma, median line carinate, extending from antennal insertion to midpoint between eyes, with two dorsolateral carinae, each extending to anterior margin of eye, anteriorly slightly diverging, scales directed mesally; ventrolateral margins emarginate, centrally constricted. Ventrolateral regions of rostrum and head on each side with one wide stripe of appressed, whitish iridescent scales. Antennal insertion near anterior fifth. Scrobe slightly sinuate, extending to anterior margin of eye.

Antennae with scape covered exclusively with setae. Funicular antennomeres progressing from elongate to equilateral; II distinctly longer than I. Club similar in length to funicular antennomeres III–VI, nearly three times longer than width; I and II similar in length, III and IV each slightly shorter.

Eyes subcircular, margins partially straight, slightly angulate relative to each other; eyes separated from anterolateral margin of pronotum by nearly 10 rows of scales, interocular distance distinctly shorter than maximum width of eye; with nearly 30 facets along maximum diameter.

Head with dorsal margin surrounding each eye with two to three rows of appressed, whitish scales, frons with median carina extending from frontal fovea to anterior region of occiput.

Thorax. Pronotum equilateral to trapezoidal, length/width ratio 0.88–0.98, pronotum/elytra length ratio 0.31–0.33; greatest width near central region; dorsal surface slightly concave, irregularly punctate, with evenly spaced yet variously shaped lacunae, each covered by 5–15 scales; whitish scales also covering median sulcus. Anterodorsal margin nearly two-thirds the length of posterodorsal margin; posterodorsal margin straight to slightly bisinuate. Pronotum in lateral view subquadrate to conical, with foveate to longitudinal impressions above procoxal cavities, with a wide stripe of whitish appressed scales interspersed with slightly narrower, erect, longitudinally slightly plicate scales; anterolateral margin nearly straight, without postocular lobe, yet with postocular vibrissae of various lengths. Scutellum subcircular, glabrous, margins finely setose. Mesepimeron with plumose scales along dorsal and ventral margins, posterior margin with lamellate, whitish iridescent scales.

Prosternum nearly 1.5 times as long as mesosternum, anterior and posterior intercoxal projections elevated. Mesosternum nearly half as long as metasternum, anterior half covered with elliptical, plumose scales. Metasternum with median sulcus extending along posterior third, forming a large median fovea; metacoxal cavities separated by distance nearly 3/5 width of each mesocoxal cavity. Metendosternite as in Figure 5C .

Legs. Prothoracic legs longer than mesothoracic legs. Procoxa with most proximal scales plumose. Profemur/pronotum length ratio 1.27–1.41; profemur straight, in cross-section elliptical. Protibia/profemur length ratio 1.05–1.13; protibia arcuate, in cross-section subcircular; ventral margin with several rows of long, aurate setae; and with row of 8–12 cuticular teeth; protibial apex with anterior margin truncate; setal comb absent; mucro shorter than tarsal claw, surpassed by 2–3 groups of reddish brown setae. Protarsus with tarsomeres I and II equilateral. Mesotibia slightly shorter than metatibia, slightly arcuate, with small lateral region covered with whitish scales similar to those of pronotum. Metatibial apex with anterior margin slightly arcuate.

Elytra. Length/width ratio 1.82–1.94; greatest width at humeri or near central region; anterior margins jointly wider than posterior margin of pronotum, not projected; lateral margins subparallel along anterior two-thirds, gradually arcuately converging along posterior third; posterior margins slightly arcuate. Elytra with 12 complete striae; striae narrower than intervals; stria X complete; punctures narrowly separated by distance shorter than width of each puncture; intervals subplane to strongly convex: intervals of mesal margin/I and VIII/IX elevated, glabrous along anterior three-quarters, intervals of IV/V and XII/lateral margin similar along anterior half, and interval IX/X similar along anterior two-fifths, glabrous intervals jointly producing characteristic pattern of elytral striation; strial intervals covered evenly and contiguously (though see earlier) with whitish to pale yellowish scales: appressed, oval scales densely interspersed with erect, narrower, spatulate, apically pectinate to truncate scales.

Wings ( Figure 5D ) with wing/body length ratio 1.12–1.15, wing length/width ratio 3.42–3.48 (n = 4); anterior margin slightly sinuate; posterior margin nearly straight.

Abdomen. Ventral sternum III centrally subplane, laterally slightly convex; suture separating III and IV mesally shallow, laterally deeper; straight; V and VI jointly similar in length to IV; VII with posterior margin slightly arcuate; lateral margins of ventral sterna with symmetrical, subtriangular patches of whitish scales similar to those of pronotum. Pygidium trapezoidal; posterior margin slightly arcuate, mesally deeply and widely emarginate, ventrally plicate.

Terminalia. Sternum VIII ( Figure 6A ) consisting of two subrectangular sclerites; posterior margin of each sclerite with six to eight longer setae. Spiculum gastrale ( Figure 6B ) similar in length to median lobe; posteriorly bifurcate (Y-shaped), furcal arms triangular, margins not serrate, subparallel. Tegmen ( Figure 6C ) slightly shorter than median lobe. Aedeagus ( Figure 6D ) with median lobe length/width ratio 5.28–5.78 (n = 4); lateral margins subparallel along most of length, anterior one-sixth slightly expanded (alate); apex triangularly narrowed, narrowly rotundate. Median lobe in lateral view evenly deflexed; width gradually narrowed towards apex; apex acutely narrowed, slightly reflexed. Internal sac with one centrally positioned, subdivided, tubular sclerite, anterior region consisting of two larger, posteriorly slightly diverging sclerites, posterior region with a narrower, slightly sinuate sclerite, surrounded by triangular laminar projection from paired anterior sclerites; ventral region along ostium with three narrow, explanate sclerites, median sclerite with two evenly spaced nodular expansions. Adeagal apodemes nearly two-thirds length of median lobe.

Female. Length 10.36–21.78 mm, width 4.41–8.51 mm; length/width ratio 2.34–2.56 (n = 10); greatest width at humeri to posterior one-third of elytra. Rostrum length 1.61–3.01 mm, rostrum/pronotum length ratio 0.60–0.72, rostrum length/width ratio 1.24–1.36. Pronotum length/width ratio 0.76–0.86; pronotum/elytra length ratio 0.27–0.32; greatest width at posterior margin. Metasternum ventrally subplane, concave in posterior half, posteromedian region deepened into a distinct fovea. Protibia/ profemur length ratio 0.91–1.15. Elytra length/width ratio 1.65–1.89; outline of declivity slightly emarginate; scales along strial intervals X–XII pale orange. Venter with sterna III and IV centrally subplane, laterally slightly convex; VII triangular, posterior margin of VII narrowly arcuate. Pygidium with posterior margin acutely narrowed, projected.

Terminalia. Tergum VII with wide median stripe of long setae; posteriorly with V-shaped region of long setae forming dense patch at posterior edge. Sternum VIII ( Figure 7A ) with anterior half stylate; posterior half narrowly triangular, spatulate, medially fused (not bifurcate); otherwise as in C. argyreus . Coxites and styli as in Figure 7B . Genital chamber nearly half as long as sternum VIII. Spermatheca ( Figure 7C ) Z-shaped; ramus not projected, corpus short and wide, inner side with slight inflexion; collum slightly projected, opposed to orientation of cornu; cornu (apical half) slightly sinuate, apex narrow, arcuate, deflected.

Variation

The overall size and patterns of elevated strial intervals versus the colour and extension of elytral scales are highly variable in this widespread species, and correspond to geographically recognizable “morphs” that nevertheless appear conspecific in light of their identical male terminalia (see also the very thorough expositions of Pierce [1915] and O’Brien and Kovarik [2001]). Among the examined specimens the number of scaleless strial elevations varies from three to seven, where specimens with the highest numbers have alternating primary (longer and thicker) and secondary (shorter and thinner) intervals of variable positions (anterior, near midpoint, posterior) on the elytra. Scale colour varies from (pale) white to various and not necessarily homogeneous shades of yellow to rusty brown or nearly orange, or with limited pinkish regions (populations near Aguada, Puerto Rico).

The patterns of strial elevations and scale coloration of Linnaeus’ type specimen ( Curculio spengleri, UUZM #1735; Figure 4 ) are most reminiscent of those observed on specimens collected along the northern coast of Puerto Rico (e.g., Aguadilla, Isabela, and El Yunque). Marshall (1916: 453) stated that the type specimen was collected in Martinique; however, it is unclear where he obtained this information. Linnaeus provided only the following details: “Indiis” ( Linnaeus 1758: 386) and “Habitat in America” ( Linnaeus 1767: 609–610). O’Brien and Wibmer (1982: 55–56) listed several islands including Martinique and Puerto Rico as localities for D. abbreviatus yet only Puerto Rico for (the now synonymized) D. spengleri . Efforts are underway to understand the phylogeographic history and ongoing differentiation between populations of this interesting species ( Ascunce et al. 2008).

Specimens examined

“ Puerto Rico, Bosque Estatal Maricao, Rte. 120, km 9.2, 690 m, 18°08′04″N, 66°57′18″W /Beating plants, leg. N. Franz and J. Metcalf, VII-28-2006 ” (two males and two females, UPRM). Other conspecific material seen from Adjuntas, Aguada, Aguadilla, Bosque Estatal Susúa, El Yunque , Fortuna , Guánica, Isabela, Lares, Mayagüez, Mona Island , Ponce, San Sebastián, Vieques Island , and Yauco (all localities from Puerto Rico; housed at UPRM) .

Figures

Figure 3. Habitus of Diaprepes abbreviatus, male. (A) Dorsal view; (B) lateral view; (C) ventral view; (D) head, dorsal view; (E) head, lateral view; (F) metatibia, lateral view.

Figure 4. Type specimen of Diaprepes abbreviatus, male. (A) Dorsal view; (B) type labels. Note: Photographs by Dr. Hans Mejlon (Museum of Evolution, Uppsala, Sweden). Reproduced with permission.

Figure 5. Mouthparts and thoracic structures of Diaprepes abbreviates. (A) Right maxilla, ventral view; (B) labial prementum, ventral view; (C) metendosternite, posterior view; (D) right wing.

Figure 6. Terminalia of Diaprepes abbreviatus, male. (A) Sternum VIII, ventral view; (B) spiculum gastrale, ventral view; (C) tegmen, ventral view; (D) aedeagus, ventral view and lateral view.

Figure 7. Terminalia of Diaprepes abbreviatus, female. (A) Sternum VIII, ventral view; (B) posterior region of coxites and styli, ventral view; (C) spermatheca.