Rhabdorrhynchus, 2008

Meregalli, Massimo, 2008, Taxonomic relationships between Pachycerus and Rhabdorrhynchus (Coleoptera: Curculionidae: Lixinae), with descriptions of two new species of Rhabdorrhynchus from the Arabian Peninsula, Zoological Journal of the Linnean Society 152 (1), pp. 25-37 : 31-33

RHABDORRHYNCHUS EMIR SP. NOV.

Type locality: United Arab Emirates, Jebel Ali , 24°59′N, 55°43′E .

Holotype ♀, United Arab Emirates: United Arab Emirates, Umg [ebung] Jebel Ali, 24°59′N, 55°43′E; Dünen am Strand, 15 March 1990, H. J. Bremer legit ( NHMB).

Paratype ♂, United Arab Emirates: United Arab Emirates, Dubai Emirate, 55°40′18″E, 24°56′07″N, 16 April 1993, Barbara J. Tigar / Brit. Mus. 1994-180/262 ( BMNH) .

Diagnosis: A Rhabdorrhynchus very similar to R. sauditus sp. nov., characterized by the short, flat rostrum, with scarcely developed dorsolateral keels; the pronotum scarcely convex, with flat, nonimpressed narrow median line, and convex, irregular granules flattened on top; the ventrite VIII of the female with moderately broadened arms and the hemisternites long tapering at apex.

Measurements: Holotype ♀. Body length including rostrum, 7.56 mm. Rostrum: length, 1.40 mm; width, 0.74 mm. Pronotum: length, 2.23 mm; width, 2.46 mm; ratio, 0.91. Elytra: length, 4.95 mm; width, 3.07 mm; ratio, 1.61. Ratio of elytral to pronotal length, 2.22; ratio of elytral to pronotal width, 1.25. Paratype ♂. Body length including rostrum, 5.72 mm. Rostrum: length, 1.01 mm; width, 0.59 mm. Pronotum: length, 1.79 mm; width, 1.92 mm; ratio, 0.93. Elytra: length, 3.78 mm; width, 2.42 mm; ratio, 1.56. Ratio of elytral to pronotal length, 2.11; ratio of elytral to pronotal width, 1.26.

Description: Body of small size, integument moderately glossy, dark reddish at base of elytra, progressively darkened, black on pronotum; vestiture composed of narrow, hair-like, yellowish scales and larger, elliptical, acuminate white scales, about five times longer than broad, glossy, generally covering integument where present ( Figs 16, 17 ).

Rostrum slightly longer than wide, nearly straight in lateral view, moderately thickened at apex. Dorsolateral keels broad but barely developed, densely and roughly punctured, slightly more raised and smoother only above eyes, sinuate and converging anteriad towards antennal insertion, in lateral view nearly straight from base to antennal insertion, barely curved downwards at middle of the rostrum length; dorsum flattened or subdepressed, lacking distinct furrows or keels, delimited by the dorsolateral keels and thus narrowed anteriad between antennae, roughly wrinkled and punctured, interspaces between wrinkles raised to form irregular small glossy granules; sides in front of eyes flat, densely wrinkled and punctured. Epistoma semicircular, well delimited, broadly punctured, and nearly matt, concave at apex. Vestiture: yellowish-white hair-like scales inserted in granules and punctures, relatively dense; larger white scales forming a stripe on median part, hiding integument. Scrobes short, deep; upper margin moderately convex and raised above antennal insertion, not expanded outwards, straight, reaching the lower margin of eyes; lower margin of scrobes not delimited by a glossy smooth keel, short, directed downwards ( Figs 20, 25 ). Antennae with scape short, thick, conical, straight, and moderately broadened from base; funicle nearly as wide as scape at its apex, segment 1 subcylindrical, about 1.5 times longer than broad, segment 2 subquadrate, segments 3–7 transverse, seventh slightly larger; club long elliptical; vestiture of the antennae as in R. sauditus ( Fig. 22 ).

Head short, transverse, vertex convex, rough; interocular pit distinct; eyes moderately convex, their upper half visible from above, in lateral view subtriangular–elliptical, lower margin subacute. Vestiture: scattered hair-like scales and a patch of larger white scales on centre of vertex; underside with scales white, in part bifid, connate near apex.

Pronotum large, in lateral view dorsally nearly flat, base medially moderately expanded towards scutellum ; sides subparallel, from base barely widening up to apical quarter and shortly narrowing preapically in female holotype, very weakly convergent apicad in male paratype; apex prominent above head, ocular lobes weakly but distinctly developed, with some yellow setae; dorsum in holotype with irregularly shaped, sparse glossy granules, which are smaller, widely separate, and scarcely raised on disc, and larger and more glossy, in part fused, towards base, apex, and sides, where they are higher but similarly flattened in their upper part; in paratype male granules on dorsum scarcely raised, semicircular, delimiting the external margin of irregularly impressed punctures; disc with a narrow and flat median keel, continuous from base to apex, narrowed at middle, smooth, not impressed; sides with smaller, rounded, and slightly conical granules. Vestiture: hair-like scales relatively frequent on dorsum, thicker in the basal half of the median keel and on sides, progressively larger towards anterior part; large white scales forming a thick oblique stripe on the anterior part of the median line, two small elongate spots in dorsolateral position, and a scarcely defined line starting from the spots and directed towards apex ( Fig. 21 ).

Scutellum narrow, long triangular.

Elytra barely wider than base of pronotum, sides subparallel, maximum width along middle of their length, declivity oblique, gently sloping. Apex of each elytron with an acute projection behind interval 3, and with a hint of a raised keel joining the junctions between intervals 2 and 10 and intervals 3 and 9. Surface nearly smooth, with very few granules on basal part; all intervals flat, odd undifferentiated from even, striae with shallow punctures, larger at base, and progressively narrower towards apex. Vestiture: yellow hair-like scale quite dense on odd intervals and sparsely scattered on even intervals; larger white scales forming dense, vaguely delimited patches covering integument over the whole surface, leaving out small irregular spaces usually covered by hair-like scales and a slightly better delimited bare patch on intervals 2 and 4 slightly beyond median of elytra ( Fig. 19 ).

Prosternum shape, sculpture, and vestiture as in R. sauditus .

Ventrite I as long as ventrite II, ventrite I plus ventrite II as long as ventrite III plus ventrite IV; ventrites III and IV nearly half as long as ventrite II, ventrite V transverse. Vestiture very dense on all ventrites, composed of large glossy white scales, leaving out four lateral bare spots on ventrites I and II, the outer ones small and scarcely distinct, and two small median spots barely delimited and nearly completely merged; on ventrites III and IV, two lateral bare round spots and indications of a median patch, on ventrite V, indication of a bare patch at base ( Fig. 18 ). Secondary sexual characters are similar to those of P. sauditus .

Legs shape and vestiture as in R. sauditus .

Aedeagus slender, moderately curved.

Apical lamella, shortly triangular ( Figs 28–30 ).

Hemisternites broadened basad, narrowly attenuated at apex; styli subquadrate, short, apical ( Fig. 26 ).

Spermatheca with long narrow, curved and acuminate cornu, subquadrate ramus, and thickened nodulus ( Fig. 24 ).

Sternum VIII with arms thin, joined at base, moderately widened; sclerotized plate nearly indistinct, limited to a small area around apex of arms ( Fig. 23 ).

Variation: The paratype male is much smaller (5.72 mm), the pronotum has sides that are very weakly convergent apicad, and the granules on the dorsum are scarcely raised, semicircular, delimiting the external margin of irregularly impressed punctures. The other traits characterizing R. emir are constant in the two specimens examined.

Etymology: The specific epithet is a noun in apposition. It is derived from ‘emir’, also sometimes written as Amir or Ameer (arabic:, commander), a high title of nobility or office, historically used in Islamic nations of the Middle East, North Africa, and the Turkish world; in reference to the species’ provenance, the United Arab Emirates.

Ecology: The type specimen was collected on sand dunes along the beach.

Remarks: Rhabdorrhynchus emir differs from R. sauditus sp. nov. in the following traits: size smaller (5.72–7.56 mm vs. 8.40–9.79 mm), rostrum with dorsolateral keels scarcely raised throughout their entire length, densely punctured and barely distinct before antennal insertion; dorsum flat, lacking longitudinal grooves; scape shorter, straight, thickened from base (slightly curved forwards, relatively narrower, thickened from basal third in R. sauditus ); pronotum with shallow and broader median groove, more densely covered with scales in its anterior half, and with granules less dense, scarcely distinct, scattered on surface and not conically raised, and elytra nearly completely without granules excepting a few near base, without short, semi-erect setae; larger white scales less dense, smaller yellow scales slightly broader and more frequent, forming a nearly uniform vestiture on sutural interval. Sternum VIII of female with arms weakly curved and moderately broadened, length/width ratio 2.30 (arms subangularly broadened, ratio 1.84–1.98 in R. sauditus ); hemisternites long, more sharply attenuated at apex; spermatheca with cornu more slender, narrower and more strongly curved. Aedeagus slightly broader, sides subangularly constricted before apical lamella. All other species of Rhabdorrhynchus , none of which have ever been recorded for the Arabian Peninsula, are larger, and usually have a much sparser elytral vestiture, with larger white scales scattered in small patches and the rostrum more distinctly grooved basally, before the vertex. P. efflatouni ( Tewfik, 1942) , from Yemen, Wadi Sharis, according to its description, is apparently quite close to some species from sub-Saharan Africa and is characterized by the presence of bifid or digitate scales, the pronotum lacking isolate granules and with a broad median impression, and the elytra having glossy black spots.

Figures

Figures 16–30. Rhabdorrhynchus emir, holotype ♀. Body, dorsal view (16); lateral view (17). Ventrites (18). Elytra (19). Rostrum, dorsal view (20); lateral view (25). Pronotum (21). Antenna (22). Sternite VIII (23). Spermatheca (24). Ovipositor (26). Paratype ♂. Aedeagus, median lobe, dorsal view (29); lateral view (30); detail of median lobe (28) and apex (27). Scale bars: 16 and 17, 5 mm; 18, 2 mm; 19–21 and 25, 1 mm; 22, 23, 26, 28–30, 0.5 mm; 24 and 27, 0.2 mm.