Rhabdorrhynchus sauditus, Meregalli, 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 : 27-31

RHABDORRHYNCHUS SAUDITUS SP. NOV.

Type locality: Saudi Arabia, As Shāqqah al Yamānīyah, 19°42′N, 40°48′E .

Holotype ♀, Saudi Arabia: Saudi Arabia, Shagi Yamani , 40 m [iles] south of Lith [= As Shâqqah al Yamânîyah, about 50 miles south of Lith, 19°42′N, 40°48′E], 28 March 1948, B. P. Uvarov ( BMNH).

Paratypes: same data as holotype, 3♂, 2♀ (1♂, 1♀, MER; 2♂, 1♀, BMNH) .

Diagnosis: A Rhabdorrhynchus of small size, characterized by the following features: pronotum convex, globose, granulose, at maximum width nearly as broad as elytra; rostrum flattened on dorsum, with distinct, roughly punctured dorsolateral keels, elytra elliptical, with dense vestiture of whitish scales; aedeagus slender, apex triangular; sternum VIII of female with arms joined at base; spermatheca with slender and curved cornu, thickened nodulus and distinct ramus.

Measurements: Body length including rostrum, 8.40– 9.79 mm. Rostrum: length 1.60–1.86 mm, width 0.90– 0.94 mm. Pronotum: length 2.51–3.08 mm, width 3.05–3.37 mm (ratio 0.85–0.93). Elytra: length 5.72– 6.09 mm, width 3.50–3.86 mm (ratio 1.55–1.63). Ratio of elytral to pronotal length, 1.98–2.28; ratio of elytral to pronotal width, 1.14–1.16.

Description: Body elliptical, barely convex in lateral view, integument moderately glossy, reddish on elytra, dark reddish on head, pronotum and legs; Rhabdorrhynchus Pachycerus

Rostrum: dorsolateral keels broad, irregular, very deeply sculptured and punctured; dorsum deeply sculptured, with very irregular punctures and granules, usually with at least a hint of a shallow transverse impression beyond head. Epistoma broad, triangular, well delimited posteriad by two oblique furrows, apex concave.

Antennae: segment 1 of funicle longer and barely broader than segment 2; basal third of segment 1 of club glossy, with sparse scales similar to those of the funicle, simulating a short eighth funicle segment ( Figs 37, 38, 41, 42 ).

Pronotum globose, often slightly convex in lateral view, with more or less dense granulation, dorsum with a median smooth line, often depressed in a shallow groove, usually covered with white glossy scales, in part interrupted by a median granule.

Scutellum small and narrow, distinct.

Elytra elongate, sides subparallel, maximum width near middle of length; vestiture not hiding integument, composed of small patches of white simple scales scattered on the surface, more or less dense, and occasionally with yellow narrow hair-like scales, more uniformly placed on the odd intervals; bifid scales absent or only present on underside of head and sternal segments.

Ventrites usually ‘irrorate’, with sparse slender scales leaving out bare scattered patches not well delimited and irregularly distributed.

Underside of segments 2 and 3 of the fore tarsi with a thick, complete pad of orange setae.

Apical field of wings as long as wide ( Figs 35, 36 ).

Blades of proventriculus short, chaetae nearly reaching base of the blade ( Figs 46, 47 ).

Sternite VIII of ♀ with arms U- or V-shaped, connected at base; sclerotization of apical plate moderate or limited to a small area around arms ( Fig. 44 ).

Spermatheca with narrow, curved cornu, usually acuminate at apex.

Hemisternites variable, but usually regularly constricted apicad ( Fig. 49 ).

Symbiont pouches not examined in all the species; those seen are shorter than the hemisternites, and are scarcely sclerotized.

Rostrum: dorsolateral keels straight, usually sharp, narrow, not punctured, dorsum with dense, shallow and more regular punctation, with a broad triangular raised plate, widened forwards, or with a narrow median keel, lacking a basal transverse impression. Epistoma small, scarcely delimited posteriad, apex straight or convex in median part.

Antennae: segment 1 of funicle globose, narrowed near insertion to scape, broadened at suture with segment 2 and distinctly wider than segment 2; segment 1 of club also regularly hairy at base in most species, or with a barely distinct glossy part ( Figs 39, 40 ).

Pronotum flattened on dorsum, irregularly sculptured, with few, sparse granules; disc often with a shallow and broad, irregularly rhomboidal impression, median part flat or, mainly anteriad, with a narrow raised keel, lacking a groove with white scales.

Scutellum not visible, or very minute.

Elytra ovate–elliptical, sides weakly converging from base to apex, maximum width shortly behind humeri; vestiture more or less dense above most of the surface, composed of simple or often bifid scales, sometimes leaving out two irregular patches on median part on intervals 3–7.

Ventrites densely coated with simple or, usually, bifid scales, leaving out bare round patches, well delimited and symmetrically placed.

Underside of segments 2 and 3 of the fore tarsi variable, often with a reduced pad.

Apical field of wings longer than wide, minor differences in the veins are also detectable ( Fig. 34 ).

Blades of proventriculus very elongate, chaetae only present in their apical half ( Fig. 45 ).

Sternite VIII of ♀ with arms connected at mid length, apodeme long to very long, sometimes nearly as long as the apical plate, arms usually widened; apical plate often in large part, or completely, sclerotized ( Fig. 43 ).

Spermatheca with broad, moderately curved cornu, not acuminate at apex.

Hemisternites always very broad, sharply constricted apicad ( Fig. 48 ).

Symbiont pouches elongate, sometimes longer than the hemisternites. vestiture composed of dense, white, elliptical, glossy, simple scales and narrow, hair-like, yellowish scales, with bifid scales only present on underside of head ( Figs 1, 5 ).

Rostrum subquadrate in cross section, in lateral view nearly straight from base to antennal insertion, slightly curved and thickened at apex. Surface roughly sculptured, with two dorsolateral, broad, glossy keels, higher and converging at their base on vertex, not touching eyes, irregularly delimited and slightly divergent anteriad, punctured on their inner side, joined to upper margin of scrobe above antennal insertion, and extended up to apex; in lateral view keels high, convex above eyes, slightly sinuate downwards at middle of rostrum length, raised again above antennal insertion, narrowed and sharpened towards apex, in some specimens only distinct and glossy in the basal part, between the eyes, shallower anteriad and forming densely punctured raised dorsolateral margins, not extending to apex. Dorsum of rostrum flat, densely and deeply sculptured, with wrinkles and punctures, median part forming an irregular subtriangular plate, broadened anteriad, separate from the dorsolateral keels by two narrow, moderately impressed furrows, flattened at antennal insertion, and directed laterally around epistoma at apex. Apex curved downwards, epistoma semicircular, well delimited, flat, broadly punctured, and nearly matt, concave at apex. Lateral sides, delimited by the expanded upper margin of scrobes and the dorsolateral keels, partly visible from above, triangular, broadened basad. Vestiture: sparse hair-like scales inserted in the wrinkles and punctures on the dorsolateral keels and sides; larger, denser, glossy, white scales on the median part, covering integument. Scrobes curved, deep; upper margin thickened, expanded outwards, fully visible from above, in lateral view distinctly convex and densely punctured above antennal insertion, smooth, more glossy behind, curved towards base of eyes; lower margin short, subparallel to upper margin, curved downwards ( Figs 3, 8 ). Antennae inserted at three-quarters of rostrum length; scape slightly curved forwards, regularly thickened from basal third; funicle as thick as scape at apex, segment 1 subconical, 1.3 times longer than broad; segment 2 subquadrate, half as long as segment 1; segments 3–7 transverse, 3rd very short, 7th slightly broader; club large, elliptical; scape and funicle with dense white scales and some slightly longer white setae; club elliptical, basal part of segment 1 glossy and with some smaller white scales, simulating an eighth segment of funicle; remaining part of club silvery hairy ( Figs 4 , 38, 41 ).

Head short, transverse; vertex flat, roughly punctured; interocular pit distinct; eyes large, moderately convex, reaching upper side of head, their upper half visible from above, interocular distance on head three-quarters as wide as rostrum at its maximum width between upper margins of scrobes; in lateral view eyes elongate, moderately narrowed in their lower part, lower margin rounded. Vestiture: white scales around eyes, mainly on upper part; hair-like scales on sides; short, bifid scales connate near base on underside.

Pronotum large, as long as broad, dorsum slightly convex in lateral view, globose, base medially slightly expanded towards scutellum, not acutely prominent; sides moderately and regularly rounded from base to near apex, slightly more convergent apicad; apex curved on middle, prominent above head, nearly straight on sides, ocular lobes barely distinct, with a fringe of long and thick light-yellowish setae. Dorsum with a narrow, relatively deep median groove, narrowed on its middle and with a cleft granule or with a thin median carinula, which can be larger and more raised in the centre; surface with dense granules, irregularly placed, conically raised near base and sides, slightly flattened on top of disc; interspaces between the granules matt, microsculptured, forming short irregular rows; sides with conical granules prominent when seen from above. Vestiture: very short, barely distinct hair-like scales sparse on dorsum, longer and more dense on the posterior part of the upper half of sides; larger white scales on the anterior part of the median groove and the anterior part of sides, extended to base in the lower part of sides ( Fig. 2 ).

Scutellum narrow, triangular, bare.

Elytra elongate-elliptical, at base as wide as base of pronotum, sides subparallel, slightly narrowed behind humeri, in lateral view depressed, gently declivous, barely sloping. Apex of each elytron with a short acute projection. Surface unevenly and deeply wrinkled, with sparse small glossy granules clearly visible above the white scales of the vestiture, denser on basal half, in some specimens extending for the whole length along suture and the odd intervals, sparse and smaller on the even intervals; intervals flat, base of intervals 3 and 5 slightly raised; odd intervals as wide as even ones, clearly delimited only in apical half of elytra; striae on basal half with shallow, irregularly impressed punctures, much wider than intervals at base, narrowing in posterior half to form grooves distinctly narrower than intervals towards apex. Vestiture: larger white scales forming a thick coating that covers surface, continuous and rather uniform on sutural interval, but arranged in several large patches on rest of elytra, except for small sparse uncoated spots and two larger irregular bare patches on intervals 2–5 behind middle of length; hair-like yellow scales scattered over whole surface, not covering integument, usually denser on even intervals and on the part of the surface devoid of larger scales, including part of the large bare patch on interval 4; short, white setae similar to the larger scales obliquely inserted on the granules; base lacking scales or setae ( Fig. 7 ).

Prosternum smooth, space between anterior margin of fore coxae and apex as long as diameter of fore coxae; metasternum longer than diameter of middle coxae. Ventrite I as long as ventrite II, weakly convex in middle in female, flattened and with a narrow median impression in male; ventrites III and IV less than half as long as II, slightly convex, ventrite V short, transverse. Vestiture: larger white scales forming a thick, uniform coating, delimiting round bare patches; on ventrites I and II, four lateral and two median, closely approached patches; on ventrite II, the two outer patches smaller; on ventrites III and IV, the two outer patches absent and the median ones merged; on ventrite V, a bare irregular median line on basal half ( Fig. 6 ).

Legs slender, femora scarcely thickened in middle; fore tibiae elongate, inner side weakly sinuate, inner preapical teeth moderately developed in female, barely distinct in male, apex moderately broadened, with about ten short yellowish apical denticles, uncus strong; middle and hind tibiae slender, cylindrical; tarsal segments as long as broad, segment 3 with scarcely widened lobes ( Fig. 32 ); underside of each segment with fringe of orange setae limited to lateral margins; onychium nearly as long as segments 1–3, claws robust. Vestiture: thick coating of white scales on the whole surface, including tarsi; longer white semi-erect setae on inner side of tibiae, particularly middle and hind, and on tarsi.

Aedeagus slender, median lobe weakly curved, apical lamella triangular, shortly acutely pointed ( Figs 11, 13–15 )

Spiculum gastrale narrow, slender, weakly curved.

Proventriculus with short blades, chaetae not extended towards pharynx ( Fig. 46 ).

Hemisternites broadened basad, gradually tapering towards apex; styli subquadrate, short, apical ( Fig. 9 ); symbiont pouches short, compact, globose; spermatheca with long and narrow, acutely pointed curved cornu, subquadrate ramus, and thickened nodulus ( Fig. 10 ). Sternum VIII with thin arms joined at base and broadly widened, sclerotized plate nearly absent, limited to a small area around apex of arms ( Fig. 12 ).

Variation: The holotype is the largest specimen; size varies from 8.40 to 9.79 mm, but most of the paratypes are only very slightly smaller than the holotype. Variation among the six specimens examined is mainly evident in the rostrum, which can have the dorsolateral keels, strongly developed, higher and glossy, as in the holotype, or only distinct and glossy in the basal part, between the eyes and shallower, less distinct anteriad, and forming densely punctured raised dorsolateral margins, not extending to apex; the granules on the pronotum are always very dense and conical, but sometimes more irregularly distributed; the narrow median groove of the pronotum can be nearly completely interrupted by a granule in the centre or can show a very thin median carinula, which can be larger and more raised in the centre. The elytral shape and vestiture are very uniform, but in some specimens the small glossy granules are nearly exclusively limited to the basal part; the ratio of elytral to pronotal width is very constant, whereas the ratio of elytral to pronotal length is more variable. The female genitalia are very constant, with the arms of the sternite VIII typically subangulate laterally.

Etymology: Named after the country of origin, Saudi Arabia.

Distribution: The type locality is south of Lith, in the central part of the Saudi Arabian coast of the Red Sea.

Figures

Figures 31–49. Rhabdorrhynchus menetriesi, Anatolia, Kaptanmaras¸, ♂. Hind tarsus (33). Hind wing (36). Scape and first segments of antenna (37). Segment 7 of antenna and club (42). Blade of proventriculus (47). Rhabdorrhynchus karelini, Kyrgyzstan, Issyk-Kul, ♀. Sternite VIII (44); ovipositor (49). Pachycerus segnis, Anatolia, Izmir, ♀. Hind tarsus (31). Hind wing (34). Scape and first segments of antenna (39). Segment 7 of antenna and club (40). Blade of proventriculus (45). Sternite VIII (43). Ovipositor (48). Rhabdorrhynchus sauditus, holotypus ♀. hind tarsus (32). Hind wing (35). Scape and first segments of antenna (38). Segment 7 of antenna and club (41). Blade of proventriculus (46). Scale bars: 34–36, 2 mm;31–33, 1 mm; 37–39 and 43–49, 0.5 mm; 40–42, 0.2 mm.

Figures 1–15. Rhabdorrhynchus sauditus, holotype ♀. Body, dorsal view (1); lateral view (5). Ventrites (6). Elytra (7). Rostrum, dorsal view (3); lateral view (8). Pronotum (2). Antenna (4). Sternite VIII (12). Spermatheca (10). Ovipositor (9). Paratype ♂. Aedeagus, median lobe, dorsal view (15); lateral view (11); detail of median lobe (14), and apex (13). Scale bars:1–5, 5 mm;6 and 7, 2 mm; 2–4 and 8, 1 mm; 9–12, 14 and 15, 0.5 mm; 10 and 13, 0.2 mm.