Trigonopterus inclusus (Pascoe)

Riedel, Alexander, 2011, The weevil genus Trigonopterus Fauvel (Coleoptera, Curculionidae) and its synonyms — a taxonomic study on the species tied to its genus-group names, Zootaxa 2977, pp. 1-49 : 16-20

Trigonopterus inclusus (Pascoe)

Idotasia inclusa Pascoe, 1871: 262 .

( Figs. 46–59 )

Diagnosis. Body ( Figs. 46–47 ) subovate, black, polished, densely punctate. Basal 2/3 of rostrum with marked dorsal protrusion, covered with grey upcurved scales; sides with deep secondary scrobe. Disc of pronotum longitudinally rugose. Metafemur dorsally covered with white scales, subapically with stridulatory patch. Aedeagus ( Figs. 54, 58 ) apically with deep median U-shaped incision; transfer apparatus consisting of spear-shaped piece and round sclerotized capsule basal of aedeagal body.

Description. Lectotype, male ( Figs. 46–59 ). Length. Pronotum + elytra 2.2 mm.

Color black, antenna and tarsi ferruginous. Integument of elytra and pronotum polished; elytra punctate, nude; pronotum densely punctate-rugose, sparsely setose; legs somewhat microreticulate, punctate, each puncture containing inconspicuous white recumbent scale; dorsal edge of mesofemur with sparse row of recumbent white scales; dorsal edge of metafemur covered with upcurved silvery-grey scales; base of rostrum with yellowish-grey scales.

Habitus subovate to subrhomboid, almost without constriction between prothorax and elytra; body in profile dorsally evenly convex. In thanatosis ( Fig. 52 ) legs forming compact unit, sticking out from horizontal body plane at ca. 60°; dorsal edge of metafemur distant from elytral edge; femora partly overlapping tibiae, partly left exposed; gaps between legs distinct, especially at base.

Rostrum ( Figs. 48, 50 ) ca. 1.7 X as long as wide at base, markedly curved ventrad; basal 2/3 with marked dorsal protrusion; in profile dorsal protrusion convex, in apical third contours of rostrum converging in straight line; dorsally scabrous, with distinct median ridge; basal protrusion with yellowish-grey upcurved scales directed mesally, hardly concealing the cuticle; laterally with deep secondary scrobe curving from above eye parallel to and above antennal scrobes to apical third of rostrum, deeply undercutting median dorsal protrusion; anterior quarter flattened, median costa disappearing, subglabrous, sculpture shallow, with sparse suberect setae; epistome simple, without tooth; in thanatosis, swollen basal half projecting beyond marginal carina of rostral canal.

Head. Eye subovate, only partly concealed by pronotum when in thanatosis position; dorsal margin bordered by distinct furrow. Forehead between eyes narrower than rostral base (0.7 X), punctate, punctures becoming smaller and sparse behind eyes.

Antenna inserted at middle of rostrum. Scape short, subequal to article 1 + 2 of funicle, fully concealed in rostral channel in thanatosis position.

Pronotum 1.69 X wider than long, widest at base, sides converging in straight line to apex, without subapical constriction; anterior margin bisinuate, posterior margin weakly convex; disc densely rugose-punctate, rugae consisting of 2-5 punctures joining in longitudinal direction, containing sparse setae; narrow midline impunctate; interspaces between punctures / rugae polished, smaller than puncture´s diameter, glabrous; smoothly rounded towards densely punctate sides; postocular lobe rounded, continuous with slightly sinuate profile of marginal carina, antecoxal projection of marginal carina distinct, subacute, directed ventrad; side above procoxa simple, without fovea. Elytra pyriform, basally truncate, apically slightly extended, 1.35 X longer than wide, 1.31 X wider than base of pronotum, widest in basal 0.29 of elytral length; profile dorsally smoothly convex, 0.65 X as deep as long; striae marked by row of small ovate punctures; flat intervals with row of similar punctures, resulting in confused punctation, subapically striae 1-2 deeply impressed for short distance; interspaces flat, glabrous, polished; basal margin simple, without transverse row of enlarged punctures; striae 8 and 9 indistinct, especially near humerus, intervals without any ridge; subapically stria 9 deeply entrenched, furrow containing dense row of punctures; suture at elytral apex weakly incised, elytra individually rounded.

Thoracic venter. Fig. 49 . Procoxa anteriorly punctate, apically with tooth and posteroapically with cluster of erect scales, mesal face subglabrous, at middle with row of 4 pits. Ventral setose fringe of pronotal hypomeron forming distinct receptacle brush; modified setae medially distinctly longer than lateral setae. Mesothoracic receptacle partly broken, rim splintered off at middle; broadly U-shaped with short side-walls; ventrally produced to level of mesocoxal apex; posteriorly subglabrous, microreticulate, dull, with pair of foveae, ventral rim of side walls with sparse white scales. Mesocoxa with scattered suberect scales, mesally with distinct tooth. Metaventrite medially 1.3 X longer than exposed part of mesoventrite, disc broadly concave, subglabrous, microreticulate, dull; lateral intercoxal ridge markedly protruding ventrad, in lateral aspect triangular, in ventral aspect intercoxal ridge oblique, its anterior end rotating distinctly mesad; posteriorly intercoxal ridge weakly extending over metacoxa; anterior rim of metacoxal cavity without secondary denticle. Sides of metaventrite glabrous, bordered by costa except dorsally where even with epipleuron; intercoxal ridge microreticulate, with few punctures. Metacoxa in mesal angle with few long, erect setae; mesoposteriorly with tooth.

Legs. Femora relatively long, moderately compressed laterally; with distinct but simple anteroventral ridge overlapping bent tibia; posteroventral ridge less marked but still distinct; without ventral teeth; anteroventral furrow distinct, bordered by fringe of narrow scales. Pro-, meso- and metafemur of similar size, elongate, sides subparallel, subapically weakly bent ventrad. Profemur anteriorly polished, punctate; posteriorly longitudinally strigulate, densely coarsely punctate; punctures containing inconspicuous scales; dorsally simple, without scaling. Mesofemur similar to profemur, but dorsally with rows of white scales not covering surface and indistinct row of denticles; posterior surface strigulate, sparsely punctate. Anteroventral ridge of meso- and metafemur slightly crenate. Metafemur in repose passing elytral apex, similar to pro- and mesofemur; anterior surface densely deeply punctate especially towards apex; posterior surface largely polished, with rows of deep punctures; subapical posterior surface with distinct stridulatory patch of transverse striation; basal limits of stridulatory patch ill-defined; dorsoposterior edge with distinct row of ca. 5 denticles, dorsal surface covered with white upcurved scales; suture with trochanter right-angled with ventral edge. Tibiae with fine longitudinal ridges bordered by rows of dorsad pointing setae; dorsal ridge of metatibia terminating in subapical tooth, apical portion of metatibia thus appearing narrower, bearing row of 4 erect scales; dorsal edge of protibia simple, meso- and metatibia in basal half weakly denticulate; apex with uncus and with indistinct premucro. Anterior setose comb of metatibia subapically following midline of metatibia from base of uncus. Tarsi with tarsomere 3 subtrapezoid, anteriorly markedly widened, shape of apical lobes symmetrical; tarsomere 3 ca. 2 X as wide as tarsomere 2, 1.3 X longer than tarsomere 2; claw-segment inserted at center of tarsomere 3; tarsomere 5 as long as tarsomere 3; tarsal claws minute.

Abdomen. Ventrite 1 flat, subglabrous, laterally behind metacoxae slightly swollen, strigulate. Ventrites 2 tilted slightly ventrad, flat, subglabrous; suture between ventrites 1-2 distinct throughout. Ventrites 3-4 narrow, of equal length, subglabrous. Ventrite 5 filled with bowl-shaped impression laterally and posteriorly defined by ridge, anteriorly open; bottom of impression subglabrous, near ridges punctate; apex simple, not crenulate.

Terminalia. Sternite VIII ( Figs. 55–56 ) subtrapezoid, sides converging to subtruncate apex, at base 2.0 X wider than long; laterally and towards base well-sclerotized, medially and towards apex weakly sclerotized; apex laterally setose. Sternite IX ( Fig. 56 ) straight, apical arms forming “V”. Tegmen ( Fig. 59 ) with complete, slender ring [broken in lectotype], apodeme relatively long, parameroid lobes missing. Aedeagus ( Figs. 53–54, 57–58 ); body with sides subparallel, apex with deep median U-shaped incision; dorsal surface sublaterally with rows of sparse short setae; membrane of ostium angulately folded, medially projecting over apical incision; with funnel-like endophallic sclerites; apodemes ca. 2.4 X as long as aedeagal body; transfer apparatus consisting of spear-shaped piece and round sclerotized capsule basal of aedeagal body providing guidance with basal opening; ductus ejaculatorius internally strongly sclerotized, apical portion broken and missing.

Material examined. Type specimens. Male, lectotype by present designation: INDONESIA, West Papua, Misool isl.; labels ( Fig. 51 ): 1) [blue, ovate] “Mysol [hand-written]” 2) [rectangular, white] “ Idotasia inclusa Pasc. , Type [hand-written]” 3) [rectangular, white with black margin] “ Idotasia inclusa Pasc. [hand-written]” 4) [rectangular, white] “Pascoe Coll. B.M.1893-60 [printed]” 5) [round, white with red margin] “ HOLOTYPE [printed]” 6) [rectangular, red] “ LECTOTYPE, Idotasia inclusa Pascoe , det A.Riedel 2010 [printed]” ( BMNH).

Distribution. INDONESIA, West Papua (Misool).

Notes. Pascoe (1871) did not designate a holotype in the original description nor specify the number of specimens examined. The round label stating “ Holotype ”, has subsequently been added by the staff of the BMNH. Other specimens may exist in addition to the specimen stored at the BMNH, which is considered a syntype and is here designated lectotype to ensure stability of nomenclature in case additional syntypes are discovered that belong to different species.

As indicated by the peculiar structure of the aedeagus with a deep median incision and the swollen rostral base this species is most closely related to T. ebriosus (Pascoe) from Salawatti Island. It can be separated by the puncaterugose sculpture of the pronotum and by the presence of an endophallic sclerite guiding the flagellum.

Figures

FIGURES 46 – 52. Trigonopterus inclusus, lectotype: (46) as originally mounted, dorsal aspect; (47) dorsal aspect; (48) frontal aspect; (49) ventral aspect; (50) lateral aspect; (51) labels; (52) thanatosis position, lateral aspect.

FIGURES 53 – 59. Male terminalia of Trigonopterus inclusus, lectotype: (53, 57) aedeagus, lateral aspect; (54, 58) aedeagus, dorsal aspect; (55 – 56) sternite VIII – IX; (59) tegmen.