Trigonopterus insignis Fauvel

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 : 20-24

Trigonopterus insignis Fauvel

Trigonopterus insignis Fauvel, 1862: 158 –159.

( Figs. 60–71 )

Diagnosis. Body ( Fig. 60 ) pear-shaped, black, partly coriaceous. Eyes ( Fig. 61 ) medially approximate. Disc of pronotum densely deeply punctate, medially punctures longitudinally confluent. Elytra of subtriangular shape; near humerus elytral stria 9 with 4 punctures of decreasing size laterally bordered by distinct ridge. Dorsoposterior edge of metafemur covered with white suberect scales; metafemur subapically without stridulatory patch. Aedeagus ( Figs. 70–71 ) dorsally at middle with pair of oblique combs of long setae.

Description. Holotype, male ( Figs. 60–71 ). Length. Pronotum + elytra 3.3 mm. Color entirely black. Integument of elytra and pronotum polished, punctate, nude except setae contained in punctures; legs, procoxa and rostrum with sparse whitish scales not concealing the cuticle.

Habitus pear-shaped, with distinct constriction between prothorax and elytra; body in profile dorsally evenly convex. In thanatosis ( Fig. 65 ) legs sticking out from horizontal body plane at ca. 80°; dorsal edge of metafemur distant from elytral edge; tibiae largely left exposed; gaps between legs distinct, especially at base.

Rostrum ( Figs. 61–62 ) ca. 3.0 X as long as wide at base, near antennal insertion with very shallow constriction, evenly curved ventrad; in profile dorsal contour convex, ventral contour weakly concave; dorsally with distinct median ridge and pair of similar submedian ridges, sulci between ridges containing each one row of mesally directed suberect scales; ridges flattening subapically; epistome simple, without tooth, cuticle shining, with scattered setae.

Head. Eyes subrotund, medially approximate, 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), markedly punctate-rugose, narrow interspaces microreticulate; vertex behind eyes densely regularly punctate.

Antenna inserted slightly behind middle of rostrum. Scape short, subequal to article 1 + 2 of funicle, fully concealed in rostral channel in thanatosis position. Left antenna missing; club and funicle of right antenna missing except first two articles of funicle.

Pronotum 1.22 X wider than long, widest at middle, sides weakly diverging to middle, rounded to apex, without subapical constriction; anterior and posterior margins subtruncate; disc densely deeply punctate, punctures becoming ovate towards middle, partly joining as longitudinal rugae; each puncture containing one erect seta subequal in length to puncture´s diameter; narrow midline impunctate except near base and apex; along submedian line with 14 punctures; interspaces between punctures usually narrower than puncture´s diameter, weakly microreticulate; disc separated from sides by rounded edges of alveolate sculpture; sides below less densely punctate; postocular lobe rounded, separated by constriction from convex profile of marginal carina, antecoxal projection of marginal carina distinct, subacute, directed ventrad; side above procoxa simple, without fovea.

Elytra of subtriangular shape, basally truncate, 1.35 X longer than wide, slightly wider (1.11 X) than base of pronotum, widest in basal 0.14 of elytral length; profile dorsally smoothly convex except basally with weak depression, 0.63 X as deep as long; striae marked by thin hairline impressions and rows of small punctures; flat intervals dull to weakly shiny, coriaceous, with sparse minute punctures, partly microreticulate, especially along striae and laterally; basal margin costate, bordered by transverse row of large punctures; stria 9 basally near humerus with 4 closely-knit punctures of decreasing size laterally bordered by distinct ridge, subapically entrenched as furrow containing few indistinct punctures; suture at elytral apex weakly incised, elytra individually rounded.

Thoracic venter. Fig. 63 . Procoxa anteriorly and apically punctate, with sparse suberect scales, posteroapically with blunt tooth, mesal face subglabrous, without row of punctures or foveae. Ventral setose fringe of pronotal hypomeron forming distinct but relatively short receptacle brush; modified setae medially longer than lateral setae. Mesothoracic receptacle relatively shallow, anterior margin concave; ventrally produced markedly beyond level of mesocoxal apex; posteriorly microreticulate, dull, with pair of broad pits containing each three erect scales; ventral rim with sparse suberect scales. Mesocoxa mesally punctate, with scattered suberect scales, without distinct teeth. Metaventrite medially 1.1 X longer than exposed part of mesoventrite, disc broadly concave, punctate, microreticulate, dull, each puncture with one erect scale; lateral intercoxal ridge weakly protruding ventrad, in lateral aspect ventrally transversely truncate; edge hanging from anterolaterally over anterior portion of metacoxa; anterior rim of metacoxal cavity near mesal angle of coxa with angular protrusion. Sides of metaventrite alveolate, above with two deep craters almost reaching to epipleural suture, without ventral costa. Metacoxa in mesal angle with three long setae; simple, without tooth.

Legs. Femora moderately compressed laterally; pro-, meso- and metafemur of similar size, elongate, weakly clavate. Anterior surface weakly microreticulate, densely punctate with deep punctures containing each one short white scale, punctures becoming denser apically; anteroventral furrow deep, containing fringe of long scales. Profemur with distinct anteroventral ridge abruptly terminating 1/3 from apex forming blunt tooth, subapically outline slightly concave; posteriorly coarsely rugose-punctate; punctures containing suberect setae; basally bordering trochanter with subglabrous pit; posteroventral ridge in apical half distinct, basally indistinct; dorsally subglabrous, without scaling, with sparse small punctures, subapically with few large punctures. Mesofemur and metafemur with indistinct anteroventral ridge, posteroventral ridge more distinct; without ventral teeth. Mesofemur dorsally with one inconspicuous row of small recumbent scales; posterior surface partly subglabrous, bordering posteroventral ridge with furrow containing row of squamiferous punctures, more dorsally with additional row of deep punctures. Metafemur in repose not reaching elytral apex, posterior surface partly subglabrous, bordering posteroventral ridge with furrow containing row of squamiferous punctures, more dorsally with additional row of deep punctures; subapically without stridulatory patch; dorsoposterior edge with indistinct row of rounded denticles, covered by white suberect scales; suture with trochanter oblique with ventral edge. Tibiae with fine longitudinal ridges bordered by rows of dorsad pointing setae; dorsal edges simple, without denticles; apex without premucro. Anterior setose comb of metatibia subapically transverse-oblique from base of uncus approaching dorsal margin. 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 behind metacoxa with dentiform protrusion. Ventrites 1 and 2 forming common concavity, densely punctate with deep punctures bearing each one upcurved scale, interspaces between punctures narrow and microreticulate; suture between ventrites 1-2 distinct throughout. Ventrites 3-4 narrow, of equal length, each with one transverse row of setiferous punctures. Ventrite 5 medially with subglabrous, microreticulate concavity, posteriorly bordered by apical costa, anteriorly open; laterally densely punctate with large squamiferous punctures; apex simple, not crenulate.

Terminalia. Sternite VIII ( Fig. 69 ) with sides converging; apex medially incised, with pair of rounded, setose lobes; at base 1.8 X wider than long. Sternite IX ( Fig. 69 ) straight; apical arms forming “V”, apically slightly widening, half covered by sternite VIII. Tegmen ( Fig. 68 ) with complete, slender ring, apodeme relatively long, parameroid lobes distinct, medially approximate, apically with microchaetae. Aedeagus ( Figs. 66–67, 70–71 ) with sides subparallel, when viewed vertically in convex line converging to apex, medially extended into short acute tip; dorsal surface at middle with pair of oblique combs of long setae; in apical half laterally with sparse row of setae; near apical tip with short setae; in apical half with distinct sclerites; apodemes apically broken, tips missing; transfer apparatus compact, cup-shaped, near basal orifice, with stout hook-shaped appendix contained in aedeagal body, hook curving to the left; ductus ejaculatorius broken and apical portion missing; at least as long as aedeagus, internally strongly sclerotized.

Material examined. Type specimens. Male, holotype: NEW CALEDONIA. Labels ( Fig. 64 ): 1) [white, rectangular, 1 black line] [empty]” 2) [rectangular, red, black margin] “ Typus [printed]” 3) [rectangular, green] “Naturhistoriska Riksmuseet Stockholm Loan no 659/00 [printed]” 5) [rectangular, pink] “ Holotype, Trigonopterus insignis Fauv. , 0 5 Rheinheimer des. [hand-written]” 6) [rectangular, green] “Naturhistoriska Riksmuseet Stockholm Loan no 393/06 [printed]” ( NHRS).

Distribution. New Caledonia: precise locality uncertain.

Notes. Fauvel (1862) mentions the existence of only one single specimen, implicitly fixing a holotype.

Figures

FIGURES 60 – 65. Trigonopterus insignis, holotype: (60) dorsal aspect; (61) frontal aspect; (62) lateral aspect; (63) ventral aspect; (64) labels; (65) thanatosis position, lateral aspect.

FIGURES 66 – 71. Male terminalia of Trigonopterus insignis, holotype: (66, 70) aedeagus, lateral aspect; (67, 71) aedeagus, dorsal aspect; (68) tegmen; (69) sternite VIII – IX.