Trigonopterus vossi

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 : 43-48

Trigonopterus vossi nom.n.

Mimidotasia submetallica Voss, 1960: 328 -329. Type locality: New Guinea, probably Friedrich Wilhelmshafen (= Madang), possibly Berlinhafen (= Aitape).

Trigonopterus submetallicus (Voss) , comb.n.

nec Trigonopterus submetallicus Marshall, 1921: 590 . (secondary homonymy)

( Figs. 142–159 )

Diagnosis. Body ( Fig. 142 ) black, densely punctate, microreticulate, dull, with sparsely scattered white scales. Elytron with intervals carinate, apex broadly truncate. Metafemur without stridulatory patch. Sternite VIII ( Fig. 150 ) narrow, sternite IX ( Fig. 151 ) forming large exposed “V”. Aedeagus ( Figs. 148–149, 152–153 ) with asymmetrical apex, right side with long bifurcate process.

Description. Holotype, female ( Figs. 142–147 , 155–159 ). Length. Pronotum + elytra 2.2 mm.

Color black with weak bronze-greenish lustre; rostrum, antenna and tarsi ferruginous; body with sparsely scattered white scales. Integument of elytra and pronotum markedly sculptured.

Habitus subovate with marked constriction between prothorax and elytra; profile dorsally with constriction between pronotum and elytron. In thanatosis ( Fig. 147 ) legs sticking out from horizontal body plane at ca. 70°; dorsal edge of metafemur distant from elytral edge; tibiae largely left exposed; gaps between legs distinct, especially at base.

Rostrum ( Fig. 143 ) ca. 2.0 X as long as wide at base, widest basally and subapically, sides concave; in profile evenly convex; dorsal surface basally well behind antennal insertion with short median ridge and pair of submedian ridges; anteriorly sculpture shallow, shiny, weakly punctate-rugose; epistome indistinct, simple, apically with few long setae.

Head. Fig. 143 . Eyes subovate, not fully concealed by pronotum when in thanatosis position; dorsal margin bordered by distinct furrow. Forehead between eyes slightly narrower than rostral base (0.9 X), irregularly punctate-rugose, vertex behind eyes glabrous.

Antenna inserted somewhat behind middle of rostrum. Scape subequal to article 1 – 3 of funicle, fully concealed in rostral channel in thanatosis position.

Pronotum 1.47 X wider than long, widest in posterior third; sides rounded to shallow subapical constriction; anterior margin convex, posterior margin subtruncate; disc densely deeply punctate-rugose; each puncture containing one subrecumbent claviform white scale; scales wider along midline and laterally, sublaterally narrower; along submedian line with 9 punctures; interspaces between punctures subequal to or narrower than puncture´s diameter, glabrous, confluent forming longitudinal wrinkles; disc smoothly rounded towards sides; weak postocular lobe separated by shallow constriction from straight profile of marginal carina, antecoxal projection of marginal carina angulate, directed ventrad; side above procoxa simple, punctate, without fovea.

Elytra amphora-shaped, basally truncate, 1.16 X longer than wide, 1.41 X wider than base of pronotum, widest in basal 0.32 of elytral length; in profile dorsally smoothly convex, 0.63 X as deep as long; striae deeply impressed, each puncture bearing narrow white recumbent scale; intervals carinate, subglabrous, coriaceous, dull; at base and near humerus simple; interval 7 subapically swollen, forming transverse process; elytral apex broadly truncate.

Thoracic venter. Fig. 145 . Procoxa anteriorly punctate, punctures each containing recumbent seta; subapically with tooth; mesal face subglabrous, without punctures. Ventral setose fringe of hypomeron forming indistinct receptacle brush; modified setae medially slightly longer than later ones. Mesothoracic receptacle broadly U to Vshaped; ventrally produced beyond level of coxal apices; posteriorly steeply declivous, microreticulate, dull, hind wall with pair of deep foveae containing each 1 narrow scales; ventral rim with recumbent scales. Mesocoxa simple, without tooth. Metaventrite medially shorter (0.8 X) than exposed part of mesoventrite, disc broadly concave, coriaceous, dull, with sparse deep punctures; lateral intercoxal ridge weakly protruding ventrad, dentiform, in lateral aspect triangular; anterior rim of metacoxal cavity without secondary denticle. Sides of metaventrite irregularly sculptured, with few large punctures, dorsally with costa along deeply impressed epipleural suture. Metacoxa in mesal angle with oblique ridge, without seta.

Legs. Femora moderately compressed laterally, weakly clavate; anterior surface weakly microreticulate, weakly shining, in basal half sparsely punctate, in apical half densely deeply punctate, punctures containing each one recumbent white seta; anteroventral furrow indistinct, containing row of narrow scales; with indistinct anteroventral ridge; posteroventral ridge absent; without ventral teeth. Profemur posteriorly microreticulate, dull, densely punctate-rugose. Mesofemur posteriorly microreticulate, dull, sparsely punctate; subapically with sparse white recumbent scales. Metafemur subapically distinctly bent ventrad, in repose not reaching elytral apex; posterior surface microreticulate, dull, with one row of punctures along ventral edge; subapical posterior surface without stridulatory patch; dorsoposterior edge with distinct row of ca. 6 denticles, with sparse coverage of white recumbent scales; suture with trochanter oblique with ventral edge. Tibiae with fine longitudinal ridges bordered by rows of dorsad pointing setae; dorsal edges of protibia simple, meso- and metatibia in basal half with sparse distinct denticles; apex with uncus, without premucro. Anterior setose comb of metatibia subapically following midline of metatibia from base of uncus. Tarsi with tarsomere 3 subovate, shape of apical lobes symmetrical; tarsomere 3 ca. 2 X as wide as tarsomere 2, 1.7 X longer than tarsomere 2; claw-segment inserted at center of tarsomere 3; tarsomere 5 relatively long, 1.3 X as long as tarsomere 3; tarsal claws minute.

Abdomen. Ventrites dull, posterior ones weakly microreticulate. Ventrite 1 anteriorly slightly above level of metacoxae, with deep punctures, posteriorly markedly sloping dorsad, impunctate. Ventrites 2-5 dorsal of elytral margin. Suture between ventrites 1–2 effaced. Ventrite 2 laterally with pair of short transverse impressions. Ventrites 2-4 subglabrous. Ventrites 3–4 of equal length, relatively wide, flat. Ventrite 5 almost flat, sublaterally with pair of shallow impressions, subapically sparsely setose, far retracted into elytra.

Terminalia ( Figs. 155–159 ). Tergite VIII ( Fig. 159 ) as long as wide, spatulate, apical tip extended, weakly rounded, simple, not crenulate. Sternite VIII ( Fig. 156 ) with apical plate subrotund, apex rounded, medially with small membranous notch, sparsely setose. Coxite ( Fig. 157 ) without conspicuous setae, 3.8 X as long as stylus. Stylus ( Fig. 157 ) subcylindrical, straight, apically with stiff setae. Bursa copulatrix ( Fig. 155 ) membranous, without sclerites; ductus spermathecae weakly sclerotized. Spermatheca ( Fig. 158 ) apically with relatively wide lumen; apical 1/5 solid chitinous.

Paralectotype, male. Same as lectotype except: Length. Pronotum + elytra 2.14 mm. Rostrum dorsally with distinct median ridge and pair of similar submedian ridges, sulci between ridges containing each one row squamiferous punctures, linear scales directed mesad; ridges flattening in apical 1/3; epistome simple, without tooth, cuticle shining, sculpture shallow, apically with sparse row of setae. Thoracic venter. Mesothoracic receptacle ventrally produced to level of coxal apices. Disc of metaventrite deeply concave, forming common concavity with abdominal ventrite 1. Abdomen. Apex of ventrite 5 double-folded with a smooth thin dorsal plate originating on dorsal surface of ventrite 5; apex of true ventrite 5 slightly shortened, with sparse setae; dorsal process of ventrite 5 narrow crescent-shaped, glabrous, smooth, closing with elytral margin. Terminalia. Figs. 148–154 . Sternite VIII ( Fig. 150 ) narrow, ca. 5 X as wide as long; apically with angulate notch, sublaterally sparsely setose; sides markedly converging to apex. Sternite IX ( Fig. 151 ) weakly curved to the right, in apical 1/3 arms forming wide “V”, largely exposed. Tegmen ( Fig. 154 ) Y-shaped, apodeme short, dorsal portion of ring absent. Aedeagus ( Figs. 148–149, 152–153 ) slender; with sides of body subparallel, apex markedly asymmetrical, right side with long bifurcate process, right branch relatively short and rounded, right branch long and slightly pointed; ventral margin of basal orifice extended apicad; subglabrous, dorsal surface and apex subglabrous, without setae; ostium with obliquely transverse folded sclerites; endophallus with one curved asymmetrical sclerite at middle of aedeagal body; apodemes ca. 0.7 X as long as aedeagal body; transfer apparatus entirely contained within aedeagal body, symmetrical, but slightly tilted to right side, base of ductus ejaculatorius held by pair of crescent-shaped sclerites, extended into short basad pointing tooth; ductus ejaculatorius ca. 1.5 X as long as aedeagus, internally strongly sclerotized, basally where leaving basal orifice relatively thin, more apically slightly swollen (weak “bulbus ejaculatorius”).

Material examined. Type specimens: Holotype, female: PAPUA NEW GUINEA: Madang; labels (fig. 146): 1) [rectangular, white] “Friedrich-Wilh.-hafen [printed]” 2) [rectangular, white] “N. Guinea, Biró 96 [printed]” 3) [rectangular, white] “male gender symbol [hand-written]” 4) [rectangular, white with red margin] “ Holotypus [printed] 1960, Mimidotasia submetallica Voss ” ( HNHM). Paratypes: PAPUA NEW GUINEA: Madang: 1 male, 1 female, same data as holotype; East Sepik Prov.: 1 female, Tamara, Berlinhafen [Aitape], leg. Biró ( ZMH).

Notes. Contrary to his usual habit Voss (1960) explicitly designated a holotype. Although he stated that two male specimens belong to the type series of six specimens he chose a female. It was possible to examine four type specimens: three from HNHM, and one paratype from Voss´s private collection deposited at ZMH. The whereabouts of the remaining two specimens are unknown. One of the specimens of HNHM is labeled “ Holotype ”, two of them “ Paratype ”, but these are not the original labels of Voss, but the ones of the curator Z. Kaszab. The specimen labeled as holotype is a female, which is consistent with the original description, but it bears a small label with a male gender symbol. The three specimens from HNHM are from “Friedrich-Wilh.-hafen” which is equivalent to today´s Madang. The single specimen from ZMH is labeled “ Paratypus ”; it is marked with a male gender symbol, although in fact it is a female. It comes from “Tamara, Berlinhafen”, equivalent to the region of Aitape, about 450 km to the Northwest. It is slightly smaller than the specimens from Madang but matches them in other external characters. All in all, the situation is confusing: Voss has fixed a holotype. Two specimens of the type series are missing. The specimen labeled “ Holotype ” by Z. Kaszab may be the real holotype, or it may be just a paratype. The type series contains specimens from two distant populations that may represent the same species, or, possibly different ones. Males from the Aitape-population need to be examined for clarification. Voss (1960) did not state from which locality the holotype comes. Until one or both of the two remaining specimens of the type series are rediscovered and the contrary is proven we can only believe that Kaszab´s Holotype-labeling was correct.

Trigonopterus vossi is most likely the sister species of species 63 ( ARC 0858, ARC 0859, ARC 0883), an undescribed species from Biak Island, which is similar in habitus and aedeagus. Both share the peculiar morphology of the male ventrite 5 with a double-folded apex and the morphology of male sternites VIII-IX with T. oblitus .

Figures

FIGURES 142 – 147. Trigonopterus vossi; holotype: (142) dorsal aspect; (143) frontal aspect; (144) lateral aspect; (145) ventral aspect; (146) labels; (147) thanatosis position, lateral aspect.

FIGURES 148 – 154. Male terminalia of Trigonopterus vossi, paralectotype: (148, 149) aedeagus, lateral aspect; (149, 153) aedeagus, dorsal aspect; (150 – 151) sternite VIII – IX; (154) tegmen.

FIGURES 155 – 159. Female terminalia of Trigonopterus vossi, holotype. (155) overview; (156) sternite VIII; (157) coxite; (158) spermatheca; (159) tergite VIII.