Trigonopterus micros

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 : 24-29

Trigonopterus micros nom.n.

Microgymnapterus minutus Voss, 1960: 327 -328.

Trigonopterus minutus ( Voss, 1960: 327) , comb. n.

nec Trigonopterus minutus ( Voss, 1960: 341) , originally described as Idotasia minuta Voss.

( Figs. 72–88 )

Diagnosis. Body ( Fig. 72 ) small, 1.13-1.59 mm; densely punctate. Elytral striae deeply impressed, punctures bearing inconspicuous downcurved setae; intervals costate, glabrous, polished. Profemur longer than metafemur, most conspicuous in thanatosis (Fig. 77); metafemur without stridulatory patch. Tarsomere 5 long, claws relatively large. Aedeagus ( Figs. 78–79, 82–83 ).

Description. Lectotype, male ( Figs. 72–75 , 78–83 ). Length. Pronotum + elytra 1.32 mm.

Color deep ferruginous to black; ventral surface, antenna and tarsi lighter ferruginous. Integument of elytra and pronotum polished, markedly punctate, nude except small setae contained in punctures; legs, head and rostrum dull, very sparsely setose.

Habitus subovate, with marked constriction between prothorax and elytra; profile dorsally with constriction between pronotum and elytron. In thanatosis (as in fig. 77) 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. 73, 75 ) ca. 2.3 X as long as wide at base, widest basally and subapically, sides concave; in profile evenly weakly convex; dorsally punctate-rugose, with indistinct median ridge and pair of even less distinct submedian ridges; with very inconspicuous rows of mesally directed setae; epistome short, slightly swollen, without tooth, smooth, shining, apically with few long setae.

Head. Eyes subovate, not fully concealed by pronotum when in thanatosis position. Forehead between eyes narrower than rostral base (0.8 X), irregularly punctate-rugose.

Antenna inserted at middle of rostrum. Scape short, subequal to article 1 + 2 of funicle, mostly concealed in rostral channel in thanatosis position, very narrow region left exposed.

Pronotum 1.18 X wider than long, widest in posterior third; sides markedly rounded to shallow subapical constriction; anterior and posterior margins subtruncate; disc densely deeply punctate; each puncture containing one suberect seta; along submedian line with 8 punctures; interspaces between punctures subequal to puncture´s diameter, glabrous, shiny; disc smoothly rounded towards punctate sides; postocular lobe indistinct, separated by shallow constriction from convex profile of marginal carina, antecoxal projection of marginal carina distinct, angulate, directed ventrad; side above procoxa simple, without fovea.

Elytra of subtriangular shape, basally truncate, 1.18 X longer than wide, 1.22 X wider than base of pronotum, widest in basal 0.19 of elytral length; in profile dorsally smoothly convex, 0.59 X as deep as long; striae deeply impressed, punctures bearing short downcurved setae; intervals costate, glabrous, polished; punctures of similar size, at base and near humerus simple; elytral apex simple, jointly evenly rounded, not extended ventrad.

Thoracic venter. As in fig. 76. Procoxa anteriorly coriaceous, subapically with two teeth; mesal face subglabrous, at middle with few punctures. Ventral setose fringe of pronotal hypomeron without receptacle brush; medially with gap. Mesothoracic receptacle broadly V-shaped, medially with shallow constriction; ventrally produced slightly beyond level of coxal apices; posterior surface strigulate, dull, with weak median costa and pair shallow impressions; anterior edge with sparse minute scales. Mesocoxa simple, without tooth. Metaventrite medially slightly shorter (0.9 X) than exposed part of mesoventrite, disc broadly impressed, center flat, anteriorly with few setiferous punctures, strigulate, dull; 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, ventrally bordered by broad costa, anteriorly with narrow costa to epipleuron. Metacoxa in mesal angle with two long setae; without teeth.

Legs. Femora moderately compressed laterally. Profemur longer than meso- and metafemur, weakly clavate, slender. Meso- and metafemur short, apically markedly curved ventrad. Anterior surface of femora shining, weakly microreticulate, punctate with punctures containing short seta; anteroventral furrow distinct, containing inconspicuous row of recumbent setae; anteroventral ridge simple, indistinct; without ventral teeth; posterior surface markedly microreticulate, dull; in profemur posterior surface with shallow punctures and sparse setae, without posteroventral ridge; in meso- and metafemur posterior surface impunctate, nude, with indistinct posteroventral ridge. Metafemur in repose not reaching elytral apex; subapically without stridulatory patch; dorsoposterior edge simple, without rows of denticles or scales; suture with trochanter oblique with ventral edge. Tibiae with fine longitudinal ridges bordered by sparse rows recumbent setae; dorsal edges of tibiae simple; apex with relatively large uncus, without premucro; uncus of metatibia bent ventrad at right angle. Anterior setose comb of metatibia oblique, from base of uncus to midline. Tarsi with tarsomere 3 subtrapezoid, anteriorly markedly widened, shape of apical lobes symmetrical; tarsomere 3 ca. 2 X as wide as tarsomere 2, ca. 1.6 X as long as tarsomere 2; claw-segment inserted in basal half of tarsomere 3; tarsomere 5 relatively long, 1.6 X as long as tarsomere 3; tarsal claws relatively large.

Abdomen. Ventrites markedly microreticulate, dull, with sparse suberect setae. Ventrite 1 behind metacoxa with dentiform swelling; center broadly impressed, concave; suture between ventrites 1-2 laterally distinct, medially effaced. Ventrite 2 along posterior margin raised, forming edge. Ventrites 3-4 narrow, of equal length, without punctures. Ventrite 5 relatively flat, subapically with shallow impression, weakly polished, apically sparsely setose. Terminalia. Sternite VIII ( Fig. 80 ) subtrapezoid, sides converging to subtruncate apex, at base ca. 3 X wider than long; medially weakly sclerotized, laterally more distinctly sclerotized; apex sublaterally densely setose. Sternite IX ( Fig. 80 ) straight; apical arms forming “V”, only apical 1/4 covered by sternite VIII. Tegmen ( Fig. 81 ) with complete, slender ring, broken in lectotype; parameroid lobes distinct, medially approximate, apically without microchaetae; apodeme relatively long. Aedeagus ( Figs. 78–79, 82–83 ) with sides of body subparallel, rounded towards apex when viewed vertically, medially apex extended into obliquely truncate tip; aedeagal body in lateral aspect highly convex and relatively thick at middle; dorsal surface subglabrous, apical orifice laterally with few inconspicuous setae; membrane of ostium transversely folded; with one pair of transverse, brace-like endophallic sclerites at middle of aedeagal body; apodemes ca. 1.9 X as long as aedeagal body; transfer apparatus compact, simple, symmetrical, cup-shaped, holding short spiniform anterior process; ductus ejaculatorius ca. 2 X as long as aedeagus, internally strongly sclerotized in basal portion, more apically less sclerotized, slightly thicker but without marked swelling.

Female paralectotype. Same as holotype except: Length. Pronotum + elytra 1.56 mm. Rostrum dorsally at extreme base punctate-rugose, apically becoming subglabrous, sparsely punctate with minute punctures; epistome indistinct, smooth. Thoracic venter. Disc of metaventrite flat except anteriorly sulcate. Legs. Uncus of metatibia gently curved, like in other tibiae. Abdomen. Disc of ventrite 1 flat. Terminalia ( Figs. 84–88 ). Tergite VIII ( Fig. 88 ) as long as wide, subtrapezoid, apical tip subtruncate, crenate. Sternite VIII ( Fig. 85 ) with apical plate subrotund, medially with small membranous area, apex rounded, sparsely setose. Coxite ( Fig. 86 ) without conspicuous setae, 2.5 X as long as stylus. Stylus ( Fig. 86 ) straight, parallel-sided, apically with sparse short setae. Bursa copulatrix ( Figs. 84 ) membranous, without sclerites; ductus spermathecae sclerotized throughout. Spermatheca ( Fig. 87 ) apically with relatively wide lumen; apical 1/5 solid chitinous.

Intraspecific variation. Length, pronotum + elytron: males 1.13–1.44 mm (n=4, x =1.33 ± 0.14); females 1.40–1.59 mm (n=7, x =1.52 ± 0.06). Color of body black, antenna and tarsi ferruginous; or, in teneral specimens entirely ferruginous. Pronotum 1.18–1.29 X wider than long in males (n=4, x =1.25 ± 0.05), 1.15–1.24 X wider than long in females (n=6, x =1.19 ± 0.03). Elytra 1.04–1.18 X longer than wide in males (n=4, x =1.12 ± 0.06), 1.04–1.12 X longer than wide in females (n=6, x =1.07 ± 0.03).

Material examined. Type specimens. Male, lectotype: PAPUA NEW GUINEA, Morobe Prov.. Labels ( Fig. 74 ): 1) [rectangular, white] “Sattelberg, Huon-Golf [printed]” 2) [rectangular, white] “N. Guinea, Biró 1899 [printed]” 3) [rectangular, white, with red asterisk] “ Microgymnapterus minutus n. sp. [Voss´handwriting] E.Voss det, 1959 [printed]” 4) [rectangular, white with red margin] “ Holotypus [printed] 1960, Microgymnapterus minutus Voss ” 5) [red, rectangular] “ LECTOTYPE, Microgymnapterus minutus Voss , det. A. Riedel 2010 [printed]” 6) [white, rectangular] “ Trigonopterus micros nom. n., det. A. Riedel 2010 [printed]” condition: specimen slightly teneral; ventrite 1 anteriorly pushed dorsad exposing posterior margin of metaventrite and metacoxae; pointmounted; genitalia in glycerol in microtube ( HNHM). Paralectotypes: 4 females, same data as lectotype ( HNHM); 2 males, same data as lectotype ( ZMH). Other specimens. PAPUA NEW GUINEA, Morobe Prov., Huon peninsula, Sattelberg: 1 male, ARC 1317, EMBL Accession# HE 565593 , 810m, S06° 29.225´E147° 46.272´, sifted, 18.X.2009, leg. A.Riedel ( SMNK); 1 male, ARC 1318, EMBL Accession# HE565594 , same collecting data ( SMNK); 1 female, ARC 1319, EMBL Accession# HE565595 , same collecting data ( SMNK); 1 female, ARC 1320, EMBL Accession# XXXX, same collecting data ( SMNK); 13 females [in ethanol], 2 males [CP-dried for µCT], same collecting data ( SMNK); 1 male, 15 females [in ethanol], 810m, S06° 29.317´E147° 46.163´, sifted, 19.X.2009 ( SMNK); 3 females [in ethanol], 750m, S06° 29.422´E147° 46.219´, sifted, 19.X.2009 ( SMNK); 2 females [in ethanol], 775m, S06° 29.376´E147° 46.224´, sifted, 20.X.2009 ( SMNK).

Distribution. PAPUA NEW GUINEA, Morobe Prov. (Sattelberg). Elevation: 775– 810 m.

Notes. VOSS (1960) did not designate a holotype in the original description. The labels stating “ Holotype ”, respectively “ Paratype ” have subsequently been added by Z.Kaszab, late curator at HNHM and they are not valid designations. Voss states “Sattelberg” as the type locality; however, two specimens labeled “ Paratypes ” are from “Astrolabe Bay, Mt. Hansemann”. It is likely that they are part of the type series and that Voss simply overlooked their different origin. However, no clear evidence exists and therefore, they are treated as not belonging to the type series. In fact, they represent a different species, described as T. oblitus sp.n. below. There remain 5 specimens from HNHM and two from ZMH; three additional syntypes may exist. To ensure stability of nomenclature a lectotype is designated herein. The only male from HNHM bearing both Kaszab´s holotype-label and Voss´s identification label is designated lectotype. Three females from HNHM and two males from ZMH are designated paralectotypes.

Figures

FIGURES 72 – 75. Trigonopterus micros, lectotype: (72) dorsal aspect; (73) frontal aspect; (74) labels; (75) lateral aspect. FIGURES 76 – 77. T. micros, male specimen (76) ventral aspect; (77) thanatosis position, lateral aspect.

FIGURES 78 – 83. Male terminalia of Trigonopterus micros, lectotype: (78, 82) aedeagus, lateral aspect; (79, 83) aedeagus, dorsal aspect; (80) sternite VIII – IX; (81) tegmen.

FIGURES 84 – 88. Female terminalia of Trigonopterus micros, paralectotype: (84) overview; (85) sternite VIII; (86) coxite; (87) spermatheca; (88) tergite VIII.