Trigonopterus scaphioides (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 : 38-43

Trigonopterus scaphioides (Pascoe)

Idotasia scaphioides Pascoe, 1871: 262 . Type locality: Salawati Island, Saylee. Idotasia egena Pascoe, 1876: 58 .

Trigonopterus egena (Pascoe) : Lyal (1993: 142) Trigonopterus egenus (Pascoe)

( Figs. 120–141 )

Diagnosis. Body ( Figs. 120–121 , 127–128 ) subrhomboid, black, polished, punctate. Elytral stria 9 basally near humerus with 7 punctures enlarged, foveate, laterally bordered by distinct costa. Intercoxal ridge of metaventrite posteriorly with deep notch. Femora 1/3 from apex with small tooth. Metafemur subapically with stridulatory patch; ventroanterior edge and ventroposterior edge with dense row of suberect setae. Metatibia apically with uncus and distinct premucro. Aedeagus ( Figs. 134–136, 140–141 ).

Description. Lectotype, male ( Figs. 120–126 , 134–135, 136–141 ). Length. Pronotum + elytra 3.3 mm. Color black, except antenna ferruginous, tarsi deep ferruginous. Integument of elytra and pronotum polished, punctate, nude; punctures of femora with sparse recumbent setae, without scales.

Habitus subrhomboid, with marked constriction between prothorax and elytra; torso in profile dorsally evenly convex. In thanatosis ( Fig. 123 ) legs forming compact unit, sticking out from horizontal body plane at ca. 80°; dorsal edge of metafemur distant from elytral edge; femora partly overlapping tibiae; pro- and mesofemur fully contiguous; gap between base of meso- and metafemur distinct.

Rostrum ( Figs. 122, 124 ) ca. 2.5 X as long as wide at base; in profile markedly curved ventrad, convex, apical half straight; dorsal surface in basal half punctate-rugose, median ridge and pair of submedian ridges low and very indistinct, with mesally directed inconspicuous scales; in anterior half sculpture flattened, with minute punctures, sparsely setose, cuticle shining; epistome indistinct, simple, without tooth.

Head. Eye subtriangular, largely concealed by pronotum when in thanatosis position; dorsal margin bordered by distinct furrow. Forehead between eyes slightly narrower than rostral base (0.8 X), deeply rugose-punctate, vertex behind eyes glabrous.

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

Pronotum 1.27 X wider than long, widest at base, sides weakly converging in straight line, subapically more distinctly converging to apex, without subapical constriction; anterior and posterior margins straight; disc smooth except densely punctate with moderately large punctures, interspaces subequal to puncture´s diameter; along submedian line with 19 punctures; narrow midline impunctate; laterally smoothly bent towards sides; laterally behind procoxa weakly cavernous; postocular lobe subangulate, evenly continuous with straight profile of marginal carina, antecoxal projection of marginal carina subacute, directed ventroposterad, inconspicuous; side above procoxa simple, without fovea.

Elytra subovate, basally truncate, 1.24 X longer than wide, 1.34 X wider than base of pronotum, widest in basal 0.29 of elytral length; in profile dorsally smoothly convex, 0.56 X as deep as long; striae marked by very thin hairline impressions and row of small punctures; flat intervals with row of similar punctures, resulting in confused punctation; interspaces glabrous, polished; punctures bordering basal margin similar to elytral punctures further behind; stria 9 basally near humerus with 7 punctures enlarged, foveate, laterally bordered by distinct costa; subapically some punctures of stria 9 enlarged and deeply impressed; elytral apex simple, jointly evenly rounded, not extended ventrad.

Thoracic venter. Fig. 126 . Procoxa anteriorly punctate, anteroapically with blunt punctate-setose tooth, mesal face subglabrous, without row of deep punctures. Ventral setose fringe of pronotal hypomeron forming distinct but relatively short receptacle brush; modified setae medially longer than lateral setae. Mesothoracic receptacle broadly H-shaped with short side-walls, posteriorly steeply declivous, hind wall with pair of deep foveae containing each 5-6 narrow scales; ventrally produced beyond level of mesocoxal apex; ventral rim partly polished, with sparse punctures containing each a scale. Mesocoxa mesally flattened, subglabrous, posteriorly with few punctures and setae. Metaventrite medially 1.4 X longer than exposed part of mesoventrite, disc broadly concave, medially subglabrous, sublaterally deeply punctate; lateral intercoxal ridge markedly protruding ventrad, in lateral aspect ventrally obliquely truncate, in ventral aspect intercoxal ridge posteriorly with deep notch splitting ridge into strongly oblique inner branch straight outer branch hanging somewhat over anterior margin of metacoxa; anterior rim of metacoxal cavity without secondary denticle. Sides of metaventrite glabrous, dorsally surface even with epipleuron, suture bordered by row of 5 punctures, ventrally bordered by costa; lateral surface of intercoxal ridge microreticulate, with few coarse punctures. Metacoxa mesally depressed, with few inconspicuous setae; without distinct teeth.

Legs. Femora markedly compressed laterally; with distinct anteroventral ridge abruptly terminating 1/3 from apex forming small tooth; posteroventral ridge less marked but still distinct; without ventral teeth; anteroventral furrow distinct, bordered by fringe of inconspicuous scales. Pro-, meso- and metafemur of similar size, sides subparallel; anteriorly weakly microreticulate, shining, densely punctate, punctures containing each one recumbent seta. Profemur posteriorly basally swollen and posteroventral ridge in this area markedly projecting, bordered by fringe of erect setae; at middle with elongate subglabrous pit. Mesofemur with posterior surface at middle and subapically punctate, remainder impunctate, microreticulate or striate, bordering posteroventral ridge with furrow containing row of setae. Metafemur in repose reaching elytral apex; posterior surface largely subglabrous, with one ventral and one dorsal row of setiferous punctures; subapical posterior surface with distinct stridulatory patch of transverse striation; basal limits of stridulatory patch ill-defined; ventroanterior edge and ventroposterior edge with dense row of suberect setae; dorsoposterior edge with 4 indistinct denticles, dorsal surface without distinct vestiture, only with sparse setae; suture with trochanter oblique with ventral edge. Tibiae with fine longitudinal ridges bordered by rows of dorsad pointing setae; dorsal edges tibiae simple; apex of metatibia with uncus and with smaller premucro, premucro of pro- and mesotibia indistinct. 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, their length subequal; claw-segment inserted in basal half of tarsomere 3; tarsomere 5 relatively long, 1.2 X as long as tarsomere 3; tarsal claws minute. Abdomen. Ventrite 1 behind metacoxa weakly swollen, without distinct protuberance. Ventrites 1 and 2 medially with common glabrous concavity, suture between ventrites 1 and 2 completely effaced; laterally ventrites 1 and 2 microreticulate, dull, punctate, suture distinct. Ventrites 3-4 narrow, of equal length, medially glabrous, laterally dull, with three setiferous punctures. Ventrite 5 at middle weakly swollen, flattened, polished, sparsely punctate; laterally coarsely punctate, dull, with suberect scales; apex simple, not crenulate.

Terminalia. Sternite VIII ( Figs. 138–139 ) subtruncate, apically weakly convex, sides markedly converging to apex, at base 2.5 X wider than long; laterally and along base well-sclerotized, medially membranous; apex laterally densely setose. Sternite IX ( Fig. 138 ) straight, apical arms U-shaped and half-covered by sternite VIII. Tegmen ( Fig. 137 ) with complete, slender ring, apodeme moderately long, parameroid lobes medially approximate. Aedeagus ( Figs. 134–135, 140–141 ); body with sides subparallel; apex asymmetrical, subtruncate, with lateral angles produced, mesally separated by oblique fold; right lateral angle projecting beyond weakly convex median tip, left lateral angle somewhat shorter; subglabrous, apex and dorsal surface laterally behind ostium sparsely setose; ostium with 3 asymmetrical sclerites; endophallus with several narrow sclerites of sinuate shape and asymmetrical position; apodemes broken in lectotype, ca. 1.9 X as long as aedeagal body; transfer apparatus complex, asymmetrical, with two contorted rods but without true flagellum; ductus ejaculatorius ca. 2 X as long as aedeagus, internally strongly sclerotized, basally near insertion with transfer apparatus relatively thin, more apically with marked swelling (“bulbus ejaculatorius”).

Material examined. Type specimens: Idotasia scaphioides Pascoe , lectotype by present designation, male: INDONESIA, West Papua: Salawatti Isl., Saylee; labels (fig.125): 1) [blue, ovate] “Saylee [hand-written]” 2) [rectangular, white] “ Idotasia scaphioides [hand-written]” 4) [rectangular, white] “Pascoe Coll. B.M.1893-60 [printed]” 5) [round, white with blue margin] “ SYNTYPE [printed]” 6) [rectangular, red] “ LECTOTYPE, Idotasia scaphioides Pascoe , det A.Riedel 2007 [printed]”; condition: specimen originally mounted on minuten pin, puncturing right elytron and breaking away a large portion of the right thoracic venter which is missing together with the right mid- and hind leg; remounted on point ( BMNH).

Idotasia egena Pascoe , lectotype by present designation, male ( Figs. 127–133 ): labels (fig. 132): 1) [yellowish, ovate] “N.Z, Waikato? [hand-written]” 2) [rectangular, white] “ Idotasia egena Typus, Pasc. [hand-written]” 4) [rectangular, white] “Pascoe Coll. B.M.1893-60 [printed]” 5) [rectangular, white] I. egena Pasc. [hand-written]” 6) [round, white with red margin] “ HOLOTYPE [printed]” 7) [rectangular, red] “ LECTOTYPE, Idotasia egena Pascoe , det A.Riedel 2010 [printed]”; condition: fair, point-mounted; genitalia in glycerol in microtube ( BMNH).

Distribution. INDONESIA, West Papua (Salawati Isl.: Saylee). This locality is on Salawati Island where Wallace´s assistant Mr. Allen had collected ( Wallace, 1869); it is presumably in the area of the Sele Strait on its southeast coast. As suspected by Lyal (1993) the type specimen of T. egenus was originally mislabeled and does not originate from New Zealand, but from Indonesia. It is clearly a junior synonym of T. scaphioides . The species group it belongs to occurs with a number of other undescribed species in the Maluku Islands. A species of highly endemic beetles, restricted to Maluku and to the Western tip of New Guinea is unlikely to form a local population in New Zealand.

Notes. Pascoe (1871) did not designate a holotype in the original description of I. scaphioides but quotes specimens from three localities (“Batchian, Saylee (Gilolo, var.?)”). Three syntypes stored at the BMNH could be examined. A male and a female syntype from Batchian belong to a species different from the male from Saylee.

Unfortunately, the endophallus of the Batchian male was lost during preparation, and its diagnosis among closely related species may no longer be possible. Therefore, the male syntype from Saylee is here designated lectotype to ensure stability of nomenclature.

Pascoe (1876) did not designate a holotype in the original description of I. egena 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. The species epithet of I. egena is based on the Latin adjective egenus , -a, -um (poor, needy, indigent) and is of female gender in combination with Idotasia . When it is combined with the genus Trigonopterus (male gender), the name must be “ T. egenus ”.

Figures

FIGURES 120 – 126. Trigonopterus scaphioides, lectotype: (120) as originally mounted, dorsal aspect; (121) dorsal aspect; (122) frontal aspect; (123) thanatosis position, lateral aspect; (124) lateral aspect; (125) labels; (126) ventral aspect.

FIGURES 127 – 133. Trigonopterus scaphioides. Lectotype of Idotasia egena: (127) as originally mounted, dorsal aspect; (128) dorsal aspect; (129) frontal aspect; (130) ventral aspect; (131) lateral aspect; (132) labels; (133) thanatosis position, lateral aspect.

FIGURES 134 – 141. Male terminalia of Trigonopterus scaphioides; lectotype, except fig. 136: (135, 140) aedeagus, lateral aspect; (134, 141) aedeagus, dorsal aspect; (136) aedeagus of Idotasia egena, lectotype, dorsal aspect; (137) tegmen; (138 – 139) sternite VIII – IX.