Thyestetha oblita Eberle & Riedel

Eberle, Jonas, Tänzler, Rene & Riedel, Alexander, 2012, Revision and phylogenetic analysis of the Papuan weevil genus Thyestetha Pascoe (Coleoptera, Curculionidae, Cryptorhynchinae), Zootaxa 3355 (1), pp. 1-28 : 21-22

Thyestetha oblita Eberle & Riedel sp. n.

( Figs. 7 , 16 , 44, 49–50 , 71 )

Diagnosis. Pronotum densely punctate with small punctures, punctures finer near base, black. Elytra black, striae distinct from base to apex ( Figs. 7 , 16 ). Rostral canal between procoxae with scales. Dorsal squamose line of metafemur moderately dense, scales slender; male metafemur in apical third with posteroventral ridge abruptly ending and markedly protruding proximally (as in Fig. 26). Aedeagus ( Figs. 49–50 ) with apex weakly curved ventrad; apical margin rounded ( Fig. 44 ).

Description. Holotype, male. Length. Pronotum + elytra: 4.2 mm. Color. Antenna and tarsi ferruginous; rostrum and legs dark ferruginous to black; remainder black. Habitus subovate, in dorsal view almost without constriction between pronotum and elytra ( Fig. 7 ); profile dorsally with shallow constriction between pronotum and elytron ( Fig. 16 ).

Rostrum 5.5 X as long as wide at base. Head. Vertex coarsely punctate, with few white scales near eye.

Prothorax 1.2 X wider than long; anterior 1/4 of disc punctate with small punctures, remainder subglabrous and with minute punctures (except for row of coarse punctures along base), interstices smooth, polished; sides punctate with small punctures, basal margin smooth; postocular lobe coarsely punctate with larger punctures; marginal carina externally along edge with few whitish scales; rostral canal with scattered long setae, between procoxae with sparse whitish scales.

Elytra 1.1 X longer than wide; sides rounded; apex slightly extended, jointly rounded; punctures of striae 1–9 moderately impressed from base to apex; interstices between punctures of stria 1–5 2– 4 X wider than diameter of punctures, interstices between punctures of stria 6–8 larger, interstices of stria 9 subequal to diameter of punctures. Metanepisternum 2.9 X wider than high.

Thoracic venter. Meso- and metaventrite with sparse whitish scales; metaventrite submedially behind mesocoxa with pair of moderate protrusions. Pro- and mesocoxa densely punctate, sparsely squamose; metacoxa glabrous; trochanters with sparse, coarse punctures containing small scales. Distance between mesocoxae subequal to width of mesocoxae.

Legs. Femora sparsely punctate, apically punctures denser, scales slender; dorsal squamose line of metafemur moderately dense, scales slender; anteroventral ridges relatively weak. Metafemur with posteroventral ridge in apical third abruptly ending and markedly protruding proximally (as in Fig. 26).

Abdomen. Ventrite 1 sparsely punctate, with few small whitish scales arising from punctures; ventrite 2 basally with few whitish scales; remaining ventrites subglabrous except apical margin of ventrite 5 sparsely squamose.

Terminalia. Aedeagus ( Figs. 44, 49–50 ). At middle slightly extended; apex rounded, weakly curved ventrad; lateral orificial sclerites medium-sized, inner portion 2 X longer than outer portion; anterior median orificial sclerite simple between 2nd and 3rd fold (as in Fig. 36 ). Dorsal contour of transfer apparatus sharply incised at middle, ventral contour angularly projecting; sclerites in basal half, dorsoventrally flattened, moderately distant, in apical half contiguous. Apodemes and base of aedeagus broken and missing.

Intraspecific variation. Size: Length 4.2–4.7 mm (n=2, x = 4.5 mm) in males. Head. Vertex of paratype slightly less densely punctate. Prothorax. Sides slightly more densely punctate.

Etymology. The epithet is based on the Latin oblitus (forgotten) and refers to the fact that it was part of the type series of T. carbonaria .

Material examined (2 males). Holotype: PAPUA NEW GUINEA, Milne Bay Prov., Milne Bay ; labels: 1) [golden rectangle] 2) [rectangular, white] 3 Milne B. Staudgr. [hand-written] 3) [rectangular, white] carbonaria Faust [hand-written] 4) [rectangular, blue] Coll. J. Faust, Ankauf 1900 [printed] 5) [rectangular, red] Type [printed] 6) [rectangular, white] Staatliches Museum für Tierkunde Dresden [printed] 7) [red, rectangular] PARALECTOTYPE, Thyestetha carbonaria Faust , det. Eberle & Riedel 2011 [printed] 8) [red, rectangular] HOLOTYPE, Thyestetha oblita sp.n., det. Eberle & Riedel 2011 [printed] condition: left metatibia and tarsus missing; base of aedeagus broken; apodemes missing; specimen originally point-mounted, remounted on card; genitalia in glycerol in microtube ( SMTD) . Paratype: NEW GUINEA; labels: 1) [rectangular, white] N. Guinea, Staudinger [hand-written] 2) [rectangular, white] Thyestetha nitida Pasc. [hand-written] 3) [rectangular, hand-written] Staatliches Museum für Tierkunde Dresden [printed] 4) [rectangular, blue] Sammlung K.F.Hartmann, Ankauf 1941.1 [printed] 7) [rectangular, red] PARATYPE, Thyestetha oblita sp. n., det. Eberle & Riedel 2011 [printed]. Condition: right protarsus broken and missing; base of aedeagus broken; left apodeme missing; specimen originally point-mounted, remounted on point; genitalia card-mounted ( SMTD) .

Distribution ( Fig. 71 ). Milne Bay.

Figures

FIGURE 71. Distribution of Thyestetha carbonaria, T. discolor sp. n., T. emarginata sp. n., T. nitida, and T. oblita sp. n..

FIGURES 1 – 9. Habitus of Thyestetha spp., dorsal aspect: (1) T. carbonaria, lectotype; (2) T. discolor sp. n., holotype; (3) T. emarginata sp. n., holotype; (4) T. glabra sp. n., holotype; (5) T. lubrica sp. n., holotype; (6) T. nitida; (7) T. oblita sp. n., holotype; (8) T. puncticollis sp. n., holotype; (9) T. splendens sp. n., holotype.

FIGURES 10 – 18. Habitus of Thyestetha spp., lateral aspect: (10) T. carbonaria, lectotype; (11) T. discolor sp. n., holotype; (12) T. emarginata sp. n., holotype; (13) T. glabra sp. n., holotype; (14) T. lubrica sp. n., holotype; (15) T. nitida, lectotype; (16) T. oblita sp. n., holotype; (17) T. puncticollis sp. n., holotype; (18) T. splendens sp. n., holotype.

FIGURES 37 – 54. Aedeagus of Thyestetha spp. in dorsal and lateral aspect: (37, 38) T. carbonaria, lectotype; (39, 40) T. discolor sp. n., holotype; (41, 42) T. glabra sp. n., holotype; (43) T. carbonaria, apex of aedeagus, ventral aspect; (44) T. oblita sp. n., holotype, apex of aedeagus, ventral aspect; (45, 46) T. lubrica sp. n., holotype; (47, 48) T. nitida, lectotype; (49, 50) T. oblita sp. n., holotype; (51, 52) T. puncticollis sp. n., holotype and (53, 54) T. splendens sp. n., holotype.

FIGURES 29 – 36. Male terminalia of Thyestetha spp.: (29 – 31) T. glabra sp. n., holotype: (29) tegmen, (30) tergite VII and (31) segments VIII – IX. (32 – 34) T. nitida: (32) tegmen, (33) tergite VII and (34) tergite VIII with sternite VIII and spiculum gastrale. Ostium, lateral aspect: (35) T. discolor sp. n., arrow and dashed line marking bulge between 2 nd and 3 rd fold (36) T. splendens sp. n..