Metamasius onorei Anderson, 2021

Anderson, Robert S., 2021, Two new species of Metamasius Horn, 1873 (Coleoptera: Curculionidae: Dryophthorinae) from Ecuador and Colombia, Zootaxa 4966 (5), pp. 596-600 : 596-598

Metamasius onorei Anderson , new species

Figs. 1–5

urn:lsid:zoobank.org:act:E3E5A577-28E8-41A5-88C7-FC3677834BFC

Diagnosis: This species is easily distinguished from all other Metamasius by the combination of being completely black; pronotum wide, flat to shallowly broadly concave ( Figs. 1–4 ); tarsomere 3 extremely wide on all legs (at least twice as wide as width of tarsomere 2) ( Fig. 5 ); mesoscutellum emarginate; venter impunctate; rostrum long, narrow, curved (noncrenulate ventrally in male) ( Figs. 1–4 ); metatibia in males and females with inner margin with fringe of dense, short, stout setae; protibia in males with apical one-half of inner margin with short setae (length about one-half width tibia).

Description: Length, 13.0– 14.8 mm in males, 11.5–12.5 mm in females. Rostrum ( Figs. 1–4 ) longer than pronotum in male, as long as or slightly longer than pronotum in female, in profile of about same width as protibia and of same width throughout except for slightly widened base; entirely impunctate, rather strongly, evenly arcuate from base to apex, very slightly laterally compressed; basal dilation abrupt, dilated in front, constricted behind, about twice as wide (seen from above) as width of remainder of rostrum; ventrally not sulcate or toothed; scrobe with posterior edge encroaching on front margin of eye. Antennal club with apical pilose portion subequal in length to sclerotized base. Pronotum ( Figs. 1–4 ) very flat, slightly broadly concave in some specimens, lateral margins subparallel in basal half then convergent to subapical constriction, tubulate to apex in female, margins more evenly rounded from base to subapical constriction; disc, including tubulate apex, entirely impunctate; basal depression lacking; posterior margin lobed at middle. Mesoscutellum emarginate anteriorly at middle. Elytra ( Figs. 1–4 ) with base straight, with slightly raised margin; lateral margins tapering from just behind humeri to near apex; striae well defined but individual punctures indistinct, less so laterally where small fine linearly arranged punctures are visible; intervals impunctate. Pygidium ( Figs. 1–2 ) rounded-truncate, regularly shallowly punctate except for impunctate median line, not ridged medially. Thoracic sterna ( Figs. 3–4 ) completely impunctate, glossy, except lateral extensions of mesosternum, which are densely punctate; prosternum convex at middle, not tumid; distance between procoxae about one-half width of a procoxa in male, slightly greater in female; distance between mesocoxae about twice diameter of a mesocoxa. Abdominal ventrites ( Figs. 3–4 ) similarly completely impunctate, glossy; male with ventrite 1 slightly concave at middle, female convex; ventrite 5 in both sexes lacking any swellings or setae. Legs ( Figs. 3–4 ) glossy, imperceptibly punctate, with inner margin of protibia of male with short setae about one-half the width of tibia in length; all femora linear, not distinctly swollen or clavate, mesofemur reaching beyond apex of metasternum; metatibia in males and females with inner margin very slightly sinuate, with fringe of dense, short, stout setae throughout at least apical three-quarters of length; all tarsi with third tarsomere about twice as wide as second, completely finely pilose ventrally in large pad, slightly asymmetrical; tarsomere 5 inserted near base of 3. Aedeagus with apex truncate; apodemes attached directly to sides; eighth tergum of male fringed with very long, golden setae.

Specimens examined: Holotype male, labeled “ Ecuador / Las Palmas / viii.1981 ”, “ G. Onore / Brit Mus / 1985-254” ( BMNH) . Paratypes, same data as holotype (1 male, 3 females, BMNH; 1 male 2 females, CMNC). One of the paratypes is labeled as “Las Pahpas” .

Correspondence with Giovanni Onore of Quito, Ecuador in April 2020 indicates that these labels were likely improperly transcribed when the specimens were mounted and the locality should read Las Pampas, in reference to San Francisco de Las Pampas, 1500 m (approximate coordinates 0.4, -78.9), one of the reserves of the Fundación Otonga, managed by Onore, and a place where he frequently collected.

Etymology: This species is named after Dr. Giovanni Onore, of Quito Ecuador and formerly of the Zoology Museum at the Pontifical Catholic University of Ecuador. For many years, he has been instrumental in facilitating and hosting entomologists in Ecuador and provided guidance to interesting places to study and collect.

Notes: The species bears some similarities to M. applicatus Hustache but the latter has at least some red in the dorsal color pattern, the protibia in males has the apical one-half of inner margin with long setae (length about as long or longer than the width tibia), the ventral surface is feebly punctate, more deeply and strongly on the prosternum and femora, and the pygidium is entirely ringed with setae and has a setose, median ridge.

In Vaurie (1966), the species may key to couplet 14 due to the emarginate mesoscutellum but in Metamasius anceps (Gyllenhal) (a different species and member of the Metamasius hemipterus subgroup of Vaurie 1966) the mesoscutellum is more bilobed than simply emarginate. If one passes couplet 14, one will proceed to couplet 42 along with M. vicarius Vaurie , M. applicatus , and M. tuberculipectus Hustache. The mesofemur in M. onorei is long, directing one to couplet 43 but the prosternum is at most slightly swollen in front of the procoxae, not tumid or protruding. If one proceeds to couplet 43, M. onorei can be recognized by the prosternum only slightly swollen in front of the procoxae, the entire ventral surface (except lateral projections of mesosternum) glossy and impunctate, and the male (and female) with the inner margin of the metatibia with a fringe of dense, short, stout setae.

Figures

FIGURES 1–4. Metamasius onorei. 1, Dorsal habitus, male. 2, Dorsal habitus, female. 3, Lateral habitus, male. 4, Lateral habitus, female.

FIGURES 5–6. 5, Metamasius onorei, metatarsus. 6, Metamasius pilirostris, lateral view of rostrum.