Metamasius pilirostris 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 : 598-600

Metamasius pilirostris Anderson , new species

Figs 6–8

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Diagnosis: This species (known only from a single female) is easily recognizable by the long, deep, pilose furrow running along the basal three-quarters of the length of the lateral faces of the rostrum ( Fig. 6 ) and the pronotal disc almost completely impunctate except for a concentration of punctures in the basal median longitudinal depression ( Fig. 7 ).

Description: Length, 12.5 mm in female; male not known. Rostrum ( Fig. 6 ) slightly shorter than length of pronotum, in profile of about same width as base of profemora and slightly narrowing towards apex, widest at base; impunctate or nearly so throughout almost all of length except for base where deeply, densely punctate; evenly arcuate from base to apex, cylindrical or nearly so; basal dilation very slight, very slightly wider (seen from above) than width of remainder of rostrum, subapically slightly pinched in dorsal view (teratological?); lower portion of lateral face with long, deep, pilose furrow running along the basal three-quarters of length; ventrally not sulcate or toothed; scrobe with posterior edge about width of apex of scape from front margin of eye. Antennal club with apical pilose portion shorter than sclerotized base, about one-third of total length of club. Pronotum ( Figs. 7–8 ) flat, slightly broadly longitudinally impressed in basal one-half, lateral margins subparallel to slightly beyond midlength then convergent to subapical constriction, tubulate to apex; disc largely impunctate except for large, widely spaced punctures in basal impression, tubulate apical area finely shallowly punctate, lateral margins with slightly larger, uniformly spaced punctures also extended down flanks; posterior margin extended posteriorly at middle. Elytra ( Figs. 7–8 ) with base sinuate, with slightly raised margin; lateral margins tapering from just behind humeri to near apex; striae well defined but individual punctures distinct; intervals impunctate. Pygidium ( Fig. 7 ) rounded-truncate, with a few large, deep punctures, not ridged medially. Thoracic sterna ( Fig. 8 ) with prosternum finely, densely punctate, similar punctures laterally on mesosternum and metasternum, but the latter medially impunctate, glossy; prosternum flat in front of procoxae, not tumid; distance between procoxae about width of antennal club; distance between mesocoxae about diameter of a mesocoxa. Abdominal ventrites ( Fig. 8 ) 1–4 similarly medially completely impunctate, glossy, laterally regularly densely punctate, punctures moderately large, deep; ventrite 1 slightly convex; ventrite 5 in both sexes regularly densely punctate, lacking any swellings or setae. Legs ( Fig. 8 ) with femora very finely punctate, with inner margin of protibia with short setae; all femora linear, slightly clavate apically, mesofemur not reaching apex of metasternum; metatibia with inner margin slightly sinuate, with fringe of dense, short setae throughout almost all of length; all tarsi with tarsomere 3 slightly more than twice as wide as tarsomere 2, finely pilose ventrally except in broad, triangular patch at base, slightly asymmetrical on mesothoracic and metathoracic legs; tarsomere 5 inserted just before middle of tarsomere 3.

Specimens examined: Holotype female (not dissected), labeled “ Colombie / Cordillere vers occid. / Rio Yurumangui ”, “Museum Paris / 1933 / E. Aubert de la Rue ” ( MNHN).

This locality would appear to be in Parque Nacional Natural Farallones, Buenaventura Municipality, Valle del Cauca Department (approximate coordinates 3.3, -77.1). The river flows on the western side of the western branch (occidental) of the Andes consistent with the information on the label.

Etymology: This species is named after the narrow line of setae running along each lateral face of the rostrum.

Notes: This species is similar in general body form and in the largely impunctate pronotum with punctate basal depression, to M. nudiventris and M. sellatus . In Vaurie (1966), the species will key to M. peruanus in couplet 15 due to the rostrum with a lateral pilose sulcus, but females of that species have a strong ventrally directed tooth (peduncle of Vaurie 1966; fig. 100) at the apex of the rostrum whereas such a tooth is not present in the female of M. pilirostris . The male of M. pilirostris is not known but it is likely to have the same lateral pilose sulcus on the rostrum as in the female (as is the situation with M. peruanus , the only other species known with a pilose lateral rostral sulcus).

More than half of the species of Metamasius show secondary sexual differences, usually most pronounced in the males. Males of at least 30 species have long fringes or conspicuous tufts of hairs on the inner side of the pro- or metatibiae ( Vaurie 1966). Vaurie (1966: 221) mentions four species known only from males at that time, none of which are likely candidates as potentially conspecific with M. pilirostris .

The only known specimen bears a large handwritten label “rostre hairs no / basal dilation, / constricted dor- / sally near apex / near sellatus Champ ”. This same label has “n. sp. A. Metamasius ” handwritten perpendicular to the other writing. I do not recognize the handwriting although it is not that of Patricia Vaurie.

Figures

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

FIGURES 7–8. Metamasius pilirostris. 7, Dorsal habitus, female. 8, Lateral habitus, female.