Metamasius shchepaneki Anderson, new species
Creators: name: Anderson, Robert S.
Publisher: name: Zenodo
Year: 2002
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dryophthoridae
Metamasius
Metamasius shchepaneki

description: Metamasius shchepaneki Anderson, new species
(Figs. 103­104, 115­118)
Identification.—This species is easily confused with Cactophagus circumdatus, with which it shares an almost identical pattern of pronotal and elytral coloration. In both species the pronotum has a pair of broad orange stripes which follow the lateral margins and which are continued onto the elytra again following the lateral margins until about the midlength whereupon they each arc medially, and almost meet at the elytral suture at about the posterior one­third of the elytral length (Figs. 103­104). Metamasius shchepaneki, is however, separable from C. circumdatus by the much finer and denser punctation of the rostrum (especially laterally around the point of antennal insertion) in the former, and by the form of the subbasal area of the pronotal disc which in M. shchepaneki is flat and not transversely impressed as it is in C. circumdatus. Despite the similarities in color pattern and general appearance, M. shchepaneki males also possess a lateral unsclerotized line on the aedeagus and is thus not closely related to C. circumdatus, the males of which lack this lateral line.
Description.— Male, length, 9.8­11.5 mm; width 3.9­5.0 mm. Female, length, 13.8 mm; width 5.4 mm. Color black except for pair of broad lateral continuous orange stripes on pronotum continued onto the elytra at humerus, following lateral margins of elytra until more or less midlength whereupon each arcs medially towards elytral suture, stripes almost meeting at the elytral suture at about posterior one­third of elytral length.
Rostrum about two­thirds length pronotum; elongate, subcylindrical and shining, evenly slightly curved; finely, densely punctate throughout except impunctate at extreme apex; base of rostrum slightly expanded only at point of antennal insertion, basal area about one­fourth total rostral length; ventrally, just anterior to point of antennal insertion, with pair of small rounded prominences in male, lacking in female. Rostrum in lateral view subequal in width throughout length, not noticeably tapered towards apex; rostrum glabrous ventrally; peduncle flat, bilamellate anteriorly. Scrobe with posterior margin separated from anterior margin of eyes by about width of base of scape. Antennal scape long, about two­thirds length rostrum; club slightly laterally compressed, oval; apical pilose part subequal in length to, or very slightly shorter than, basal glabrous part. Pronotum slightly longer than wide; lateral margins slightly convergent in basal one­half, moderately convergent from midlength to apex; very sparsely, finely punctate except deeper, larger on flanks and irregularly on basal region of disc at middle; disc flat postmedially to at most very slightly concave, not transversely impressed. Elytra one and one­third times length pronotum; with striae vaguely punctate basally, intervals impunctate, flat. Scutellum elongate, broad; length very slightly greater than width at base, flat. Pygidium uniformly slightly convex, not tumescent; sparsely setose and punctate throughout; apex subtruncate with pair of small apical tufts of short setae. Ventrally with front coxae separated by about onehalf width of coxa; prosternum flat, with very slight rounded swelling anterior to each coxa. Mesosternum and lateral portions of metasternum and ventrites shallowly punctate; middle of metasternum and ventrites 1 and 2 finely punctate, shining. Last ventrite of male flat at middle, with large densely setose patch; of female, glabrous, punctate, extreme apex slightly deflexed ventrally. Legs short, shallowly punctate and very finely setose throughout; femora slightly clavate, short, hind femur almost reaching apex ventrite 4; inner margins of all tibiae with sparse short setae arranged in pectinate manner; all tibiae straight. Tarsi each with third article widely dilated, pilose ventrally except glabrous in broad basal fusiform area; front and hind tarsal third articles symmetrical, middle tarsal third articles slightly asymetrical and with apical margins very slightly emarginate.
Variation.—There is slight variation in the pattern of elytral coloration with the black markings extended further posteriorly and broader in some specimens.
Sexual dimorphism.—In males, the apex of ventrite 5 has a large densely setose patch, whereas in the female this area lacks any distinct hairs, although the extreme apex is deflexed ventrally. Also, the rostrum of males has a slight ventral swelling immediately anterior to the point of antennal insertion; such a swelling is lacking in females.
Material Examined.— Male HOLOTYPE labelled “ PANAMA. Panama Pr. / Cerro Campana, 850m / 8°40’N, 79°56’W. / 8 Apr. 72, Stockwell (CMNC). Female ALLO­ TYPE labelled as holotype except “ 820m, 12 May 74 ” and “on vine / Carludovica sp.” (CMNC). PARATYPES (3, 1). COSTA RICA. CARTAGO PROVINCE. Turrialba, Parque Nacional Barbilla, Senero a Rio Danta, 800m, 24 April 2001, W. Arana, LN596387, 218279 (1; 3173305). Guanacaste PROVINCE. Faldas, S.W. Volcan Cacao, 1150­1250m, Jun 1996, C. Moraga, I. Villegas, L_N_322300_376000 #7646 (1; 2422728). PANAMA. PANAMA PROVINCE. Cerro Campana, 900­950m, 5 Jun 1995 ­ 0 4, R.S. Anderson (1). 850 m, 29.v.1970 (1). Paratypes in CMNC, INBC.
Distribution.— Costa Rica (Cartago, Guanacaste), Panama (Panama).
Natural history.— All specimens have been collected in montane evergreen forest or cloud forest at elevations from 820­1250m. The allotype is labelled as collected on a vine, Carludovica sp., but this most likely refers to a species of Asplundia (both genera Cyclanthaceae) as no species of the former climb. Interestingly, M. sierrakowskyi has also been collected on flowers of Cyclanthaceae.
Derivation of specific name.—This species is named after Mike Shchepanek of Ottawa, Ontario, Canada, and Collection Manager for Botany at the Canadian Museum of Nature.
Comments.—In 1980 Patricia Vaurie labelled what is here designated as the holotype of this species as Metamasius sp.? and added a second label noting that it was “not amoenus, not circumdatus, and not circumjectus ”.
description: Published as part of Anderson, Robert S., 2002, The Dryophthoridae of Costa Rica and Panama: Checklist with keys, new synonymy and descriptions of new species of Cactophagus, Mesocordylus, Metamasius and Rhodobaenus (Coleoptera; Curculionoidea), pp. 1-94 in Zootaxa 80 on pages 70-73, DOI: 10.5281/zenodo.156033