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

description: Metamasius atwoodi Anderson, new species
(Figs. 51­52, 57­62)
Identification.— Metamasius atwoodi is endemic to Cocos Island off the southwestern coast of Costa Rica. This distinctive species is easily distinguished by its strongly dorsoventrally compressed form and almost planar dorsal and ventral surfaces (Fig. 52); pronotum with punctures uniformly dense and small, extended from disc onto flanks and prosternum; rostrum very narrow, subcylindrical, evenly curved (Figs. 51, 57­58); pygidium with a distinct tuft of elongate golden setae arising from the apical one­half of the midline (Figs. 61­62); legs short, the hind femora only reaching the apex of ventrite 3; and femora with outer faces uniformly densely punctate. The only other species of Metamasius recorded from Cocos Island is M. hebetatus.
Description.— Male, length, 9.5 mm; width, 3.4 mm. Female, length, 9.0­ 11.4 mm; width, 3.3­4.3 mm. Color red with black; head black, rostrum red to slightly infuscate; pronotal disc red, with infuscate anterior margin and variously developed narrow median line; elytra red with black laterally, in variously black to infuscate anteromedian band or spot, subapically at more or less posterior one­quarter in some specimens, and in a variously infuscate sutural margin; legs red, apices of femora infuscate. Venter red, sutures variously infuscate.
Rostrum subequal to length pronotum; elongate, subcylindrical, very narrow, evenly curved, very finely shallowly punctate only at extreme base; base of rostrum abruptly expanded in dorsal view; in lateral view slightly wider at base, expansion gradual, basal expanded area short, about one­sixth total rostral length. Rostrum glabrous ventrally; peduncle flat. Scrobe with posterior margin about width of base of scape from anterior margin of eyes. Antenna with scape more or less one­half length rostrum; club slightly laterally compressed, oval; apical pilose part subequal to length basal glabrous part. Pronotum with lateral margins subparallel in basal one­half, convergent subapically, tubulate to apex; disc and flanks uniformly moderately deeply punctate throughout; uniformly flat, with imperceptible subbasal impression. Pronotum with length slightly greater than width. Elytra with length one and two­thirds times length pronotum; intervals finely punctate in two or three irregular rows, flat; striae with distinct, moderately deep, small punctures, punctures of striae 7­9 larger and merged with punctures of adjacent striae. Scutellum elongate, “U” shaped, length about twice width at base, flat. Pygidium flat to slightly convex, not tumescent; coarsely deeply irregularly punctate throughout; apex subtruncate; apical one­half of midline with dense elongate golden setae forming prominent tuft. Ventrally with front coxae separated by from one­fourth to one­third width of coxa; prosternum densely, regularly punctate, flat between and anterior to front coxae. Lateral portions of meso­, metasternum and ventrites 3 to 5 moderately deeply, densely punctate; punctures larger, deeper laterally on ventrites 1 and 2; last ventrite flat. Legs short, densely regularly punctate, especially on outer face of femora; femora slightly clavate, short, hind femur only reaching apex of ventrite 3; inner margins of middle and hind tibiae of male very slightly inwardly expanded subbasally, straight in female; with setae in apical three­quarters, setae of more or less uniform length, short, stout. Tarsi each with third article very widely dilated, completely pilose ventrally; front tarsus with third article symmetrical, third article of middle and hind tarsi asymmetrical, outer lobe noticeably wider than inner lobe, especially on hind tarsus; apical margin of third articles very slightly emarginate.
Variation.—There is very slight variation in the color pattern of this species, mainly in the extent of black on the elytra.
Sexual dimorphism.—The single male specimen examined has less dense and shorter setae on the pygidium and has the scape proportionally longer than in the female. Also, in males, the hind tibiae have the inner margins very slightly inwardly expanded near the base.
Material examined.—Male HOLOTYPE labelled “ Costa Rica. Prov. Puntarenas. / P.N. Isla del Coco. Bahia Wafer. / 1 m. Oct 1994. J.F. Quesada / Long:­ 87:03:30_Lat:5:32:45 #3314”, INBio barcode 2544733 (INBC). Female ALLOTYPE labelled as holotype, INBio barcode 2544728 (INBC). PARATYPES (9). Labelled as holotype (7; 2544723, 2544726, 2544727, 2544731, 2544732, 2544734, 2544735). COSTA RICA. PUNTARENAS PROVINCE. Isla del Coco, Bahia Chatan, 5­9 Fev 1993. (1; 1851696). Mirador, 11.II.1984, 1530', T.W. Sherry, T.K. Warner, Rooseveltia palm tree fall (1). Paratypes in CMNC, CWOB, INBC.
Distribution.— Costa Rica (Puntarenas [Isla del Coco]).
Natural history.—Adults were collected near sea level, likely on or near the coast. A single specimen has a fibrous pupal cell mounted along with the adult. This suggests this specimen was collected in the pupal cell or had recently emerged from it. The source plant of this fibrous material is unknown to me but one additional specimen was collected from a Rooseveltia (= Euterpe Mart.) palm tree fall and this might be the plant in question. No other information is available on natural history.
Derivation of specific name. In recognition of the support of noted Canadian author Margaret Atwood for systematics research, at her request, this species is named after her late father, Dr. Carl Atwood (1906-1993), a forest entomologist, most recently at the University of Toronto, where he was a professor from 1946-1972. Dr. Atwood was an active conservationist and one of the first to caution about the widespread use of insecticides to combat forestry pests because of detrimental effects, not only on the target pest, but on populations of the pest insects natural predators. Ms. Atwood was invited as the honourary recipient of the first name to be offered in support of the Nature Discovery Program and Fund, coordinated by the Canadian Museum of Nature in Ottawa.
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 50-52, DOI: 10.5281/zenodo.156033