Megacerus (Megacerus) westcotti Romero, 2018

Nápoles, Jesús Romero, 2018, A New Species of the Seed Beetle Genus Megacerus Fåhraeus, 1839 (Coleoptera: Bruchidae) and Redescription of Megacerus centralis (Pic), with a Key to the Mexican Species and New Host and Distribution Records, The Coleopterists Bulletin 72 (3), pp. 531-540 : 534-536

Megacerus (Megacerus) westcotti Romero , new species

( Fig. 1a–d ) zoobank.org/ urn:lsid:zoobank.org:act:AFF721B2-4D60-4877-872C-2EAB1A9E6621

Type Series. Holotype and two paratypes: Sierra de Alamos , Sonora, MEXICO; XII/1987, collector unknown, reared from seed of Erythroxylum mexicanum Kunth (holotype and one paratype at CEAM, one paratype at USNM).

Description. Male ( Fig. 1a–d ). Length (pronotumelytra) 2.75–3.05 mm; width 1.55–1.67 mm; maximum thoracic depth 1.50–1.75 mm. Integument color: Body reddish brown, except head, antenna, a transverse mesal spot on pronotum, 3 spots on external margin on elytra and 2 indistinct areas on internal margin, metacoxa, ventral portion of metafemur, and 2 pygidial anteapical lateral spots black. Vestiture: Body with white pubescence, with scattered spots of yellowish setae; pygidium with white setae forming a dense, triangular, median, basal spot; spiracular areas not glabrous, clothed with whitish setae. Head: Short, constricted behind eyes; densely micropunctulate; frons very narrow with a strong median carina; ocular sinus 0.35–0.48X width of eye, posterior margin of eye protruding from adjacent surfaces; antennae pectinate from 4 th antennomere. Prothorax: Pronotum subconical, without lateral carina; disc convex, densely foveolate; prosternal process narrow, triangular, acute. Meso- and metathoraces: Scutellum square, bidentate apically; elytral striae with large punctures slightly wider than striae; striae 1–6 reaching elytral base, 7 reaching middle of humerus, 8–10 reaching humeral base; mesepimeron foveolate; metepisternum punctate with scattered foveolae and a dorsal curved carina; elytra with salient humeri. Legs: Metacoxa densely foveolate; metafemur moderately swollen, ventral carinae obsolete; internal ventral margin with very small subapical spine; metatibia straight, enlarged, with dorsomesal and ventral carinae, lateral and ventrolateral carinae obsolete; mucro longer than lateral coronal denticle. Abdomen: More or less telescoped, 5 th sternite deeply emarginate; pygidium vertical with scattered foveolae. Genitalia: Median lobe moderately long, wider at base; ventral valve triangular and deeply arcuate in lateral view; basal internal sac spinulate, with median group of about 25 spines followed by a double line of 6 spines and a basal group formed by 3 spines on each side ( Fig.1d ); lateral lobes fused, wider than apex of median lobe, with apical setae, without median flap in ventral view.

Female. Unknown.

Host Plant. Erythroxylum mexicanum Kunth. (Erythroxylaceae) .

Distribution. Mexico (Sonora).

Etymology. This species is dedicated to Richard L. Westcott, a friend of the author and a great collector. We shared field trips full of exciting experiences many times.

Diagnosis. This species is near M. cubiculus within the subgenus Megacerus , which is characterized by having 22–27 spines in the internal sac of the male genitalia and only one pair of spines posteriorly. In contrast, M. westcotti has more spines, about 43, and the posterior spines are grouped into two groups of three. Erythroxylaceae represents a new host family for both the genus and the subfamily.

Figures

Fig. 1. Male Megacerus westcotti. a) Dorsal habitus, b) Lateral habitus, c) Pygidium, d) Genitalia.