Corthylus granulocristatus Atkinson, 2020

Atkinson, Thomas H., 2020, New species, new records and synonymy of Mexican Corthylus Erichson, 1834 (Coleoptera: Curculionidae: Scolytinae), Insecta Mundi 2020 (792), pp. 1-25 : 10-12

Corthylus granulocristatus Atkinson , new species

Fig. 4 E, F ; Fig. 7 A–D

Diagnosis. This species is similar to C. cristatus and C. cristatulus with respect to the elevated serrate crest on interstriae 3 and the dense punctures of the elytra. It is distinguished from these by the presence of pointed granules at the base of all declivital interstriae.

Female. Length: 1.87 mm, maximum width: 0.77 mm; length of elytra: 1.07 mm; length to width: 2.4; elytral length/total length: 0.57; elytral length/width: 1.39. (n = 1).

Frons evenly concave from epistoma to vertex. Lower surface reticulate, without vestiture. Sparse setae more abundant on sides and upper portion of frons, marginal setae longer than those nearer the center, slightly incurved margins. Antenna slightly asymmetrical, 1 st and 2 nd sutures indicated by external grooves, 1 st partly septate. Cirrus short, longest setae less than length of 3 rd segment of antennal club.

Anterior margin of pronotum broadly rounded, unarmed. First row of asperities posterior to margin erect. Remaining asperities on anterior slope not elevated, weakly developed, obsolete at summit. Pronotal disc shining, with dense, deep punctures, separated by about 2× their diameters, each associated with a short recumbent seta, about length of spacing between punctures.

Striae and interstriae indistinct on elytral disc, all punctures similar in size and completely confused, those at base of elytral about the same size as punctures on pronotal disc and separated by about twice their diameters. Declivity abruptly curved in profile. Elevated crest at elytral apex well developed, extending at least to interstriae 5. Striae and interstriae indistinct on declivity, but short, yellow setae present on odd-numbered interstriae. Interstriae 1 elevated, with very weakly developed granules. Interstriae 2 impressed, very narrow on declivital face. Interstriae 3 elevated, with contiguous, pointed granules, giving a serrate impression, strongly curving towards declivital suture in middle, curving outwards again towards apex, serrate elevation not reaching bottom 1/3 of declivity. Much smaller granules irregularly spaced exterior to interstriae 7, on face of declivity and posterior portion of elytral disc.

Male. Unknown.

Type material. Holotype female. Mexico: Chiapas, 11 km NE San Cristobal, Hwy. 199, 2438 m, 28-V-1987, black light plus mercury vapor, D.A. Rider and E.G. Riley. ( USNM). This specimen was originally in the Louisiana State Arthropod Museum.

Etymology. The name is chosen for the prominent curved crest on the elytral declivity and the prominent pointed granules on other elytral interstriae.

Figures

Figure 4. Species of Corthylus with acute spines on declivity or with interstriae 3 curved and serrate (2 of 2). A, B) C. cristatus new species, holotype. C, D) C. cristatulus new species, holotype. E, F) C. granulocristatus new species, holotype. G, H) C. poblanus new species, holotype. All photographs by the author.

Figure 7. Corthylus granulocristatus, new species, female holotype. A) Dorsal habitus. B) Lateral habitus. C) Frons and antenna. D) Declivity. All photographs by the author.