Corthylus cristatulus 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 : 9

Corthylus cristatulus Atkinson , new species

Fig. 4 C, D ; Fig. 6 A–D

Diagnosis. This species is distinguished from C. cristatus and C. granulocristatus by the smaller size and less pronounced crest of interstriae 3, and smaller, less closely spaced punctures on the elytra.

Female. Length: 2.46 mm, maximum width: 0.93 mm; length of elytra: 1.39 mm; length to width: 2.6; elytral length/total length: 0.57; elytral length/width: 1.49. (n = 4). Color dark black.

Frons evenly concave from epistoma to vertex. Lower surface of frons with widely spaced, low granules, each associated with a short seta. Setae sparse, more abundant on sides and upper portion of frons, marginal setae only slightly longer than those in center, not forming incurved margins, absent from lower frons. Area just above epistoma impunctate. Antenna slightly asymmetrical, 1 st and 2 nd sutures indicated by external grooves, 1 st partly septate. Cirrus absent, marginal setae on club sparse, short, less that ¼ length of club.

Anterior margin of pronotum broadly rounded, unarmed. First row of asperities posterior to margin suberect. Remaining asperities on anterior slope not elevated, weakly developed, obsolete at summit. Pronotal disc shining, with deep punctures, separated by about 3× their diameters.

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, partly obscured by deep confused punctures. 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, narrower 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 ½ of declivity. Much smaller granules irregularly spaced exterior to interstriae 3.

Male. Similar to female except for frons and antenna. Frons evenly convex, shining, with widely separated, deep punctures, vestiture absent. A weak transverse impression above epistoma. Antenna suboval, without longer, marginal setae.

Type material. Holotype female. Mexico: Veracruz, El Santuario , campus INECOL, 15-III-2015, bottle trap with ethanol, L.A. Ibarra ( CNIN) . Allotype male. Same data except 15-IX-2015 ( CNIN) . Paratypes. Same data except different collection dates (2015–2016) ( IEXA, 2, UTIC, 2, USNM, 2).

Etymology. The name is chosen for the prominent curved crest on the elytral declivity. This species is very similar to C. cristatus but smaller, hence the diminutive form of the name.

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