Corthylus poblanus 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 : 12

Corthylus poblanus Atkinson , new species

Fig. 4 , G, H; Fig. 8 A–D

Diagnosis. This species resembles C. cristatus , C. cristatulus , and C. granulocristatus except that the tubercles on declivital interstriae 3 are separated at their bases and do not form a serrate crest. It resembles C. senticosus but is much larger and has a different arrangement of tubercles on the declivity.

Female. Unknown.

Male. Length: 2.0 mm, maximum width: 0.79 mm; length of elytra: 1.16 mm; length to width: 2.5; elytral length/ total length: 0.58; elytral length/width: 1.47. (n = 1).

Frons evenly concave from epistoma to vertex. Entire visible surface coarsely, sparsely punctate. Antenna slightly asymmetrical, 1 st and 2 nd sutures indicated by external grooves, 1 st septate.

Anterior margin of pronotum broadly rounded, with a pair of asperities at center. Asperities on anterior slope coarse, elevated, weakly developed, obsolete at summit. Pronotal disc shining, with, deep punctures, separated by about 2× their diameters, each associated with a short recumbent seta, about length of spacing between punctures. These punctures in center of disc associated with very faint transverse lines.

Striae and clearly marked on disc by shallow puncture; interstrial punctures less pronounced. 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 yellow setae present on odd-numbered interstriae, their length subequal to distance between striae. Declivity sulcate. Interstriae 1 slightly elevated, without granules. Interstriae 2 impressed, very narrow on declivital face. Interstriae 3 with contiguous, granules, strongly curving towards declivital suture in middle, curving outwards again towards apex, row of tubercles almost reaching apex. Much smaller granules irregularly spaced on interstriae 5 and 7, on face of declivity.

Type material. Holotype male: Mexico: Puebla, Mpio. Tetela de Ocampo, Huerto Don Lucas , 19.5313 N, 97.4834 W, 10-V-2018, 1,701 m ( CNIN).

Etymology. The name is based on the Spanish word, poblano, a resident of the state of Puebla.

Species with truncate elytral declivity

Fig. 9 , 10

Currently ten species of Corthylus are known from Mexico and Central America with a strongly truncate elytral declivity bordered by a raised, circumdeclivital ring. Three of these are described below. These species would key to couplet 50 in Wood’s 1982 key and to couplet 110 in Wood’s 2007 key along with 7 other previously described species (Figs. 9,10). While these can be distinguished by characters of the female frons, most specimens collected in traps are males. All can be distinguished by overall size, proportions, details of the circumdeclivital ring. Some diagnostic characters of these 10 species are summarized in Table 1 . The degree of “completeness” of the raised circumdeclivital ring varies from 100% ( C. eichhoffi Schedl , C. praeustus Schedl ) to 50% ( C. mexicanus Schedl ). In other species the upper portion of the ring is not complete near the sutural line ( C. concisus Wood , C. ibarrai new species). The overall body proportions vary from 2.8× length/width ( C. petilus Wood ) to 2.1 ( C. procerus Bright ).

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 8. Corthylus poblanus, new species, male holotype. A) Dorsal habitus. B) Lateral habitus. C) Frons and antenna. D) Declivity. All photographs by the author.

Figure 9. Mexican and Central American species with truncate declivity (1 of 2). A, B) C. ibarrai new species, holotype. C, D) Holotype, C. serratus Wood. E, F) C. latisetosus new species, holotype. G, H) C. burgosi new species, holotype. I, J) C. mexicanus Schedl. Photographs A–B, E–J by the author, C–D by S.M. Smith (Copyright National Museum of Natural History, Smithsonian Institution, Washington, D.C., published by permission).

Figure 10. Mexican and Central American species with truncate declivity (2 of 2). A, B) C. praeustus Schedl. C, D) Holotype, C. eichhoffi Schedl. E, F) Holotype, C. concisus Wood. G, H) C. procerus Bright. I, J) C. petilus Wood. Photographs A–D, G–J by the author. E–F by S.M. Smith Copyright National Museum of Natural History, Smithsonian Institution, Washington, D.C., published by permission).