Ischnocnemis glabra Chemsak and Linsley, 1988

Eya, Bryan K., 2024, Revision of trachyderines related to Sphaenothecus from North America with description of three new genera, and new species of Lophalia Casey, 1912, Mannophorus LeConte, 1854, and Ischnocnemis Thomson, 1864 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini), Insecta Mundi 2024 (61), pp. 1-94 : 66-67

Ischnocnemis glabra Chemsak and Linsley, 1988

( Fig. 346–358 )

Ischnocnemis glabra Chemsak and Linsley 1988: 132 ; Chemsak et al. 1992: 83 (cat.); Chemsak and Noguera 1993: 63 (dist.); Monné 1994: 64 (cat.); Monné and Giesbert 1994: 146 (cat.); Noguera and Chemsak 1996: 402 (dist.)

Materials examined. MEXICO: Jalisco: 8 km NW Melaque , 16/ 23 Oct. 1986, J.A. Chemsak (holotype male, seven paratype males, and two paratype females, EMEC) ; Estación de Biología Chamela , 15 Oct. 1986, J.D. McCarty (1 paratype male, EMEC) ; 8 km NW Melaque , HWY 200, 13 Oct. 1992, J.D. Mc Carty (1 female, EMEC) .

Discussion. Ischnocnemis glabra Chemsak and Linsley is “moderate sized (13–16 mm), elongate and slightly tapered posteriorly” ( Chemsak and Linsley 1988: 132). The “integument is black with a vague metallic caste.” There are three costae on each elytron, a prominently elevated ivory subsutural costa extending from base to apical tenth attenuating apically, a narrow submarginal infuscate ivory costa starting slightly below humerus attaining apical fifth, and a narrow dark costa on the outside margin of the subsutural costa ( Fig. 357 ). The pubescence is obsolete (or opaque and minute). The front is confluently punctate, and the vertex is deeply contiguously punctate ( Fig. 350–352 ). The “antennal tubercles are moderately produced,” and antennae extend “about two 1.0), “side broadly rounded,” and disc is “finely, densely punctate, and usually with a glabrous spot slightly behind the middle” ( Fig. 353 ). The sternum is black, nitid, and glabrate with pubescence very short. The “elytra are three times longer than” wide (L/W: 3.1) with “punctures between costae moderately coarse and dense,” and between submarginal costae and epipleural margin “finer and denser.” The pubescence on elytra are obsolete, and elytral apices are sinuate truncate or “obliquely serrate-truncate with margins dentate” ( Fig. 355–356 ). The metatarsomere I is elongate and longer than tarsomeres II and III combined in this species ( Fig. 358 ).

“This species differs from most other Ischnocnemis presently included in this genus by the” black glabrate integument with brighter “yellowish vittae of the elytra” ( Chemsak and Linsley 1988: 133), and the overall, more glabrous appearance that is more reminiscent of Lophalia than Ischnocnemis . According to Chemsak and Linsley, “the type series is uniform in coloration and only the submarginal costa of each elytron shows any variation” where the base is usually yellowish. In some specimens the submarginal costae are mostly dark and just vaguely yellowish.

Figures

Figures 346–358. Ischnocnemis glabra Chemsak and Linsley, dorsal and lateral images: 346–347) Male, 14 mm, 8 km NW Melaque, Jalisco, MEX. 348–349) Female, 14 mm, Chamela, Jalisco, MEX. Head: 350–352) Front subvertical, mandibles retracted, dorsal half of genae narrow, base of mandibles almost contiguous with anterior margins of eye lobes (red arrow). Pronotum: 353) Disc with sides broadly rounded, apical margin without collar-like projection on sides, pubescence obsolete (very short). Thorax lateral image: 354) Pronotal disc convex, mesosternal process non-protuberant (red arrow). Elytra: 355) Male with apices sinuate truncate with margins dentate. 356) Female with apices obliquely serrate-truncate with margins dentate. 357) Each elytron with elevated, yellowish, glabrous subsutural costa (red arrow), vaguely yellowish submarginal costa starting slightly below humerus (green arrow), and another narrow glabrous costa (yellow arrow). Metatarsi: 358) Metatarsomere 1 (T1) longer (red brackets) than tarsomeres 2+3 (T2+3), T1/ T2+3: 1.3.