Ischnocnemis similis Chemsak and Noguera, 1997

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 : 71-72

Ischnocnemis similis Chemsak and Noguera, 1997

( Fig. 382–395 )

Ischnocnemis similis Chemsak and Noguera 1997: 12 ; Monné and Hovore 2006: 144 (cat.); Ordóñez-Reséndiz and Martinez-Ramos 2017: 828 (dist.).

Materials examined. MEXICO: Jalisco: 14 km NE of San Gabriel, 1920 m, 9 Nov. 1995, Chemsak and Katsura (holotype male, allotype female, EMEC; paratypes: 1 male, 1 female, BKEC). Eighteen paratypes, all from MEXICO: Jalisco: Puerto Los Mazos, Sierra de Manantlán , 24 Oct. 1995, B.K. Eya (3 males, 1 female, BKEC), 27 Oct. 1995, B.K. Eya (3 males, BKEC), 22 Oct. 1996, B.K. Eya (2 males, BKEC) ; Microondas Puerto Los Mazos, Sierra arrow). 395) Metatarsi with tarsomere 1 (T 1) longer (red brackets) than tarsomeres 2+3 (T 2+3), T 1 / T 2+3: 1.2.

de Manantlán , 16 Oct. 1996, B.K. Eya (1 male, 1 female, BKEC), 21 Oct. 1996, B.K. Eya (2 males, BKEC) ; 5.4 km NE San Gabriel, Hwy 432, 17 Oct. 1996, B.K. Eya (1 female, BKEC) ; 19.2 km N San Gabriel, Jct. 80/432, 28 Oct. 1995, B.K. Eya (2 males, BKEC) ; 20.9 km N San Gabriel, Jct. 80/432, 28 Oct. 1995, B.K. Eya (2 males, BKEC). Additional materials examined from Jalisco: 6 km W Autlán, 16/ 17 Oct. 2000, F.T. Hovore (4 males, 4 females, CASC) ; 15 km S Autlán 29 Sept. 1991 J.E. Wappes (1 female, FWSC) .

Discussion. Ischnocnemis similis Chemsak and Noguera is “moderate sized (11–16 mm), elongate and slightly tapered posteriorly” ( Chemsak and Noguera, 1997: 12). The integument is black, and the pubescence is sparse above, and pale, suberect and appressed underneath. There are four narrow eburneous costae on elytra, a subsutural pair “extending from base almost to apex, which are usually broader yellow along sides, and submarginal pair that are slightly narrower extending from the base at humeri to about apical one-tenth” ( Fig. 394 ). The integument along suture of elytra is broadly black. Front is subconfluently punctate, and sparsely pubescent ( Fig. 388–390 ), and “vertex is finely, densely punctate,” and sparsely clothed with long, erect setae. The “antennal tubercles are moderately produced.” The antennae are slender, “extending about three antennomeres beyond elytra” in males, and about an antennomere to one and a half antennomere longer in females. The pronotum is as long as broad (L/W: 0.92), sides broadly rounded with apex behind margin is “very narrowly impressed transversely, and base moderately broadly impressed at sides” ( Fig. 391 ). The disc of pronotum is “moderately, coarsely, densely, subconfluently punctate with an irregular, elongate, glabrous callus” in middle of basal half. The pronotum is clothed sparsely with short, depressed pubescence ( Fig. 392 ). Prosternum is transversely rugulose, clothed sparsely with pale, erect pubescence, and “meso- and metasternum are finely, densely punctate at sides” and glabrate in middle. The “elytra are about three times as long as broad” (L/W: 2.9) with “punctures fine, sparse, and well separated” near base becoming denser apically with “pubescence sparse, short and subdepressed.” The elytral apices are sinuate truncate or serrate truncate with exterior angles obtusely angulate or dentate ( Fig. 393 ). The metatarsomere I is elongate and longer than tarsomeres II and III combined ( Fig. 395 ).

According to Chemsak and Noguera (1997: 12), “this species is structurally very similar to I. costipennis Thomson ,” which is much larger in size with most individuals having a reddish abdomen and finer punctures. The elytra of I. costipennis differs by “having a vague longitudinal costa between the two elevated ones.” Ischnocnemis costipennis is usually sexually dichromatic, while in I. similis the sexes are more uniform in coloration. The vestiture underneath of I. costipennis is denser and appressed obscuring the surface of integument while the sternum of I. similis is sparsely clothed, and the integument unobscured and plainly visible. Ischnocnemis eyai is also similar in size and form to this species but can be distinguished by the denser, “transversely appressed golden pubescence on the pronotum, and by the vague longitudinal costa between two elevated ones” on elytra as found in I. costipennis ( Chemsak and Noguera 1997: 11–12) . The name similis refers to the similarity in overall appearance to I. costipennis .

Figures

Figures 382–395. Ischnocnemis similis Chemsak and Noguera, dorsal and lateral images: 382–383) Male, 16 mm, Puerto Los Mazos, Jalisco, MEX. 384–385) Male, 13 mm, 19.2 km N St. Gabriel, Jalisco, MEX. 386–387) Female, 15 mm, Puerto Los Mazos, Jalisco, MEX. Head: 388–390) Front vertical, mandibles retracted, and sides strongly angulated near base (blue arrow), dorsal half of genae narrow, base of mandibles almost contiguous with anterior margins of eye lobes (red arrow). Pronotum:391) Disc with sides broadly rounded, apical margin without collar-like projection on sides, integument glabrate, punctures fine, subconfluent, pubescence sparse, short, and depressed. Thorax lateral image: 392) Pronotal disc convex, mesosternal process non-protuberant (red arrow). Elytra: 393) Apices sinuate truncate with exterior angle dentate. 394) Each elytron with elevated, yellowish, subsutural costa (red arrow), and submarginal costa starting from base of humerus (green