Microteroschema parvum Eya, 2024

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 : 78-80

Microteroschema parvum Eya , new species

( Fig. 428–439 )

Description. Male: Length 9–10 mm. Form small, stout, slightly tapering; integument black to dark brownish, each elytron with single, raised, broad, ivory subsutural vitta. Head small; vertex finely, subconfluently punctate with vaguely, raised, glabrous area along midline; front densely, confluently to irregularly punctate, frontoclypeal sulcus vague or absent; postclypeus triangular, subparallel with front, proximal third glabrate, sparsely punctate in middle with narrow transverse densely, finely punctate band below, distal margin glabrate and declivous to anteclypeus; antennal tubercles vaguely elevated, apices obtusely angulate; pubescence on vertex, front, postclypeus and antennal tubercles obscure, short, dark and erect; genae prominent with base of mandibles separated from anterior margins of lower eyes, integument sparsely, irregularly punctate, pubescence sparse, short, depressed; labrum dark reddish brown, finely, irregularly punctate, sparsely clothed with long, suberect, golden setae; antennae slender, exceeding elytra apices by an antennomere; scape conical, densely, rugosely, coarsely punctate, pubescence short, depressed, underside with few, long setae; antennomeres III–VI with dorsum carinate, rugosely punctate, pubescence, short, dark, depressed, remaining antennomeres opaque, minutely, densely punctate, densely clothed with minute, appressed, dark setae, apices with few, longer, depressed setae; antennomeres VI–X gradually flattened with apices angulate on sides, inside surface vaguely carinate; antennomere III longer than I; IV shorter than III, subequal to I; V longer than IV, shorter than III; VI and VII subequal to V; VIII shorter than VII, subequal to I; IX subequal VIII; X shorter than IX, XI subequal to III. Pronotum as long as wide (L/W: 1.0) sides slightly rounded; disc shallowly convex, punctures shallow and discrete, basal half with longitudinally glabrous area in middle; apical margin of dorsum unelevated and not constricted behind, apical margin of sides vaguely elevated and narrowly constricted behind; base slightly impressed on sides; pubescence obscure, short, suberect; proepisternal area shallowly punctate, pubescence short, erect; prosternum slightly concave, apical half transversely plicate, basal half densely, subcontiguously punctate in middle, each side above coxae with impressed, subrectangular, sparsely, coarsely punctate area, pubescence short, moderately dense, erect; mesosternum coarsely punctate, pubescence depressed, mesosternal intercoxal process as wide as coxal cavities; mesepisterna and mesepimera with punctures fine, dense, shallow, densely clothed with appressed short pubescence; metasternum coarsely, discretely punctate, punctures sparse in middle, finer and denser near base of mesocoxae, pubescence obscure, depressed; metepisterna densely clothed with appressed pubescence. Scutellum black, glabrate, punctures near base sparse, shallow, pubescence if present, obscure, sparse, short, appressed. Elytra 2.5 times as long as broad; each elytron with a broad, raised, glabrous, ivory subsutural vitta; punctures coarse and discrete from base to apices, epipleural margin with punctures smaller, denser, and subcontiguous; pubescence obscure, sparse, short and suberect; apices bi-emarginate to sinuate truncate with sutural and external angle dentate. Legs slender; femora coarsely, irregularly punctate, profemora with punctures finer and shallower, pubescence obscure, short, depressed; pro- and mesofemora slightly clavate; metafemora linear, slightly arcuate near base, shorter than body, attaining fourth abdominal segment; protibiae with punctures minute, inner surface densely clothed with short, depressed pubescence; meso- and metatibiae carinate, coarsely, rugosely striate-punctate, pubescence short, depressed; metatarsomere I shorter or subequal to tarsomeres II and III combined ( Fig. 438 ). Abdomen with punctures shallow, sparse in middle, finer and denser on sides and near base of metacoxae, pubescence sparse, golden, suberect in middle, denser, appressed on sides; apex of last sternite truncate.

Female: Length 11 mm. Form stouter than male, parallel sided. Antennae attaining elytral apices. Prosternum with basal half shallowly, striate-punctate above coxae, coarsely punctate in middle. Metatarsomeres shorter and broader than male ( Fig. 439 ). Abdomen with pubescence longer and suberect in middle; apex of last sternite broadly truncate.

Etymology. The name parvum refers to “small” in Latin due to the small size of this species.

Type material. Holotype, male, MEXICO: Chiapas, 15 km NW Ocozocoautla , 14 Sept. 1990, 800 m, P.G. da Silva, T. Eager, ex. Haematoxylon brasiletto ( EMEC 1327592 ) deposited in EMEC; allotype, female, MEXICO: Oaxaca, 36 km E Tapantepec, HWY 190, ca. Hospedaje Paty, 17 Oct. 2005, B.K. Eya ( BKEC). Six paratypes, all from MEXICO: Oaxaca: MX 190, 1.5 km W of Chiapas border, 21 Oct. 2001, F. Skillman, J. Davidson, microwave tower (1 male, 1 female, EMEC). Chiapas: El Aguacero, 16 km W Ocozocoautla, 5 Oct. 1986, E. Giesbert (1 female, FSCA); El Sumidero, nr. Tuxtla Gutierrez, 20 Oct. 1986, D. Thomas, E. Fischer (1 female, FSCA); Parque Aguacera, 27 Sept.–3 Oct. 1986, J. Wappes (1 male, 1 female, FSCA).

Discussion. Microteroschema parvum Eya new species can be distinguished by the combination of characters: (1) small and stout body form; (2) declivous front with divergent antennal tubercles ( Fig. 432–434 ); (3) single wide ivory subsutural vitta on each elytron; (4) genae with the margins of lower eyes well separated from base of mandible; (5) prominent and forward extending mandibles ( Fig. 433 ); (6) short antennae that does not exceed more than an antennomere beyond the elytral apices in male and just attaining apices in female; (7) carinate dorsum of antennomeres III–VI; (8) non-protuberant mesosternal process ( Fig. 436 ); (9) coarsely striate-punctate meso- and metatibiae; and (10) short metatarsomeres ( Fig. 438–439 ). Microteroschema parvum has all the characteristics of Lophalia Casey , which include subparallel form, glabrate and polished integument, and elytral apices with outer angles dentate; however, the mesosternal process is not protuberant, and the front is declivous with divergent antennal tubercles ( Fig. 432–434 ). Lophalia has a protuberant mesosternal process and a front that is subvertical. Ischnocnemis consists of species that are elongate in form with longer antennae, front that is vertical to subvertical with retracted mandibles, genae that are narrow with margins of lower eyes are almost contiguous with base of mandibles; and metatarsi that are narrow and elongate with first tarsomere longer or subequal to the following two tarsomeres combined.

Figures

Figures 428–439. Microteroschema parvum Eya, sp. nov., dorsal and lateral images: 428–429) Male, 9 mm, 13 km NW Ocozocoautla, Chiapas, MEX. 430–431) Female, 10 mm, 36 km E Tapantepec, Oaxaca, MEX. Head: 432–434) Front declivous, genae prominent, base of mandibles separated from anterior margin of lower eyes (red arrow), mandibles prominent extended forward. Pronotum: 435) Disc with sides shallowly rounded, apical margin unelevated, without collar-like projection on sides, integument black to dark brownish, and punctures shallow. Thorax lateral image: 436) Pronotal disc shallowly convex, mesosternal process non-protuberant (red arrow). Elytra: 437) Apices bi-emarginate truncate with sutural and exterior angle dentate. Metatarsi: 438) Male metatarsomeres short, tarsomere 1 (T1) subequal to or shorter (red brackets) than tarsomeres 2+3 (T2+3), T1/ T2+3: 0.88. 439) Female metatarsomeres shorter and broader than male, tarsomere 1 (T1) subequal to or shorter (red brackets) than tarsomeres 2+3 (T2+3), T1/ T2+3: 0.93.