Cicindelidia aeneicollis (Bates, 1881)

Duran, Daniel P., Shetterly, John A. & Vogtsberger, Roy C., 2024, Redescription of the tiger beetle Cicindelidia aeneicollis (Bates 1881) (Coleoptera: Cicindelidae) and discovery of new morphological variants from the Pacific Slope of Mexico, Zootaxa 5406 (2), pp. 383-389 : 384-388

Cicindelidia aeneicollis

is morphologically distinct from all other North and Central American species, possessing a unique set of characters. It bears setae on the pro-trochanters, but lacks setae on the meso-trochanters, a combination that is found in only Jundlandia Duran & Gough, 2022 , Brasiella Rivalier, 1954 and one other Cicindelidia species, Ci. cyaniventris (Chevrolat, 1834) . The proepisternum is polychromatic, transitioning basally to apically from blue to green, gold, red then a brassy-bronze color for the distal half to three quarters of the disk.

No other Cicindelidia is similar enough to be confused with Ci. aeneicollis , but more moderately maculated individuals bear resemblance to Brasiella praecisa (Bates, 1890) which also possesses setae on the pro-trochanter but not the meso-trochanter. The differences are described below.

Cicindelidia aeneicollis possesses prominent green subsutural foveae ( Fig 1 ) that contrast with the rest of the elytra and this trait is missing from B. praecisa . Cicindelidia aeneicollis lacks prominent dark infuscations that are visible in B. praecisa .

The proepisternum of Ci. aeneicollis is polychromatic ( Fig 2 ), transitioning from polished blue posteriorly, blending to green, gold, red and then brassy-cupreous anteriorly for the majority of the surface, as compared to the uniformly dark bronze proepisternum in B. praecisa .

Prominent elytral microserrations are present in Ci. aeneicollis ( Fig 3 ) and missing from B. praecisa .

Description. Medium-sized Cicindelidia . Body length 8.6–10.1 mm ♀ mean 9.5 mm, ♂ mean 9.2. Head ( Fig 4 ) slightly wider than pronotum, width 2.4–2.7 mm, mean ♀ 2.5, vertex dark cupreous with bright brassy and green highlights, especially in supraorbital region; frons brassy in middle, blending to metallic green and blue laterally; frons glabrous; two supraorbital setae present near each eye. Frons slightly convex, clearly delimited from clypeus, gradually blending into vertex. Frons surface with distinct longitudinal striae especially in lateral areas bordering eyes. Genae predominantly bright polished green to blue, brassy in some areas near margins, with deep longitudinal striae abruptly ending at border of vertex. Clypeus color ranging from cupreous to green, blending to other metallic colors along margins, irregularly wrinkled to finely vermiculate.

Labrum with 6–11 setae, ochre-yellow to pale yellow with thin dark brown to black border; labrum unidentate, length 0.6–0.8 mm, width 0.9–1.2 mm. Mandibles medium-sized, ochraceous, dark testaceous along edges. Maxillary palpi ochre-yellow with a darker metallic green to violet apical segment. Labial palpi colored similarly to maxillary palpi.

Antennae of normal length, reaching humerus to basal third of elytra, scape dark testaceous with metallic reflections of cupreous, gold, and violet, with a single subapical seta; pedicel dark testaceous with metallic reflections similar to scape, lacking any setae; flagellum antennomeres 3‒4 dark testaceous with metallic cupreous and violet reflections, with ring of apical setae and additional sparse setae throughout, antennomeres 5‒11 ochre-brown, dulltextured without metallic reflections and possessing erect setae in apical rings only, covered with fine pubescence throughout.

Pronotum 1.7–2.0 mm wide, length 1.7–2.1 mm, dark bronze, white setae present along lateral areas of dorsal surface; disc finely rugose with thin but distinct median line and strongly impressed anterior and posterior sulci; sulci often with faint to distinct green-blue metallic reflections; notopleural sutures clearly defined, not visible from dorsal view; proepisternum ( Fig 2 ) polished blue posteriorly, blending to green, gold, red and then purple anteriorly for over half of the surface, scattered setae sometimes present on disk surface.

Elytra elongate, 5.6–6.1 mm length, ♀ mean 5.8 mm; sutural spine small, microserrations present on elytral apices ( Fig 3 ); elytral dorsal texture granulate-punctate throughout; prominent subsutural foveae present and possessing metallic green reflections. Elytral coloration typically brown with reddish or greenish-coppery tones present, with fine green punctures throughout, visible under magnification. All of the individuals found at some sites in Guerrero, Oaxaca, and Chiapas are significantly darker and may range from dark brown to almost black with reduced or no maculation. For most of the more than 500 specimens examined from other sites, however, elytral maculations are typically present, usually consisting of a subhumeral spot, complete middle band that does not meet the lateral margin, subapical spot and connected apical lunule. In other populations green individuals may exist as a percentage of the population, approaching 40%. Considerable variation exists in the extent of the maculations ( Fig 5 ). In some specimens, the subhumeral spot connects to the middle band and the subapical spot may extend anteriorly. In other populations, individuals may be nearly to completely immaculate, especially in areas where darker forms occur.

Pro-coxae, meso-coxae, and meta-coxae dark metallic green to blue-violet, setae present throughout; pro-trochanters with a single subapical seta, mesotrochanters without a subapical seta; femora dark metallic bronze with violet and green reflections, femoral surface with rows of erect white setae dorsally and ventrally; tibiae violet to dark cupreous with dark green reflections near the apices, clothed with white setae that are sparser and shorter than those of the femora; tarsi violet with blue reflections dorsally.

Abdominal ventrites 1‒6 with metallic blue, dark blue and violet reflections; white decumbent setae present mostly along lateral third of each ventrite.

Geographic distribution and habitat

While the known range of Ci. aeneicollis in Mexico is wide (Chihuahua, Guanajuato, Sonora, Sinaloa, Guerrero, Michoacán, Colima, Oaxaca, and Chiapas) all specimens were taken in rather similar situations away from water and often quite dry. The altitude ranged from 2,223 meters in Michoacán to sea level. Habitat types included dry clay, sandy, or gravelly trails in thorn scrub or with scattered Acacias; clay trails through oak woods and along edges of pastures; shady clay trails in coffee fincas; coarse sand and limestone roads; sandy clay in a shaded streambed; red clay trails through oak woods; clay and sandy soils of borrow pits, and bare patches in Mesquite grassland

Figures

FIGURE 1. Dorsal habitus of Cicindelidia aeneicollis from Mexico: Sinaloa: El Dorado.

FIGURE 2. Lateral habitus of Cicindelidia aeneicollis from Mexico: Sinaloa: El Dorado.

FIGURE 3. Elytral microserrations present on Cicindelidia aeneicollis from Mexico: Sinaloa: El Dorado.

FIGURE 4. Dorsal and frontal habitus of the head of Cicindelidia aeneicollis from Mexico: Sinaloa: El Dorado.

FIGURE 5. Variation in extent of elytral maculations of Cicindelidia aeneicollis from Mexico: Sinaloa: El Dorado.