Sericomyrmex radioheadi

Known only from the type collection. No biological details of the species are known. General details about the biology of the genus are given here.

Identification
Ješovnik & Schultz (2017) - Medium-sized species; mandible dorsally smooth; frontal lobe triangular, narrow, directed anterad; antenna long, antennal scape reaching posterior cephalic corner; posterior cephalic emargination deep; lateral mesonotal tubercles sharp and long; first gastral tergite with lateral carinae distinct, dorsal carinae faint or absent.

The body color of S. radioheadi is evenly light yellow, lighter than in other Sericomyrmex species. Only dried, pinned specimens were available for this species, however, so the pale color may be due to age. Morphology indicates that S. radioheadi is the sister species to Sericomyrmex bondari, with which it shares a similar head shape, smooth mandibles, and sharp mesonotal tubercles. S. bondari can be separated from radioheadi by its larger body size, shorter scape, and shorter and blunter lateral mesonotal tubercles, and by the presence of at least some thick black hairs.

Distribution
Known from an Amazonian Venezuela type collection.

Distribution based on Regional Taxon Lists
Neotropical Region: Venezuela.

Worker
Jesovnik and Schultz 2017. Figure 52. S. radioheadi worker (USNMENT00924061), SEM images. a Head, full-face view b mandibles c eye d mesosoma and metasoma, lateral view e mesosoma(detail), lateral view f propodeum and metasoma, anterolateral view.

Nomenclature

 *  radioheadi. Sericomyrmex radioheadi Ješovnik & Schultz, 2017a: 86, figs. 51, 52 (w.) VENEZUELA.

Worker
(holotype): HWe 1–1.08 (1.02) HW 1–1.08 (1.04) HW1 0.93–1 (1) HW2 1.08–1.15 (1.1) HW3 0.64–0.73 (0.72) IFW1 0.61–0.66 (0.62) IFW2 0.24–0.27 (0.24) HL1 1–1.08 (1) HL2 0.84–0.9 (0.88) SL 0.75–0.84 (0.8) EL 0.15–0.18 (0.15) Om 9–12 (9) WL 1.35–1.43 (1.36) PL 0.24–0.34 (0.29) PPL 0.2–0.25 (0.25) GL 0.92–1.02 (0.93) HFL 1.18–1.3 (1.25) PW 0.64–0.75 (0.65) CI 98–103 (102) FLI 59–62 (61) SI 75–82 (78) OI 15–18 (15) CEI 12–17 (12) [N=9]

Pilosity. Pubescence dense, appressed to decumbent, light yellow. Hairs curved, darker in color at base, yellow to gray, appressed to suberect, mostly decumbent.

Head. In full-face view evenly broad and long (CI=101 ± 2), posterior corner acute, posterior cephalic emargination deep (CEI=14 ± 2), gradually impressed. Vertexal impression distinct, frontal tumuli barely visible. Mandible with 7–8 teeth, dorsally smooth and glossy, finely transversely striate only along masticatory margin, striation sometimes faint. Eye medium-sized (OI =16 ± 1), mildly convex, without white layer, 9–12 ommatidia across largest diameter. Frontal lobe triangular, narrow (FLI=61 ± 1), posterior margin shorter than medial, lateral margin long, sometimes mildly convex. Frontal carina straight to slightly curved laterally, complete, reaching posterior cephalic corner. Antennal scape long (SI=77 ± 2), reaching posterior cephalic corners.

Mesosoma. Lateral pronotal tubercles short, lateral mesonotal tubercles sharp and long (Figure 51d, 52e); posterior mesonotal tubercles low and obtuse. Propodeal carinae faint, with distinct posterodorsal denticles.

Metasoma. Petiole with two low dorsal denticles; postpetiole with four low, short carina, two dorsal and two lateral, lateral pair faint. First gastral tergite with lateral carinae distinct, dorsal carinae absent or faint.

Type Material
Holotype worker: Venezuela, Amazonas, 10 km N of San Carlos de Río Negro, [2.0164, -67.0599] Jul-Aug 1978, K. Clark (: 1w, USNMENT00924059). Paratypes: same data as holotype (: 2 w: USNMENT00924060; 2w, USNMENT00924063) (: 2w, USNMENT00924061) (: 2w, USNMENT00924062).

Etymology
This species is named after the English rock band Radiohead as an acknowledgement of their longstanding efforts in environmental activism, especially in raising climate-change awareness, and in honor of their music, which is an excellent companion during long hours at the microscope while conducting taxonomic revisions of ants. The species name is a masculine noun in the genitive case.