Notaferrum n. gen. (Coleoptera: Ptinidae): the first known spider beetle associated with weaver ants Author Gearner, Olivia M. Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN 47904 (USA) ogearner @ purdue. edu (corresponding author) Author Philips, T. Keith Systematics and Evolution Laboratory, Department of Biology, Western Kentucky University, 1906 College Heights Blvd 11080, Bowling Green, KY, 42101 (USA) keith. philips @ wku. edu keith.philips@wku.edu text Zoosystema 2021 2021-01-19 43 2 29 36 journal article 8670 10.5252/zoosystema2021v43a2 68ca95c6-672d-4cd2-aba7-2361d03419d6 1638-9387 4464304 urn:lsid:zoobank.org:pub:4020746C-CC98-4D98-A750-D7626701D4EA Genus Notaferrum n. gen. urn:lsid:zoobank.org:act: A9D794F8-7079-4544-A08D-FCE368A035B5 TYPE SPECIES. — Ptinus natalensis Pic, 1906 by original designation. ETYMOLOGY. — Notaferrum n. gen. is derived from the Greek nota for back and the Latin ferrum for blade in reference to the longitudinal blade-like ridges on the pronotum. DIAGNOSIS. — This genus can be recognized by the pair of longitudinal blade-like ridges located medially on the pronotum as well as a transverse, flattened, and U-shape depression with sides diverging anteriorly at the basal 2/5 of the pronotum. GENERIC DESCRIPTION Body Small, length approximately 3.4 mm , elongate. Head Eyes convex, ovoid, slightly projecting, visible dorsally; vertex flat at middle; antennal fossae deep and distinct medially and ventrally, antennae long, filiform, 11 antennomeres; interantennal space between antennal insertions narrow, with a longitudinal groove; clypeus triangular, concave; labrum appearing truncate, maxillary and labial palpomeres fusiform. Pronotum Two thin longitudinal ridges positioned on either side of midline; two lateral tubercles on either side of the pronotum, flanking a transverse groove, basally forming a large posterior flat U-shaped depression with sides diverging anteriorly; anterior margin with deep irregular punctures. Elytra With longitudinal rows of punctures; interpuncture rows of small setae; scattered scale-like setae. Thoracic ventrites Proventrite small, about as long as wide; anteriorly, ventrally expanded to partially cover mouthparts, proventral process extending beyond procoxae, expanded anteriorly, tip truncate; mesoventrite U-shaped, surrounding proventral process apex, much wider than long, metaventrite large, wider than mesoventrite. Abdominal ventrites First three ventrites large, each as long or longer than 4th and 5th combined, fourth very short, fifth smaller than first three but much longer than fourth. Sutures visible between all ventrites; fifth ventrite distinctly transversely concave. Legs Femora expanded apically, tibia similar in length to femora; first tarsomere largest; metacoxae with posterior extension lateral to the trochanter; pro-, mesocoxae conical shaped, moderately projecting, metacoxae transverse, extending laterally to elytral margin. Sexual dimorphism Male antennomeres 6-11 distinctly more elongate than those of the female. Eye size in both sexes approximately equal.