Ambrosiodmus spinosus new species Pérez, Pérez-De la Cruz & Equihua

(Figs 1–4)

Diagnosis. This species is similar to A. obliquus in size and coloration, but the declivital impression is much deeper, the spines on interstriae 2 are much larger, more acute and similar to those on interstriae 1 and 3. The body is smaller and more robust.

Female: Total length 2.1–2.2 mm, elytra 1.28 mm long, length pronotum 0.91 mm, width 0.98 mm, body robust, color dark brown to black, uniform on the entire body.

Frons strongly reticulate with a small, smooth, longitudinal carina between the eyes; granules and punctures widely spaced, dispersed setae principally between the eyes; a tuft of abundant setae above epistomal margin. Antennal club slightly longer than scape; anterior face with two visible straight sutures; first two segments corneous, the third pubescent; posterior face with two visible sutures (type 2 of Hulcr et al 2007).

Pronotum quadrate, as wide as long. Anterior margin slightly procurved, unarmed. Asperities abundant on entire pronotum, arranged concentrically around the summit. Posterior surface finely asperate, abundantly reticulate to lateral areas.

Elytra straight, parallel-sided; disc occupying approximately 60% of total length. Striae not impressed, punctures small and shallow, arranged in definite rows, each with a small, straight, recumbent seta. Interstrial punctures slightly smaller than those of striae, erect setae much longer and thicker than those on striae. Interstriae 2−3 times as wide as striae.

Declivity flattened, steep, occupying 40% of elytral length. Striae with punctures and vestiture similar to that of disc. Interstriae 2 strongly impressed. All interstriae with numerous uniseriate acute granules, those on interstriae 2 less abundant. Interstrial setae slightly longer than those on disc. Posterolateral margin of declivity elevated, with a carinate border from interstriae 7 to suture.

Male: Unknown.

Type Material. Holotype, female: MÉXICO: Tabasco, Macuspana, Área Natural Protegida Parque Estatal Cascadas de Agua Blanca; 17.616838°, -92.473313°, 145m; 31/VIII/2012; T. de alcohol; Col. M. Pérez De la Cruz (CNIN). Paratypes (8 females); Tabasco, Teapa, Área Natural Protegida Monumento Natural Grutas de Coconá; 17.563968°, -92.928378°, 55 m; 15/VIII/2012, T. de alcohol; Col. M. Pérez De la Cruz (1, CIUT); Chiapas, Cacahoatán, Finca La alianza; 11/IV/2018, 9/V/2018, 13/VI/2018, T. de alcohol; Col. J. Barrera (CUIT, 2,; CEAM, 1, CNIN, 1; USNM, 1; UTIC, 1); Tapachula, Finca La Esperanza; 11/X/2017, T. de alcohol; Col. J. Barrera (CEAM, 1); 500 m antes Metzabok, Ocosingo, 8/X/ 2019, 588 m, 17.1278, -91.7656, A. Burgos Solorio, ABS 2929 (UAEM, 1).

Biology. Most specimens were collected in traps baited with ethyl alcohol so no information is known about hosts. Presumably its habits are typical of the genus.

Hosts. Unknown.

Etymology. The name is based on the abundant acute teeth on most declivital interstriae, unique among Mexican and Mesoamerican congeners.