Length: beetle in the photo 4.2 mm
The erector of subfamily Cillaeinae (Kirejtshuk 1986) gave this description of the group:
Body flattened and frequently strongly elongate, or convex and filiform; sides explanate, usually widely so. Labrum usually shallowly emarginate apically, sometimes bilobed. Antenna with 2- or 3-segmented club. Pygidium and 1-3 preceding tergites exposed beyond elytra. Tergal fimbriae large and well marked, at least on pygidium, or not visible (in filiform species). Anal sclerite never turned downward and last sternite not modified. Tegmen not bilobed, flattened. Penis trunk usually well sclerotized, flattened, short.
Brachypeplus is a genus of at least 17 species. On-line records show distribution in North and South America and in Asia.
Photo data: 6 February 2021. A number of these beetles were feeding between two rotting papayas that were lying on the ground. Soufrière, Dominica, Lesser Antilles.
Determined by Andrew Cline, California Department of Food & Agriculture. Dr. Cline notes the beetles shown here look like Brachypeplus anceps, but he also notes that several species closely resemble B. anceps.