Crpyptophagus denticulatus

This turned up in my moth trap. I keyed it using Duff and got to dentatus/denticulatus fairly confidently, though there were a couple of slightly tricky couplets. Antennal segment 9 was 0.86x the width of segment 10, which to my mind is hardly "nearly as wide as" (but was categorically wrong for the alternative, "not more than two thirds as wide". The pronotal callus was about 1/5 the length of the pronotum side but that depends on how you measure it, and the beetle was more-or-less exactly 2.0mm - borderline but just about one way rather than the other at couplet 3. Then the elytral pubescence was a little tough to call - the hairs at the side were more than "slightly longer recumbent or suberect" but nearly all (but not quite all) decumbent on the disc of the elytra.

I wasn't completely confident and in any case it looked like I needed to check the genitalia to confidently tell whether it was dentatus or denticulatus. Fortunately it was a male, otherwise I think I would have had to leave it unidentified. I did a poor job of the dissection (breaking one of the parameres in the process) but I could see enough detail to confirm it was denticulatus.

male Crpyptophagus denticulatus showing pronotum, head, fore tibia, antenna, elytra hairs (side and dorsal), aedeagus (preputial sac, ductal clamps and parameres), North Elmham (Norfolk, UK), 15th September 2023