AppearanceBeetles in the genus Cryptophilus are often confused with Cryptophagidae and are found on the same mouldy substrates, but differ in various structural elements, such as the shape of the antennae and the pronotum (as well as some ventral characters of legs/hips).
NamingFor the longest time this species would have been identified as Cryptophilus integer, but Esser (2016) found that this species was harbouring two separate distinguishable species. When studying the type of C. integer to see which of the two species should continue to carry the name integer, he found that the type of C. integer was in fact not a Cryptophilus, but conspecific with Micrambe abietis (Cryptophagidae), so the name integer had to be dropped for these altogether.
He split the two species previously known under the name "Cryptophilus integer" sensu auctorum into Cryptophilus propinquus and C. simplex, only to find out a year later (Esser, 2017) that the beetle previously known as Typhaea angusta was in fact a Cryptophilus and conspecific with C. simplex resulting in this species needing to be renamed to Cryptophilus angustus.
So the two species once known as Cryptophilus integer are now C. propinquus and C. angustus.
Some text fragments are auto parsed from Wikipedia.Esser, J. (2016) Über die Identität von Cryptophilus integer (Heer, 1841) (Coleoptera: Erotylidae). – Entomologische Nachrichten und Berichte 60(3/4), pp.213-218. (PDF)
Esser, J. (2017) On the Nearctic Cryptophilus Reitter, 1874 (Coleoptera: Erotylidae). – Linzer biologische Beiträge 49(2), pp.1133-1137. (PDF)
Esser, J. (2017) Was ist Typhaea angusta Rosenhauer 1856 (Coleoptera)? - Entomologische Nachrichten und Berichte, vol. 61(3/4), pp.177-179.