A small family of tiny beetles (12 British species in 5 genera). They are easily recognised as corylophids; they look like miniscule coccinellids (to which they are closely related) but are no longer than 1.3 mm. Coccinellids range in size from 1.0 mm up to about 10 mm.
They are not a popular family but I am quite fond of them, possibly as a result of a stroke of luck soon after I took an interest in them. In September 2005, during a survey of Poole Harbour, Dorset, I found an unusually large corylophid (1.3 mm; none of the others get much above 1.0 mm) which turned out to be the first British record of Rypobius praetermissus for 74 years (Telfer, 2006)!
Four of the British Orthoperus are associated with fungal decay of wood and may be found on fungal fruiting bodies, under bark, etc. Two of these are regarded as saproxylic species and are included in the Saproxylic Quality Index (SQI). Other habitats used by corylophids include grass heaps, compost heaps, litter piles in marshes, salt-marsh debris and bare, disturbed ground. Bowestead (2006) gives a useful summary of the habitat and microhabitat of each species in A Coleopterists’ Handbook.
To identify British corylophids, you really need to get a copy of Stan Bowestead’s (1999) revision of the family. It is superbly illustrated.
In recent years, Sericoderus brevicornis has been added to the British list and the identification of Sericoderus has become quite problematic. Download this:
Key to British Sericoderus (version 1: 2012-01-27).
Note (7th December 2013): I’m much more confident now of being able to identify the two Sericoderus species on external characters alone, lateralis being smaller and darker than brevicornis among other characters. So I ought to prepare an updated key to Sericoderus.
Sericoderus brevicornis was added to the British list by Galsworthy and Booth (2007) from a flight interception trap in woodland at Laleham, Middlesex with the first record in the period 6-13.v.2006. I believe Roger has subsequently seen British specimens going back to the late 1990s. But from recent discoveries in Germany (prompted by the key on this website!) it looks like S. brevicornis may have been present on the continent for as much as 20 years before it was first collected in Britain.
Keith Alexander has published what is only the third published British record of S. brevicornis, from the Isle of Wight in 2012 (Alexander, 2013). It makes me think I ought to publish more of my own records which now cover a large part of southern and eastern England, as the following map shows.
For identification of Orthoperus, the following table is a good starting point, before referring to Bowestead’s key:
|Elytral asperities?||Body length (mm)||Other features||Species||Conservation status, distribution and habitat notes|
|Asperities on elytra||0.90 – 1.03||elongate-oval||brunnipes||RDB3. Fen species.|
|Asperities on elytra||0.68 – 0.89||broadly oval||nigrescens||Nationally Scarce (Nb) but actually the commonest Orthoperus.|
|No asperities on elytra||0.80 – 0.99||♂ with obvious depression on metasternum and pimple very close to hind margin.||corticalis||Common. Long known as O. mundus (e.g. in SQI list where scores 4). Ancient woodland, typically assoc. with brackets or fungal hyphae under bark, etc.|
|No asperities on elytra||0.86 – 1.01||♂ without depression on metasternum. Elytral microsculpture (near scutellum) of transverse wavy lines.||atomus||Uncommon. Commoner in northern Britain? Mouldy stuff: pine needles, logs, etc.|
|No asperities on elytra||0.63 – 0.77||♂ without depression on metasternum. Elytral microsculpture (near scutellum) of isodiametric meshes.||aequalis||Common (has no conservation status); accidentally given RDBK by Hyman & Parsons (1992) but corrected by H&P (1994). SQI species (score 16). Typically under bark or on logs.|
|No asperities on elytra||0.56 – 0.77||Unicolourous pale testaceous.||atomarius||Very rare, synanthropic. Mainly recorded from wine cellars.|
Tony Allen and Andrew Duff (Allen and Duff, 2013) discovered a corylophid new to Britain in the New Forest on 21st May 2013: Arthrolips obscura.
Alexander, K.N.A. (2013). Sericoderus brevicornis Matthews (Corylophidae) on the Isle of Wight (VC 10). The Coleopterist, 22, 70.
Allen, A.J. and Duff, A.G. (2013). Arthrolips obscura (Sahlberg, C.R., 1833) (Corylophidae) new to Britain. The Coleopterist, 22, 62 – 64.
Bowestead, S. (1999). A revision of the Corylophidae (Coleoptera) of the West Palaearctic Region. Geneva: Muséum d’histoire naturelle, Genève.
Bowestead, S. (2006). Corylophidae. Pp. 103 – 105 in Cooter, J. and Barclay, M. (eds). A coleopterist’s handbook. 4th edition. Orpington: The Amateur Entomologists’ Society.
Galsworthy, A.C. and Booth, R.G. (2007). Pp. 181 – 182 in Hodge, P.J. (ed.) Coleoptera. [Report of the British Entomological and Natural History Society Annual Exhibition, London, 11th November 2006]. Journal of British entomology and natural history, 20, 179 – 191.
Hyman, P.S. (revised Parsons, M.S.) (1992). A review of the scarce and threatened Coleoptera of Great Britain. Part 1. U.K. Nature Conservation: 3. Peterborough: Joint Nature Conservation Committee.
Hyman, P.S. (revised Parsons, M.S.) (1994). A review of the scarce and threatened Coleoptera of Great Britain. Part 2. U.K. Nature Conservation: 12. Peterborough: Joint Nature Conservation Committee.
Telfer, M. G. (2006). Rypobius praetermissus Bowestead (Corylophidae) in Dorset. The Coleopterist, 15: 77 – 78.