are saproxylic and will need to be searched for among decaying wood, this group includes Atrecus affinis (Paykull, 1789), Astrapaeus ulmi (Rossi, 1790), Velleius dilatatus (Fabricius, 1787) and several Quedius Stephens, 1829 among others and many non-saproxylic species will also occur around wood, either attracted to decaying fungi or hiding under loose bark or under logs by day. Many will be found in coastal situations and some e.g. species of Cafius Curtis, 1829, are restricted to the seashore, among those found only in wetland habitats are species of Erichsonius Fauvel, 1874, and some e.g. the very common Xantholinus linearis (Olivier, 1795) are likely to occur in just about any situation. The nests of social-insects birds and mammals are also likely to host a few species and some e.g. Quedius longicornis Kraatz, 1857 which is associated with mole’s nests, or Q. brevis Erichson, 1840, which develops in ant-nests, rarely occur elsewhere.  For the general coleopterist it is unlikely that members of this subfamily will need to be searched for specifically as they will occur regularly with general searching and lots of species will be found when working compost, dung, decaying fungi and carrion. The habitats of some species will soon become familiar e.g. Philonthus decorus (Gravenhorst, 1902) will invariably occur under logs on damp soil devoid of vegetation in wooded situations, Creophilus maxillosus (Linnaeus, 1758) is often associated with carrion and Ontholestes marinus (Linnaeus, 1758) will often be found around dung.

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Classification

Rove beetles have never been generally popular with collectors because of problems with identification but this is no longer the case; Joy’s handbook was comprehensive in its day but the line-drawings belied how distinctive the present group is, the descriptions are often highly comparative and, except in the more obvious cases, lack sufficient definition, but with the publication of the Royal Society handbook these problems are negated. Furthermore there is a wealth of information and, in most cases, good photographs of the species are available online although a certain amount of caution is needed here. For those prepared to dissect specimens the group provides many instances of large sibling species that are easy to deal with and readily separated on genitalia characters. The following brief discussion is an attempt to put the UK fauna into perspective.

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Our fauna includes members of three tribes, all of which represent a small part of a much larger Holarctic or world distribution. In the first instance identification relies on the form of the lateral bead of the pronotum, this is either entirely lateral (lateral bead), or curves ventrally under the antero-lateral margin (ventral bead). The majority of genera have a ventral bead; those with a lateral bead include the Othiini Thomson, C.G., 1859 and the subtribe Quediina Kraatz, 1857 of the Staphylinini Latrielle, 1802. Quediina are distinguished from the Othiini in having the pronotum either devoid of larger punctures or having a small series, usually of  three, either side of the middle confined to the anterior half, in Othiini there is also a series of punctures either side of the middle but these continue onto the basal half. These distinguishing features will seem rather intricate at first but the groups are otherwise rather distinctive anyway and the various genera will quickly become familiar.

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• Othiini Thomson, C.G., 1859 includes six species in two genera. Atrecus affinis is a widespread saproxylic recognized by the form of the mandibles, the almost impunctate elytra and bicoloured abdomen. Species of Othius Thomson, C.G., 1859 have shorter and broader mandibles, strongly though rather sparsely punctured elytra and a more or less uniformly coloured abdomen. Othius lapidicola Märkel & Kiesenwetter, 1848 has been recorded only once in the UK; in 1979 from a Scottish mountain, but the rest are widespread and occur among litter etc. in a range of open situations; parkland, moorland and agricultural margins as well as woodland.

• Xantholinini Erichson, 1839 includes 8 UK genera and 21 species. They are easily distinguished by the ventral bead and elytra which overlap along the sutural margin. Again, they will become very distinctive with a little experience; they are mostly medium sized beetles, 3-14mm with most >5mm, very elongate, flat and parallel-sided with long temples, small eyes and geniculate antennae. A prominent character in most is the pair(s) of deep longitudinal furrows at the front of the head which are often valuable aids to generic identification. Many are widespread and at least some will soon be found by general sweeping or searching among organic detritus in a variety of situations. Species of Xantholinus Dejean, 1821 may be recognized by the size, >6mm, and rounded posterior margin of the head. X. linearis (Olivier, 1795) and X. longiventris Heer, 1839 are both widespread and in general our commonest members of the subfamily, they occur in a wide variety of situations and should soon be encountered by general surveying. X. tricolor (Fabricius, 1787) occurs sporadically and very rarely across central England and there are a few records from the Scottish Highlands but otherwise the species are widespread. The following two genera can be recognized by the paired furrows on the front of the head. Our four species of Leptacinus Erichson, 1839 are widespread but local; L. formecetorum is a myrmecophile while the others occur among decaying vegetation etc, and may be abundant in dung. They are distinguished by the size, 3.0-5.5mm, and the two longitudinal series of at least eight punctures on the pronotum. Our two species of Phacophallus Coiffait, 1956 are larger, 5.5-6.5mm, and have at most six punctures in each series on the pronotum. Both are immigrant species from warmer parts of the Old World; P. parumpunctatus (Gyllenhal, 1827) is long established, widespread and generally common among compost and dung heaps. P. pallidipennis (Motschulsky, 1858) is a more recent addition to our list and so far is a very local southern species. Our remaining genera have a single pair of furrows to the front of the head. Five species of Gyrohypnus Leach, 1819 occur in the UK, they are medium sized, 5.5-7.5mm and uniformly dark in colour - all our remaining genera have contrastingly pale elytra – with the head strongly and densely punctured. G. atratus (Heer, 1839) is a local myrmecophilous species of the south of England while G. wahneri (Scheerpeltz, 1926) is a recent addition known from only a few sites in the south, the remainder are widespread, locally common and associated with dung or other decaying organic matter. Gauropterus fulgidus (Fabricius, 1787), the only UK member of the genus, is distinguished by a sub-lateral pronotal groove. Among the largest of our species at 8-12mm, it is very local and generally rare, occurring in compost in the south of England and South Wales. At 10-14mm, Megalinus glabratus (Gravenhorst, 1802) is our largest member of the tribe and easily distinguished by its general habitus, it is locally common in Wales and southern England and more sporadic and generally rare to the far north of Scotland, typical habitat is open grassland. Our remaining species are medium sized, 6.5-8.0mm, with distinctly microsculptured forebody, both have longitudinal series of large punctures to the pronotum but in Nudobius Thomson C.G., 1860 it also has finer punctures throughout. Nudobius lentus (Gravenhorst, 1806) is a saproxylic species; it was formerly widespread in the northern Scottish highlands but in recent decades has become established across England and North Wales. Our single species of Hypnogyra Casey, 1906, H. angularis Ganglbauer, 1895, which is superficially similar to Nudobius but lacks the finer pronotal punctation, is a very local insect of southern England and the south Wales coast and like Nudobius is associated with decaying trees.

• STAPHYLININI Latreille, 1802. This is the largest of our tribes with 158 species of 23 genera included in five subtribes although the genera are listed below under the ‘traditional’ three subtribes for convenience.

  • QUEDIINA Kraatz, 1857 are distinguished among the tribe in having a lateral pronotal bead. More generally they may be recognized by the short series of larger punctures, usually three, confined to the anterior half of the pronotal disc although occasionally, as in Astrapaeus, they may be missing altogether.  Quedionuchus plagiatus Mannerheim, 1843, which until recently was included in a subgenus of Quedius, and Astrapaeus ulmi (Rossi, 1790) have recently (at least on the UK list) been incorporated into the subtribe TANYGNATHININA Reitter, 1909. The group is dominated by the large genus Quedius Stephens, 1829, with 45 species in 5 subgenera. Within the tribe, Quedius are distinguished by the dilated front tarsi, the microsculptured head capsule and the form of the maxillary palps where the terminal segment is longer than the penultimate. The subgenera of Quedius are easily distinguished on gross morphology e.g. the size of the eyes relative to the head, and many species are very distinctive but the group also includes many that will need to be examined very carefully or dissected. Many of the species are widespread and locally common and so a good variety should soon be recorded, many are generalists and occur among decaying organic matter of all kinds, including carrion and dung, and a good number are associated with decaying trees and nests, but some are more specific e.g. Q. nigrocaeruleus Fauvel, 1874 occurs in subterranean mammal nests and less often in those of social hymenoptera while Q. plagiatus Mannerheim, 1843 is almost always found under conifer bark. Others occur in wetland habitats and there are several with very restricted ranges e.g. Q. balticus Korge, 1960 occurs only in a few fens in the southeast while Q. simplicifrons Fairmaire, 1861 is restricted to coastal habitats in England and Wales. The very distinctive Velleius dilatatus (Fabricius, 1787), which should now more correctly be included in Quedius, is a saproxylic species which is likely to occur anywhere in England or Wales following the recent expansion in the range of its host, the hornet, Vespa crabro L. Astrapaeus ulmi (Rossi, 1790) differs from Quedius in lacking microsculpture to the head; it is a very local and rare species of the southeast coast, thought to be saproxylic. Heterothops Stephens, 1829 includes five UK species which have been included in a distinct subtribe, AMBLYOPININA Seevers, 1944, on the latest checklist; they are small; at most 5mm, with small eyes and the terminal segment of the maxillary palps diminutive. Members are ecologically diverse; they are associated with decaying plant material and underground nests and one, H. binotatus (Gravenhorst, 1802), is restricted to shores and saltmarshes. The following two species, each the only UK member of its genus, are distinguished among the subtribe in having the front tarsi normal i.e. not dilated. The smaller Acylophorus glaberrimus (Herbst, 1784), 6-8mm, is a very rare species restricted to wetland in the New Forest, while the smaller Euryporus picipes (Paykull, 1800), 9-10mm, occurs in Northern England and Scotland and is associated with moss and litter in damp situations.​

  • PHILONTHINA Kirby, 1837. All members have the ventral pronotal bead, which will distinguish them from the previous group, and from the following subtribe they may be distinguished by the mostly smaller size and the pronotal punctation which generally consists of two longitudinal series of larger punctures that extend onto the basal half although some species of Philonthus Stephens, 1829 lack these punctures completely. The group includes 80 species of 9 genera. With 46 species, Philonthus is the largest of our genera and, unlike Quedius, the majority are included in the nominate subgenus; only the very distinctive P. marginatus (Muller, O.F., 1764) is included in another; Onychophilonthus Neresheimer & Wagner, 1924, they do, however, fall into conveniently discrete groups based on the number of punctures in the pronotal series. Philonthus are morphologically very diverse, ranging in size from 5-13mm and showing great variation in the shape of the head and pronotum but, as with the group generally and in much the same way as with the Quediina, they soon become familiar. They are associated with decaying organic matter in almost any situation, and many species will quickly be found when working dung, carrion or compost. Some e.g. P. fumarius (Gravenhorst, 1806) or P. mannerheimi Fauvel, 1869 are restricted to wetland habitats and many have a restricted distribution, but many more are widespread and common and, unlike many members of Quedius, they are generally not associated with wood. Two genera are represented single species in the UK and both are restricted to coastal habitats; Rabigus pullus (Nordmann, 1837) is very local along the south coast of Wales, while Remus sericeus Holme, 1837 is more widespread around the coast of Wales and south Devon. The smallest member of the group and the only species of the genus to occur in the UK, Gabronthus thermarum (Aubé, 1850) is a very local insect occurring in compost in the southeast. Our seven species of Gabrius Stephens, 1829 are mostly wetland beetles although G. splendidulus (Gravenhorst, 1802) is a widespread and common saproxylic, and G. piliger Mulsant & Rey, 1876 occurs commonly in compost and dung. Our nine species of Bisnius Stephens, 1829 occur more generally among decaying vegetation and dung in most habitats and several may be found in mammal and bird nests; B. subuliformis (Gravenhorst, 1802) is almost always found arboreal nests and hollows. Bisnius scoticus (Joy & Tomlin, 1913) is restricted to the Scottish Highlands. Specimens of both genera are easily sampled and will usually occur in numbers, often with more than one species present, but in general they will need to be dissected for certain identification. Our three species of Erichsonius Fauvel, 1874 are also wetland insects but only E. cinerascens (Gravenhorst, 1802) is at all common. The exclusively coastal genus Cafius Curtis, 1829 includes three UK species; C. cicatricosus (Erichson, 1840) is a very local insect of the south coast but the others are more widespread; C. xantholoma (Gravenhorst, 1806) generally, and C. fucicola Curtis, 1830 mostly in the west.

  • STAPHYLININA Latreille, 1802. UK members of this group are all large, at least 10mm and the largest of all our staphs, Ocypus olens (Müller, O.F., 1764) is included, and coupled with the large size they all have the pronotum randomly punctured throughout except for, in some species, a median longitudinal smooth area. But they will very quickly become obvious from the general appearance; they are robust and rather parallel-sided with powerful mandibles and the posterior margin of the head variously angled. The front tarsi are dilated and the extent may differ between the sexes. Identification is generally straightforward and often possible by picture-matching although the occasional specimen may need to be dissected. All are predatory and associated with habitats with a high concentration of prey e.g. dung, decaying fungi, carrion and compost, most are active nocturnally and many can be found roaming pathways and lawns in search of prey, and by day they tend to remain hidden under debris or among litter Adults are long lived and overwinter among tussocks or in soil in sheltered situations such a hedgerows and headlands, they become active early in the year and will soon be found by general searching, some are densely pubescent and brightly coloured and these are more generally active by day; when the weather is warm they may be seen in flight or crawling over dung or carrion etc, they tend to move rapidly and can be very difficult to follow as the pattern of pubescence can break-up their outline when moving, they can also vanish instantly into cracks in the soil or among the host material. Pitfall trapping is generally a good way of sampling them, especially where the vegetation is lush and dense e.g. on wetland margins. None are saproxylic but specimens will regularly occur when turning logs or working old and loose bark, and during the warmer months at least some will be found climbing tree trunks or exploring old stumps in search of prey. Our fauna includes 24 species in 8 genera, the majority are widespread and many are locally common although because of their illusive behaviour at least some may be under-recorded. Among the most distinctive species are Emus hirtus (Linnaeus, 1758), Creophilus maxillosus (Linnaeus, 1758) and Ocypus olens. Species of Tasgius Stephens, 1829 and Ocypus Leach, 1819 are entirely black although some have pale legs and some are partly metallic, the genera are superficially similar and differ most obviously in the form of the mandibles, those of Ocypus have at least one large internal tooth while those of Tasgius are smooth, or almost so. The remaining genera include distinctly coloured or patterned species. Dinothenarus pubescens (De Geer, 1774), while lacking the bright colouration of many, is striking due to its golden-brown pubescence, it occurs throughout most of mainland UK but is generally very local and uncommon, it is typical of the group in being associated with dung, carrion and decaying fungi. Out two species of Ontholestes Ganglbauer, 1895 are also striking due to the pubescence, here it variegated in pale and dark hues of grey and cream across the body, giving the beetle a very cryptic appearance which must be seen in the living insect to appreciate. Both are widespread and locally common in the south. Staphylinus Linnaeus, 1758 and Platydracus Thomson, C.G., 1858 each include three strikingly-coloured UK species, they are readily separated by the form of the temples; rounded in the former and parallel-sided in the latter, specific identification relies on colour and is straightforward, even in the field. They are diurnal predators most likely to be found in open and sunny situations. Staphylinus erythropterus Linnaeus, 1758 and all our species of Platydracus are widespread though of local and sporadic occurrence while S. caesareus Cederhjelm, 1798 and S. dimidiaticornis Gemminger, 1851 are much more local and generally confined to the south and southwest.