RAYMONDIONYMINI Reitter, 1913
This unusual subterranean weevil is very elusive and difficult to find; specialized trapping techniques will most likely be needed to observe it.
Around the World
Historically the higher order classification of this group has been rather turbulent; it has formerly been included either as a distinct family within the Curculionoidea or as a subfamily of the Curculionidae; there is no doubt of its distinct lineage and neither of its affinity with the Erirhininae-itself sometimes classified as a distinct family-and it has also variously been included as a subgroup of that group but the most modern system includes both groups as distinct tribes of the Brachycerinae Billberg, 1820. The group is included as a family in the latest UK checklist (2018), but we have followed the most recent Palaearctic checklist, wherein it is listed as a tribe of the Brachycerinae. This small tribe includes about 90 species of subterranean weevils in 16 genera and, variously, is divided into two subfamilies although this is likely to change as exotic groups may be removed in the future. The Myrtonyminae Kuschel, 1990 includes 6 species of the single genus Myrtonymus Kuschel, 1990 which occur in Australia and New Zealand. The remainder are included in the Raymondionyminae Reitter, 1913 which, with the exception of two genera, all occur in the northern hemisphere. Homosomus Richard, 1956 includes three species and is endemic to Madagascar while Bordoniola Osella, 1987 includes seven Neotropical species; two from Argentina and five from Ecuador. Three genera occur in the United States; Gilbertiola Osella, 1982 includes two species, the monotypic Schizomicrus Casey, 1905 is endemic to California, and Alaocybites Gilbert, 1956 includes two species as well as another from eastern Russia. The monotypic Neoubychia Gilbert & Howden, 1987 occurs in at least three locations in the Mexican cloud forests. The Madagascan genus Homosomus, sometimes included in a distinct tribe, is only poorly defined and may belong elsewhere; it may simply be similarly adapted for a subterranean way of life. The remainder are Palaearctic and of these the majority occur around the Mediterranean; Alaocyba Perris, 1869 includes 10 species with several endemic to North Africa while the following are native to Mediterranean areas: Alaocephala Ganglbauer, 1906 (3 species), Derosasius Ganglbauer, 1906, which includes 3 Mediterranean endemics, Coiffaitiella Osella, 1977 (7 species), Raymondiellus Ganglbauer, 1906 (17 species including several from North Africa), Raymondionymus Wollaston, 1873 (29 species restricted to Europe), Tarattostichus Ganglbauer, 1906 (2 species) and Ferreria Alonso-Zarazaga & Lyal, 1999 includes 2 species, of which F. marqueti (Aubé, 1863) occurs as 4 distinct subspecies, the nominate subspecies extending to the UK while Ubychia Rost, 1893 includes 11 species from Europe as well as further east.
All species are entirely testaceous to dark brown, often with the head, pronotum and legs darker, and the cuticle often has a translucent appearance They have a characteristic elongate-oval form with rounded pronotum and elytra and a broad head which is retracted into the prothorax, a long and curved rostrum and generally strongly punctured dorsal surface including distinctly punctured elytral striae. The antennae are inserted towards the end of the rostrum in scrobes that run latero-ventrally so the insertions are not visible from above; they are long with a curved and distally thickened scape, 6-segmented funiculus (5- or 7-segmented in some exotic groups) and a 4-segmented club. They usually lack eyes although in Neoubychia and Alaocybites egorovi Grebennikov, 2010 there are single ommatidia. The pronotum is convex and rounded, generally elongate, lacking sculpture and strongly punctured, the prosternum is usually broadly depressed anterior to the coxae which may be separated or contiguous. The mesocoxae are separated. The legs are robust and moderately long with thickened femora and flat, dilated tibiae which are often angled either externally or internally and have a comb of stiff setae around the angle and a small tooth on the external or internal apical angle. The tarsi are 4-segmented and generally without bilobed segments, in Raymondionymus segment 3 is expanded into a vertical spine and segment 4 is prolonged apically over the claws. In most species the dorsal surface has very sparse, short and pale pubescence.
The biology of the family is poorly known; they live in the soil, sometimes at considerable depth, among dead or decaying plant roots upon which they are thought to feed. Some foreign groups live among deep leaf-litter and some occasionally occur under logs and debris in contact with the soil.
Ferreria marqueti (Aubé, 1863)
This is the only member of the family recorded from the U.K. It was first reported from South London (Kew Gardens, Surrey) in 1964 and has since been found at several sites in the southeast; Surrey, Kent, Middlesex and Dorset, it is usually found deep in the soil by using deep subterranean pitfall traps but has also been found among excavated dead conifer roots and under surface litter on disturbed soil in gardens etc., and it generally occurs in numbers when found. Adults have been recorded throughout the year. The species natural range is southern and central European extending into Switzerland, Tunisia and Corsica, and so it is thought that U.K. populations may have been introduced with imported horticultural material. Four subspecies are known on the continent and the U.K. specimens belong to the nominotypical subspecies.
Ferreria is unmistakable among the U.K. fauna, it is small, 1.9-3.1mm, entirely testaceous to dark brown, with short pale pubescence and a very distinctive appearance, elongate-oval with a long, cylindrical and curved rostrum which is slightly shorter than the pronotum, the is head mostly retracted into the elongate, rounded and strongly punctured prothorax, and the antennae are long with a clubbed scape, 6-segmented funiculus and abrupt 4-segmented club. The elytra are elongate with distinct shoulders and continuously curved apices; each elytron has 6 well-defined rows of very strong and deep punctures and is explanate behind the middle. The legs are flattened with long and thickened femora and short tibiae which are expanded towards the apex and toothed on the inner apical angle. The tarsi are 4-segmented with the terminal segment the longest. The claws are well-developed, free at the base and smooth. The male abdomen is widely and deeply impressed, the female smooth or only very weakly depressed.