Belongs within: Staphylinoidea.
Contains: Camiarinae, Leiodinae, Cholevini, Dissochaetus, Leptodirini, Ptomaphagini.
The Leiodidae are mostly scavenging or fungivorous beetles, often found in decaying organic matter; a number of species are known from caves. They are diverse in body form but can mostly be recognised by the form of the eighth antennal segment, which is smaller than the seventh and ninth segments on either side of it.
Members of the subfamily Cholevinae are characterised by a sharp occipital crest that rests against the front of the pronotum when the head is in repose. Males of the genus Nemadus have expanded protarsi and weakly dilated mesotarsomeres that are spongy pubescent beneath. The eastern North American Prionochaeta opaca has long, serrate tibial spurs with the longest spur on the hind leg as long as the first tarsomere (Peck 2001). The Oritocatopini of sub-Saharan Africa have a weak occipital carina and a very long apical segment on the maxillary palpi.
Characters (Lawrence & Britton 1991): Moderately small beetles with more or less spiny legs and usually simple tarsi, abdomen usually entirely concealed by elytra. Antennae eleven-segmented, usually with five-segmented antennal club, second segment of club (antennal segment 8) smaller than either first or third, club sometimes very weak with antennal segment 8 only slightly reduced, or very strong with 8 greatly reduced or absent, unique internal sensory vesicles usually opening on distal surfaces of segments 7, 9 and 10. Larvae active, campodeiform, urogomphi almost always articulated at base; mandibular mola and two apical maxillary lobes (galea and lacinia) present.
Leiodidae [Anisotomidae, Camiaridae, Sogdiidae]
| i. s.: CatopidiusGE05
| GelaeB14
| RagytodesLB91
| CumianitesGN09
| Nyujwa zherichini Perkovsky 1990RJ93
|--+--CamiarinaeLC20
| `--+--Afrocatops [Oritocatopini]LC20
| `--LeiodinaeLC20
`--Cholevinae [Anemadini, Catopidae, Catopinae, Cholevidae]LC20
| i. s.: Micronemadus pusillimus (Kraatz 1877) [=Nemadus pusillimus]SP76
| CholevinusSP76
| DzungaritesSP76
| CryocatopsSP76
| PtomaphaginusSP76
| |--P. oribatesSP76
| `--P. palpalis Szymczakowski 1974SP76
| CatopodesSP76
| |--C. calceatus Szymczakowski & Plath 1976SP76
| `--C. fuscifronsSP76
| MesocatopsSP76
| |--M. imitatorSP76
| |--M. latitarsisSP76
| `--M. retroflexus Szymczakowski & Plath 1976SP76
| Pseudonemadus australisLB91
| AustronemadusLB91
| CatoposchemaLB91
| NargiotesLB91
| Eucatops [Eucatopini]S05
| |--E. (Eucatops)S05
| | |--E. (E.) incognitus Salgado 2003S05
| | `--E. (E.) obtusus Gnaspini 1994S05
| |--E. (Napocatops) giganteusS05
| `--E. (Sphaerocatops) granuliformis Salgado 2003S05
|--+--Speonemadus angusticollisLC20
| `--CholeviniLC20
`--+--+--DissochaetusLC20
| `--Nargomorphus amplicollisMF15
`--+--+--Paracatops brunneipesLC20, E02
| `--Prionochaeta Horn 1880LC20, P90
| `--P. opaca (Say 1825)P01
`--+--LeptodiriniLC20
`--+--PtomaphaginiLC20
`--Nemadus Thomson 1867LC20, P01 (see below for synonymy)
|--N. colonoidesP92
`--N. microtomographicusLC20
Nemadus Thomson 1867LC20, P01 [incl. Eonargus Iablokoff-Khnzorian 1959P01, Laferius Perkovsky 1994P01; Nemadini]
*Type species of generic name indicated
References
[B14] Bouchard, P. (ed.) 2014. The Book of Beetles: A lifesize guide to six hundred of nature’s gems. Ivy Press: Lewes (United Kingdom).
[E02] Emberson, R. M. 2002. The beetle (Coleoptera) fauna of the Chatham Islands: additions and corrections. New Zealand Entomologist 25: 69–77.
[GN09] Grebennikov, V. V., & A. F. Newton. 2009. Good-bye Scydmaenidae, or why the ant-like stone beetles should become megadiverse Staphylinidae sensu latissimo (Coleoptera). European Journal of Entomology 106: 275–301.
[GE05] Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press: New York.
[LB91] Lawrence, J. F., & E. B. Britton. 1991. Coleoptera (beetles). In: CSIRO. The Insects of Australia: A textbook for students and research workers 2nd ed. vol. 2 pp. 543–683. Melbourne University Press: Carlton (Victoria).
[LC20] Lü, L., C.-Y. Cai, X. Zhang, A. F. Newton, M. K. Thayer & H.-Z. Zhou. 2020. Linking evolutionary mode to palaeoclimate change reveals rapid radiations of staphylinoid beetles in low-energy conditions. Current Zoology 66 (4): 435–444.
[MF15] McKenna, D. D., B. D. Farrell, M. S. Caterino, C. W. Farnum, D. C. Hawks, D. R. Maddison, A. E. Seago, A. E. Z. Short, A. F. Newton & M. K. Thayer. 2015. Phylogeny and evolution of Staphyliniformia and Scarabaeiformia: forest litter as a stepping stone for diversification of nonphytophagous beetles. Systematic Entomology 40: 35–60.
[P90] Peck, S. B. 1990. Insecta: Coleoptera Silphidae and the associated families Agyrtidae and Leiodidae. In: Dindal, D. L. (ed.) Soil Biology Guide pp. 1113–1136. John Wiley & Sones: New York.
[P01] Peck, S. B. 2001. Leiodidae Fleming, 1821. In: Arnett, R. H., Jr & M. C. Thomas (eds) American Beetles vol. 1. Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia pp. 250–258. CRC Press: Boca Raton.
[P92] Poinar, G. O., Jr. 1992. Life in Amber. Stanford University Press: Stanford.
[RJ93] Ross, A. J., & E. A. Jarzembowski. 1993. Arthropoda (Hexapoda; Insecta). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 363–426. Chapman & Hall: London.
[S05] Salgado, J. M. 2005. Cholevinae (Coleoptera, Leiodidae) from Ecuador: new data and two new species. Graellsia 61 (1): 51–60.
[SP76] Szymczakowski, W., & D. Plath. 1976. Catopidae aus dem Nepal-Himalaya (Ins., Col.) Senckenbergiana Biologica 57 (1-3): 35–48.