Nomius pygmaeus, photographed by Harvey Schmidt.

Belongs within: Carabidae.
Contains: Trechodini, Tasmanorites, Geocharis, Patrobini, Scaritinae, Trechinae, Brachininae, Harpalinae, Amblytelus, Mecyclothorax, Broscinae, Elaphrinae.

The Conjunctae are a major clade of carabid ground beetles distinguished primarily by the presence of conjunct mesocoxae, with the coxal cavities surrounded by the mesosternum and metasternum. Members of this clade include the large subfamilies Harpalinae and Trechinae, though monophyly of the latter is uncertain.

Other subgroups of the Conjunctae include the Psydrini which have antennae with outer segments that are oval, constricted basally and less than 1.5 times as long as wide, as well as having deep transverse groves on abdominal sterna III and IV parallel to the posterior margin (Bell 1990). Nomius species have the basal two antennal segments glabrous and lack setigerous punctures on the elytral disc (Ball & Bousquet 2001). The Omophroninae have an oval body with the scutellum concealed dorsally, and the procoxal cavities closed with a projection of the prosternum inserted into a cavity in the proepimeron (Ball & Bousquet 2001). The Eurasian and North American genus Loricera has lateral antennal insertions and long, projected setae on antennomeres 2 to 6 (Ball & Bousquet 2001).

Meonis is a genus of ground beetles found in Australia with elongate, porrect mandibles that may feed on snails. Melisodera, found in southeastern Australia, has moniliform antennae, globular and strongly protruding eyes, and a laterally bisetose prothorax with a distinct submarginal ridge. Perileptus is an Old World genus of mostly minute ground beetles that are typically depigmented and densely pubescent, with pubescent eyes.

The diversity of ground beetles
Published 24 November 2008
Mating pair of the ground beetle Leptoferonia hatchi (Harpalinae, Pterostichini). Photo by Kipling Will.

It is well-known that beetles are one of the most diverse groups of animals in existence, and include more described species than any other “order” of organisms (though as we make further inroads into the remaining reservoir of undescribed species, I fully expect mites and Hymenoptera to give beetles a good run for their money). Within the beetles, one of the largest and best-known families, with over 30,000 described species*, are the ground beetles of the Carabidae. By way of comparison, this is a similar number of species to the entire collection of terrestrial vertebrates.

*Tree of Life says 30,000; Wikipedia says 40,000. In the absence of any other authority, I’ll go with Tree of Life.

Carabids have been one of the best-studied group of beetles because they are relatively large, often very colourful, and some species (notably the tiger beetles of the Cicindelinae) are often highly visible. Carabids are mostly active predators, generally feeding on any small invertebrate unfortunate enough to cross their path. The phylogeny of carabids is poorly resolved (Beutel et al. 2008), but one large clade that is generally recognised on morphological grounds (if not necessarily on molecular grounds—Maddison et al. 1999) is the Carabidae Conjunctae which, because I’ve got a thing against taxon names with more than one word in them, I’m just going to call Conjunctae from here on in*. The Conjunctae include three subfamilies (in the broad sense) of carabids, the Broscinae, Harpalinae and Psydrinae (Roig-Juñent & Cicchino 2001), though Roig-Juñent & Cicchino (2001) indicated that “Psydrinae” was para/polyphyletic with regard to the other two subfamilies, and other sources such as the Carabidae of the World database divide each group among a number of smaller subfamilies. Conjunctae are united by (and get their name from) their conjunct mesocoxae—the plates of the sternum (the underside of the thorax) are expanded to enclose the mesocoxae (the basalmost segments of the second pair of legs). Roig-Juñent & Cicchino (2001) identified a few other features that might unite the Conjunctae, such as the presence of an elytral plica (a distinct indentation at the back end of the elytra), but as those authors didn’t include a great many non-Conjunctae carabids in their analysis I’m not sure how certain those features are to be apomorphic.

*I think I can argue that this is fairly standard taxonomic practice. Quite a lot of taxon names are technically plural adjectives used as singular nouns. Plant family names, for instance, are explicitly required to be.

Mormolyce phyllodes, a somewhat different-looking ground beetle (Harpalinae, Lebiini) from South Asia. Photo by Sarefo.

The Conjunctae are one of the largest clades of carabids, but that is primarily due to the inclusion of the Harpalinae, which alone account for more than half of carabid species. Many Conjunctae (particularly many Harpalinae sensu lato) produce noxious defensive secretions when threatened, and members of the harpaline or near-harpaline tribe Brachinini are the infamous bombadier beetles, which are able to mix their defensive secretions to form an explosive mixture. The Harpalinae also include the Harpalini, which are unusual in having abandoned the carnivorous habits of their ancestors and turned to a life of seed-eating.

And just as an example of some of the unexpected things that sometimes turn up when I search online for stuff to use in these posts—it appears that Rita Skeeter might have belonged to the Conjunctae.

Systematics of Conjunctae

Synapomorphies (from Roig-Juñent & Cicchino 2001): Mesepimeron excluded from mesocoxal cavity; metepimeron forming shelf overlapping abdominal sternum II; elytral plica present; parascutellar striole absent; subapical setose organ present on gonopod; stylomere 1 or gonopod IX dimerous.

Conjunctae [Balteifera, Stylifera, Psydrinae, Psydritae, Trechitae]
| `--+--TrechinaeVB21
| `--+--+--BrachininaeVB21
| | `--HarpalinaeVB21
| `--+--+--Melisodera Westwood 1835OM08, LM87 [MelisoderiniR-JC01]
| | | `--*M. picipennis Westwood 1835LM87
| | `--+--AmblytelusOM08
| | `--MecyclothoraxOM08
| `--Meonis Castelnau 1867OM08, LM87 [MeonidiniR-JC01]
| |--*M. niger Castelnau 1867LM87
| |--M. angusticollis Sloane 1911LM87
| |--M. ater Castelnau 1867 [incl. M. amplicollis Sloane 1915]LM87
| |--M. convexus Sloane 1900LM87
| `--M. semistriatus Sloane 1916 [incl. M. minor Sloane 1916]LM87
| |--Psydrini [Nomiini]R-JC01
| | |--Nomius Castelnau 1835OM08, BB01 [incl. Haplochile LeConte 1848BB01]
| | | `--N. pygmaeus (Dejean 1831)B14
| | `--+--Laccocenus Sloane 1890OM08, LM87
| | | `--*L. ambiguus Sloane 1890LM87
| | `--Psydrus LeConte 1846OM08, BB01 [incl. Monillipatrobus Hatch 1933BB01]
| | `--P. piceus LeConte 1846BB01
| `--ElaphrinaeVB21
`--+--Loricera Latreille 1802L02 [LoricerinaeVB21, Loricerini]
| |--L. (Loricera)BB01
| | |--*L. (L.) pilicornis (Fabricius 1775)L02, VPB11 [=Carabus pilicornisL02]
| | |--L. (L.) aenea [=Pogonophorus (L.) aeneus]G20
| | |--L. (L.) decempunctata Eschscholtz 1829BB01
| | `--L. (L.) foveata LeConte 1851BB01
| |--L. (Elliptosoma Wollaston 1854)BB01
| `--L. (Plesioloricera Sciaky & Facchini 1999)BB01
`--Omophroninae [Omophronini]VB21
|--Phrator vittulatusB55
`--Omophron Latreille 1802 (see below for synonymy)BB01
|--O. congoenseB55
|--O. limbatumG20 [=Pogonophorus (Omophron) limbatusG20, Scolytus limbatusL20]
`--O. tesselatum Say 1823B14

Conjunctae incertae sedis:
Neonomius Moore 1963LM87
|--*N. laevicollis (Sloane 1915) [=Mecyclothorax laevicollis]LM87
|--N. australis (Sloane 1915) [=Mecyclothorax australis]LM87
`--N. laticollis (Sloane 1900) [=Cyclothorax laticollis]LM87
Sitaphe Moore 1963LM87
`--*S. rotundata Moore 1963LM87
Theprisa Moore 1963LM87
|--*T. convexa (Sloane 1920) [=Phersita convexa]LM87
|--T. australis (Castelnau 1867) [=Drimostoma australis]LM87
`--T. montana (Castelnau 1867) [=Drimostoma montana; incl. D. alpestris Castelnau 1867]LM87
Pterogmus Sloane 1920LM87
`--*P. rufipes Sloane 1920LM87
Teraphis Castelnau 1867 [=Phersita Sloane 1903]LM87
|--*T. melbournensis Castelnau 1867 [=*Phersita melbournensis; incl. T. argutoroides Castelnau 1867]LM87
|--T. cavicola Moore 1977LM87
|--T. crenulata (Sloane 1923) [=Phersita crenulata]LM87
|--T. elongata Castelnau 1867LM87
|--T. helmsi (Sloane 1890) [=Drimostoma helmsi]LM87
`--T. tasmanica (Sloane 1920) [=Phersita tasmanica]LM87
Trephisa Moore 1963LM87
`--*T. parallela Moore 1963LM87
Raphetis Moore 1963LM87
|--*R. darlingtoni Moore 1963LM87
`--R. gracilis Moore 1963LM87
Celanida Castelnau 1867 [=Celandia (l. c.)]LM87
`--*C. montana Castelnau 1867LM87
Rhaebolestes Sloane 1903LM87
`--*R. walkeri Sloane 1903LM87
Moriomorpha Castelnau 1867LM87
|--*M. victoriae Castelnau 1867LM87
`--M. adelaidae Castelnau 1867LM87
Moriodema Castelnau 1867LM87
`--*M. mcoyei Castelnau 1867 [incl. M. paramattensis Castelnau 1867]LM87
Epelyx Blackburn 1892LM87
|--*E. lindensis Blackburn 1892LM87
`--E. latus Blackburn 1892LM87
Tropopterus [Tropopterini]R-JC01
|--T. giuraudyiR-JC01
`--T. montagniiR-JC01
Percodermus Sloane 1920LM87
`--*P. niger Sloane 1920LM87
Paratrechodes Jeannel 1926LM87
`--*P. macleayi (Sloane 1920) [=Trechus macleayi]LM87
Trechobembix Jeannel 1926LM87
`--*T. baldiensis (Blackburn 1894) [=Trechus baldiensis]LM87
|--T. b. baldiensisLM87
|--T. b. hesperia Moore 1972LM87
`--T. b. queenslandica Moore 1972LM87
Cyphotrechodes Jeannel 1926LM87
`--*C. gibbipennis (Blackburn 1901) [=Trechodes gibbipennis]LM87
Perileptus Schaum 1860B09 [PerileptiniB74]
| i. s.: P. africanusB55
| P. morimotoi Uéno 1955I92
| P. sloanei Moore 1966LM87
| P. westralis Moore 1972LM87
|--*P. (Perileptus) areolatus (Creutzer 1799) [=Carabus areolatus]LM87
`--P. (Pyrrhotachys Sloane 1896)B09 [=PyrrotachysLM87]
|--P. (*P.) constrictipes (Sloane 1896) [=*Pyrrotachys constrictipes]LM87
`--P. (P.) constricticeps (Sloane 1903)LB91, LM87 [=Pyrrotachys constricticepsLM87]
|--Pogonoschema Jeannel 1927B70, LM87
| |--*P. robustum (Sloane 1920) [=Trechus robustus]LM87
| |--P. pallipes Moore 1972LM87
| |--P. sloanei Jeannel 1927 [=Trechus pacificus Sloane 1920 non Putzeys 1870]LM87
| `--P. solidum Moore 1972LM87
`--Sloanella Jeannel 1927B70, LM87
|--*S. simsoni (Blackburn 1894) [=Trechus simsoni]LM87
|--S. obscura Moore 1893LM87
|--S. pallida Moore 1972LM87
`--S. suavis Moore 1972LM87
Tropidotrechus Jeannel 1927LM87
|--*T. victoriae (Blackburn 1894) [=Trechus victoriae]LM87
|--T. bawbawensis Moore 1972LM87
|--T. microps Moore 1972LM87
`--T. vicinus Moore 1972LM87
Austrotrechus Moore 1972LM87
|--*A. kosciuskoanus (Sloane 1923) [=Trechus kosciuskoanus]LM87
`--A. contortus Moore 1972LM87
Tasmanotrechus Moore 1972LM87
|--*T. leai (Sloane 1920) [=Trechus leai]LM87
|--T. cockerilli Moore 1972LM87
|--T. compactus Moore 1983LM87
`--T. concolor Moore 1972LM87
Geodetrechus Moore 1972LM87
|--*G. talpinus Moore 1972LM87
|--G. mendumae Moore 1972LM87
`--G. parallelus Moore 1972LM87
Nototrechus Moore 1972LM87
`--*N. unicolor Moore 1972LM87
Trechistus Moore 1972LM87
|--*T. humicola Moore 1972LM87
|--T. inconspicuus Moore 1972LM87
|--T. stenoderus Moore 1972LM87
|--T. sylvaticus Moore 1972LM87
`--T. terricola Moore 1972LM87
Trechiella Jeannel 1927LM87
|--*T. subornatella (Blackburn 1901) [=Trechus subornatellus]LM87
`--T. queenslandica Moore 1972LM87
Mimanillus Moore 1972LM87
`--*M. gracilis Moore 1972LM87
Eutrechopsis Moore 1972LM87
`--*E. ovalis Moore 1972LM87
Mimotrechus Moore 1972LM87
|--*M. australiensis (Sloane 1923) [=Trechus australiensis]LM87
|--M. carteri (Sloane 1920) [=Trechus carteri]LM87
|--M. obscuroguttatus Moore 1972LM87
`--M. scitulus Moore 1972LM87
Bothynotrechus Moore 1972LM87
|--*B. castelnaui (Sloane 1920) [=Trechus castelnaui]LM87
`--B. lynx Moore 1972LM87

Omophron Latreille 1802 [=Homophron Semenov 1922; incl. Istor Semenov 1922, Paromophron Semenov 1922, Prosecon Semenov 1922]BB01

*Type species of generic name indicated


[B09] Baehr, M. 2009. A new species of the tachyine genus Tasmanitachoides from the Kimberley Division, Western Australia (Coleoptera, Carabidae). Records of the Western Australian Museum 25 (2): 159–164.

[BB01] Ball, G. E., & Y. Bousquet. 2001. Carabidae Latreille, 1810. In: Arnett, R. H., Jr & M. C. Thomas (eds) American Beetles vol. 1. Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia pp. 32–132. CRC Press: Boca Raton.

[B55] Basilewsky, P. 1955. Carabidae (Coleoptera) de l’Angola (première partie). Diamang Publicações Culturais 27: 91–137.

Beutel, R. G., I. Ribera & O. R. P. Bininda-Emonds. 2008. A genus-level supertree of Adephaga (Coleoptera). Organisms Diversity & Evolution 7 (4): 255–269.

[B14] Bouchard, P. (ed.) 2014. The Book of Beetles: A lifesize guide to six hundred of nature’s gems. Ivy Press: Lewes (United Kingdom).

[B70] Britton, E. B. 1970. Coleoptera (beetles). In: CSIRO. The Insects of Australia: A textbook for students and research workers pp. 495–621. Melbourne University Press.

[B74] Britton, E. B. 1974. Coleoptera (beetles). In: CSIRO. The Insects of Australia: A textbook for students and research workers. Supplement 1974 pp. 62–89. Melbourne University Press.

[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.

[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.

[L02] Latreille, P. A. 1802. Histoire Naturelle, générale et particulière des crustacés et des insectes vol. 3. Familles naturelles des genres. F. Dufart: Paris.

[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).

[LM87] Lawrence, J. F., B. P. Moore, J. E. Pyke & T. A. Weir. 1987. Zoological Catalogue of Australia vol. 4. Coleoptera: Archostemata, Myxophaga and Adephaga. Australian Government Publishing Service: Canberra.

Maddison, D. R., M. D. Baker & K. A. Ober. 1999. Phylogeny of carabid beetles as inferred from 18S ribosomal DNA (Coleoptera: Carabidae). Systematic Entomology 24: 103–138.

[OM08] Ober, K. A., & D. R. Maddison. 2008. Phylogenetic relationships of tribes within Harpalinae (Coleoptera: Carabidae) as inferred from 28S ribosomal DNA and the wingless gene. Journal of Insect Science 8: 63.

[R-JC01] Roig-Juñent, S., & A. C. Cicchino. 2001. Chaltenia patagonica, new genus and species belonging to Chalteniina, a new subtribe of Zolini (Coleoptera: Carabidae). Canadian Entomologist 133: 651–670.

[VPB11] Varet, M., J. Pétillon & F. Burel. 2011. Comparative responses of spider and carabid beetle assemblages along an urban-rural boundary gradient. Journal of Arachnology 39 (2): 236–243.

[VB21] Vasilikopoulos, A., M. Balke, S. Kukowka, J. M. Pflug, S. Martin, K. Meusemann, L. Hendrich, C. Mayer, D. R. Maddison, O. Niehuis, R. G. Beutel & B. Misof. 2021. Phylogenomic analyses clarify the pattern of evolution of Adephaga (Coleoptera) and highlight phylogenetic artefacts due to model misspecification and excessive data trimming. Systematic Entomology 46: 991–1018.

[Z05] Zaballos, J. P. 2005. Los Geocharis Ehlers, 1883 de Marruecos y Cádiz (España) (Coleoptera, Carabidae, Trechinae, Anillini). Graellsia 61 (1): 61–81.

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