Belongs within: Dytiscinae.
The Aciliini are a clade of diving beetles, distinguished by the possession of bifid metatibial spurs, and extremely long gonocoxae with expanded and rounded apices and apicolateral margins concave (Miller 2003). Members of the Aciliini lay their eggs in cracks in wood, moss or other cryptic locations (Miller 2001). Within the Aciliini, members of the Holarctic genus Acilius are characterised by large, dense punctation over much of the body surface in contrast to the finer, sparser punctation found in other genera. The genus Thermonectus includes two species, T. marmoratus and T. zimmermanni, that are strikingly patterned with bright yellow markings (Bouchard 2014).
<==Aciliini [Thermonectini] |--Thermonectus Dejean 1833M03, RL01 [=ThermonetusBM06] | | i. s.: T. ornaticollisM01 | | T. zimmermaniB14 | |--+--T. variegatusBMB14 | | `--+--T. alfrediBMB14 | | `--T. marmoratus Hope 1832BMB14, B14 | `--+--+--T. circumscriptus Latr. 1809BMB14, FS90 (see below for synonymy) | | `--T. leprieuriBMB14 | `--+--T. nigrofasciatusBMB14 | `--+--T. succinctusBMB14 | `--+--+--T. basilaris Harris 1829BMB14, FS90 (see below for synonymy) | | `--T. intermediusBMB14 | `--+--T. margineguttatus Aubé 1838BMB14, FS90 | `--T. nobilisBMB14 `--+--+--Tikoloshanes Omer-Cooper 1956BMB14 | | `--T. eretiformis Omer-Cooper 1956BMB14 | `--Aethionectes Sharp 1882BMB14 | |--A. apicalisM01 | |--A. oberthueriBMB14 | `--A. optatusM01 `--+--+--Rhantaticus Sharp 1882BMB14, LM87 | | `--R. congestus (Klug 1833) (see below for synonymy)LM87 | `--Sandracottus Sharp 1882BMB14, LM87 | | i. s.: *S. mixtus (Blanchard 1853) [=Acilius mixtus]LM87 | |--S. dejeaniiBMB14 | `--+--S. fasciatusBMB14 | `--+--S. bakewelli (Clark 1864)BMB14, LM87 [=Hydaticus bakewelliLM87; incl. S. guttatus Sharp 1882LM87] | `--+--S. gueriniBMB14 | `--S. insignisBMB14 `--+--Graphoderus Dejean 1833M03, RL01 (see below for synonymy) | |--G. liberusM03 | `--+--G. fascicollisM03 | `--+--G. perplexusBMB14 | `--+--+--G. bilineatusBMB14 | | `--+--G. austriacusBMB14 | | `--G. occidentalisBMB14 | `--+--+--G. adamsiiBMB14 | | `--G. bieneriBMB14 | `--+--G. cinereus (Linnaeus 1758)BMB14, NR97 [=Dytiscus cinereusNR97, *Prosciastes cinereusNR97] | `--G. zonatusBMB14 `--Acilius Leach 1817 (nom. cons.)M03, RL01 [=Heteroelytrus Ádám 1993BM06; incl. Homoeolytrus Gobert 1874BM06] | i. s.: A. florissantensis Wickham 1909BMB14 | A. oeningensis (Heer 1847) [=Dytiscus oeningensis]BM06 | A. praesulcatus Łomnicki 1894BM06 | A. sinensis Peschet 1915BM06 |--+--+--A. canaliculatus (Nicolai 1822)BMB14, BM06 (see below for synonymy) | | `--A. duvergeri Gobert 1874BMB14, BM06 [=A. (*Homoeolytrus) duvergeriBM06] | `--+--*A. sulcatus (Linnaeus 1758)BM06, BMB14, NR97 (see below for synonymy) | `--+--A. japonicus Brinck 1939BMB14, BM06 | `--A. kishii Nakane 1963BMB14, I92 [=A. japonicus kishiiBM06] `--+--A. athabascae Larson 1975BMB14, BM06 `--+--+--A. fraternus (Harrsi 1828)BMB14, BM06 (see below for synonymy) | `--A. mediatus (Say 1823)BMB14, BM06 (see below for synonymy) `--+--+--A. abbreviatus Aubé 1838BMB14, BM06 (see below for synonymy) | `--A. semisulcatus Aubé 1838BMB14 `--+--A. confusus Bergsten & Miller 2006BMB14, BM06 `--A. sylvanus Hilsenhoff 1975BMB14, BM06
Acilius abbreviatus Aubé 1838BMB14, BM06 [=A. semisulcatus var. abbreviatusBM06; incl. A. latiusculus LeConte 1857BM06, A. semisulcatus latiusculusBM06, A. semisulcatus var. oregonensis Crotch 1873BM06, A. simplex LeConte 1852BM06, A. semisulcatus var. simplexBM06]
Acilius canaliculatus (Nicolai 1822)BMB14, BM06 [=Dytiscus canaliculatusBM06, Heteroelytrus canaliculatusBM06, Hydaticus canaliculatusBM06, Dytiscus sulcipennis Sahlberg 1824BM06; incl. Acilius caliginosus Curtis 1825BM06, A. dispar Lacordaire 1835BM06, A. kotulae von Ulanowsky 1884BM06, A. laevisulcatus de Motschulsky 1845BM06, A. subimpressus de Motschulsky 1845BM06, Dytiscus sulcatus var. sulcatoaffinis Hummel 1822BM06, A. canaliculatus var. xantischius des Gozis 1911BM06]
Acilius fraternus (Harrsi 1828)BMB14, BM06 [=Dytiscus fraternusBM06; incl. A. fraternus dismalus Matta & Michael 1976BM06]
Acilius mediatus (Say 1823)BMB14, BM06 [=Dytiscus mediatusBM06, A. (Homoeolytrus) mediatusBM06, A. (Homoeodytes [l.c.]) mediatusM01, Thermonectus mediatusBM06; incl. Colymbetes (Hydaticus) maccullochii Kirby 1837BM06]
*Acilius sulcatus (Linnaeus 1758)BM06, BMB14, NR97 [=Dytiscus sulcatusNR97, *Heteroelytrus sulcatusNR97, Hydaticus sulcatusBM06; incl. Acilius sulcatus blancki de Peyerimhoff 1927BM06, A. brevis Aubé 1837BM06, A. sulcatus brevisBM06, Dytiscus fasciatus De Geer 1774BM06, A. fasciatusBM06, D. punctatus Scopoli 1763BM06, D. scopolii Gmelin 1790BM06, Acilius sulcatus var. scoticus Stephens 1828BM06, A. tomentosus de Motschulsky 1845BM06, A. sulcatus var. varipes Stephens 1828BM06]
Graphoderus Dejean 1833M03, RL01 [incl. Derographus Portevin 1929RL01, Graphothorax Motschulsky 1853RL01, Prosciastes Gistel 1856RL01]
Rhantaticus congestus (Klug 1833) [=Hydaticus congestus; incl. H. signatipennis Castelnau 1834, *Rhantaticus signatipennis]LM87
Thermonectus basilaris Harris 1829BMB14, FS90 [incl. T. forstroemiFS90, T. incisusFS90, T. nimbatusFS90, T. sculpturatusFS90]
Thermonectus circumscriptus Latr. 1809BMB14, FS90 [incl. T. brasiliensisFS90, T. havaniensisFS90, T. insculptusFS90, T. insularisFS90, T. subfasciatusFS90]
*Type species of generic name indicated
References
[BM06] Bergsten, J., & K. B. Miller. 2006. Taxonomic revision of the Holarctic diving beetle genus Acilius Leach (Coleoptera: Dytiscidae). Systematic Entomology 31: 145–197.
[B14] Bouchard, P. (ed.) 2014. The Book of Beetles: A lifesize guide to six hundred of nature’s gems. Ivy Press: Lewes (United Kingdom).
[BMB14] Bukontaite, R., K. B. Miller & J. Bergsten. 2014. The utility of CAD in recovering Gondwanan vicariance events and the evolutionary history of Aciliini (Coleoptera: Dytiscidae). BMC Evolutionary Biology 14: 5.
[FS90] Fleutiaux, E., & A. Sallé. 1890. Liste des coléoptères de la Guadeloupe et descriptions d’espèces nouvelles. Annales de la Société Entomologique de France, 6e série 9: 351–484.
[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.
[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.
[M01] Miller, K. B. 2001. On the phylogeny of the Dytiscidae (Insecta: Coleoptera) with emphasis on the morphology of the female reproductive system. Insect Systematics and Evolution 32: 45–92.
[M03] Miller, K. B. 2003. The phylogeny of diving beetles (Coleoptera: Dytiscidae) and the evolution of sexual conflict. Biological Journal of the Linnaean Society 79: 359–388.
[NR97] Nilsson, A. N., & R. E. Roughley. 1997. The genus- and family-group names of the Dytiscidae—additions and corrections. Beiträge zur Entomologie 47 (2): 359–364.
[RL01] Roughley, R. E., & D. J. Larson. 2001. Dytiscidae Leach, 1815. In: Arnett, R. H., Jr & M. C. Thomas (eds) American Beetles vol. 1. Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia pp. 156–186. CRC Press: Boca Raton.