Belongs within: Medusozoa.
The Codonophora are a clade within the siphonophores characterised by the presence of nectosomes, bell-shaped zooids specialised for swimming, and gelatinous shield-like bracts; these latter are lost in some subgroups (Dunn et al. 2005). They have been divided between the Physonectae, with a small apical pneumatophore, and the Calycophorae, lacking a pneumatophore, but the former are probably paraphyletic to the latter (Daly et al. 2007).
<==Codonophora [Brachystelia, Physonectae]
| i. s.: Lychnagalma utricularia [incl. L. vesicularia]DPH05
| Discolabe quadrigataH04
| Strobalia cupolaH04
|--ApolemaDPH05 [ApolemidaeDB07]
`--+--Cordagalma cordiformeDPH05
|--ErennaDPH05
|--RhodaliidaeDPH05
| |--Stephalia dilataDPH05
| `--Dendrogramma Just, Kristensen & Olesen 2014 [Dendrogrammatidae]OH16, JKO14
| `--*D. enigmatica Just, Kristensen & Olesen 2014JKO14 [incl. D. discoides Just, Kristensen & Olesen 2014OH16, JKO14]
|--StephanomiaDPH05
| |--S. amphytridis [=Halistemma amphytridis, S. amphitridis (l. c.)]DPH05
| |--S. bijugaB26
| |--S. caraB26
| `--S. uvariaR26
|--PyrostephidaeDB07
| |--Pyrostephos vanhoeffeniPO99
| `--BargmanniaDPH05
| |--B. amoenaDPH05
| `--B. elongataDPH05
|--+--+--Physophora [Physophoridae]DPH05
| | | |--P. borealisM06
| | | |--P. hydrostaticaDPH05
| | | `--P. musonemaG20
| | `--Forskalia [Forskaliidae]DPH05
| | |--F. tholoidesDPH05
| | `--+--F. edwardsiDPH05
| | `--+--F. asymmetricaDPH05
| | `--F. formosaDPH05
| `--AgalmatidaeDPH05
| |--NanomiaDPH05
| | |--N. bijugaDPH05
| | `--N. caraIF02
| `--+--Halistemma rubrumDPH05
| `--AgalmaDPH05
| |--A. clausiDPH05
| `--+--A. elegansDPH05
| `--+--A. okeniDPH05
| `--Athorybia [Athorybiidae]DPH05
| `--A. rosaceaDPH05
`--Calycophorae [Calyconectae]DB07
|--+--Praya [Prayidae]DPH05
| | |--P. dubiaDPH05
| | `--P. galeaH04
| `--+--Nectadamas diomedeaeDPH05
| `--Nectopyramis natansDPH05
`--+--Craseoa latheticaDPH05
|--+--+--Gymnopraia lapislazulaDPH05
| | `--Rosacea flaccidaDPH05
| `--Vogtia Kölliker 1853DPH05
| |--V. pentacanthaDPH05
| `--+--V. glabraDPH05
| `--Hippopodius Quoy & Gaimard 1827 [Hippopodiidae]DPH05
| `--H. hippopusDPH05
`--+--+--Chuniphyes multidentataDPH05
| `--Clausophyes [Clausophyidae]DPH05
| `--C. ovataDPH05
`--+--Sphaeronectes [Sphaeronectidae]DPH05
| |--S. fragilisPO99
| |--S. gracilisDPH05
| `--S. irregularisPO99
`--DiphyidaeDPH05
|--+--Muggiaea atlanticaDPH05
| `--+--Lensia conoideaDPH05
| `--Sulculeolaria quadrivalvisDPH05
`--+--Chelophyes appendiculataDPH05
`--+--AbylidaeDPH05
| |--Abylopsis tetragonaDPH05
| `--Bassia obeliscusH04
`--DiphyesDPH05
|--D. appendiculataB26
|--D. arcticaB26
|--D. bojaniB26
|--D. chamissonisZS10
|--D. disparDPH05
|--D. spiralisB26
`--D. truncataB26
*Type species of generic name indicated
References
[B26] Bigelow, H. B. 1926. Plankton of the offshore waters of the Gulf of Maine. Bulletin of the Bureau of Fisheries 40 (2): 1–509.
[DB07] Daly, M., M. R. Brugler, P. Cartwright, A. G. Collins, M. N. Dawson, D. G. Fautin, S. C. France, C. S. McFadden, D. M. Opresko, E. Rodriguez, S. L. Romano & J. L. Stake. 2007. The phylum Cnidaria: a review of phylogenetic patterns and diversity 300 years after Linnaeus. Zootaxa 1668: 127–182.
[DPH05] Dunn, C. W., P. R. Pugh & S. H. D. Haddock. 2005. Molecular phylogenetics of the Siphonophora (Cnidaria), with implications for the evolution of functional specialization. Systematic Biology 54 (6): 916–935.
[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.
[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.
[IF02] Ivantsov, A. Yu., & M. A. Fedonkin. 2002. Conulariid-like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary. Palaeontology 45 (6): 1219–1229.
[JKO14] Just, J., R. M. Kristensen & J. Olesen. 2014. Dendrogramma, new genus, with two new non-bilaterian species from the marine bathyal of southeastern Australia (Animalia, Metazoa incertae sedis)—with similarities to some medusoids from the Precambrian Ediacara. PLoS One 9 (9): e102976.
[M06] Maas, O. 1906. Die arktischen Medusen (ausschliesslich der Polypomedusen). In: Römer, F., & F. Schaudinn (eds) Fauna Arctica. Eine Zusammenstellun der arktischen Tierformen, mit besonder Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898 vol. 4 pp. 479–526. Gustav Fischer: Jena.
[OH16] O’Hara, T. D., A. F. Hugall, H. MacIntosh, K. M. Naughton, A. Williams & A. Moussalli. 2016. Dendrogramma is a siphonophore. Current Biology 26: R457–R458.
[PO99] Pagès, F., & C. Orejas. 1999. Medusae, siphonophores and ctenophores of the Magellan region. Scientia Marina 63 (Suppl. 1): 51–57.
[R26] Risso, A. 1826. Histoire naturelle des principales productions de l’Europe méridionale et particulièrement de celles des environs de Nice et des Alpes maritimes vol. 5. F.-G. Levrault: Paris.
[ZS10] Zhang, G.-T., S. Sun, Z.-L. Xu & Q.-L. Zhang. 2010. Unexpected dominance of the subtropical copepod Temora turbinata in the temperate Changjiang River estuary and its possible causes. In: China-Russia Bilateral Symposium: Proceedings of the China-Russia Bilateral Symposium of “Comparison on Marine Biodiversity in the Northwest Pacific Ocean”, 10–11 October 2010, Qingdao (China) pp. 100–102. Institute of Oceanology, Chinese Academy of Sciences; A. V. Zhirmunsky Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences.