Halicreas minimum, from NOAA Office of Ocean Exploration and Research.
Belongs within: Medusozoa.

The Trachymedusae are a group of hydrozoans lacking a polyp stage to the life cycle. Medusae develop directly from an actinula (Petersen 1979).

<==Trachymedusae DB07
|  i. s.: Carmaris glitschi H04
|         Carmarina hastata H04
|         Aglantha B26
|           |–A. digitale C02
|           `–A. rosea B26
|         Pantachogon haeckeli LS09
|         Amphogona apicata PO99
|–Ptychogastria [Ptychogastriidae] BP00
|    `–P. asteroides (Haeckel 1879) BP00
|–Craspedacusta Lankester 1880 G88, P79 [Petasidae DB07]
|    `–C. sowerbyi G88
|–Rhopalonematidae DB07
|    |–Rhopalonema B26
|    |    |–R. funerarium B26
|    |    `–R. velatum B26
|    |–Homoeonema platygonon Browne 1903 BP00
|    `–Persa incolorata McCrady 1859 BP00
|–Geryoniidae DB07
|    |–Geryones elephas H04
|    `–Liriope DB07
|         |–L. scutigera B26
|         `–L. tetraphylla B26
`–Halicreatidae DB07
|–Varitentaculata DB07
`–Halicreas CH97
|–H. minimum CH97
`–H. papillosum B26

*Type species of generic name indicated


[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.

[BP00] Bouillon, J., F. Pagès, J.-M. Gili, A. Palanques, P. Puig & S. Heussner. 2000. Deep-water hydromedusae from the Lacaze-Duthiers submarine canyon (Banyuls, northwestern Mediterranean) and description of two new genera, Guillea and Parateclaia. Scientia Marina 64 (Suppl. 1): 87–95.

[CH97] Castro, P., & M. E. Huber. 1997. Marine Biology 2nd ed. WCB McGraw-Hill: Boston.

[C02] Collette, B. B. 2002. Mackerels. Family Scombridae. In: Collette, B. B., & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine 3rd ed. pp. 516–536. Smithsonian Institute Press: Washington.

[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.

[G88] Gray, J. 1988. Evolution of the freshwater ecosystem: the fossil record. Palaeogeography, Palaeoclimatology, Palaeoecology 62: 1–214.

[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.

[LS09] Leclère, L., P. Schuchert, C. Cruaud, A. Couloux & M. Manuel. 2009. Molecular phylogenetics of Thecata (Hydrozoa, Cnidaria) reveals long-term maintenance of life history traits despite high frequency of recent character changes. Systematic Biology 58 (5): 509–526.

[PO99] Pagès, F., & C. Orejas. 1999. Medusae, siphonophores and ctenophores of the Magellan region. Scientia Marina 63 (Suppl. 1): 51–57.

[P79] Petersen, K. W. 1979. Development of coloniality in Hydrozoa. In: Larwood, G., & B. R. Rosen (eds) Biology and Systematics of Colonial Organisms pp. 105–139. Academic Press: London.

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