Hydrozoa

Hydrozoa (hydrozoans; from Ancient Greek ('''') 'water' and ('''') 'animals') is a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats. Hydrozoans are related to jellyfish and corals, which also belong to the phylum Cnidaria.

AI overview

Hydrozoans are tiny predatory animals that mostly live in saltwater, either alone or in colonies, and are closely related to jellyfish and corals. Some form large colonies where individual animals become so specialized they cannot survive on their own, making them important examples of how simple organisms can develop complex cooperative structures.

AI-generated from the Wikipedia summary — may contain errors.

Species

hydroids

Hydrozoa

CLASS

KingdomAnimalia
PhylumCnidaria
ClassHydrozoa

Habitatmarine, brackish, freshwater

Observations recorded1,265,515

via GBIF

Research

2,537 papers

Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds.Zootaxa · 2020Gil M, Ramil F, AgÍs JADOI: 10.11646/zootaxa.4878.3.2
Genome assembly of Bougainvillia cf. muscus (Cnidaria: Hydrozoa).G3 (Bethesda, Md.) · 2025Macias-Muñoz A, Varney R, Katcher E et al.DOI: 10.1093/g3journal/jkaf110
Hydrozoa metamorphosis and pattern formation.ReviewCurrent topics in developmental biology · 1998Berking SDOI: 10.1016/s0070-2153(08)60245-8
Extraction, purification and properties of aequorin, a bioluminescent protein from the luminous hydromedusan, Aequorea.Journal of cellular and comparative physiology · 1962SHIMOMURA O, JOHNSON FH, SAIGA YDOI: 10.1002/jcp.1030590302
Hydroids (Cnidaria, Hydrozoa) from Guinea Bissau.Zootaxa · 2025Gil M, Ramil FDOI: 10.11646/zootaxa.5577.1.1
Transcriptome Characterization of Reverse Development in Turritopsis dohrnii (Hydrozoa, Cnidaria).G3 (Bethesda, Md.) · 2019Matsumoto Y, Piraino S, Miglietta MPDOI: 10.1534/g3.119.400487
Global diversity and review of Siphonophorae (Cnidaria: Hydrozoa).ReviewPloS one · 2014Mapstone GMDOI: 10.1371/journal.pone.0087737
Global diversity of the Stylasteridae (Cnidaria: Hydrozoa: Athecatae).ReviewPloS one · 2011Cairns SDDOI: 10.1371/journal.pone.0021670

via PubMed

Wikidata facts

Image: Plumed hydroid5.jpg

Show 4 more facts

start time: 575000000-
Commons category: Hydrozoa
taxon name: Hydrozoa
taxon common name: hydrozoer

Sources (3)

via Wikidata · CC0

~11 min read

Article

8 sections

Contents

Anatomy
Polyps
Medusae
Life cycle
Systematics and evolution
Other classifications
References
External links

Some examples of hydrozoans are the freshwater jelly (Craspedacusta sowerbyi), freshwater polyps (Hydra), Obelia, Portuguese man o' war (Physalia physalis), chondrophores (Porpitidae), and pink-hearted hydroids (Tubularia).