{{Short description|Family of single-celled organisms}} {{Automatic taxobox | image = Bmc evol bio hoppenrath proterythropsis ocelloid fig1a.png | image_caption = A light micrograph of an ocelloid-containing dinoflagellate from the genus ''Proterythropsis''. The nucleus is marked '''n''', the ocelloid is indicated with a double arrowhead, and a posterior cell extension is indicated with an arrow; scale bar = 10 µm.<ref name=hoppenrath>{{cite journal|last1=Hoppenrath|first1=M|last2=Bachvaroff|first2=TR|last3=Handy|first3=SM|last4=Delwiche|first4=CF|last5=Leander|first5=BS|title=Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae) as inferred from SSU and LSU rDNA sequences.|journal=BMC Evolutionary Biology|date=25 May 2009|volume=9|issue=1|page=116|pmid=19467154|doi=10.1186/1471-2148-9-116|pmc=2694157|bibcode=2009BMCEE...9..116H|doi-access=free}}</ref> | image_alt = An image of a single cell featuring a large nucleus and an ocelloid, which is composed of a roundish "lens" and a darkly pigmented disc-shaped retinal body. | taxon = Warnowiaceae | authority = Lindemann, 1928<ref name=WoRMS/> | subdivision_ranks = Genera | subdivision = {{columns-list|colwidth=30em| *''Erythropsidinium'' *''Greuetodinium'' *''Nematodinium'' *''Nematopsides'' *''Proterythropsis'' *''Protopsis'' *''Warnowia'' }} }} The '''Warnowiaceae''' are a family of athecate dinoflagellates (a diverse group of unicellular eukaryotes). Members of the family are known as '''warnowiids'''. The family is best known for a light-sensitive subcellular structure known as the ocelloid, a highly complex arrangement of organelles with a structure directly analogous to the eyes of multicellular organisms. The ocelloid has been shown to be composed of multiple types of endosymbionts, namely mitochondria and at least one type of plastid.<ref name="gavelis">{{cite journal |title=Eye-like ocelloids are built from different endosymbiotically acquired components |author=Gregory S. Gavelis |author2=Shiho Hayakawa |author3=Richard A. White III |author4=Takashi Gojobori |author5=Curtis A. Suttle |author6=Patrick J. Keeling |author7=Brian S. Leander |journal=Nature |year=2015 |doi=10.1038/nature14593|pmid=26131935 |volume=523 |issue=7559 |pages=204–7|bibcode=2015Natur.523..204G |hdl=10754/566109 |s2cid=4462376 |hdl-access=free }}</ref>
==Habitat and life cycle== Warnowiids are found in marine plankton but are very rare in most plankton samples. Little is known about their life histories because they cannot be cultured in the laboratory, and samples obtained from the natural environment do not survive well under laboratory conditions. Studies of wild samples have found evidence of distinctive structures called trichocysts in warnowiid cell vacuoles, suggesting that their prey might be other dinoflagellates. Despite the complexity of the ocelloid, the experimental difficulty of working with the cells has prevented experimental study of light-directed behavior such as phototaxis.<ref name=gavelis />
==Taxonomy== The family contains seven recognized genera.<ref name=WoRMS>{{cite WoRMS |year=2026 |title=Warnowiaceae Lindemann, 1928 |id=109415 |access-date=8 March 2026 |db=AlgaeBase}}<small>{{A note|WoRMS incorrectly lists ''Ceratoperidinium'' as a warnowiid}}</small></ref> Descriptions of genera and species within the family have been complicated by complex morphological changes during the life cycle and in response to the environment, and the systematics of this group is not currently well defined.<ref name=hoppenrath />
==Subcellular structures== The warnowiids as a group possess unusually complex subcellular structures. The ocelloid light sensitive structure is recognized as a synapomorphic character of warnowiids.<ref name=hoppenrath />
Other complex subcellular structures, such as nematocysts, trichocysts, and pistons, are present in some (but not all) warnowiids and are shared with the polykrikoid dinoflagellates, the closest extant relatives as defined by molecular phylogenetics.<ref name=hoppenrath /><ref name=gomez>{{cite journal|last1=GÓMEZ|first1=FERNANDO|last2=LÓPEZ-GARCÍA|first2=PURIFICACIÓN|last3=MOREIRA|first3=DAVID|title=Molecular Phylogeny of the Ocelloid-Bearing Dinoflagellates and (Warnowiaceae, Dinophyceae)|journal=Journal of Eukaryotic Microbiology|date=September 2009|volume=56|issue=5|pages=440–445|doi=10.1111/j.1550-7408.2009.00420.x|pmid=19737196|s2cid=41132911}}</ref>
==Ocelloid function and origin== The ocelloid of warnowiids functions similarly to eyes found in much larger organisms, containing structures similar to a retina and lens. It is receptive only to the polarized light that is created as light passes through the thecal plates of other dinoflagellates.<ref name="gavelis" /> Because dinoflagellates are the main source of food for warnowiids, this trait is particularly useful for locating prey.
A modified plasmid acts as the retinal body.<ref>{{Cite journal | last1=Cooney | first1=EC | last2=Holt | first2=CC | last3=Jacko-Reynolds | first3=VKL | last4=Leander |first4=BS | last5=Keeling | first5=PJ | date=2023-10-09 | title=Photosystems in the eye-like organelles of heterotrophic warnowiid dinoflagellates | journal=Current Biology | volume=33 | issue=19 | pages=4252–4260 | doi=10.1016/j.cub.2023.08.052 | pmid=37703877 | doi-access=free }}</ref> A gene fragment that is expressed in the rhodopsin of the retinal body of the ocelloid has been shown to be most closely related to those of bacteria, suggesting a bacterial endosymbiont as the origin of the organelle.<ref>{{Cite journal|last1=Hayakawa|first1=Shiho|last2=Takaku|first2=Yasuharu|last3=Hwang|first3=Jung Shan|last4=Horiguchi|first4=Takeo|last5=Suga|first5=Hiroshi|last6=Gehring|first6=Walter|last7=Ikeo|first7=Kazuho|last8=Gojobori|first8=Takashi|date=2015-03-03|title=Function and Evolutionary Origin of Unicellular Camera-Type Eye Structure|journal=PLOS ONE|volume=10|issue=3|article-number=e0118415|doi=10.1371/journal.pone.0118415|pmid=25734540|pmc=4348419|bibcode=2015PLoSO..1018415H|issn=1932-6203|doi-access=free}}</ref>
==Gallery==
{{Gallery |title=Warnowiids |width=160 | height=170 |align=center |footer=Double arrows indicate the ocelloid, single arrow indicates the piston, '''n''' indicates the nucleus.<ref name=hoppenrath /> |File:Bmc evol bio hoppenrath Erythropsidinium ocelloid piston fig1r.png |alt1=Light micrograph of a cell, translucent pink with darkly pigmented ocelloid retinal body at upper left and light, straight piston projection at bottom center. |An isolate of ''Erythropsidinium''. Scale bar 20 µm. |File:Bmc evol bio hoppenrath Nematodinium ocelloid fig1m.png |alt2=Light micrograph of a cell, translucent brown, with lighter-stained nucleus in center and ocelloid visible at lower right as a light region (hyalosome) next to a dark region (retinal body). |An isolate of ''Nematodinium''. Scale bar 10 µm. |File:Bmc evol bio hoppenrath Warnowia ocelloid fig1g.png |alt3=Light micrograph of a cell, translucent with purple borders, with an ocelloid visible at lower right. |An isolate of ''Warnowia''. Scale bar 10 µm. }}
==References== {{Reflist|30em}}
==External links== * {{tolweb|126754|title=Warnowiaceae}}
{{Taxonbar|from=Q19785751}}
Category:Dinoflagellate families Category:Gymnodiniales