Namanereidinae

{{Short description|Subfamily of bristleworms}} {{Automatic taxobox | taxon = Namanereidinae | authority = Hartman, 1959 | image = Namanereis llanetensis (10.3897-subtbiol.36.55090) Figure 1 (cropped).jpg | image_caption = ''[[Namanereis llanetensis]]'' | subdivision_ranks = Species | subdivision = * ''[[Namalycastis]]'' * ''[[Namanereis]]'' | type_genus = Namanereis | type_genus_authority = Chamberlin, 1919 | synonyms = * Lycastinae Corrêa, 1948 * Namanereinae Hartman, 1959 | synonyms_ref = <ref name=WoRMS>{{Cite WoRMS|title=Namanereidinae Hartman, 1959|id=324345|access-date=2025-10-14|db=Polychaeta}}</ref> }} '''Namanereidinae''' is a [[subfamily]] of nereidid [[polychaete worm]]s which are adapted to live in habitats of low [[salinity]], unlike most other polychaetes which inhabit [[marine environment]]s.<ref name="Gran"/> According to the [[World Register of Marine Species]], there are 50 [[Valid name (zoology)|valid species]] in two genera; a third genus, ''Lycastoides'' is a [[taxon inquirendum]] due to the loss of its [[type specimen]].<ref name=WoRMS/> They are found from the [[tropics]] to [[high latitude]]s, and inhabit [[Intertidal ecology|intertidal]] areas (such as [[mangrove]]s and [[Salt marsh|saltmarsh]]es)<ref name="Monog1"/><ref>{{cite journal |last1=Islam |first1=M. Shafiqul |last2=Zamal |first2=Hossain |last3=Alam |first3=Muhammad Shah |last4=Bappy |first4=Md. Maheen Mahmud |last5=Kamal |first5=Abu Hena Mustafa |last6=Hossain |first6=M. Belal |last7=Arai |first7=Takaomi |title=Biodiversity and Seasonal Succession of Macrobenthos in Saltmarsh Habitat Adjacent to a Ship-Breaking Area |journal=Diversity |date=25 March 2025 |volume=17 |issue=4 |page=231 |doi=10.3390/d17040231 |doi-access=free }}</ref> to "uplifted coastal areas"; a number of species are [[Hypogeal|hypogean]] [[stygobiont]]s, inhabiting [[groundwater]] and exhibiting the typical features of cave animals, such as [[Animal coloration|skin depigmentation]] and eyelessness.<ref name="Gran"/><ref name="Trogcola"/> Various species are known to associate with plants (especially the damp areas such as [[phytotelmata]]) and plant debris, and they seem to prefer these habitats.<ref name="Monog1"/>

==Taxonomy== The [[scientific name]]s of both genera combine the Ancient Greek word ''nama-'', meaning [[Spring (hydrology)|spring]] or [[stream]], with ''[[Lycastis]]'' and ''[[Nereis]]'', being two scientific names used for nereidid worms. Both [[Generic name (biology)|generic name]]s thus allude to the freshwater habitats that are inhabited by some species in the subfamily.<ref name="Monog1"/>

Prior to modern [[phylogenetic analyses]], namanereidines were considered to be the [[sister group]] to all other Nereididae; a 2020 analysis of nereidid [[mitogenome]]s did recover ''[[Namalycastis abiuma]]'' in a [[Basal (phylogenetics)|basal position]], but it was not the most "[[Primitive (phylogenetics)|primitive]]" nereidid in the analysis.<ref>{{cite journal |title=The phylogeny of Nereididae (Annelida) based on mitochondrial |journal=Zoologica Scripta |date=12 January 2020 |volume=49 |pages=366–378 |doi=10.1111/zsc.12413}}</ref>

''Namalycastis'' species tend to be larger-bodied than those of ''Namanereis'', possesses four pairs of tentacular cirri, short and subconical antennae, along with "flattened and leaf-like posterior [[cirrophore]]s". In contrast, ''Namanereis'' is smaller, has three pairs of tentacular cirri, no dorsal cirrophores nor [[notosetae]], and a "tripartite [[wikt:pygidium|pygidium]].<ref name="Monog1"/> Features of the setae and their rows/bundles (fascicles) are essential in identifying both genus and species<ref name="Monog1"/>

==Description== Members of Namanereidinae are [[Species diagnosis|diagnosed]] through the presence of paired lateral [[Antenna (zoology)|antenna]]e (though some species lack these), the [[wikt:larynx|larynx]] being divided into oral and maxillary rings though lacking [[wikt:paragnath|paragnath]]s or papillae, biarticulated [[palp]]s with compact [[wikt:palpophore|palpophore]]s, 3-4 pairs of [[Cirrus (biology)|cirri]] on the tentacles, along with the "[[Parapodium|parapodia]] reduced to [[wikt:sesquiramous|sesquiramous]] with [[notopodia]] reduced, lacking notopodial lobe or [[ligule]]s and showing only dorsal cirri and [[wikt:notoacicula|notoacicula]]e; [[notochaetae]] as [[wikt:sesquigomph|sesquigomph]] [[wikt:spiniger|spiniger]]s; [[neurochaetae]] including sesquigomph spinigers, heterogomph [[wikt:falciger|falciger]]s and heterogomph spinigers in supra-acicular fascicles; heterogomph spinigers, heterogomph pseudospinigers and heterogomph falcigers in sub-acicular fascicles".<ref>{{cite web |title=Namanereidinae Hartman, 1959: 160 |url=https://treatment.plazi.org/id/038D87F9-BA24-FFFE-5C86-FF420925F959 |website=publication.plazi.org |publisher=Plazi |access-date=18 October 2025}}</ref> In all members of the subfamily, the [[distal]] region of the palp, the palpostyle, is spherical in shape, and the notoacicula are placed [[ventrally]].<ref name="Monog1"/>

A number of adaptations to prevent [[desiccation]] is seen in various namanereidines, especially those inhabiting low-salinity and [[semi-terrestrial]] environments; these are evident in the eyes along with the [[integument]] and [[epidermis]]. Adaptations to low-oxygen may also be present, such as segmental [[gill]] hearts, leaf-like dorsal cirri rich in [[capillaries]], and a behavior of waving the posterior segments in water.<ref name="Monog1"/> Their [[Nephridium|nephridia]] appears to be an important part of their [[Osmoregulation|osmoregulatory]] process through the expulsion of excess water from their bodies.<ref>Krishnan G. (1952) On the nephridia of Nereidae in relation to habitat. Proceedings of the National Institute of Science, India 18: 241–255.</ref><ref name="Monog1"/> [[File:Namanereidinae (10.3897-subtbiol.23.13701) Figure 7.jpg|350px|thumb|Proposed evolutionary sequence of jaws in Namanereidinae, with (A) being an ancestral nereidid and (F) being [[Derived (phylogenetics)|derived]] namanereidines with bifid jaws.]] The only known description of a [[larva]] is of a 3-setiger stage of ''N. ranauensis'', which closely resembled other larval nereidids, such as in the possession of biramous parapodia.<ref name="Monog1"/>

Some species evolved bifid jaws, developed from the ancestral nereidid [[serrated]] jaw, which may be an adaptation for deposit-feeding ("shoveling"), due to energetic costs or lack of certain trace elements needed to harden the jaw elements, and/or other adaptations necessary when colonizing semi-terrestrial and groundwater habitats.<ref name="Trogcola">{{cite journal |last1=Conde-Vela |first1=Víctor Manuel |title=The troglomorphic adaptations of Namanereidinae (Annelida, Nereididae) revisited, including a redescription of Namanereis cavernicola (Solís-Weiss & Espinasa, 1991), and a new Caribbean species of Namanereis Chamberlin, 1919 |journal=Subterranean Biology |date=September 2017 |volume=23 |issue=1 |pages=19–28 |doi=10.3897/subtbiol.23.13701 |doi-access=free }}</ref>

==Distribution== The modern, widespread distribution of ''Namanereis'' may suggest [[vicariance]] from the breakup of [[Gondwana]] in the [[Late Jurassic]]. Alternatively, it may indicate [[speciation]] from marine ''Namanereis'' ancestors which independently colonized inland environments.<ref name="Gran">{{cite journal |last1=Núñez |first1=Jorge |last2=Glasby |first2=Christopher J. |last3=Naranjo |first3=Manuel |title=Groundwater annelids from Gran Canaria and Fuerteventura (Canary Islands), with the description of two new species of Namanereis (Namanereidinae, Nereididae, Polychaeta) |journal=Subterranean Biology |date=16 November 2020 |volume=36 |pages=35–49 |doi=10.3897/subtbiol.36.55090 |doi-access=free }}</ref> [[Plesiomorphic]] features in the marine species seems to support the latter theory; that being the ancestral namanereidine inhabited [[coast]]al, [[euryhaline]] habitats.<ref name="Monog1"/>

In any case, [[Endemism|endemic]] namanereidines are found in the [[Caribbean]],<ref name="Trogcola"/> the [[Canary Islands]],<ref name="Gran"/> India,<ref>{{cite journal |last1=Magesh |first1=Mathan |last2=Kvist |first2=Sebastian |last3=Glasby |first3=Chris |title=Description and phylogeny of Namalycastis jaya sp. n. (Polychaeta, Nereididae, Namanereidinae) from the southwest coast of India |journal=ZooKeys |date=November 5, 2012 |issue=238 |pages=31–43 |doi=10.3897/zookeys.238.4014 |doi-access=free |pmid=23226706 |pmc=3496943 }}</ref> [[Socotra]], and Australia.<ref>{{cite journal |last1=Glasby |first1=Christopher J. |last2=Fiege |first2=Dieter |last3=Van Damme |first3=Kay |title=Stygobiont polychaetes: notes on the morphology and the origins of groundwater Namanereis (Annelida: Nereididae: Namanereidinae), with a description of two new species |journal=Zoological Journal of the Linnean Society |date=1 May 2014 |volume=171 |issue=1 |pages=22–37 |doi=10.1111/zoj.12130}}</ref>

''[[Namalycastis hawaiiensis]]'' is known to be [[Introduced species|introduced]] to countries outside its native habitat; with a broad [[Species distribution|natural distribution]] in the [[Indo-Pacific]] from [[Sumatra]] to [[Hawaii]], and from the [[Ryukyus]] to [[Papua New Guinea]],<ref name="BHL"/> it has been identified in the aquarium trade in mainland Japan and Australia, and is thought to have established a population in the Sa'adya stream, which feeds into the [[Kishon River]].<ref>{{cite journal |last1=Goren |first1=Liron |last2=Feldstein |first2=Tamar |last3=Hershkovitz |first3=Yaron |title=First report of the non-native freshwater polychaete Namalycastis hawaiiensis (Johnson, 1903) (Nereididae: Namanereidinae) in Israel |journal=BioInvasions Records |date=5 March 2020 |volume=9 |issue=2 |pages=303–309 |doi=10.3391/bir.2020.9.2.15 |url=https://www.reabic.net/journals/bir/2020/2/BIR_2020_Goren_etal.pdf |access-date=18 October 2025}}</ref> Conversely, the temperate species inhabit the [[North Island]], along with [[subantarctic]] locales such as the [[Strait of Magellan]], [[Auckland Island]], [[Adams Island (New Zealand)|Adams Island]], and [[Campbell Island, New Zealand|Campbell Island]].<ref name="Monog1"/>

==Habitat== Across the species, namanereidines can tolerate [[Salinity|salinities]] from [[Fresh water|fresh]]/[[potable water]] to hypersaline conditions of 13% salinity.<ref name="Monog1"/>

Namanereidines are [[deposit feeder]]s, though they also consume small invertebrates.<ref name="Gran"/> Most species are found in association with plant [[detritus]], such as dead wood and leaves, which may provide food and protect the worms from desiccation.<ref name="Monog1"/> One species is capable of inhabiting the [[axil]]s of ''[[Pandanus]]'' trees,<ref name="BHL">{{cite journal |last1=Glasby |first1=Christopher John |last2=Mogi |first2=Motoyoshi |last3=Takahashi |first3=Kei-Ichi |title=Occurrence of the polychaete Namalycastis hawaiiensis Johnson, 1903 (Nereididae: Namanereidinae) in Pandanus Leaf Axils on Palau, West Pacific |journal=The Beagle: Records of the Museums and Art Galleries of the Northern Territory |date=December 2012 |volume=19 |pages=97–99 |doi=10.5962/p.286313 |url=https://www.biodiversitylibrary.org/part/286313 |access-date=21 October 2025|doi-access=free }}</ref><ref>{{cite journal |title=Short communication Occurrence of the polychaete Namalycastis hawaiiensis Johnson, 1903 (Nereididae: Namanereidinae) in Pandanus leaf axils on Palau, West Pacific |journal=The Beagle: Records of the Museums and Art Galleries of the Northern Territory |date=December 2003 |volume=19 |doi=10.5962/p.286313|doi-access=free }}</ref><ref>{{cite web |last1=Read |first1=Geoff |title=Namanereidinae (Polychaeta: Nereididae) The monograph of Chris Glasby About the Namanereidinae |url=https://www.annelida.net/docs/namanereid.html |website=annelida.net |access-date=21 October 2025}}</ref> and several species associate with the [[Nypa fruticans|Nypa palm]].<ref>{{cite journal |last1=Ibrahim |first1=Nur Fazne |last2=Ibrahim |first2=Yusof Shuaib |last3=Kan |first3=Kotaro |last4=Sato |first4=Masanori |title=Nereidid polychaetes (Annelida) inhabiting the inside of decaying fronds of the mangrove palm Nypa fruticans in a tropical estuary in Malaysia, with special reference to the life history of the dominant species, Namalycastis sp. |journal=Journal of Natural History |date=December 2024 |volume=58 |issue=45–48 |pages=2043–2074 |doi=10.1080/00222933.2024.2404472}}</ref> Still some other species inhabit the [[leaf litter]] of [[mangrove forest]]s, a "[[semiterrestrial]]" environment.<ref>{{cite journal |last1=Conde-Vela |first1=Víctor Manuel |title=Namalycastis occulta n. sp. and a new record of N. borealis (Polychaeta: Nereididae: Namanereidinae) from the Northwestern Caribbean Sea |journal=Zootaxa |date=17 October 2013 |volume=3721 |issue=5 |pages=475–487 |doi=10.11646/zootaxa.3721.5.3}}</ref><ref name="Trogcola"/> ''[[Namalycastis borealis]]'' eats wood, being a [[Xylophagy|xylophage]].<ref name="Monog1"/>

Their detritivorous habit may lead to the ingestion of [[microplastics]].<ref>{{cite journal |last1=Hamzah |first1=Siti Rabaah |last2=Altrawneh |first2=Ra'ad Shaher |last3=Anuar |first3=Sabiqah Tuan |last4=Khalik |first4=Wan Mohd Afiq Wan Mohd |last5=Kolandhasamy |first5=Prabhu |last6=Ibrahim |first6=Yusof Shuaib |title=Ingestion of microplastics by the estuarine polychaete, Namalycastis sp. in the Setiu Wetlands, Malaysia. |journal=Marine Pollution Bulletin |date=June 15, 2021 |volume=170 |article-number=112617 |doi=10.1016/j.marpolbul.2021.112617 |pmid=34139586}}</ref> A number of species are seemingly highly resistant to the effects of [[pollutant]]s, such as [[industrial waste]],<ref>Gibbs, P.E., & J.I. Saiz Salinas, 1996. The occurrence of the estuarine polychaete Lycastopsis littoralis (Namanereidinae: Nereididae) in the Ría de Bilbao, northern Spain. Journal of the Marine Biological Association of the United Kingdom 76: 617–623.</ref> [[Persistent organic pollutant|organics]],<ref>Kalaiselvi, R., & K. Ayyakkannu, 1986. Aspects of the ecology of Lycastis sp. (Polychaeta: Nereididae) from the southeast coast of India. In Proceedings of the 2nd International Polychaete Conference, Copenhagen. Ophelia, Supplement 5, eds. M.E. Petersen & J.B. Kirkegaard, p. 696.</ref><ref>Jaweir, H.J., 1987. Namalycastis indica, (Annelida: Polychaeta) a new record from Iraq. Journal of Biological Sciences Research, Baghdad 18(1): 229–230.</ref> [[hydrocarbon]]s,<ref>Jaweir, H.J., & A.H. Habash, 1987. Toxicity of water-soluble hydrocarbons of kerosene to polychaeaous [sic] annelides from Shat Al-Arab. Journal of Biological Science Research, Baghdad 18(2): 111–121.</ref> and [[heavy metals]].<ref>Varshney, P.K., & S.A.H. Abidi, 1988. Toxicity of mercury, copper and lead in the polychaete Namanereis meraukensis Horst. Indian Journal of Marine Sciences 17: 83–84.</ref><ref>Athalye, P.R., & K.S. Gokhale, 1991. Heavy metals in the polychaete Lycastis ouanaryensis from Thane Creek, India. Marine Pollution Bulletin 22(5): 233–236.</ref><ref name="Monog1">{{cite book |last1=Glasby |first1=Christopher J. |title=The Namanereidinae (Polychaeta: Nereididae). Part 1, Taxonomy and Phylogeny |date=1999 |publisher=Records of the Australian Museum, Supplement 25 |isbn=0-7313-8856-9 |url=https://media.australian.museum/media/Uploads/Journals/17869/1354_complete.pdf |access-date=21 October 2025}}</ref>

==References== {{reflist}}

[[Category:Polychaetes]]