Bristle Worms, Sedentary and Tube-dwelling - Subclass: Sedentaria
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Sedentaria are the sister group to the Errantia but differ in a number of ways. Most tellingly, as their generic moniker suggests, they are fixed in place. Although able to swim freely as larvae, as adults they spend their lives mostly in tubes, buried or partially so, in the sediments. They have on average less segments than the Errantia and certain body regions - made up of a number of adjoining segments - may be specialsed to perform certain functions. Sedentaria lack jaws as they are deposit or filter feeders rather than active or opportunistic hunters.
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The Sedentaria are said to live in a 'marine interstitial' environment. This literally means they live 'in between the sand grains'. They burrow into the sand where they produce some kind of tube for themselves often made with the help of their own secretions. From an evolutionary point of view these kinds of organisms did not likely evolve from an archetype but rather via progresses of miniturisation and progenesis (= the adult form taking on the form and size of the juvenile or larvae as it evolves.
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Unfortunately the fossil record is rather poor in pre-historic sedentarid worms so exact times of their separation from their sister group is hard to ascertain. Furthermore, if they did evolve by either progenesis or miniaturisation it would be also hard to determine whether or not we were dealing with a Sedentarian or something else alltogether. Currently the Catologue of Life recognises nearly 5,800 species in 32 families. iNaturalist separates the subclass into two infraclasses and one unplaced family.
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Unplaced families
Family: Chaetopteridae
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Chaetopterus sp.
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Mesochaetopterus sp.
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Infraclass: Canalipalpata
Unplaced families
Family: Sabellariidae
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Gesaia sp.
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Idantharsys sp.
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Lygdamis sp.
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Phragmatopoma sp. (possible occurrence)
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Order: Sabellida
Family: Fabriciidae
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Genus ? (possible occurrence)
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Famiy: Sabellidae
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Amphicorina sp.
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Amphiglena sp.
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Branchiomma sp. (possible occurrence)
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Parasabella sp.
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Sabellastarte sp.
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Family: Serpulidae
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Bathyvermilia sp.
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Crucigera sp.
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Ficopomatus sp.
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Filograna sp. (likely occurrence)
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Galeolaria sp.
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Hyalopomatus sp.
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Hydroides sp.
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Josephella sp. (likely occurrence)
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Metavermilia sp.
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Pomatostegus sp. (likely occurrence)
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Protula sp.
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Pseudovermilia sp.
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Salmacina sp.
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Spirobranchus sp.
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Vermiliopsis sp. (possible occurrence)
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Subfamily: Spirorbinae (possible occurrence)
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Genus ?
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Family: Siboglinidae
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Osedax sp. (possible occurrence)
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Order: Spionida
Family: Poecilochaetidae
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Poecilochaetus sp.
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Family: Spionidae
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Boccardia sp.
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Bocardiella sp.
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Carazziella sp.
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Dipolydora sp.
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Laonice sp.
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Microspio sp.
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Polydura sp.
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Polydorella sp.
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Prionospio sp.
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Pseudopolydora sp.
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Scolelepis sp. (possible occurrence)
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Order: Terebellida
Suborder: Cirratuliformia
Family: Acrocirridae (likely occurrence)
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Genus ?
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Family: Cirratulidae
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Caulleriella sp.
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Cirriformia sp.
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Family: Flabelligeridae
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Daylithos sp.
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Flabelligera sp.
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Family: Sternaspidae
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Sternaspis sp. (likely occurrence)
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Suborder: Terebelliformia
Family: Ampharetidae
Subfamily: Ampharetinae
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Jugamphicteis sp. (possible occurrence)
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Family: Pectarinidae
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Lagis sp. (possible occurrence)
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Pectinaria sp.
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Family: Terebellidae
Subfamily: Terebellinae
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Amphitrite sp.
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Eupolymnia sp. (possible occurrence)
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Lanice sp.
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Lanicides sp.
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Loimia sp.
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Neoleprea sp.
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Pista sp.
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Reteterebella sp.
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Terebella sp.
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Tribe: Polycirrini
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Amaeana sp.
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Subfamily: Thelepodinae
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Thelepus sp.
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Family: Trichobranchidae
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Terebellides sp.
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Infraclass: Scolecida
Family: Arenicolidae
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Arenicola sp. (possible occurrence)
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Family: Capitellidae
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Barantolla sp. (likely occurrence)
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Capitella sp.
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Capitellethus sp. (possible occurrence)
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Leiochrides sp. (likely occurrence)
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Notomastus sp.
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Family: Cossuridae
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Cossura sp. (likely occurrence)
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Family: Maldanidae
Subfamily: Euclymeninae
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Axiothella sp.
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Subfamily: Maldaninae
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Maldane sp.
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Family: Opheliidae
Subfamily: Opheliinae
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Thoracophella sp. (possible occurrence)
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Subfamily: Ophelininae
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Armandia sp.
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Polyophthalmus sp.
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Family: Orbiniidae
Subfamily: Orbiniinae
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Leitoscoloplos sp.
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Leodamas sp. (possible occurrence)
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Felix sp.
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Scoloplos sp.
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Family: Paraonidae
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Levinsenia sp. (possible occurrence)
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Family: Scalibregmatidae
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Hyboscolex sp.
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Scalibregma sp.
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This concludes the Phyllum - Segmented Worms.
Taxonomy:
Phylum: Annelida (Segmented Worms)
> Class: Polychaeta (Polychaete Worms)
> Subclass: Sedentaria (Sedentary and Tube-dwelling Bristle Worms)
> Unplaced Families in the Subclass: Sedentaria
> Family: Chaetopteridae (Parchment Tubeworms)
> Genus: Chaetopterus
> Genus: Mesochaetopterus
>Infraclass: Canalipalpata
> Unplaced Families in the Infraclass: Canalipalpata
> Family: Sabellariidae
> Genus: Gesaia
> Genus: Idantharsys
> Genus: Lygdamis
> Genus: Phragmatopoma ^
> Order: Sabellida
> Family: Fabriciidae ^
> Family: Sabellidae (Feather Duster Worms)
> Subfamily: Sabellinae
> Genus: Amphicorina
> Genus: Amphiglena
> Genus: Branchiomma ^
> Genus: Parasabella
> Genus: Sabellastarte
> Family: Serpulidae (Serpulid Tubeworms)
> Genus: Bathyvermilia
> Genus: Crucigera
> Genus: Ficopomatus
> Genus: Filograna *
> Genus: Galeolaria
> Genus: Hyalopomatus
> Genus: Hydroides
> Genus: Josephella *
> Genus: Metavermilia
> Genus: Pomatostegus *
> Genus: Protula
> Genus: Pseudovermilia
> Genus: Salmacina
> Genus: Spirobranchus (Christmas Tree Worms)
> Genus: Vermiliopsis ^
> Subfamily: Spirorbinae ^ (Spiral Tube Worms)
> Family: Siboglinidae (Beard Worms)
> Genus: Osedax ^
> Order: Spionida
> Suborder: Spioniformia
> Family: Poecilochaetidae
> Genus: Poecilochaetus
> Family: Spionidae
> Genus: Boccardia
> Genus: Boccardiella
> Genus: Carazziella
> Genus: Dipolydora
> Genus: Laonice
> Genus: Microspio
> Genus: Polydura
> Genus: Polydorella
> Genus: Prionospio
> Genus: Pseudopolydora
> Genus: Scolelepis ^
> Order: Terebellida
> Suborder: Cirratuliformia
> Family: Acrocirridae *
> Family: Cirratulidae
> Genus: Caulleriella
> Genus: Cirriformia (Thread-gilled Worms)
> Family: Flabelligeridae
> Genus: Daylithos
> Genus: Flabelligera
> Family: Sternaspidae
> Genus: Sternaspis *
> Suborder: Terebelliformia
> Family: Ampharetidae
> Subfamily: Ampharetinae
> Genus: Jugamphicteis ^
> Family: Pectarinidae
> Genus: Lagis ^
> Genus: Pectinaria
> Family: Terebellidae (Spaghetti Worms)
> Subfamily: Terebellinae
> Genus: Amphitrite
> Genus: Eupolymnia ^
> Genus: Lanice
> Genus: Lanicides
> Genus: Loimia
> Genus: Neoleprea
> Genus: Pista
> Genus: Reteterebella
> Genus: Terebella
> Tribe: Polycirrini
> Genus: Amaeana
> Subfamily: Thelepodinae
> Genus: Thelepus (Tangleworms)
> Family: Trichobranchidae
> Genus: Terebellides
>Infraclass: Scolecida
> Family: Arenicolidae (Lugworms)
> Genus: Arenicola ^
> Family: Capitellidae
> Genus: Barantolla *
> Genus: Capitella
> Genus: Capitellethus ^
> Genus: Leiochrides *
> Genus: Notomastus
> Family: Cossuridae
> Genus: Cossura *
> Family: Maldanidae (Bamboo Worms)
> Subfamily: Euclymeninae
> Genus: Axiothella
> Subfamily: Maldaninae
> Genus: Maldane
> Family: Opheliidae
> Subfamily: Opheliinae
> Genus: Thoracophella ^
> Subfamily: Ophelininae
> Genus: Armandia
> Genus: Polyophthalmus
> Family: Orbiniidae
> Subfamily: Orbiniinae
> Genus: Leitoscoloplos
> Genus: Leodamas ^
> Genus: Felix
> Genus: Scoloplos
> Family: Paraonidae *
> Genus: Levinsenia *
> Family: Scalibregmatidae (Maggot Worms)
> Genus: Hyboscolex
> Genus: Scalibregma
* = likely
^ = possibly
References and links:
> Glasby, C.J., Erséus, C., and Martin, P., (2021). 'Annelids in Extreme Aquatic Environments: Diversity, Adaptations and Evolution.' Diversity 13, no. 2: 98. doi.org/10.3390/d13020098
> Lamarck, J.B., (1818). [volume 5 of] 'Histoire naturelle des Animaux sans Vertèbres, préséntant les caractères généraux et particuliers de ces animaux, leur distribution, leurs classes, leurs familles, leurs genres, et la citation des principales espèces qui s’y rapportent; precedes d’une Introduction offrant la determination des caracteres essentiels de l’Animal, sa distinction du vegetal et desautres corps naturels, enfin, l’Exposition des Principes fondamentaux de la Zoologie.' Paris, Deterville, vol 5.
https://www.marinespecies.org/polychaeta/aphia.php?p=sourcedetails&id=50747
> Struck, T.H., Golombek, A., Weigert, A., Franke, F.A., Westheide, W., Purschke, G., Bleidorn, C. and Halanych, K.M., (2015). 'The Evolution of Annelids Reveals Two Adaptive Routes to the Interstitial Realm.' Current Biology, Volume 25, Issue 15, 2015, Pages 1993-1999, ISSN 0960-9822, https://doi.org/10.1016/j.cub.2015.06.007.
https://www.catalogueoflife.org/data/taxon/cf55fc39-d78f-4a17-8fa5-0f211aefd4a1
https://inaturalist.ala.org.au/taxa/551647-Sedentaria
> Glasby, C.J., Erséus, C., and Martin, P., (2021). 'Annelids in Extreme Aquatic Environments: Diversity, Adaptations and Evolution.' Diversity 13, no. 2: 98. doi.org/10.3390/d13020098
> Lamarck, J.B., (1818). [volume 5 of] 'Histoire naturelle des Animaux sans Vertèbres, préséntant les caractères généraux et particuliers de ces animaux, leur distribution, leurs classes, leurs familles, leurs genres, et la citation des principales espèces qui s’y rapportent; precedes d’une Introduction offrant la determination des caracteres essentiels de l’Animal, sa distinction du vegetal et desautres corps naturels, enfin, l’Exposition des Principes fondamentaux de la Zoologie.' Paris, Deterville, vol 5.
https://www.marinespecies.org/polychaeta/aphia.php?p=sourcedetails&id=50747
> Struck, T.H., Golombek, A., Weigert, A., Franke, F.A., Westheide, W., Purschke, G., Bleidorn, C. and Halanych, K.M., (2015). 'The Evolution of Annelids Reveals Two Adaptive Routes to the Interstitial Realm.' Current Biology, Volume 25, Issue 15, 2015, Pages 1993-1999, ISSN 0960-9822, https://doi.org/10.1016/j.cub.2015.06.007.
https://www.catalogueoflife.org/data/taxon/cf55fc39-d78f-4a17-8fa5-0f211aefd4a1
https://inaturalist.ala.org.au/taxa/551647-Sedentaria
Photographic contributions: