Bristle Worms, Active Free-living - Subclass: Errantia
Of the three subclasses within the Polychaeta the marine subclasses Errantia and Sedentaria are different from each other in whether or not the worm is either vagile (= can swim freely about) or is sessile (= restricted to living in one fixed place, in this case, in a tube).
Arranging taxons by behaviours does not appear to be satisfactory of course, but, various recent studies have indeed supported the idea. Currently the Encyclopedia of Life counts some 6,000 species in 626 genera in 42 families. The Errantia enjoy a worldwide distribution with recent records even existing from both Arctic and Antarctic waters. The Northern Rivers has its' fair share of species with all three orders within the Errantia represented. |
The Errantia are free-swimming or crawling predators that may burrow to protect themselves. Their body segments are all quite similar except for those at either end. Their prostomium - the 'head' - is quite easily distinguished and it contains sensory organs such as palps and antennae. Nuchal organs (= light sensing organs), usually 2 - 4 pairs, can] be found between the prostomium and the first segment. The pharynx (= throat) can be extended outwards thereby freeing the jaws which are used to grab the prey. Compared to their tube-dwelling relatives, the Errantia , on average are smaller. Many do not get bigger than 10 - 15 cm in length and have parapodia protruding from each body segment.
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Taxonomy:
Phylum: Annelida (Segmented Worms)
> Class: Polychaeta (Polychaete Worms)
> Subclass: Errantia (Active Free-living Bristleworms)
> Order: Amphinomida
> Family: Amphinomidae
> Subfamily: Amphinominae
> Genus: Amphinome
> Genus: Eurythoe
> Subfamily: Archinominae
> Genus: Bathychloeia
> Genus: Chloeia ^
> Genus: Notopygus
> Family: Euphrosinidae
> Genus: Euphrosine
> Order: Eunicida
> Family: Dorvilleidae
> Genus: Dorvillea ^
> Genus: Ophryotrocha ^
> Genus: Schistomeringos ^
> Family: Eunicidae
> Genus: Eunice
> Genus: Leodice
> Genus: Lysidice
> Genus: Marphysa
> Genus: Nicidion
> Genus: Palola
> Family: Lumbrineridae
> Genus: Lumbrineris
> Family: Oenonidae
> Genus: Arabella
> Genus: Drilonereis ^
> Genus: Halla ^
> Genus: Oenone
> Family: Onuphidae (Beachworms)
> Subfamily: Hyalinoeciinae
> Genus: Hyalinoecia
> Genus: Nothria
> Subfamily: Onuphinae
> Genus: Australonuphis
> Genus: Diopatra (Decorator Worms)
> Genus: Hirsutonuphis
> Genus: Onuphis
> Order: Phyllodocida
> Unplaced Families in the Order: Phyllodocida
> Family: Nephtyidae
> Genus: Aglophamus
> Genus: Nephtys
> Family: Sphaerodoridae
> Genus: Sphaerodoropsis
> Suborder: Aphroditiformia
> Family: Acoetidae ^
> Family: Aphroditidae
> Genus: Aphrodita
> Genus: Laetmonice
> Family: Iophonidae
> Genus: Iophone
> Family: Polynoidae (Scaleworms)
> Subfamily: Lepidastheniinae
> Genus: Lepidasthenia ^
> Subfamily: Lepidomotinae
> Genus: Lepidonotus
> Genus: Thormora
> Subfamily: Macellicephalinae
> Genus: Macellicephala
> Subfamily: Polynoinae
> Genus: Harmothoe
> Family: Sigalionidae
> Unplaced Genera in Family: Sigalonidae
> Genus: Sigalion
> Genus: Sthenelais
> Subfamily: Pelogiinae
> Genus: Pelogenia *
> Subfamily: Sigalioninae
> Genus: Euthalenessa
> Suborder: Glyceriformia
> Family: Glyceridae
> Genus: Glycera
> Genus: Hemipodia
> Family: Goniadidae
> Genus: Glycinde
> Genus: Goniada *
> Genus: Progoniada
> Suborder: Nereidiformia
> Family: Chrysopetalidae
> Subfamily: Chrysopetalinae
> Genus: Chrysopetalum ^
> Family: Hesionidae
> Subfamily: Hesioninae
> Tribe: Hesionini
> Genus: Hesione
> Genus: Leocrates
> Subfamily: Psamathinae
> Genus: Micropodarke
> Family: Nereididae
> Subfamily: Gymnonereidindae
> Genus: Australonereis
> Genus: Websterinereis
> Subfamily: Namanereidinae
> Genus: Namalycastis
> Subfamily: Nereidinae
> Genus: Ceratonereis
> Genus: Leonnates
> Genus: Neanthes
> Genus: Nereis
> Genus: Perinereis
> Genus: Platynereis
> Genus: Pseudonereis
> Genus: Simplisetia
> Family: Pilargidae
> Subfamily: Pilarginae
> Genus: Sigambra
> Family: Syllidae
> Subfamily: Eusyllinae
> Genus: Eusyllis
> Genus: Odontosyllis
> Genus: Paraehlersia
> Subfamily: Exogoninae
> Genus: Brania
> Genus: Erinaceusyllis
> Genus: Exogone
> Genus: Parasphaerosyllis
> Genus: Salvatoria
> Genus: Sphaerosyllis
> Subfamily: Syllinae
> Genus: Branchiosyllis ^
> Genus: Haplosyllis (Spongeworms)
> Genus: Megasyllis
> Genus: Syllis
> Genus: Trypanosyllis
> Genus: Typosyllis *
> Suborder: Phyllodociformia
> Family: Lopadorrhynchidae
> Genus: Pelagobia
> Family: Phyllodocidae (Paddle Worms)
> Subfamily: Eteoninae
> Genus: Eteone ^
> Genus: Eumida
> Subfamily: Notophyllinae
> Genus: Nereiphylla
> Subfamily: Phyllodocinae
> Genus: Phyllodoce
* = likely
^ = possibly
References and links:
> Weigert, A. and Bleidorn, C., (2016). 'Current status of annelid phylogeny.' Organisms Diversity & Evolution. 16. DOI: 10.1007/s13127-016-0265-7.
https://eol.org/pages/39694098
https://inaturalist.ala.org.au/observations/59170113
https://microbenotes.com/phylum-annelida/#subclass-1-errantia
https://en.wikipedia.org/wiki/Nuchal_organ
https://en.wikipedia.org/wiki/Parapodium
https://en.wikipedia.org/wiki/Prostomium
> Weigert, A. and Bleidorn, C., (2016). 'Current status of annelid phylogeny.' Organisms Diversity & Evolution. 16. DOI: 10.1007/s13127-016-0265-7.
https://eol.org/pages/39694098
https://inaturalist.ala.org.au/observations/59170113
https://microbenotes.com/phylum-annelida/#subclass-1-errantia
https://en.wikipedia.org/wiki/Nuchal_organ
https://en.wikipedia.org/wiki/Parapodium
https://en.wikipedia.org/wiki/Prostomium
Text:
Erik Beringen.
Erik Beringen.
Photographic contributions: