The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into segments, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described.[4]
Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable proboscis which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre.
Most are deposit feeders, collecting detritus from the sea floor. Fossils of these worms are seldom found and the earliest known fossil specimen is from the Upper Carboniferous (Pennsylvanian).
^Jones, D.; Thompson, I. D. A. (1977). "Echiura from the Pennsylvanian Essex Fauna of northern Illinois". Lethaia. 10 (4): 317. doi:10.1111/j.1502-3931.1977.tb00627.x.
^Cite error: The named reference EncycloBrit was invoked but never defined (see the help page).
^Tanaka, Masaatsu (2017). "Echiura". WoRMS. World Register of Marine Species. Retrieved 17 February 2019.
^Zhang, Z.-Q. (2011). "Animal biodiversity: An introduction to higher-level classification and taxonomic richness" (PDF). Zootaxa. 3148: 7–12. doi:10.11646/zootaxa.3148.1.3. Archived (PDF) from the original on 2022-10-09.
The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids...
oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded...
Kenneth M (5 April 2007). "Annelid phylogeny and the status of Sipuncula and Echiura". BMC Evolutionary Biology. 7 (1): 57. doi:10.1186/1471-2148-7-57. PMC 1855331...
high as 58,000 per square meter (5,390 per square foot). Together with Echiura and Sipuncula, they were once placed in the taxon Gephyrea, but consistent...
Schembri, David S. Boukal (2005). Sex determination in Bonellia viridis (Echiura: Bonelliidae): population dynamics and evolution Archived 2005-04-11 at...
within Sedentaria are: Clitellata, the Sabellida/Spionida clade, Opheliida, Echiura, Cirratuliformia, Terebelliformia, Maldanomorpha and the families Siboglinidae...
Patrick J.; Boukal, David S. (2005). "Sex determination in Bonellia viridis (Echiura: Bonelliidae): population dynamics and evolution" (PDF). Oikos. 108 (3):...
List of annelid families describes the taxa relationships in the phylum Annelida, which contains more than 17,000 extant species including ragworms, earthworms...
† Nemertea Phoronida Bryozoa Entoprocta Brachiopoda Mollusca Annelida Echiura Mesomycetozoa Fungi – any member of the group of eukaryotic organisms that...
epidermal cells and epidermal gland cells are also found in Ctenophora, Echiura, Sipuncula, Annelida, Mollusca and other taxa. The rhabdites of nemertea...
Kenneth M. (2007-01-01). "Annelid phylogeny and the status of Sipuncula and Echiura". BMC Evolutionary Biology. 7 (1): 57. Bibcode:2007BMCEE...7...57S. doi:10...
Bonelliidae is a family of marine worms (Subclass Echiura, of the class Polychaeta, in the phylum Annelida) noted for being sexually dimorphic, with males...
innkeeper" or "penis fish") is a family of spoonworms in the subclass Echiura. The only genus in the family is Urechis, which has four species. The World...
Halanych, K. M. (2007). "Annelid phylogeny and the status of Sipuncula and Echiura". BMC Evolutionary Biology. 7: 57. doi:10.1186/1471-2148-7-57. PMC 1855331...
now-dismantled class of marine worms, containing the three modern taxa Echiura, Sipuncula, and Priapulida. Also Sternaspis, the first described genus...
at the back. Like most annelids, with a few exceptions like Sipuncula, Echiura and Diurodrilus, the leech is a segmented animal, but unlike other annelids...
Questida (nomen dubium) Order Scolecidaformia (nomen dubium) Subclass Echiura Order Bonelliida Family Bonelliidae Family Ikedidae Order Echiurida Family...
tomboyish character. Before PGSM, she played a lead role in a video for Echiura's song "Taisetsu na omoide". In October 2006, she won the 38th "non-no model...
sea urchins, sand dollars, sea cucumbers, crinoids, and sea daisies; Echiura, also known as spoon worms; Gnathostomulids, slender to thread-like worms...
crabs, lobsters and shrimps (Crustacea), and little known groups such as Echiura, Priapulida, Sipuncula, Brachiopoda, Pogonophora, Phoronida, and Hemichordata...
layer, and as this was at odds with all other members of the subclass Echiura, it warranted the creation of a new order. However, examination of the...
worms including the phyla Platyhelminthes, Nemertea, Annelida, Sipuncula, Echiura, Chaetognatha, and Phoronida; Mollusca including shellfish, squid, octopus;...
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