Echiura
/ˌɛkɪˈjʊ(ə)rə
/plural noun Zoology
A small phylum of worm-like marine invertebrates that comprises the spoonworms.They are found in many animal taxa including Ctenophora, Echiura, Sipuncula, Annelida Mollusca among others....
- Rouse chose as terminal taxa for his analysis most of the accepted polychaete families, and in addition Clitellata, Rotifera, Platyhelminthes, Nemertea, Mollusca, Sipuncula, Echiura, and Entoprocta.
- When the character scoring between these studies is compared, one finds no debate about character scoring for phyla such as Mollusca, Sipuncula, Echiura, and Entoprocta, all scored present for a prototroch.
Derivatives
echiuran
- I conclude that the molluscan and annelid crosses cannot be upheld as independent potential synapomorphies of molluscs/sipunculans and echiurans / annelids, respectively.
- The plesiomorphic nature of myoepithelial organization of the body wall musculature is evident in adult annelids, echiurans, and sipunculids.
- The body of an echiuran lacks annelid-type segmentation, but the distinctive free-swimming trochophore larval stages of echiurans and polychaetes are very similar.
echiuroid
- The oxygen consumption of the echiuroid BoneUia viridis has been investigated by means of a continuous-flow polarographic respirometer.
- Echiuroids also move by extending the proboscis, which takes hold of some fixed object, and, then contracting, draws the body forwards.
Origin
Modern Latin (earlier Echiuroidea), from Greek ekhis 'viper' + oura 'tail'.