In today's world, Scalidophora has become a recurring topic of indisputable relevance. Whether due to its impact on society, politics or people's daily lives, Scalidophora has acquired significant importance today. Its influence is not limited to a specific area, but covers various aspects ranging from technology to culture. With the advance of globalization, Scalidophora has become a common point of interest in all corners of the world, generating debates, reflections and actions that seek to understand and address its scope and impact. In this article, we will thoroughly explore the impact of Scalidophora and its implications on different aspects of modern life.
Scalidophora | |
---|---|
Ottoia prolifica from the Walcott Quarry of the Burgess Shale (Middle Cambrian) near Field, British Columbia, Canada. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Subkingdom: | Eumetazoa |
Clade: | ParaHoxozoa |
Clade: | Bilateria |
Clade: | Nephrozoa |
(unranked): | Protostomia |
Superphylum: | Ecdysozoa |
Clade: | Scalidophora Lemburg, 1995 |
Phyla | |
| |
Synonyms | |
Cephalorhyncha, Priapozoa |
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera. The three phyla have four characters in common — chitinous cuticle that is moulted, rings of scalids on the introvert, flosculi, and two rings of introvert retracts. The introvert and abdomen are separated by a distinct neck region in all groups, but in adult macroscopic priapulids it becomes rudimentary in Priapulus and is completely absent in Halicryptus. However, the monophyly of the Scalidophora was not supported by two molecular studies, where the position of the Loricifera was uncertain or as sister to the Panarthropoda. Both studies supported a reduced Scalidophora comprising the Kinorhyncha and Priapulida as sister phyla. Their closest relatives are the Panarthropoda, Nematoda and Nematomorpha; thus, they are placed in the group Ecdysozoa.
The two species in the genus Markuelia, known from fossilized embryos from the middle Cambrian, are thought to be stem Scalidophorans.
The group has also been considered a single group, Cephalorhyncha, with three classes.
The group is named after the spines (scalids) covering the introvert (head that can be retracted into the trunk).