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1.3 Echiura. 2 Class Clitellata. ... Print/export Download as PDF; Printable version; In other projects Wikidata item; Appearance.
Segmentation in animals typically falls into three types, characteristic of different arthropods, vertebrates, and annelids. Arthropods such as the fruit fly form segments from a field of equivalent cells based on transcription factor gradients. Vertebrates like the zebrafish use oscillating gene expression to define segments known as somites
Download as PDF; Printable version; In other projects ... ("all the arthropods") while the animals with jointed limbs and hardened cuticles should be ... 267 M: 1 to ...
Annelids are members of the protostomes, one of the two major superphyla of bilaterian animals – the other is the deuterostomes, which includes vertebrates. [68] Within the protostomes, annelids used to be grouped with arthropods under the super-group Articulata ("jointed animals"), as segmentation is obvious in most members of both phyla.
Lophotrochozoa (/ l ə ˌ f ɒ t r oʊ k oʊ ˈ z oʊ ə /, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. [2] [3] The clade includes animals like annelids, molluscs, bryozoans, and brachiopods. [4]
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. [4] The term Spiralia is applied to those phyla that exhibit canonical spiral cleavage , a pattern of early development found in most members of the Lophotrochozoa .
The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about 15 000 modern species including the well-known earthworms and leeches The main article for this category is Annelid .
Dunn et al. in 2008 suggested that the tardigrada could be grouped along with the nematodes, leaving Onychophora as the sister group to the arthropods. [12] The non-panarthropod members of Ecdysozoa have been grouped as Cycloneuralia but they are more usually considered paraphyletic in representing the primitive condition from which the ...