Knowra Lophotrochozoa Lophotrochozoa Lophotrochozoa is a major clade of protostome animals that includes mollusks, annelids, brachiopods, and several other phyla. Its members are united primarily by molecular evidence rather than one shared visible body plan.
Protostomia : Protostomia is a major clade of bilaterian animals that includes lophotrochozoans and ecdysozoans. Lophotrochozoa is one of the two major branches traditionally recognized within this protostome grouping.
Spiral cleavage : Spiral cleavage is a pattern of early embryonic cell division in which successive cell tiers are offset. It characterizes development in many lophotrochozoans, although exceptions are common.
Mollusca : Mollusca is an animal phylum that includes snails, clams, octopuses, and their relatives. It is one of the most diverse and familiar lophotrochozoan phyla.
Ecdysozoa : Ecdysozoa is a protostome clade whose members grow by shedding an external cuticle. It is the other major protostome radiation commonly contrasted with Lophotrochozoa.
Bilateria : Bilateria is the animal clade whose members typically develop bilateral symmetry and three primary germ layers. Lophotrochozoans belong to this broad branch of animals.
Hox genes : Hox genes are conserved regulatory genes that help specify positional identity along an animal embryo's body axis. Comparisons of these genes contribute to studies of body-plan evolution among lophotrochozoans.
Annelida : Annelida is an animal phylum of segmented worms, including earthworms, leeches, and polychaetes. Its segmented worms exemplify one major body plan within the clade.
Deuterostomia : Deuterostomia is a major bilaterian clade that includes chordates, echinoderms, and hemichordates. Its members belong to a separate major branch of Bilateria, not to Lophotrochozoa.
Trochophore : A trochophore is a usually free-swimming larva with bands of cilia, found in several marine invertebrate groups. This larval form occurs in many annelids and mollusks, though not across the whole clade.
Phylogenomics : Phylogenomics infers evolutionary relationships by analyzing genome-scale molecular data. Genome-wide comparisons established Lophotrochozoa as a clade despite the absence of a single universal anatomical marker.
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