![]() ![]() Some scientists believe that the phyla Platyhelminthes and Rotifera within this group should actually belong to their own group of protostomes termed Platyzoa.This discovery allowed for the distinction of the protostome clade: the lophotrochozoans.Extensive molecular analysis using rRNA data found these animals to be protostomes, more closely related to annelids and mollusks.Molecular Analyses and Modern Phylogenetic Trees.In protostomes, part of the mesoderm separates to form the coelom in a process called schizocoely.Unlike protostomes, deuterostomes undergo indeterminate cleavage: cells remain undifferentiated until a later developmental stage.Protostomes also undergo determinate cleavage: the developmental fate of each embryonic cell is pre-determined." The protostomes include arthropods, mollusks, and annelids. The word protostome comes from the Greek word meaning "mouth first.These two groups are separated based on which opening of the digestive cavity develops first: mouth ( protostomes) or anus (deuterostomes). ![]() Animal Characterization Based on Features of Embryological Development.This layer multiplies into a band which then splits internally to form the coelom this protostomic coelom is termed schizocoelom.Animals belonging to superphylum Lophotrochozoa are protostomes: the blastopore (or the point of involution of the ectoderm or outer germ layer) becomes the mouth opening to the alimentary canal.The Lophotrochozoa are protostomes possessing a blastopore, an early form of a mouth they include the trochozoans and the lophophorata.Examples of protostome in the following topics: ![]()
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