![]() In deuterostomes, the early divisions occur parallel or perpendicular to the polar axis. In both deuterostomes and protostomes, a zygote first develops into a hollow ball of cells, called a blastula. The phylum Chaetognatha (arrow worms) may belong here, but molecular studies have placed them in the protostomes more often.Įxtinct deuterostome groups may include the phylum Vetulicolia.Įchinodermata and Hemichordata form the clade Ambulacraria.įile:Protovsdeuterostomes.svg Notable characteristics However, Superphylum Deuterostomia was redefined in 1995 based on DNA molecular sequence analyses when the lophophorates were removed from it and combined with other protostome animals to form superphylum Lophotrochozoa. Previously, Deuterostomia also included the phyla Brachiopoda, Bryozoa, Chaetognatha, and Phoronida based on embryological characteristics. Hemichordata ( acorn worms and graptolites).Echinodermata ( starfish, sea urchins, sea cucumbers, etc.).There are three major clades of deuterostomes: )ĭeuterostomes are also known as enterocoelomates because their coelom develops through enterocoely. (There are some occurrences of deuterostomy among Protostomes. It is a sister clade of Protostomia, with which it forms the Nephrozoa clade.ĭeuterostomia is a subtaxon of the Bilateria branch of the subkingdom Eumetazoa, within Animalia, and are distinguished from protostomes by their deuterostomic embryonic development in deuterostomes, the first opening (the blastopore) becomes the anus, while in protostomes, it becomes the mouth. Deuterostomes (taxonomic term: Deuterostomia meaning "second mouth" in Greek) are any members of a superphylum of animals. ![]()
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