Deuterostomes (from Greek: lit. 'mouth second') are bilaterian animals of the superphylum Deuterostomia (/ˌdjuːtərəˈstoʊmi.ə/), typically characterized...

lineages, but are not part of the formal definition: All chordates are deuterostomes. This means that, during embryonic development, the anus forms before...

become its digestive tube (the archenteron). In the sister-clade, the deuterostomes (lit. 'second-mouth'), the original dent becomes the anus while the...

as arthropods, molluscs, flatworms, annelids and nematodes; and the deuterostomes, which include echinoderms, hemichordates and chordates, the latter...

consists of triploblastic, eucoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They...

ago in the beginning of the Cambrian period. Initially proposed as a deuterostome, which would have made it the oldest known species of this superphylum...

bilaterian animals into two natural groupings: the protostomes and deuterostomes. In animals at least as complex as an earthworm, a dent forms in one...

Pharyngeal slits are filter-feeding organs found among deuterostomes. Pharyngeal slits are repeated openings that appear along the pharynx caudal to the...

shown by the foot pads. In 2017, a description of a new species of basal deuterostome called Saccorhytus was published. This animal appears to have seta in...

typical of deuterostomes. Hence forming the mouth via a deuterostome-like process does not imply that brachiopods are affiliated with deuterostomes. Nielsen...

the mechanism for creating segments is shared between vertebrates (deuterostomes) and arthropods (protostomes). The first evidence of bilateria in the...

happened at least twice, following different paths in protostomes and deuterostomes. This accompanied or facilitated other important evolutionary developments:...

have been traditionally, but erroneously, classed as deuterostomes by embryologists due to deuterostome-like features in the embryo. Lynn Margulis and K....

stem- and crown-group arthropods, stem-group vertebrates, and early deuterostomes (a group which as a whole includes the vertebrates, other invertebrate...

criterion used to classify bilaterian animals into protostomes and deuterostomes. In the first multicellular animals, there was probably no mouth or...

recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. Immune organs vary by type of fish. The jawless...

its own phylum, Xenoturbellida, as a deuterostome clade and sister group to the Ambulacraria. The deuterostome affiliations were then recovered by studies...

phyla Mollusca, Annelida, and Arthropoda. Deuterostomes usually exhibit enterocoely; however, some deuterostomes like enteropneusts can exhibit schizocoely...

cephalochordate, a stem-chordate, a hemichordate, a stem-vertebrate, a stem-deuterostome, an ambulacrarian, a bilaterian of uncertain placement, as a protostome...

morphological features placed lophophorates among or as a sister group to the deuterostomes, a super-phylum which includes chordates and echinoderms. While a minority...

Bilateria/Triploblast Bilateria: Xenacoelomorpha, Nephrozoa Nephrozoa: Protostomes, Deuterostomes Phylum Proarticulata † Disputed if this is in or out of Bilateria and...

Yanjiahella biscarpa is an extinct species of Early Cambrian deuterostome which may represent the earliest stem group echinoderm. This species is known...

development, into two groups (superphyla) called protostomes and deuterostomes. Deuterostomes include vertebrates as well as echinoderms, hemichordates (mainly...

and Rhombozoa) when it was discovered the Orthonectida are probably deuterostomes and the Rhombozoa protostomes. This changeability of phyla has led some...

model system is the gastruloid. The distinction between protostomes and deuterostomes is based on the direction in which the mouth (stoma) develops in relation...

embryological development of deuterostomes in which the coelom forms. This type of coelom formation occurs in deuterostome animals, which for this reason...

separated around 533 million years ago. The Ambulacraria are part of the deuterostomes, a clade that also includes the many Chordata, and the few extinct species...

layer and the visceral layer is known as the coelom or body cavity. In deuterostomes, the coelom forms by enterocoely. The archenteron wall produces buds...

(dragonflies and damselflies), Hemiptera (true bugs) nymph wriggler]] Deuterostomes dipleurula (hypothetical larva) Echinodermata bipinnaria, vitellaria...

sea urchin are the sea cucumbers (Holothuroidea), which like them are deuterostomes, a clade that includes the chordates. (Sand dollars are a separate order...