Cephalochordata

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Cephalochordata

[¦sef·ə·lō‚kȯr′däd·ə]
(vertebrate zoology)
A subphylum of the Chordata comprising the lancelets, including Branchiostoma.
References in periodicals archive ?
Steinke for maintaining the cephalochordates in the laboratory and to Malcolm R.
The cephalochordate genera Branchiostoma and Asymmetron diverged during the Mesozoic Era.
In addition, cephalochordate larvae have several quantifiable phenotypic characters (like size of the preoral ciliated pit and angle of deflection of the larval gill slits and anus from the ventral midline).
However, if basal cephalochordates were Asymmetron-like in lacking Hatschek's left diverticulum, the evolution of that structure would be a derived peculiarity of the genus Branchiostoma and could not be homologized with any feature of other chordates.
The present discussion calls attention to the importance of settling the current disagreement about the course of evolution within the cephalochordates.
Unlike vertebrates, the tunicates and cephalochordates never convert their notochord into a vertebral column or backbone.
These data clearly demonstrate that Hb capable of reversible oxygen binding is expressed in two species of cephalochordates, thus expanding the known range of expression among chordates to include nonvertebrate chordates.
The existence of intracellular Hb dimers in cephalochordates is not unexpected because their nearest vertebrate relatives (the lamprey) also produce Hb dimers (12,13,14).
In future studies, we should use these probes to isolate endostyle-specific genes from cephalochordates, cyclostomes, and hemichordates.