An endostyle is a longitudinal cilia ted groove on the ventral wall of the pharynx which produces mucus to gather food particles. It is found in urochordate s and cephalochordate s, and in the larvae of lamprey s. It aids in transporting food to the esophagus . It is also called the hypopharyngeal groove. The endostyle in larval lampreys ammocetes Metamorphosis biology metamorphoses into the thyroid gland in adults, and is regarded as being Homology biology homologous to the thyroid gland in vertebrate s. However, Dumont, et al. question whether the endostyle in ammocetes is homologous with that of the urochordates and cephalochordates. Since the endostyle is found in the three branches of chordate s, it is presumed to have arisen in the common ancestor of these Taxon taxa , along with a shift to internal feeding for extracting suspended food from the water. References reflist No footnotes date September 2009 Marine, David. 1913. http jem.rupress.org content 17 4 379.abstract The Metamorphosis of the Endostyle Thyroid Gland of Ammocoetes branchialis Larval Land Locked Petromyzon marinus Jordan or Petromyzon dorsatus Wilder , The Journal of Experimental Medicine , 17 379 395. Ogasawara, M. and Satoh, N. 1998. http www.biolbull.org cgi content abstract 195 1 60 Isolation and Characterization of Endostyle Specific Genes in the Ascidian Ciona intestinalis , The Biological Bulletin , 195 60 69. Dumont, J. E., Corvilain, B., and Maenhaut, C. 2002. http www.thyroidmanager.org Chapter1 chapter01.pdf Chapter 1 The Phylogeny, Ontogeny, Anatomy, and Metabolic Regulation of the Thyroid , Thyroid Disease Manager . Category Chordate anatomy chordate stub cs Endostyl de Endostyl es Endostilo pl Endostyl pt End stilo ... more details
Taxobox name Didazoon fossil range Early Cambrian image Didazoon haoae.jpg image caption Didazoon haoae regnum Animal ia phylum Vetulicolia phylum authority Shu, et al. 2001 ordo Vetulicolida ordo authority Chen & Zhou 1997 familia Didazoonidae familia authority Shu & Han 2001 genus Didazoon genus authority Shu & Han 2001 species Didazoon haoae species authority Shu & Han 2001 The genus Didazoon was erected by Shu, et al. based on fossils found in the Qiongzhusi Chiungchussu Formation, Yu anshan Member Eoredlichia zone , Early Cambrian Lower Cambrian , in the Dabanqiao area Kunming , about 60 km northwest of Chengjiang , China . It currently consists of the single species Didazoon haoae . The fossils show that the body of the animal was covered in a thin, flexible cuticle . The anterior part of the body was divided into six Segment biology segments , with fairly broad membranes separating the segments, and the Posterior anatomy posterior part of the body was divided into seven segments. The constriction between the anterior and posterior parts of the animal shows creasing, and the authors hypothesize that it was quite flexible. The fossils are interpreted as showing a large anterior opening, presumably a mouth, a spacious anterior cavity, an alimentary canal , possibly voluminous in the anterior section, and a narrow intestine in the posterior section, straight or coiled in one specimen . There are five structures on each side of the anterior portion that the authors interpret as gills . Narrow strands towards the Anatomical terms of location Directional terms lateral margins, sometimes branched, may represent vascular tissue . The authors also identify a dark strand on the lower interior surface of the anterior section, which they speculate is an endostyle . See also Maotianshan shales References Shu, D. G., Conway Morris, S., Han, J., Chen, L., Zhang, X. L., Zhang, Z. F., Liu, H. Q., Li, Y., and Liu, J. N. 2001. Primitive Deuterostomes from the Chengjiang Lag ... more details
Taxobox name Xidazoon fossil range Lower Cambrian image Xidazoon stephanus e.jpg image width 240px image caption Artist s concept of Xidazoon stephanus regnum Animal ia phylum Vetulicolia phylum authority Shu, et al. 2001 ordo Vetulicolida ordo authority Chen & Zhou 1997 familia Didazoonidae familia authority Shu & Han 2001 genus Xidazoon genus authority Shu, Conway Morris & Zhang 1999 species X. stephanus binomial Xidazoon stephanus The genus Xidazoon was erected by Shu, et al. 1999 based on fossil s found in the Qiongzhusi Chiungchussu Formation, Yu anshan Member Eoredlichia zone , Lower Cambrian, Haikou, Kunming , about 50 km west of Chengjiang , China . It currently consists of the single species Xidazoon stephanus . The fossils show that the body of the animal was divided into two parts. The anterior part of the body is moderately inflated, with a prominent mouth circlet. It has faint Transverse plane transverse divisions towards the front, but is otherwise smooth. The mouth circlet consists of about 30 plates divided into inner and outer regions. The anterior section has five structures on each side, which are interpreted as gills . A dark region running close to the ventral and posterior margins is interpreted as an endostyle . The condition of the anterior portion of the fossils suggests that it was thin walled, i.e., that the anterior portion was largely hollow. The Posterior anatomy posterior part of the body tapers towards front and back diamond shaped , and is divided into seven Segment biology segment s covered in cuticle with three less well defined segments at the anterior end. ref Shu Degan. 2005 On The Phylum Vetulicolia. Chinese Science Bulletin. ref There are short spines at the posterior tip. The authors describe an alimentary canal with terminal openings and a rectum with what might be dilator muscles. Based on a comparison of the incomplete damaged holotype with the incomplete damaged holotype of Pomatrum ventralis , researchers Aldridge, ... more details
the stigmata. A long ciliated groove, or endostyle , runs along one side of the pharynx, and a projecting ridge along the other. The endostyle may be Homology biology homologous with the thyroid ... IZ Digestive system The pharynx forms the first part of the digestive system. The endostyle produces ..., or close to the stomach. Each end opens into a single vessel, one running to the endostyle ... more details
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