Publication Date:
1991-01-18
Description:
Two vertebrates from the Colorado Formation are known to have acellular bone and dentine, tissues found in heterostracan fishes and proposed as the primitive exoskeleton. High-resolution optical microscopy and scanning electron microscopy indicate that a third vertebrate is represented by a quite distinct exoskeleton of denticles, with many cell and cell process spaces throughout, tissue that resembles that of osteostracans more than heterostracans. Cellular bone coexists with cellular dentine in this Ordovician vertebrate, demonstrating that these skeletal tissues are as old as acellular bone. Both are proposed to come from neural crest because denticles are considered homologous with teeth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smith, M M -- New York, N.Y. -- Science. 1991 Jan 18;251(4991):301-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17733288" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
