Fabricational morphology of oblique ribs in bivalves

摘要: The formation of oblique ribs bivalve shells usually has been attributed to processes reaction-diffusion morphogens from cell at the mantle margin or neural activation and lateral inhibition in mantle. In particular, such appear with high rates diffusion. Nevertheless, theoretical models fail explain either partially wholly some varieties ribs. After surveying modes shell by associated fabricational defects, I have determined that is able develop an elaborate behavior order displace rib a particular direction during growth. is, therefore, not only shell-secreting organ, but also main morphogenetic unit. there are two strategies. forms strict contact guidance (SCG) project far enough beyond margins so as feel already formed reliefs align new growth increments appropriate directions. always strongly reflected. bivalves reduced plus constant shift (RCG), acute information about available reduced. During construction extrudes slightly edge then pushes laterally muscular action; this way, increment displaced on small scale. contact-guidance model supported homogeneous structure From standpoint, related commarginal ones both differ completely other ribbing patterns bivalves. J. Morphol. 254:195–209, 2002. © 2002 Wiley-Liss, Inc.