Skip to main content

Free Content Larval biology of early Cambrian molluscs: The implications of small body size

Download Article:
 Download
(PDF 764.9736328125 kb)
 
Current theory suggests that the ancestral larval condition in molluscs was planktic and planktotrophic. Using Recent marine gastropods with similar shell morphologies and Recent molluscan life-history data, we constructed a model that estimates Cambrian univalve fecundities over a range of shell lengths, egg sizes, and body plans. Using the correlation between fecundity and mode of larval development present in Recent marine benthic invertebrates, we infer mode of larval development for Cambrian species. Because of their minute body size, the potential fecundities of most Early Cambrian taxa are substantially below the fecundities correlated with planktic development in Recent gastropods. By the Late Cambrian and Early Ordovician molluscan body size sufficiently increased to produce fecundities similar to those correlated with planktic development in Recent taxa. The life-history patterns present in extant molluscan groups with Cambrian originations also strongly suggest external fertilization, relatively large eggs and lecithotrophic development as the ancestral condition. We propose that the evolution of larval development in Cambrian molluscs proceeded from nonplanktic lecithotrophic development to planktic lecithotrophic development and that planktotrophic larvae are secondarily derived.

27 References.

No Supplementary Data.
No Data/Media
No Metrics

Document Type: Research Article

Publication date: 1986-09-01

More about this publication?
  • The Bulletin of Marine Science is dedicated to the dissemination of high quality research from the world's oceans. All aspects of marine science are treated by the Bulletin of Marine Science, including papers in marine biology, biological oceanography, fisheries, marine affairs, applied marine physics, marine geology and geophysics, marine and atmospheric chemistry, and meteorology and physical oceanography.
  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • Terms & Conditions
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more