Abstract
The radiolarian subfamily Artiscinae in deep-sea sediments of the equatorial Pacific consists of both an ancestral lineage that has persisted from the Early Miocene to the Recent and a descendant lineage that originated, probably by allopatric speciation, in the Middle Miocene and became extinct at the end of the Miocene. Measurements of shell dimensions were made on samples of both lineages throughout their stratigraphic ranges. For almost all of the measured dimensions, morphologic rates of change increased in the ancestral lineage following the establishment of sympatry with the descendant lineage. Rates of change were consistently higher in the descendant lineage than in the ancestral lineage during sympatry. Differential rates of phyletic change exhibited by the 2 lineages resulted in significant divergence between them, which may be interpreted as possible character displacement at the
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
