DNA and Morphology Unite Two Species and 10 Million Year Old Fossils
Figure 2
Potential phylogenetic positions of Alcithoe knoxi.
Morphological ambiguity results in a range of phylogenetic hypotheses for the placement of A. knoxi, ranging from (A) A. knoxi representing a distinct lineage (genus Teremelon) sister to the Alcithoe lineage, to (B) A. knoxi is a form of A. wilsonae nested within the modern diversity of Alcithoe. The node that would be calibrated at approximately 10my based on the A. knoxi fossils is shown (arrows). Calibration (A) would set a maximum limit of the origin of the modern Alcithoe at no earlier then 10mya, whereas (B) would allow the diversification of the extant Alcithoe to have occurred earlier.