“…However, one species of Mellita, M. grantii Mortensen, 1948, proved problematic for Mayr (1954) and he chose to ignore it in his analysis, stating that Mortensen (1948) had described M. grantii based on a single specimen from the midst of the range of M. longifissa Michelin, 1858. Mayr's (1954 model of allopatric speciation in echinoids has been supported by molecular phylogenies of regular sea urchins (Lessios et al, 1999(Lessios et al, , 2001(Lessios et al, , 2003(Lessios et al, , 2012McCartney et al, 2000;Zigler and Lessios, 2004;Palumbi and Lessios, 2005), but to-date this hypothesis has not been tested with a molecular phylogeny of a sand dollar genus.…”