Molecular phylogeny of large miliolid foraminifera (Soritacea Ehrenberg 1839)

The foraminiferal superfamily Soritacea belongs to the suborder Miliolina a nd is divided in two families, Peneroplidae and Soritidae, the latter one c omprising two subfamilies, Archaiasinae and Soritinae. Phylogenetic relatio nships of 11 genera of soritid foraminifera were investigated by sequencing the complete SSU rDNA gene for 25 specimens. Additionally, partial SSU rDN A sequences were obtained from another 15 specimens of Soritinae. DNA seque nce analysis confirms the monophyly of each family. Caribbean Archaiasinae form a monophyletic clade with Pacific Laevipeneroplis at the base. The gen us Parasorites apppears as a sister taxa to Soritinae. Complex morphologica l features that characterize the genus Marginopora seem to have evolved ind ependently at least twice, as the examined representatives cluster within t wo other soritine genera. Molecular analysis further shows that Sorites orb iculus and Sorites marginalis represent two different morphotypes of one sp ecies. Our data indicate that morphological changes and acquisition of new endosymbiont types in each group played an important role in the adaptation and radiation of Soritacea. (C) 2001 Elsevier Science B.V. All rights rese rved.