Molecular Phylogeny and Morphology of Leannia veloxifera n. gen. et sp Unveils a New Lineage of Monothalamous Foraminifera

摘要

Monothalamous (single-chambered) foraminifera have long been considered as the poor cousins of multichambered species, which calcareous and agglutinated tests dominate in the fossil record. This view is currently changing with environmental DNA surveys showing that the monothalamids may be as diverse as hard-shelled foraminifera. Yet, the majority of numerous molecular lineages revealed by eDNA studies remain anonymous. Here, we describe a new monothalamous species and genus isolated from the sample of sea grass collected in Gulf of Eilat (Red Sea). This new species, named Leannia veloxifera, is characterized by a tiny ovoid theca (about 50-100m) composed of thin organic wall, with two opposite apertures. The examined individuals are multinucleated and show very active reticulopodial movement. Phylogenetic analyses of SSU rDNA, actin, and beta-tubulin (ss-tubulin) show that the species represents a novel lineage branching separately from other monothalamous foraminifera. Interestingly, the SSU rDNA sequence of the new species is very similar to an environmental foraminiferal sequence from Bahamas, suggesting that the novel lineage may represent a group of shallow-water tropical allogromiids, poorly studied until now.