Monothalamea
Taxonomic group of foraminifera
From Wikipedia, the free encyclopedia
Monothalamea is a grouping of foraminiferans, traditionally consisting of all foraminifera with single-chambered tests. Recent work has shown that the grouping is paraphyletic, and as such does not constitute a natural group; nonetheless, the name monothalamea continues to be used by foraminifera workers out of convenience.[4]
| Monothalamea | |
|---|---|
| |
| Image of a deep sea xenophyophore | |
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Sar |
| Clade: | Rhizaria |
| Phylum: | Retaria |
| Subphylum: | Foraminifera |
| Class: | Monothalamea Haeckel, 1862,[1] emend. Pawlowski et al., 2013[2] |
| Orders and subtaxa incertae sedis[3] | |
| |
Classification
"Monothalamea" traditionally contains two groups, neither of which is currently considered to be monophyletic:
- "Allogromiida" traditionally consists of all foraminifera which lack a mineralised test, instead having a test of tectin. Recent work has shown that this grouping is paraphyletic.
- "Astrorhizida" traditionally consists of all foraminifera with single-chambered, agglutinated tests. Recent work has shown that this grouping is polyphyletic, as agglutinated tests have evolved from proteinaceous tests multiple times throughout foraminiferal evolution.[4]
Recent molecular evidence has revealed that the deep-sea xenophyophores are in fact agglutinated, single-chambered foraminifera.[5] Molecular evidence has also revealed that the freshwater protist Reticulomyxa is in fact a naked, testless foraminifera, and as such it has been included with monothalameans in scientific discussion.[4][6]
A 2013 molecular study using small subunit rDNA concluded that known monothalameans made up at least 22 distinct living clades from marine environments with an additional four clades from freshwater eDNA.[4]
