Telonemia is a
clade of protists that branch independently from other eukaryotic
supergroups groups as their own 'micro-kingdom'. Early molecular analyses of Telonemia placed them as an independent branch within the
SAR supergroup, a diverse clade of eukaryotes that contain
Rhizaria,
Alveolata and
Stramenopila. Other analyses proposed a close relationship with
centrohelids,
katablepharids,
cryptomonads and
haptophytes. At this time, they were suggested to have
evolutionary significance in being a possible transitional form between ecologically important
heterotrophic and
photosynthetic species among chromalveolates. The present phylogenetic analyses place them as sister to the SAR supergroup in a clade commonly known as
TSAR, which is widely accepted by the scientific community. As the
sister clade to SAR, Telonemia has a key position in the tree of eukaryotic life. They are morphologically complex organisms that combine characteristics of different SAR lineages. The main trait uniting each SAR lineage has been described in at least one genus of Telonemia: tripartite
mastigonemes in the
flagella, typical of
stramenopiles and described in
Lateronema;
cortical alveoli underneath the
plasma membrane, typical of
alveolates and described in
Lateronema; and fine
pseudopodia (
filopodia), typical of
rhizarians and described in
Telonema. Moreover,
Arpakorses presents a kinetid structure similar to that seen in Rhizaria, and
Telonema subtile presents microtubules in a formation superficially resembling the apical complex of
apicomplexans. All telonemid genera possess a highly intricate multi-layered
cytoskeleton, whose complexity is not found in any other eukaryote. This finding may indicate that telonemids have retained an ancestral cytoskeleton organization that has been lost in other eukaryotes. ==Notes==