Calcareous algae from the Ordovician succession (Thango Formation) of the Spiti Basin, Tethys Himalaya, India

The calcareous algae Dasyporella silurica, Moniliporella multipora and Vermiporella fragilis are reported for the first time from the Middle Ordovician (Dapingian to Darriwilian) Thango Formation of the Spiti Basin of northern India (Pin Valley, Tethys Himalaya). Moniliporella multipora is reported for the first time from the entire Spiti Basin. This algal assemblage is broadly comparable to that of the directly overlying Takche (=Pin) Formation in the Spiti Basin, as well as that reported from the Ordovician succession of the Tarim Basin and from Kazakhstan. The presence of these calcareous algae is of biogeographical and biostratigraphical significance as it indicates a shallow marine depositional environment for the Thango Formation of the Spiti Ba