First Fossil Faorina (Echinoidea: Spatangoida) from the Bhuban Formation (Miocene), Northeastern India

Heart urchins of the genus Faorina are now endemic to the Indo-West Pacific, but their fossils were previously known from the Miocene of Mediterranean, indicating a wider geographic distribution in the past. Here we describe Faorina mizoramensis sp. nov. from the Lower to Middle Miocene Bhuban Formation (Surma Group) in northeastern India, identified by their meridoplacous plating in interambulacrum 1 adorally. These fossils demonstrate that the distribution of Faorina had reached the eastern Indian Ocean (or Ceno-Tethys) by the Early to Middle Miocene. This study shows that Faorina likely expanded widely, extending into the Mediterranean during the Miocene. Following the closure of the Tethyan Seaway, they experienced local extinction. Today, they are restricted to Taiwan, southern China, Vietnam, Australia, Sulu Sea, Burma, and the Andaman Islands. We therefore hypothesize that Faorina may have originated in the Mediterranean, with the Indo-West Pacific later becoming a refugium for this genus and some of the tropical to subtropical Ceno-Tethyan echinoid faunas.