Equisetum thermale is an extinct horsetail species in the family Equisetaceae described from a group of whole plant fossils including rhizomes, stems, and leaves.

The formations is the result of Jurassic age fault generated valleys filled by lacustrian infilling and hydrothermal activity represented by epithermal deposits.

[1] The species was described from a part and counterpart pair of specimens, the holotype, number "MPM-PB 2029" which is currently preserved in the paleobotanical collections housed at the Museo Provincial Padre Jesús Molina, Río Gallegos, Santa Cruz, Argentina.

[1] The specimens were studied by a group of four Welsh and Argentinian paleobotanists led by Alan Channing of the School of Earth and Ocean Sciences, Cardiff University, Wales.

[1] The etymology of the chosen specific name thermale is in recognition of both the geology of the type location and as a reference to the original habitat of a hot spring.