Staurogyne repens (family Acanthaceae), informally known as creeping staurogyne, is popular for aquascaping, the aesthetic arrangement of plants, rocks and driftwood in an aquarium. This aquatic plant species, described by Nees in Flora Brasiliensis in 1847, is native to Brazil and Guyana, with records from the states of Amazonas, Mato Grosso and Pará in Brazil. Despite being widely cultivated and commercialized, S. repens is underrepresented in herbaria, with only c. 10 specimens including duplicates, the most recent collected in 1907, in Pará.
Brazil's Official National List of Threatened Flora Species categorizes seven of 28 native species of Staurogyne as Vulnerable or Endangered but S. repens is not included and has not yet been assessed on the IUCN Red List. In the latest revision of Staurogyne, Braz & Monteiro (2017, Phytotaxa, 296, 1–40) argued that the lack of recent collections of S. repens indicates it is either rare or extinct in the wild. The abundance of clones of S. repens available commercially suggested to us that this species could fall into Schrödinger's cat extinction paradox (Roberts & Fisher, 2020, Oryx, 54, 143–144), being considered simultaneously both extant and extinct, with lack of knowledge of occurrence in the wild hindering conservation of the species.
In August 2021, however, during an expedition to the Parque Nacional da Chapada das Mesas in the Cerrado of Maranhão, Brazil, we collected two small specimens of Staurogyne growing on rocky banks of the Farinha River. Concurrently, photographs of a similar plant on rocky banks of the Teles Pires river in Mato Grosso were posted by Milton Cordova Neyra on DetWeb, a Facebook group for Brazilian taxonomists and plant enthusiasts. Following examination of the specimens and photographs, we have been able to confirm they are S. repens. These are the first records of this species in the wild for 115 years and expand its known distribution to the Brazilian Cerrado. We will monitor known populations and aim to provide a Red List assessment for S. repens.
We thank FAPEMA (PDCTR-00123/20) and CNPq (301691/2021-5) for financial support, and Lucas Marinho for helpful insights. Our collections were the minimum required for validating the occurrence of S. repens and were made with permission of ICMBio (number 77388-1).
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