The taxonomy, ultrastructure and biogeography of Eunotia camelus and infraspecific taxa, with a focus on the taxa described by Frenguelli from the Esteros del Iber (Argentina)

Eunotia is a large, taxonomically complex genus globally distributed, with many endem-ics described. In tropical regions of South America many Eunotia taxa have been reported and de-scribed. In 1933 Frenguelli reported 55 different taxa of this genus from the Iber. wetland with a high rate of endemism. One of the species reported by this author with the highest number of in-fraspecific taxa was Eunotia camelus, originally described from Cayenne and whose type material was later documented by Reichardt, allowing a better understanding of this species. E. camelus has been reported worldwide in its distribution and there has been great confusion about the identity and distribution of this supposedly cosmopolitan species. The purpose of the present study is to detail with LM and SEM observations, taxa of E. camelus and its close allies reported in the Iber. wetland ecosystem by Frenguelli, and to consider the biogeographic distribution of this species complex. We analyzed samples from both recent and historical collections from different geograph-ic areas: Esteros del Iber. (Argentina), Banka Island (Indonesia) and Kolhapur, Western Ghats (India). As a result we conclude that the E. camelus complex originally reported from the Iber. in fact contains four different species: Eunotia camelus, Eunotia juga comb. nov. stat. nov., Eunotia ectorii nom. nov. stat. nov., and Eunotia carambolensis nov. spec. Furthermore, these taxa are not conspecific with those described from Indonesia and India. Our observations show that E. camelus is not a cosmopolitan or pantropical species, but it and its close allies rather comprise a group of morphologically similar species, each with a much more limited distribution.