A new and threatened species of internally inseminating seasonal killifish of Campellolebias (Cyprinodontiformes: Rivulidae) endemic to a continental island in the Atlantic Forest, Southern Brazil

Abstract

Campellolebias comprises small internally inseminating seasonal fishes that inhabit temporary pools in tropical and subtropical areas of the Atlantic Forest. It currently encompasses four species. Integrative taxonomy was used here to investigate a possible new species found in the island of Florianópolis, southern Brazil. The examined material confirm that it pertains to a new species. Furthermore, minimum genetic distances found between this and other species of Campellolebias regarding mitochondrial markers were higher than 3 %. This new species is distinguished from all other species of Campellolebias by the combination of a series of character states, including the color pattern in both sexes, pelvic-fin bases separated by an interspace, pelvic-fin tips reaching base of the 1st anal-fin ray in males and the urogenital papilla in females, by possessing 1–2+24-29 infraorbital neuromasts, 2–4 otic neuromasts, and by the anal-fin origin being positioned at a vertical between the base of the 4th and 6th dorsal-fin ray in females. Campellolebias insularis, new species, occurs exclusively in small temporary wetlands in areas under strong threat due to real estate development, in the island of Florianópolis. Due to the advanced stage of habitat loss and degradation, its restricted distribution area, and the reduced populations sizes, the species is considered Critically Endangered. Additionally, comments are provided on the putative relationships of the new species, its conservation status, and an identification key for the species of Campellolebias.