Under threat: Two new troglobitic species of Girardia (Platyhelminthes: Tricladida) from sandstone and limestone caves in Brazil

Abstract

Abstract The diversity of freshwater triclads of the suborder Continenticola in the Neotropical region is poorly known, with few studies in South America. In this work, we describe two new cave-dwelling species of Girardia: G.\xa0corumbataiensis sp. nov. is described from a single sandstone cave located in an area covered by semi-deciduous vegetation, southeastern Brazil; G.\xa0nobresis sp. nov. is described from a single flooded limestone cave located in an area of Cerrado vegetation, central-western Brazil. Specimens of G.\xa0corumbataiensis sp. nov. have a slight pigmented dorsal surface with highly triangular head and two eyes, whereas specimens of G.\xa0nobresis sp. nov. lack body pigmentation and eyes and have pointed auricles. Girardia corumbataiensis sp. nov. shows a pear-shaped bulbar cavity with forked portions turned dorsally and a slightly bent bursal canal. Girardia nobresis sp. nov. has an ample bulbar cavity with numerous folds and an angled bursal canal. The two new species are categorized as troglobites and easily recognized by a unique combination of characters of their external morphology and copulatory apparatus. G.\xa0corumbataiensis sp. nov. occurs in a cave inserted in a protected area, but no effective action for preservation has been provided. This species is abundant in a single stream crossing the cave, which is subject to intensive visitation and control of bat populations, besides Eucalyptus plantations nearby. The type-locality of G.\xa0nobresis sp. nov., a single flooded cave near a municipal road, has no legal protection. There are impacts, such as intensive visitation for fishing and deforestation in its surroundings.