Two new species of land planarians (Platyhelminthes, Tricladida, Geoplanidae) from protected areas in the southern extreme of the Paranaense Rainforest, Argentina

Abstract

Here, we describe two new flatworm species of the genera Obama Carbayo et al., 2013 and Notogynaphallia Ogren & Kawakatsu, 1990 (Geoplaninae) found in riverine forests of central-eastern Argentina. Obama maculatentis sp. nov., which is about 50 mm in length, is characterized by black olive pigmentation on the dorsum, with two irregular rows of black spots, and light grey ventral surface. The eyes, with clear halos, extend to the dorsal surface. The foremost features of the copulatory apparatus include dorsal testes anterior to ovaries, extrabulbar prostatic vesicle with forked proximal portion, protrusible penis, male atrium with a large dorsal fold separating it from the female atrium, ovovitelline ducts ascending at the level of the gonopore, common ovovitelline duct dorsal to the distal portion of the female atrium, female canal ventro-anteriorly flexed, and female atrium with narrow lumen. Notogynaphallia fortuita sp. nov., which is about 30 mm in length, is characterized by beige ground pigmentation with tiny darker spots, cephalic region saffron yellow, and ventral surface light grey. The eyes, with small clear halos, extend to the dorsal surface. Regarding the internal anatomy, this new species shows parenchymatic musculature not organized in discrete layers, testes arising near the anterior end of the body, distal sperm ducts traversing the common muscle coat and joining in a short common sperm duct. The areas in which the land planarians were found represent the southernmost latitudes with representatives of the Interior Atlantic Forest (Paranaense Rainforest) biota, hence their biogeographical and conservation significance.