Land flatworm (Platyhelminthes, Tricladida) inventory in a remnant of Subtropical Deciduous Forest in Southern Brazil

Abstract

Land triclads are top-predators in their microhabitats, feeding on other soil invertebrates. The species richness of triclads may indicate the diversity of other faunal groups. The community composition of land flatworms of areas of Deciduous Forest, which occupies a quarter of the vegetal cover of the state, is poorly known. The present study inventoried land planarians of the largest remnant of this type of forest in the State of Rio Grande do Sul, the Turvo State Park (SP-Turvo) and compared their communities with those of other localities of the state with inventories of land flatworms. We inventoried 26 species, two of them belonging to the subfamilies Rhynchodeminae and Bipaliinae, and 24 to the subfamily Geoplaninae. Besides the genera Rhynchodemus Leidy 1851 and Bipalium Stimpson, 1857, the following Geoplaninae genera were recorded: Geoplana Stimpson 1857, Choeradoplana Graff 1896, Pasipha Ogren & Kawakatsu 1990 and Notogynaphallia Ogren & Kawakatsu 1990, as well as the collective group Pseudogeoplana Ogren & Kawakatsu, 1990. The highest species richness was registered for the genus Geoplana (10), followed by the genus Pasipha (4). Geoplana rubidolineata Baptista & Leal-Zanchet, 2005 was previously only known from its type-locality, located in the northeast of the state. Bipalium kewense Moseley, 1878 which shows a cosmopolitan distribution was observed in a man-disturbed area, not being registered in forest areas. We employed an NMDS ordination to compare land planarian communities of the Turvo State Park to those of other types of forest of the state. The analysis indicated that land planarian communities of the Turvo State Park and those of other areas with Deciduous, Semideciduous and Dense Ombrophilous Forests differ from those of Mixed Ombrophilous Forests of the region. The high observed species richness in the Turvo State Park reinforces its important contribution for the conservation of the regional diversity.