A key to the freshwater triclads (Platyhelminthes, Tricladida) of Herzegovina watercourses

Abstract

The aim of this paper is to describe morphological characteristics of freshwater triclads in Herzegovina and to provide a key for their identification based mainly on their external morphology. Our research is based on the freshwater triclads collected at 26 sites in Herzegovina, including 10 rivers, 6 springs and 1 lake. Triclads were collected by hand and with the bait jar with a lid bearing many small perforations. Specimens were identified immediately after being collected or we transported them to the laboratory in termal containers with ice. The morphological features used for species identification in this key are: body coloration (color of the dorsal and ventral side), the size of the pharynx, the presence of tentacles and their location, number and position of the eyes in respect to each other and the body margin, and the shape of the head. Specimens were fixed using Steinmann's fluid and conserved in 70 % alcohol. Inner morphological feature, shape of a penis, was used in determination of Polycelis tenuis and Polycelis nigra.We collected a total of 11 species, belonging to 8 genera (Polycelis Ehrenberg, 1831, Crenobia Kenk, 1930, Phagocata Leidy, 1847, Planaria Mül-ler, 1776, Dendrocoelum Örsted, 1844, Schmidtea Ball, 1974, Dugesia Girard, 1850, Girardia Ball, 1974) and 3 families.The present study forms a baseline for future studies on the diversity and biogeography of Herzegovinian freshwater triclads. IntroductIonT he order Tricladida comprises the free-living flatworms. Within Tricladida, three infraorders have been recognized: Maricola (marine triclads), Paludicola (freshwater triclads), and Terricola (land triclads) (1), to which a new one, the Cavernicola was further added (2). Study based on molecular properties (3) indicates that the Terricola and Paludicola should be replaced with a clade Continenticola. This new clade comprises the families Planariidae Stimpson, 1857, Dendrocoelidae Hallez, 1892, Kenkiidae Hyman, 1937, Dugesiidae Ball, 1974 and Geoplanidae Stimpson, 1857. We based our research on freshwater triclads belonging to the families Planariidae, Dendrocoelidae and Dugesiidae.Despite some intensive studies (5-9), phylogeny, taxonomy and distribution of this group of organisms are still quite unknown and unexplained. The fauna of freshwater triclads in Bosnia and Herzegovina is not sufficiently explored. The latest surveys were conducted in the 1920s (15). So far no keys for freshwater triclads were published in this region and the aim of this paper is to remedy this. SAmplIng SIteS And methodSAltogether, 26 sites in Herzegovina were sampled, encompassing sites along the courses of rivers Neretva, Buna, Bunica, Bijela, Trebižat, Lištica, Jasenica, Radobolja, Studenčica and Crnašnica but also various habitats (springs and streams) in many of their tributaries (e.g. Crnašnica Vrilo, Crno Oko, Jasle, Arapi Vrilo, Rebrac etc.). Sampling sites, apart from spring Jasle in Masna Luka, belong to the so-called "lower Herzegovina" with an average temperature of 15 °C and an average r...

The invasive alien freshwater flatworm Girardia tigrina (Girard, 1850) (Platyhelminthes, Tricladida) in Western Europe: new insights into its morphology, karyology and reproductive biology

“…The first European record of this alien species was from Germany (Meinken, 1925), after which it was reported from France (De Beauchamp, 1946;Gourbault, 1969;Vila et al, 2004), Switzerland (Dahm, 1955), Great-Britain (Reynoldson, 1956), The Netherlands (Den Hartog, 1959), Luxembourg (Hoffmann, 1964), Iberian Peninsula and the Balearic Islands, Azores (Baguña et al, 1980;Ribas et al, 1989;Malhão et al, 2007;Vila-Farré et al, 2011 and references therein), and also from the Balkan peninsula from countries such as Romania (An der Lan, 1962;Babalean, 2018) and Herzegovina (Knezović et al, 2015). In the Italian peninsula, since the 1960s populations of G. tigrina were recorded from many localities (Stagni & Grasso, 1965;Stella & Margaritora, 1966;Benazzi, 1981Benazzi, , 1993Stocchino et al, 2013a).…”

Planarians, a Neglected Component of Biodiversity in Groundwaters

“…Commonly referred to as "flatworms" because of their dorso-ventral flattening, freshwater planarians are found mainly in surface waters [19,20], however an unexpected diversity of planarians occurs also in groundwaters [21,22]. Nearly 200 species of planarians have been recorded in groundwater environments [23].…”