Theama mediterranea sp. nov. (Platyhelminthes, Polycladida), the first interstitial polyclad from the Mediterranean

Abstract

A new species of mesopsammic polyclad, Theama mediterranea sp. nov., from lower intertidal habitats of the Mediterranean Sea, is described. The species differs from congeneres found in the tropical Pacific and the Atlantic coast of South America, in terms of size, structure of the male copulatory organ and number of eyes. T. mediterranea sp. nov. has a short pelagic juvenile phase, while adults are strictly interstitial; the life cycle is annual. Based on observation of the type material of Theama evelinae Marcus, 1949, the genus Eutheama Faubel, 1983 is synonymized with Theama Marcus, 1949.

No head regeneration here: regeneration capacity and stem cell dynamics of Theama mediterranea (Polycladida, Platyhelminthes)

“…Theama mediterranea was described from the interstitial of the lower intertidal zone all around the Mediterranean Basin (Italy, Greece, Croatia, Israel, France, Tunisia) (Curini-Galletti et al 2008;Gammoudi et al 2017). The almost fully transparent adults are very elongated, reaching a length of about 20 mm and a width of 2.5 mm.…”

“…The almost fully transparent adults are very elongated, reaching a length of about 20 mm and a width of 2.5 mm. They have two rows of a varying number of tentacular eyes and two pairs of cerebral eyes situated directly anterior to the brain (Curini-Galletti et al 2008). The pharynx is located in the middle of the body, and an adhesive pad is located ventrally at the posterior tip of the animal ( Fig.…”

Polyclad phylogeny persists to be problematic

“…Due to their colourful appearance, polyclad flatworms are among the most conspicuous members of the phylum Platyhelminthes, yet these animals are relatively poorly studied (Bahia et al 2017). Usually, polyclads occur in diverse marine habitats, such as under coastal stones, on reefs and in interstitial spaces (Hyman 1951;Prudhoe 1985;Curini-Galletti et al 2008). About 800 to 1000 species of polyclads are currently recognised (Rawlinson 2008;Martín-Durán and Egger 2012).…”

Zoology in the era of biodiversity

“…Whereas accounts on new taxa with some feature of general biological interest (e.g. Curini-Galletti et al 2008) are welcome, as are taxonomic revisions (e.g. Giangrande & Licciano 2008;Rota et al 2008), or reports from poorly known parts of the world (e.g.…”