Proseriate flatworms from sandy beaches in the Western Mediterranean Sea

Study Extent

We sampled 116 beaches through Spain (22 beaches, including Balearic Islands), France (25 beaches, including Corsica), Italy (63 beaches, including Sardinia, Sicily, and Lampedusa), and Tunisia (6 beaches).

Sampling

Each beach was sampled once between May 2020 and June 2022. In each of the three levels of each beach, 6 litres of sediments were samples using plastic jars from the 5 cm upper sand, where most of the proseriate flatworms occur.

Quality Control

Taxonomic identification was performed by the same person, Marco Curini-Galletti, in a short period of two years. Taxonomic identification was always performed comparing animals with the collection of slides and photographs of Marco Curini-Galletti. Georeferenced data were double checked plotting coordinates on a map.

Method steps

1. Each sample was studied within 24-48 hours after collection. The sediment from each sample was placed in an isotonic dilution of magnesium chloride for 15 minutes in order to anesthetize the bulk meiofauna. The supernatant containing the meiofauna was filtered five times through a stack of sieves of decreasing mesh size (1 mm, 0.5 mm, 0.25 mm, 0.125 mm, 0.063 mm).
2. Each sieve was placed in a different petri dish with clean seawater, allowing the animals to recover and crawl through the sieve. The proseriates were picked from the dishes using glycerine-coated pipettes, sorted into different genera under the stereomicroscope, whole mounted alive and identified to species using a compound microscope.
3. Relevant individuals were fixed in Bouin or preserved in 95% ethanol and stored in the collection of Marco Curini-Galletti.
4. Animals belonging to undescribed species were assigned to unofficial but consistent codes for all the studied beaches.

Platyhelminthes: Rhabditophora: Proseriata of the genera Archilina, Archimonocelis, Archotoplana, Boreocelis, Calviria, Coelogynopora, Duplominona, Duploperaclistus, Inaloa, Invenusta, Minona, Monocelis, Monostichoplana, Monotoplana, Napoliplana, Necia, Nematoplana, Notocaryoplana, Notocaryoplanella, Orthoplana, Otoplana, Paradoxoplana, Parotoplana, Parotoplanella, Peraclistus, Phylosirtis, Polystyliphora, Postbursoplana, Praebursoplana, Pseudomonocelis, Vannuccia, Xenotoplana and Yorknia

1. Platyhelminthes
   rank: phylum
2. Rhabditophora
   rank: class
3. Proseriata
   rank: order

Western Mediterranean Sea