JMBA2 - Biodiversity Records Published on-line Occurrence of Polycarpa kornogi in the Mediterranean Sea Nadia Chebbi* ‡ , Francesco Mastrototaro † and Hechmi Missaoui* *Département Halieutique, Institut National Agronomique de Tunis (INAT), 43 Avenue Charles Nicole 1083 Tunis, Tunisie. † Dipartimento di Zoologia, Univesità degli Studi di Bari, Italy. ‡ Corresponding author, e-mail: nadia.chebbi@gmail.com This work announces the occurrence of the stolidobranch ascidian Polycarpa kornogi in the central Mediterranean in Sidi Raïs in the north of Tunisia. A description of the specimens is included as well as some environmental parameters. INTRODUCTION Polycarpa kornogi Glémarec and Monniot C., 1966, was described from specimens collected along the Atlantic southern Brittany coast (Figure 1). It has often been confused with other species of Polycarpa. Vàzquez et al. (1995) sorted the Polycarpa species of the Atlantic and Mediterranean coasts into four main groups, namely the ibrosa, the pomaria, the gracilis and the bathyal-abyssal group. Polycarpa kornogi belongs to the ibrosa group characterised by a sediment-covered tunic. This species is distinguished from the others belonging to Polycarpa ibrosa sensu lato only by internal characters such as the extremity of the anus, the number of gonads (more than 20–30 on each side in P. kornogi and about 12 in P. ibrosa) and especially the form and structure of the elongated polycarps (Glémarec & Monniot, 1966; Vàzquez et al., 1995). This species has also been found along the Norwegian coast at 250 m depth (Monniot & Monniot, 1979) (Figure 1). In this paper the occurrence of P. kornogi along the Tunisian coast is reported for the irst time. MATeRIAl AND MeTHODS Polycarpa kornogi was collected by SCUBA diving along the Gulf of Tunis and more precisely off Sidi Raïs (Figure 1) during an ascidian inventory along the Tunisian coast. Four seasonal campaigns were carried out from January to December 2006. The salinity and water temperature were seasonally recorded using a probe (type WTW microprocessor conductivity Meter lF 196). The samples were collected on Cymodocea nodosa and Posidonia oceanica meadows at depths ranging from 5 to 9 m. The ascidians were anaesthetized with menthol crystals in sea water and then preserved in sea water formalin 5%. The morphological observations and descriptions were made at the Halieutic resources laboratory of the INAT and were conirmed at the Department of Zoology of the University of Bari in Italy. ReSUlTS During the period of investigation the salinity ranged from 37. 2 psu (January 2006) to 37. 6 psu (August 2006) (Figure 2) and the water temperature from 10°C (January 2006) to 26°C (August 2006) (Figure 3). Figure 1. Distribution of Polycarpa kornogi • in the Atlantic (along the Brittany and Norwegian coast and ? possibly Portugal) and  in the Mediterranean (Iberian Province) and new inding along the Tunisian coast. Figure 2. Seasonal salinity variation recorded in Sidi Raïs between January and December 2006. Figure 3. Seasonal water temperature variation recorded in Sidi Raïs between January and December 2006.