Contribution to the knowledge of Loxosomatidae ( Entoprocta ) from the Chafarinas Islands ( Alboran Sea , Western Mediterranean )

The composition of the marine benthic community of the Chafarinas Islands, a small group of islands just off the western part of the Moroccan Mediterranean coast, has attracted a high interest, as shown by studies on different animal groups such as Polychaeta (López & San Martín, 1996, 1997; López et al., 1996, 1997; López & Tena, 1999; López & Viéitez, 1999), Isopoda (Castellanos et al., 2003), Nemertea (Frutos et al., 1998), Phoronida (Emig et al., 1999), Pycnogonida (Munilla & Nieto, 1999), and Hydroidea (Peña Cantero & García Carrascosa, 2002). Nevertheless, up to now, no studies are available on Entoprocta from these islands. With the aim to partially fill this gap, solitary entoprocts (the family Loxosomatidae) inhabiting sponges were collected by scuba diving at 7 metres depth at the Chafarinas Islands (Alboran Sea, SW Mediterranean), particularly in Muelle del Titán (Isabel II island) (2o25’44” W, 35o10’46” N) on 22 and 28 June 2008 (Fig. 1). Sponges with entoprocts on the surface were identified as Ircinia fasciculata (Pallas, 1766) and Sarcotragus spinosulus Schmidt, 1862. Only some of the sponges were covered with entoprocts. Sponge samples of approximately 2 cm with loxosomatids were collected and transported in a refrigerator to the laboratory, where they were photographed in vivo and studied further. After photography the specimens were kept in seawater with menthol crystals for approximately 8 hours to obtain a more appropriate relaxation and afterwards Contribution to the knowledge of Loxosomatidae (Entoprocta) from the Chafarinas Islands (Alboran Sea, Western Mediterranean)

With the aim to partially fill this gap, solitary entoprocts (the family Loxosomatidae) inhabiting sponges were collected by scuba diving at 7 metres depth at the Chafarinas Islands (Alboran Sea, SW Mediterranean), particularly in Muelle del Titán (Isabel II island) (2º25'44" W, 35º10'46" N) on 22 and 28 June 2008 (Fig. 1).Sponges with entoprocts on the surface were identified as Ircinia fasciculata (Pallas, 1766) and Sarcotragus spinosulus Schmidt, 1862.Only some of the sponges were covered with entoprocts.Sponge samples of approximately 2 cm 2 with loxosomatids were collected and transported in a refrigerator to the laboratory, where they were photographed in vivo and studied further.After photography the specimens were kept in seawater with menthol crystals for approximately 8 hours to obtain a more appropriate relaxation and afterwards Contribution to the knowledge of Loxosomatidae (Entoprocta) from the Chafarinas Islands (Alboran Sea, Western Mediterranean) L. Sánchez-Tocino & J. M. Tierno de Figueroa Departamento de Biología Animal.Facultad de Ciencias.Universidad de Granada.18071, Granada, Spain.Fax: +34 958243238, E-mails: lstocino@ugr.es,jmtdef@ugr.esfixed in 4% formalin in sea water.The study of this material showed the occurrence of three species.Two of them could be clearly identified as Loxosomella pes (Schmidt, 1875) (Fig. 3) and Loxosomella ameliae Sánchez-Tocino & Tierno de Figueroa, 2009 (Fig. 2).The third taxon could be assigned to the species Loxosomella tethyae (Salensky, 1877) (Fig. 4), but the characteristic eight rows of glandular cells of the stalk could not be clearly observed.Nevertheless, all the remaining characteristics [10 tentacles in the calyx, small wings in the calyx (although not well observed in live individuals), stomach with pentagonal shape, glandular cell row around the base of tentacle crown and also in the lateral wings, etc.] and the     biometric data (see Table 1) led us to identify these individuals as L. tethyae.Loxosomella pes has been previously reported from Italian Tyrrhenic waters (Prenant & Bobin, 1956;Nielsen, 2008), and recently also registered in the Southern Iberian Peninsula, particularly from the Granada province coast (Sánchez-Tocino & Tierno de Figueroa, 2009).This species has been collected previously on sponges of the genera Euspongia Bronn, 1859 [now considered a synonym of Spongia Linnaeus, 1759], Sarcotragus Schmidt, 1862 and Ircinia Nardo, 1833 (Nielsen, 2008;Sánchez-Tocino & Tierno de Figueroa, 2009).In our study it was found on Sarcotragus spinosulus.
Loxosomella ameliae has only been recorded from the Granada province coast living on Ircinia fasciculata (Sánchez-Tocino & Tierno de Figueroa, 2009).In Chafarinas islands, it was also found on the same sponge.
Loxosomella tethyae has been previously reported from sponges of the genera Tethya Lamark, 1814 and Stylotella Lendenfeld, 1888 (the latter is now considered as a synonym of Hymeniacidon Bowerbank, 1858) in some areas of the western Mediterranean Sea (see Nielsen, 2008) and on Microciona Bowerbank, 1862 from Atlantic waters of USA (Nielsen, 1966).In our study it was found on Sarcotragus spinosulus, where it was the dominant species while only a few individuals of L. pes were observed.
The collection of the three loxosomatid species, L. ameliae, L. pes and L. tethyae, is the first record of Entoprocta from the African Mediterranean coast.

Fig. 2 .
Fig. 2.-Calyx of a live individual of Loxosomella ameliae showing the glandular cell rows around the tentacle crown base (scale 100 µm).

Fig. 4 .
Fig. 4.-Live individual of Loxosomella tethyae showing the small lateral calyx wings, the glandular cell row around the tentacle crown base and an attached developed bud (scale 100 µm).