Pebrilla paguri(Ciliophora, Folliculinidae) on four Mediterranean hermit crab species

Abstract

The present research aims at broadening the range of possible Pebrilla paguri hosts, by analysing various Mediterranean hermit crab species, as well as at investigating their preferential distribution on the crustacean body. For each crab carrying P. paguri on its exoskeleton, the position and number of the ciliate's loricae were recorded and mapped. Pebrilla paguri loricae were observed only on 16.6% of the hermit crabs examined, with a greater number being observed on Calcinus tubularis and Paguristes eremita, compared to the two other crab species. A reason for this may be that the former are not very active in feeding, motion, and interaction. The highest frequency of P. paguri was observed on the abdomen, telson, and uropods, whereas only a few were found on the cephalotorax. This localisation is discussed in relation to the epibiont's preference for parts of the crab's body that are normally kept deep inside the molluscan shell and characterised by scarce water flow and illumination. These conditions will promote bacterial proliferation and accumulation of the organic residuals, which will become available for P. paguri as food. The preferential distribution of ciliates on the left side of the crab's body can be seen as a way to avoid damage by rubbing against the shell's columella.

Finding ofPebrilla paguri(Ciliata, Folliculinidae, Heterotricha) epibiont inside the shells of two hermit crab species,Calcinus tubularisandClibanarius erythropus(Decapoda, Anomura, Diogenidae)

“…Among the latter, for example, Vorticella incostans on the cladoceran Macrothrix hirsuticornis (Fernández-Leborans & Tato-Porto 2000a) and Acineta karamani on the decapod Atyaephyra desmarestii (Fernández-Leborans & Tato-Porto 2000b) are known. Regarding P. paguri, which was never before reported attached to substrata other than the hermit crab, this research shows for the first time that the species is more generalistic than was noted by Faurè-Fremiet (1936), Fernández-Leborans & Herrero Có rdoba (1997) and Basile et al (2004). In fact, loricae also adhere to the inside walls of the shells occupied by the crabs.…”

“…The morphology of the loricae adhering to the inside of shells here analysed is referable to that observed for P. paguri by Faurè-Fremiet (1936), Fernández-Leborans & Herrero Có rdoba (1997) and Basile et al (2004). In each group of protozoan epibionts, there are generalistic species and specific species.…”

“…The crabs were the same used for the research by Basile et al (2004). The shells of all these 81 crabs were examined and 36 (44.4%) of them had P. paguri loricae on their inside walls (Tables I and II): the loricae had the typical specific morphology, already described by Faurè-Fremiet (1936), Fernández-Leborans & Herrero Có rdoba (1997) and Basile et al (2004).…”

“…The crabs were the same used for the research by Basile et al (2004). The shells of all these 81 crabs were examined and 36 (44.4%) of them had P. paguri loricae on their inside walls (Tables I and II): the loricae had the typical specific morphology, already described by Faurè-Fremiet (1936), Fernández-Leborans & Herrero Có rdoba (1997) and Basile et al (2004). All the loricae observed on the shells showed no live ciliate inside but had the same morphology and biometry as the one attached to the crab and showing the ciliate, identified at species level by Basile et al (2004).…”

“…U.Z.I. : 58; Basile et al 2004); P. prideaux and P. excavatus (Fernández-Leborans & Herrero Có rdoba 1997); P. anachoretus, P. cuanensis, Calcinus tubularis and Paguristes eremita (Basile et al 2004). …”