The Cost for Biodiversity: Records of Ciliate–Nematode Epibiosis with the Description of Three New Suctorian Species

Abstract

Epibiosis is a common phenomenon in marine systems. In marine environments, ciliates are among the most common organisms adopting an epibiotic habitus and nematodes have been frequently reported as their basibionts. In the present study, we report several new records of peritrich and suctorian ciliates-nematode association worldwide: from a deep-sea pockmark field in the NW Madagascar margin (Indian Ocean), from a shallow vent area in the Gulf of Naples (Mediterranean, Tyrrhenian Sea), in a MPA area in the Gulf of Trieste (Mediterranean, Adriatic Sea), from a mangrove system in French Guiana (South America, Atlantic Ocean), and from the Maldivian Archipelago. In addition, three new species of Suctorea from the Secca delle Fumose shallow vent area (Gulf of Naples) were described: Loricophrya susannae n. sp., Thecacineta fumosae n. sp. and Acinetopsis lynni n. sp. In the light of these new records and data from the existing literature, we discuss the suctorian–nematode epibiosis relationship as a lever to biodiversity.

First Assessment of the Benthic Meiofauna Sensitivity to Low Human-Impacted Mangroves in French Guiana

“…However, we observed Desmodora with epibionts only at stations 1 and 2 (Figure 6). These epibionts, classified as suctorian ciliates [104], were found almost exclusively on the genus Desmodora: station 1 has lower epibionts values (2.2%) than station 2 (23.5%). A co-occurrence between epibionts and organic contaminants may support the fact that this epibiosis could be the result of a decrease in the immunity of organisms induced by stress, such as disrupted environmental conditions.…”

“…Ciliate epibiosis is a common phenomenon in marine nematodes. As recently reported [104], the presence of epibionts on nematodes cuticle (which is involved in vital functions such as exchange of gases and nutrients, info-chemicals, and defense metabolites) can have a high cost for the host. Two to three epibionts already cause stress for the basibiont whereas more than five epibionts increase the energetic demand for locomotion [105].…”

“…Two to three epibionts already cause stress for the basibiont whereas more than five epibionts increase the energetic demand for locomotion [105]. Furthermore, it has been shown that in a variety of marine ecosystems, the presence of epibionts on nematodes was reported only in the most stressful condition sites (both due to anthropogenic actions or naturally extreme conditions) [104]. The occurrence of epibionts in a mangrove ecosystem could be due to habitat heterogeneity and the nature of anthropogenic disturbance [106].…”

“…The occurrence of epibionts in a mangrove ecosystem could be due to habitat heterogeneity and the nature of anthropogenic disturbance [106]. Environmental stressful conditions can promote epibiosis because nematodes are more vulnerable and easily infested ( [104] ; and references therein) promoting the use of epibiosis as ecological indicator in the assessment of ecological mangrove status. We classified the majority of nematodes as epistrate feeders, as previously reported [107].…”

Report of Trematosoma rotunda (Ciliophora, Suctorea) as epibiont on harpacticoid copepod from western Indian coast

“…Bhattacharjee 2014, Ansari and Bhaduri (2016), Ghosh and Mandal (2019) reported the same species on the nematode host from Bay of Bengal, Indian Ocean. Baldrighi et al (2020) found this species on nematode from NW Madagascar margin-deep sea pockmark and Gulf of Naples-shallow vent area.…”