Cothurnia sp.

Ivanova, Еkaterina, Dovgal, Igor V. & Newton, Alice, 2017, Paf + SU: Deposit Limit in Registration, Ecologica Montenegrina 10, pp. 51-57 : 54-56

Cothurnia sp. ( Fig. 4)

Diagnosis. Marine loricate peritrich ciliate with lengthy lorica. There is an external stalk, short and broad, attached to substrate via basal disc, endostyle, present, mesostyle, absent. Contracted zooid occupies nearly the bulk of lorica. Macronucleus rounded, pellicle is only weakly striated. Reproduction was not observed.

Dimensions (in µm): Lorica length 50-80, minimal lorica width 7-8, maximal lorica width 21-30, wall thickness of the lorica 2-4, external stalk length 10-17, contracted zooid length 45-50, width 19-20, dimensions of macronucleus 8X12.

Remarks. On such characters as lorica morphology, the presence of an endostyle, absence of mesostyle and dimensions the found peritrich species is closest to Cothurnia membranoloricata Stiller, 1968 , previously found on marine algae ( Stiller, 1968, Viljoen & van As, 1983). However, in our materials ciliates supplied with rounded macronucleus. In turn in the original description of C. membranoloricata Stiller (1968) does not mentioned the shape of the macronucleus, whereas in description of Viljoen and As (1983) C. membranoloricata showed a horseshoe-shaped macronucleus.

It should be mentioned that in ciliate described of Stiller (1968) the peristomial lip is conspicuously thickened ( Warren & Paynter, 1991) whereas that illustrated by Viljoen & As (1983) is very thin thus, it is not unlikely that in mentioned works two different species were described. At the same time, we have only fixed materials, in which the characters as peristome morphology, the degree to which the zooid extends beyond the lorica aperture, etc were not visible. As a result, now we cannot reliably identify the peritrich species.

The ecological peculiarities of found ciliates

At the methane seepage sediments of the Ria Formosa lagoon ( Bahlmann et al., 2015), the H 2 S rising due to microbial chemotrophic activity. We measured the H 2 S concentration at the bottom water, which was a 0.024 μmol/l at the station B ( Table 2). Any traces of H 2 S were no detected at the station A ( Table 2).

Granulometry sediment composition of both areas was classified as gravely muddy sand (using Wenthwort, 1922). Mean values of redox potential (Eh) across the lagoon sediments ranged from –135 mV at the natural reserved areas up to –323 mV at the city sewage outfall (location of maritime terminal “Cais Comercial”).

Sediment properties analyzed here along with previous study results ( Bahlmann et al., 2015), allow attributing the lagoon sediments to hypoxic (and even periodically anoxic) methane seepage shallow waters environment.

Location Coordinates granulometry μmol/l, Ciliate species Host species composition bottom water

N 37°0′42″ Gravely Muddy

Station A 0 E 7°56′34″ Sand

Cothurnia sp.

Spirinia sp. (2 individuals)

Loricophrya

N 37°0′24″ Gravely Muddy Metachromadoroides

Station B 0.024 bosporica

E 7°54′59″ Sand remanei

(4 individuals)

Host basibionts for both ciliate species from hypoxic and gas enriched sediments of the Ria Formosa lagoon were a nematodes. The nematode Spirinia sp. is dominated the Nematoda community by their abundances (25%) from 20 species reported at the station A. At the same time the nematode Metachromadoroides remanei Gerlach, 1951 also dominated the community by their densities (32%) from the 22 species of Nematoda recorded at the station B.

As folliculinid ciliates living on inanimate substrates were previously found in methane seeps the finds of commensal ciliates in the community is of certain interest. It is believed that the commensal ciliates especially specific commensals or parasites of extremophile hosts are possible specific inhabitants of extreme environments ( Dovgal et al., 2015, Dovgal & Sergeeva, 2016).

However, the hosts of ciliates found at Ria Formosa lagoon are not specific inhabitants of methane seeps. As for ciliate specificity to the nematode hosts only L. bosporica , the species that was identified can be discussed.

L. bosporica from the Black Sea hydrogen sulfide zone settle on Desmoscolex сf. minutus . In our case, the species was attached to the bodies of M. remanei . It appears that the suctorian species is not specific to a particular species of nematodes, but prefers the host species with the well-sculptured cuticle. However, the re-discovery of this suctorian in habitat with deficiency of oxygen and the presence of methane and hydrogen sulfide may be indicative about prevalence of L. bosporica to extreme conditions.