Trematosoma rotunda ( Allgén, 1952 )

Chatterjee, Tapas, Sautya, Sabyasachi, Dovgal, Igor, Gaikwad, Santosh, Khokher, Sanofar H. & Choudhury, Amita, 2022, Report of deep-sea epibiont ciliates (Ciliophora) from more than 1000 m depth of the Arabian Sea, Indian Ocean, Zootaxa 5120 (3), pp. 423-434 : 429-430

Trematosoma rotunda ( Allgén, 1952)

( Fig. 3 E–F ; Fig. 4 A )

(for synonym see Chatterjee et al. 2020e)

Material examined: One individual found as epibiont on nematode host collected from stn MUC-13, at 0–2 cm sediment depth, 1495 m water depth ( Fig. 3 E–F ); four individuals found as epibiont on nematode host belongs to the genus Tricoma collected from stn MUC-17, at 0–2 cm sediment depth, 3918 m water depth ( Fig. 4 A ) from Arabian Sea , Indian Ocean .

Diagnosis: Marine loricate suctorian. Cell body short, rounded, laterally flattened, entirely fills up the lorica and clamped to their aperture border. Lorica delicate gently striated. Tentacles clavate, short, arranged in two groups of rows at the upper body surface. Macronucleus spherical or oval, centrally or slightly posteriorly located. Stalk short, thin, slightly ribbed.

Measurements from present find (based on three individuals, in μm): Lorica length 27–31, lorica width 13–16, stalk length 6–13, body length 17–23, body width 12–14, macronucleus diameter 5–6, length of the tentacles 3–4.

Host and substrate specificity: Epibiont on nematodes Desmodora tenuispiculum Allgén, 1928 , Desmodora stateni Allgén, 1928 ( Allgén 1952) ; on nematode Pseudochromadora sp. ( Dovgal 2009) ; on nematode Chromaspirina sp. ( Bhattacharjee 2014) ; on nematode Dorylaimposis punctata ( Ansari & Bhadury 2016) ; on nematode Desmodora scaldensis de Man 1889 ( Ghosh & Mandal 2019); on Desmodora sp. ( Baldrighi et al. 2020); on nematode— Tricoma sp. ( Chatterjee et al. 2020d, present report); on harpacticoid copepod ( Chatterjee et al. 2020e); on nematode (present report).

Distribution: Falkland Islands Allgén (1952); Argentina ( Allgén 1952); Antarctica ( Allgén 1952); Ratnagiri, Maharastra, west coast of India, Arabian Sea ( Dovgal et al. 2009); Odisha, India, Bay of Bengal ( Bhattacharjee 2014); Sagar Island, Sundarbans, India, Bay of Bengal ( Ghosh & Mandal 2019); Karwar, Karnataka, India, Arabian Sea ( Chatterjee 2020d); Goa, west coast of India, Arabian Sea (Chatterjee et al. 2000e); Madagascar, Indian Ocean (528–775 m depth) ( Baldrighi et al. 2020); Gulf of Naples ( Baldrighi et al. 2020); Arabian Sea, 1495 m and 3918 m depth (present report).

Remarks: Earlier report of Baldrighi et al. (2020) of this species was from 528–775 m depth of Madagascar region, Indian Ocean. Present record of this species extends its bathymetric distribution up to 3918 m depth in Indian Ocean.

Figures

FIGURE 3. A–B. Loricophrya cf. stresemanni (Allgén, 1951) on nematode body; C–D. Acinetides gruberi Curds, 1985 on nematode; E–F. Trematosoma rotunda (Allgén, 1952) on nematode.

FIGURE 4. A. Trematosoma rotunda (Allgén, 1952) on nematode host; B–D. Brachyosoma sp. on ostracod host; 1—trophont of Brachyosoma sp., 2—vermiform suctorian swarmer.