Praethecacineta halacari ( Schulz, 1933 )

Dovgal, Igor, Chatterjee, Tapas & Ingole, Baban, 2008, An overview of Suctorian ciliates (Ciliophora, Suctorea) as epibionts of halacarid mites (Acari, Halacaridae), Zootaxa 1810, pp. 60-68 : 61-63

Praethecacineta halacari ( Schulz, 1933) , charact. emend

( Fig. 4, 5, 9 –11)

= Thecacineta halacari Schulz, 1933 = Lissacineta allgeni Jankowski, 1981 , syn. n.

= Thecacineta allgeni ( Jankowski, 1981) , syn. n.

Diagnosis: Marine suctorians with stylotheca. Cell body, slightly, laterally flattened, entirely filling the lorica and attached to its posterior margin. Apical part of the body narrowed.

FIGSURES 1–2. Limnoricus ceter Jankowski, 1981 from halacarid mite (2—stalk) (after Jankowski 1981). FIGURE 3. Limnoricus ceter from isopode crustacean (after Jankowski 1981).

Tentacles placed at upper cell surface. Macronucleus spherical, posteriorly located. Contractile vacuole single. Stylotheca smooth, without ribbing. Body dimensions: lorica length 31–38 µm (85–110 µm after Schulz 1933), lorica width 18–21 µm (35–55 µm after Schulz 1933), stalk length 3–26 µm (50–110 µm after Schulz 1933). Reproduction by semi-circumvaginative exogemmic budding with formation of laterally placed ciliary swarmers ( Fig. 10 ). Original measurements of Pra. halacari were made using specimens from Goa, India.

Remarks on the systematics and nomenclature: Pra. halacari was described from marine halacarid mites from interstitial sand ( Schulz 1933) and classified with the genus Thecacineta Collin, 1909 . However, except for Pra. halacari , formation of unciliated swarmers is characteristic for all species of the genus. It was for this reason that Matthes (1956) assigned Pra. halacari to the current genus Praethecacineta Matthes, 1956 and placed it together with the genus Thecacineta in a new family, Thecacinetidae . Finally, in the keys for identification of suctorians of Ukraine ( Dovgal 1996), Praethecacineta was placed into the subclass Exogenia Сollin, 1912 in the new family Praethecacinetidae Dovgal, 1996 , based on the type of budding.

Jankowski (1981) noted that the species identified by Batisse (1965) as Pra. halacari was wrongly identified and proposed the new species name Lissacineta allgeni . The generic name was later synonymyzed by Dovgal (2002) with Thecacineta , and Lis. allgeni was transferred into the genus. However, the absence of lorica ribbing warranted new species erection by Jankowski (1981), while a smooth and slightly folded lorica is characteristic for Pra. halacari . Thus, Jankowski’s species is considered a junior synonym of Pra. halacari .

Distribution and host prevalence: The species was previously observed near the Norwegian coast (Tromsø) and in the Kiel Bay ( Schulz 1933) on unidentified halacarids. Precht (1935) later identified Pra. halacari on Copidognathus spp in the latter locality. Rare instances of the species are also known from the Bulgarian coast of the Black Sea ( Detcheva 1992).

Praethecacineta halacari was found on the legs and body surface (both ventrally and dorsally) of Copidognathus brachystomus Viets from the Black Sea near Karadag Natural Reserve (Kurortnoye, Crimea region, Ukraine; Boshko & Dovgal 2004). It was also recorded in interstitial sand at Cape Martian Reserve near the village of Nikita in the Yalta region (Crimea), from an unidentified halacarid mite ( Gelmboldt & Dovgal 2005).

Among the suctorians observed by Bartsch (1989, 1998, 2001, 2003), we identified several individuals of Pra. halacari on the idiosomas of the following halacarid mites: Cop. brachystomus Viets ( Bartsch 2001), Cop. magnipalpus (Police), and Caspihalacarus hyrcanus Viets ( Bartsch 1998) from Black Sea soft sediment; Cas. hyrcanus from the Caspian Sea ( Bartsch 1998); Cop. brifacius Bartsch from sandy deposits from the North Sea ( Bartsch 1989); and on the idiosoma and gnathosoma of Cop. meridianus Bartsch off the coast of Western Australia ( Bartsch 2003). Furthermore, from the figure in Pepato & Tiago (2005), we have also identified Pra. halacari on the idiosoma of Cop. tupinamborum Pepato & Tiago from the Atlantic coast of Brazil.

In the present study, we have also found Pra. halacari on Cop. arabicus Chatterjee & Chang collected from Goa on the west coast of India (Arabian Sea) ( Figs. 9 –11). Seven of the 33 mites were infested by suctorians. We observed that Pra. halacari was found on Cop. arabicus, but not on species of the co-occurring genera Rhombognathus and Agauopsis . Furthermore, Pra. halacari is reported here for first time from India.

Figures

FIGURE 10. Budding of Praethecacineta halacari (Schulz 1933) (orig.). Scale bar 10 µm. FIGURE 11. The settlement of Praethecacineta halacari on the halacarid mite from India (orig.). FIGURE 12. Thecacineta calix (Schroder 1907) found in the Black Sea (orig.). Scale bar 20 µm.