Suctoria, Claparede & Lachmann, 1858

Neuhaus, Birger, Lu, Borong, Yamasaki, Hiroshi & González-Casarrubios, Alberto, 2023, Epibiontic life on intertidal Setaphyes kielensis and S. dentatus (Kinorhyncha, Pycnophyidae) from Sylt, North Sea, Germany, with a description of a new species of Trematosoma (Ciliophora, Acinetidae) and a redescription of Cothurnia buetschlii (Ciliophora, Vaginicolidae), Zootaxa 5343 (5), pp. 439-470 : 460-464

publication ID	https://doi.org/10.11646/zootaxa.5343.5.2
publication LSID	lsid:zoobank.org:pub:2E48E826-9DB3-45C3-B231-CBB84B725119
DOI	https://doi.org/10.5281/zenodo.15298844
persistent identifier	https://treatment.plazi.org/id/F6548788-9916-FF8A-FF33-F9937438FDAA
treatment provided by	Plazi
scientific name	Suctoria
status

Treatment

Acinetid Suctoria

Diagnostic characters of Trematosoma and Limnoricus Jankowski, 1981 . The taxonomy of acinetid Suctoria is quite confusing and species with similar characters like a flattened lorica and one to few rows of tentacles have been grouped in different genera, viz Trematosoma and Limnoricus (see Jankowski 1981; Dovgal 2002; Dovgal et al. 2008; Dovgal & Lozowskiy 2008). Species of Trematosoma , Limnoricus ceter Jankowski, 1981 , and L. seticolus ( Jankowski, 1981) possessed a stalk separated from the lorica, whereas L. ponticus Dovgal & Lozorowskiy, 2008 showed a thecostyle with the lorica gradually diminishing in diameter to the basis ( Pritchard 1852; Maupas 1881; Gruber 1884; Collin 1909; Precht 1935; Guilcher 1950; Allgén 1951; Jankowski 1981; Dovgal & Lozorowskiy 2008; this paper). Based on this observation, Dovgal et al. (2008) discussed placing L. ponticus in a different genus but refrained from this. The differences between L. ceter , L. seticolus , and species of Trematosoma appear to be more species-specific than genus-specific, and at some stage L. ceter and L. seticolus may have to be transferred to Trematosoma .

TABLE 7. (Continued)

Species Character T. amphiasci (Precht, 1935) T. bocqueti ( Guilcher, 1950) T. complatana ( Gruber, 1884) T. constricta (Collin, 1909) T. falcata (Jankowski, 1981) T. ovata (Pritchard, 1852) T. pusilla (Maupas, 1881) T. rotunda (Allgén 1951), T. husselae sp. nov. Arrangement of tentacles one row left and right with ca. 9 tentacles each, small gap one row left and right with 18–20 tentacles each, small gap; [2 short and 2 or 3 long tentacles at each corner of lorica, broad gap] one row left and right with ca. 10 tentacles occurring also laterally, broad gap one row left and right with small gap; [and 11–14 or 8–28 tentacles] one row left and right with 5–6 tentacles each, small gap single row, ca. 11 single row, 4–5 tentacles ca. 12–19 tentacles in one? row one row left and right with 8–16 tentacles each, small gap Length of tentacles short; [11– 12 µm, thick and 48–50 µm, thin] -; [11–12 µm or 48–50 µm] -; [50 µm] long; [30–69 µm; 17–31 µm] very short - short; [10 µm] 4–6 µm; [4 µm] 4–6 µm Endogenous budding not observed yet +, embryo 25 µm x 10 µm not observed yet + not observed yet not observed yet + not observed yet +, embryo 13–15 µm x 8–10 µm Original basibiont; [additional basibionts] Copepoda Copepoda; [on debris] -; [Hydrozoa; Bryozoa] Crustacea: Paguridae green algae Hydrozoa Bryozoa; [algae; Hydrozoa; tubes of Polychaeta; Copepoda] Nematoda Kinorhyncha Original location(s); [additional location] Baltic Sea: Kiel Bight; [Adriatic Sea] English Channel: Roscoff; [Western Australia] Ligurian Sea: Genua English Channel: Roscoff; Mediterranean Sea: Banyul Arctic Ocean, Murmansk North Sea: United Kingdom Algeria: Algier; [Adriatic Sea] Falkland Islands; [India, Sundarbans

North Sea: Sylt]

Remarks, Fernandez- Batisse 1972; Collin 1912; original description described Curds 1985; Curds 1985: this paper additional Leborans et Post et al. 1983 Curds 1985 brief, illustration without Fernandez- Acineta ovoidea references al. 2012 and more detailed name by Leborans et Allgén, 1951 = description in Collin Alder 1851; al. 2012 synonym of T. 1912; Fernandez- Curds 1985 rotunda , because Leborans & Gabilondo just lateral view; 2006; Fernandez- Ghosh & Mandal Leborans et al. 2013 2019

One more distinctive genus-specific character might be the reproduction via semi-circumvaginative budding in L. ponticus versus internal budding in T. bocqueti , T. constricta , T. pusilla , and T. husselae sp. nov.; however, reproduction in L. ceter and L. seticolus is unknown, semi-circumvaginative budding may represent a character of L. ponticus only ( Table 7 View TABLE 7 ; Maupas 1881; Collin 1912; Batisse 1972, 1975; Jankowski 1981; Curds 1985; Dovgal et al. 2008; Dovgal & Lozowskiy 2008; this paper). The differing types of budding within Suctoria were used by Batisse (1975) to justify new taxonomic categories. These types of reproduction were mainly based on cultivated species allowing in-depth studies. Unfortunately, such detailed information is lacking for almost all species of Limnoricus and Trematosoma . Although we had quite a large amount of specimens of T. husselae sp. nov. available, we noticed only swarmers inside the zooid and a swarmer, which seemed to have left its parent (comp. Figs 2A View FIGURE 2 , 4D View FIGURE 4 , and 5A, B View FIGURE 5 with Fig. 4E View FIGURE 4 ). The image provided for L. ponticus about semi-circumvaginal budding did not allow to see that character clearly, so we relied on the statements of the authors (Dovgal et al. 2008, fig. 2B; Dovgal & Lozowskiy 2008, fig. 2).

References

Figures

FIGURE 5. Setaphyes kielensis (A, ZMB 12489; B, ZMB 12500; C, ZMB 12499; D, ZMB 12487; J, ZMB 12486; L, ZMB 12397; M, ZMB 12369) and S. dentatus (E–G, K, ZMB 12503; F, H, I, ZMB 12494) with specimens of Trematosoma husselae sp. nov. (A–G, J–M), Cothurnia buetschlii (J), and a case of fungus or developmental artefact (H, I, ZMB 12494), DIC. A. Segments 1–4, lateral and dorso-ventral view on the calyciform, dorso-ventrally compressed lorica with the zooid, ventrolateral view on basibiont. B. Epibiont with swarmer, stalk, and lorica in optical section. C. Epibiont with two macronuclei not fusing at any focal level. D, E. Young, small, spherical epibionts with few tentacles, not all tentacles in focus. F. Young specimen on cuticle of basibiont with striation pattern on surface (arrows). G. Epibiont with tentacles in empty shell of suctorian epibiont. H, I. Segment 10, dorsally (H) and optical section (I), subcuticular fungus or internal sclerotisation artefact of the cuticle (arrows). J. Assemblage of epibionts on segment 10 of basibiont with C. buetschlii (contracted specimen left, extended specimen right), T. husselae sp. nov., and two kinds of filamentous bacteria. Arrows mark endostyle. K. Suctorian on segment 7 of S. dentatus. L, M. Specimens collected 1998, showing cellular substructures (L) and withdrawn zooid with minimum amount of cellular substructures (M). Extended focus images of six (D), eight (H, L), and three (K) images. Arrowheads mark stalks in B, D, E, G, and J. Abbreviations: ba, bacteria; ca, basal cavity in lorica; co, C. buetschlii; en, endostyle; lo, lorica; ma, macronucleus; s, segment, followed by segment number; sc, spherical cavity; sp, sperm; st, stalk; su, suctorian epibiont; sw, swarmer; te, tentacle; tu, tube on segment 2. Scale bar in A 50 µm, in B 20 µm, valid for B, G–J and M, in C 20 µm, valid for C, K, and L, and in D–F 10 µm.

Tables

TABLE 7. Comparison of characters of species of Trematosoma after original descriptions and additional references. Unique characters marked in bold. Abbreviations: -, information about character not available; +, character present; [], information from additional reference(s).?, character appeared questionable or unclear in our interpretation; SEM, scanning electron microscopy.

Species Character	T. amphiasci ( Precht, 1935)	T. bocqueti ( Guilcher, 1950)	T. complatana ( Gruber, 1884)	T. constricta ( Collin, 1909)	T. falcata ( Jankowski, 1981)	T. ovata ( Pritchard, 1852)	T. pusilla ( Maupas, 1881)	T. rotunda ( Allgén, 1951)	T. husselae sp. nov.
Shape of lorica/ specimen	calyciform	almost rectangular, slightly indented in middle part apically and around stalk	almost rectangular, lorica expressed only as basal disk; [basal lorica convex; zooid can leave stalk, and live free or attach with tentacles]	bowl-shaped, anterior waist-like indentation on each lateral edge, slightly indented around stalk, zooid protruding anteriorly	bowl-shaped with broad base and protruding anteriorly	ovate, bowlshaped, bluntly truncate apically	calyciform with zooid protruding anteriorly	ovate	calyciform
Lorica, surface	-	-	-	-	regularly annulated surface with ca. 20 rings	-	-	surface finely annulated	surface with slightly elevated rings (SEM only)
Length of lorica/ specimen	27–50 µm?, [31–33 µm]	20 µm; [ca. 20 µm]	<30 µm	50–60 µm; [10–35 µm; 25–27 µm]	35–50 µm	-	-; [60 µm; 47–58 µm]	27–33 µm; [ca. 19 µm]	30–47 µm
Width of lorica	27–50 µm?, [12–15 µm]	30 µm; [20 µm]	30 µm	45 µm; [89–217 µm?; 26–30 µm]	40–47 µm	-	-; [50 µm; 41–50 µm]	23–29 µm; [ca. 13 µm]	26–34 µm
Position of zooid in lorica	small cavity at base	filling lorica	filling lorica	filling lorica	filling lorica	-	small [very large] cavity at base of lorica	zooid in anterior 1/2–2/3 of lorica	filling lorica, occasionally small cavity at base
Length of stalk	as long as lorica; [9–25 µm]	short; [4.5 µm]	longer than specimen; [60 µm or attached with tentacles only]	80 µm; [138–148 µm; 69–126 µm]	26 µm	about as long as lorica	18 µm; [10–20 µm]	7–16 µm; [ca. 4 µm]	5–7 µm
Width of stalk	8 µm; [3–4 µm]	-; [4 µm]	-	-; [20–35 µm]	thin	slender	1 µm; [2 µm]	2 µm [ca. 3 µm]	3–4 µm
Stalk, other characters	-	-; [basal disc 7–10 µm diameter]	-	longitudinal striae	small basal disk	[smooth]	-	finely annulated; [transversal striae]	longitudinal striae, no basal disk