3.2. Taxonomic Account of Ciliates: Systematic Position
Class SUCTOREA Claparède et Lachmann, 1859
Subclass EXOGENIA Collin, 1912
Order METACINETIDA Jankowski, 1978
Family PARACINETIDAE Jankowski, 1975
Genus Loricophrya Matthes, 1956
Loricophrya susannae n. sp. (
Figure 2A,B)
Etymology: The specific name is in memoriam of Prof Susanna De Zio for her basic contribution to the taxonomy of marine meiobenthic Tardigrada.
Diagnosis: Suctorian ciliate covered with conical, smooth, transparent, weakly bent, stylotheca. Pseudostyle short, thin, curved, longitudinally striated (
Figure 2A). The cell body entirely covered by stylotheca, attached to the lorica in the mouth area. There are about 15 thin, flexile tentacles. Macronucleus ovoid, centrally located.
Morphological description: Suctorian ciliate covered with conical, smooth, transparent, weakly bent, lorica (stylotheca 70 × 44 μm). The stalk-like protuberance of lorica (pseudostyle 10 μm in length) is shorter than the lorica itself, thin, curved, provided with longitudinally striae, expanded in plate in zone of contact with substrate (
Figure 2A,B). The cell body unflattened, entirely covered by stylotheca, attached to the lorica in the area of aperture. The cytoplasm colorless, contains some dark inclusions (
Figure 2A). There are about 15 thin, flexile tentacles (22–57 μm in length) with characteristic terminal knobs. Tentacles are evenly distributed at the apical body surface. Macronucleus relatively large, spherical (18 × 15 μm), centrally located. Reproduction not observed.
Measurements, based on two individuals (in μm): Stylotheca length 70, maximal stylotheca width 44, pseudostyle length 10, pseudostyle diameter 1, epicone length 6, width 6, body length 52, body width 36, macronucleus length 18, width 15, tentacle length 22–57.
Differential diagnosis: Genus
Loricophrya Matthes, 1956 include 11 species (12, [
47]), however the new species is relative to
L. parva (Schulz, 1932), from which differs by presence of thin, striated pseudostyle and conical (nor urn-like), bent, stylotheca. In addition, in all known representatives of the genus the cell body is not entirely covered by stylotheca.
Type material: Permanent microscopic slides of nematodes with the new suctorian species were deposited at REM/EEP/LEP of Ifremer Centre Brest, Brittany, France.
Type locality: Secca delle Fumose, Gulf of Naples, Italy.
Type host: Chromaspirina sp. and Perspiria sp.
Order VERMIGEMMIDA Jankowski, 1973
Family THECACINETIDAE Matthes, 1956
Genus Thecacineta Collin, 1909
Thecacineta fumosae n. sp. (
Figure 3A,B)
Etymology: The species name refers to the locality name, Secca delle Fumose.
Diagnosis: Marine loricate suctorian. Cell body attached to the bottom of lorica. The apical part of body narrowed, not protruded from lorica aperture. Up to 12 capitate tentacles placed at apical body surface. Macronucleus spherical, located in the middle of body. Lorica slightly curved, smooth, transparent, without any ribs. The mouth of lorica is some wider than the rest. Stalk short, curved, with good developed, conical epicone, which have the same width as bottom of lorica (
Figure 3A). Reproduction not observed.
Morphological description: Marine. Cell body granulated, colorless, attached to the bottom of lorica. The basal part of two thirds of the cell body flared, then body to become narrow, but with weakly enlarged apical part, bearing tentacles. The cell body not protruded from lorica aperture. Up to 12 capitate tentacles (23–33 μm in length) evenly distributed at apical body surface. Macronucleus ovoid, located in the middle of body (
Figure 3B). Lorica (82 μm in length and 27 μm in width) slightly curved, smooth, transparent, without any ribs or striae (
Figure 3A). The aperture of lorica (29 μm in diameter) is some wider than the rest, with somewhat arched annular edge. The stalk (14 μm in length) is clearly delimited from lorica, short, weakly curved, without any folds or striae, with good developed, conical epicone, which have the same width as bottom of lorica in the area of contact with them (
Figure 3B).
Measurements, based on one individual (in μm): Lorica length 82, lorica width 27, lorica aperture diameter 29, body length 78, body width 20, stalk length with epicone 14, diameter 11, maximal epicone diameter 33, length of tentacles 23–33.
Differential diagnosis: The new suctorian species differs from the relative species as
Thecacineta cothurnioides (Collin, 1909) recorded on harpacticoid copepod
Cletodes longicaudatus from Banyuls-sur-Mer at Mediterranean coast of France [
48] and nematode
Tricoma sp. from Ratnagiri, west coast of India, Indian Ocean [
49] and
Thecacineta urceolata [
26] found on nematode
Desmodora pontica from Ludao, Taiwan by its curved lorica, stalk with wide, conical epicone. From other species of the genus the new species differs by its transparent lorica.
Type material: Permanent slide of the nematode with the new suctorian species was deposited stored at REM/EEP/LEP of Ifremer Centre Brest, Brittany, France.
Type locality: Secca delle Fumose, Gulf of Naples, Italy.
Type host: Perepsilonema sp.
Subclass ENDOGENIA Collin, 1912
Order ACINETIDA Raabe, 1964
Family ACINETOPSIDAE Jankowski, 1978
Genus Acinetopsis Robin, 1879
Acinetid ciliates with tentacles of two types: hypertrophied, agile, prehensile ones, and regular feeding (sucking) ones [
50]. The body is trapezium-like, laterally flattened, loricate and stalked. The macronucleus is spherical or ovoid.
In accordance with Dovgal [
17], there are three species of the genus:
Acinetopsis rara [
51] (type species),
A. tentaculata [
52] and
A. elegans [
53].
However, the species found of Swarczewsky [
53] on gills of amphipod crustacean
Carinurus solskii from Baikal Lake were not provided with lorica and thus must be excluded from the genus
Acinetopsis. It is Jankowski’s opinion [
54] that the species is representative of genus
Tokophrya Bütschli, 1899.
A. rara (
Figure 4(1)) was found [
51] on hydroids from genus
Sertularia collected near Concarneau (France). The ciliate is from 70 to 90 μm (in accordance with [
51]), covered with stalked lorica, the height of which is one third less than its width. The stalk is very thin, 100 μm long. The body is uniformly granular, greyish, with a small contractile vacuole, a flat apical surface, from the centre of which one contractible tentacle extends. The body does not reach the bottom of the lorica. As observed by Grell and Meister [
55] the
A. rara feeds on representatives of genus
Ephelota that is often far greater than the predator. The sucking tentacles of
A. rara are much smaller and bear knobs devoid of haptocysts. The prehensile tentacles are ordinary in structure but, on the contrary, gigantic, very lively and enriched with haptocysts [
55]. The original figure of Batisse [
56] illustrates that, in addition to the central trapping tentacle, there are two groups of 12–13 thin, short sucking tentacles.
Acinetopsis tentaculata [
52] (
Figure 4(2)) has a body enclosed in a flattened, cup-shaped lorica, borne on a slender stalk, of which some are longer than the lorica. The body is irregularly flattened-ovoid in shape, bearing one or two agile prehensile tentacles and two groups of small sucking tentacles on its apical surface. The macronucleus is ovoid; there are also one or more micronuclei. A single contractile vacuole is located near base of the body. Reproduction occurs by endogenous budding.
Measurement (in μm, in accordance with Root, [
52]): Lorica length 187, width 105, body length 138, width 100, thick 73, length of stalk 287, extended prehensile tentacle length 500.
Locality: Woods Hole, USA.
Host: Ephelota coronata Wright, 1858 found on hydroids Obelia commissuralis and O. geniculata.
Jankowski [
54] believed that the
A. tentaculata is a younger synonym of
A. rara.
Etymology: The specific name is in honor of outstanding protistologist Denis Lynn (1947–2018).
Diagnosis: Suctorian ciliate enclosed in a flattened, narrow, elongate, smooth lorica with short extended upward stalk. Body attached to the bottom of lorica and fills about two thirds or three fourths of it. There are two agile hunting tentacles and from three to four short, contractile sucking tentacles. The macronucleus is ovoid, positioned near foot of the body. Reproduction occurs by endogenous budding with formation of single protomite (
Figure 5A,B).
Morphological description: Marine suctorian ciliate enclosed in stalked lorica. The cell body is attached to the bottom of lorica, which fills about two thirds or three fours of it. Cytoplasm colorless and faintly granulated, with numerous inclusions (
Figure 5B,C). The apical body surface, which bearstentacles, is noticeably concave downward. Lorica elongate (49–62 μm × 17–19 μm), somewhat expanded, slightly flattened, smooth, but with two or three annular striae on the inside of walls in the top. Stalk short (5–7 μm × 2–4 μm), straight, some extended upward, very weakly longitudinally striated, with adhesive disc. There are two extremely long (about the same length as body), agile hunting tentacles (27–46 μm) and from three to four short, contractile sucking tentacles (5–10 μm × 1–2 μm). Macronucleus ovoid, positioned near foot of the body. Reproduction by endogenous budding with the formation of single protomite. Protomite relatively large (24 μm × 11 μm), its length makes up more than half of the body length (
Figure 5B–D).
Measurement, based on four individuals (in μm): Lorica length 49–62, lorica width 17–19, lorica aperture diameter 12–20, body length 36–41, body width 14–18, macronucleus diameter 7–9, stalk length 5–7, stalk diameter 2–4, prehensile tentacle length 27–46, sucking tentacle length 5–10, sucking tentacle diameter 1–2, protomite length 24, width 11.
Differential diagnosis: The new species differs from other representatives of the genus by narrow, elongated lorica, short stalks, and the presence of only three to four contractile sucking tentacles. In addition, the cell body of the new species does not fill all lorica.
Type material: Permanent slide of the nematode with the new suctorian species was deposited and stored at REM/EEP/LEP of Ifremer Centre Brest, Brittany, France
Type locality: Secca delle Fumose, Gulf of Naples, Italy.
Type host: Desmodora sp.