Paracineta
Paracineta Collin, 1911 (ref. ID; 2013)
Class Kinetofragminophora: Subclass Suctoria: Order Suctorida: Suborder Exogenina (ref. ID; 2013)
[ref. ID; 2013]
Body spherical to ellipsoid in shape with much of it protruding out from a cup-shaped lorica. The lorica may be elongated posteriorly but it always terminates in a true stalk. Tentacles arise and radiate out from all of that portion of the body that protrudes from the lorica. Reproduction is by exogenous buds.
Most easily confused with Caracatharina which does not protrude from the lorica and which by invaginative budding, produces a warmer which has ciliation covering the entire ventral surface. In addition Caracatharina's conjugation type represents anisogamy and partial conjugation of adult individuals.
Quote; Colin R. Curds "British and other freshwater ciliated protozoa Part I Ciliophora: Kinetofragminophora" Cambridge University Press, 1982 (ref. ID; 2013)
- Paracineta homari Sand, 1901
Syn; Acineta homari Sand, 1901
- Paracineta lauterborni Sondheim, 1929 (ref. ID; 4861) reported author and year? (ref. ID; 191)
- Paracineta limbata (Maupas) (ref. ID; 1618)
Syn; Podophrya limbata Maupas (ref. ID; 1618)
- Paracineta patula (ref. ID; 191)
- Paracineta pleuromammae Steuner (ref. ID; 1335)
Paracineta lauterborni Sondheim, 1929 (ref. ID; 4861) reported author and year? (ref. ID; 191)
Descriptions
Adult cell: Oviform to pyriform, anterior end in well-fed specimens usually hemispherically protruding from lorica opening. Posterior end with short, narrow or broad stalk-like elongation attached to centre of lorica base; elongation not recognizable in well-fed specimens which fill lorica completely; smaller individuals leave some space between lorica and cell, especially in widened posterior half. Macronucleus in centre of cell, spherical to slightly ellipsoid, contains large central nucleolus. Single ellipsoid micronucleus with distinct membrane attached to macronucleus. 2 contractile vacuoles opposed or slightly diagonally opposed in or near mid-body. Up to 50 tentacles in single bunch on anterior surface of body, tentacles up to 50 um long, distal end distinctly knobbed. One specimen occupied lorica in wrong direction, i.e. with tentacles directed to posterior end of lorica. Cytoplasm densely granulated by 1-2 um sized lipoid droplets. Feeds on various ciliates (Leptopharynx costatus, Cyrtolophosis mucicola), especially on Colpoda maupasi of which up to 10 specimens are sometimes simultaneously attached other tentacles of a single predator. (ref. ID; 4861)
Lorica: Size and shape highly variable, truncated pyriform, ellipsoid or cylindroid, usually widest near base where it is fixed to soil particles by short cylindrical or posteriorly narrowing stalk rarely half as long as lorica; often distinctly asymmetrical because one side more vaulted than other and/or stalk slightly bent. Shape of lorica opening likewise highly variable, i.e. circular, ellipsoid or even almost rectangular, in side view often like a figure 8 because margins higher than centre. 2-8, on average 5 lorica corrugations, first corrugations forms border of lorica opening; corrugations slanted slightly backwards, sometimes incomplete forming indistinct spairals. Lorica material firm, colourless to brownish, distinctly striated longitudinally between corrugations. (ref. ID; 4861)
Budding and Swarmer: Budding commences on the anterior surface with the production of a short, narrow kinety band dividing the tentacle bundle. The macronucleus and the micronucleus elongate. The kinety band consists of 9-11 ciliary rows and is passed to the oviform and leaf-like flattened swarmer which has a size of about 45x30 um; its posterior end is often slightly indented at the site of the contractile vacuole. Old swarmers become longer and narrower and have few to many short tentacles. The macronucleus is irregularly ellipsoid, and there are at least 2 micronuclei often far away from the macronucleus. Like the adults, the swarmers have two contractile vacuoles, one in the anterior third between the ciliary rows and another near the posterior end. (ref. ID; 4861)
Identification and synonymy
My observations agree perfectly with those of Sondheim (1929), who discovered P. lauterborni in a dried and rewetted mud sample from Madagascar. A previously unrecognized synonym is Thecacineta edmondsoni King (1931), which was transferred to the genus Loricophrya by Matthes (1956). King (1931) discovered this species in a mixed culture of tap water and garden soil in Iowa City, USA. His population had only 3-4 corrugations in the posterior half of the lorica. However, this character is highly variable and thus can not be used to distinguish species. Furthermore, King (1931) did not compare his new taxon with P. lauterborni. Thecacineta caepula Penard 1920, a moss inhabitant, could be further synonym, viz. a poorly developed P. lauterborni without lorica corrugations. Jankowski (1978) erected the genus Heliotheka for this species, without new evidences however, while Matthes (1956) transferred it to Loricophrya. (ref. ID; 4861)
Systematic position
Sondheim's and my observations show that Paracineta lauterborni belongs to the suborder Podophryina because the swarmer is produced by pseudotransverse fission, as defined by Batisse (1994). Within the Podophryina, P. lauterborni fits into the family Paracinetidae Jankowski, 1978 and possibly to the genus Paracineta. However, Jankowski (1978) erected, again without new evidences, the genus Paraloricophrya for Sondheim's species, giving as sole distinguishing character "with stalk". Likewise, the combination with Loricophrya, as suggested by Matthes (1956, 1988), is uncertain because the type of swarmer production is unknown in the type species, L. parva (Schulz). All these genera are still poorly defined and it seems thus wise to keep the present species in the genus it was placed originally. (ref. ID; 4861)
Synonym
Podophrya limbata Maupas (ref. ID; 1618)
Descriptions
With or without gelatinous envelope; larva with many ciliated bands, contractile; on plants and animals in salt water. (ref. ID; 1618)
Measurements
20-50 um in diameter. (ref. ID; 1618)