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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Discomorphella

Discomorphella Corliss, 1960 (ref. ID; 2014)

Class Polyhymenophora: Subclass Spirotricha: Order Odontostomatida (ref. ID; 2014)

Synonym; Discomorpha Levander, 1894 (ref. ID; 2014)

[ref. ID; 2014]
Discoid body with wide, clear dorsal keel which terminates anteriorly in a long, narrow spine. Body covered in pellicular armour with 2 other spines on right surface, 1 spine posterior the other anterior. The peristome and AZM, unlike in other odontostomes, can be seen from both sides of the body. Somatic cilia reduced to several rows which are located in the posterior body half. Perizonal complex with 5 upper single rows which are located on a hoop-like structure that has a corrugated surface. Below the hoop are 2 double rows of cirri. There are 3 to 5 thick posterior cirri. Single macronucleus and micronucleus. Sapropelic. Most easily confused with Saprodinium in which genus there are both anterior and posterior somatic cilia present. Single species genus.
Quote; Colin R. Curds, Michael A. Gates and David McL. Roberts "British and other freshwater ciliated protozoa Part II Ciliophora: Oligohymenophora and Polyhymenophora" Cambridge University Press, 1983 (ref. ID; 2014)
  1. Discomorphella pectinata (Kahl) (ref. ID; 1308)
  2. Discomorphella pectinata Levander (ref. ID; 1618) or (Levander, 1894) Corliss, 1960 (ref. ID; 313, 4610), (Levander) Corliss, 1960 (ref. ID; 1219, 1629)
    Syn; Discomorpha lauterborni Wetzel, 1928 (ref. ID; 4610); Discomorpha pectinata Levander, 1894 (ref. ID; 4610)

Discomorphella pectinata Levander (ref. ID; 1618) or (Levander, 1894) Corliss, 1960 (ref. ID; 313, 4610), (Levander) Corliss, 1960 (ref. ID; 1219, 1629)

Synonym

Discomorpha lauterborni Wetzel, 1928 (ref. ID; 4610); Discomorpha pectinata Levander, 1894 (ref. ID; 4610)

Diagnosis

Discoid rigid body, laterally compressed, 60 um. Long cortical point extends the dorsal ridge anteriorly. Two strong spines extend from the right side. The thin ventral surface carries the peristomal region, located between an anterior epistomial fringe that is fragmented in two parts and two groups of posterior ventral kineties. The oral infraciliature includes perioral kineties, endoral and paraoral kineties, and adoral membranelles. Somatic kineties, unequally distributed on the two sides, partially non-ciliated and randomly positioned locally. Three long cirri at the base and to the left of the dorsal ridge. One oblong to spheroid macronucleus (10 um) flanked by a micronucleus (2 um). Freshwater, more or less saprobic. Containing endosymbiotic bacteria. (ref. ID; 313)

Descriptions

D. pectinata has an epistomial fringe formed by the anterior intensification of at least five somatic kineties that encircle the oral zone on the right side. This arrangement, discovered by Wetzel (1928) and then observed by Klein (1930), seems to represent a structure that appears virtually autonomous from the inferior parts of the kineties from which it apparently arises. This fringe, of which one part is curiously isolated on the left side of the body, thus appears separated from the rest of somatic ciliature from which it probably derived. This apparent distinctiveness is even more remarkable if one considers the ciliated kinetosomes that compose the notched brow, forming a kind of visor that surrounds the anterior ventral face of the ciliate. These kinetosomes are organized in a successive series of rows perpendicular to the axis of the fringe and give rise to long cilia that extend down to the pristomial depression. This is similar to what one observes in the same region of the body in species in the Metopidae and Caenomorphidae and, in a less conspicuous fashion, in other odontostomes like Epalxella and Saprodinium. The peristomal depression is outlined anteriorly by two sigmoid perioral kineties, below and at some distance from the epistomial fringe. They extend to the right into the oral cavity to the median level, almost joining but not touching two endoral kineties, which fold back on themselves in a horseshoe-like arrangement. One dozen short adoral membranelles are situated near the cytostome, not far from a paroral kinety that is located on the right wall of the buccal infundibulum. These oral structures are difficult to observe, most often being obscured by the arrangement of the peristomial lips of which the right lip shows a long pointed extension and the left lip forms a kind of lateral roof. Four straight kineties with long cilia extend posterior to the peristomal region, from one side to the other across the quite narrow ventral surface of the ciliate. Two of these are quite shortened and extend along the left side and two are longer and extend along the right side. There is a complex infraciliature in D. pectinata that has not been described previously (Jankowski 1964; Lauternborn 1908, 1916; Levander 1894; Wetzel 1928). It is possible that these previous descriptions have presented simplified descriptions because not all somatic kinetosomes appear to the ciliated and are therefore not observed in vivo. There are seven conspicuous somatic kineties on the right side, one of which sometimes extends onto the other side, and four ventral somatic kineties as described above. There are apparently only two left somatic kineties that are extremely difficult to observe: one long arched kinety extends along the dorsal edge while the other shorter one courses below. Many kinetosomes are seemingly revealed without visible cilia by accumulation of stain in a small argentophilic cupule. Other kinetosomes are erratically positioned, apparently rupturing the line of a kinety or seemingly randomly distributed. It is thus impossible to definitively establish the exact number of somatic kineties. This relatively aberrant infraciliature is augmented posteriorly by three long cirri, placed at the end of one of the left somatic kineties, near the dorsal ridge. The cirri cannot be confused with the three long, strong, and semi-rigid spines that ornament the right side of the body: one of these extends away from the ciliate like the point of a helmet to which this species can be compared. It is this assemblage of denticles, the complex infraciliary structures on its elaborate morphology, and also the fact that the kinetosome is not always ciliated, which constitute without doubt the uniqueness of this curious ciliate. (ref. ID; 313)
Sapropelic. (ref. ID; 1618)

Measurements

70-90 um long. (ref. ID; 1618)