The World of Protozoa, Rotifera, Nematoda and Oligochaeta
Favella
Favella Jorgensen, 1924 (ref. ID; 3607)
Order Heterotrichida Stein, 1867: Suborder Tintinnoinea Kofoid & Campbell, 1929: Family Cyttarocylidae Kofoid & Campbell, 1929: Subfamily Favellineae Kofoid & Campbell, 1929 (ref. ID; 3607)
Family Favellidae (ref. ID; 911)
[ref. ID; 3596]
Lorica bell-shaped, sometimes provided with a collar consisting of a number of spiral turns; oral rim entire or denticulate; bowl campanulate, rounded or convex conical in the aboral region; aboral horn usually present, often having wings, fins, or ridges; wall bi- or trilamellate, compact in an aboral horn, composed of a fine polygonal reticulation. (ref. ID; 3596)
Lorica inverted bell-shaped, 1.4-1.8 suboral diameters in length; oral margin entire with a slight brim; oral annular band usually single, single-layered; bowl cylindrical in the anterior half of the lorica, posteriorly convex conical (80-85 degrees) to a rounded end; wall hyaline, distinctly separated in the dilated band below the suboral annular ring and in the aboral end, but scarcely in the other part. (ref. ID; 3597)
Comments
The species differs from F. campanula (Schmidt) in the lack of an aboral horn and from F. composita Jorgensen in possessing fewer annular rings. (ref. ID; 3597)
Variety A: This species is characterised by the presence of a lorica with an anterior spiral lamina which is formed of many turns. The variety A has a short lorica which ends aborally with a solid pedicel. The pedicel is twisted with slight lateral expansions called "wings" which extend up to the bowl. The spiral lamina is formed of 7-9 turns. The lorica is about 1.1 oral diameters in length. (ref. ID; 4669)
Variety B: This variety possesses a fairly long and cylindrical lorica and, it differs from the variety A, in the nature of spiral lamina formed of 4-5 turns. The "wavy" nature of the turns is also an interesting feature The ratio of length to oral diameter is also about 1.1 as in variety A. (ref. ID; 4669)
Measurements
Variety A: Length 123.2 um (108.2-124.1 um); oral diameter 114.2 um (101.1-106.3 um). (ref. ID; 4669)
Variety B: Length 205.1 um (194.2-240.2 um); oral diameter 103.3 um (108.2-129.3 um). (ref. ID; 4669)
Lorica campanulate, 2.1 oral diameters in length; oral rim more or less irregular; bowl with a raised band just below the suboral ring, cylindrical in its upper 0.65; aboral region convex conical (80 degrees) to a stout horn; aboral horn having a few vertical striae on the surface, tapering (20 degrees) to a bluntly pointed tip, its length 0.15 of the total length; wall almost hyaline with a hardly visible reticulation, apparently separated in the suboral inflated part and scarcely in the following 0.15 of the total length. (ref. ID; 3597)
Comments
The species differs from F. azorica (Cleve) in the presence of an aboral horn. (ref. ID; 3597)
Measurements
Length 143; oral diameter 68 um. (ref. ID; 3597)
Favella campanula var. palaoensis Hada, 1938 (ref. ID; 3597 original paper)
Descriptions
Lorica goblet-shaped, 2.2-2.6 oral diameters in length; consisting of a suboral annulated part, a campanulate bowl, and an aboral horn; oral rim regularly serrated with numerous minute teeth; suboral part with one or two annular bands; bowl slightly expanding on its anterior margin, nearly cylindrical in its upper half, somewhat inflated and broadest at the portion of the posterior one-third, then aborally convex conical (85-100 degrees); aboral horn made of a tall cone with several marked oblique ridges, 0.19-0.24 of the total length, pointed at tip; wall entirely separated, with a very fine reticulation. (ref. ID; 3597)
Comments
The new variety differs from the typical form of F. campanula (Schmidt) in having a regular dentation and from F. fransiscana Kofoid & Campbell in the stout bowl and fine reticulation of the wall. (ref. ID; 3597)
[ref. ID; 7587]
Life cycle: During its cycle, Favella ehrebergii constructs three principal phenotypes of loricae which, until now, were considered different species and even different genera: the favella form sensu stricto, the coxliella form (Coxliella annulata) and the decipiens form (Coxliella decipiens). All three forms are cylindricalogival (average diameter ca. 104 um) and each can wear aboral horn of varied length. Their transparent homogeneous wall is made of only one layer of irregular alveoli, usually smaller near the oral aperture. Refringency gives the wall a trilamellate appearance: according to the forms, its structure is continuous, overlapped spiraled or sutured-spiraled. (ref. ID; 7587)
Favella form. The favella form has a smooth-walled continuous bowl which appears to be made of one piece (average length 219 um, max. 286 um, min. 137 um), and most often an aboral horn (average length 74 um. max. 174 um). It may have anteriorly a collar of the same diameter but spiral and generally overlapped in structure (average length 40 um) made of a band of varying heights (4.5-16.5 um)) with the ends tapered off in a point and rolled as a leiotropic helix with slightly overlapping turns, rarely sutured. (ref. ID; 7587)
Coxliella form. The coxliella form has an overlapped spiraled wall. It is entirely made of a band leiotropically wound as a spiral and then as a helix, the height of which decreases gradually and irregulary (from 16-24 um posteriorly to 5 um anteriorly) and tapers off in a point at its anterior end. Each spiral turn is slightly overlapped by the preceding turn. There is no aboral horn generally; the posterior end may be flattened, pointed or irregular and is infrequently open. The average overall length of the lorica is 224 um (max. 303 um, min. 83 um). (ref. ID; 7587)
Decipiens form. The decipiens form has a wall with a sutured-spiraled structure: the edges of the constitutive spiraled bands are not overlapped, as in the coxliella form, but jointed; hardly visible on the surface they can be seen on the longitudinal section of the wall due to transverse thickening between the alveoli at the point of suture. The aboral horn, always short (average length 30 um, max. 58 um) is straight or brent. Contrary to the other forms, the wall is always rough on the outside; the alveoli are indistinct and rather little swollen. The average overall length of the lorica is 225 um (max. 286 um, min. 141 um). (ref. ID; 7587)
Immediately following the division, the proter (anterior tomite or daughter cell) elaborates the favella form or the decipiens form, constructing, by itself, the bowl and the aboral horn in a few minutes. The opisthe (posterior tomite or daughter cells) keeps the original lorica. Later on in the trophic life, a spiraled collar can be added to the lorica, generally by the opisthe. The coxliella form also appears during interfissional periods, only if the lorica is abandoned. It results from a slow reconstruction, from 3 to 4 hours, by the naked trophont (ciliate during the nutrition period). (ref. ID; 7587)
Conjugation (in culture): The behavior is characteristic during the three phases: pre-conjugation, pairing and separation. As soon as a pair is constituted, one observes in the culture an increasing number of individuals in serch of a partner. Far from avoiding each other like during the trophic life, two individuals of Favella ehrenbergii, whose movements become slackened, are facing each other for about 5 mn; they bring their adoral membranelles nearer together and feel one another; then always face to face, they change their place a little keeping only a narrow contact on the edge of their peristomes. A wide cytoplasmic bridge is then established very quickly. Before the setting up of this bridge, when the pre-conjugants are separated by pipetting, a later rapprochement in a dish does not seem to allow their conjugation. Immediately after the cytoplasmic fusion, the conjugants pivot in order to put their loricae side by side in parallel, and they starts swimming. At the beginning, the membranelles beat slowly in only one conjugant. In the other one, they are motionless, then suddenly they start beatig together with the same rythm as those of the partner. The coordination of the movement of both crowns of adoral membranelles is remarkable. It allows the pair to behave like a single individual, with the helical forward swimming characteristic of the Tintinnina. But this swimming is mcuh slower than that of a trophont, for the beatings of the adoral ciliature are distinctly slower. It seems not to be interrupted for the ten hours of the conjugation as the conjugants of F. ehrenbergii were never observed retracted in their loricae. Considering their relative position, this contraction would oblige both partners to put their loricae in alignment by joining their anterior apertures. The conjugants seem not to feed. They do not contain large prey. Their cell volume is small, comparable with the one at the beginning of the trophic life. On the contraty, the ex-conjugants swim very fast and graze activity. (ref. ID; 7708)
Examined materials
Surface plankton samples were collected in the Bay of Villefranche-sur-Mer (France), from June to September and in February, with a net of 50 um or 30 um mesh, in the surface layer. (ref. ID; 7587)
F. ehrenbergii was collected in the surface layer, in the bay of Villefranche-sur-Mer (France), in May 1977; the seawater temperature varied from 16 degrees to 17.6 degrees C. (ref. ID; 7708)
Measurements
Its length varied from 150 to 450 um (mean 250 um). (ref. ID; 4577)
Lorica elongate goblet-shaped, 2.2-3.5 oral diameters in length; oral rim without a dentation; collar more or less flaring, made of a few spiral bands; bowl somewhat inflated below the nuchal constriction, its greatest transdiameter 1.00-1.06 oral diameters; aboral region gradually narrowing; aboral horn conical, usually elongate, 0.08-0.31 of the total length, ornamented with longitudinal striae on the surface, its tip bluntly pointed; wall completely separated in large specimens, but incompletely in small ones; reticulation irregular, rarely disappearing as seen in ovate fenestrae in the anterior dilated region. (ref. ID; 3596)
Lorica tall goblet-shaped, 3.2-3.7 oral diameters in length; oral rim entire, but not quite smooth; oral region a low funnel of 20-35 degrees with 1-2 spiral turns, its length 0.11 of the oral diameter; bowl bell-shaped, slightly expanding below the nuchal constriction, widest near the posterior 0.4 of the bowl, contracting aborally into a conical aboral end of 60-75 degrees; aboral horn nearly circular in cross section, more or less longitudinally rugose on the surface, conical (7-13 degrees), 0.24-0.30 of the total length in length, tip bluntly pointed; wall finely prismatic, more in the oral region than in the bowl. (ref. ID; 3607)
Comments
As a seasonal variation the lorica of summer specimens (260 um in average length) are observed to be generally larger than those of autumn ones (170 um in average length). The aboral region is variable in shape and the aboral horn in length and form. The horn is sometimes short and stout, but has neither wings nor ridges as in other species of Favella. The wall is entirely separated in the bowl of large specimens, but only in the upper part of the bowl of smaller ones. Some specimens from outside Akkeshi Bay have ovoid clear areas in the anterior region of the lorica. The species differs from F. ehrenbergi (Claparede & Lachmann) in possession of a suboral inflation and of striae on the aboral horn instead of wings, and from F. panamensis Kofoid & Campbell in the lack of fins on the aboral horn. (ref. ID; 3596)
Differs from Favella ehrenbergii (Claparede & Lachmann) in lack of fins apendicular to the aboral horn, from P. franciscana Kofoid & Campbell in having the entire oral rim instead of oral denticulation, and from F. panamensis Kofoid & Campbell in size, in proportions, and in absence of wings of the aboral horn. (ref. ID; 3607)
Type locality
The species is known from Taraika Bay in the Sea of Okhotsk. (ref. ID; 3596)
Measurements
Length 148-288; oral diameter 68-90; height of the collar 5-8; length of the aboral horn 12-90 um. (ref. ID; 3596)
Length 283 (260-314); oral diameter 83 (80-86) um. (ref. ID; 3607)