Bicoronella
Bicoronella Foissner, 1995 (ref. ID; 4861 original paper)
[ref. ID; 4861]
Diagnosis; Pseudokeronopsidae (?) with transverse and caudal cirri and 2 arched rows of frontal cirri along anterior body margin. 2 frontoterminal cirri. (ref. ID; 4861)
Comparison with related genera; Bicoronella is similar to Tricoronella Blatterer & Foissner, 1988 (3 arched rows of frontal cirri), Pseudokeronopsis Borror & Wicklow, 1983 (without caudal cirri), Uroleptopsis Kahl, 1932 (without transverse cirri), Keronella Wiackowski, 1985 (many frontoterminal cirri forming a row, tailed midventral rows; now in subfamily Bakuellinae [Eigner, in press]), and Holosticha Wrzesniowski, 1877 (with 3-4 frontal cirri only). An almost unique feature of B. costaricana is the cirral row extending from the first frontal cirrus to the undulating membranes. Such a row is present also in Holosticha sylvatica Foissner, 1982, which, however, has 3 distinct frontal cirri only and is thus a typical Holosticha species (Berger & Foissner 1989). Whether Bicoronella belongs to the Pseudokeronopsidae or to another family (e.g. Holostichidae) is uncertain, because morphogenetic data are lacking and the Pseudokeronopsidae are still insufficiently defined (Wirnsberger 1987). Borror & Wicklow (1983) rejected the genus Uroleptopsis Kahl, 1932 because of the lack of transverse cirri in some marine clones of Pseudokeronopsis. However, no evidence was given, and more recent ontogenetic investigations prove the existence of populations with and without transverse cirri (Mihalowitsch & Wilbert 1990, Wirnsberger 1987, Wirnsberger et al. 1987). I thus re-establish Uroleptopsis Kahl, 1932 and combine Pseudokeronopsis ignea Mihailowitsch & Wilbert, 1990 with this genus: Uroleptopsis ignea (Mihailowitsch & Wilbert, 1990) nov. comb. (ref. ID; 4861)
Etymology; Composite of the Greek words "bi" (two) and "corone" (arch, latinized to "coronella"). Ferminine. (ref. ID; 4861)
Type species; Bicoronella costaricana (ref. ID; 4861)
- Bicoronella costaricana Foissner, 1995 (ref. ID; 4861 original paper)
Diagnosis
Size in vivo about 150-200x50-60 um. Cortical granules in rows, yellowish, 0.5-1.0 um in diameter. On average 65 macronuclear nodules, 53 adoral membranelles, 7 cirri in upper and 5 cirri in lower frontal row, 6 cirri in row extending from first frontal cirrus to buccal cavity, 19 midventral pairs terminating distinctly above transverse cirri, 10 transverse cirri, 4 caudal cirri, and 5 dorsal kineties. (ref. ID; 4861)
Descriptions
Slender, slightly sigmoidal and narrowed to posterior end, left margin distinctly convex, right slightly convex, straight or even slightly concave, both ends broadly rounded. Very flexible and dorsoventrally flatened up to 2:1. Macronuclear nodules and micronuclei ellipsoid, located mainly along body margins, Contractile vacuoles at left margin in mid-body, with two collecting canals extending anteriorly and posteriorly. Cells appear yellowish to yellowbrown at low magnification due to cortical granules and food inclusions. Feeds on coccal cyanobacteria, fungal spores, testate amoebae (Euglyphya rotunda) and possibly also on ciliates. Cirri 15-20 um long, marginal rows open at posterior end, gap occupied by caudal cirri. Distance between marginal cirri only slightly increasing from anterior to posterior end of rows. Midventral cirri closely spaced, form slightly sigmoid rows in median of cell, continue anteriorly as arched, distinctly separate rows of slightly enlarged frontal cirri having rhomboid and pentagonal bases. Frontoterminal cirri inconspicuous, closely underneath distal end of adoral zone of membranelles. Buccal cirrus near anterior end of paroral membrane. Transverse cirri slightly projecting above posterior end of body, minute, form J-shaped rows. Dorsal cilia about 5 um long, arranged in 5 (rarely 6) meridional rows almost as long as cell. Adoral zone of membranelles about 35% of body length, bases of largest membranelles about 10 um wide. Buccal cavity short and flat, but rather wide. Undulating membrane short as compared with length of adoral zone of membranelles, almost straight, intersect in posterior third. Pharyngeal fibres indistinct. (ref. ID; 4861)
Comparison with related species
Bicoronella costaricana is easily recognized in protargol slides by its unique frontal ciliature. In vivo it is easily confused with Holosticha sylvatica, Eschaneustyla bachytona and Keronella gracilis, which have a similar size, shape and cortical granulation. (ref. ID; 4861)
Etymology
Named after the country (Costa Rica) where it was discovered. (ref. ID; 4861)
Type location
Upper soil layer near the ranch house "La Cosona" in the Santa Rosa National Park, Costa Rica, W85 degrees 38', N10 degrees 50'. (ref. ID; 4861)