Lepidotrachelophyllum
Lepidotrachelophyllum Nicholls & Lynn, 1984 (ref. ID; 4124 original paper)
[ref. ID; 4124]
Elongate, flattened, or leaf-like ciliates with some degree of flexibility; anterior 1/3-1/2 of body is contractile; ciliated on both somatic surfaces; in extended state, oral region narrow and flat; longitudinal kineties course from anterior to posterior pole; body surface covered by a "foam" composed of scales forming a layer several micrometers thick; contractile vacuole(s) at posterior end. (ref. ID; 4124)
Type species; Lepidotrachelophyllum fornicis (ref. ID; 4124)
- Lepidotrachelophyllum fornicis Nicholls & Lynn, 1984 (ref. ID; 4124 original paper)
See; Lepidotrachelophyllum lineare (Lepsi, 1960) Foissner, 1994 (ref. ID; 4613)
- Lepidotrachelophyllum lineare (Lepsi, 1960) Foissner, 1994 (ref. ID; 4613)
Syn; Lepidotrachelophyllum fornicis Nicholls & Lynn, 1984 (ref. ID; 4613); Trachelophyllum lineare Lepsi, 1960 (ref. ID; 4613)
See
Lepidotrachelophyllum lineare (Lepsi, 1960) Foissner, 1994 (ref. ID; 4613)
Diagnosis
Cells 40-350 um long; approx. 30 somatic kineties with two rows having clavate cilia in their anterior 1/3; narrow oral region 8-20 um wide when ciliate is extended; oral ciliature not distinctly different from adjacent somatic cilia; scale layer 3-6 um thick surrounding in the entire cell; scales of 2-5 by 4-8 um are composed of microfilamentous structures arranged in a tightly reticular baseplate and a loosely reticular superstructure; 1-2 macronuclei 20-33 um in length by 13-25 um in width; usually 2 micronuclei, approx. 3-4 um in diameter, associated with each macronucleus; a cold water stenotherm, only found during the late winter months. (ref. ID; 4124)
Descriptions
- Body shape: The ciliate is typically an elongate, flask-shaped cell, which is very flattened or leaf-like; however, there is some plasticity in the shape of living cells, which may vary from nearly spherical to fusiform and range in length from 40 to 350 um. The Chatton-Lwoff silver-impregnated specimens had a mean cell size of 282 by 58.5 um (180-466; SE 16.7; n=18; 35-86 um; SE 3.7; n=18) while the mean cell size of protargol-stained specimens was 228 by 56 um (160-293 um; SE 16.3; n=10; 31-82 um; SE 5.2; n=10). There are approximately 30 somatic kineties, which run long the body axis from the anterior to the posterior end. Two of the somatic kineties have clavate cilia in their anterior 1/3. The cilia are 10-15 um long. The organism swims at speeds of less than 100 um/sec, usually about 65 um/sec. (ref. ID; 4124)
- Scale layer:
- Light Microscopy. The scale layer appears as a band of "foam" around the cell. It remains intact despite continuous and active ciliary movement. The scale layer seems to impart some rigidly to the proximal 3-5 um of the cilium whose distal portion beats vigorously.
- Electron Microscopy. The layer of "foam" is seen to consist of thousands of scales. Some scales appear to be more perfectly formed than others; all are apparently variations on a common pattern. The shape of the scales is ovoid, from 4-8 um in length by 2-5 um in width. The scale is composed of microfilamentous structures that are arranged in a reticulated pattern; the patterning of filaments of the baseplate and the superstructure is different. The baseplate is ringed by circumferentially arranged microfilamentous components with surround a central region of filaments perforated by 0.1-0.2 um diameter holes; these baseplate perforations become smaller neat the ends of the scale. The superstructure has a much less regular reticulum whose 4-10 perforations are 0.3-0.7 um in diameter. Energy dispersive X-ray analysis showed that the scales were not primarily of silica or calcium but rather of an organic constitution. (ref. ID; 4124)
- Oral region: The oral region is placed at the extreme anterior pole of the cell. It can be slightly bulbous; however, a flattened dome or elevation has never been observed anterior to the corona of oral cilia. (ref. ID; 4124)
- Nuclei: There are usually two macronuclei whose mean length is 28.7 um (21-33 um; SE 0.7; n=21) and mean width is 20.1 um (13-25 um; SE 0.7; n=21) in protargol-stained specimens. Occasionally a ciliate may be observed with only one macronucleus but this is probably an individual that has recently divided. There are usually two, and rarely three, micronuclei about 3-4 um in diameter associated with each macronucleus. (ref. ID; 4124)
- Contractile vacuole: A very conspicuous contractile vacuole is located at the posterior pole. It is usually associated with 2-3 smaller ones, which appear to fuse with the main vacuole before it contracts to empty. (ref. ID; 4124)
Comments
There is no doubt that the scaled ciliate discovered in White Lake during late winter belongs to the Trachelophyllidae as presently diagnosed by Small & Lynn (1984). The flattened flask-shape of the cell, the number and organization of nuclei, and the position and structure of the oral region indicate that it is related to species in the genus Trachelophyllum; however, the presence of the sale layer is distinct enough, in our opinion, to diagnose a new genus in the family Trachelophyllidae, the genus Lepidotrachelophyllum n. g. from lepidos Gr. -scale, trachelos Gr. -neck and phyllon Gr. -leaf. The White Lake ciliates are placed in this genus as the type species Lepidotrachelophyllum fornicis n. sp. from fornix Gr. -arched, which refers to the arched or vaulted superstructure of the scales. In fact, there are two species of Trachelophyllum that have been described as having a "mucilage" or "gelationus" covering; these are Trachelophyllum vestitum Stokes, 1884 and Trachelophyllum sigmoides Kahl, 1926. Of the two, the White Lake ciliates resemble Trachelophyllum sigmoides: there is a slight asymmetry to the anterior end, there is no distinct oral dome; the "gelatinous" covering (= scale layer?) is thick and conspicuous moreover, of the two species, Kahl (1930) noted that T. sigmoides can also be found in winter. Recently Foissner (1983) has redescribed T. vestitum, illustrating the distinct oral dome, the symmetrical body shape, reniform macronuclei, and spindle-shaped micronuclei. Unlike T. sigmoides and T. vestitum, however, the White Lake ciliates have two rounded macronuclei, which were never observed to be joined by a funiculus, have at least two ovoid micronuclei associated with each macronucleus, were never observed to carry zoocholorellae, and were only collected in February over a period of five years. For these reasons, the White Lake ciliates are considered to belong to a different species and, because of the scale layer, to a different genus. When T. sigmoides or T. vestitum are examined using electron microscopy, the "gelatinous" covering might reveal scales of similar structure to those of Lepidotrachelophyllum. In this event, these two species should be transferred to the genus Lepidotrochelophyllum. Kahl (1930) also described one species in the genus Enchelys with a "gelatinous" (= scaly?) covering, Enchelys vestita Kahl, 1927. Thus among, the haptorids, this characteristic is probably a convergent feature whose adaptive significance, at present, is not known. (ref. ID; 4124)
Type locality
At the dam outflow of white Lake, Ontario, Canada at 44 degrees 50'N, 78 degrees 29'W. (ref. ID; 4124)
Deposited specimens
Holotype slide: The "type-specimen", USNM Slide no. 31205, has been deposited in the ciliate type-collection in the Invertebrate Zoology Division, Smithsonian Institution, Washington. D.C., U.S.A. (ref. ID; 4124)