Updating the phylogeny and taxonomy of pleurostomatid ciliates (Protista: Ciliophora) with establishment of a new family, a new genus and two new species
Author
Zhang, Gongaote
Author
Zhao, Yan
Author
Chi, Yong
Author
Warren, Alan
Author
Pan, Hongbo
Author
Song, Weibo
text
Zoological Journal of the Linnean Society
2022
2022-04-27
196
1
105
123
http://dx.doi.org/10.1093/zoolinnean/zlac028
journal article
10.1093/zoolinnean/zlac028
28e9da47-c1d8-45ab-8cae-5b229087fa86
0024-4082
7035078
91E1877D-99F9-42EF-B211-23C0F7F0D539
LOXOPHYLLUM APOCHLORELLIGERUM
SP. NOV
.
(
FIGS 4
,
5
;
TABLE 1
)
Zoobank registration:
urn: lsid: zoobank. org:act:
32A46325-B72C-4B1D-A5AA-44145403DBB3
Table 1.
Morphometric characteristics of Chinese populations of
Loxophyllum apochlorelligerum
sp. nov.
(upper line) and
Paralitonotus foissneri
sp. nov.
(lower line) based on silver proteinate-stained specimens
| Characters |
Minimum |
Maximum |
Mean |
Median |
SD |
CV |
N
|
| Body length (µm) |
163 |
285 |
212.0 |
211 |
30.76 |
14.5 |
25 |
| 79 |
150 |
119.5 |
121 |
19.34 |
16.2 |
17 |
| Body width (µm) |
30 |
81 |
52.3 |
50 |
11.14 |
21.3 |
25 |
| 13 |
30 |
23.5 |
23 |
5.39 |
22.9 |
17 |
| Number of right somatic kinetiesa |
12 |
14 |
12.8 |
13 |
0.60 |
4.7 |
25 |
| 13 |
15 |
14.1 |
14 |
0.56 |
4.0 |
17 |
| Number of left somatic kinetiesb |
7 |
9 |
7.8 |
8 |
0.83 |
10.7 |
25 |
| 6 |
7 |
6.2 |
6 |
0.44 |
7.0 |
17 |
| Number of dorsal brush dikinetids |
40 |
56 |
47.7 |
48 |
4.77 |
10.0 |
25 |
| 29 |
37 |
32.6 |
33 |
2.99 |
9.2 |
7 |
| Number of macronuclear nodulesc |
1 |
2 |
1.9 |
2 |
0.33 |
17.6 |
25 |
| 1 |
2 |
2.0 |
2 |
0.24 |
12.5 |
17 |
| Macronuclear nodule length (µm) |
18 |
63 |
30.4 |
29 |
8.32 |
27.4 |
47 |
| 9 |
30 |
16.4 |
16 |
3.75 |
22.8 |
33 |
| Macronuclear nodule width (µm) |
12 |
36 |
20.1 |
19 |
5.26 |
26.2 |
47 |
| 4 |
9 |
6.4 |
6 |
1.27 |
20.0 |
33 |
aPerioral
kinety 2 or perioral kineties 2–3 were included.
bPerioral
kinety 1 and dorsal brush kinety were included.
cOut
of 25 individuals of
Loxophyllum apochlorelligerum
sp. nov.
only three had a single macronuclear nodule; and out of 17 individuals of
Paralitonotus foissneri
sp. nov.
only one had a single macronuclear nodule.
Abbreviations: CV, coefficient of variation (as a percentage); mean, arithmetic mean;
N
, number of specimens; SD, standard deviation.
Diagnosis:
Body lanceolate, about 170 – 280 µm × 35–50 µm
in vivo
; seven to nine left and 12–14 right somatic kineties; extrusomes clavate, distributed along entire cell margin; three to five inconspicuous dorsal warts located at anterior one-third of body; single subterminal contractile vacuole; two ovoidal macronuclear nodules and one micronucleus; freshwater habitat.
Type material:
A silver proteinate slide with the
holotype
specimen circled by ink and another two silver proteinate slides with
paratype
specimens deposited in the Laboratory of Protozoa, Ocean University of
China
, with registration numbers
ZGAT2020051801-1
(
holotype
)
,
ZGAT2020051801-2
and
ZGAT2020051801-3
.
Type
locality and ecological features:
A boggy area in
Weishan Lake
(
34°45′59.56″N
,
117°09′22.65″E
),
Ji’ning
,
China
.
Water
temperature 21 °C and pH 8.30
.
Etymology:
Composite of the Greek adjective αΠό- (from) and the species-group name
chlorelligerum
(‘bearing chlorellae’, a green alga), indicating a ciliate similar to
Loxophyllum chlorelligerum
Vuxanovici, 1959
.
SSU rDNA sequence:
The SSU rDNA sequence of
Lo. apochlorelligerum
sp. nov.
has been deposited in the GenBank database, with length 1531 bp, G+C content 42.26% and accession number
MW414675
. The SSU rDNA gene sequence similarity between
Lo. apochlorelligerum
sp. nov.
and its congeners ranges from 0.958 to 0.978 (
Fig. 8
).
Description:
Body lanceolate, slightly contractile, with a beak-like anterior end and a pointed posterior end. Cell size about 170–280 µm × 35–50 µm
in vivo
when fully extended. Neck region inconspicuous, occupying 25% of cell length, often with several inconspicuous dorsal warts (
Fig. 4A
, arrows). Cell typically with a thin, well-defined hyaline fringe (
Fig. 5A, D, G
). Right side densely ciliated; left side somewhat vaulted and sparsely ciliated. Two macronuclear nodules, elliptical in outline, about 15–23 µm × 10–15 µm
in vivo
, centrally located (
Figs 4D, E, H
,
5B, E, I
;
Table 1
). Micronucleus positioned between macronuclear nodules (
Figs 4H
,
5I
). Contractile vacuole subterminally located (
Figs 4A, D, F
,
5A, B, G
), ~15–20 µm in diameter, pulsating about every 30 s. Extrusomes clavate, straight or slightly curved, ~5–7 µm long, distributed along entire cell margin and often clustered in anterior portion of dorsal margin to form three to fie warts (
Figs 4A, D, J
,
5C, F
). Cortical granules tiny (<0.3 µm) and densely distributed between ciliary rows (
Figs 4I
,
5H
). Cytoplasm colourless or greyish, with numerous densely packed food vacuoles (~4–7 µm in diameter) that render main body region opaque (
Figs 4A, F
,
5A, B, D, G
). Locomotion typically by slowly gliding on substrate, sometimes by swimming while rotating about longitudinal body axis.
Figure 4.
Loxophyllum apochlorelligerum
sp. nov.
in life (A, D–F, H–J) and after silver proteinate staining (B, C, G). A, left view of a typical individual; arrows point to dorsal warts. B, C, ciliary pattern of left (B) and right (C) sides. D, distribution of extrusomes; the arrow marks the contractile vacuole. E, shape variants in the same individual. F, specimens from the original population of
Loxophyllum chlorelligerum
, redrawn from
Vuxanovici (1959)
. G, anterior portion of left side. H, nuclear apparatus. I, cortical granules. J, extrusomes. Abbreviations: DB, dorsal brush; Ex, extrusomes; Ma, macronucleus; Mi, micronucleus; PK1, perioral kinety 1; PK2, perioral kinety 2; PK3, perioral kinety 3. Scale bars: 75 µm in A–C; 40 µm in D, E; 2 µm in J.
Ciliary pattern as shown in
Figure 4B, C, G
. There are 12–14 right somatic kineties (including PK2 and PK3), each consisting of monokinetids and terminating anteriorly along PK3 (
Figs 4C
,
5J
;
Table 1
). Left side sparsely ciliated, with seven to nine (average eight) left somatic kineties (including PK1;
Figs 4B
,
5L, M
;
Table 1
). Dorsal brush kinety consisting of regularly spaced dikinetids in anterior half of cell length and continuing posteriorly as monokinetids (
Fig. 4B, G
).
Three perioral kineties around oral slit. Perioral kinety 1 (PK1) consisting of densely spaced dikinetids in anterior half and continuing posteriorly as a row of monokinetids (
Fig. 4B, G
). Perioral kinety 2 (PK2) consisting of densely spaced dikinetids in anterior half and continuing posteriorly as a row of monokinetids (
Fig. 4C, G
). Perioral kinety 3 (PK3) composed of densely spaced monokinetids (
Fig. 4C, G
).