Annotated list of Tardigrada records from Ukraine with the description of three new species
Author
Pilato, Giovanni
Author
Kiosya, Yevgen
Author
Lisi, Oscar
Author
Inshina, Valentina
Author
Biserov, Vladimir
text
Zootaxa
2011
3123
1
31
journal article
45831
10.5281/zenodo.279398
34ce6298-fc68-42cb-8075-40fb85ddf824
1175-5326
279398
Hypsibius pallidoides
sp. nov.
(
Fig. 7
)
Material examined.
Kherson Oblast, Ivano-Rybalchansky district of Chernomorsky biosphere reserve (46°27ʹ25ʺN, 32°8ʹ56ʺE), collector D.A. Korolesova, moss on wood,
June 2008
:
holotype
, seven
paratypes
and additional
27 specimens
and nine exuvia.
FIGURE 7.
A–D,
Hypsibius pallidoides
sp. nov
.
: A, Bucco-pharyngeal apparatus of the holotype (slide No. 5430) (the arrow indicates the very small septulum). B, Bucco-pharyngeal apparatus of a paratype (slide No. 5430) (the arrow indicates the very small septulum). C, D, Claws of the second pair of legs of the holotype. E,
Hypsibius pallidus
: Bucco-pharyngal apparatus (slide No.1251). (Scale bars = 10 µm).
Type
repository.
Holotype
, seven
paratypes
and three exuvia (slide No.5430) are deposited in the collection of Binda & Pilato (Museum of the Department of Animal Biology “Marcello La Greca”, University of Catania,
Italy
). Other specimens are deposited in the Kiosya's collection (School of Biology,
V.N.
Karazin Kharkiv National University,
Ukraine
).
Specific diagnosis.
Eye spots present; cuticle smooth; buccal armature without teeth; buccal tube very narrow; pharyngeal bulb with two macroplacoids and a very small, dot-shaped, septulum; claws similar to
Hypsibius pallidus
(i.e. the main branches of the external claws were inserted on the secondary branches well above the claw base); accessory points present; lunules absent; no cuticular bar on the first three pairs of legs; the cuticular bar between the claws on the hind legs seemed to be absent, but this character needs to be confirmed. Smooth eggs laid in the exuvia.
Description of the
holotype
.
Body length 252 µm; colorless, cuticle smooth without cuticular pores or dots. Eye spots present. Bucco-pharyngeal apparatus of
Hypsibius
type
(
Fig. 7A, B
). Mouth subterminal without peribuccal lamellae; small buccal cavity without rings of teeth. Narrow, rigid buccal tube, without ventral lamina, 22.3 µm long and 1.5 µm wide externally (
pt
= 6.7); stylet supports inserted on the buccal tube at 55.5 % of its length (
pt
= 55.5). Pharyngeal bulb (20.0 µm × 18.2 µm) with apophyses, two macroplacoids and a very small, dotshaped septulum (
Fig. 7A, B
, arrow). First macroplacoid 3.8 µm long (
pt
=17.0), second 2.6 µm (
pt
= 11.7); macroplacoid row length 6.9 µm (
pt
= 30.9).
Claws of the
Hypsibius
type
, well developed; the main branches of the external claws were inserted on the secondary branches well above the claw base (
Fig. 7C, D
) as in
Hypsibius pallidus
. Main brancheses of all claws with very thin accessory points. External and internal claws on the second and third pairs of legs 12.7 µm (
pt
= 57.0) and 7.6 µm long (
pt
= 34.1) respectively; claw orientation on the hind legs did not allow correct measurements, but in
Table 4
the measurements of two
paratypes
are shown. Lunules absent; a cuticular bar between the claws of the hind legs seemed to be absent, but this character needs to be confirmed; no cuticular bar on the first three pairs of legs.
Decription of the eggs.
Smooth eggs laid in the exuvia.
Remarks.
The
paratypes
were similar to the
holotype
in qualitative and metric characters. The measurements of three specimens are reported in
Table 4
.
Etymology.
The specific name
pallidoides
indicates that this new species closely resembles
Hypsibius pallidus
.
Differential diagnosis.
Hypsibius pallidoides
sp. nov
.
was very similar to
H. pallidus
, which lacks any microplacoid or septulum, and had higher values of
pt
index for the macroplacoids (
Table 4
;
Figs. 7A–B and 7
E). Five species of
Hypsibius
were known to have smooth cuticle, two macroplacoids and septulum:
H. dujardini
,
H. iskandarovi
,
H. septulatus
,
H. heardensis
Miller, McInnes & Bergstrom, 2005
, and
H. seychellensis
.
H. pallidoides
sp. nov
.
differed from all in having external claws of
Hypsibius pallidus
-
type
and in having smaller, dot-shaped, septulum. Other differences include:
the lack of eye spots and presence of a pseudoseptulum in
H. iskandarovi
(
Figs. 7 A, B
and
8 A
); the stylet supports inserted on the buccal tube in a more cephalic position (
pt
=
54.2–55.5 in
H
.
pallidoides
sp. nov
.
, more than
58 in
H. iskandarovi
); shorter claws (
pt
index relative to the posterior claws of the hind legs:
68.6–72.1 in
Hypsibius pallidoides
sp. nov
.
,
75.4–95.3 in
H. iskandarovi
according to
Tumanov, 1997
); presence of lunules (
Figs. 7C, D
and
8B
) and cuticular bar on the first three pairs of legs for
H. iskandarovi
, all absent from the new species.
Cuticular undulations in
H. septulatus
were lacking in
H
.
pallidoides
sp. nov
, the buccal tube was slightly narrower and the stylet supports inserted on the buccal tube in a more cephalic position (
pt
=
54.2–55.5 in
H
.
pallidoides
sp. nov
,
64.5 in
H. septulatus
) (
Table 4
;
Figs. 7A, B
and
8
C); septulum much smaller, claws were slightly shorter (
Table 4
) and absence of cuticular bar on the legs (
Figs 7C, D
and
8
D).
H. heardensis
lacked eye spots, present in the new species, and possessed cuticular bar on the legs, which were absent from
H. pallidoides
sp. nov
.
The stylet supports of
H. pallidoides
sp. nov
.
were inserted on the buccal tube in a more cephalic position than for
H. seychellensis
(
pt
=
54.2–55.5 in
H
.
pallidoides
sp. nov.
,
62.3–63.7 in
H. seychellensis
) and the placoids were slightly shorter.
The buccal tube of
H. dujardini
gradually increased in width towards the posterior end, while the buccal tube of
H
.
pallidoides
sp. nov
had a uniform width (
Figs. 7A
and
9A
); the stylet supports were inserted on the buccal tube in a more cephalic position (
pt
=
54.2–55.5 in
H
.
pallidoides
sp. nov
, about
64 in
H. dujardini
); and the cuticular bar between the claws on the hind legs was present in
H. dujardini
, but apparently absent in the new species.
Hypsibius allisoni
had a very small microplacoid (
Fig. 9
C), not the septulum present in
H. pallidoides
sp. nov
.
, though it can be difficult to distinguish the difference between a microplacoid and a septulum. We therefore stress that the claw shape of
Hypsibius pallidoides
sp. nov
.
was very different from
H. allisoni
, as the main branch was inserted on the secondary branch in a more distal position (
Figs. 7C, D
and
9
D).