Notes on some tardigrades from southern Mexico with description of three new species
Author
Pilato, Giovanni
Author
Lisi, Oscar
text
Zootaxa
2006
1236
53
68
journal article
10.5281/zenodo.273448
7c65b6d3-2e82-4cb6-96cb-074f89a2382d
11755326
273448
Minibiotus continuus
sp.n.
(
Fig. 4
A–F)
Type
locality
Southern
Mexico
, Chiapas, Selva El Ocote.
|
Material examined
|
| Holotype (slide N. |
5090), |
2 paratypes |
and |
one |
egg |
from |
an undetermined |
moss |
sample |
| developing on rock. |
Species diagnosis
Cuticle smooth without pores; eye spots absent; pharyngeal bulb with apophyses, three granular macroplacoids and a small microplacoid; eggs with processes (21–22 around the circumference,
78–80 in
the hemisphere) similar to those of
M. intermedius
but all included in a continuous hyaline layer.
Description of the
holotype
Body length about
180 m
(
Fig. 4
A); colourless, cuticle smooth without pores, small dots present on the hind legs; eye spots absent. Mouth without peribuccal lamellae; buccal tube rigid, with two bends (
Fig. 4
A),
20.6 m
long and
1.3 m
wide (
pt
= 6.3); ventral lamina short (
7.4 m
,
pt
= 35.9); stylet supports inserted on the buccal tube at 56.1% of its length (
pt
= 56.1). Pharyngeal bulb (
18.9 m
x
16.6 m
) with apophyses, three granular macroplacoids and a small microplacoid. Each macroplacoid
1.9 m
long (
pt
= 9.2); microplacoid
0.9 m
long (
pt
= 4.4); entire placoid row
7.1 m
long (
pt
= 34.5); macroplacoid row
6.1 m
long (
pt
= 29.6).
Claws of
hufelandi
type
(
Fig. 4
B,C) 5.0 m long (
pt
= 24.3) on the second and third pairs of legs, anterior and posterior claws of the hind legs
5.8 m
(
pt
= 28.2) and
5.9 m
(
pt
= 28.6) long respectively. Accessory points on the main branches and smooth lunules present. No other cuticular thickenings seem to be present near the lunules on the legs.
Eggs, free laid, spherical, with processes similar to those of
M. intermedius
but all included in a continuous hyaline layer (
Fig. 4
D–F). Diameter
46.2 m
excluding the processes,
52.2 m
including them; 21–22 processes are present around the circumference,
78–80 in
the hemisphere; each process is
3.6 m
high, basal diameter
1.8 m
, diameter of the distal extremity
2.5–2.7 m
.
FIGURE 4.
Minibiotus continuus
sp. n.
A. Habitus and buccopharyngeal apparatus of the holotype (scale bar = 20 m). B. Claws of the third pair of legs of a paratype. C. Claws of the fourth pair of legs of a paratype. D. egg. E–F. Detail of the eggs where the hyaline layer is evident. Scale bar = 10 m.
Remarks
Minibiotus continuus
sp. n.
, due to some characteristics of the eggs, appears to be related to
Macrobiotus acontistus
De Barros, 1942
b (and that species, in our opinion, must be transferred to the genus
Minibiotus
)
, and to
Minibiotus taiti
. The
type
material of
M. acontistus
is lost but its description allows us to think that our specimens belong to a different species due to the absence of eye spots, the presence of microplacoid and to some differences in the eggs (diameter without processes
46.2 m
in
M. continuus
sp. n.
, up
59 m
in
M. acontistus
), with smaller processes (
3.6 m
high in
M. continuus
sp. n.
,
5 m
in
M. acontistus
).
The new species is also similar to
M. taiti
; but it differs from it in the following features: cuticular dots present only on the hind legs; stylet supports inserted on the buccal tube in a slightly more cephalic position (
pt
=
54.9–56.1 in
M. continuus
sp. n.
,
60–61 in
M. taiti
); shorter claws; and some characters of the eggs: smaller dimensions (diameter without processes about
46.2 m
in
M.continuus
sp. n.
,
54 m
in
M. taiti
), only 21–22 processes around the circumference (about
48 in
M. taiti
), only 78–80 processes in the hemisphere (about
160 in
M. taiti
).
Also
Macrobiotus spertii
Ramazzotti, 1957
has eggs with processes immersed in a hyaline membrane, but the dimensions of the animals and of the eggs and the characters of the processes clearly indicate that
Minibiotus continuus
sp. n.
is a different species.