Redescriptions of three Milnesium Doyère, 1840 taxa (Tardigrada: Eutardigrada: Milnesiidae), including the nominal species for the genus
Author
Michalczyk, Łukasz
Author
Wełnicz, Weronika
Author
Frohme, Marcus
Author
Kaczmarek, Łukasz
text
Zootaxa
2012
3154
1
20
journal article
45702
10.5281/zenodo.214356
2ccb32a4-9476-4a35-9231-e9849f5ed473
1175-5326
214356
Milnesium granulatum
Ramazzotti, 1962
, bona species
(
Figs 7–11
,
Table 2
)
Material examined.
One
paratype
, female, slide labelled as follows: “Tipo 145. 1
H. baumanni
,
1
M.
tardigradum granulatum Ramazzotti; Fray Jorge (
Cile
) a m 620,
22.5.62
, Lichene su parmo (Polivinil).”
Description (measurements in
Table 2
).
Body colour unknown, eyes present according to the original description (
Ramazzotti 1962
), but now are no longer visible (
Fig. 7
). Dorso-lateral cuticle or only caudo-dorsal cuticle covered with a reticular design (diameter of polygons 0.5–1.5 μm) (
Fig. 8
). The design better developed on the caudal cuticle. Ventral cuticle smooth. Granulation or pores in cuticle absent. Two lateral and six peribuccal papillae present(ventral papilla smaller than other papillae).
Buccal apparatus of the
Milnesium
type
(
Fig. 9
). Six peribuccal lamellae around the mouth opening present. Buccal tube slightly funnel-shaped, wider anteriorly (posterior diameter 87% of the anterior diameter). Pharyngeal bulb elongated, pear-shaped and without placoids or septulum.
FIGURES 7–9.
Milnesium granulatum
Ramazzotti, 1962
.
7
—habitus (dorso-ventral view, paratype);
8
—dorso-caudal cuticle (paratype);
9
—buccal tube (dorso-ventral section, paratype). [All PCM].
FIGURES 10–11.
Milnesium granulatum
Ramazzotti, 1962
.
10
—claws III (paratype);
11
—claws IV (paratype). [All PCM].
Claws of the
Milnesium
type
, slender (
Figs 10–11
). Primary branches on all legs with small, but distinct accessory points detaching from the branch near its end. Secondary branches with rounded basal thickenings. All secondary branches on all legs with three points (i.e. claw configuration: [3-3]-[3-3]). Single, long transversal, cuticular bars under claws I–III present (
Fig. 10
).
Although eggs were not described by
Ramazzotti (1962)
, we should probably expect them to be oval, smooth and deposited in exuvium as in all other known
Milnesium
species.
Remarks.
Maucci (
1973–74
)
reported
M. tardigradum granulatum
also from the Trieste Kras, but we have not had an occasion to examine those animals. However, given the
locus typicus
of
M. granulatum
lies on a different continent and in a different zoogeographical region, we hypothesise that Maucci could have found a different species of the
Milnesium granulatum
group. Until the record is re-examined, we suggest this report should be considered dubious.
Locus typicus.
Coquimbo Region, Bosque de Fray Jorge National Park, Ovalle,
ca.
420 km
to the North from Santiago de
Chile
,
ca.
30°40'S
and
71°40'W
,
ca.
600 m
asl, temperate hygrophilous forest surrounded by steppe, mosses and lichens growing on shrubs.
Distribution.
Currently confirmed is only the
type
locality in
Chile
(but see also
Remarks
above).
Etymology.
Giuseppe Ramazzotti named the species ‘
granulatum
’ most likely because he interpreted the reticular design on the cuticle as granulation. In fact, ‘granules’ are shallow depression in the shape of rounded polygons (see
Fig. 8
).
Type
depositories.
The
type
material is preserved at the Natural History Museum of Verona,
Italy
.
Differential diagnosis.
Apart from
M. granulatum
there are four other described
Milnesium
species with sculptured cuticle (see
Table 1
).
M. granulatum
differs specifically from:
M. alabamae
Wallendorf & Miller, 2009
by having accessory points on the primary branches.
M. katarzynae
Kaczmarek, Michalczyk & Beasley, 2004
by a different claw configuration ([3-3]-[3-3] in
M. granulatum
and [2-2]-[2-2] in
M. katarzynae
), a wider buccal tube (
pt ca. 39
% in
M. granulatum
and
pt ca. 21– 26%
in
M. katarzynae
) and stylet supports inserted in more anterior position (
pt ca. 66%
in
M. granulatum
and
pt. ca. 73–78%
in
M. katarzynae
).
M. krzysztofi
Kaczmarek & Michalczyk, 2007
by a different claw configuration ([3-3]-[3-3] in
M. granulatum
and [2-3]-[3-2] in
M. krzysztofi
).
M. reticulatum
Pilato, Binda & Lisi, 2002
by the absence of gibbosities, having six peribuccal lamellae (four in
M. reticulatum
) and a different claw configuration ([3-3]-[3-3] in
M. granulatum
and [2-3]-[3-2] in
M. reticulatum
).