Milnesium validum,

Lisi, Oscar, 2017, Two new species of Eutardigrada from Victoria Land, Antarctica, Zootaxa 4317 (3), pp. 541-558: 548-554

publication ID

https://doi.org/10.11646/zootaxa.4317.3.6

publication LSID

lsid:zoobank.org:pub:E5Fc4877-9878-4460-9Db7-335649B62271

persistent identifier

http://treatment.plazi.org/id/7E4D8B77-FFE9-3125-609F-FDAFFE27FED2

treatment provided by

Plazi

scientific name

Milnesium validum
status

sp. nov.

Milnesium validum  sp. nov.

Fig. 6View FIGURE 6, Table 2

Type locality. Antarctica: Shore of Carezza Lake , 71° 43’ S 164° 03’E.GoogleMaps 

Material examined. (collected by Prof. Salvatore Motta between 1990.12.15 and 1991.1.12): shore of Carezza Lake: the holotype (slide No. 4035) and two paratypes (slides nos. 4036–4037) in a moss sample; Lamplugh Island (75° 34’S 162° 55’E): two paratypes (slides Nos. 4038 and 4047) in a moss sample, together with Acutuncus antarcticus  ; Edmonson Point (74° 21'S, 165° 10'E): two exuviae (slide No. 4039 with 2 eggs, and 5777 with 9 eggs) in a moss sample, together with Acutuncus antarcticus  .

Type repository. Holotype and paratypes are preserved in the collection of Binda & Pilato in the Department of Biological , Geological and Environmental Sciences ( Section of Animal Biology “ Marcello La Greca ” of the University of Catania, Italy). 

Specific diagnosis. Body colourless; cuticle smooth; eye spots present; six peribuccal and two lateral papillae present; mouth terminal with six triangular peribuccal lamellae with basal stripes; cylindrical buccal tube not very wide; stylet supports inserted on the buccal tube at 61.1–64.8% of its length; claws of the Milnesium  type with a [3- 3]-[3-3] configuration; primary branches with thin accessory points; secondary claws stout, with distal portion clearly wider than the basal portion; each with a rounded basal thickening (lunule); a long cuticular bar present under claws I –III.

Description of the holotype. Body 482 µm long; colourless; cuticle smooth without pseudopores, reticulum, tubercles or gibbosities; eyes present; six cephalic and two lateral papillae present; bucco-pharyngeal apparatus of Milnesium  type ( Fig. 6View FIGURE 6 A) (buccal tube rigid without ventral lamina; apophyses for the insertion of the stylet muscles in the shape of very short and flat ridges symmetrical with respect to the frontal plane and without caudal processes; pharyngeal bulb without apophyses, placoids or septulum). Mouth terminal with six triangular peribuccal lamellae with basal stripes; buccal tube cylindrical 55.6 µm long, not very wide (16.6 µm externally at the level of the stylet supports insertion point, pt index value = 29.9); stylet supports inserted on the buccal tube at 62.0% of its length (pt = 62.0); stylet furca with well-developed branches ( Fig. 6View FIGURE 6 A); pharyngeal bulb pear-shaped.

Claws of the Milnesium  type ( Figs. 6View FIGURE 6 B –D); secondary claws stout, with the distal portion clearly wider than the basal portion ( Figs. 6View FIGURE 6 B –D) and with three points, configuration [3-3]-[3-3]; the second point (point b, according to the terminology used by Binda & Pilato 1990) is clearly longer and wider than the other two, particularly at the distal point ( Figs. 6View FIGURE 6 B –D). Primary claws on legs I, 20.0 µm long (pt = 36.0) and secondary claw, 14.5 (pt = 26.1); the percent ratio secondary/primary claw is 72.5; primary claws on legs II, 20.7 µm long (pt = 37.2); secondary claw II, 15.0 µm long (pt = 27.0); the secondary/primary claw percent ratio is 72.5; primary claws on legs III, 22.0 µm long (pt = 39.6), secondary claw III could not be measured; primary claws on legs IV, 26.9 µm long (pt = 48.4), secondary claws on legs IV, 16.9 µm (pt = 30.4); the secondary/primary claw percent ratio is 62.8.

Primary claws with thin accessory points; each secondary claw base with rounded basal thickening (lunule) ( Fig. 6View FIGURE 6 D, arrow); a long cuticular bar is present under the claws I –III ( Fig. 6View FIGURE 6 B, arrow).

Eggs smooth laid in the exuvium (we found an exuvium with two eggs and another with nine eggs).

Remarks: The paratypes are similar to the holotype in both qualitative and quantitative characters ( Table 2). Together with Milnesium validum  sp. nov. we found specimens of Acutuncus antarcticus  .

Etymology: the specific name validum  (validus = vigorous) refers to the robustness of the secondary claws.

Milnesium validum  sp. nov Differential diagnosis: Within the genus Milnesium  twelve species with smooth cuticle, six peribuccal lamellae and [3-3]-[3-3] claw configuration are known: Milnesium brachyungue Binda & Pilato, 1990  ; Milnesium eurystomum Maucci, 1991  ; Milnesium asiaticum Tumanov, 2006  ; Milnesium antarcticum Tumanov, 2006  ; Milnesium longiungue Tumanov, 2006  ; Milnesium zsalakoae Meyer & Hinton, 2010  ; Milnesium barbadosense Meyer & Hinton 2012  ; Milnesium bohleberi Bartels, Nelson, Kaczmarek & Michalczyk, 2014  , Milnesium shilohae Meyer, 2015  ; Milnesium minutum Pilato & Lisi 2016  ; Milnesium sandrae Pilato & Lisi, 2016  and Milnesium tumanovi Pilato, Sabella & Lisi, 2016  .

In the following comparisons, and to save repartition, the detailed quantitative data of the single species are reported in Table 3 where several, significant differences are recognizable; in cases where there are few metric differences (i.e. Milnesium shilohae  and Milnesium minutum  ) these are indicated in the text.

szalokoae, Milnesium barbadosense  , Milnesium tumanovi  , Milnesium sandrae  anđ Milnesium antrcticum  in µm, with the pt inđex values, anđ the percent ratio between the seconđary anđ the

primary claw lengths. The measurements relative to the holotype of Milnesium brachyungue  are slightly đifferent from those inđicateđ in the đescription of the species because in this paper a unique

criterion (đifferent from that useđ by Binđa & Pilato 1990) of measurement for all the species has been ađopteđ. The đata for the holotype of Milnesium szalakoae Meyer & Hinton 2010  , Milnesium 

barbadosense Meyer & Hinton 2012  , anđ the holotype of Milnesium antarcticum Tumanov, 2006  are from the original đescriptions of these species.

Milnesium  Milnesium  Milnesium  Milnesium  Milnesium  Milnesium  Milnesium  Milnesium antarcticum brachyungue  asiaticum  longiungue  szalakoae  barbadosense  tumanovi  sandrae 

. Sliđe 3940 5105 5103 3904 4290 5104 holotype paratype paratype holotype holotype Crimea : Yalta Hawaii Islanđ 

holotype holotype paratype holotype

Bođy length 801 685 747 477 686.4 744 567??

Milnesium validum  sp. nov. differs from Milnesium eurystomum  and Milnesium bohleberi  by having a narrower, cylindrical, instead of a wide, clearly funnel-shaped buccal tube.

Milnesium validum  sp. nov. differs from Milnesium brachyungue  by having higher pt values of both the primary and secondary claw lengths, and lower percent ratio values between the secondary claw and primary claw lengths ( Figs. 6View FIGURE 6 B –D and 7B, C; Tables 2 and 3); this ratio difference is particularly marked for legs IV where the ratio values are 60–63 in Milnesium validum  sp. nov. and c. 81 in Milnesium brachyungue  ( Tables 2 and 3).

The new species differs from Milnesium asiaticum  in having longer buccal tube with respect to the body length (percent ratio c. 11 in the new species and 6.5–8 in Milnesium asiaticum  ) ( Tables 2 and 3); secondary claws stouter with the distal portion clearly wider than the basal portion ( Figs. 6View FIGURE 6 B –D and 8B,C); slightly lower values of the pt index relative to the main branches of claws I –III and, as a consequence, higher percent ratio between the secondary claw lengths and the primary claw lengths ( Table 2 and 3).

Milnesium validum  sp. nov. differs from Milnesium longiungue  by having primary claws with accessory points; stouter secondary claws with the distal portion clearly wider than the basal portion ( Figs. 6View FIGURE 6 B –D and 9B, C); lower pt index values relative to primary claw lengths (the difference is particularly marked in claw IV where the pt value is 46.6–48.4 in the new species and 83–88 in Milnesium longiungue  ); and higher values of the percent ratio between the secondary claw and the primary claw lengths ( Tables 2 and 3).

The new species differs from Milnesium zsalakoae  by having primary claws with accessory points; lower pt index values relative to the primary claws (the difference is particularly marked in claw IV where the pt value is 46.6–48.4 in the new species and 95–103 in Milnesium zsalakoae  according to Meyer & Hinton 2010) ( Tables 2 and 3); and higher percent ratio between the secondary claw lengths and the primary claw lengths ( Table 2 and 3).

Milnesium validum  sp. nov. differs from Milnesium barbadosense  by having eyes; buccal tube clearly longer with respect to the body length (percent ratio c. 11 in the new species, 7–9 on Milnesium barbadosense  ) ( Figs. 6View FIGURE 6 A, and Fig. 1View FIGURE 1 A,B of Meyer & Hinton 2012); stylet supports inserted on the buccal tube in a more anterior position: pt = 61.1–64.8 in the new species, 66–84 in Milnesium barbadosense  according to Meyer & Hinton, 2012 ( Tables 2 and 3.) (N.B we think this very wide range for Milnesium barbadosense  should be confirmed that it is not more than one species).

The new species differs from Milnesium shilohae  in having the stylet supports inserted on the buccal tube in a more cephalic position (pt = 61.1–64.8 in the new species, 75.5–77.5 in Milnesium shilohae  according to Meyer 2015); by having the basal spurs almost as developed as, or more developed than the other points, while in Milnesium shilohae  they are clearly less developed than the other points ( Fig. 6View FIGURE 6 B, D and figure 2 of Meyer 2015).

The new species differs from Milnesium minutum  by having larger body size, narrower buccal tube (the pt index value is 29.9–34.4 in specimens of the new species more than 400 µm long, and about 38.6–42.4 in specimens of Milnesium minutum  about 300 µm long); and it differs in having stouter secondary claws.

Milnesium validum  sp. nov. differs from Milnesium tumanovi  by having buccal tube longer with respect to the body length (the percent ratio is c. 11 in the new species and c. 7 in Milnesium tumanovi  ); and narrow with respect to the buccal tube length (the pt index value is 29.9–34.4 in the new species and c. 55 in Milnesium tumanovi  ); stylet supports inserted on the buccal tube in a more posterior position (pt = 61.1–64.8 in the new species, c. 52 in Milnesium tumanovi  ); stouter secondary claws with basal spur as developed as, or more developed than the other points, while in Milnesium tumanovi  they are clearly less developed than the other points ( Figs. 6View FIGURE 6 B, D and figures 4B, C in Pilato et al. 2016); lower pt index values relative to the secondary claws IV, and lower percent ratio between the secondary claw length and the primary claw length of that pair of legs where the ratio values are 60–63 in the new species, and c. 76 in Milnesium tumanovi  ) ( Tables 2 and 3).

Milnesium validum  sp. nov. differs from Milnesium sandrae  by having buccal tube longer with respect to the body length (the percent ratio is c. 11 in the new species and c. 7 in Milnesium sandrae  ), and narrower with respect to the buccal tube length (the pt index is 29.9–34.4 in the new species, and 45–48 in Milnesium sandrae  ) ( Figs. 6View FIGURE 6 A and 10A); secondary claws slightly stouter ( Figs. 6View FIGURE 6 B –D and 10B,C); slightly lower values of the pt index relative to the secondary claws and lower values of the percent ratio between the secondary and the primary claws (that a ratio is 70.9–75.8 in the claws I –III and 60–63 in claw IV of the new species, while 78.6–85.5 and 70.4–71.4 respectively in Milnesium sandrae  ( Tables 2 and 3).

Milnesium validum  sp. nov. is similar to Milnesium antarcticum  but the stylet supports are inserted on the buccal tube wall in a slightly more cephalic position (pt = 61.1–64.8 in the new species, 66.6–71.3 in Milnesium antarcticum  ); overall, by having clearly stouter secondary claws with shorter basal portion ( Figs. 6View FIGURE 6 B –D and 11B – D), and with the distal point clearly more slender than the basal, while in Milnesium antarcticum  this difference is less marked ( Figs. 6View FIGURE 6 B –D; 11B –D, and figures 17–18 in Tumanov 2006); the pt index values of the claws I –III seem to be slightly higher in the new species ( Tables 2 and 3).

We have to report here and correct a misidentification published by us in a very recent paper (Pilato et al. 2016), regarding our new Milnesium  species ( Milnesium validum  sp. nov.) and Milnesium antarcticum  . In Pilato et al. (2016), we compared Milnesium tumanovi  with a Milnesium antarcticum  from our collection that we had erroneously attributed to Milnesium antarcticum  , and which we are now describing as a new species ( Milnesium validum  sp. nov.).

We had used our best specimen (slide No. 4035, which is now the holotype of Milnesium validum  sp. nov.), as an example of Milnesium antarcticum  , both for the images and measurements (see: figure 8 and table 2 in Pilato et al. 2016). This was done because our specimen was in much better state than the paratypes of Milnesium antarcticum  that are deposited in our collection. As a consequence, photographs published in Pilato et al. (2016), as Milnesium antarcticum  , are actually the holotype of the new species ( Fig 6View FIGURE 6). To eliminate any doubts, Fig. 11View FIGURE 11 presented here is of a paratype of Milnesium antarcticum  (see also figures 17 and 18 in Tumanov 2006), and in Table 3 we indicated quantitative characters of a Milnesium antarcticum  paratype, and the holotype of this species according to Tumanov (2006).

Kingdom

Animalia

Phylum

Tardigrada

Class

Eutardigrada

Order

Apochela

Family

Milnesiidae

Genus

Milnesium

Loc

Milnesium validum

Lisi, Oscar 2017
2017
Loc

Milnesium validum

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium

Lisi 2017
2017
Loc

Milnesium validum

Lisi 2017
2017
Loc

Milnesium minutum

Pilato & Lisi 2016
2016
Loc

Milnesium sandrae

Pilato & Lisi 2016
2016
Loc

Milnesium tumanovi

Pilato, Sabella & Lisi 2016
2016
Loc

Milnesium minutum

Pilato & Lisi 2016
2016
Loc

tumanovi

Pilato, Sabella & Lisi 2016
2016
Loc

sandrae

Pilato & Lisi 2016
2016
Loc

Milnesium shilohae

Meyer 2015
2015
Loc

Milnesium shilohae

Meyer 2015
2015
Loc

Milnesium shilohae

Meyer 2015
2015
Loc

Milnesium shilohae

Meyer 2015
2015
Loc

Milnesium shilohae

Meyer 2015
2015
Loc

Milnesium bohleberi

Bartels, Nelson, Kaczmarek & Michalczyk 2014
2014
Loc

Milnesium barbadosense

Meyer & Hinton 2012
2012
Loc

barbadosense

Meyer & Hinton 2012
2012
Loc

barbadosense

Meyer & Hinton 2012
2012
Loc

Milnesium barbadosense

Meyer & Hinton 2012
2012
Loc

Milnesium barbadosense

Meyer & Hinton 2012
2012
Loc

Milnesium barbadosense

Meyer & Hinton 2012
2012
Loc

Milnesium barbadosense

Meyer & Hinton 2012
2012
Loc

Milnesium zsalakoae

Meyer & Hinton 2010
2010
Loc

szalakoae

Meyer & Hinton 2010
2010
Loc

Milnesium asiaticum

Tumanov 2006
2006
Loc

Milnesium antarcticum

Tumanov 2006
2006
Loc

Milnesium longiungue

Tumanov 2006
2006
Loc

Milnesium antarcticum

Tumanov 2006
2006
Loc

asiaticum

Tumanov 2006
2006
Loc

longiungue

Tumanov 2006
2006
Loc

Milnesium eurystomum

Maucci 1991
1991
Loc

Milnesium brachyungue

Binda & Pilato 1990
1990