Milnesium antarcticum, Tumanov, Denis V., 2006

Tumanov, Denis V., 2006, Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae), Zootaxa 1122, pp. 1-23: 2-5

publication ID

http://doi.org/ 10.5281/zenodo.171737

publication LSID

lsid:zoobank.org:pub:920D938D-F578-47BE-B7E7-50DD7864703D

persistent identifier

http://treatment.plazi.org/id/B32287EE-2813-C825-FEBD-FA0D8ECFD767

treatment provided by

Plazi

scientific name

Milnesium antarcticum
status

sp. nov.

Milnesium antarcticum   sp. nov. ( Figs. 4, 5 View FIGURES 2 – 9 , 15–19 View FIGURES 15 – 19 , Table 2)

Type material. Holotype: sex indeterminate, slide number 89 (22). Collected by Dr. P. I. Krylov (Zoological Institute of the Russian Academy of Sciences, St. Petersburg) 15.12. 1985, King George Island, Antarctica. Paratypes: slide’s numbers 89 (1, 5, 17, 18, 19, 23) from the same locality. Type locality: Antarctica, King George Island, vicinity of Henryka Arctowskiego Polish polar station, moss in a little stream from under snowfield. 27 adult and juvenile specimens and 1 exuvium with three eggs were found.

Etymology. This species is named after the region of its type locality, Antarctica.

Description. Large animals, exact body length could not be measured, because of the strong constriction during fixation (even in constricted condition it exceed 800 µm), colour of the fixed specimens reddish­brown; cuticle smooth; eyes present. Six peribuccal and two lateral papillae present. Mouth with 6 peribuccal lamellae longitudinally striped in their basal portion. Buccal tube wide and long.

Claws large, massive. Main branch of each claw with two well developed accessory points. Complex basal claw+secondary branch with well developed rounded basal thickening. First three pairs of legs with elongated cuticular thickening near the claw bases. All dimensions are given in Table 2.

Smooth eggs (white in incident light, colourless in preparation) deposited within exuviae.

No mature males were found.

Differential Diagnosis. Milnesium antarcticum   sp. nov. differs from Milnesium reticulatum   by having smooth cuticle without gibbosities, more caudal position of the insertion point of the stylet supports (pt value 70.0– 73.7 in M. antarcticum   sp. nov. and 68.5–69.8 in M. reticulatum   ), claws with developed basal spurs on the outer claws and larger pt ratio of the length of main branches of the claws of the IV pair of legs (49.8–55.9 in M. antarcticum   sp. nov. and 41.7–44.3 in M. reticulatum   ).

Milnesium antarcticum   sp. nov. differs from M. katarzynae   by having smooth cuticle, slightly more cephalic position of the insertion point of the stylet supports (pt value 70.0– 73.7 in M. antarcticum   sp. nov. and 73.3–78.3 in M. katarzynae   ), claws with developed basal spurs on all claws and larger pt ratio of the length of main branches of the claws of the IV pair of legs (49.8–55.9 in M. antarcticum   sp. nov. and 43.8 – 43.5 in M. katarzynae   ).

Milnesium antarcticum   sp. nov. differs from Milnesium dujiangensis   by having main claw branches on all legs.

Milnesium antarcticum   sp. nov. differs from M. tardigradum   by larger buccal tube and claws’ dimensions and more caudal position of the insertion point of the stylet supports (for comparison see Tables 1 and 2).

Milnesium antarcticum   sp. nov. differs from M. tetralamellatum   by having 6 peribuccal lamellae, lesser pt ratio of the length of the complex basal claw+secondary branch of the IV pair of legs (28.0– 34.3 in M. antarcticum   sp. nov. and 46.2 in M. tetralamellatum   ), larger buccal tube dimensions, more caudal position of the insertion point of the stylet supports (pt value 70.0– 73.7 in M. antarcticum   sp. nov. and 63.9 in M. tetralamellatum   ) and claws with developed basal spurs on the outer claws.

Milnesium antarcticum   sp. nov. differs from M. brachyungue   by having larger pt ratio of the length of the claws of the IV pair of legs (pt value of the length of main branches of the claws of the IV pair of legs is 49.8–55.9 in M. antarcticum   sp. nov. and 33.1 in M. brachyungue   ), more caudal position of the insertion point of the stylet supports (pt value 70.0– 73.7 in M. antarcticum   sp. nov. and 69.4 in M. brachyungue   ) and longer claws. Milnesium antarcticum   sp. nov. differs from M. eurystomum   by having typical configuration of buccal apparatus.

TABLE 2. Summary of morphometric data for Milnesium antarcticum sp. nov. (n = 15).

claw base+sec. branch length, leg IV (µm)   22.2 (19.6–25.2)  
    31.2 (28.0–34.3)  

TABLE 1. Summary of morphometric data for Milnesium tardigradum (European populations) (n = 6).

      Mean (Range) Standard error 652.8 (598.5–704.9) 18.68 49.4 (46.6–53.3) 1.22