Milnesium longiungue, Tumanov, Denis V., 2006

Tumanov, Denis V., 2006, Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae), Zootaxa 1122, pp. 1-23: 18-21

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-2803-C835-FEBD-FB8A8ECED6B8

treatment provided by

Plazi

scientific name

Milnesium longiungue
status

sp. nov.

Milnesium longiungue  sp. nov. ( Figs. 12 –14View FIGURES 10 – 14, 37– 42View FIGURES 37 – 42, Table 6)

Type Material. Holotype: sex indeterminate, slide number 214 (1). Collected by Dr. P. I. Krylov (Zoological Institute of the Russian Academy of Sciences, St. Petersburg) 30.09. 1995, India. Paratypes: slide’s numbers 214 (2, 3, 4, 5, 6) from the same locality. Type locality: India, Hymalaia, Lahaul, road between Keylong and Kardang, 3600–3700 m a.s.l, moss and lichen on rock. 11 adult and juvenile specimens were found.

Etymology. This species is named after its typical character—long claws.

Description. Body length up to 944.3 µm; colour of living specimens white, cuticle smooth, eyes present in most specimens (among 8 adult specimens 3 lack eyes). Six peribuccal and two lateral papillae present. Mouth with 6 peribuccal lamellae longitudinally striped in their basal portion.

Claws very long, slender. Main branch of each claw lacks accessory points. Basal spur of each claw (especially on the IV pair of legs) strongly reduced. Length of the complex basal claw+secondary branch 3–3.5 times exceed length of the basal spur. Complex basal claw+secondary branch with a rounded basal thickening. First three pairs of legs with elongated cuticular thickening near the claw bases. All dimensions are given in Table 6.

Remarks. One adult specimen has strongly modificated claws on legs I. Each leg bears a pair of short claws in the form of a simple hook with basal protrusion ( Fig. 14View FIGURES 10 – 14), which seems to derivate from the complex basal claw+secondary branch, while the main branches are completely reduced. This configuration of the claws is similar to those found in Milnesium tardigradum  (personal observations) and Milnesium tetralamellatum ( Pilato & Binda 1991)  males, but in later two species main branches of claws are present. Although it is not proved by the direct observations of the gonad, it is highly possible that this specimen is also the male.

Milnesium longiungue  sp. nov. differs from M. reticulatum  by having smooth cuticle without gibbosities, more cephalic position of the insertion point of the stylet supports (pt value 59.1–66.7 in M. longiungue  sp. nov. and 68.5–69.8 in M. reticulatum  ) and longer claws with developed basal spurs on the outer claws and without accessory points (pt value of the length of main branches of the claws of the IV pair of legs is 81.8–92.4 in M. longiungue  sp. nov. and 41.7–44.3 in M. reticulatum  ).

Milnesium longiungue  sp. nov. differs from M. katarzynae  by having smooth cuticle, more cephalic position of the insertion point of the stylet supports (pt value 59.1–66.7 in M. longiungue  sp. nov. and 73.3–78.3 in M. katarzynae  ) and longer claws with developed basal spurs on all claws and without accessory points (pt value of the length of main branches of the claws of the IV pair of legs is 81.8–92.4 in M. longiungue  sp. nov. and 43.5–43.8 in M. katarzynae  ).

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

Milnesium longiungue  sp. nov. differs from M. tardigradum  by having longer and more slender claws, larger pt ratio of the claws, reduced accessory points and shorter basal spur (for comparison see Tables 1 and 6).

Milnesium longiungue  sp. nov. differs from M. antarcticum  sp. nov. by having larger pt ratio of the length of the claws of the IV pair of legs, smaller buccal tube dimensions, more cephalic position of the insertion point of the stylet supports, more slender claws with reduced accessory points and shorter basal spur (for comparison see Tables 2 and 6).

Milnesium longiungue  sp. nov. differs from M. asiaticum  sp. nov. by having larger pt ratio of the length of the claws of the IV pair of legs, reduced accessory points and shorter basal spur (for comparison see Tables 4 and 6).

Milnesium longiungue  sp. nov. differs from M. almaaatensis  sp. nov. by having larger pt ratio of the length of the claws of the IV pair of legs, more cephalic position of the insertion point of the stylet supports, reduced accessory points and developed basal spurs on all claws (for comparison see Tables 3 and 6).

Milnesium longiungue  sp. nov. differs from M. reductum  sp. nov. by having larger buccal tube dimensions, longer claws (especially on legs IV), larger pt ratio of the length of the claws of the IV pair of legs and developed basal spurs on the outer claws (for comparison see Tables 5 and 6).

Milnesium longiungue  sp. nov. differs from M. tetralamellatum  by having 6 peribuccal lamellae, longer main branches of all claws (pt value of the length of main branches of the claws of the IV pair of legs is 81.8–92.4 in M. longiungue  sp. nov. and 54.7 in M. tetralamellatum  ), developed basal spurs on the outer claws and reduced accessory points on all claws.

Milnesium longiungue  sp. nov. differs from M. brachyungue  by having larger pt ratio of the claws of legs IV (pt value of the length of main branches of the claws of the IV pair of legs is 81.8–92.4 in M. longiungue  sp. nov. and 33.1 in M. brachyungue  ) and longer claws.

Milnesium longiungue  sp. nov. differs from M. eurystomum  by having typical configuration of buccal apparatus.

TABLE 6. Summary of morphometric data for Milnesium longiungue sp. nov. (n = 8).

    Smallest specimen    
claw base+sec. branch length, leg IV (µm)