Milnesium asiaticum, Tumanov, Denis V., 2006

Tumanov, Denis V., 2006, Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae), Zootaxa 1122, pp. 1-23 : 12-15

Milnesium asiaticum sp. nov. ( Figs. 10, 11 , 25–29 , Table 4 )

Type Material. Holotype: sex indeterminate, slide number 194(14). Collected by A. V. Barabanov (Zoological Institute of the Russian Academy of Sciences, St. Petersburg) 17.06.1998, Kirghizia.

Paratypes: slide’s numbers 195(17, 19, 20, 22) from the same locality. Type locality: Kirghizia, Chui Area, northern slope of the Kirghizian ridge, Turakaiyn canyon, vicinity of Turakaiyn village, near 2000 m a.s.l., moss from soil. 5 adults and juvenile specimens and 1 exuvium with 9 eggs were found.

Additional material: slide’s numbers 190(16, 17, 18). Collected by Dr. I. G. Danylov (Zoological Institute of the Russian Academy of Sciences, St. Petersburg) 16.06.1998, in Kirghizia, Osh Area, Karakuljin Distr., vicinity of Kylojun village, near 2000 m a.s.l., moss from stone (3 adults).

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

Description. Body length up to 911.1 µm; colour of living specimens slightly reddish or white, cuticle smooth, eyes present in most specimens. Six peribuccal and two lateral papillae present. The mouth has 6 peribuccal lamellae longitudinally striped in their basal portion.

Claws long, slender. Main branch of each claw with two poorly developed accessory points. 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 4 .

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

No mature males were found.

Differential Diagnosis. Milnesium asiaticum 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 63.9–66.9 in M. asiaticum sp. nov. and 68.5–69.8 in M. reticulatum ) and longer claws with developed basal spurs on the outer claws (pt value of the length of main branches of the claws of the IV pair of legs is 63.9–76.0 in M. asiaticum sp. nov. and 41.7–44.3 in M. reticulatum ).

Milnesium asiaticum sp. nov. differs from M. katarzynae by having smooth cuticle, more cephalic position of the insertion point of the stylet supports (pt value 63.9–66.9 in M. asiaticum sp. nov. and 73.3–78.3 in M. katarzynae ) and longer claws with developed basal spurs on all claws (pt value of the length of main branches of the claws of the IV pair of legs is 63.9–76.0 in M. asiaticum sp. nov. and 43.5–43.8 in M. katarzynae ).

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

Milnesium asiaticum sp. nov. differs from M. tardigradum by having more slender and longer claws, larger pt ratio of the length of the claws of the IV pair of legs and less developed accessory points (for comparison see Tables 1 and 4 ).

Milnesium asiaticum sp. nov. differs from M. almatyense sp. nov. by having longer buccal tube, longer claws (especially on the IV pair of legs) and developed basal spurs on all claws (for comparison see Tables 3 and 4 ).

Milnesium asiaticum sp. nov. differs from M. antarcticum sp. nov. by having smaller buccal tube dimensions, more cephalic position of the insertion point of the stylet supports, more slender claws, larger pt ratio of the length of the claws of the IV pair of legs, less developed accessory points (for comparison see Tables 2 and 4 ).

Milnesium asiaticum sp. nov. differs from M. tetralamellatum by having 6 peribuccal lamellae, larger buccal tube length, slightly more caudal position of the insertion point of the stylet supports (pt value 63.9–66.9 in M. asiaticum sp. nov. and 63.9 in M. tetralamellatum ), longer claws with developed basal spurs on the outer claws, lesser pt ratio of the length of the complex basal claw+secondary branch of the IV pair of legs (36.8–46.7 in M. asiaticum sp. nov. and 46.2 in M. tetralamellatum ) and larger pt ratio of the length of the main branch of the IV pair of legs (63.9–76.0 in M. asiaticum sp. nov. and 54.7 in M. tetralamellatum ).

Milnesium asiaticum 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 63.9–76.0 in M. asiaticum sp. nov. and 33.1 in M. brachyungue ) and longer claws.

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

Figures

FIGURES 10 – 14. Milnesium asiaticum sp. nov. 10 — claws of the I pair of legs, 11 — claws of the IV pair of legs. Milnesium longiungue sp. nov. 12 — claws of the I pair of legs, 13 — claws of the IV pair of legs, 14 — abnormal claws of the I pair of legs (presumable male) (12, 13 — holotype; 10, 11 — paratype).

FIGURES 25 – 29. Milnesium asiaticum sp. nov. 25 — habitus, 26 — bucco­pharyngeal apparatus, 27 — claws of the I pair of legs, 28 — claws of the IV pair of legs, 29 — main branch of the claw of the I pair of legs (arrow points to the accessory points) (phase contrast; 25 – 28 — holotype).

Tables

TABLE 4. Summary of morphometric data for Milnesium asiaticum sp. nov. (n = 10).

Character Holotype	Smallest specimen	Largest specimen	Mean (Range)	Standard error
body length (µm) 857.9	638.4	911.1	762.8 (638.4–911.1)	29.56
buccal tube length (µm) 56.2	50.3	55.5	53.1 (50.3–57.0)	0.77
ss (µm) 37.0	33.7	35.5	34.6 (32.6–37)	0.46
pt ss 65.8	66.9	64.0	65.3 (63.9–66.9)	0.38
outer buccal tube width (µm)?	18.1	?	18.5 (15.5–23.7)	0.89
pt of outer buccal tube width?	36.0	?	35.2 (30.0–41.6)	1.34
claw main branch length, leg I (µm) 28.9	20.0	30.0	25.4 (20.0–30.0)	1.03
pt of claw main branch length, leg I 51.3	39.7	54.0	47.7 (39.7–54.0)	1.38
claw base+sec. branch length, leg I (µm) 19.2	14.8	20.0	17.2 (14.8–20.0)	0.58
pt of claw base+sec. branch length, leg I 34.2	29.4	36.0	32.4 (29.2–36.0)	0.73
claw basal branch length, leg I (µm) 8.9	6.7	9.3	7.8 (6.7–9.3)	0.25
bb, leg I 2.2	2.2	2.2	2.2 (2.1–2.6)	0.05
claw main branch length, leg III (µm) 32.6	25.9	31.8	29.4 (25.9–32.6)	0.86
pt of claw main branch length, leg III 57.9	51.5	57.3	55.3 (51.5–58.3)	0.89
claw base+sec. branch length, leg III (µm) 19.2	15.5	20.7	18.1 (15.5–20.7)	0.56
pt of claw base+sec. branch length, leg III 34.2	30.9	37.3	34.1 (30.9–37.3)	0.67
claw basal branch length, leg III (µm) 10.4	7.4	9.3	8.3 (7.4–10.4)	0.32
bb, leg III 1.9	2.1	2.2	2.2 (1.9–2.4)	0.05
claw main branch length, leg IV (µm) 40.7	32.6	42.2	36.8 (32.6–42.2)	1.14
pt of claw main branch length, leg IV 72.4	64.7	76.0	69.7 (63.9–76.0)	1.43
claw base+sec. branch length, leg IV (µm) 22.2	20.0	25.9	21.6 (19.6–25.9)	0.65
pt of claw base+sec. branch length, leg IV 39.5	39.7	46.7	41.1 (36.8­46.7)	0.96
claw basal branch length, leg IV (µm) 10.4	0.0	9.6	9.2 (8.1­10.7)	0.37
bb, leg IV 2.1	2.1	2.2	2.4 (2.1­2.7)	0.09