Milnesium almatyense, Tumanov, Denis V., 2006

Tumanov, Denis V., 2006, Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae), Zootaxa 1122, pp. 1-23 : 9-11

Milnesium almatyense sp. nov. ( Figs. 8, 9 , 20–24 , Table 3 )

Type Material. Holotype: sex indeterminate, slide number 199(5). Collected by Mrs. E. Shumilina (St. Petersburg) 27.09.1999, Kazakhstan. Paratypes: slide’s numbers 199(1, 2, 3, 4, 6) from the same locality. Type locality: Kazakhstan, 15 km. southwest from Almaty city. Lichen on the tree trunk. 28 adult and juvenile specimens and 3 exuviae with 10– 13 eggs were found.

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

Description. Body length up to 798 µm; colour of living specimens white, cuticle smooth, no eyes (only in one specimen very poorly developed eyespots seems to be present). Six peribuccal and two lateral papillae present. Mouth with 6 peribuccal lamellae longitudinally striped in their basal portion.

Claws long, slender. Main branch of each claw with small accessory points usually difficult to see, even on the claws of the hind legs. Complex basal claw+secondary branch with poorly developed rounded basal thickening. Outer claws on legs I–III and both claws on hind legs lacks basal spur. First three pairs of legs with elongated cuticular thickening near the claw bases All dimensions are given in Table 3 .

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

No mature males were found.

Milnesium almatyense sp. nov. differs from M. reticulatum by having smooth cuticle without gibbosities, larger body length of adult specimens (672–798 µm in M. almatyense sp. nov. and 270–405 µm in M. reticulatum ), longer buccal tube (37.0–41.4 µm in M. almatyense sp. nov. and 25.0–38.8 µm in M. reticulatum ) and longer claws (pt value of the length of main branches of the claws of the IV pair of legs is 60.0–68.0 in M. almatyense sp. nov. and 41.7–44.3 in M. reticulatum ).

Milnesium almatyense sp. nov. differs from M. katarzynae by having smooth cuticle, larger body length of adult specimens (672–798 µm in M. almatyense sp. nov. and 294.5– 285 µm in M. katarzynae ), more cephalic position of the insertion point of the stylet supports (pt value 65.4–69.6 in M. almatyense sp. nov. and 73.3–78.3 in M. katarzynae ) and longer claws with basal spurs on the inner claws of legs I–III (pt value of the length of main branches of the claws of the IV pair of legs is 60.0–68.0 in M. almatyense sp. nov. and 43.5–43.8 in M. katarzynae ).

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

Milnesium almatyense sp. nov. differs from M. tardigradum by having more slender claws, larger pt ratio of the claws of the IV pair of legs and reduced accessory points on all claws and basal spurs on the outer claws (for comparison see Tables 1 and 3 ).

Milnesium almatyense sp. nov. differs from M. antarcticum sp. nov. by having larger pt ratio of the claws of the IV pair of legs, smaller buccal tube dimensions, more cephalic Milnesium almatyense sp. nov. differs from M. tetralamellatum by having 6 peribuccal lamellae, smaller buccal tube dimensions, more caudal position of the insertion point of the stylet supports (pt value 65.4–69.6 in M. almatyense sp. nov. and 63.9 in M. tetralamellatum ), reduced accessory points on all claws, larger pt ratio of the length of the main branch of the IV pair of legs (60.0–68.0 in M. almatyense sp. nov. and 54.7 in M. tetralamellatum ).

Milnesium almatyense 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 60.0–68.0 in M. almatyense sp. nov. and 33.1 in M. brachyungue ), and longer claws.

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

Figures

FIGURES 2 – 9. Milnesium tardigradum 2 — claws of the III pair of legs, 3 — claws of the IV pair of legs. Milnesium antarcticum sp. nov. 4 — claws of the III pair of legs, 5 — claws of the IV pair of legs. Milnesium reductum sp. nov. 6 — claws of the I pair of legs, 7 — claws of the IV pair of legs. Milnesium almatyense sp. nov. 8 — claws of the II pair of legs, 9 — claws of the IV pair of legs (9 — holotype; 4 ­ 8 — paratypes.

FIGURES 20 – 24. Milnesium almatyense sp. nov. 20 — habitus, 21 — bucco­pharyngeal apparatus, 22 — claws of the II pair of legs, 23 — claws of the IV pair of legs, 24 — main branch of the claw of the IV pair of legs (arrow points to the accessory points) (phase contrast; 20, 23, 24 — holotype, 21 — paratype, 22 — specimen from the type series).

Tables

TABLE 3. Summary of morphometric data for Milnesium almatyense sp. nov. (n = 6).

Character Holotype	Smallest specimen	Largest specimen	Mean (Range)	Standard error
body length (µm) 704.9	671.7	798.0	704.9 (671.7–798.0)	19.35
buccal tube length (µm) 38.5	37.0	41.4	39.4 (37.0–41.4)	0.65
ss (µm) 25.9	24.9	28.9	26.5 (24.9–28.9)	0.56
pt ss 67.3	67.4	69.6	67.3 (65.4–69.6)	0.55
outer buccal tube width (µm) 14.1	16.3	16.3	15.6 (14.1–16.3)	0.34
pt of outer buccal tube width 36.5	44.0	39.3	39.6 (36.5–44.0)	1.02
claw main branch length, leg I (µm) 15.9	17.8	18.5	16.9 (15.5–18.5)	0.47
pt of claw main branch length, leg I 41.3	48.0	44.6	42.9 (38.2–48.0)	1.37
claw base+sec. branch length, leg I (µm) 13.3	13.3	15.5	14.1 (13.3–15.5)	0.34
pt of claw base+sec. branch length, leg I 34.6	36.0	37.5	35.8 (34.5–37.5)	0.46
claw basal branch length, leg I (µm) 5.2	5.4	5.9	5.5 (5.2–5.9)	0.14
bb, leg I 2.6	2.5	2.6	2.6 (2.5–2.7)	0.04
claw main branch length, leg III (µm) 20.7	20.0	20.7	19.7 (18.5–20.7)	0.39
pt of claw main branch length, leg III 53.8	54.0	50.0	50.0 (45.5–54)	1.38
claw base+sec. branch length, leg III (µm) 15.9	15.2	16.3	15.7 (15.2–16.3)	0.21
pt of claw base+sec. branch length, leg III 41.3	41.0	39.3	39.9 (37.3–41.5)	0.67
claw basal branch length, leg III (µm)?	?	7.0	7.0
bb, leg III?	?	2.3	2.3
claw main branch length, leg IV (µm) 24.1	25.2	25.9	25.0 (24.1–26.1)	0.35
pt of claw main branch length, leg IV 62.5	68.0	62.5	63.5 (60.0–68.0)	1.19
claw base+sec. branch length, leg IV (µm) 18.5	17.2	18.5	18.0 (17.2–18.5)	0.20
pt of claw base+sec. branch length, leg IV 48.1	46.6	44.6	45.6 (43.6–48.1)	0.65