Milnesium dornensis, Roszkowska, Daniel Adrian Ciobanu Milena & Kaczmarek, Łukasz, 2015

Roszkowska, Daniel Adrian Ciobanu Milena & Kaczmarek, Łukasz, 2015, Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov., Zootaxa 3941 (4), pp. 542-564: 544-550

publication ID

http://dx.doi.org/10.11646/zootaxa.3941.4.4

publication LSID

lsid:zoobank.org:pub:66179A2D-14A6-4C5F-91F7-331E7922D1B0

persistent identifier

http://treatment.plazi.org/id/A12287B0-FFCA-FFAA-E6B3-FCA827F90DF4

treatment provided by

Plazi

scientific name

Milnesium dornensis
status

sp. nov.

Milnesium dornensis   sp. nov.

http://www.tardigrada.net/register/0018.htm ( Figs 1 – 14 View FIGURES 1 – 2 View FIGURES 3 – 6 View FIGURES 7 – 10 View FIGURES 11 – 14 , Tables 1 – 2)

Material examined: Holotype (female), 46 paratypes (36 females and 10 males) and five exuvia with 18 smooth eggs.

Description of the adults ( Figures 1 – 2 View FIGURES 1 – 2 ) (measurements in µm, pt ratios and statistics in Tables 1 – 2): Body brownish (in live specimens) or transparent (after fixation in Hoyer’s medium). Eyes present or absent (visible before and after mounting; 68 % of fixed specimens had eyes). Cuticle sculptured with pseudopores (0.5–0.7 Μm in diameter in females and 0.3–0.5 Μm in males), not arranged in bands, sparsely distributed and not forming a reticular design. Under PCM these pseudopores are visible as light spots, placing the species within the granulatum   group ( Figs 4 and 6 View FIGURES 3 – 6 ). On the dorsal side, in the caudal region, an area similar to plate structures is visible ( Fig. 8 View FIGURES 7 – 10 ). These plates are visible only in a few females and at present it is hard to evaluate their taxonomic significance. Six peribuccal papillae and six peribuccal lamellae around the mouth opening present ( Figs 3 and 5 View FIGURES 3 – 6 ). Two cephalic papillae, positioned laterally.

Bucco-pharyngeal apparatus of the Milnesium   type ( Figs 3 and 5 View FIGURES 3 – 6 ). Buccal tube slightly funnel-shaped, wider anteriorly (posterior diameter on average 90 % of the anterior diameter). Pharyngeal bulb elongated, pear-shaped and without placoids or septulum. Claws of the Milnesium   type, slender ( Figs 7, 9 View FIGURES 7 – 10 and 11 – 13 View FIGURES 11 – 14 ). Primary claws on all legs are simple, unbranched with small accessory points detaching from the branch at its greatest curvature ( Figs 10 View FIGURES 7 – 10 and 14 View FIGURES 11 – 14 ). Secondary claws on all legs with rounded basal thickenings (lunules) (sometimes barely visible) ( Figs 9 View FIGURES 7 – 10 and 13 View FIGURES 11 – 14 ). Secondary claws on all legs with three branches (claw configuration: [3 - 3]-[3 - 3]) ( Figs 7, 9 View FIGURES 7 – 10 and 12–13 View FIGURES 11 – 14 ), with the exception of the sexually dimorphic modified claws of the males of first pair of legs ( Fig. 11 View FIGURES 11 – 14 ). Single, long and transverse cuticular bars under claws I – III present ( Figs 7 View FIGURES 7 – 10 and 12 View FIGURES 11 – 14 ). In males, the cuticular bars on first pair of legs distinctly wider than those on legs II –III.

Eggs: Oval, smooth and deposited in exuvium as in all other known Milnesium   species.

Locus typicus: 47 ° 20 ' 13.7 ''N, 25 ° 19 ' 38.8 ''E; 968 m asl: Romania, Suceava County, Vatra Dornei town, lichen ( Usnea   sp.) from tree ( Picea abies   L., H. Karst.).

Etymology: Milnesium dornensis   is named after Vatra Dornei, the town, where the species was found.

Type depositories: Holotype (female; slide: VD- 7), 36 paratypes (29 females and seven males; slides VD 1, VD 2, VD 10, VD 11, VD 13, VD 14) and one exuvium with eggs (slide VD 10) are preserved at the Department of Animal Taxonomy and Ecology, Adam Mickiewicz University in Poznań, Umultowska 89, 61– 614 Poznań, Poland. Additionally, three paratypes (females) (slides: VD 3, VD 4, VD 5) are deposited at the Natural History Museum of “Alexandru Ioan Cuza” University from Iaşi, Romania (Bd. Independenţei No.16, 700101) and eight paratypes (five females and three males; slides: VD 6, VD 8, VD 9, VD 12) are deposited at the Department of Zoology, Comenius University, Bratislava, Slovakia.

Differential diagnosis (for adult females). Based on having a sculptured dorsal cuticle, Milnesium dornensis   sp. nov. belongs to the granulatum   group (Michalczyk et al. 2012 a,b). The new species is most similar to M. alabamae Wallendorf & Miller, 2009   , M. beasleyi Kaczmarek et al., 2012   a, M. granulatum ( Ramazzotti, 1962)   , M. katarzynae Kaczmarek et al., 2004   , M. krzysztofi Kaczmarek & Michalczyk, 2007   , M. lagniappe Meyer et al., 2013   and M. reticulatum Pilato et al., 2002   , but it differs from:

M. alabamae   by: different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming a reticular design in M. dornensis   sp. nov. vs pseudopores arranged in bands (especially in caudal region), densely distributed and forming a reticular design in M. alabamae   ), the presence of accessory points on primary branches of claws and a larger pt of the body length ([1,496–1,986] in M. dornensis   sp. nov. vs [821–1,388] in M. alabamae   ).

M. beasleyi   by: a different claw configuration ([3 - 3]-[3 - 3] in M. dornensis   sp. nov. vs [2-3]-[3 - 2] in M. beasleyi   ), the presence of rounded basal thickenings under secondary branches of claws (sometimes poorly visible), larger pt of peribuccal papillae length ([22.0– 28.3] in M. dornensis   sp. nov. vs [19.6–21.3] in M. beasleyi   ), larger pt of the anterior buccal tube width ([42.5–54.5] in M. dornensis   sp. nov. vs [35.3–41.8] in M. beasleyi   ) larger pt of the anterior primary branch of the claw IV ([57.9 –67.0] in M. dornensis   sp. nov. vs [53.1–57.4] in M. beasleyi   ).

M. granulatum   by: a different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming reticular design in M. dornensis   sp. nov. vs pseudopores densely distributed and forming a reticular design in M. granulatum   ) different lengths of claws on legs IV (see Table 1 below and Table 2 in Bartels et al. (2014) for the exact differences in dimensions of the claws).

M. katarzynae   by: a different claw configuration ([3 - 3]-[3 - 3] in M. dornensis   sp. nov. vs [2 - 2]-[2 - 2] in M. katarzynae   ), different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming a reticular design in M. dornensis   sp. nov. vs pseudopores densely distributed and forming a reticular design in M. katarzynae   ), a larger body size (384 – 874 µm in M. dornensis   sp. nov. vs 285.0 – 294.5 µm in M. katarzynae   ), the stylet supports inserted in a more anterior position ([64.3–68.1] in M. dornensis   sp. nov. vs [73.3–78.3] in M. katarzynae   ), a different buccal tube standard width (9.4–22.7 Μm in M. dornensis   sp. nov. vs 6.6–7.6 Μm in M. katarzynae   ) and a different pt of buccal tube standard width ([37.8–51.6] in M. dornensis   sp. nov. vs [21.7–26.6] in M. katarzynae   ).

M. krzysztofi   by: a different claw configuration ([3 - 3]-[3 - 3] in M. dornensis   sp. nov. vs [2-3]-[3 - 2] in M. krzysztofi   ), a different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming a reticular design in M. dornensis   sp. nov. vs pseudopores densely distributed and forming a reticular design in M. krzysztofi   ), larger pt of the body length ([1,496–1,968] in M. dornensis   sp. nov. vs [1,262–1,425] in M. krzysztofi   ) larger internal/anterior spurs of claws I – IV (I: 4.3 – 6.3 Μm [10.6–14.4]; II: 4.1 – 6.5 Μm [10.3–14.6]; III: 3.5 – 6.2 Μm [11.3–14.3]; IV: 3.5 – 6.6 Μm claws [12.1–17.9] in M. dornensis   sp. nov. vs I: 2.5 – 2.5 Μm [10.1 – 10.1]; II: 2.5 – 2.8 Μm [? – 9.8]; ca. III: 3.4 Μm [ca. 10.8]; IV: 2.7–3.2 Μm [8.0– 10.1] in M. krzysztofi   ).

M. lagniappe   by: a different claw configuration ([3 - 3]-[3 - 3] in M. dornensis   sp. nov. vs [2-3]-[3 - 2] in M. lagniappe   ), a different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming a reticular design in M. dornensis   sp. nov. vs nine dorsal and lateral sculptured bands bearing a reticulated pattern of polygons in M. lagniappe   ), having six peribuccal lamellae (four in M. lagniappe   ), the stylet supports inserted in a more anterior position ([64.3–68.1] in M. dornensis   sp. nov. vs [69.7–73.4] in M. lagniappe   ), smaller pt of width of the buccal tube ([42.5–54.5], [37.8–51.6], [34.8–51.8] anterior, standard and posterior respectively in M. dornensis   sp. nov. vs [68.0– 77.5], [63.4–77.9], [61.8–70.8] anterior, standard and posterior respectively in M. lagniappe   ), a smaller buccal tube standard width/length ratio (38 % – 52 % in M. dornensis   sp. nov. vs 63 % – 78 % in M. lagniappe   ) and a smaller pt of the external base+secondary branch of claws I ([34.2–40.9] in M. dornensis   sp. nov. vs [41.6 –51.0] in M. lagniappe   ).

M. reticulatum   by: a different claw configuration ([3 - 3]-[3 - 3] in M. dornensis   sp. nov. vs [2-3]-[3 - 2] in M. reticulatum   ), a different dorsal sculpture (pseudopores not arranged in bands, sparsely distributed and not forming a reticular design in M. dornensis   sp. nov. vs pseudopores arranged in nine sculptured bands, forming a reticular design in M. reticulatum   ), absence of cuticular gibbosities, having six peribuccal lamellae (four in M. reticulatum   ), the stylet supports inserted in a more anterior position ([64.3–68.1] in M. dornensis   sp. nov. vs [68.5–69.8] in M. reticulatum   ) and larger claws I – IV (see Table 1 below and Table 2 in Pilato et al. (2002) for the exact differences in dimensions of the claws).

TABLE 1. Measurements and pt values of selected morphological structures of fifteen females from the type population of Milnesium dornensis sp. nov. mounted in Hoyer’s medium (N—number of specimens / structures measured, RANGE refers to the smallest and the largest structure among all measured specimens; SD—standard deviation).

  15     152 144  
  14        
  15        
  14        
  15        
  15        
  15        
  15        
  15        
  14        
  14        
  14        
  14        
  10        
  15        
  14        
  15        
  14        
  15        
  13        
  10        
  14        
  13        
  13        
  12        
  12        
  13        
  13        

TABLE 2. Measurements and pt values of selected morphological structures of ten males from the type population of Milnesium dornensis sp. nov. mounted in Hoyer’s medium (N—number of specimens / structures measured, RANGE refers to the smallest and the largest structure among all measured specimens; SD—standard deviation).

  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
  10      
PCM

Polish Collection of Microorganisms