Mesobiotus pseudoblocki, Roszkowska, Milena, Stec, Daniel, Ciobanu, Daniel Adrian & Kaczmarek, Łukasz, 2016

Roszkowska, Milena, Stec, Daniel, Ciobanu, Daniel Adrian & Kaczmarek, Łukasz, 2016, Tardigrades from Nahuel Huapi National Park (Argentina, South America) with descriptions of two new Macrobiotidae species, Zootaxa 4105 (3), pp. 243-260: 250-252

publication ID

http://doi.org/10.11646/zootaxa.4105.3.2

publication LSID

lsid:zoobank.org:pub:B0FEF435-9EBF-4C91-AFDB-6F616848FD44

persistent identifier

http://treatment.plazi.org/id/03E10656-FE42-6A4E-E4FB-FC5DE652F847

treatment provided by

Plazi

scientific name

Mesobiotus pseudoblocki
status

sp. nov.

Mesobiotus pseudoblocki View Treatment   sp. nov. ( Table 1 and 2, Figs 4–11 View FIGURES 4 – 6 View FIGURES 7 – 8 View FIGURES 9 – 11 )

http://www.tardigrada.net/register/0022.htm

Localities and number of specimens. IV (8 adults, 1 exuvium, 1 simplex and 3 eggs (one with embryo)

Material examined. Holotype (slide 1476 / 6), seven paratypes (slides: 1476 / 2, 1476 / 3, 1476 / 4 and 1476 / 6), one exuvium (slide 1476 / 3), one simplex (slide 1476 / 6) and three eggs (slides 1476 / 1 and 1476 / 8).

Description (measurements and statistics in Tables 1 and 2). Animals: Body length 270–470 µm ( Fig. 4 View FIGURES 4 – 6 ), white in living specimens and transparent after fixation ( Fig. 4 View FIGURES 4 – 6 ). Eyes present in all specimens before and after fixation in Hoyer’s medium. Cuticle smooth, i.e. without gibbosities, papillae, spines or sculpturing; granulation on all legs absent.

Bucco-pharyngeal apparatus of the Macrobiotus   type, with the ventral lamina and ten peribuccal lamellae ( Fig. 5 View FIGURES 4 – 6 ). Mouth antero-ventral. Oral cavity armature of the harmsworthi type, with three bands of teeth (all visible under PCM) ( Fig. 6 View FIGURES 4 – 6 ). The first band of teeth is present as dots/granules situated at the anterior portion of the oral cavity, on the base of the peribuccal lamellae. The second band of teeth is composed of small ridges parallel to the main axis of the buccal tube, positioned at the rear of the oral cavity, behind the ring fold. The third band of teeth comprises three dorsal and three ventral teeth in the shape of crests, positioned just before the buccal tube opening. Pharyngeal bulb spherical, with triangular apophyses, three macroplacoids and a triangular microplacoid. Macroplacoid length sequence 2 <3 <1. The first macroplacoid narrower in the anterior part, the third with subterminal constriction.

Claws large, of the hufelandi   type ( Figs 7–8 View FIGURES 7 – 8 ). Primary branches with distinct accessory points. Lunules under claws on all legs smooth. Thin cuticular bars under claws I –III present. Other cuticular structures on legs absent.

Eggs: Laid freely, white, spherical and ornamented ( Figs 9–11 View FIGURES 9 – 11 ). Processes in the shape of sharpened cones, elongated in the apical part, sometimes with bifurcated flexible tips and with single or few short filaments ( Fig. 11 View FIGURES 9 – 11 ). In the upper part of processes bubble-like structures are generally present (most typically about 2–5 bubbles), lower down the thick process wall has internal trabeculae that forms a reticulated structure. Around the base of the processes are an obvious crown of dots, which form very small, finger-like structures ( Fig. 10 View FIGURES 9 – 11 ). Surface between processes smooth, without areolation, pores or wrinkles ( Fig. 10 View FIGURES 9 – 11 ).

Etymology. The name of the new species refers to its similarity to Mes. blocki.

Type locality. 41 ° 12 ′S, 71 ° 50 ′W, ca. 1,000 m asl: Río Negro, Nahuel Huapi National Park, Ventisquero Negro, a car parking near a small bar, Nothofagus   forest   , moss from tree, 27.01. 2006, coll. Łukasz Kaczmarek.

Type depositories. Holotype, five paratypes, one exuvium, one simplex and three eggs are deposited at the Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Adam Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznań ( Poland) and two paratypes (slide 1476 / 4) are deposited at the collection of Binda and Pilato, Museum of the Department of Animal Biology ‘Marcello La Greca’, University of Catania, Italy.

Differential diagnosis. The eggs of the new species having processes in form of sharpened cones with bubbles and apical bifurcation are most similar to Mes. blocki ( Dastych 1984). Differences between the species include in Mesobiotus pseudoblocki   sp. nov. smooth lunules on IV pair of legs, the presence of reticular design in the lower parts of egg processes (sparsely distributed dots/ pores in Mes. blocki), the finger-like structures on the bases of egg processes poorly developed but well visible, which never form “pseudo-areolation” (very obvious and well developed in Mes. blocki, when connected forming characteristic “pseudo-areolation”), smaller eggs with/ without processes (62.4–69.4/ 83.4–88.3 µm in Mes. pseudoblocki   sp. nov. vs. 70.0–90.0/ 90.0–130.0 µm in Mes. blocki) and narrower bases of egg processes (5.8–7.6 µm Mes. pseudoblocki   sp. nov. vs. 8.0–14.0 µm in Mes. blocki).

TABLE 1. Measurements [in µm] and pt values of selected morphological structures of Mesobiotus pseudoblocki 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).

          27.5 73.5
          21.9 58.6
          10.9 29.1

TABLE 2. Measurements [in Μm] of selected morphological structures of eggs of Mesobiotus pseudoblocki 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).

  N   MEAN  
    47 % – 70 %   10 %
Number of processes on the egg circumference        
PCM

Polish Collection of Microorganisms