ISSN 1812-9250 
ISSN 1814-0815





Volume 8, Number 1

Published online 3/09/2011


Vladimir Ivanovich Biserov. 13.08.1951 31.10.1998, by N.M. Biserova

(in English)

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(in Russian)

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Ecology of the terrestrial and freshwater tardigrades (Tardigrada): autecological aspect

A.M. Avdonina

The Russian Academy of Economics and Public Administration under the President of the Russian Federation, Vladimir branch, Gorkogo Str. 59A, 600017 Vladimir, Russia.

ABTRACT: This review generalizes the autecological data on terrestrial and freshwater tardigrades for the 100 past years, systematizing the research results showing the influence of the various environmental factors on tardigrades and adaptations of these amazing animals. Autecological researches help to understand the distribution of tardigrades in recent conditions, and also show the potential of these animals. The extraordinary tardigrade tolerance to ionizing radiation, high pressure and low temperatures in the anhydrobiosis gives the key to solve the problem of organism survival in extraterrestrial environments. In spite of the high tolerance to the significant anthropogenic exposure, such as influence of transport emissions, industrial pollution, cuttings, fires, etc., many among them change the quantitative and qualitative composition of tardigradofauna. Therefore Tardigrada can be used as biological indicators of air pollution, particularly by the sulfur dioxide and the heavy metals.

KEY WORDS: tardigrades (Tardigrada), ecology, autecology, ecological factor, moisture, oxygen, temperature, light, altitude, radiation, food, space, anhydrobiosis.

(in Russian with English Summary)

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Taxonomy and biogeography of tardigrades using an integrated approach: new results on species of the Macrobiotus hufelandi group

R. Bertolani1, V. Biserov2, L. Rebecchi1, M. Cesari1

1 Department of Biology, University of Modena and Reggio Emilia, Via Campi 213/D, 41125 Modena, Italy.

2 Institute of Inland Water Biology, Academy of Sciences of Russia, Borok, Yaroslavl District, Russia

ABSTRACT: This study considers in a new light a population already studied and tentatively attributed to Macrobiotus cf. terminalis (Bertolani, Rebecchi, 1993), by joining molecular approaches to the traditional, but indispensable, light microscopy, and to scanning electron microscopy. Differences in animal and, above all, egg shell morphology, and the peculiar cox1 sequence indicate that this population clearly pertains to a new species, M. vladimiri sp.n., which is here described. The results obtained can be considered as an example of how a modern taxonomical and biogeographical research can be carried out on this animal phylum and in general on the animals belonging to the so called meiofauna, where characters bound to morphology are often very few. This is the first tardigrade species to be described and barcoded contemporarily.

KEY WORDS: tardigrades, Macrobiotus, DNA barcoding, cox1, biogeography, taxonomy.

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Tardigrades in bottom meiofauna in different waterbodies of the Upper Volga Basin

V.A. Gusakov

Institute for Biology of Inland Water, Russian Academy of Sciences, Borok, Yaroslavl district, 152742, Russia.

ABSTRACT: This paper describes the results of investigations of tardigrades as a part of meiobenthos in different waterbodies (rivers, lakes, reservoirs) of the Upper Volga basin. To the present time 21 species of freshwater Tardigrada have been found in the region. In the investigated waterbodies the most widespread and numerous species were Pseudobiotus megalonyx (Thulin, 1928), Isohypsibius granulifer Thulin, 1928, Dactylobiotus selenicus Bertolani, 1981 and Thulinia ruffoi Bertolani, 1981. The first of them is met in the majority of biotopes. In the reservoirs the tardigrades can make up over 50% of the total number and 30% of meiobenthos biomass even at a high abundance of other organisms. The maximal population density was registered for P. megalonyx in the Gorky Reservoir 225.7 thous. ind./m2 and 3.5 g/m2. The seasonal and long term abundance dynamics of tardigrades (in the Rybinsk Reservoir as an example) are complicated. In some years they are almost completely absent in samples, in other reach a significant amount. The maximal number of tardigrades individuals occurs in mid March late June. In different years in this period 13 peaks of abundance are registered for various species, the greatest usually, in May at temperature ~1215C. Changes in the abundance dynamics of the taxonomic group and separate species are similar both in profundal and open inshore zone, hence they are determined, mainly, by climatic factors. During the autumn-winter decrease of the reservoir level in the drained and frozen sediments of littoral P. megalonyx, D. selenicus and I. granulifer at mature age retain their vitality not less than for 711 weeks. The aggregated distribution in biotopes is typical for tardigrades, apparently, owing to low motility. Even under similar living conditions the density of populations differs by orders of magnitude. Because of considerable fluctuations of  tardigrades abundance by years, seasons, biotopes and within similar biotopes long term investigations are necessary for obtaining reliable data on their distribution and population dynamics in waterbodies.

KEY WORDS: Tardigrada, Upper Volga, species composition, quantitative parameters, seasonal and long term dynamics.

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Macrobiotus trunovae sp.n., a new species of tardigrade from Russia

Vladimir Biserov1, Giovanni Pilato2, Oscar Lisi2 

1 Institute of Biology of Inland Waters, USSR Academy of Sciences, Borok, Yaroslav District.

2 Department of Animal Biology Marcello La Greca, University of Catania, Via Androne 81, 95124 Catania, Italy.

ABSTRACT: Biserov cited the new species Macrobiotus trunovae sp.n. in a paper of 1996 before publishing its description and, unfortunately, he died prematurely. The description of the new species is finished here. M. trunovae sp.n. belongs to the Macrobiotus hufelandi group and differs from most species of the group for the large body size and, overall, for some characters of the egg which have processes very close to one another, and the egg shell with dots sometimes forming a very irregular reticular design.

KEY WORDS: Tardigrada, Macrobiotus trunovae sp.n., Russia.

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The ultrastructure of the tardigrade spermatozoon: a comparison between Paramacrobiotus and Macrobiotus species (Eutardigrada)

L. Rebecchi, T. Altiero, A. Guidi

Department of Biology, University of Modena and Reggio Emilia, Via Campi 213/D 41125 Modena, Italy.

Abstract: The spermatozoan ultrastructure was investigated in three semiterrestrial eutardigrade species belonging to two different genera of Macrobiotidae (Paramacrobiotus and Macrobiotus). The spermatozoa of P. areolatus and P. richtersi are very similar and are made by three regions, namely a long head, a short kidney-shaped middle piece and a short tail with its terminal tuft. In both species the spermatozoa are particularly long (up to 100 m) and very thin. The peculiar length is due to the remarkably developed head consisting of a cylindrical acrosome and a weakly coiled nucleus increasing in width caudally. The presence of a long nucleus, an electron-dense core of fibrils running parallel to the nucleus, as well as nine outer electron-dense fibers around the proximal part of the axoneme represents novelties in the ultrastructure of the tardigrade spermatozoa. These structures, never described before for a tardigrade spermatozoon, could be related to the movement of those extraordinary long male gametes of Paramacrobiotus. The spermatozoon of M. harmsworthi too is made up of three regions: the head, including the acrosome and nuclear region, the middle piece and the terminally tufted tail. Nevertheless it is only 4650 m in length and the head, including a slightly tight helical nuclear region, is similar in length to the tail. In all macrobiotid species here examined, including those from literature, the spermatozoa within the was deferens always appear folded, with the hinge located between the end of the head and the beginning of the middle piece, thus resembling a long nutcracker. The use of spermatozoan characters as phylogenetic information in tardigrades is also discussed.

Key words: Tardigrada, Macrobiotidae, Paramacrobiotus, Macrobiotus, Spermatozoon, Ultrastructure, Phylogeny.

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Marine tardigrade Halechiniscus jejuensis Chang et Rho, 2002 (Arthrotardigrada: Halechiniscidae) found in Vietnam

Alexei V. Tchesunov

Department of Invertebrate Zoology, Faculty of Biology, Moscow State University, Moscow, 119991, Russia.

ABSTRACT: Halechiniscus jejuensis Chang et Rho, 2002 is found and briefly described from a mangrove habitat in the Nha Trang area, Central Vietnam. The species was originally described at the southernmost point of the Korean Peninsula, hence the new find extends considerably the geographic distribution of the species southwards to the tropical zone. The Vietnamese specimens slightly differ from the Korean ones in shape and number of the lateral body expansions. A peculiar feature of the Vietnamese specimens is development of thread-like colonial prokaryotes on ventral surface of the head.

KEY WORDS: Halechiniscus jejuensis, marine tardigrades, mangroves, Vietnam.

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