First observation of the marine tardigradesBatillipes mirusandBatillipes noerrevangi(Arthrotardigrada, Batillipedidae) from a strongly brackish part of the Polish Baltic Sea coast

Abstract

The tardigrade fauna of Poland is one of the better known in Europe. However, almost all studies have been carried out on the limno-terrestrial species, while marine Tardigrada have been neglected. To the best of our knowledge only one report on marine Tardigrada for Polish waters has been published up to now. In the present study the first records of two marine arthrotardigrade species, Batillipes mirus and Batillipes noerrevangi, from Puck Bay (Baltic Sea) are reported. The lowest salinity value in the study area was 3-4 PSU, and B. noerrevangi should be considered the most brackish water-tolerant arthrotardigrade. Samples were collected from the vegetated seabed (seagrass and macrophytes) and the bare sandy bottom in different seasons. A single specimen of B. mirus was found only during the autumn campaign. Specimens (adults and larval stages) of B. noerrevangi were found in all samples during spring, summer and autumn campaigns. Additionally, morphometric data with detailed microphotographs of B. noerrevangi (PCM, DIC) and B. mirus (PCM) as well as a discussion of the new records are presented. The validity of the occurrence of B. dicrocercus in Poland, which was determined based on a single larva from the Międzyzdroje area by Hummon, is also discussed. The larva from Międzyzdroje should be regarded as an undetermined species; thus, the marine tardigrade fauna from Poland consists of only the two newly recorded species.

Time-series transcriptomic screening of factors contributing to the cross-tolerance to UV radiation and anhydrobiosis in tardigrades

“…This protein family is conserved widely in Tardigrada, even in Batillipes sp., a non-anhydrobiotic heterotardigrade species. Although this intertidal marine inhabiting Batillipes is not capable of anhydrobiosis, it is capable of surviving short periods of high and low levels of salinity and inhabiting brackish regions [ 57 , 58 ], suggesting tolerance against fluctuations in osmolarity. Such fluctuations would induce physiologies partly mirroring anhydrobiosis.…”

The first record of Macrobiotus vladimiri Bertolani, Biserov, Rebecchi & Cesari, 2011 (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group) from Poland

“…Studies on Polish tardigrades have been conducted for more than a century (Minkiewicz, 1914;Jakubski, 1915), and up to now, 102 species have been reported from this country (e.g., Kaczmarek, 2008;Kaczmarek et al, 2010;Zawierucha et al, 2015). However, the most comprehensive account on this subject so far is that of Dastych (1988).…”

Batillipes (Tardigrada, Arthrotardigrada) from the Portuguese coast with the description of two new species and a new dichotomous key for all species

“…Despite the interesting biological information that they can provide (de Zio grimaldi & gallo D'Addabbo 2001;Faurby et al 2011Faurby et al , 2012, biogeographical studies on marine tardigrades, and especially on Batillipes, are scarce, often restricted to generalist lists (e.g., Kaczmarek et al 2015;Miller & Perry 2016) and sometimes leading to contradictory interpretations. Actually, results of recent studies suggested that geographic / ecological factors can act as barriers, promoting speciation (e.g., Faurby et al 2011Faurby et al , 2012Zawierucha et al 2015;Faurby & Barber 2015) contrary to hypotheses in favour of wide-ranging species (e.g., hummon 1994). Therefore, further studies in new habitats such as different depths (e.g., hansen 2005), diverse environmental gradients (e.g., Pollock 1970bPollock , 1989Kristensen & Mackness 2000;Faurby et al 2012) or types of substrates (e.g., Rubal et al 2016), would enhance our understanding of tardigrade distribution, and, particularly, could be pivotal to our understanding of the biogeography of the genus Batillipes.…”

“…Difficulties are increased by the small number of taxonomic characters available and by the marked variability observed in some characters (e.g., McKirdy 1975;gallo D'Addabbo et al 2000). on the other hand, the use of morphometric data for taxonomic purposes must be carefully used because measurements can be biased by specimen orientation or by the physical slide mounting processes (see Mcginty & higgins 1968;Pollock 1971;Kristensen 1978;Morone De Lucia et al 1988;Villora-Moreno & de Zio grimaldi 1993;gallo D'Addabbo et al 2000;Kristensen & Mackness 2000;Zawierucha et al 2015;Fontoura et al 2017;Santos et al 2017). For these reasons, some of the old descriptions of species of Batillipes are incomplete and they may represent complexes of similar species, e.g., cosmopolitan B. mirus and B. pennaki as suggested by Zawierucha et al (2013Zawierucha et al ( , 2015.…”

“…on the other hand, the use of morphometric data for taxonomic purposes must be carefully used because measurements can be biased by specimen orientation or by the physical slide mounting processes (see Mcginty & higgins 1968;Pollock 1971;Kristensen 1978;Morone De Lucia et al 1988;Villora-Moreno & de Zio grimaldi 1993;gallo D'Addabbo et al 2000;Kristensen & Mackness 2000;Zawierucha et al 2015;Fontoura et al 2017;Santos et al 2017). For these reasons, some of the old descriptions of species of Batillipes are incomplete and they may represent complexes of similar species, e.g., cosmopolitan B. mirus and B. pennaki as suggested by Zawierucha et al (2013Zawierucha et al ( , 2015. In order to solve the problems that affect the taxonomy of the genus, research should focus on characters previously neglected for marine tardigrades (gallo D'Addabbo et al 2000).…”