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Turkish Journal of Zoology Turk J Zool(2017) 41: 161-163© TÜBİTAKdoi:10.3906/zoo-1510-4

First record of water bears (Tardigrada) from sponges (Porifera)

Joanna TAŁANDA1,*, Krzysztof ZAWIERUCHA2

1Department of Hydrobiology, Faculty of Biology, University of Warsaw, in Biological and Chemical Research Centre, Warsaw, Poland2Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland

* Correspondence: jtalanda@biol.uw.edu.pl

Tardigrades are minute invertebrates found worldwide in aquatic (freshwater and marine) and terrestrial (mosses, lichens, soil) habitats. In aquatic ecosystems tardigrades usually inhabit submerged plants or sediment (Nelson et al., 2015); however, they can also be found in association with other animals. For example, most species of tardigrades belonging to the genus Echiniscoides are found in association with barnacles (Kristensen and Hallas, 1980). Predominantly they are barnacle commensals (feeding on algae) with the exception of Echiniscoides hoepneri Kristensen & Hallas, 1980, which is rather a parasite of these animals (for review, see Kaczmarek et al., 2015). Other parasitic tardigrades are Tetrakentron synaptae Cuénot, 1892, found only in association with holothurians Leptosynapta galliennei Herapath, 1865, and Styraconyx qivitoq Kristensen & Higgins, 1984, found on bryozoans (for review see Kaczmarek et al., 2015).

Lake Ohrid (oligotrophic and karstic reservoir) is located in the central part of the Balkan Peninsula (Mediterranean climatic zone) and is shared between two neighboring countries: Republic of Macedonia and Republic of Albania. Its age is estimated as 2–3 Ma (Wagner and Wilke, 2011). So far over 585 animal species have been recorded in this lake, of which 34% are endemic (Albrecht and Wilke, 2008).

Samples were collected in Lake Ohrid in July 2014 (41°06ʹ25.94ʺN; 20°48ʹ24.47ʺE) and then preserved in 4% formaldehyde. Stones from the bottom of the lake (at depth

1.6 m near high artificial shore) with attached sponges were removed from the water and then sponges were collected (a sample of all sponges from 3 adjacent stones). In addition, a sample of macroalgae from the bottom of the lake and a sample from the concrete shore on the line of water were collected by hand. Samples of sponges and algae were collected and preserved separately. Extraction of tardigrades separately from each sample involved shaking of the substrate in a solution of formaldehyde, taking them out, and then looking through the solution under a stereomicroscope. After extraction, tardigrades were mounted on microscope slides in Hoyer’s medium and then examined using a phase contrast microscope (PCM) (Olympus BX53) equipped with a digital camera (ARTCAM 500MI) and using digital imaging software (Quick PHOTO CAMERA 3.0). The slides are deposited at the Department of Animal Taxonomy and Ecology, Adam Mickiewicz University in Poznań.

In total, three individuals of Isohypsibius sp. (Figures 1–4) were found in the sponge sample and three individuals of Dactylobiotus sp. (Figures 5–8) were found both in algae (two specimens) and sponge samples (one specimen).

In the examined individuals of Isohypsibius sp. important characters of the buccal tube, indicative for defining genera (e.g. Marley et al., 2011), were in poor condition. Moreover, characteristics for other closely related genera features (e.g., Doryphoribius Pilato, 1969,

Abstract: Aquatic species of Tardigrada usually inhabit submerged plants or sediment but they are also known as associated with other animals, like barnacles (Crustacea: Cirripedia) or sea cucumbers (Echinodermata: Holothuroidea). In sponges collected from Lake Ohrid (Macedonia) we found individuals of two tardigrade taxa: Isohypsibius sp. and Dactylobiotus sp. This paper provides the first record of Tardigrada from Macedonia (Lake Ohrid) and is the first report of these animals on sponges.

Key words: Dactylobiotus sp., Isohypsibius sp., Lake Ohrid, water bears

Received: 01.10.2015 Accepted/Published Online: 30.05.2016 Final Version: 25.01.2017

Short Communication

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Pseudobiotus Nelson, 1980, Thulinius R. Bertolani, 2003) like buccal armature or ventral lamina were absent. We attributed our specimens to the genus Isohypsibius Thulin, 1928. Definitive identification of Dactylobiotus sp. specimens was not possible because of the lack of eggs. Egg characteristics are the most important taxonomic features in this genus (Binda and Pilato, 1999).

To summarize, in this paper we presented the first record of Tardigrada from Lake Ohrid and Macedonia as well as first observation of tardigrades on sponges. Porifera may be a new habitat in studies on aquatic tardigrades.

AcknowledgmentsThe first author would like to thank Jakub Baczyński, Ludwik Gąsiorowski, Edwin Sieredziński, and Marta Tischer for giving her the opportunity to take part in the expedition to Lake Ohrid. This research was conducted thanks to financial support from the University of Warsaw (Advisory Board for Students Scientific Movement, Committee on Financing of Scientific and Artistic Circles on Faculty of Biology). The second author is a beneficiary of National Science Center scholarship for PhD No. 2015/16/T/NZ8/00017.

Figures 1–4. Isohypsibius sp.: 1, eyes (arrows) and preserved elements of bucco-pharyngeal apparatus; 2, claws II; 3, cuticular spines; 4, cuticle surface with compacted spines.

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Figure 5–8. Dactylobiotus sp.: 5, dorso-ventral view; 6, bucco-pharyngeal apparatus; 7, claws IV; 8, dorsal papilla/gibbosite like structure on the cuticle surface.

References

Albrecht Ch, Wilke T (2008). Ancient Lake Ohrid: biodiversity and evolution. Hydrobiologia 615: 103-140.

Binda MG, Pilato G  (1999).  Dactylobiotus lombardoi  sp. n. (Eutardigrada: Macrobiotidae) from Tierra del Fuego, with a key to the Dactylobiotus species. Zool Anz 238: 147-155.

Kaczmarek Ł, Bartels PJ, Roszkowska M, Nelson DR (2015). The Zoogeography of Marine Tardigrada. Zootaxa 4037: 1-189.

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Wagner B, Wilke T (2011). Evolutionary and geological history of the Balkan lakes Ohrid and Prespa. Biogeosciences 8: 995-998.