en>Gaba p: Added {{merge to}} tag to article (TW)

2013-09-24T13:15:54Z

Added {{merge to}} tag to article (TW)

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{{Taxobox
| name = ''Zospeum tholussum''
| image = Holotype of Zospeum tholussum - SubtBiol-011-045-g002.jpg
| image_caption = ''Zospeum tholussum''
| image2 = A live individual of Zospeum tholussum.jpg
| image2_caption =The shells of living specimens of ''Zospeum tholussum'' are translucent.
| status =
| regnum = [[Animal]]ia
| phylum = [[Mollusca]]
| classis = [[Gastropoda]]
| unranked_superfamilia =
clade [[Heterobranchia]]<br/>
clade [[Euthyneura]]<br/>clade [[Panpulmonata]]<br/>
clade [[Eupulmonata]]
| superfamilia = [[Ellobioidea]]
| familia = [[Ellobiidae]]
| subfamilia = [[Carychiinae]]
| genus = ''[[Zospeum]]''
| species = '''''Z. tholussum'''''
| binomial = ''Zospeum tholussum''
| binomial_authority = [[Alexander M. Weigand|Weigand]], 2013
| range_map =
| range_map_caption =
}}

'''''Zospeum tholussum''''' is a [[troglofauna|cave-dwelling]] [[species]] of [[pulmonate|air-breathing]] [[land snail]]s in the family [[Ellobiidae]]. It is a very small species with a shell height of less than {{convert|2|mm|in|abbr=on|2}} and a shell width of around {{convert|1|mm|in|abbr=on|2}}. ''Z. tholussum'' individuals are completely blind and possess translucent shells with five to six whorls. The second whorl of their shells has a characteristic dome-like shape. They are also extremely slow-moving and may depend on passive transportation through running water or larger animals for dispersal.

''Zospeum tholussum'' was discovered at depths of {{convert|743|to|1392|m|ft|abbr=on}} in the [[Lukina jama|Lukina jama–Trojama]] cave system in [[Croatia]] in 2010 during a [[caving]] expedition. It was formally described as a new species in 2013 by the taxonomist Dr. Alexander M. Weigand.

==Discovery==
Specimens of ''Zospeum tholussum'' were recovered by a team of [[caving|cavers]] and [[biologist]]s of the [[Croatian Biospeleological Society]] (Hrvatsko Biospeleološko Društvo or HBSD) from the [[Lukina jama|Lukina jama–Trojama]] [[cave system]] in the [[Velebit]] mountains of [[Croatia]], during an expedition from July 29 to August 8, 2010.<ref name="Weigand">{{cite journal|author=Alexander M. Weigand|year=2013|title=New ''Zospeum'' species (Gastropoda, Ellobioidea, Carychiidae) from 980 m depth in the Lukina jama–Trojama cave system (Velebit Mts., Croatia)|journal=Subterranean Biology|volume=11|pages=45–53|doi=10.3897/subtbiol.11.5966|url=http://www.pensoft.net/J_FILES/13/articles/5966/5966-G-3-layout.pdf}}</ref> The cave system is the deepest in Croatia and one of the top twenty deepest caves in the world at a total measured depth of {{convert|1421|m|ft|abbr=on}}, including submerged passages.<ref name="lukina">{{cite web|url=http://www.speleologija.hr/lukinajama/index_en.html|title=Lukina jama (Pit): Cave System Lukina jama - Trojama|author= The Speleological Committee of the Croatian Mountaineering Association|date=October 27, 2010|publisher=Croatian Speleological Server}}</ref><ref name="yt">{{cite web|url=http://www.youtube.com/watch?v=QuU5DgG2nRY|title=Expedition Lukina jama 2010|author=PDS Velebit & Speleološki Odsjek Velebit|date=April 24, 2013|publisher=YouTube|language=Croatian|accessdate=October 21, 2013}}</ref> Aside from its great depth, the cave system is also known for its vertical orientation and deep shafts.<ref name="earthsky">{{cite web|url=http://earthsky.org/science-wire/a-new-beautiful-translucent-snail-from-the-deepest-cave-in-croatia|title=A new beautiful translucent snail from the deepest cave in Croatia|date=September 10, 2013|publisher=EarthSky|accessdate=October 20, 2013}}</ref><ref name="huff">{{cite web|url=http://www.huffingtonpost.com/2013/09/16/transparent-snail_n_3936796.html|title=Transparent Snail, ''Zospeum tholussum'', Discovered In Croatia|author=Laura Poppick|date=September 16, 2013|publisher=Huffington Post|accessdate=October 20, 2013}}</ref><ref name="anderson">{{cite web|url=http://www.sci-news.com/biology/science-snail-semi-transparent-shell-croatia-01381.html|title=New Snail Species with Semi-Transparent Shell Discovered in Croatia|author= Natali Anderson|date=September 16, 2013|publisher=Sci-News|accessdate=October 20, 2013}}</ref>

The expedition was primarily to determine the cave system's depth,<ref name="ibt">{{cite web|url=http://www.ibtimes.com/new-snail-species-discovered-croatian-cave-zospeum-tholussum-creep-circles-photos-1406432|title=New Snail Species Discovered In Croatian Cave, ''Zospeum tholussum'' ‘Creep’ In Circles|author= Zoë Mintz|date=September 16, 2013|publisher=International Business Times|accessdate=October 20, 2013}}</ref> but the team also collected specimens of animals they encountered.<ref name="ls">{{cite web|url=http://www.livescience.com/39636-beautiful-new-snail.html|title=New See-Through Snail Discovered Deep Underground|author= Laura Poppick|date=September 13, 2013|publisher=LiveScience|accessdate=October 20, 2013}}</ref> The cave system has two entrances, the Lukina jama and the Trojama caves (''jama'' means "pit" in [[Croatian language|Croatian]]). Lukina jama is situated about {{convert|37|m|ft|abbr=on}} lower on the mountain slopes than Trojama.<ref name=Weigand/> It was named after the caver Ozren Lukic, who was killed in the Velebit mountains while serving as a Croatian soldier in the [[Croatian War of Independence]]. Lukina jama and Trojama are connected to each other underground at a depth of {{convert|558|m|ft|abbr=on}} from the entrance of Lukina jama ({{convert|595|m|ft|abbr=on}} if measured from the entrance of Trojama).<ref name="lukina"/> The cave system is unusual for containing three different [[microclimate|microclimatic]] layers which makes it extremely interesting in terms of [[biodiversity]] to scientists.<ref name="ls"/> The first {{convert|200|m|ft|abbr=on}} of the cave system's entrance is permanently covered in thick layers of snow and ice and has an average air temperature of {{convert|1|°C|°F|abbr=on}}.<ref name=Weigand/><ref name="lukina"/> The cave system progressively becomes warmer in deeper areas, with an average air temperature of {{convert|2|°C|°F|abbr=on}} in the middle part and {{convert|4|°C|°F|abbr=on}} at the bottom.<ref name="ls"/>

Empty shells of ''Zospeum tholussum'' were encountered by the team beginning at a depth of {{convert|743|m|ft|abbr=on}} and down to the lake at the bottom of the cave, which is about {{convert|1392|m|ft|abbr=on}} beneath the Trojama cave entrance. The shells were usually found embedded in layers of mud, with an appearance described as a "grazing-labyrinth-like" structure. The team collected eight empty shells over a period of several days.<ref name=Weigand/> They also recovered a single live specimen of ''Zospeum tholussum'' from an unnamed large chamber at a depth of about {{convert|980|m|ft|abbr=on}}. The chamber was about {{convert|65|m|ft|abbr=on}} long and {{convert|70|m|ft|abbr=on}} wide. The chamber substrate was composed mainly of rocks and sand. A small temporal stream was also present near the area. The air temperature in the chamber was about {{convert|3.3|to|3.5|°C|°F|abbr=on}} with an air humidity of 100%. The water temperature of the stream was about {{convert|5.1|°C|°F|abbr=on}}.<ref name=Weigand/>

==Taxonomy==
[[File:Holotype and paratypes of Zospeum tholussum - SubtBiol-011-045-g002.jpg|thumb|right|upright|The [[holotype]] (surrounded by solid lines) and five [[paratype]]s (surrounded by broken lines) of ''Zospeum tholussum'']]
''Zospeum tholussum'' was formally described by the German [[taxonomist]] Alexander M. Weigand in 2013, based on the specimens the caving expedition recovered. The [[specific name (zoology)|specific name]] is derived from [[Latin]] ''tholus'', meaning [[dome]] or [[cupola]], referring to the distinctive dome-like shape of the second whorl of the shell. The nine [[type specimen]]s are currently deposited in the [[Naturmuseum Senckenberg|Forschungsinstitut und Naturmuseum Senckenberg]] in [[Frankfurt am Main]], [[Germany]] (museum voucher SMF 341633). The eight empty shells were used as the [[paratype]]s by Weigand, one of which was broken open to investigate the central column of the shell. While the single living specimen was designated as the [[holotype]].<ref name=Weigand/> ''Zospeum tholussum'' is classified under the [[genus]] ''[[Zospeum]]'' of the [[subfamily (biology)|subfamily]] [[Carychiinae]] in the hollow-shelled snail [[family (biology)|family]], [[Ellobiidae]].<ref name="worms">{{cite WoRMS|author=Philippe Bouchet|year=2013|id=739921 |title=''Zospeum tholussum'' Weigand, 2013 |db=mollusca|accessdate=October 20, 2013}}</ref> Although some authors (including Weigand) consider Carychiinae to be a separate family, Carychiidae.<ref name="weigand2">{{cite journal|author=Alexander M. Weigand, Adrienne Jochum, Rajko Slapnik, Jan Schnitzler, Eugenia Zarza & Annette Klussmann-Kolb|year=2013|title=Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses|journal=BMC Evolutionary Biology|volume=13|pages=18|doi=10.1186/1471-2148-13-18|url=http://www.biomedcentral.com/1471-2148/13/18}}</ref>

Weigand identified ''Zospeum tholussum'' as a new species based on the [[conchology|morphology of the shell]]s as well as [[Molecular genetics|molecular genetic]] data recovered from the single living specimen. The [[DNA barcode]] of the ''Zospeum tholussum'' [[holotype]], when compared with other DNA barcodes of ''Zospeum'' species, shows its lowest interspecific genetic distance to ''[[Zospeum pretneri]]''. This result is well above the barcoding gap of 3.2 % for Carychiinae, which is suitable to separate between species (> 3.2%, interspecific) and within species genetic diversity (< 3.2%, intraspecific) in ''Zospeum''.<ref name=Weigand/> ''Zospeum tholussum'' closely resemble ''[[Zospeum amoenum]]'' morphologically, but can be readily distinguished by the dome-like shape of their second whorls and by the presence of a slight fold in the central column of the shells. They can also be readily separated by means of their DNA barcodes (11.7% to 12.1% [[Genetic distance|genetic]] [[Models of DNA evolution|<math>p</math>-distance]] between the two species).<ref name=Weigand/>

Lukina jama–Trojama also contains a second yet undescribed species of ''Zospeum'', also recovered by the 2010 expedition. It can be distinguished from ''Zospeum tholussum'' by its general shell shape, a more prominent fold in the shell central column, the absence of the dome-like structure on the second whorl, and the presence of a tooth. However, no living specimens of this species were recovered, so DNA barcodes could not be obtained to determine its exact taxonomic relationship with ''Zospeum tholussum''.<ref name=Weigand/>

==Description==
[[File:Columellar fold views of Zospeum tholussum - SubtBiol-011-045-g003.jpg|thumb|left|A specimen of ''Zospeum tholussum'' broken open and rotated clockwise to show the [[Columella (gastropod)|columellar]] fold]]
''Zospeum tholussum'' are microscopic snails (microgastropods) with a shell height of only about {{convert|1.41|to|1.81|mm|in|abbr=on}} and a shell width of about {{convert|0.93|to|1.12|mm|in|abbr=on}}. The shell height to width ratio is between 1.34 to 1.62. They possess about five to six whorls. The second whorl is distinctive for being greatly enlarged and dome-like in shape, with a height of about {{fraction|2|3}} to {{fraction|5|6}} of the heights of the third and fourth whorls combined.<ref name=Weigand/>

The opening of the shell ([[Aperture (mollusc)|aperture]]) is about {{convert|0.44|to|0.54|mm|in|abbr=on}} in height and {{convert|0.38|to|0.46|mm|in|abbr=on}} in width, with an aperture height to width ratio between 1.05 to 1.30. It is devoid of teeth. The central column of the shell (the [[Columella (gastropod)|columella]]) possesses a weakly developed columellar fold.<ref name=Weigand/> The shells of the collected specimens of ''Zospeum tholussum'' have a moderately variable morphology between individuals in the species. They are typically very thin and fragile with a smooth surface. Fresh shells or those of living specimens are translucent, while older ones are more opaque, with a milky white color.<ref name=Weigand/>

==Ecology==
[[File:The Lukina Jama–Trojama cave system - SubtBiol-011-045-g001.jpg|thumb|right|A 3D cross-section of the [[Lukina jama–Trojama]] [[cave system]] in the[[Velebit]] mountains of [[Croatia]]. The collection sites ('''1''') of the shells and the single living specimen ('''2''') are indicated, along with pictures by Jana Bedek of the HBSD.<ref name=Weigand/>]]
Like all members of the genus ''Zospeum'', ''Zospeum tholussum'' are completely blind. Because of this and their lack of pigmentation, they are considered to be true cave-dwelling organisms ([[eutroglobiont]]s).<ref name="ibt"/> Very little is known about their biology, but members of the genus ''Zospeum'' are known to prefer muddy to permanently wet subterranean microhabitats. They are generally found along the drainage systems of caves.<ref name=Weigand/>

Due to their tiny shell sizes,<ref name="weigand2"/> ''Zospeum'' species are extremely slow-moving snails. In a week's time, they may only move a few millimeters or centimeters while grazing, usually in small circles around a given point.<ref name="ls"/> Because of their proximity to bodies of water and their preference for habitats with a mud substrate, Weigand and colleagues (2013) have proposed that the primary mode of dispersal of ''Zospeum'' species may be passive, either by being carried along in running water or through the activities of larger animals like cave [[bat]]s or [[Cricket (insect)|cricket]]s.<ref name=Weigand/><ref name="weigand2"/>

==Distribution==
''Zospeum tholussum'' are currently only known from the Lukina jama–Trojama cave system of Croatia. Its distribution range is within the larger distribution range of the morphologically similar ''Zospeum amoenum'' (which is found in caves in the [[Balkans#Western Balkans|Western Balkans]] in northern [[Slovenia]], western Croatia, [[Bosnia and Herzegovina]], and [[Montenegro]]).<ref name=Weigand/> Since ''Zospeum'' species with large inferred distribution ranges are known to actually also contain morphologically similar and unrecognized [[cryptic species]], Weigand postulated that some early records of ''Zospeum amoenum'' may have actually been specimens of ''Zospeum tholussum''.<ref name=Weigand/>

==See also==
*[[List of troglobites]]
*''[[Zospeum biscaiense]]''

==References==
{{reflist|40em}}

==External links==
{{Commonscat|Zospeum tholussum|''Zospeum tholussum''}}
{{Wikispecies|''Zospeum tholussum''}}
*{{cite web|url=http://public.carnet.hr/speleo/lukina2010/index-en.html|title=Speleological expedition "Lukina jama 2010"|author=Luka Mudronja, Dalibor Paar & Marko Lukić|others=Translated by Dina Kovač|date=April 24, 2013|publisher=Croatian Speleological Server}}

{{DEFAULTSORT:Zospeum Tholussum}}
[[Category:Ellobiidae]]
[[Category:Endemic fauna of Croatia]]
[[Category:Animals described in 2013]]

Gauge Vector-Tensor gravity - Revision history

en>Gaba p: Added {{merge to}} tag to article (TW)