Balea sarsii

At the beginning of the 21st century it was realised by Hartmut Nordsieck and Theo Ripken that populations of Balea from Portugal were of two morphologial types. One species was the widespread Balea perversa and for the other they disinterred an old name Balea heydeni von Maltzan, 1881, originally described from Portugal. Shortly afterwards another clue came from a DNA sequence from a British sample of Balea, which was distinct from sequences from elsewhere in mainland Europe and closer to a species from the Azores. In 2006, information was collated by Gittenberger et al., who designated a lectotype for B. heydeni, now in the Paris museum.{{cite journal |last1=Gittenberger |first1=E. |last2=Preece |first2=R.C. |last3=Ripken |first3=T.E.J. |title=Balea heydeni von Maltzan, 1881 (Pulmonata: Clausiliidae): an overlooked but widely distributed European species |journal=Journal of Conchology |date=2006 |volume=39 |issue=2 |pages=145–150.}}

However, in 2010 von Proschwitz argued that a species described in 1847 from Norway, Balea sarsii, was the same as B. heydeni and that the former name should be used because it is the older. The evidence was that this species was found at the implied type locality of B. sarsii (Florø in Sogn og Fjordane County), where M. Sars has been supposed to have collected the specimens used in the species description. Subsequently, Bank{{cite journal |last1=Bank |first1=R.A. |title=Authorships and publication dates in malacology: some notes on the 2011 French checklist of Welter-Schultes & al. |journal=Mitteilungen der Deutschen Malakozoologischen Gesellschaft |date=2011 |volume=86 |pages=13–24 |url=http://www.dmg.mollusca.de/images/mitteilungen_dmg/mitteilungen086/mitt-086_009-024_bank-authorized.pdf}} argued that the original B. sarsii could just as easily have been B. perversa, which is much commoner in Norway. "Norway" was the only explicit specification of the type locality in the species description. In that case B. sarsii would be a junior synonym of B. perversa, and the other species should be called B. heydeni.

The dispute is unresolved: for instance Welter-Schultes' identification guide{{cite book |last1=Welter-Schultes |first1=F. |title=European non-marine molluscs: a guide for species identification |date=2012 |publisher=Planet Poster Editions |location=Göttingen |isbn=9783933922755}} uses B. sarsii, but MolluscaBase{{cite web |last1=((MolluscaBase Editors)) |title=Balea heydeni Maltzan, 1881 |url=https://www.molluscabase.org/aphia.php?p=taxdetails&id=1000826 |publisher=Flanders Marine Institute |access-date=6 July 2024}} prefers B. heydeni, as does the 2020 British List.{{cite web |last1=Anderson |first1=R. |last2=Rowson |first2=B. |title=Annotated list of the non-marine Mollusca of Britain and Ireland [2020 edition] |url=https://conchsoc.org/sites/default/files/Ben%20Rowson/British_revised_NMList_2020%20(26%20Nov%202020).pdf |publisher=Conchological Society of Great Britain and Ireland |access-date=6 July 2024}}

Bank also argued why the name Balea lucifuga applies to B. perversa, even though Bourguignat was applying it to B. sarsii when he made the name available in 1857. Welter-Schultes{{cite web |last1=Welter Schultes |first1=F. |title=lucifuga Bourguignat, 1857 described in Balea |url= http://www.animalbase.uni-goettingen.de |website=AnimalBase |publisher=University of Göttingen |access-date=11 July 2024}} has disagreed, implying that the name B. lucifuga would have priority over B. heydeni if B. sarsii were rejected.

The specific name sarsii honours Norwegian biologist Michael Sars. The name heydeni commemorates the German naturalist Lucas Friedrich Julius Dominikus von Heyden.

This species is known to occur in:

• Portugal both mainland and the Atlantic Islands
• northwestern and northern coastal regions of Spain{{cite journal |last1=Ruiz Cobo |first1=J.R. |last2=Quiñonero Salgado |first2=S. |title=Presencia de Balea heydeni von Maltzan, 1881 (Gastropoda: Clausiliidae) en Cantabria |journal=Spira |date=2016 |volume=6 |pages=91–93}}
• coastal parts of France
• coastal parts of Belgium
• coastal parts of the Netherlands
• Great Britain
• Ireland
• one coastal site in Denmark: Møns Klint
• west coast of Sweden
• Norway: Hordaland County and Sogn og Fjordane County

Balea sarsii has an Atlantic distribution. In Britain and Ireland it is the commoner of the two Balea species, occurring also inland. A 2010 revision of Balea material from Sweden and Norway revealed two localities for B. sarsii from the Swedish west coast (the Island of Vinga outside Göteborg and the island Storön in the archipelago of Väderöarna in the province of Bohuslän). The species is known from six Norwegian localities, of which five are situated in Hordaland County. It is considered a very rare species in Norway, because only sixteen Norwegian specimens have been found, among thousands of B. perversa.

The type locality of B. sarsii has been inferred to be Florø in Sogn og Fjordane County, the former home of M. Sars, who provided the specimens used in the species description. However, Sars had left Florø seven years before Pfeiffer published his description.{{cite journal |last1=Oug |first1=E. |last2=Bakken |first2=T. |last3=Kongsrud |first3=J.A. |title=Original specimens and type localities of early described polychaete species (Annelida) from Norway, with particular attention to species described by O.F. Müller and M. Sars |journal=Memoirs of Museum Victoria |date=2014 |volume=71 |pages=217–236}} This states explicitly only Norway as the locality. Florø is the northernmost known locality of B. sarsii.

If the correct name for this species is considered to be B. heydeni, the type locality is Sintra in Portugal, following the designation of a lectotype from that locality.

File:Balea sarsii shell 2.png

Like with most other species in the family Clausiliidae, the shells of Balea species are sinistral (left-handed) in their coiling and much taller than wide. At first glance, adult B. sarsii look like juveniles of some other clausiliid species, because this species lacks the prominent apertural structures that typically develop in clausiliid adults.

The most reliable distinction from B. perversa is that the first whorls of B. sarsii increase in diameter more rapidly, so that the appearance is conical, whereas these whorls in B. perversa are more like a cylinder. The shell of B. sarsii is broader and yellowish rather than darker brownish. The shell surface sculpture has wrinkled coarse growth lines rather than the finer and more regular riblets in B. perversa. A weak, parietal denticle may be present in B. perversa, but not in B. sarsii.

Balea sarsii sometimes co-occurs with B. perversa. Such syntopic occurrences are not uncommon in various parts of the distribution area, and probably both species have very similar ecologies. Balea species are rarely found on the ground, but rather on tree trunks and rocks; they are typically found in the crevices of bark. They eat lichens, a consequence of which is that air pollution seems to have caused a range reduction in Britain.{{cite book |last1=Kerney |first1=M. P. |title=Atlas of the land and freshwater molluscs of Britain and Ireland |date=1999 |publisher=Harley Books |location=Colchester, Essex, England |isbn=0946589488}}

This article incorporates CC-BY-3.0 text from the reference{{cite journal |last1=von Proschwitz |first1=Ted |title=Three land-snail species new to the Norwegian fauna: Pupilla pratensis (Clessin, 1871), Vertigo ultimathule von Proschwitz, 2007 and Balea sarsii Philippi, 1847 [= B. heydeni von Maltzan, 1881] |journal=Fauna Norvegica |date=2010 |volume=30 |pages=13–19 |doi=10.5324/fn.v30i0.628|doi-access=free }}

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{{commons category|Balea sarsii}}

• [http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=5372 Balea sarsii] at Animalbase

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Category:Clausiliidae

Category:Molluscs of Europe

Category:Gastropods described in 1847

Category:Taxobox binomials not recognized by IUCN