Research Article |
Corresponding author: Barna Páll-Gergely ( pallgergely2@gmail.com ) Academic editor: Martin Haase
© 2020 Barna Páll-Gergely, Thomas A. Neubauer.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Páll-Gergely B, Neubauer TA (2020) The value of a single character: the Paleogene European land snail Ferussina Grateloup, 1827 is likely a cyclophorid (Gastropoda, Caenogastropoda). ZooKeys 918: 29-40. https://doi.org/10.3897/zookeys.918.50135
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Ferussina Grateloup, 1827 is a European Paleogene land snail genus, which is currently classified in its own family, the Ferussinidae Wenz, 1923 (1915), in the superfamily Cyclophoroidea. The shell of this genus is remarkable by its last quarter whorl turning towards the apex instead of away from it, which is an unusual trait in terrestrial snails. We show, however, that this trait has evolved at least nine times in terrestrial Eupulmonata and Caenogastropoda, and it does not justify distinction at the family level in any of the reported cases. This observation suggests the systematic position of Ferussina should not be based on the apexward-turning last quarter whorl alone but instead on the general morphology of the shell. As a result, we re-evaluate the systematic position of the Ferussinidae and treat it as a subfamily of the Cyclophoridae.
character evolution, Eocene, Oligocene, parallel evolution, terrestrial Gastropoda, unique trait
Ferussina Grateloup, 1827 (and its synonym Strophostoma Deshayes, 1828; see
Geographic and stratigraphic distribution of Ferussina in central and western Europe. Records that are questionable in terms of stratigraphic horizon or species identification are indicated with a question mark (see Suppl. material
In his catalogue of fossil non-marine gastropods,
Representatives of the genus Ferussina. A–C Ferussina anostomaeformis Grateloup, 1827, Gaas (Larrat), France, lower Oligocene; syntype, UBRG, Grateloup collection, no. 65-2-150 D Ferussina anostomaeformis, St-Paul-lès-Dax (Abesse, “Château”), France, upper Oligocene;
An “upright” turning last whorl (termed “anostomy” by
Abbreviations used:
While the apexward-turning last whorls are unique among fossil European land snails, we found this trait in a number of unrelated extant and fossil clades, including 12 pulmonate (
Summary of key information of extant land snail genera with apexward turning body whorl. In addition, we provide information on shell shape of relatives within the same family to assess the relevance of shape traits for systematic placement. Information derives from
Genera | Size (mm) | Shell shape without body whorl | Habitat | Geographic region | Shell shape of relatives |
---|---|---|---|---|---|
Boysia, Gyliotrachela, Hypselostoma | 2–4 | ovoid, conic | rock surfaces | Southeast Asia to Australia | ranging from ovoid and conic to lenticular and globular |
Campolaemus | 2 | ovoid | not rock-dwelling | Saint Helena | unknown (might be ovoid or depressed) |
Anostoma, Clinispira, Ringicella | 14–16 | obesely lenticular (depressed-globular), elongate-conical | not rock-dwelling (caves, under stones/logs) | Brazil | mostly high-spired |
Hendersoniella | 11–13 | flat | rock surfaces | Mexico | all high-spired |
Tonkinia | 4.3–5 | elliptical | not rock-dwelling | Vietnam | mostly high-spired |
Anostomopsis, Enneopsis, Strophostomella | 11–18 | cup-shaped, ovoid, depressed globular | unknown | Austria, Hungary, France | planispiral, lenticular, ovoid |
Anosycolus | 12 | conical | unknown, probably not rock-dwelling | Madagascar | conic, ovoid, high-spired |
Laotia | 2.2–4.4 | depressed globular | unknown, probably not rock-dwelling | Laos and Vietnam | mostly low-spired to conical |
Opisthostoma, Plectostoma | 1.0–3.7 | ovoid to depressed-globular | rock surfaces | Southeast Asia | ovoid to conic |
(1) Genera Boysia Pfeiffer, 1849, Gyliotrachela Tomlin, 1930, Hypselostoma Benson, 1856
Remarks. These genera were included in the family Hypselostomatidae by
(2) Genus Campolaemus Pilsbry, 1892
Remarks. This genus was classified in the Hypselostomatidae by
(3) Genera Anostoma Fischer von Waldheim, 1807, Clinispira Simone & Casati, 2013, Ringicella Gray, 1847
Remarks. Anostoma was classified in the tribe Odontostomini (Bulimulidae, Bulimulinae) by
(4) Genus Hendersoniella Dall, 1905
Remarks.
This genus was classified in the Urocoptidae, Holospirinae (
(5) Genus Tonkinia Mabille, 1887
Remarks. This genus was classified as a member of the Streptaxidae, Streptaxinae by
(6) Genera Anostomopsis Sandberger, 1871, Enneopsis Wenz, 1940, Strophostomella Fischer, 1883
Remarks. The three genera derive from upper Cretaceous (Coniacian–Maastrichtian) strata of Europe (Austria, Hungary, and France) and are currently classified in the fossil family Anostomopsidae with uncertain position in the Stylommatophora (
(1) Genus Anosycolus Fischer-Piette, C.P. Blanc, F. Blanc & Salvat, 1993
Remarks. This taxon was classified in the Hainesiidae by
(2) Genus Laotia Saurin, 1953
Remarks. This genus was classified in the Diplommatinidae by
(3) Genera Opisthostoma W.T. Blanford & H.F. Blanford, 1860, Plectostoma Adams, 1865
Remarks. Both are members of the Diplommatinidae (
The list above shows that shells with the last whorl turned apexward are present in numerous unrelated lineages of pulmonate and operculate terrestrial snails. In all cases, the species and genera with this peculiar shape have normally coiled relatives. Similarly, the fossil Ferussina certainly evolved from normally coiled ancestors, and we should not give too great importance to this trait when determining its systematic position. Moreover, the closest relatives of these genera are often species with high-spired shells. This suggests that we cannot exclude high-spired cyclophoroideans from the possible relatives of Ferussina.
We can exclude the Pomatiidae as possible relatives, as members of this family have calcareous opercula that are often found as fossils. No such opercula have been documented for Ferussina. The Cochlostomatinae, also with numerous extant and fossil members, are smaller than Ferussina and are characterized by high, conical shells, and some members have calcareous opercula (
The most probable group of relatives is the Cyclophoridae. Most members of this family have broadly conical shells similar to that of Ferussina, except for the apexwards turn of the last quarter whorl. Extant Cyclophoridae have non-calcareous opercula, which are not preserved as fossils. So far, 14 species of Cyclophoridae are known from the Cenozoic sedimentary record of Europe (W
Cyclophoridae are otherwise mostly restricted to south-eastern Asia, and the European fossils represent a rare exception of biogeographic affinity between both regions. Only a few other taxa that are widespread in East Asia today are also found in the European Cenozoic fossil record, such as Diplommatinidae, Strobilopsidae, and Pupinidae (e.g.
In summary, we suggest a revised systematic position of the genus Ferussina in the Cyclophoridae. Given the distinct biogeographic and stratigraphic setting and morphological differences to extant Cyclophoridae, we suggest to maintain the genus in a distinct subfamily, Ferussininae.
The extant genera with apexward-turning body whorl listed above inhabit various habitats, with about half of them being obligatory rock-dwellers, indicating that this peculiar trait can be developed under various environmental conditions. Ferussina lived in a period when the regions it occurred in central and western Europe (France, Switzerland, Germany, Austria, and northern Italy) were dominated by warm-temperate to subtropical evergreen forests (
We are grateful to Bruno Cahuzac, Laurent Charles, Anita Eschner, Pierre Lozouet, Hartmut Nordsieck, Emmanuel Robert, and Rodrigo Salvador for sending photos and/or providing valuable literature and information. Dietrich Kadolsky and Mathias Harzhauser are thanked for their constructive reviews. We are indebted to The Biodiversity Heritage Library for the multitude of rare literature made available to us (http://www.biodiversitylibrary.org). This study was supported by the MTA (Hungarian Academy of Sciences) Premium Post Doctorate Research Program granted to B. Páll-Gergely. T.A. Neubauer was supported by a DFG grant (no. NE 2268/2-1).
Table S1
Data type: occurrence data
Explanation note: Geographic and stratigraphic occurrence data for species of Ferussina. Provided are approximate GPS coordinates of the localities, alternative spellings of locality names, indications of type localities and literature.