Photo of the day (82): Palaeotachea

These are photos of a shell of a snail from the genus Palaeotachea from the Early or Middle Miocene of the Pfaffenhofen district in Bavaria, Germany. I thank my friend and paleomalacologist Rodrigo B. Salvador who has kindly shared the following photos. Paleomalacologist is a biologist who study prehistoric molluscs.

The genus Palaeotachea belongs to the subfamily Helicinae, within the well known family Helicidae. All species of the genus Palaeotachea lived in the Early or in the Middle Miocene and all of them are extinct now. There are recognized at least 11 species within the genus. It was hypothetized that Palaeotachea species lived in habitats varying from from scrublands to humid woods. In the middle of the Middle Miocene something happened and all Palaeotachea species died out. Instead of them other species from the other genus – Megalotachea sylvestrina also from the family Helicidae – started to thrive.

This certain shell is possibly Palaeotachea silvana. That means it is an interesting species worth to know for everybody who is interested in Tertiary of Europe.

Palaeotachea

Apertural view of Palaeotachea. Photo by Rodrigo B. Salvador, CC-BY-4.0.

Palaeotachea

Apertural view of Palaeotachea. It is the previous image rotated to the main position. Photo by Rodrigo B. Salvador, CC-BY-4.0.

When will you rotate the image into the main or standard position like this, you can much more easily measure the width and the height of the shell. The width of this shell is about 21 mm.

Palaeotachea

Apical view of Palaeotachea. Photo by Rodrigo B. Salvador, CC-BY-4.0.

Palaeotachea

Apical view of Palaeotachea. It is just rotated the previous image. Photo by Rodrigo B. Salvador, CC-BY-4.0.

So what’s interesting in Palaeotachea silvana?

Palaeotachea silvana (Klein, 1853) is an extinct species, that has lived in Middle Miocene.

The specific name silvana is an adjective of the Latin word silva, that means forest or wood. Unfortunately I do not know why the author has chosen this specific name. It was described by physician of the German army (Generalstabsarzt, it is a second highest military rank for physicians in the army) and naturalist Adolf von Klein (1805–1891 or 1892) from Kingdom of Württemberg (now Baden-Württemberg in southwest Germany). The description was published in local journal Jahreshefte des Vereins für vaterländische Naturkunde in Württemberg that could be translated as Yearbook of the Association for Natural History in Württemberg. He described this species under the name Helix silvana in 1853. Later other names were used for this species: Cepaea silvana (Klein, 1853) and Megalotachea silvana (Klein, 1853). These names are considered as synonyms.

Helix crepidostoma Sandberger, 1872 is the type species of the genus Palaeotachea. But the Palaeotachea silvana can be considered as the most important species of the genus. Palaeotachea silvana is an index fossil. Index fossil is a species that is a common and widely distributed in a certain relatively short period. Palaeotachea silvana is an index fossil of Silvana Beds. It is also spelled Silvana-beds, and Silvanaschichten or Silvanakalk in German language. Silvana Beds got its name directly after this species. Palaeotachea silvana is most commonly found fossil in Silvana Beds. Silvana Beds’ range is from 15.8 to 13.8 myr (millions years ago). This means that range of Silvana Beds approximately correspond to older part of the Middle Miocene. Palaeotachea silvana is known at least from the following countries: Hungary, Austria, Baden-Württemberg in Germany and Bavaria in Germany.

The width is some shells of Palaeotachea silvana usually reach about 22 mm, but unusually big shells may have shell width up to 28 mm. There are sometimes visible by naked eye or under the UV light two or three bands on shells of Palaeotachea silvana, but this specimen has no bands. The shell has 4 – 4½ whorls. For other details about shell description see both works Salvador et al. 2015.

The mean annual temperature in the Central Europe in the Middle Miocene was about 19 °C. Yes, it was really hot those days.

References (sorted chronologically, newest first)

Höltke, O.; Salvador, R. B.; Rasser, M. W. 2018. Miocene continental gastropods from the southern margin of the Swabian Alb (Baden-Württemberg, SW Germany). Neues Jahrbuch fur Geologie und Palaontologie, Abhandlungen 287(1): 17–44. DOI: 10.1127/njgpa/2018/0704.

Salvador, R. B.; Höltke, O.; Rasser, M. W. 2018. Miocene continental gastropods from Dischingen, Germany. Palaeodiversity 11(1): 11–19. DOI: 10.18476/pale.11.a2.

Salvador, R. B.; Tütken, T.; Tomotani, B. M.; Berthold, C.; Rasser, M. W. 2018. Paleoecological and isotopic analysis of fossil continental mollusks of Sandelzhausen (Miocene, Germany). Paläontologische Zeitschrift 92(3): 395–409. DOI: 10.1007/s12542-017-0400-6.

Salvador, R. B. & Rasser, M. W. 2017. Fossil terrestrial and freshwater Gastropoda from the Early/Middle Miocene of Heuchlingen, Germany. Archiv für Molluskenkunde 146(2): 233–241. DOI: 10.1127/arch.moll/146/233-241.

Salvador, R. B.; Höltke, O.; Rasser, M. W. 2017. Fossil land and freshwater gastropods from the Miocene of Hohenmemmingen, Germany. Palaeodiversity 10: 41–48. DOI: 10.18476/pale.v10.a4.

Höltke, O.; Salvador, R. B.; Rasser, M. W. 2016. Paleobiogeography of Early/Middle Miocene terrestrial gastropods in Central Europe: an approach using similarity indices. Palaeogeography, Palaeoclimatology, Palaeoecology 461: 224–236. DOI: 10.1016/j.palaeo.2016.08.027.

Salvador, R. B. & Rasser, M. W. 2016. Fossil land and freshwater gastropods from the Middle Miocene of Bechingen and Daugendorf, southwestern Germany. Archiv für Molluskenkunde 145(1): 111–124. DOI: 10.1127/arch.moll/1869-0963/145/111-124.

Salvador, R. B. & Rasser, M. W. 2016. The fossil land and freshwater snails of Oggenhausen (Middle Miocene, Germany). Revista Brasileira de Paleontologia 19(1): 41–52. DOI: 10.4072/rbp.2016.1.04.

Salvador, R. B.; Höltke, O.; Rasser, M. W.; Kadolsky, D. 2016. Annotated type catalogue of the continental fossil gastropods in the Staatliches Museum für Naturkunde Stuttgart, Germany. Palaeodiversity 9: 15–70. DOI: 10.18476/pale.v9.a3.

Salvador, R. B.; Pippèrr, M.; Reichenbacher, B.; Rasser, M. W. 2016. Early Miocene continental gastropods from new localities of the Molasse Basin in southern Germany. Paläontologische Zeitschrift 90(3): 469–491. DOI: 10.1007/s12542-016-0291-y.

Salvador, R. B.; Prieto, J.; Mayr, C.; Rasser, M. W. 2016. New gastropod assemblages from the Early/Middle Miocene of Riedensheim and Adelschlag-Fasanerie, southern Germany. Neues Jahrbuch fur Geologie und Palaontologie, Abhandlungen 279(2): 127–154. DOI: 10.1127/njgpa/2016/0546.

Salvador, R. B.; Rasser, M. W.; Höltke, O. 2015. Fossil gastropods from Miocene Lake Randeck Maar and its hinterland (SW Germany). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 277(3): 251–273. DOI: 10.1127/njgpa/2015/0505.

Salvador, R. B.; Sach, V. J.; Valentas-romera, B. L. 2015. The fossil continental mollusks in the Upper Freshwater Molasse (Middle Miocene) of the districts of Biberach, Ravensburg and Neu-Ulm, Germany. Revista Brasileira de Paleontologia 18(2): 201–216. DOI: 10.4072/rbp.2015.2.02.

Klein A. v. 1853. Conchylien der Süßwasserkalkformation Württembergs. – Jahreshefte des Vereins für vaterländische Naturkunde in Württemberg, 9: 203–223. Plate 5, figure 2.

Advertisements