Vallonia eiapopeia
| Vallonia eiapopeia | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Turolium | ||||||||||||
| 9 to 4.7 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Vallonia eiapopeia | ||||||||||||
| Gerber , 1996 |
Vallonia eiapopeia was a terrestrial snail species from the family of grass snails (Valloniidae). The species was first described in 1996 on the basis of fossil cases from the Turolium (Upper Neogene )found in China. For the choice of the unusual name, the first describer Jochen Gerber gave thefollowing explanation: "meaningless sound word, which is used especially in lullaby and lullaby".
features
The thin-walled housings are small and almost disc-shaped, the apex rises only slightly above the last passage. The diameter is 2 to 2.2 mm, the height varies from 0.95 to 1.1 mm. The protoconch comprises 1⅛ to 1¼ of the entire 3⅛ to 3¼ whorls. These are separated from each other by deep to very deep seams. The circumferences of the Teleoconch have narrow ribs, which are thread-like to wedge-shaped and moderately densely arranged in cross-section, on different housings they can protrude to different degrees. In every space between the ribs there are around three clear and even growth strips.
The whorls increase moderately quickly and evenly up to the mouth, in cross-section they encompass only a little, only the last whorl is evenly rounded along the periphery in the center of the wharf. The moderately wide, round and concentric umbilicus does not take up quite ⅓ of the maximum housing diameter and increases evenly until the end. The last passage in profile is initially mostly horizontal, occasionally in a straight line slightly downwards, towards the end or just before the mouth it kinks sharply downwards.
The mouth, which is strongly tilted against the axis of the housing, is almost circular in plan view. The insertions connected by a clearly pronounced, indented callus are very close to one another. Inside the mouth has an annular, stepped, moderately thickened lip; there is usually a shallow furrow between it and the edge of the mouth. The edge of the mouth is only slightly widened at the top, and clearly and very quickly widened outside and especially at the bottom.
Stratigraphy, geographic distribution and habitat
Vallonia eiapopeia was found in zone MN 13 of the Turolium ; the find comes from Ertemte, Huade District , Inner Mongolia (China). The Turolian is today correlated with the upper part of the chronostratigraphic stage of the Messinian (Upper Miocene ) and the basal Zancleum (Lower Pliocene ). So far only five specimens have been found, all of which originate from the type locality and the Stratum typicum .
There she found herself socialized with the relative Vallonia patens tralala . Using numerous vertebrate fossils that were also found, a picture of the habitat could be drawn. According to this, it was the area around a freshwater lake with diverse, hygrophilic vegetation. This consisted of partly tall trees, bushes and a lush herbaceous vegetation layer on the lake shore. This wet bank landscape was in turn surrounded by a dry steppe landscape . Similar habitats are still inhabited today by other closely related Vallonia species ( Vallonia patens , Vallonia kamtschatica , Vallonia pulchellula , Vallonia tokunagai ) in wetter regions east and northeast of the site.
Systematics and nomenclature
The species was first described in 1996 by Jochen Gerber as part of his revision of the genus Vallonia . The first description was based on collections made by Volker Fahlbusch and Gerhard Storch in 1980 at the type locality. It is considered to be related to the also Upper Miocene, western Palearctic Vallonia subcyclophorella .
The relation of the species name to the species is unclear, but is derived from the German "eiapopeia" as "meaningless sound word, which is used especially in sleep and lullabies". In the same text Gerber described other species with such unusual names, which, however, are only available to speakers of the German language.
proof
- ↑ a b c d e f Jochen Gerber: Revision of the genus “Vallonia” Risso 1826 (Mollusca: Gastropoda: Valloniidae). In: Schriften zur Malakozoologie 8, pp. 144–145
- ↑ Volker Fahlbusch, Zhuding Qiu and Gerhard Storch: The Neogene mammalian faunas of Ertemte and Harr Obo in Nei Mongol, China. 1. Report on field work in 1980 and preliminary results. Scientia Sinica, (B) 26: 205-224, Beijing 1983 ISSN 0253-5823