Viviparus glacialis

Taxobox
name = "Viviparus glacialis"

---

image_width = 225px
status =
regnum = Animalia
phylum = Mollusca
classis = Gastropoda
ordo = Architaenioglossa
superfamilia = Ampullarioidea
familia = Viviparidae
genus = "Viviparus"
species = "V. glacialis"
binomial = "Viviparus glacialis"
binomial_authority = (S.V. Wood, 1872) [en Aut|Wood, S.V., 1872-1874. "Supplement to the monograph of the Crag Mollusca, or, description of shells from the Middle and Upper Tertiaries of the east of England, 3. Univalves and bivalves". Monograph Palaeontographical Society of London, 31 + 99 pp., pls 1-7 (1872); 99-231, pls 8-21 (1874).]
synonyms = "Paludina glacialis" Wood, 1872

"Viviparus glacialis" is an extinct species of the freshwater gastropods in the Viviparidae family.

Description

hell characteristics

An elongated slim, rather thick walled shell with approximately 6 ¼ flat whorls which are separated by a shallow suture. The apex is blunt. The aperture is slantingly oval and weakly angulated at the top. The peristome is simple, not thickened and not continuous. There is a narrow umbilicus that may be covered with callus. The surface of the shell is smooth and glossy and bears regular growing lines. Under a magnification of c. 50× a sculpture of fine spiral grooves can be observed. These 'grooves' are composed of densely spaced tiny holes. In most cases the periostracum has not been preserved but if still present this has a light brown to black color. A color pattern is unknown.

Dimensions of the shell

*Height: c. 24 millimeters
*Width: c. 13.5 millimeters

Animal

Nothing is known about the anatomy of the animal.

Reproduction and life span

Although all Viviparidae are ovoviviparous, nothing is known about the reproduction stratigy of this species. Based upon counting of 'annual rings' this species may reach an age of at least 12 years.

Habitat

According to the ecological preferences of extant species co-occurring with "Viviparus glacialis" and the sedimentary facies in which these are found, the species favours quiet parts of a fluvial environment. From the same data it may be concluded that the species can endure a slight increase of salinity.

Area

The species is only known from the Netherlands [nl Aut|Gittenberger, E., Janssen, A.W., Kuijper, W.J., Kuiper, J.G.J., Meijer, T., Velde, G. van der & Vries, J.N. de, 1998. "De Nederlandse zoetwatermollusken. Recente en fossiele weekdieren uit zoet en brak water" Nederlandse Fauna 2. Nationaal Natuurhistorisch Museum Naturalis, KNNV Uitgeverij & EIS-Nederland, Leiden, 288 pp.] and the United Kingdom. From the United Kingdom only 6 specimens are known (among which is the holotype). The specimens have been found in the Weybourn Crag, which has an estuarine facies. In the Netherlands the species has been only found in deposits of the River Rhine. It is known from clay pits in the surroundings of the village of Tegelen (Province of Limburg) and in several dozens of boreholes, especially in the Southern part of the Netherlands. The species may occasionally occur there in very high numbers.

Fossil occurrence

In the Netherlands known from interglacial deposits with a Tiglian and Pretiglian age. In the United Kingdom only present in the late Tiglian.

'Guide fossil'

"Viviparus glacialis" is, although already present in the Pretiglian, considered as a guide fossil for the Tiglian.

References

* Aut|Gibbard, P.L., West, R.G., Zagwijn, W.H., Balson, P.S., Burger, A.W., Funnell, B.M., Jeffery, D.H., De Jong, J., van Kolfschoten, T., Lister, A.M., Meijer, T., Norton, P.E.P., Preece, R.C., Rose, J., Stuart, A.J., Whiteman, C.A., Zalasiewicz, J.A., 1991. "Early and Early Middle Pleistocene correlations in the southern North Sea Basin." Quaternary Science Reviews 10: 23-52.
* Aut|Meijer, T., 1990a. "Notes on Quaternary freshwater mollusca of the Netherlands, with descriptions of some new species." Mededelingen van de Werkgroep voor Tertiaire en Kwartaire Geologie, 26(1989): 145-181.
* Aut|Meijer, T., Preece, R.C., 1995. "Malacological evidence relating to the insularity of the British Isles during the Quaternary." In Island Britain: a Quaternary perspective. Preece, R.C. (ed.) Geological Society Special Publication No. 96: 89-110.