Oblong rocksnail

Leptoxis compacta

Leptoxis compacta (English oblong rocksnail ) is a Süßwasserschneckenart. It is endemic to the Cahaba River, a tributary of the Mobile River in the U.S. state of Alabama. She was no longer found in a period of more than 70 years and in 2000 formally declared extinct. It was only in May 2011, live specimens were rediscovered.

Features

The shell of Leptoxis compacta is ovoid to conical, smooth, thick-walled and yellowish- green. The thread rises at an obtuse angle and has five windings which are approximately flat. The Grundwindung that receives the body of the worm, on the other hand is far, only small wound and has three very dark bands. The penultimate convolution has only two dark bands, of which the bottom part or almost all of the slot ( suture ) is covered to the next turn. The topmost turn contributes only a hair-thin black line. The opening of the snail shell is relatively far off-white on the inside and also striped. The central spindle ( columella ) is strongly notched, the base is rounded uniformly and has no cavity. The width of the snail shell is approximately 10 mm and the height about 15 mm. The height of the opening is about 7.5 mm.

Most of the 2011 found wild specimens had a purple pigmentation at the notch of the columella, while this trait in the offspring, which were later mounted in captivity, could not be observed. Juvenile Leptoxis compacta carry on the main winding a small punch ( Carina ), which is lost in adult individuals.

The body surface is yellow with black speckles. In the middle of the trunk and on both eyes black run pigmented bands. The band pattern is identical to the ampla of occurring at the same location Leptoxis. The staining pattern and the presence of either eye socket ( peduncle ) differ Leptoxis compacta of the also occurring at the same location snails of the genus Pleurocera, Leptoxis compacta resemble conchologisch ( from the shell -wise) the most.

Way of life

Leptoxis compacta located on the upstream side of sandbanks.

The female specimens of Leptoxis compacta submitted within three days after transfer to the captivity 0.3 mm by measuring eggs singly or in short rows from. The average length of Eilinien was 1.57 eggs, maximum 3 eggs were counted in a line. No more eggs were laid at water temperatures above 29 ° C.

Discovery history, distribution and hazard

The first description of Leptoxis compacta was made in 1854 by John Gould Anthony under the name Melania compacta.

The previously documented distribution area extended from the lower reaches of the Buck Creek in the south of the Valley -and- Ridge Zone of the Appalachians up to Centerville in Alabama. The strongest proliferation was found in the area of ​​Lily Shoals sand banks in the middle reaches of the Cahaba River. The cause of the decrease from 1935 documented the population of Leptoxis compacta is unknown. In addition to the originally already small habitat waste of regional mines and the metropolitan area of Birmingham are regarded as the most likely cause. The last documented Fund dated to the year 1933. Through a series of systematic studies of the river in 1992, 2005 and 2008 Leptoxis compacta could not be detected. Already in 2000, was declared extinct Leptoxis compacta of the International Union for Conservation of Nature and Natural Resources ( IUCN). She was the only extinct endemic species of the family of Pleuroceridae in the Cahaba River.

Copies in a very short section of the Cahaba River near the inlet of the Shades Creek again - only in May 2011, as part of an expedition to capture the biodiversity of the worm in the catchment area of the Mobile River in the U.S. state of Alabama - after almost 80 years without finding Leptoxis compacta found. This rediscovery was published in August 2012 in PLoS ONE. The authors in their work to the conclusion that the locally very limited existence of this kind they threatened to die out finally with a single environmental catastrophe, and discuss whether it is possible by increasing the snails in the laboratory and Resettlement in the entire native range improve the chances of survival.

The scientific publication of rediscovery was received from journalistic or popular scientific side, particularly in relation to the general extinction of species.