Hertlein’s Tryonia (Tryonia hertleini)

Hertlein’s Tryonia was described in 1956.

The shells reached sizes of about 0,25 to 0,32 cm in heigth. 

Hertlein’s Tryonia was restricted to a single locality near the terminus of the Río Casas Grandes drainage in Chihuahua, Mexico, close to the border to New Mexico, USA, which today is completely dry.  

The species is now considered extinct. [1][2]  

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References:

[1] Robert Hershler: Systematics of the North and Central American aquatic snail genus Tryonia (Rissooidea: Hydrobiidae) Smithsonian Contributions to Zoology 612: 1-53. 2001
[2] Robert Hershler; Hsiu-Ping Liu; J. Jerry Landeye: New species and records of springsnails (Caenogastropoda: Cochliopidae: Tryonia) from the Chihuahuan Desert (Mexico and United States), an imperiled biodiversity hotspot. Zootaxa 3001: 1-32. 2011

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edited: 02.05.2019