Notodiscus hookeri

[1] The specific name hookeri is in honor of English botanist Joseph Dalton Hooker, who collected this snail during the Antarctic expedition led by James Clark Ross.

testá mediocriter umbilicatá, orbuculari-depressá, sordidè olivaceá, subirrigulariter rugoso-striatá; spirá subplanulatá, suturis impressis; anfractibus quatuor, convexis; aperturá lunato-circulari, labro simplici.

Shell moderately umbilicated, orbicularly depressed, dull olive, rather irregularly roughly striated; spire rather flat, with sutures impressed; whorls four, convex; aperture lunar-circular, lip simple.

A small depressed species collected by Dr. Hooker in the Antarctic Expedition of the Erebus and Terror, peculiarly characterized by the sombre olive-horny coating of Paludina and Ampullaria.Henry Augustus Pilsbry classified this species as Helix hookeri in 1887[3] or within the genus Amphidoxa as Amphidoxa hookeri within the family Endodontidae in 1894.

[2] Their study was the first to demonstrate that gastropod shell micro structure responds to environmental heterogeneity, leading to the formation of ecophenotypes.

[2] This snail live in relatively simple ecosystems, that is caused by harsh environmental conditions on subantarctic islands.

[8] The soil is known to be a nutrient resource for Notodiscus hookeri, since this species has been found to significantly increase calcium release in solutions derived from plant litter.

[2] Notodiscus hookeri exclusively feeds on lichens such as Orceolina kerguelensis, Usnea taylorii and Pseudocyphellaria crocata.

Apertural view of a shell of Notodiscus hookeri .
SEM image of the shell micro-scale structure of OL-ecophenotype Notodiscus hookeri . The round white dot marks the outer periostracum . The almost vertical white line shows the organic layer. The thick white line is the innermost mineralised layer. Scale bar is 10 μm.
SEM image of the shell structure of OL-ecophenotype Notodiscus hookeri . The round white dot marks the outer periostracum. The double white line is a thick organic layer. The thick white line is the innermost mineralised layer. Scale bar is 10 μm.
Digestive system of Notodiscus hookeri