Neohelice is found in the south-western Atlantic Ocean, from the Laguna Araruama in Rio de Janeiro state, Brazil to the Golfo San José (on the north side of the Valdes Peninsula in Patagonia, Argentina).

[2] The diet of Neohelice in the wild most consists of sediment, Spartina and plant-derived detritus.

[2] In 1918, Mary J. Rathbun redescribed the species under the modified name "Chasmagnathus granulata", which remained in occasional use along Dana's name until 2006, when Katushi Sakai, Michael Türkay and Si-Liang Yang revised the genera Helice and Chasmagnathus.

Much of the scientific research has focused on the species' tolerance of both fresh water and brine (euryhalinity) and its semiterrestrial habit.

[2] It has also been investigated for research into neurophysiology, neurobiology of learning and memory,[4] toxicology and ecosystem dynamics.