Mary Jane Longstaff, FLS, FGS (née Donald; 27 August 1855 – 19 January 1935) was a British malacologist, specialising in fossil gastropods of the Palaeozoic.
She was the eldest child of Matthew Hodgson Donald, a prominent local industrialist, and his wife Henrietta Maria Roper.
[1] Although she never had any formal scientific education, she was interested in nature from a very early age, and particularly in snails and other land and freshwater molluscs.
[4] As a woman, Donald could not be employed by or formally affiliated with any particular museum, limiting her access to fossil collections and scientific communication.
[1][6] Based on her collections in the tropics, she published a number of papers and appendices to her husband's books, most notably one on the freshwater and land molluscs of the southern Sudan.