Count Francois (in English Francis) Louis de Laporte de Castelnau, a French consular official and naturalist, studied natural history in Paris and published a description of a collection of coleoptera as early as 1829, followed by a publication on the order Hemiptera in 1832. From 1837 to 1841 he led a scientific expedition to Canada and the United States. He collected in Florida around 1838, resulting in three papers on his travels there and on the geography of Florida. During 1843-1847 he directed a French expedition to South America and wrote several works (in French) describing its results. These dealt with the colleoptera (1851), crustaceans and arachnids (1851), geological observations during a traverse from Rio de Janeiro to Lima (1852); the geography of South America (1854); Inca antiquities (1854); and the animals (including the fishes) of the continent (1855-1859).
In 1848 de Castelnau was appointed French consul in Siam (now Thailand), and during 1856 and 1857 held a similar position in the Cape Colony. During this time he undertook a journey to Algoa Bay and the eastern border regions. He wrote a letter on the geology of the border districts, as well as a report to the French Minister of Foreign Affairs on an earthquake experienced at the Cape. Both were published in Comptes Rendus Hebdomadaires des Seances de l'Academy des Sciences in 1858, while the first also appeared in The Geologist (London) in the same year. In Cape Town he helped the director of the South African Museum, E.L. Layard* to revise the museum's reptile collection, and Layard described him as "a most skillful herpetologist". He also wrote a treatise on South African fishes, Memoir sur les poissons de l'Afrique australe (Paris, 1861, 78p), in which he described 21 freshwater species from the Cape and as far north as the Okavango Delta, including the tiger fish (Hydrocynus vittatus), the Eastern Cape rocky (Sandelia bainsii), and a specimen later shown to have been a goldfish! He also collected plants, taking most of his specimens to Paris.
From 1862 to his death in 1880 de Castelnau resided in Melbourne, Australia, where he became consul-general for France in 1864. In 1873 he wrote a paper for the International Exhibition in London on the edible fishes of Victoria. Other papers by him were published in the Proceedings of the Royal Society of Victoria, including "Notes on Australian Coleoptera" (1867) and "Contribution to the Ichthyology of Australia" (1873). Altogether he wrote about ninety books and papers, initially under the name Laporte or Delaporte, but later as Castelnau. The genus Laportea (tropical stinging tree) was named in his honour, as were many insect and fish species.