Astacoides - Taxonomic History

Taxonomic History

In 1839, the French explorer-naturalist Justin Goudot returned from an expedition to Madagascar bearing specimens of a crayfish he had collected there. He gave some of the material to the Muséum national d'histoire naturelle in Paris and some to Félix Édouard Guérin-Méneville. Both Guérin-Méneville and, at the museum, Henri Milne-Edwards and Jean Victoire Audouin wrote papers describing the new species, with the name Astacoides Goudotii Guérin, 1839 published on 29 April, and Astacus madagascarensis Milne-Edwards & Audouin, 1839 published on May 9. Some years later, and apparently unaware of the two French descriptions, Charles Spence Bate published what he thought was the first account of Madagascan crayfish. He had been brought specimens by J. Caldwell, and described them in 1865 under the name Astacus Caldwelli Bate, 1865. By the end of the 19th century, scientists had settled on the name Astacus madagascarensis, treating the others as synonyms, and to preserve nomeclatural stability, the name A. goudotii was suppressed by the International Commission on Zoological Nomenclature in 1958.

The next new taxon to be described was the variety betsileoensis described by Georges Petit in 1923. In 1927, he divided the Madagascan crayfish into the "macrophthalmes", with large eyes, a convex carapace and flattened chelae, and the "microphthalmes", with small eyes, cylindrical carapace and more robust chelae. In their 1929 monograph, Théodore Monod and Petit recognised four "varieties", betsileoensis and madagascariensis (the "macrophthalmes") and brevirostris and granulimanus (the "microphthalmes"). In 1964, Lipke Holthuis realised that due to the suppression of the name goudotii, the epithet caldwelli would have to be used, although Holthuis continued to treat the different taxa as subspecies. In 1974, Horton H. Hobbs, Jr. published a monograph which finally raised the various taxa observed to that point to the rank of species, and introduced two new species. Since then, the only change has been the addition of a new species, described in 2005, and commemorating Hobbs, Astacoides hobbsi.