Johannes Thiele
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Johannes Thiele (1860 - 1935) was a German zoologist specialized in malacology. His Handbuch der systematischen Weichtierkunde (English edition published by the Smithsonian under the title Handbook of Systematic Malacology) is a standard work.
The classification of Gastropoda has been in use up to the past decade. It is based primarily on the authoritative work of J. Thiele (1929 - 1931), who modified an earlier concept of Henri Milne-Edwards (1848) with three subclasses: Prosobranchia, Opisthobranchia and Pulmonata. His classification was based on overall similarity between the species; This classification has now been replaced by the classification of Ponder & Lindberg, 1997, based on phylogenetic arguments. From 1904 until his retirement in 1925 he was the curator of the malacological collection at the Museum of Natural History in Berlin.
Johannes Thiele was also ahead of his time in organic chemistry. In 1865 Kekulé had proposed a ring structure with alternating bonds for the formula for benzene. For convenience nowadays, we represent the benzene ring by a regular hexagon containing a circle. The straight lines represent the σ bonds between the carbon atoms, and the circle stands for the cloud of the six delocalized π electrons. But already in 1899 Thiele proposed a resonance structure for benzene ring, by using a broken circle to represent the partial bonds. That was long before the exact nature of the bonds was explained !
Reference
- Thiele, J., 1929-1935. Handbuch der Systematischen Weichtierkunde. 2 vols. 1154 p., 584 figs
- Bieler, R. & P. M. Mikkelsen (eds.), 1992. Handbook of Systematic Malacology, Part 1 (Loricata [Polyplacophora]; Gastropoda: Prosobranchia). Smithsonian Institution and National Science Foundation, xviii + 625 pp., 470+1 text-fig. (Annotated English-language edition of: Thiele, J., Handbuch der systematischen Weichtierkunde, Teil 1). Also published, in 1993, by Gustav Fischer Verlag, Stuttgart/Jena/New York.