arvernensis
(pictured), were classified to the genus Mastodon'' "
Mastodon" was riddled with major taxonomic problems since proboscidean species whose dentitions matched neither
elephantids nor
deinotheres were regularly classified to the genus, effectively making it a
wastebasket taxon. In the early taxonomic history of the mammutid genus, species now determined as belonging to other proboscidean genera were classified to
Mastodon on the basis of similar dentitions to that of "
Mastodon giganteum" (=
Mammut americanum). Various fossil proboscidean species from Europe and Asia were classified into
Mastodon in the 19th century before eventually being reclassified into distinct genera. The same year, French naturalists
Jean-Baptiste Croizet and
A. Jobert erected another species
Mastodon arvernensis, naming it after the French region
Auvergne and giving it the common name "Auvergne mastodon." In 1832, German naturalist
Johann Jakob Kaup established the species
Tetracaulodon longirostre, which later was reclassified as
Mastodon longirostris. In 1834, American naturalist
Isaac Hays established that the proboscidean teeth from
Piedmont, Italy, attributed by Italian naturalist
Stefano Borson to
Mastodon giganteum, belonged to a different species based on dental morphology. He determined that it may have belonged to a different species, giving from Borson the name
Mastodon borsoni. The English naturalist
Proby Cautley erected an additional species
M. Sivalensis in 1836 based on the proportions of a tooth from the
Siwalik Hills. Several genera were erected for European "
Mastodon" species, but most 19th century naturalists did not recognize them as distinct. In 1836, German zoologist
Hermann Burmeister established the genus
Gomphotherium, diagnosing it as an extinct proboscidean with tusks in both jaws, but he did not specify any species that belonged to the genus. Apparently unaware of the prior genus name, Falconer and Cautley established the subgenus name
Trilophodon in 1846 for some species of
Mastodon. In the same journal in 1847, the species previously referred to
Mastodon by Clift were transferred to
Elephas by Falconer and Cautley, who also erected the subgenus name
Stegodon. Falconer and Cautley also erected another species
M. perimensis by 1847. They also established that the teeth assigned to a "
M. minutus" were really just teeth of a young
M. angustidens, effectively making the former a synonym. Falconer and Cautley also wrote that remains attributed by Cuvier to "
M. Humboldtii" can instead be assigned to the other species
M. Andium, turning the former species into a synonym. which was synonymized by French paleontologist
Édouard Lartet with
M. arvernensis in 1859. In 1857, Falconer erected the subgenus
Tetralophodon for the species
M. arvernensis,
M. longirostris, and
M. sivalensis. In 1844, British naturalist
Richard Owen established an Australian species
M. australis based on an inland molar that seemed to resemble those of typical "
Mastodon" species rather than other large marsupials like
Diprotodon or
Nototherium. Along with "
Notelephas australis" in 1882, it is possible that proboscidean remains may have been transported by ocean into the Australian mainland, but this explanation fails to explain why the "
M. australis" molar, now lost, was found inland. As a result, "
M. australis" and "
N. australis" remain unresolved enigmas. In 1856, French paleontologists
Jean Albert Gaudry and Lartet erected an Asian species
M. pentelicus. German paleontologist
Johann Andreas Wagner established another proboscidean species
M. atticus in 1857. Lartet later erected another European proboscidean species
M. pyrenaicus in 1859. Falconer established the name
Mastodon pandionis in 1868 based on fossil molars from India. In 1877, Michael Vacek pointed out that certain proboscideans had "zygolophodont" dentitions as opposed to more "bunolophodont" dentitions. Establishing differences in dental morphologies for European species, he classified some species like
M. tapiroides into the
Zygolophodon subgenus and other species like
M. angustidens into the
Bunolophodon subgenus. Many Eurasian proboscidean species remained classified to the genus
Mastodon for the rest of the 19th century while the other genus names like
Trilophodon,
Tetralophodon, and
Anancus were considered synonyms of
Mastodon by
Richard Lydekker in 1886. He also established another species
M. cautleyi the same year. Lydekker also recognized that
M. turiciensis took taxonomic priority over
M. tapiroides. French paleontologist
René Fourtau erected two proboscidean species from
Wadi Moghara, Egypt named
M. spenceri and
M. angustidens var. libyca in 1918–1920. Austrian paleontologist
Günther Schlesinger erected the subspecies
M. augustidens forma subtapiroidea in 1917, and German paleontologist
Hans Klähn established the species
M. steinheimensis in 1922. == Early American taxonomic history ==