Megalosaurus dunkeri
A dubious theropod
"Megalosaurus" dunkeri is a dubious theropod dinosaur species known only from a single tooth. Wilhelm Dames first named and described it during a lecture in December 1884, though a synopsis appeared in an 1884 yearbook published in 1885, leading most sources to cite 1884 as the year. Some references instead give 1887, when Ernst Koken redescribed and illustrated the type specimen—a lone tooth—in a publication. The species name honors paleontologist Wilhelm Dunker, who had discovered the tooth years earlier in the main coal seam of Obernkirchen on the Deister. Dunker added the holotype, catalog number UM 84, to the University of Marburg collection.
In 1888, Richard Lydekker assigned some fragmentary Early Cretaceous English specimens previously referred to *Megalosaurus* to "M." dunkeri, making it widely understood as a European Early Cretaceous theropod. One putative specimen from the Wealden later became the holotype of *Megalosaurus oweni* in 1889. In 1923, Friedrich von Huene created the name *Altispinax dunkeri* for a tooth specimen, though he later applied it to NHMUK R1828, three articulated dorsal vertebrae with very tall neural spines. The vertebrae are now considered the holotype of *Becklespinax altispinax*, not *Altispinax dunkeri*. The genus name combines Latin "altus" (high) with Neo-Latin "spinax." In 1939, Oskar Kuhn mistakenly listed "Megalosaurus dunkeri" as the type species of *Altispinax*, unaware that von Huene had erected *Altispinax dunkeri* through deliberate misidentification.
A 2016 study by Michael W. Maisch argued that *Altispinax dunkeri* is a valid taxon. Maisch claimed von Huene did not create *Altispinax* as a new genus for "M." dunkeri, but instead erected a new species by deliberate misidentification under Article 11.10 of the International Code of Zoological Nomenclature. According to Maisch, the original description of *A. dunkeri* was based not on the "M." dunkeri holotype tooth, but on three articulated vertebrae from the Wealden of East Sussex—the same specimen later made the type of *Becklespinax altispinax*. Maisch considered *Becklespinax* an objective junior synonym of *Altispinax*, and *Becklespinax altispinax* an objective junior synonym of *Altispinax dunkeri*.
The "M." dunkeri holotype tooth is a crown six centimeters long with a base length of twenty-two millimeters.
Quick Facts
- Genus
- Megalosaurus
- Species
- dunkeri
Facts from the source article.
Lore & Background
The species was originally named and described by Wilhelm Dames during a lecture in December 1884, with a synopsis published in an 1884 yearbook, though some sources cite 1887 as the publication year. The holotype tooth, discovered by Wilhelm Dunker in the main coal seam of Obernkirchen on the Deister, was added to the University of Marburg collection under inventory number UM 84. In 1888, Richard Lydekker assigned some Early Cretaceous English specimens to "M." dunkeri, but one such specimen from the Wealden later became the holotype of Megalosaurus oweni in 1889. Friedrich von Huene created the name Altispinax dunkeri in 1923 for a tooth specimen, later applying it to a series of three dorsal vertebrae with high neural spines; those vertebrae are now the holotype of Becklespinax altispinax. Oskar Kuhn mistakenly listed "Megalosaurus dunkeri" as the type species of Altispinax in 1939.
Reader's Guide
The significance of "Megalosaurus" dunkeri lies in its role as a taxonomic puzzle in dinosaur paleontology. Originally based on a single tooth from the Early Cretaceous of Germany, the species became a catch-all for various fragmentary theropod remains from Europe, leading to confusion and multiple reassignments. The 2016 study by Michael W. Maisch argued that Altispinax dunkeri was a valid taxon based on diagnostic vertebrae, not the original tooth, and considered Becklespinax an objective junior synonym. This illustrates the challenges of classifying dinosaurs from isolated teeth and the importance of type specimens in nomenclature. The tooth itself, moderately recurved with serrations only on the back edge, was initially distinguished from Megalosaurus bucklandii by lacking front-edge serrations and having a flatter cross-section, though Lydekker noted these traits could result from wear or compression. The species remains dubious, highlighting how early paleontological work often relied on incomplete material.
Did You Know?
- The holotype tooth of "Megalosaurus" dunkeri has a crown length of six centimetres and a base length of twenty-two millimetres.
- Wilhelm Dames named the species during a lecture on 16 December 1884, but the synopsis was published in an 1884 yearbook.
- Friedrich von Huene created the name Altispinax dunkeri in 1923 for three dorsal vertebrae with very high neural spines.
- The specific name honors paleontologist Wilhelm Dunker, who discovered the tooth many years earlier on the Deister.
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