Later researchers considered "Altispinax" a "nomen dubium" because the single tooth was undiagnostic. No relationship could be proven between the tooth and the vertebrae. The vertebrae were therefore given a new name in 1988 by Gregory Paul. Paul considered them to represent a possible new species of "Acrocanthosaurus", which he named "Acrocanthosaurus? altispinax". The specific name was deliberately made identical to the old generic name, to emphasize that both referred to the vertebrae. As indicated by the question mark, Paul himself was uncertain about this assignment. For this reason, in 1991 a new genus, "Becklespinax", was named for the vertebrae by George Olshevsky, in honour of the original discoverer, Beckles. The new combination name of the type species "Acrocanthosaurus? altispinax" thus became "Becklespinax altispinax". The species names "Altispinax altispinax" and "Altispinax lydekkerhueneorum" are its junior objective synonyms. In 2016, a re-examination of this convoluted history of classification was published by Michael Maisch. Maisch concluded that von Huene, when he named "Altispinax dunkeri", deliberately based the species on the vertebrae and not on the "Megalosaurus dunkeri" tooth. Because both species were based on different type specimens, later researchers were wrong to consider them the same species. Rather, according to Maisch's interpretation of the rules of the ICZN, "Altispinax dunkeri" (based on the tall-spined vertebrae) and "Megalosaurus dunkeri" (based on the tooth from Germany) are two distinct species that happen to share the same species name. Because the later names created by Paul and Olshevsky were based on the same vertebrae used by von Huene to name "Altispinax dunkeri", all of those later names must be considered junior objective synonyms (different names for exactly the same fossil), and "Altispinax dunkeri", having been named first, has priority as the correct name for this species.