Altispinax or backlespinax? And finally, Georgy Olshevsky's current list?

[Илья Садыков]

I am concerned by the fact that, according to Olshevsky's list, Becklespinax is not considered doubtful, and apparently Olshevsky himself also questioned the 2016 paper and unfortunately passed away not so long ago, and now his list is being viewed by another person.

[Mickey Mortimer]

If you mean his list is being ARCHIVED by another person, like the Internet Archive ( https://web.archive.org/web/20060707013851/http://members.aol.com/Dinogeorge/dinolist.html ) I think he probably would have wanted a record of it to be available for future scholars. As far as I know, nobody has taken over his old website and continued it.

As for Becklespinax, if someone thinks Maisch is wrong they can always argue that. Nobody is entitled to have taxa they name be viewed as valid just because they think they're valid. And Maisch's paper was detailed and precise, so it's not like he just trashed Becklespinax. If anything, I'd say Jenghizkhan never got a fair shake, being basically assumed to be an unjustified split based on ontogenetic differences. Yet Olshevsky claimed since the Gorgosaurus lancinator holotype (PIN 553-1) is a smaller specimen than the Tarbosaurus efremovi holotype (PIN 551-2), yet shows the cranial characters of PIN 551-1, it is a juvenile Jenghizkhan and the characters are not ontogenetic. And the supposedly diagnostic postcranial characters (well developed anterior dorsal parapophyses; tall anterior dorsal neural arches; well developed anterior dorsal neural arch laminae) have never been engaged with AFAIK. With a recent abstract advocating for multiple Tarbosaurus species, we might just see George vindicated.

Mickey Mortimer

[Gregory Paul]

It is the tyrannosaur taxonomic wild west out there now, what with the ETRH at the bottom of the paleo ocean and all having been sunk by the MTTH. "T." bataar holotype has always looked diff from the other big Nemegt skulls. Carr thinks those are all Tyrannosaurus and that may be right if they share a recent common ancestor. Phil C. has been suspecting that the tarbos are multiple species. Where is the abstract indicating such Mickey? 

GSPaul

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[Ethan Schoales]

What does MTTH stand for?

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[Gregory Paul]

Multiple tyrannosaur species hypothesis as applied to the TT-zone (Tyrannosaurus-Triceratops). Check out https://doi.org/10.11646/mesozoic.2.2.1 (fast approaching 10K looks:) if you have not already. The terms go back to Paul et al. (2022). 

GSPaul

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[Mickey Mortimer]

The 2025 Canadian Society of Vertebrate Paleontology abstract book. The abstract in question is-

"Who was the ruler of Maastrichtian Mongolia?
Taxonomic revision of Tarbosaurus provides insight
into tyrannosaurid diversity of central Asia 

Gorm S. Raun, Henry S. Sharpe, Mark J. Powers, and Philip J. Currie

Department of Biological Sciences, University of Alberta, P217 Biological Sciences Building, Edmonton, AB T6G 2E9;
gorm...@ualberta.ca; hssh...@ualberta.ca; pow...@ualberta.ca; pjcu...@ualberta.ca

Tarbosaurus Maleev, 1955b is one of the largest tyrannosaurids known, commonly occurring in the Maastrichtian
of Mongolia. The genus and species within have had a complex history dating back to when the original
species, now known as Tarbosaurus bataar, was named. Four different species in three different genera have
previously been named, although today only one is considered valid. Considered by many as the sister taxon to
Tyrannosaurus rex, the species is known from several adult individuals with relatively complete skulls. One individual,
ZPAL MgD I/4, has been described in great detail, and shows significant differences in cranial structure
from the larger North American taxon. The Nemegt Formation and its large sample size therefore provide ample
opportunity to study the variation in dimensions and discrete characters. A new species of tyrannosaurid is being
proposed based on several complete crania, and has several consistent morphological differences, including an
autapomorphy separating the taxon from Tarbosaurus bataar. Morphometric analysis of the diagnostic maxilla reveals
a clear separation in morphology between the two Tarbosaurus species. Namely, in the new species, the most
posterior point of the dorsal subcutaneous surface is far anterior to the lacrimal contact, and the maxilla is relatively
deeper in the largest specimens. While the stratigraphy of the Nemegt Formation is contentious, the new
taxon is found almost exclusively in the western Nemegt localities, whereas Tarbosaurus bataar is found almost
exclusively in the eastern localities. The Nemegt Formation is already known for its diversity of small theropods
at different localities within a relatively small area. This suggests temporal or palaeoenvironmental differences that
we presently do not understand.
The relationships of the specimens were analyzed using an in-group tyrannosaurid character matrix based on
discrete characters, rather than allometric characters. Ontogenetically invariant, discrete characters do not force
potentially unrelated large taxa to clade together because of size. The resulting tree topologies suggest a more
complex evolutionary history of Tyrannosauridae than previous analyses, including the existence of a potential
monophyletic central Asian clade. The discovery of another giant tyrannosaurid underlines the value of constructing
discrete characters for alpha taxonomic work and increases our knowledge of the evolution and distribution
of Tyrannosauridae."

Mickey Mortimer

[Gregory Paul]

As the Arte Johnson character used to say on Rowan & Martin's Laugh-In, interesting, very interesting. Indeed:)

For a same scale comparison of a bunch of these skulls one can check out Fig. 2J-Q at https://doi.org/10.11646/mesozoic.2.2.1

Danka, 

GSPaul

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.

[Илья Садыков]

Hmm, thanks. Actually, until recently, I hadn't looked at Olshevsky's list. It all started because of a discussion with my acquaintance about these three vertebrae and the priority of names.

воскресенье, 30 ноября 2025 г. в 04:48:12 UTC+5, Mickey Mortimer: