Do theropods described in Science and Nature get fully described eventually? Fifteen years later...

So here's a fun one to finish up the year (got delayed due to computer issues; yes, more Titanosaurus is coming, but Curtice's excellent blog post on the unreliability of illustrations makes it at least somewhat less relevant). Over fifteen years ago, I wrote "Do theropods described in Science and Nature get fully described later?" As I summarized in that post- "Basically, we have a system that rewards publishing in Nature and Science (the so-called tabloids) despite the fact papers in those journals are universally thought to be too short due to space restrictions.  The usual response is that Nature/Science papers are just meant to be preliminary announcements that will be followed by more detailed coverage later.  But how often does this actually happen?" So that was 2010. Where do we stand in 2025? Surely these taxa have been described in the past FIFTEEN years?!

First of all, I'll say that for better or worse the HUGE expansion of supplementary information has meant that the basic problem no longer needs to exist. There are plenty of taxa described in the tabloids recently that get tens of pages worth of detailed description and figures in the supp info (e.g. Halszkaraptor).  I miss the days when you didn't have to also comb through what is basically an abridged description in the paper proper for details missed in the supp info, or copy the supp info description to another file to read alongside looking at the figures, or have to wait to read the supp info to even know what the taxon list was for Jenkins et al.'s (2025) amniote phylogenetic analysis (no, the other Jenkins). And the tabloids' supp info is free unlike a certain journal named after chalk, so they deserve credit for that.

But for this update, we're sticking with taxa named by September 2010. As an additional rule, I'm only counting redescriptions of the type material, not new specimens being described later, though I will mention those. Also, this only concerns anatomy, so if the material was later used in an analysis about function, growth, taphonomy, etc. that doesn't count toward getting the basic description out there.

Eoraptor
Sereno, Forster, Rogers and Monetta, 1993. Primitive dinosaur skeleton from Argentina and the early evolution of Dinosauria. Nature. 361, 64-66.
Redescription in progress for over a decade for publication as a JVP monograph. Yeah, it's probably a sauropodomorph now, but we got the redescription three years later-
Sereno, Martinez and Alcober, 2013. Osteology of Eoraptor lunensis (Dinosauria, Sauropodomorpha). Journal of Vertebrate Paleontology. 32(Supplement to 6), 83-179.

Limusaurus
Xu, Clark, Mo, Choiniere, Forster, Erickson, Hone, Sullivan, Eberth, Nesbitt, Zhao, Hernandez, Jia, Han and Guo, 2009. A Jurassic ceratosaur from China helps clarify avian digital homologies. Nature. 459, 940-944.
Not redescribed. Redescribed in Stiegler's (2019) unpublished thesis, which is a step closer.

Masiakasaurus
Sampson, Carrano and Forster, 2001. A bizarre predatory dinosaur from the Late Cretaceous of Madagascar. Nature. 409, 504-506.
Carrano, Sampson and Forster, 2002. The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology. 22(3), 510-534.
Also new material described by Carrano et al. (2011).

Baryonyx
Charig and Milner, 1986. Baryonyx, a remarkable new theropod dinosaur. Nature. 324, 359-361.
Charig and Milner, 1997. Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bulletin of the Natural History Museum of London (Geology). 53, 11-70.

Giganotosaurus
Coria and Salgado, 1995. A new giant carnivorous dinosaur from the Cretaceous of Patagonia. Nature. 377, 224-226.
Not redescribed yet except for the braincase in 2002 (Coria and Currie). This is sadly still true, although Hendrickx et al. (2014) figure the quadrate in all views (mislabeled Shaochilong in the caption for Figure 11), Novas et al. (2013) figure the maxilla and dentary, Eddy and Clarke (2011) figure the lacrimal and ectopterygoid.

Siamotyrannus
Buffetaut, Suteethorn and Tong, 1996. The earliest known tyrannosaur from the Lower Cretaceous of Thailand. Nature. 381(6584), 689-691.
Not redescribed. Redescribed in Samathi's (2019) unpublished thesis, which again is a step closer.

Dilong
Xu, Norell, Kuang, Wang, Zhao and Jia, 2004. Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids. Nature. 431, 680-684.
Not redescribed, though White (2009) briefly described the metatarsus and Kundrat et al. (2020) described the endocast.

Guanlong
Xu, Clark, Forster, Norell, Erickson, Eberth, Jia and Zhao, 2006. A basal tyrannosauroid dinosaur from the Late Jurassic of China. Nature. 439, 715-718.
Not redescribed. Redescribed in Choiniere's (2010) unpublished thesis. There's some useful information in Ke et al. (2024) on its tooth replacement and Yu et al. (2015) on its manual motion.

Juravenator
Gohlich and Chiappe, 2006. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago. Nature. 440, 329-332.
Gohlich, Tischlinger and Chiappe, 2006. Juravenator starki (Reptilia, Theropoda) ein neuer Raubdinosaurier aus dem Oberjura der Sudlichen Frankenalb (Suddeutschland): Skelettanatomie und Weichteilbefunde. Archaeopteryx. 24, 1-26.
We actually got an even better re-redescription of this as-
Chiappe and Gohlich, 2011. Anatomy of Juravenator starki(Theropoda: Coelurosauria) from the Late Jurassic of Germany. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 258(3), 257-296.

Scipionyx
Dal Sasso and Signore, 1998. Exceptional soft tissue preservation in a theropod dinosaur from Italy. Nature. 392, 383-387.
Described in depth in Signore's thesis, which isn't published.  Dal Sasso and Maganuco are writing a monograph which Auditore said would be out in 2009 or early 2010, but it seems to be delayed. Hey, we got it the next year-
Dal Sasso and Maganuco, 2011. Scipionyx samniticus (Theropoda: Compsognathidae) from the Lower Cretaceous of Italy: Osteology, ontogenetic assessment, phylogeny, soft tissue anatomy, taphonomy, and palaeobiology. Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano. 281 pp.

Pelecanimimus
Perez-Moreno, Sanz, Buscalioni, Moratalla, Ortega and Rasskin-Gutman, 1994. A unique multitoothed ornithomimosaur dinosaur from the Lower Cretaceous of Spain. Nature. 370, 363-367.
Redescribed in Perez-Moreno's (2004) unpublished thesis (which everyone refuses to distribute...). BUT, we're partway to resolution with the postcrania being redescribed-
Cuesta, Vidal, Ortega, Shibata and Sanz, 2022 (online 2021). Pelecanimimus (Theropoda: Ornithomimosauria) postcranial anatomy and the evolution of the specialized manus in Ornithomimosaurs and sternum in maniraptoriforms. Zoological Journal of the Linnean Society. 194(2), 553-591.

Shuvuuia
Chiappe, Norell and Clark, 1998. The skull of a relative of the stem-group bird Mononykus. Nature. 392, 275-278.
Not redescribed. The skull was redescribed in Dufeau's (2003) unpublished thesis. There are useful photos in Chiappe et al. (2002) and Sereno (2001). I took pictures of all the postcranial specimens at the AMNH, so it's not affecting me THAT much, but is still bad for the community. Suzuki et al. (2002) described IGM 100/120, but this may be closer to Parvicursor. 

Mononykus
Perle, Norell, Chiappe and Clark, 1993. Flightless bird from the Cretaceous of Mongolia. Nature. 362, 623-626.
Perle, Chiappe, Barsbold, Clark and Norell, 1994. Skeletal morphology of Mononykus olecranus (Theropoda: Avialae) from the Late Cretaceous of Mongolia. American Museum Novitates. 3105, 1-29.

Falcarius
Kirkland, Zanno, Sampson, Clark and DeBlieux, 2005. A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah. Nature. 435, 84-87.
Zanno, 2006. The pectoral girdle and forelimb of the primitive therizinosauroid Falcarius utahensis (Theropoda, Maniraptora): Analyzing evolutionary trends within Therizinosauroidea. Journal of Vertebrate Paleontology. 26(3), 636-650.
Zanno, 2010. Osteology of Falcarius utahensis: Characterizing the anatomy of basal therizinosaurs. Zoological Journal of the Linnaean Society. 158, 196-230.
Smith, Zanno, Sanders, Deblieux and Kirkland, 2011. New information on the braincase of the North American therizinosaurian (Theropoda, Maniraptora) Falcarius utahensis. Journal of Vertebrate Paleontology. 31(2), 387-404.
Lautenschlager, Rayfield, Perle, Zanno and Witmer, 2012. The endocranial anatomy of Therizinosauria and its implications for sensory and cognitive function. PLoS ONE. 7(12), e52289.
We've been mostly spoiled with this taxon, also getting a skull description with new materials (Freimuth and Zanno, 2025 online) among others. Could use better work on the pedal phalanges though...

Beipiaosaurus
Xu, Tang and Wang 1999. A therizinosauroid dinosaur with integumentary structures in China. Nature. 399, 350-354.
Not redescribed. Here's exactly what I want to see from all of these type specimens-
Xu, Cheng, Wang and Chang, 2003. Pygostyle-like structure from Beipiaosaurus (Theropoda, Therizinosauroidea) from the Lower Cretaceous Yixian Formation of Liaoning, China. Acta Geologica Sinica. 77(3), 294-298.
Liao and Xu, 2019. Cranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria). Vertebrata PalAsiatica. 57(2), 117-132.
Liao, Zanno, Wang and Xu, 2021. Postcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria). PLoS ONE. 16(9), e0257913.
There's also a more articulated skeleton with complete skull figured by Xu et al. (2009) that has yet to receive a detailed description.

Incisivosaurus
Xu, Cheng, Wang and Chang, 2002. An unusual oviraptorosaurian dinosaur from China. Nature. 419, 291-293.
Balanoff, Xu, Kobayashi, Matsufune and Norell, 2009. Cranial osteology of the theropod dinosaur Incisivosaurus gauthieri (Theropoda: Oviraptorosauria). American Museum Novitates. 3651, 35 pp.
Xu et al. (2010) also briefly described two juvenile skeletons in Nature as Similicaudipteryx, but these have been recently suggested to be Incisivosaurus (Xu, 2020; and have not been redescribed in detail yet, ironically).

Caudipteryx
Ji, Currie, Norell and Ji, 1998. Two feathered dinosaurs from northeastern China. Nature. 393, 753-761.
The type specimens haven't been redescribed, though Zhou et al. (2000) and Zhou and Wang (2000) did describe others in more depth.

Gigantoraptor
Xu, Tan, Wang, Zhao and Tan, 2007. A gigantic bird-like dinosaur from the Late Cretaceous of China. Nature. 844-847.
Not redescribed. Mandible redescribed by Ma et al. (2017).

Mei
Xu and Norell, 2004. A new troodontid dinosaur from China with avian-like sleeping posture. Nature. 431, 838-841.
Not redescribed. A second specimen was described by Gao et al. (2012)

Sinovenator
Xu, Norell, Wang, Makovicky and Wu, 2002. A basal troodontid from the Early Cretaceous of China. Nature. 415, 780-784.
Not redescribed. Redescribed in Xu's (2002) unpublished thesis, and White (2009) briefly described the metatarsus. We've also had another partial skull described by Yin et al. (2018), and an endocast described by Yu et al. (2024).

Archaeornithoides
Elzanowski and Wellnhofer, 1992. A new link between theropods and birds from the Cretaceous of Mongolia. Nature. 359, 821-823.
Elzanowski and Wellnhofer, 1993. Skull of Archaeornithoides from the Upper Cretaceous of Mongolia. American Journal of Science. 293-A, 235-252.

Buitreraptor
Makovicky, Apesteguía and Agnolín, 2005. The earliest dromaeosaurid theropod from South America. Nature. 437, 1007-1011.
Not redescribed. Gianechini et al. have really knocked this one out of the park-
Gianechini, Makovicky and Apesteguia, 2011. The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids. Acta Palaeontologica Polonica. 56(2), 279-290.
Gianechini, Makovicky and Apesteguıa, 2017. The cranial osteology of Buitreraptor gonzalezorum Makovicky, Apesteguıa, and Agnolın, 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia, Argentina. Journal of Vertebrate Paleontology. e1255639.
Gianechini, Makovicky, Apesteguia and Cerda, 2018. Postcranial skeletal anatomy of the holotype and referred specimens of Buitreraptor gonzalezorum Makovicky, Apesteguia and Agnolin 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia. PeerJ. 6:e4558.
Motta, Brisson Egli and Novas, 2018 (online, 2017). Tail anatomy of Buitreraptor gonzalezorum (Theropoda, Unenlagiidae) and comparisons with other basal paravians. Cretaceous Research. 83, 168-181.
Plus we have Novas et al. (2018; online 2017) on a referred specimen.

Unenlagia
Novas and Puerta, 1997. New evidence concerning avian origins from the Late Cretaceous of Patagonia. Nature. 387: 390-392.
Not redescribed except the ilium by Novas (2004).
Novas, Agnolin, Motta and Egli, 2021. Osteology of Unenlagia comahuensis (Theropoda, Paraves, Unenlagiidae) from the Late Cretaceous of Patagonia. The Anatomical Record. 304(12), 2741-2788.
Gianechini and Zurriaguz, 2021. Vertebral pneumaticity of the paravian theropod Unenlagia comahuensis, from the Upper Cretaceous of Patagonia, Argentina. Cretaceous Research. 127, 104925.

Sinornithosaurus
Xu, Wang and Wu, 1999. A dromaeosaurid dinosaur with filamentous integument from the Yixian Formation of China. Nature. 401, 262-266.
Redescribed in Xu's (2002) unpublished thesis. Not redescribed except for The skull (Xu and Wu, 2001), pes (Xu and Wang, 2000), and feathers (Xu et al., 2001) have been published. Of course S. haoiana and NGMC 91 may be synonymous, but these have not been described in detail, which if it is eventually done may enable us to judge this synonymy better.

Microraptor
Xu, Zhou and Wang, 2000. The smallest known non-avian theropod dinosaur. Nature, 408, 705-708.
The holotype has not been redescribed, though Redescribed in Xu's (2002) unpublished thesis. Two other specimens were monographed (Hwang et al., 2002) in time for my prior post, and now we also have detailed descriptions of other specimens (Pei et al., 2014; Xu and Li, 2016; Grosmougin et al., 2025; Chotard et al., 2025; etc.).

Microraptor gui
Xu, Zhou, Wang, Kuang, Zhang and Du, 2003. Four-winged dinosaurs from China. Nature. 421, 335-340.
Not redescribed, though White (2009) briefly described the metatarsus. But in 2025 I'd argue it's not that important, as it's generally seen as a junior synonym of M. zhaoianus and plenty of specimens of that have been well described. I guess it is kinda insulting to be sunk before being described in detail.

Neuquenraptor
Novas and Pol, 2005. New evidence on deinonychosaurian dinosaurs from the Late Cretaceous of Patagonia. Nature. 433, 858-861.
Not redescribed.
Brissón Egli, Rolando Aranciaga, Agnolín and Novas, 2017. Osteology of the unenlagiid theropod Neuquenraptor argentinus from the Late Cretaceous of Patagonia. Acta Palaeontologica Polonica. 62(3), 549-562.

Epidexipteryx
Zhang, Zhou, Xu, Wang and Sullivan, 2008. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Nature. 455, 1105-1108.
Not redescribed.

Jeholornis
Zhou and Zhang, 2002. A long-tailed, seed-eating bird from the Early Cretaceous of China. Nature. 418, 405-409.
The holotype is not redescribed. We have the description of J. palmapenis by O'Connor et al. (2012; online 2011), which I think is synonymous with the type species. Plus detailed descriptions of other specimens' skull (Hu et al., 2022) and sternal ribs (Zheng et al., 2020). 

Confuciusornis dui
Hou, Martin, Zhou, Feduccia and Zhang, 1999. A diapsid skull in a new species of the primitive bird Confuciusornis. Nature. 399, 679-682.
Not redescribed. And lost according to Marugán-Lobón et al. (2011). Is that worse than Microraptor gui? Getting lost before you can be described in detail? Maybe we shouldn't give any more theropods _ui as a species name.

Enantiornis
Walker, 1981. New subclass of birds from the Cretaceous of South America. Nature. 292, 51-53.
Not redescribed.
Walker and Dyke, 2009. Euenantiornithine birds from the Late Cretaceous of El Brete (Argentina). Irish Journal of Earth Sciences. 27, 15-62.

Vorona
Forster, Chiappe, Sampson, Krause, 1996. The first Cretaceous bird from Madagascar. Nature. 382, 532-534.
Forster, Chiappe, Krause and Sampson, 2002. Vorona berivotrensis, a primitive bird from the Late Cretaceous of Madagascar. 268-280. In Chiappe and Witmer (eds.). Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press, Berkeley, Los Angeles, London.

Eoalulavis
Sanz, Chiappe, Perez-Moreno, Buscalioni, Moratalla, Ortega and Poyato-Ariza, 1996. An Early Cretaceous bird from Spain and its implications for the evolution of avian flight. Nature. 382, 442-445.
Sanz, Pérez-Moreno, Chiappe and Buscalioni, 2002. The Birds from the Lower Cretaceous of Las Hoyas (Privince of Cuenca, Spain). pp 209-229. In Chiappe and Witmer (eds.). Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press, Berkeley, Los Angeles, London.

Nanantius
Molnar, 1986. An enantiornithine bird from the Lower Cretaceous of Queensland, Australia. Nature 322 736-738.
Not redescribed. And apparently lost (O'Connor, 2009), so there's a second such taxon.

Apsaravis
Norell and Clarke, 2001. Fossil that fills a critical gap in avian evolution. Nature. 409, 181-184.
Clarke and Norell, 2002. The morphology and phylogenetic position of Apsaravis ukhaana from the Late Cretaceous of Mongolia. American Museum Novitates. 3387, 1-46.



So that's Nature, but what about Science?

Tawa
Nesbitt, Smith, Irmis, Turner, Downs and Norell, 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs. Science. 326, 1530-1533.
Not redescribed fully, though Bradley et al. (2020; as 2019) did describe the sternals and Burch's (2013) unpublished thesis described the pectoral girdle and forelimb. There have been a lot of papers on isolated limb elements, and Burch (2014) on the forelimb musculature, but no osteology.

Cryolophosaurus
Hammer and Hickerson, 1994. A crested theropod dinosaur from Antarctica. Science. 264, 828-830.
Smith, Makovicky, Hammer and Currie, 2007. Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zoological Journal of the Linnean Society. 151, 377-421.

Deltadromeus
Sereno, Dutheil, Iarochene, Larsson, Lyon, Magwene, Sidor, Varricchio and Wilson, 1996. Predatory dinosaurs from the Sahara and Late Cretaceous faunal differentiation. Science. 272(5264), 986-991.
Not redescribed, though apparently being worked on by Ibrahim. Ibrahim et al. (2020) figured parts of the pes.

Piatnitzkysaurus
Bonaparte, 1979. Dinosaurs: A Jurassic assembalge from Patagonia. Science. 205, 1377-1379
Bonaparte, 1986. Les Dinosaures (Carnosaures, Allosauridés, Sauropodes, Cétiosauridés) du Jurassique moyen de Cerro Cóndor (Chubut, Argentine). Annales de Paléontologie. Paris, France. 72, 247-289.
We also had...
Rauhut, 2004. Braincase structure of the Middle Jurassic theropod dinosaur Piatnitzkysaurus. Canadian Journal of Earth Science. 41(9), 1109-1122.
... and more recently...
Pradelli, Pol and Ezcurra, 2025. The appendicular osteology of the Early Jurassic theropod Piatnitzkysaurus floresi and its implications on the morphological disparity of non-coelurosaurian tetanurans. Zoological Journal of the Linnean Society. 203(1), zlae176.

Afrovenator
Sereno, Wilson, Larsson, Dutheil and Sues, 1994. Early Cretaceous dinosaurs from the Sahara. Science. 266, 267-271.
Not redescribed. The maxilla was figured by Carrano et al. (2012) and the teeth detailed in Hendrickx et al. (2015).

Suchomimus
Sereno, Beck, Dutheil, Gado, Larsson, Lyon, Marcot, Rauhut, Sadleir, Sidor, Varricchio, Wilson and Wilson, 1998. A long-snouted predatory dinosaur from Africa and the evolution of the spinosaurids. Science. 282(5392), 1298-1302.
Not redescribed. A furcula was described by Lipkin et al. (2007) and we'll get occasional line drawings in works like Samathi et al. (2021) and Isasmendi et al. (2024), but that's it. The referred skull roof is Eocarcharia (Kellemann et al., 2025).

Raptorex
Sereno, Tan, Brusatte, Kriegstein, Zhao and Cloward, 2009. Tyrannosaurid skeletal design first evolved at small body size. Science. 326(5951), 418-422.
Not redescribed, though the associated fish vertebra was re-evaluated (Newbrey et al., 2013; Kim et al., 2022) to be a Nemegt Formation osteoglossomorph, so it's not the basal Jehol taxon Sereno et al. described it as in any case.

Haplocheirus
Choiniere, Xu, Clark, Forster, Guo and Han, 2010. A basal alvarezsauroid theropod from the Early Late Jurassic of Xinjiang, China. Science. 327, 571-574.
Not redescribed. Redescribed in Choiniere's (2010) unpublished thesis. Skull redescribed in-
Choiniere, Clark, Norell and Xu, 2014. Cranial osteology of Haplocheirus sollers Choiniere et al., 2010 (Theropoda: Alvarezsauroidea). American Museum Novitates. 3816, 44 pp.

Mahakala
Turner, Pol, Clarke, Ericson and Norell, 2007. A basal dromaeosaurid and size evolution preceding avian flight. Science. 317, 1378-1381.
Not redescribed. Turner, Pol and Norell, 2011. Anatomy of Mahakala omnogovae (Theropoda: Dromaeosauridae), Tögrögiin Shiree, Mongolia. American Museum Novitates. 3722, 66 pp.

Rahonavis
Forster, Sampson, Chiappe and Krause, 1998. The theropod ancestry of birds: New evidence from the Late Cretaceous of Madagascar. Science. 279, 1915-1919.
Not redescribed. Forster, O'Connor, Chiappe and Turner, 2020. The osteology of the Late Cretaceous paravian Rahonavis ostromi from Madagascar. Palaeontologia Electronica. 23(2):a31.

Protopteryx
Zhang and Zhou, 2000. A primitive enantiornithine bird and the origin of feathers. Science. 290, 1955-1959.
Not redescribed. New specimens have been described in detail though (Chiappe et al., 2020, online 2019; O'Connor et al., 2020).

Sinornis
Sereno and Rao, 1992. Early evolution of avian flight and perching: New evidence from Lower Cretaceous of China. Science. 255, 845-848.
Sereno, Rao and Li, 2002. Sinornis santensis (Aves: Enantiornithes) from the Early Cretaceous of Northeastern China. pp 184-208. In Chiappe and Witmer, (eds.). Mesozoic Birds – Above the Heads of Dinosaurs. University of California Press, Berkeley, Los Angeles, London.
Honestly, it's a pretty bad redescription, with only the manus, pelvis and pes illustrated, but I'll count it as I did previously.

The 2010 post ended with "So, of all 33 theropods described in Nature, 25 (76%) have yet to be fully described in a published work.  Of all 11 theropods described in Science, 8 (73%) have yet to be fully described.  So in total, 75% haven't been redescribed."

Taken literally, of the 35 theropods described in Nature by 2010, 18 (51%) have yet to have their type specimens fully described in published literature. Of all 12 theropods described in Science by 2010, 7 (58%) have yet to be fully described. So in total, 53% haven't been redescribed.

It's an improvement of 22% over 15 years, which is better than nothing. But there's a more encouraging way to look at this. Due to technological advancements, theses are as easy to circulate as peer reviewed papers anymore, and when's the last time you saw the contents of a thesis actually change due to peer review? Offhand I'd say maybe 25 years ago.  So what's our ratio of taxa whose types haven't even been redescribed in a thesis? Only 18 (I'm counting Pelecanimimus) out of 47, so 38%. And a third of those have partial redescriptions out.

So going into 2026, what do we need? In an admittedly biased order of what I would like most first, I would say we need osteologies of the following that don't have an obvious group/person working on them- Dilong, Gigantoraptor, Jeholornis, Epidexipteryx, Tawa, Afrovenator, Mei, Suchomimus and Giganotosaurus. Half of those are at the IVPP, just sayin'.

If anyone knows that taxa on this post are being worked on my somebody I didn't mention, please chime in! 

Equal Weights vs. Implied Weights in the Lori analysis

While I finish the Ibirania vs. Titanosaurus post, the latest Nanotyrannus paper got me thinking about my resistance to unequal weighting. I learned phylogenetic analysis in the 90s when things were simpler, but over the past several years many papers have used implied weights (IW) for their preferred tress, often relegating equal weights (EW) to the supplementary info. They usually cite Goloboff, so I read his most recent paper on the topic (Goloboff et al., 2018). What the authors did was basically take 158 real morphological datasets ("with 50–149 taxa, and 22–1844 characters; average number of taxa is 80.7, average number of characters is 214.3") and used a Most Parsimonious Tree from each as the 'real' phylogeny, then used those datasets to make 316,000 reduced datasets "with the number of taxa randomly chosen between 40 and 80, number of characters one and half times the number of taxa." These reduced datasets simulate our analyses in the real world that cover only a fraction of real characters and taxa, sort of like how Bootstrap analyses work. Then they checked how closely these reduced datasets matched the 'real' tree using different weighting methods (plus Bayesian and Maximum Likelihood).

What they found was- "The tree inferred by implied weighting is (for almost every combination of taxa, characters and exponential function) more similar to the model tree than the tree inferred using equal weights (Fig. 2e). This difference is overwhelmingly in favour of implied weighting. The number of correct groups retrieved by implied weighting is, for all numbers of taxa, characters, and k, higher than for equal weights (Fig. 2f). The only aspect in which implied weighting performed worse than equal weights is in finding a larger proportion of incorrect groups." The latter sentence seems contradictory, but I take it to mean there were more polytomies in the reduced EW trees, so the IW trees' extra resolved nodes were often wrong. Which if I'm interpreting that right, is a tough blow for those authors who say "our IW results were more resolved, so we're going with those."

In any case, I was curious how the current Lori matrix (700 characters still, but up to 623 taxa with Dilophosaurus as the outgroup) would come out different if I used implied weights k=12 as Goloboff suggests. Both have a similar basic structure in Maniraptoromorpha-

|==coelurid/compsognathid grade
`--+--Ornithomimosauria
   `--+--Therizinosauria
      `--+--Alvarezsauroidea
         `--+--Oviraptorosauria
            `--+--Deinonychosauria
               `--+==basal Avialae
                  `--+--Enantiornithes
                     `--Euornithes

But the differences are interesting (see below for what * means). I'll list some notable ones in three categories-

1. Ways in which EW more closely matches the consensus.
*- Huinculsaurus is an elaphrosaurine, not a noasaurine.
*- Masiakasaurus and Velocisaurus are noasaurines, not basal noasaurids.
*- Koleken is an abelisaurid, not a noasaurid.
*- Piatnitzkysaurids are basal to eustreptospondyline/afrovenatorine-grade megalosauroids, even if they are in the latter clade.
*- Shidaisaurus is a metriacanthosaurid, not a megalosauroid.
*- Xuanhanosaurus and Kaijiangosaurus are metriacanthosaurids, not carcharodontosaurids. Of course these taxa have uncertain placements, but they are always seen as something more basal like metriacanthosaurids, piatnitzkysaurids or non-orionidan tetanurines.
*- Metriacanthosaurids are carnosaurs (and carcharodontosauriforms to boot), not outside Avetheropoda.
*- Tyrannotitan is a giganotosaurine, not a basal carcharodontosaurid.
*- Bicentenaria is a non-tyrannoraptoran coelurosaur, not a proceratosaurid.
*- Chilantaisaurus is a megaraptoran, not a metriacanthosaurid. A controversial taxon, but the former identification has been recovered multiple times, and the latter never has.
*- Murusraptor is a megaraptoran, not a pantyrannosaur.
*- Kileskus is a proceratosaurid, not closer to eutyrannosaurs.
- Harpymimus is outside Garudimimidae+Ornithomimidae, not an ornithomimid.
- Alnashetri is an alvarezsaurid, not an avialan.
- Albinykus is sister to Xixianykus, not closer to derived parvicursorines.
- Protarchaeopteryx is an oviraptorosaur, not sister to Pennaraptora.
- Gigantoraptor is closer to caenagnathoids than to Incisivosaurus.
- Nomingia is a ceanagnathid, not outside Caenagnathoidea. And no, I've scored but not yet integrated the synonymy with Elmisaurus.
- Anomalipes is a caenagnathid, not an oviraptorid.
- Yuanyanglong is sister to Avimimus, not to Apatoraptor.
- Nankangia, Huanansaurus and Corythoraptor are citipatiines, not a basal oviraptorids.
- Fujianvenator is an anchiornithine, not an archaeopterygid.
- Alcmonavis is an archaeopterygid, not a dromaeosaurid.
- Overoraptor is an unenlagiine, not a dromaeosaurine.
- Mahakala is a halskaraptorine, not an alvarezsauroid.
- Yandangornis is outside Jinguofortisidae+Ornithothoraces, not a euornithine.
- Vorona is an ornithothoracine, not a confuciusornithiform.
- Novavis, Shangyang, Yuanjiawaornis, Cuspirostrisornis, Sulcavis, Shenqiornis, Alexornis, Navaornis, Gobipipus, Elektorornis, Longchengornis and Liaoningornis are enantiornithines, not outside Ornithothoraces.
- Protopteryx, Elsornis, Xiangornis, Houshanornis, Noguerornis, Liaoxiornis, Largirostrornis and pengornithids are enantiornithines, not euornithines.
- Avisaurus, Mirarce and Gettyia are grouped closely, unlike IW where the former two are widely separated and the latter is a euornithine.

2. Ways in which IW more closely matches the consensus.
*- Eoabelisaurus and Genyodectes are ceratosaurids, not basal ceratosaurs.
*- Rugops is an abelisaurid, not a ceratosaurid.
*- Xenotarsosaurus and Ekrixinatosaurus are abelisaurids, not noasaurids.
*- Deltadromeus, Kiyacursor and Vespersaurus are ceratosaurs, not ornithomimosaurs.
*- Afromimus is a ceratosaur, not an oviraptorosaur.
*- Poekilopleuron and Erectopus are megalosauroids, not megaraptorans. Like Xuanhano and Kaijiango above, these are both controversial, but always megalosauroid or carnosaurian, not megaraptoran.
*- Wiehenvenator is a torvosaur, not a basal megalosauroid.
*- Shaochilong is a carcharodontosaurid, not a megalosauroid.
*- Tameryraptor is a carcharodontosaurine, not a spinosaurine.
*- Neovenator is a carcharodontosaurid, not an allosaurid.
*- Australovenator and Fukuiraptor are basal coelurosaurs, not carnosaurs (in a topology where megaraptorans are coelurosaurs).
*- Phuwiangovenator is by Fukuiraptor and Australovenator, not a maniraptoran.
*- Santanaraptor is a tyrannosauroid, not a compsognathid.
*- Timimus is a tyrannosauroid, not an ornithomimosaur.
- Tugulusaurus is a maniraptoriform, not a compsognathid.
*- Paraxenisaurus is a deinocheirid, not outside Tyrannoraptora.
- Gallimimus is outside Struthiomimus+Dromiceiomimus, not closer to Struthiomimus.
*- Kol is an alvarezsaurid, not a tyrannosauroid.
- Microvenator is a caenagnathid, not outside Caenagnathoidea.
- Rinchenia is a citipatiine, not a basal oviraptorid.
- Anchiornithids are monophyletic compared to archaeopterygids.
- Jinfengopteryx is a troodontid, not a basal paravian.
- Borogovia is closer to troodontines than sinovenatorines.
- Caihong is an anchiornithid, not a dromaeosaurid.
*- Yurgovuchia is a eudromaeosaur, not a tyrannosauroid.
- Hesperonychus (holotype only) is a microraptorian, not a basal avialan.
- Acheroraptor is close to Velociraptor, not a basal serraraptorian.
- Baminornis is an avialan, not an archaeopterygid (in this tree where Archaeopteryx is not an avialan).
- Linyiornis is an enantiornithine, not outside Ornithothoraces.
- Fortunguavis, Cratoavis and Neuquenornis are enantiornithines, not euornithines.
- Brevidentavis is a hesperornithine, not a troodontid.
*- Gargantuavis is outside Aves, not a palaeognath.
*- Cerebavis is outside Aves, not a neognath.

3. Either alternative seems plausible. Obviously most differences fall into this category, but I found these examples most interesting.
- In EW Gualicho is a 'deltadromean', in IW it's a tyrannosauroid.
- In EW compsognathids are a clade, in IW they're a grade (except Scipionyx and "Sinosauropteryx" lingyuanensis).
- Ornitholestes and Fukuivenator are basal maniraptorans in EW, but just outside Maniraptoriformes in IW.
- In EW scansoriopterygids are basal paravians, in IW they're basal avialans.
- In EW the Ukhaa Tolgod troodontid nestlings (IGM 100/972 and 974) are Almas, in IW they're Byronosaurus.
- In EW Hesperornithoides is a troodontid, in IW it's the basalmost serraraptorian dromaeosaurid.
- In EW Bauxitornis is sister to Balaur, in IW it's an enantiornithine.

Deinonychosauria in EW is-

|--+==Anchiornithinae
|  `--Archaeopteryx
`--+--Unenlagiidae
   `--+--Troodontidae
      `--+--Halszkaraptorinae
         `--Serraraptoria

versus in IW-

|--Halszkaraptorinae
`--+--+--Unenlagiinae
   |  `--Serraraptoria
   `--+--Archaeopteryx
      `--+--Anchiornithinae
         `--Troodontidae

So EW keeps anchiornithines in Archaeopterygidae and halszkaraptorines in Dromaeosauridae, but IW keeps unenlagiines in Dromaeosauridae and anchiornithines in Troodontidae. Basal Avialae in EW is-

|--Zhongornis
`--+--Zhongjianornis
   `--+--Sapeornis
      `--+--Jeholornithidae
         `--+--Confuciusornithiformes
            `--+--Balaur+Fukuipteryx
               `--+--Jinguofortisidae
                  `--Ornithothoraces

versus in IW-

|--Sapeornis
`--+--Zhongornis
   `--+--Zhongjianornis
      `--+--+--Jeholornithidae
         |  `--Balaur+Fukuipteryx
         `--+--Confuciusornithiformes
            `--+--Jinguofortisidae
               `--Ornithothoraces

So there's a consensus that Zhongo, Zhongj and Sape are most basal, then Jehol, Bal+Fuk and Conf are in the next grade, then jinguofortisids sister to Ornithothoraces. The EW tree requires the pygostyle to evolve/reverse one less time. Basal Euornithes (reduced to classic taxa for simplicity) in EW is-

|--+--Patagopteryx
|  `--Archaeorhynchus
`--+--Hongshanornis
   `--+--Yanornis
      `--+--+--Songlingornithidae
         |  `--+--Gansus
         |     `--Ambiortus
         `--+--Apsaravis
            `--Ornithurae

versus in IW-

|--Archaeorhynchus
`--+--Patagopteryx
   `--+--Hongshanornis
      `--+--Yanornis
         `--+--Songlingornithidae
            `--+--Apsaravis
               `--+--+--Gansus
                  |  `--Ambiortus
                  `--Ornithurae

Again, there is consensus of Arch and Patag first, then Hong, then Yan, then some combination of the next four with Gan+Ambi forming a clade, then Ornithurae.

Conclusions- So the * in my lists above indicate taxa that are implicated with non-maniraptoromorph clades or Aves. I think it's notable there's almost twice as many 'correct' placements that involve these in IW compared to EW since these are parts of the tree I didn't add characters for. They just depend on the characters that vary within Maniraptoromorpha that happen to also vary in Ceratosauria, Carnosauria and such. So maybe in areas (or analyses) where characters are poorly sampled, IW does better at matching the 'real' tree. Whereas the EW tree had about twice as many 'correct' placements for the taxa I was actually sampling (since all but two of the enantiornithines that were more basal in IW were in a single clade just outside Ornithothoraces, I only counted that point as three differences). 

Another way to compare the trees is which of the differences in the sampled area do I see as probably wrong, and not just my tree being different but perhaps better than the consensus. For the EW tree, I would say Borogovia, Hesperonychus, Acheroraptor and Brevidentavis are probably in the wrong positions compared to the IW tree. For the IW tree, I'd say Harpymimus, Alnashetri, Protarchaeopteryx, Gigantoraptor, Nomingia, Alcmonavis, Overoraptor, Mahakala, Yandangornis, Novavis and Gobipipus are probably in the wrong positions compared to the EW tree. So the EW tree is almost three times better when it comes to differences I subjectively think are probable errors.

In conclusion, based on this experiment I am surprised at how well the IW k=12 analysis did. I'd even say that if you have an analysis with poorly sampled characters, it may be the way to go. But when it comes to the number of 'better' results in the part of the tree the characters are designed for and the number of differences there that I consider to be mistakes, EW performs about twice and about three times better respectively. So I'm sticking with EW, but I'll keep checking the IW results and will stop criticizing k=12 trees as results that are inaccurate.

Reference- Goloboff, Torres and Arias, 2018 (2017 online). Weighted parsimony outperforms other methods of phylogenetic inference under models appropriate for morphology. Cladistics. 34, 407-437.

The Titanosaurus (in?)validity project Part 4 - Bonatitan

Today's taxon to be compared with Titanosaurus in our continuing series is Bonatitan reigi, described by Martinelli and Forasiepi (2004) as based on two partially preserved individuals, but redescribed by Salgado et al. (2015) as five fragmentary individuals, of which a braincase among the material labeled MACN-PV RN 821 is now the holotype. Other elements under that number and MACN-PV RN 1061 are paratypes, including a mid caudal neural arch probably coming from a smaller individual than the holotype. It derives from the Allen Formation of Argentina.

Titanosaurus indicus lectotype GSI 2191 in ventral (top), anterior (left), left lateral (center) (all after Lydekker, 1879) and left lateral (right) views (after Mohabey et al., 2013; scale = 50 mm).

This case is a bit different from the previous three because we have no preserved mid caudal centra for Bonatitan, and the only somewhat comparable caudal neural arch is from a more proximal position than Titanosaurus. As established before, Titanosaurus shows a more distal-esque morphology than saltasaurines in lacking transverse processes and being narrower compared to its length. But I'm still not sure if this makes Titanosaurus the paravian of titanosaurs or saltasaurines the caenagnathoids of titanosaurs (or both?). Regardless, Bonatitan does have well-developed transverse processes based on the lateral articulations on the neural arch, and the broader morphology expected of a saltasaurine, but its features (tall neural peduncle, prezygapophyses with dorsal projection distally) suggest it's around position 4-5 compared to 6-11 in Titanosaurus. And if there were six vertebrae between these, maybe they could transition from a Bonatitan type to a Titanosaurus type. That being said, the width difference still seems implausible to me and the posterior position of the neural peduncle compared to the anterior centrum edge looks to be less than half as much as Titanosaurus, which has also been a consistent trend in saltasaurines.

Bonatitan reigi paratype MACN-PV RN 1061 in anterior (left) and right lateral (reversed; right) views (after Salgado et al., 2015).

Neuquensaurus' caudal sequence has shown that other neural arch characters like the neural peduncle width and posterior shape between the neural arch and centrum are highly variable within an individual, so we can't use those to distinguish Bonatitan and Titanosaurus. For completeness' sake, there is a ~second caudal vertebra preserved with a deep ventral keel over at least the posterior half of the ventral midline (considered diagnostic by both sets of authors), but no taxon so far has described or illustrated if the first two caudals differ from more distal elements in ventral topography (they often do in theropods).

Is Bonatitan Titanosaurus? Probably not, but we're hindered because due to position and incompleteness they aren't that comparable. In particular, the centra seem to be the most positionally consistent in titanosaurs so far within this portion of the tail, and we just don't have one for Bonatitan. There is a diagnostic character listed by both Martinelli and Forasiepi and Salgado et al. involving the vertebra which could be checked in Titanosaurus- "dorsal to middle caudal vertebrae with deep oval to circular pits on both sides of the prespinal lamina", but the published figures and photo of Titanosaurus don't expose the area well enough. This is also a difficulty in comparing Titanosaurus' neural arches- the lack of a dorsal or posterior view, since the short acute triangle with possible prespinal fossa in anterior view in Lydekker's drawing isn't that useful.

Next time- Ibirania.

References- Lydekker, 1879. Indian pre-Tertiary Vertebrata. Part 3. Fossil Reptilia and Batrachia. Palaeontologica Indica (series 4). 1, 20-33.

Martinelli and Forasiepi, 2004. Late Cretaceous vertebrates from Bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae). Revista del Museo Argentino de Ciencias Naturales 6(2), 257-305.

Mohabey, Sen and Wilson, 2013. India’s first dinosaur, rediscovered. Current Science. 104(1), 34-37.

Salgado, Gallina and Paulina Carabajal, 2015 (online 2014). Redescription of Bonatitan reigi (Sauropoda: Titanosauria), from the Campanian-Maastrichtian of the Río Negro Province (Argentina). Historical Biology. 27(5), 525-548.

The Titanosaurus (in?)validity project Part 3 - Rocasaurus

Next up in my series of comparisons with Titanosaurus, to determine its validity, is Rocasaurus muniozi. Named by Salgado and Azpilicueta (2000), it's from the Allen Formation of Argentina. The holotype is a partial skeleton (MPCA-Pv 46) that includes three mid caudals, with paratype vertebrae including two mid caudals (MPCA-Pv 49 and 58). The type material was later described in more detail by Garcia and Salgado (2013), while Fernandez et al. (2025 online) recently published on its caudal histology, using some paratype specimens as well as MPCA-Pv 161 that they call an anterior caudal but is of comparable position to Titanosaurus, and three more fragmentary mid caudals (MPCA-Pv 311-313).

Titanosaurus indicus lectotype GSI 2191 in ventral (top), anterior (left), left lateral (center) (all after Lydekker, 1879) and left lateral (right) views (after Mohabey et al., 2013; scale = 50 mm).

So again, as apparently typical for saltasaurines, we have much wider vertebrae with transverse processes (also apparent in dorsal view of MPCA-Pv 161 not shown below). The first three vertebrae figured below seem to be distal to Titanosaurus' type based on central proportions and neural spine development. Another obvious difference is that most have dual pleurocoels arranged vertically, with Garcia and Salgado noting they are truly lacking in the holotype mid caudal, but that may be positional as it only has slight bumps for transverse processes (as seen in posterior view; Garcia and Salgado call it a posterior caudal). As with the previous two genera, the morphology of the ventral face is especially distinctive, with Rocasaurus having deep and sharply defined oval fossae with a thin median ridge subdividing it in at least its anterior portion. A subtle difference that seems constant in Rocasaurus (also in MPCA-Pv 57) is the double concavity of the dorsal centrum edge posteriorly, unlike Titanosaurus. As in the previous two saltasaurines, the neural peduncle is placed more anteriorly (0-8% of central length vs. 16%) than in Titanosaurus.

Rocasaurus muniozi holotype MPCA-Pv 46 (left; after Salgado and Azpilicueta, 2000), paratype MPCA-Pv 58 (center left; after Garcia and Salgado, 2013), paratype MPCA-Pv 49 (center right; after Fernandez et al., 2025 online) and referred MPCA-Pv 161 (right; after Fernandez et al., 2025 online) in ventral (top) and left lateral (bottom) views.

Salgado and Azpilicueta propose the short ventral concavity (in lateral view) in both preserved caudals of the holotype may be a species-level difference with paratypes MPCA-Pv 57 and 58. Yet the former looks closer to the holotype in my opinion, and all of the specimens figured by Fernandez et al. have the paratype condition where determinable. I would just ascribe this to individual variation. Similarly, while they say the neural arch is placed more anteriorly in these two paratypes, the ratio of centrum posterior to the neural peduncle is <41% and 57% respectively, versus 49% in the holotype. Paratype MPCA-Pv 49's ratio is 49% and referred MPCA-Pv 161 is 50%, so I don't see a correlation with the ventral concavity length. 

The original diagnosis of Rocasaurus muniozi includes "caudal vertebrae with a deep ventral cavity divided by a longitudinal partition", noted above as different than Titanosaurus, and "posterior articulation notably depressed and extended ventrally forward" which is partly the wide shape noted above but also the proposed interspecific difference with paratypes that I think could be individual variation.

So Rocasaurus isn't Titanosaurus. Next up, Bonatitan.

References- Lydekker, 1879. Indian pre-Tertiary Vertebrata. Part 3. Fossil Reptilia and Batrachia. Palaeontologica Indica (series 4). 1, 20-33.

Salgado and Azpilicueta, 2000. Un nuevo saltasaurino (Sauropoda, Titanosauridae) de la provincia de Río Negro (Formacíon Allen, Cretácico Superior), Patagonia, Argentina. Ameghiniana. 37(3):259-264.

Garcia and Salgado, 2013 (online 2011). The titanosaur sauropods from the Late Campanian-Early Maastrichtian Allen Formation of Salitral Moreno, Río Negro, Argentina. Acta Palaeontologica Polonica. 58(2), 269-284.

Mohabey, Sen and Wilson, 2013. India’s first dinosaur, rediscovered. Current Science. 104(1), 34-37.

Fernández, Windholz and Zurriaguz, 2025 onine. Palaeohistological characterisation of the caudal pneumaticity of Rocasaurus muniozi (Sauropoda: Titanosauria). Historical Biology. DOI: 10.1080/08912963.2025.2481526

How not to illustrate your new skeletal reconstruction in its descriptive paper

A brief one today while I finish the Rocasaurus post. So we have a new basal sauropodomorph described from the Late Triassic Santo Domingo Formation of Argentina- Huayracursor (Hechenleitner et al., 2025). All well and good, except when you look at the only anatomical figure in the main paper (it's Nature- you only get one), this is the skeletal reconstruction-

So the post-cervical skeleton is in an oblique anterolateral view. Thus you can't really get a good feel of its proportions, or see elements like the femur, tibia, fibula, etc. in strict lateral view. And they're never figured that way elsewhere either (Extended Data Figure 3 claims to be proximal femora in lateral view, but their Huayracursor drawing is literally a tracing of Figure 2k correctly labeled as cranial view). There's a reason you don't just take a photo of a mounted skeleton at some random angle and use that in your descriptive paper for scientific purposes. For one, most scored characters depend on a standardized perspective if they involve shape, and anterolateral is never involved in my experience. 

But at least a photo saves time on illustrative work, whereas someone went through great effort to create this 3D model of Huayracursor's skeleton. But that makes it so much worse because the model is not actually representative of the anatomy. Most basically, they just made any element represented by some material completely brown, but e.g. the distal scapula, distal metacarpal III, distal manual unguals, dorsal ilium, and distal pubes are all unpreserved. And even worse, in one of the rare cases you can actually check the model against the real anatomy because it happens to be on the same plane, the scapula clearly has a more prominent acromion, a greater distal expansion prior to midshaft, an obtuse angle at the glenoid, etc.. So the anatomy isn't even correct. And Figure 2q shows metatarsals II and III tightly articulated, but the reconstruction has the right foot with their distal ends splayed which I think would be a pretty tragic injury in the living animal. You might as well represent Archaeopteryx with one of those sculpted models of its skeleton, done by somebody who didn't put in the work, and at an oblique angle to boot. It's just scientifically sorta worthless. 

And this one image isn't the end of it. If you check out the Extended and Supplementary Information, we get these-
 

So the upper left is Huayracursor again, but basically useless because now we have an oblique dorsoposterolateral view. But at least it's the actual effing elements as preserved, so here's our equivalent of taking a picture of a museum mount. In the upper right you have the therapsid Exaeretodon sp. "3D rendering with preserved bones in orange, based on preserved specimens CRILAR-Pv 156-160." So besides cranial material, the authors list "CRILAR-Pv 156, ... and right femur. ... CRILAR-Pv 160, ... left femur, left tibia and fibula, metatarsal (?), and other fragmentary remains", and I can't help but notice we only got the CRILAR-Pv 160 femur but also not the tibia, fibula and possible metatarsal, but instead the radius and ulna that don't seem to be preserved. It and the lower right Hyperodapedon take up space in Supplementary Figures S5 and S7, but if I were a rhynchosaur or cynodont worker I would much rather you just photographed another bone or view of an already figured bone there. 

And at bottom left is Extended Data Figure 1a-e, er... the second time. Because Extended Data Figure 1 actually has ten images labeled a, c, e, b, d, a, b, c, d, e.  Good thing Nature is so discerning. The first letters (elements) match the second letters (3D models) taxonomically, but that's not really how figure captions work. In any case, this is the image you put on the magazine cover, or the first and last slide of your conference presentation, but not in your technical publication. It's not even useful in a vague ecosystem illustration sort of way because due to foreshortening and a vague Z axis, their relative size is imprecise.

To sum up- represent your skeletal reconstructions in strict lateral view, and if you use computer models use the elements as preserved instead of idealized creations. Unless your publication literally involves computer models like a study of vertebral articulation or center of gravity, etc.. And if you want to insert a flashy 'cool' 3D model as a figure, 9 out of 10 serious researchers would rather just have another photo of a bone. Check out the description of fellow Late Triassic Argentinian basal saurischian Anteavis (Martinez et al., 2025) for how it's done in a tabloid.

References-  Hechenleitner, Martinelli, Rocher, Fiorelli, Juarez, Taborda and Desojo, 2025. A long-necked early dinosaur from a newly discovered Upper Triassic basin in the Andes. Nature. DOI: 10.1038/s41586-025-09634-3

Martínez, Colombi, Ezcurra, Abelín, Cerda and Alcober, 2025. A Carnian theropod with unexpectedly derived features during the first dinosaur radiation. Nature Ecology & Evolution. DOI: 10.1038/s41559-025-02868-4

The Titanosaurus (in?)validity project Part 2 - Neuquensaurus

Continuing our project, the next taxon is Neuquensaurus australis, first named Titanosaurus australis by Lydekker (1893). It was then separated as "Neuquensaurus" in Powell's (1986) thesis, becoming official in Powel''s (1992) osteology of Saltasaurus*. Neuquensaurus is based on six holotype caudals (MLP Ly 2-6), to which a sacrum (MLP Ly 1, 7) and two more caudals (MLP Ly 48, 66; now lost) were later added (Powell, 2003; D'Emic and Wilson, 2011). Huene (1929) and Powell referred a lot of material to the species, but of that only three unfigured mid caudals and three distal ones were accepted by D'Emic and Wilson. Importantly however, those authors also accept the referral of a partial skeleton described by (Salgado et al., 2005) that includes a "probably" continuous series of proximal to mid caudals (MCS-5/2-MCS-5/15). Both the type and MCS-5 come from the Anacleto Formation of Argentina.

* Or was it? That's how Powell (2003) and D'Emic and Wilson (2011) cite it, but ICZN Article 13.3 states "To be available, every new genus-group name published after 1930 (except those proposed for collective groups or ichnotaxa) must, in addition to satisfying the provisions of Article 13.1, be accompanied by the fixation of a type species in the original publication", and Powell only ever says "Neuquensaurus australis (see Powell, 1986)", "Neuquensaurus australis (Huene, 1929)", "Neuquensaurus australis (Huene, 1929: plate 9)", "Neuquensaurus (= “Titanosaurus”) australis", AND importantly "Neuquensaurus robustus as described by Huene (1929)" and "Neuquensaurus (= "Titanosaurus" robustus, Huene 1929; plate 19: 1)" (all translated). Powell makes australis the type species in his 1986 thesis, but as a thesis that's not recognized by the ICZN. In 2003 he gives australis as the type species, but also credits his 1992 paper for the genus, which is a problem because it's from after 1999, so Article 16.1 kicks in ("Every new name published after 1999, including new replacement names (nomina nova), must be explicitly indicated as intentionally new").

Titanosaurus indicus lectotype GSI 2191 in ventral (top), anterior (left), left lateral (center) (all after Lydekker, 1879) and left lateral (right) views (after Mohabey et al., 2013; scale = 50 mm).

In any case, MCS-5 is convenient because it lets us determine more precisely what caudal the Titanosaurus type belongs to. It seems closest to caudals 6-11 in Neuquensaurus in elongation, prezygapophyseal shape and neural spine development. As in Saltasaurus, all these caudals in Neuquensaurus have transverse processes unlike Titanosaurus, with even the last preserved in MCS-5 (fourteenth) showing some development of one. The centra are so wide I don't think taphonomy can explain the difference this time and further differ in having a concave dorsal cotyle edge. The ventral edge of all Neuquensaurus centra are more concave than Titanosaurus. Ventrally the centra show a broad fossa with no lateral ridges, unlike Titanosaurus that has anterior and posterior grooves delimited laterally with ridges, and a broad and deep median keel in the anteroposterior middle. Like Saltasaurus, the neural peduncle ends more anteriorly in Neuquensaurus (10-11% vs. 16% in Titanosaurus), which is consistent in all comparable vertebrae. The prezygapophyses are low in anterior view as in Saltasaurus.

Neuquensaurus australis holotype MLP Ly 3 (upper left) in ventral (top), anterior (left) and left lateral (right) views (after D'Emic and Wilson, 2011); holotype MLP Ly 5 (upper right)  in ventral (top), anterior (left) and left lateral (right) views (after D'Emic and Wilson, 2011); referred MCS-5 (bottom) caudals 6-11 in left lateral view (after Salgado et al., 2005).

MLP Ly 5b has comparable round and pronounced posterior chevron facets to Titanosaurus, unlike MLP Ly 3, so that difference noted for Saltasaurus could be positional variation. MLP Ly 5b also has a deep concavity to the dorsal centrum posteriorly like Titanosaurus, but unlike other vertebrae of either the type or MCS-5, so this could be individual variation. The shape of the concavity between the neural arch and centrum posteriorly is highly variable, with caudals 8 and 11 of MCS-5 pretty close to Titanosaurus, and caudals 9 and 10 having completely different shapes from one another (acutely pointed vs. rounded), showing this is positional/random variation. While the neural spine is angled more highly compared to the prezygapophysis in Titanosaurus than MLP Ly 5 and the ninth-eleventh caudals of MCS-5, the fifth caudal is comparable, so perhaps the dorsally broken spines of the sixth, seventh and/or eighth were too.

The only caudal character in Powell's (2003) diagnosis is "caudal centra rather short and with a very concave ventral face bounded by rounded edges", which was also mentioned in his 1992 paper that said in Saltasaurus mid caudals "The ventral side has a longitudinal groove much narrower than that seen in Neuquensaurus". As noted above, this is quite unlike Titanosaurus. Salgado et al. add a character from the 1986 thesis "lateral walls of caudal vertebral centra little exposed in ventral view", but this seems the same as in Titanosaurus and was said by D'Emic and Wilson to be present in several other titanosaurs as well. The latter also list "longitudinal ridge below transverse processes" of the mid caudals as diagnostic, which is absent in Titanosaurus. Finally, they list "[postzygodiapophyseal lamina] present and elongate" which is just a gentle convexity in Titanosaurus (seemingly similar to the eighth caudal of MCS-5, but maybe it's just illustrated inaccurately).

Note no caudal material was ever assigned to Neuquensaurus? robustus, so we won't be dealing with it.

So Neuquensaurus isn't Titanosaurus, which even Lydekker recognized was quite possible- "the reference of the latter to Titanosaurus must be regarded as a more or less provisional measure, rendered necessary by our very incomplete knowledge of the type species."  Next up, Rocasaurus.

References- Lydekker, 1879. Indian pre-Tertiary Vertebrata. Part 3. Fossil Reptilia and Batrachia. Palaeontologica Indica (series 4). 1, 20-33.

Lydekker, 1893. The dinosaurs of Patagonia. Anales del Museo de La Plata. 2, 1-14.

Huene, 1929. Los saurisquios y ornitisquios del Cretáceo Argentino. Anales del Museo de la Plata (series 3). 3, 1-196.

Powell, 1986. Revisión de los titanosaurios de América del Sur. PhD Thesis. Universidad Nacional de Tucumán. 340 pp.

Powell, 1992. Osteologia de Saltasaurus loricatus (Sauropoda - Titanosauridae) del Cretácico Superior del noroeste Argentino. In Sanz and Buscalioni (eds.). Los Dinosaurios y Su Entorno Biotico: Actas del Segundo Curso de Paleontologia in Cuenca. Institutio "Juan de Valdes", Cuenca, Argentina. 165-230.

Powell, 2003. Revision of South American titanosaurid dinosaurs: Palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum. 111, 173 pp.

Salgado, Apesteguía and Heredia, 2005. A new specimen of Neuquensaurus australis, a Late Cretaceous saltasaurine titanosaur from North Patagonia. Journal of Vertebrate Paleontology. 25(3), 623-634.

D'Emic and Wilson, 2011 (online 2010). New remains attributable to the holotype of the sauropod dinosaur Neuquensaurus australis, with implications for saltasaurine systematics. Acta Palaeontologica Polonica. 56(1), 61-73.

Mohabey, Sen and Wilson, 2013. India’s first dinosaur, rediscovered. Current Science. 104(1), 34-37.

The Titanosaurus (in?)validity project Part 1 - Saltasaurus

The whole Alamosaurus vs. Utetitan discussion on the Dinosaur Mailing Group made me curious about Titanosaurus' validity, since it's not been tested since Wilson and Upchurch (2003) declared it a nomen dubium in 2003. Their justification was "In summary, all six features forwarded by Lydekker in his diagnosis of T. indicus are now broadly distributed within Titanosauria. ... Because no diagnostic characters could be identified, T. indicus must be regarded as a nomen dubium." But you can't just take an original diagnosis and say "well, those characters are all shared with other taxa, time to sink it" and "we don't see any differences", you have to put in the work yourself to evaluate the existing differences (since no two bones are identical) and show they're at least plausibly individual/positional/ontogenetic/etc. variation. Not only has that never been done for Titanosaurus, there's never even been any suggested taxa it is identical to, of which we would need two to make it indeterminate (because only one identical taxon would make them synonyms). 

So as a little project I decided I'll start from the tip of my sauropodomorph cladogram and go stem-ward, comparing all procoelous titanosaurs with known caudals to see which, if any, could make Titanosaurus a nomen dubium. I'm not a sauropod worker, but at least titanosaur mid caudals have a pretty simple morphology with e.g. no complicated laminae, so the anatomy should be within my grasp. Here's a picture we'll be seeing a lot- the lectotype of Titanosaurus indicus.  Note it is complete except for the fragmented anterior centrum cotyle edge and incomplete neural spine, which would have included the postzygapophyses. Thought to be lost for decades until Mohabey et al. (2013), nobody has figured a posterior or dorsal view.

Titanosaurus indicus lectotype GSI 2191 in ventral (top), anterior (left), left lateral (center) (all after Lydekker, 1879) and left lateral (right) views (after Mohabey et al., 2013; scale = 50 mm).

And our first contender is Saltasaurus loricatus, from the Lecho Formation of Argentina. Described by Bonaparte and Powell (1980) and then in more detail by Powell (1992; 2003), the holotype is PVL 4017-92, a synsacrum fused to both ilia, but mid caudals are represented by up to ten paratype elements including PVL 4017-28, 4017-32 and 4017-33, figured by Powell (1992- Figs. 22-23; 2003- Plate 34, Plate 52 Fig. 3, Plate 53 Fig. 1, 5-6). 

Saltasaurus loricatus paratype PVL 4017-33 in ventral (top), anterior (left) and left lateral (right) views (after Powell, 1992; scale = 100 mm).

Immediately noticeable is despite PVL 4017-33 having a more elongate centrum (length vs. posterior height 2.16 vs. 1.73; a proxy for proximodistal position), Saltasaurus still has prominent transverse processes. Titanosaurus' vertebra is much narrower transversely, but may be taphonomically compressed. Ventrally, Titanosaurus has a median groove anteriorly and posteriorly, but the middle fourth of the ventral midline is so convex it actually protrudes ventrally as a broad keel in both drawing and photo. Both figured Saltasaurus mid caudals instead have a continuous median groove that contains a narrow keel in its middle half. The anterior chevron facets are longer than Saltasaurus', and the posterior chevron facets are distinct circles but not obvious in Saltasaurus. These are apparent in lateral view as a posteroventrally facing surface anterior to the condyle, while Saltasaurus' condyle extends to the posteroventral corner of the centrum. The prezygapophyses are more elongate (especially noticeable in ventral view), and in anterior view form tall triangular processes while Saltasaurus' are very low. The neural peduncle is placed further posteriorly in Titanosaurus (16% of centrum length past the anterior edge vs. 4% in Saltasaurus), which is consistent in all figured Saltasaurus caudals so is not positional variation. The neural peduncle also ends much more anteriorly than Saltasaurus, with 53% of the centrum behind the peduncle compared to 38-39% in Saltasaurus, which combined with the previous ratio makes a narrower peduncle base for Titanosaurus. This posterior peduncular concavity is angled in Titanosaurus (note Lydekker's drawing gets this wrong), but rounded in Saltasaurus caudals until you get to much more distal elements like PVL 4017-38 that have a ridge for a neural spine and an elongation index of 2.62. The centrum also has a deeply concave dorsal border posteriorly unlike Saltasaurus (slightly concave in distal caudals).

Note while PVL 4017-33 has a more basally positioned postzygapophysis than Titanosaurus, PVL 2017-28 does not, so this could be positional variation. The fragmented cotyle edge is why I think we can see the prezygapophyses meet in ventral view, so I'm not counting that as a difference.

So in conclusion, it's pretty obvious Saltasaurus is not Titanosaurus, which is why Powell erected Saltasaurinae in the first place to contrast with Titanosaurinae. His (1992) Saltasaurinae diagnosis includes "The centra of the caudal vertebrae are broader than tall ... The spines of the caudal vertebrae are posteriorly inclined", though the former could be taphonomic for Titanosaurus and the latter is not different between the genera. 

Next up, Neuquensaurus australis.

References- Lydekker, 1879. Indian pre-Tertiary Vertebrata. Part 3. Fossil Reptilia and Batrachia. Palaeontologica Indica (series 4). 1, 20-33.

Bonaparte and Powell, 1980. A continental assemblage of tetrapods from the upper Cretaceous beds of El Brete, northwestern Argentina (Sauropoda-Coelurosauria-Carnosauria-Aves).  Mémoires de la Société Géologique de France. Nouvelle Série. 19, 19-28.

Powell, 1992. Osteologia de Saltasaurus loricatus (Sauropoda - Titanosauridae) del Cretácico Superior del noroeste Argentino. In Sanz and Buscalioni (eds.). Los Dinosaurios y Su Entorno Biotico: Actas del Segundo Curso de Paleontologia in Cuenca. Institutio "Juan de Valdes", Cuenca, Argentina. 165-230.

Powell, 2003. Revision of South American titanosaurid dinosaurs: Palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum. 111, 173 pp.

Wilson and Upchurch, 2003. A revision of Titanosaurus Lydekker (Dinosauria-Sauropoda), the first dinosaur genus with a Gondwanan distribution. Journal of Systematic Paleontology. 1(3), 125-160.

Mohabey, Sen and Wilson, 2013. India’s first dinosaur, rediscovered. Current Science. 104(1), 34-37.