Sunday, December 31, 2023

The Avian Acetabulum: Feduccia grasping at straws

It's not every day that we get an article arguing against the dinosaurian origin of birds any more, with that consensus so strongly supported and many of its detractors being deceased.  But last week Feduccia published "The Avian Acetabulum: Small Structure, but Rich with Illumination and Questions", so in the spirit of the Dinosaur Mailing List of the early 2000s, let's have a fun critique of it.

Feduccia's attempted main point is an exercise in what Makovicky and Dyke (2001) described as naive falsification over twenty years ago - taking some feature shared by birds and dinosaurs and claiming it's not homologous in those groups, and via a mysterious step 2 concluding phylogeny is in shambles and birds must be non-dinosaurian.  Feduccia's (2023) character de jure is the open acetabulum, classic dinosaurian character still seen in birds, and we can use Silesaurus to demonstrate Makovicky and Dyke's entire point that makes Feduccia's argument invalid and useless even if he was correct about the anatomy.

Traditionally an open acetabulum supports dinosaurian monophyly, but I'm a fan of the recent idea that silesaurs are a basal grade of ornithischian and it turns out dun dun DUN silesaurs have closed acetabula.  Thus genasaurs and saurischians most parsimoniously evolved open acetabula convergently.  According to Feduccia's logic, there goes the idea that ornithischians are closely related to saurischians and archosaurian phylogeny must be reevaulated.  But actually no, the vast majority of evidence still strongly supports ornithischians being closer to saurischians than pterosaurs, aphanosaurs, suchians, phytosaurs, etc. because it's not like this example of convergence magically creates evidence ornithischians are related to something else.  That would be naive falsification.

Top- Figure 3a of Feduccia (2023) illustrating (left to right) Stegosaurus, Allosaurus and 'Postosuchus'. Bottom- actual Postosuchus pelvis after Weinbaum (2002).

So anyway, did you know "Late Triassic “rauisuchians” like Postosuchus exhibit an entirely theropodan pelvic anatomy, except for the acetabulum, which is largely closed."?  Because I didn't.  The first thing that's funny is that Feduccia's figure of Postosuchus' pelvis (Fig. 3a) is copied from Figure 15 of Chatterjee's 1985 original description of the genus, and we've known at least since Long and Murry 1995 (TWENTY-EIGHT YEARS AGO) that it's a chimaera using the ilium of Lythrosuchus and the pubis of Shuvosaurus.  It's details like this that demonstrate how Feduccia et al. are stuck in the past.  In any case, Postosuchus has some very non-theropodish pelvic features like the low ilium, huge supracetabular buttress, only two sacral attachments, non-contacting pubis and ischium, absent obturator flange and the characteristic 'rauisuchian' medioventral tilt, but Feduccia doesn't know this because he's stuck in Chatterjee's 1980s world where Postosuchus might as well be a tyrannosaur ancestor.

Right away we get "An open acetabulum is considered one of the most unchallengeable synapomorphies of dinosaurs and birds as opposed to stem dinosauromorphs and dinosauriforms that had not yet achieved fully upright posture and still exhibit a closed or partially closed acetabulum", but as shown by potentially ornithischian silesaurs, nope.  You can go all the way back to Ferigolo and Langer (2007) for the concept, recovered in phylogenetic analyses at least by 2016 by Cabreira et al. and more recently and explicitly argued by Müller and Garcia (2020).  The latter don't even mention the word "acetabulum" because modern phylogenetics has long since moved past "unchallengeable" key characteristics.

Figure 2 of Novas (1996).

Most of Feduccia's paper seems to be written in response to a straw man BAD (Birds Are Dinosaurs) scientist imagining "fully open acetabulum" is to be taken literally, having no medial enclosure at all, and don't you know it, that's often untrue in birds and other pennaraptorans.  In reality, an "open acetabulum" in Dinosauria is contrasted with having only a narrow slit as in Lagosuchus, Ornithosuchus or indeed as illustrated in Chatterjee's 'Postosuchus' chimaera.  Just look at Figure 2 of Novas' classic 1996 work on dinosaur monophyly which shows the dinosaurian perforate acetabulum represented by Herrerasaurus with medial enclosure around the edges just as Feduccia illustrates in so many birds.  Even Feduccia's own figure of Stegosaurus' pelvis (which like his Allosaurus pelvis is ultimately copied from Marsh's papers from the 1800s- such a contemporary reference!) meant to show the "open acetabulum in dinosaurs" has a significant medial rim.  

Meleagris pelvis (top) as redrawn in Baumel and Witmer (1993) from (middle) Harvey et al. (1968), and (bottom) different specimen from Butendiek (1980).

Amusingly, Feduccia says "The Nomina Anatomica Avium, like most modern avian anatomical references, portrays Gallus (domestic chicken) and Anas (domestic duck) with fully open, dinosaurian acetabula, unlike older images (Figure 1), which show substantial medial acetabular walls."  His Figure 1 has drawings of "Gallus, Encyclopaedia Brittanica, 1911; Anas, The Vertebrate Skeleton, Cambridge Press, 1897", which in addition to being downright archaic, are a pop encyclopedia and general vertebrate anatomy book, neither of which seem like somewhere to trust little anatomical details from.  Also, the Nomina Anatomica Avium doesn't even figure the pelvis of Gallus or Anas, it has Meleagris (Figure 4.15).  And that is credited as being redrawn from Harvey et al.'s (1968) Meleagris osteology, which indeed shows a larger acetabular foramen than Feduccia's 1911 Gallus or 1897 Anas.  But maybe it's a fluke.  Let's check Butendieck's 1980 Meleagris osteology and nope, the foramen is even larger there.  Guess it's not a modern cladist conspiracy.

Feduccia insists on staying behind the times when he writes "The continued illogical application of “phylogenetic nomenclature” [70], “phylonyms” [9], and the arbitrary redefinition of established taxon names necessitates the following nomenclatural clarifications. ... “Archosauria” is also used sensu traditum [71,72] and is therefore equivalent to the Archosauriformes of Nesbitt [73], Ezcurra [74], and de Queiroz et al. [9]" and every other work dealing with archosaur phylogeny and nomenclature since the 90s!  Oh, except Benton's (1999) Scleromochlus redescription he cites as reference 72, which proposed the name Avesuchia for the crown group which nobody ever used again.  Why Feduccia insists on using a concept outdated by thirty-some odd years and expects to be taken seriously is a mystery.  Oh, and in his Table 1 Feduccia defines Ornithurae as "All those birds are more closely related to extant birds (Neornithes) than they are to Enantiornithes", so look who's applying phylogenetic nomenclature now.  Guess it can be logical as a concept, who would have guessed?

Top left- unfused Meleagris pelvis showing iliac contribution to the acetabulum (25) is larger than ischial contribution (64) (after Butendieck, 1980). Top right- Sinornis pelvis showing antritrochanter (vant) almost entirely on the ilium (after Sereno et al., 2002).  Bottom- Buitreraptor (left) and Berlin Archaeopteryx (right) showing antitrochanters (at) (after Agnolin and Novas, 2011).

It's not just acetabular closure that Feduccia is examining, he also comments on the distribution of supracetabular crests and antitrochanters.  For the latter, he notes "A structure homologized with the avian antitrochanter has been reported in ... a miscellany of coelurosaurs [16,102,103]. There is no osteological evidence that these structures are homologous: the avian antitrochanter forms primarily
[69] or almost exclusively [90] from the ischium, whereas the so-called “antitrochanters” of these nonavian taxa are almost exclusively iliac in composition ... Moreover, while continuity of function is not a requirement of homology, it should be noted that putative “antitrochanters” of so great a range of taxa cannot possibly have performed the specialized mechanical role that the true antitrochanter does in extant birds as part of their peculiar hindlimb locomotory system [90,104]."  So the antitrochanters of coelurosaurs aren't actually antitrochanters because they're on the ilium!  But wait, let's pull out Butendieck's turkey osteology again, and oh no!  Meleagris has an antitrochanter mostly formed by the ilium!  And while Feduccia says "In both enantiornithines and ornithurines, the maintenance of balance in obligately bipedal locomotion is linked to the presence of an antitrochanter", Sereno et al. (2002; in a figure Feduccia specifically cites) shows that in the enantiornithine Sinornis the antitrochanter is almost entirely on the ilium despite supposedly having the same function as in living birds!  That's also true in the Lecho Formation enantiornithine pelvis PVL 4042 by the way (Walker and Dyke, 2010: Fig. 14).  Given even those three examples, when Feduccia says "The putative “antitrochanters” of alvarezsaurs and therizinosauroids are iliac in composition", or that in Rahonavis "the purported antitrochanter, however, is iliac in origin", it lacks any force of argument whatsoever.  Since it CAN be that way in birds and even supposedly have the same function, it can also be that way in bird ancestors and relatives.

Similarly, for Archaeopteryx Feduccia claims "Agnolin and Novas [115] (Figure 3B) interpreted a slight swelling on the posteroventral rim of the acetabulum in the Berlin specimen as an antitrochanter, but this interpretation seems incorrect because (1) it is positioned on the posteroventral rim of the acetabulum, whereas the avian antitrochanter is posterodorsal to the acetabulum [69,90,104]; it is composed solely of the ilium, whereas the avian antitrochanter is composed exclusively or principally from the ischium."  But as the ischial peduncle doesn't wrap beneath the acetabulum, the structure is clearly on the posterodorsal rim, and is furthermore basically identical in structure and position to that of Sinornis (and Buitreraptor shown next to it, contra Feduccia's claim unenlagiids lack antitrochanters) except for being a bit more slender than in Sinornis.  How Feduccia can have looked at these figures and think Sinornis has an antitrochanter but Archaeopteryx does not is beyond me.  Another example of Feduccia's confusion is when he states "Avimimus portensosus [sic], however, possesses an ischial antitrochanter that, therefore, appears homologous with that in birds" but then notes A. nemegtensis was diagnosed in part by Funston et al. (2018) as lacking an antitrochanter.  Yet Funston et al.'s same figure cited by Feduccia shows the antitrochanter in A. portentosus is largely on the ilium (as Figure 4G doesn't even show the ischium) and indeed, A. nemegtensis doesn't preserve a proximal ischium at all so if the antitrochanter were ischial neither Funston et al. nor Feduccia would even know it lacked one!  The basic conclusion is Feduccia doesn't know what he's looking at, making his attempted review of antitrochanter distribution useless.

Feduccia is no better when discussing supracetabular crests, as evidenced when he says "Although Paul (2002) claims that a supracetabular crest is present in archaeopterygids, it is absent in the London, Berlin, Eichstatt and Munich specimens (Figure 8d)."  But Paul's Plate 24Ab clearly shows a convex outer rim in ventral view that defines a supracetabular crest in a photo of a cast of the London specimen, whereas Feduccia's Figure 8d is a horizontally oblique drawing of a reconstructed generic Archaeopteryx pelvis that couldn't show lateral convexity in dorsal/ventral view even if it was there.  So far from countering Paul, the medium is inferior, the subject is inferior, and the perspective would make evaluation impossible in any case.  Indeed, Paul's entire Plate 24 is an effective argument against everything Feduccia claims about antitrochanters and supracetabular crests, showing for example that tyrannosaurids lack a supracetabular crest, so apparently it wasn't integral to a functioning theropod gait, and that young Meleagris lacks an ossified antitrochanter, so maybe at least some of these theropods with seemingly small or absent antitrochanters had larger cartilaginous structures that enabled them to be functionally similar to living birds and/or Avimimus portentosus.

Right- Feduccia's (2023) Figure 5 (caption below). Top left- Megapnosaurus rhodesiensis pelvis (after Raath, 1977- see, I can cite old papers too!). Bottom left- Oksoko pelvis (flipped horizontally, after Funston et al., 2020).

My favorite part of this paper though is Figure 5, which shows drawings of the "Pelvis of the basal theropod Coelophysis (a) compared to an array of primarily ground-dwelling birds: (b) Solitary Tinamou (Tinamus solitarius), (c) Wild Turkey (Meleagris gallopavo), (d) Japanese Quail (Coturnix japonica), (e) Greater Roadrunner (Geococcyx californianus), (f) Emu (Dromaius novaehollandiae), (g) Bush Moa (Anomalopteryx didiformis), and (h) Elephant Bird (Aepyornis hildebrandti)."  The first thing of note is that the Coelophysis drawing is highly inaccurate, being a copy of Colbert's (1989) illustrations by Lois Darling, which "do not depict the anatomy of Coelophysis accurately" (Downs, 2000).  There are no pubic or obturator foramina, no obturator plate on the ischium, the supracetabular crest is not confluent with the ventral postacetabular edge, and rather importantly for this paper's subject the ilium is lacking the medial wall on the dorsal part of the acetabulam (that is partially ovelapped laterally by the supracetabular crest) and the large antitrochanteric surface formed by the ischial peduncle and ischium.  While I agree with Feduccia the latter structure is not homologous to the maniraptoran antitrochanter (which is on the outside rim of the acetabulum), it does combine with the dorsal section to make a significant surface medial to the acetabular rim.  Again, Feduccia is using a 30+ year old source that is well known to be wrong.

And what's even the point of the figure?  "Note the contrast between the condition in these cursorial birds, which presumably should most closely approach the putatively ancestral theropod condition with respect to their acetabular morphology, and the condition in Coelophysis."  First of all, why should an avian/neornithine anatomy that evolved in the Late Cretaceous converge with or regress to a Triassic group's morphology?  Second, modern birds have a functionally different gait from non-maniraptoriform theropods like coelophysoids at least, where the femur is more horizontal and less mobile, so even in terrestrial birds I don't see why any special acetabular anatomy would be similar.  Third, Feduccia thinks oviraptorosaurs are birds (e.g. Feduccia and Czerkas' 2015 "Testing the neoflightless hypothesis: propatagium reveals flying ancestry of oviraptorosaurs") and oviraptorids like Oksoko happened to have an even more open acetabulum than Darling's fake Coelophysis and a pelvis much more superficially similar to coelophysoids than to modern birds.  So according to Feduccia, some cursorial birds DID approach what he imagined the ancestral theropod condition to be like.  He just chose to only figure cursorial crown birds, which aren't very similar to coelophysoids in pelvic structure.

Looks like my work in the Lori description (Feduccia's reference 52) got cited! "Reliance on simple tabulations of step count difference between constrained and unconstrained trees [52] to determine whether the most basal members of pennaraptoran clades have been correctly resolved by parsimony analysis of current data matrices is naive and takes no account of the statistical significance of differences in tree populations [50]."  Oh noes!  I was naive!  And what's this reference 50 I should have taken into account?  James and Pourtless 2009!  The study that actually found birds as maniraptorans, coelurosaurs, theropods and dinosaurs, but which hid it by only figuring majority rule bootstrap trees and always pruned out Effigia because it falling out as an ornithomimosaur was too embarrassing of a result even for them!  And that was even after scoring all dinosaur manual characters as unknown, even in the pentadactyl Eoraptor and Herrerasaurus with zero controversy of digital homology!  Bwa ha ha!  Yeah, those are some methodologies I really should have taken to heart.  Hey, at least Feduccia cited me as the correct author this time!

Top- Ornitholestes holotype ilium and proximal pubis (after AMNH's 2007 digital collections). Middle- Allosaurus USNM 4734 ilium (after Gilmore, 1920). Bottom- Tyrannosaurus FMNH PR2081 ilium and sacrum (after Brochu, 2003).  Note even the latter classic theropod has significant medial walls on the peduncles.

But what does any of this have to do with birds not being dinosaurs?  Feduccia spends lots of time discussing the amount of acetabular closure in modern birds, always emphasizing the medially walled areas, and going so far as to say "it is more difficult to adequately assess acetabular morphology in extant birds than is generally realized. Preparatory methods used to produce skeletal collections in museums (e.g., defleshing with dermestid beetles, oxidation methods involving HO, and ammonia, chemical bleach, and maceration) can damage or destroy fragile anatomical features" so that we can't even trust our own specimens!  It's as if in his typological mind, this is making birds "less dinosaurian" because dinosaurs are things with open acetabula, and shouldn't this be concerning to us BADists?!  No.  No it should not.  Hell, all crown birds could have fully closed acetabula like derived ankylosaurs and it wouldn't matter one bit because key characters aren't a thing and evolution happens.  Just like it doesn't make ankylosaurs any less dinosaurian.  We wouldn't even need the fact that every single stem bird fossil* has an open acetabulum regardless of preservation, and that makes it undeniable that regardless of the condition in crown birds, and regardless of what birds evolved from, Mesozoic birds have open acetabula.

* Even scansoriopterygids which he lies about, claiming "they have closed acetabula" when even his previous description with Czerkas (2014) cited "the partially open acetabulum in Scansoriopteryx."  Czerkas and Yuan's (2002) original description also states "the indication from the texture and color extending from the ilium suggests that the hip socket was not as widely perforated as in theropods or dinosaurs in general. The inner edge of this reduced perforation in the hip socket can be seen in both acetabula on the counterslab."

Feduccia will emphasize "partially closed" in many examples, but non-pennaraptoran theropods are not the monolith he takes them for when as in 2014 he and Czerkas write "theropod dinosaurs, invariably exhibiting a completely perforated and open acetabulum", or as he says in the present paper "The condition in the large Jurassic tetanurine Allosaurus (Figure 3) may be taken as stereotypical of its development in Theropoda", with Figure 3 being redrawn from the 1880s.  Just check out classic theropod Ornitholestes above with a medial wall taking up almost half of the acetabular circle.  Even in Allosaurus itself, if you look at an actual photo you can see that Figure 3's seemingly uninturrupted dorsal edge is wrongly drawn and that half the ischial peduncle is medial as is some of the pubic peduncle but most of that is hidden by the laterally overlapping supracetabular crest except for the posteroventral corner.  Dinosaurs all over the cladogram were changing the amount of medial acetabular ossification and birds were no exception.

And really, the takeaway I got from Feduccia's data is that just like most characters, the development of acetabular closure, supracetabular crest extent and antitrochanter size are labile and prone to homoplasy.  They are not integral parts of a locomotory system, and similar taxa can manage movement just fine when these variables are changed.  That's why you can have Avimimus portentosus and A. nemegtensis with such drastic differences in antitrochanter development, which Feduccia seems baffled by- "it is not clear why a single genus should be polymorphic for this character state, it is difficult to interpret this character conflict."  Similarly Feduccia says "It is surprising, given the
frequent characterization of birds as having — like dinosaurs — completely open acetabula to
discover that rotisserie [chicken] specimens have partially closed acetabula with a perforation covered
by soft tissue."  Are we assuming Mesozoic dinosaur acetabular foramina were not covered by soft tissue?  And is there really a functional difference between the paper thin medial bone walls Feduccia is worried might be present in modern birds but destroyed by preparation and a fibrocartilage wall hypothetically present in a theropod with an open bony acetabulum?  Based on Feduccia's described variation within modern birds, I'm doubtful.  But he's so obsessed with these being typologically enforced key characters essential to function and evolutionary history, for both himself and his BAD straw man, that them being not all that important in anathema to him.

Now, this is out of order but I wanted another figure to liven up the post.  On the left is "Late Jurassic Archaeopteryx (image composites of varied sizes, primarily after P. Wellnhofer, based primarily on the Munich specimen, with details from the London, Berlin, and Eichstitt specimens;".  Yeah, there is no closing parenthesis and I think "image composites of varied sizes" refers to the Gansus, Qiliania and Pterygornis pictures featured elsewhere in this figure.  More importantly as noted far above, this figure is just a drawing (by K. Grow apparently) of a hypothetical composite, and while it is used as an argument against a supracetabular crest in the genus it is incapable of showing the development of a supracetabular crest directed at the viewer as in e.g. Ornitholestes.  On the right is an item labeled "Microraptor, the Early Cretaceous four-winged bird-like glider (dromaeosaur), considered by many an early bird. (Microraptor photo courtesy D. Burnham)", but some digging finds this is actually the structure labeled "Right lateral view of microraptoran pelvis (modified cast)" in Burnham's (2007) thesis.  The latter claims it is "based on a recent transfer preparation of a Chinese microraptorine, which exposes a lateral view of the acetabulum."  Who knows what parts were modified and we have no traceable specimen to confirm anything with, although the preacetabular process and ischial tip don't look like those in actual Microraptor fossils.  I'm not even implying any purposeful anatomical inaccuracy, just noting that Feduccia passed off a "modified cast" as an apparently real specimen.

In the end, Feduccia admits that if "the first birds — and at least taxa like the microraptorines — were not terrestrial cursorial bipeds, like theropods, but trunk-climbing gliders" it "would be consistent with arguments that (at least some of) these taxa are “neoflightless” theropods, whose immediate ancestors underwent transformations in the theropod locomotory system (perhaps because of a shift to arboreality)."  But he rejects this, in part due to "the discovery of a “tetrapteryx” stage in early aviation evolution", which is a Petersian thing to say because not even the relatively well resolved pennaraptoran consensus phylogeny views the tetrapteryx stage as an established thing, let alone Feduccia's wacky world of uncertainty where who knows how oviraptorosaurs, troodontids, eudromaeosaurs, microraptorians, unenlagiids, anchiornithines and archaeopterygids interrelate.  Sure microraptorians have big leg wings, and Sapeornis and anchiornithines have a much shorter version, but the former are dromaeosaurids and the latter are maybe archaeopterygids, maybe avialans, maybe troodontids.  The structures are lacking in Caudipteryx, troodontids, Archaeopteryx and pygostylians, so in order for a tetrapteryx stage to exist, dromaeosaurids and/or anchiornithines would have to be ancestral to crown birds somewhere or we have a lot of reversals.  Note Feduccia claims "if Jinfengopteryx is, in fact, a basal troodontid [140,236] (but see discussions in [115,139,162]) then troodontids also primitively exhibited a “tetrapteryx” bauplan", but Jinfengopteryx has no long leg feathers at all, not even long tibiotarsal ones like Archaeopteryx and basal pygostylians.  So that's just him being wrong again.

And in part the rejection is due to... it's really not made clear.  Feduccia assumes us BADists are as constrained by imagined evolutionary just-so stories as he is, claiming we are bound to "the argument — advanced since Huxley, championed by Ostrom, repeated ad infinitum — that the obvious reason birds are obligate bipeds and that they never passed through an evolutionary phase in which all four limbs were integrated into the flight mechanism, is that birds are descended from obligate bipeds, viz. theropods."  But he already said a facultatively bipedal stage (around the paravian stem maybe?) due to arboreal habits would still be consistent with a theropod ancestry, as quoted in the prior paragraph.  Feduccia continues "These data instead suggest that the reason bipedalism in birds differs fundamentally from bipedalism in all other archosaurs [does it?] ... is that birds started their evolutionary trajectory toward obligate bipedalism from a different starting point than the system employed to such success by dinosaurs."  But poposaurs and dinosaurs (or alternatively saurischians and Lesothosaurus+genasaurs) started their obligate bipedalism trajectory via facultative bipeds with a more sprawling stance, more closed acetabula, no antitrochanter and less inturned femoral heads just as Feduccia believes birds did.  It's just special pleading to claim they are "fundamentally different."  Finally, he claims "This is a logical explanation for the surprising persistence of medial occlusion of the acetabulum in many pennaraptorans and the absence, in most, of either well-defined supracetabular crests or antitrochanters."  This despite explicitly saying two pages ago "Oviraptorosaurs uniformly display fully perforate acetabula" and "Troodontids have fully perforated acetabula", so by "many pennaraptorans" Feduccia really just means dromaeosaurids.  He also said on the previous page "Compsognathids are “prototypical” small theropods [221], yet they lack a supracetabular crest or antitrochanter", so why would this be surprising in most pennaraptorans?  (lacking a hypertrophied antitrochanter like ornithurines at least...)

Amusingly enough, the most vehement objections to BAD are in Feduccia's Figure 7 caption showing hesperornithid pelves.  This claims without supporting data "the acetabula show that they are definitively not allied with dinosaurs" and "Hesperornithiforms are often termed diving dinosaurs, but given their acetabula anatomy this designation is erroneous."  I'd think such late and specialized divers would be of little relevance, but what do I know...  Hey that long and low postacetabular process is looking pretty similar to Postosuchus.  Maybe we've found our archosaurian avian ancestor ;)

And that's it.  Feduccia's Conclusion is "The hypothesis that birds are maniraptoran theropod dinosaurs, despite the certitude with which it is proclaimed, continues to suffer from unaddressed difficulties [29-31,50,237]", with references 29-31 being his own books and paper, 50 we recall is James and Pourtless' terrible TERRIBLE attempt at a cladistic analysis, and 237 is James' fawning review of Feduccia's latest book.  Ha.  You know what's an unaddressed difficulty in Feduccia's hypothesis?  Thirty-plus years since he publically doubted the dinosaurian origin of birds, we still have pennaraptorans emerging from some mysterious lineage of Triassic archosaur(-iform)s.  And yet we've closed the gaps so well in theropod phylogeny that the precise relationships among basal avialans, basal paravians, basal pennaraptorans, basal maniraptorans/-iforms, basal neocoelurosaurs, basal coelurosaurs, etc. are controversial due to homoplasy.  Surely any day now we'll find the evolutionary intermediates between Middle Jurassic scansoriopterygids and Triassic ???????.  Anything But a Small Running Dinosaur indeed.

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Walker and Dyke, 2010 (as 2009). Euenantiornithine birds from the Late Cretaceous of El Brete (Argentina). Irish Journal of Earth Sciences. 27, 15-62.

Agnolin and Novas, 2011. Unenlagiid theropods: Are they members of the Dromaeosauridae (Theropoda, Maniraptora)? Anais da Academia Brasileira de Ciencias. 83(1), 117-162.

Czerkas and Feduccia, 2014. Jurassic archosaur is a non-dinosaurian bird. Journal of Ornithology. 155(4), 841-851.

Feduccia and Czerkas, 2015. Testing the neoflightless hypothesis: Propatagium reveals flying ancestry of oviraptorosaurs. Journal of Ornithology. 156(4), 1067-1074.

Cabreira, Kellner, Dias-da-Silva, da Silva, Bronzati, de Almeida Marsola, Müller, de Souza Bittencourt, Batista, Raugust and Carrilho, 2016. A unique Late Triassic dinosauromorph assemblage reveals dinosaur ancestral anatomy and diet. Current Biology. 26(22), 3090-3095.

Funston, Mendonca, Currie and Barsbold, 2018 (online 2017). Oviraptorosaur anatomy, diversity and ecology in the Nemegt Basin. Palaeogeography, Palaeoclimatology, Palaeoecology. 494, 101-120.

Funston, Chinzorig, Tsogtbaatar, Kobayashi, Sullivan and Currie, 2020. A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria. Royal Society Open Science. 7: 201184.

Müller and Garcia, 2020. A paraphyletic 'Silesauridae' as an alternative hypothesis for the initial radiation of ornithischian dinosaurs. Biology Letters. 16(8), 20200417.

Feduccia, 2023. The avian acetabulum: Small structure, but rich with illumination and questions. Diversity. 16, 20.

Friday, October 27, 2023

SVP's big mistake to make a separate virtual conference this year

Due to the pandemic, SVPs 2020 and 2021 were great for people like me who can't afford to travel to it, pay for the registration and lodging, and miss work for that long (I did go in person back in 2001 and 2002 when I unwisely used student loans to afford it... still paying those off...).  We got to see all the cool new discoveries for a few hundred dollars and could do so at our leisure without missing concurrent talks, rewatch things we missed, and talk with the presenters without the physical hassles.  Then last year they decided to make the online portion optional, so that most of the people with talks I wanted to see didn't upload anything and if I recall correctly, only two of the theropod sessions' presentations were even available.  But at least the posters were all there to view, since those require basically no effort to upload unlike narrating a Powerpoint presentation.  It was still very disappointing for paying the non-member's United States-based fee of $300.

This year, SVP decided to make a separate virtual conference from its old-style physical conference.  I was hesitant after seeing most of the power players back out of showing anything last year when given the option (I still have no idea what Ruebenstahl et al. proposed about Coelurus...), but you don't know what you're missing if you don't try it.  So I paid the slightly lower fee of $200 and yesterday the virtual meeting started and ... what a waste.

The website states "We will still have posters, but they will be in an organized virtual poster hall you can walk around and explore."  But what we didn't know until the abstract book came out (conveniently when refunds were also no longer possible) is that only 38 of these are "virtual posters" and that everyone else had the option to let their poster be uploaded but didn't have to.  And what we didn't know until yesterday is that only 92 of the 323 normal poster authors agreed to upload their posters to the virtual meeting.  That's 28% and includes a whopping FOUR Mesozoic theropod posters, only two of which (the Wessex megaraptoran braincase and the Yellow Cat allosauroid teeth) I really care about.  Didn't get Cruz Vega et al.'s Hell Creek avian, Hall et al. on Bistahieversor pneumaticity, Rhynard et al. on Allosaurus jimmadseni internal skull anatomy, Bugos and McDavid on juvenile Coelophysis, Voris et al on Atrociraptor frontals, Takasaki et al. on troodontid intermandibular joints or Perry et al. on Nanuqsaurus validity.  Not that those would have justified the $200 price point either (for comparison last year's "very disappointing" virtual meeting still had about fifteen interesting theropod presentations/posters), but it would have been better!

Of course the big missing piece was having none of the 305 talks uploaded.  No Coppock et al. or Carr and Brusatte on Daspletosaurus species, Slowiak-Morkovina et al. on Bagaraatan, Makovicky et al. on a giant Mussentuchit caenagnathid, Lamanna et al. on unenlagiine Imperobator, Ruebenstahl et al. on Velociraptor species, Maddox et al. on a Hell Creek unenlagiine or Hohman et al. on Two Medicine dromaeosaurid variation, and that's just page 56 of the abstract volume.  Not only were most of the most interesting presentations given as talks, but a talk is far more engaging than a poster.  It's ten to fifteen minutes long, whereas even the most text-dense posters take maybe a couple minutes to read, and most much less.  Similarly, talks are more entertaining than posters, which means I ended up watching a lot of talks from SVPs 2020-2022 that were outside my area of expertise, and learned more.  But I have about as much interest in reading a poster on unfamiliar material as I do reading a paper on it.  So instead of a potential ~61 hours (305 talks times 12 minutes) of entertainment just from talks alone, we got 130 posters which took a few hours to get through.  For comparison, that was ~70 hours for $300 in 2020 and 2021 versus ~3 hours for $200 this year.

Finally, SVP got the Q&A part down perfectly in 2020 and 2021 with a chatroom for each presentation.  In real life, you have to either awkwardly raise your hand for the limited minute or so after the talk and hope to be called on or track down the author during the meeting and hope they're not having a more important conversation if you find them.  But in 2020 and 2021, if you have any question you can just post it and the author will see it at some point and reply, with time to formulate a good answer.  Now in 2023 we have the virtual Sternberg Museum where we have to talk in real time while our avatars are next to each other and any author may be there or may not be at any given time, and if they aren't one of the authors of the 38 virtual posters have no obligation to be there at all.  And just like in real life, if you do happen to track one down they may be in one of the numerous virtual tables that are private chat rooms, so I guess you watch your avatar wait for them to get up?  Or maybe it's possible to interrupt the private chat awkwardly?  After checking, not even the virtual poster authors have any obligation, as they are merely "welcome to stand with their poster at any time".  With the average abstract having three authors are we supposed to keep track of all the authors of all the abstracts we are interested in and keep checking the Participants bar to potentially chat with them?  It'd be simpler just to email or Facebook message authors at this rate.  It reminds me of that meme of shopping in the metaverse where you have to push a virtual cart and turn to pick up virtual items instead of just selecting from a list like every online retailer - SVP has recreated the bad parts of in person Q&A for its virtual world.

"But wait!", you say.  What about the online components that aren't talks or posters?  They exist in hour or two hour intervals, and weren't announced until 10 pm Wednesday, approximately zero days before the meeting began.  So while it would be easier to find participating dinosaur authors at the 'Networking Social: Dinosaur Research' between 6 and 8 pm Friday, I gotta work and had no time to plan around it.  Besides that, 'Discussion Panel: State of the Dinosauria' might be interesting to watch (happening the hour before I work Friday, so I'll get to be there for the first 45 minutes), but this and the other Zoom presentations were stated to be uploaded to YouTube later so aren't really perks of attending the meeting.

Waiting for Choiniere's talk 30 minutes before it began, but I don't think it was even here and I had to use a link from an email instead.

Thus while $740 gets you up to 25 hours of talks (since in real life there are three sets of twenty-six 15 minute talks happening simultaneously every day) and 453 posters (let's say at 2 minutes per poster that's 9 hours to digest them all) plus all the in person events and online events, $200 gives you 130 posters that might take three hours to digest and the same online events.  Even ignoring the in person events and quality of talks over posters, you're getting 9% of the time from the online meeting while spending 27% of the cost.  $740 times 9% is $67.  A pretty far cry from $200.

Honestly, for the last three SVPs I've spent days viewing everything I wanted to whereas this year I was done in a few hours of virtual walking to each poster in order.  I watched Choiniere's Elliot Formation talk right before posting this (which was fine), will catch most of the dinosaur panel before work Friday, then probably watch the squamate panel Saturday and mammal panel Sunday because I want to feel some sort of relevance for my expenditure, but that's literally everything I'm remotely interested in.  I'd say the value is maybe $30.  It's sad.

Let's end this on a positive note though - how to improve things for future years.  The number one message that should have obviously been learned from this year and last is to UPLOAD EVERY TALK AND POSTER.  I get that not everyone has the equipment or skills, so just have SVP record the live talks and post those with an option for the authors to upload a high resolution version of the slideshow too.  To make it more engaging, have the presentation sessions from each room be streamed live via Zoom, then the talks broken up to be watched separately later.  For those 72% of presenters who are apparently paranoid someone is going to somehow get away with stealing your ever so tweet-worthy study on Deinonychus histology or whatever, I'm pretty sure nothing has been claim-jacked from SVPs 2020 or 2021 despite people having years to do so.  What's ironic is that SVP solved one of its main problems with technology- there are too many talks to view them all in person because they have to host three sets simultaneously, but by hosting them all online as videos on demand everyone can watch all of them.  Then this year they killed that solution and made the world worse for all the attendees with a return to artificial scarcity.  The second message is bring back the chatroom Q&A.  It was perfect and now you've recreated all the bad parts of in person interactions with new negatives like authors not even needing to be in the available space.  So again you've solved the real life problems with technology then just brought them back for no reason.

COVID 19 forced SVP to update to the Shiny Digital Future, but now it's backsliding to be more tedious for everybody.  Even the SVP members who get paid to attend via their institutions now again have to decide what talk room to attend, can't watch talks on their own time, can't rewatch talks, have to track down authors, etc..  2020 and 2021 showed us you can deliver a quality digital conference, please do it again in 2024.  Or if you insist on being as archaic as your material of interest, charge an order of magnitude less for that option.

Sunday, July 9, 2023

New data on African abelisaurs

Hi everyone.  I'm a coauthor on a paper published this week reviewing the record of African abelisauroids (de Souza-Júnior et al., 2023).  I want to thank André Luis de Souza-Júnior for adding me, as he used The Theropod Database as a resource.  That's how you do it!  We incorporated my corrections and suggestions back in 2020 before it was submitted, but as is typical of these projects there have been new discoveries since.  Here are some additional records-

unnamed Abelisauroidea (Lasseron, 2020)
Early Bathonian, Middle Jurassic
GEA 6, Guelb el Ahmar, Anoual Formation, Morocco
- (MNHN GEA6-5) lateral tooth (2.58x1.86x1.39 mm)
Early Bathonian, Middle Jurassic
GEA 7, Guelb el Ahmar, Anoual Formation, Morocco
(MNHN GEA7-14) lateral tooth (3.75x2.51x1.59 mm)
(MNHN GEA7-17) lateral tooth (2.60x2.06x1.09 mm)
Comments- Discovered in 2015 and/or 2018, Lasseron (2020) concluded "The convexity of the two carinae is a remarkable feature. It recalls the Abelisauridae (Smith, 2007; Hendrickx & Mateus, 2014), but also the Noasauridae (Carrano et al., 2002), an identification which would be consistent with the small size of these teeth. We therefore attribute these teeth to an Abelisauroidea gen. and sp. indet." (translated).
Reference- Lasseron, 2020. Paleobiodiversite, evolution et paleobiogeographie des vertebres mesozoiques africans et gondwaniens : apport des gisements du Maroc oriental. Doctoral thesis, Museum National D'Histoire Naturelle. 493 pp.

unnamed abelisauroid (Lasseron, 2020)
Berriasian, Early Cretaceous
Ksar Metlili, Ksar Metlili Formation, Morocco
- (FSAC-KM-A1-12) lateral tooth (3.41x2.26x1.47 mm)
Comments- Collected in 2010, 2015 or 2018, Lasseron (2020) concluded "The convexity of the two carinae is a remarkable feature. It recalls the Abelisauridae (Smith, 2007; Hendrickx & Mateus, 2014), but also the Noasauridae (Carrano et al., 2002), an identification which would be consistent with the small size of these teeth. We therefore attribute these teeth to an Abelisauroidea gen. and sp. indet." (translated).
Lasseron, 2020. Paleobiodiversite, evolution et paleobiogeographie des vertebres mesozoiques africans et gondwaniens : apport des gisements du Maroc oriental. Doctoral thesis, Museum National D'Histoire Naturelle. 493 pp.

undescribed possible abelisauroid (Smith, Lamanna, Dodson, Attia and Lacovara, 2001)
Cenomanian, Late Cretaceous
Bahariya Oasis, Baharija Formation, Egypt

Material- teeth (FABL 7.5 mm)
Comments- These "recently recovered" teeth are stated to have significantly more serrations per mm than similarly sized Deinonychus or Dromaeosaurus and have "denticle morphologies and the average crown base width (CBW) and CBL9crown base length] relationships ... more reminiscant of abelisaurids than dromaeosaurids."
Reference- Smith, Lamanna, Dodson, Attia and Lacovara, 2001. Evidence of a new theropod from the Late Cretaceous of Egypt. Journal of Vertebrate Paleontology. 21(3), 102A.

Kem Kem noasaurid cervical FSAC-KK-5016 in (A) right lateral, (B) left lateral, (C) anterior, (D) dorsal, (E) ventral and (F) posterior views (after Smyth et al., 2020). Scale = 10 mm.

unnamed Noasauridae (Russell, 1996)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco

Material- (CMN 41873; bone taxon H) distal humerus (48 mm wide) (Russell, 1996)
(FSAC-KK-5016) (~1.5 m) incomplete ~fourth cervical vertebra (21 mm) (Smyth, Ibrahim, Kao and Martill, 2020)
Comments- The humerus is very similar to Masiakasaurus.
References- Russell, 1996. Isolated dinosaur bones from the Middle Cretaceous of the Tafilalt, Morocco. Bulletin du Museum national d'Histoire naturelle. 18, 349-402.
Smyth, Ibrahim, Kao and Martill, 2020 (online 2019). Abelisauroid cervical vertebrae from the Cretaceous Kem Kem beds of southern Morocco and a review of Kem Kem abelisauroids. Cretaceous Research. 108, 104330.

Kem Kem abelisaurid axis FSAC-KK-5015 in (A) right lateral, (B) left lateral, (C) anterior, (D) dorsal, (E) ventral and (F) posterior views (after Smyth et al., 2020). Pink area is filler. Scale = 20 mm.

unnamed Abelisauridae (Fanti, Cau, Martinelli and Contessi, 2014)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco
- (CMN 50446) tooth (~24x~11x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 912) tooth (~17x~10x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 913) tooth (~22x~12x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 914) partial tooth (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 915) tooth (~18x~8x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
(FSAC-KK-5015) (~2.7 m) axis (38 mm) (Smyth, Ibrahim, Kao and Martill, 2020)
?(FSAC-KK unnumbered) tooth (~16x~11x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
(MNHN MRS 348) tooth (48x17x13 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 783) tooth (28x14x6 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 1266) tooth (34x14x7 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 1838) tooth (36x19x9 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MSNM V6053) tooth (~23x~10x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
Comments- Fanti et al. (2014) list measurements of four "Abelisauridae indet." teeth housed in the MNHN which have MRS numbers corresponding to the Gara Sbaa locality (e.g. Rebbachisaurus type) of the Kem Kem beds.  Smyth et al. suggested the axis FSAC-KK-5015 represents an abelisaurid outside Majungasaurinae+Brachyrostra, perhaps a juvenile Rugops.  Ibrahim et al. (2020) figure CMN 50446 and MSNM V6053 as "?Abelisaurid tooth", and several others as "Indeterminate theropod teeth" which seem to be abelisaurid based on the low distal curvature in each, and marginal undulations in FSAC-KK 912 and 915.
References- Fanti, Cau, Martinelli and Contessi, 2014. Integrating palaeoecology and morphology in theropod diversity estimation: A case from the Aptian-Albian of Tunisia. Palaeogeography, Palaeoclimatology, Palaeoecology. 410, 39-57.
Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020. Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys. 928, 1-216.
Smyth, Ibrahim, Kao and Martill, 2020 (online 2019). Abelisauroid cervical vertebrae from the Cretaceous Kem Kem beds of southern Morocco and a review of Kem Kem abelisauroids. Cretaceous Research. 108, 104330.

Quseir abelisaurid left fibula in (F) lateral, (G, H) medial and (I, J) proximal views (after Salem et al., 2021). Scale = 20 mm.

unnamed probable abelisaurid (Sallam, O'Connor, Kora, Sertich, Seiffert, Faris, Ouda, El-Dawoudi, Saber and El-Sayed, 2016)
Middle Campanian, Late Cretaceous
Baris, El Hindaw Member, Quseir Formation, Kharga Oasis, Egypt
Material- (MUVP 187) proximal fibula (25x5 mm prox)
Comments- Discovered in 2008 or 2010, Sallam et al. (2016) initially reported "A proximal left fibula of a theropod dinosaur was also collected from the Baris area" and listed it as Theropoda indet..  Salem et al. (2021) noted the prominent m. iliofibularis tubercle is like abelisaurids and it has a "wide, slightly deep [proximomedial] fossa that closely resembles the condition in the abelisaurid Majungasaurus."  They say it "exhibits some affinities with abelisaurids" and refer to it as "Cf. Abelisaurid" in theit table 3. 
References- Sallam, O'Connor, Kora, Sertich, Seiffert, Faris, Ouda, El-Dawoudi, Saber and El-Sayed, 2016. Vertebrate paleontological exploration of the Upper Cretaceous succession in the Dakhla and Kharga Oases, Western Desert, Egypt. Journal of African Earth Sciences. 117, 223-234.
Salem, O'Connor, Gorscak, El-Sayed, Sertich, Seiffert and Sallam, 2021. Dinosaur remains from the Upper Cretaceous (Campanian) of the Western Desert, Egypt. Cretaceous Research. 123, 104783.

Elrhaz abelisaurid carina MNHN F.GDF-M30 in (E) labiolingual and (F) mesiodistal views (after Pochat-Cottilloux et al., 2022). Scale = 1 mm.

unnamed Abelisauridae (Pochat-Cottilloux, Allain and Lasseron, 2022)
Aptian, Early Cretaceous
GAD 5, Gadoufaoua, Elrhaz Formation, Niger
Material- (MNHN F.GDF-M30) two tooth fragments
(MNHN F.GDF-M37) two partial teeth
Comments- Collected in 1970, Pochat-Cottilloux et al. (2022) noted "some of this material was stored at the MNHN in a separate box" and had a "lighter color and a better quality of fossil preservation than other seen in other samples" which "suggested a different depositional environment to that of other samples so, as a result, this sample was separated from the rest" ... "as "site GADb"."  This is true for MNHN F.GDF-M30.  The authors state there are 3 serrations per mm on MNHN F.GDF-M30 and 4 per mm on MNHN F.GDF-M37, in the latter the carinae "extend along the entire length of both sides of the base" and in all specimens "the shape of the denticles and their number are typical of theropod teeth and could be assignable to Abelisauridae."
Reference- Pochat-Cottilloux, Allain and Lasseron, 2022. Microvertebrate fauna from Gadoufaoua (Niger, Aptian, Early Cretaceous). Comptes Rendus Palevol. 21(41), 901-926.

Galula abelisaurid tooth TNM 02088 in labial view (after O'Connor et al., 2006). Scale = 5 mm.

unnamed Abelisauridae (O'Connor, Gottfried, Stevens, Roberts, Ngasala, Kapilima and Chami, 2006)
Albian, Early Cretaceous
TZ-07, Namba Member of the Galula Formation, Tanzania

Material- (TNM 02088) lateral tooth (~19x~11.5x? mm)
(TNM coll.) eight lateral teeth, two anterior teeth
Comments- Discovered between 2002 and 2005, this material was described as theropod by O'Connor et al. (2006) and referred to the Unit I of the Red Sandstone Group at the time.  Roberts et al. (2010) subsequently revised the stratigraphic nomenclature, naming Unit I the Galula Formation.  Salem et al. (2021) refers the isolated teeth to Abelisauridae without comment, which seems likely given their stratigraphy, locality, size and morphology (particularly the nearly straight distal edge).  Several of the teeth were associated with the holotype of the titanosaur Shingopana, "suggesting a possible scavenging event."  Note the theropod caudals from the same locality described by O'Connor et al. differ from abelisaurids in their strong infradiapophyseal laminae and are here tentatively referred to Megaraptora.
Teeth have ~13-16 serrations per 5 mm mesially and distally.  O'Connor et al. further indicate "Two teeth are D-shaped in cross-section, indicating a position in the rostralmost portion of either the dentary or premaxilla."
References- O'Connor, Gottfried, Stevens, Roberts, Ngasala, Kapilima and Chami, 2006. A new vertebrate fauna from the Cretaceous Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania. Journal of African Earth Sciences. 44, 277-288.
Roberts, O'Connor, Stevens, Gottfried, Jinnah, Ngasala, Choh and Armstrong, 2010 (online 2009). Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa. Journal of African Earth Sciences. 57, 179-212.
Salem, O'Connor, Gorscak, El-Sayed, Sertich, Seiffert and Sallam, 2021. Dinosaur remains from the Upper Cretaceous (Campanian) of the Western Desert, Egypt. Cretaceous Research. 123, 104783.

Gokwe abelisaurid (left, right) and averostran (center) teeth (University of Zimbabwe coll.) (after Bond and Bromley, 1970).

undescribed Abelisauridae (Bond and Bromley, 1970)
Early Cretaceous
Gokwe Formation, Zimbabwe
- (University of Zimbabwe coll.) at least two teeth (~48x~31x?, ~49x~34x? mm)
Comments- Bond and Bromley (1970) were the first to figure three theropod teeth, discovered between 1962 and 1970, as their Plate 1A "Reptilian teeth of two types from the Gokwe Formation." Listed as being " in collection of Geology Department, University College of Rhodesia", the latter has since been renamed the University of Zimbabwe.  The first and third are clearly abelisaurid, with broad bases, straight to convex distal edges and fine serrations both mesially and distally (~6 per 5 mm on both carinae).  The second is narrower and more recurved, so referred to Averostra indet. here.
Reference- Bond and Bromley, 1970. Sediments with the remains of dinosaurs near Gokwe, Rhodesia. Palaeogeography, Palaeoclimatology, Palaeoecology. 8(4), 313-327.

Baharija abelisaurid tenth cervical vertebra MUVP 477 in (a) anterior, (b) posterior, (c) left lateral, (d) right lateral), (e) ventral and (f) dorsal views (after Salem et al., 2021).

unnamed possible brachyrostran (Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2021)
Early Cenomanian, Late Cretaceous
Gebel el Dist, Baharija Formation, Egypt
- (MUVP 477) (~5.8 m) tenth cervical vertebra (67.00 mm)
Comments- Discovered in 2016, Salem et al. (2021) added this to Tortosa et al.'s ceratosaur matrix and recovered it as an abelisaurid based on "(1) long axis of diapophysis forms angle of 65° to midsagittal plane; (2) dorsal surface of neural arch clearly delimited from lateral surface of diapophysis; (3) deep spinoprezygapophyseal and spinopostzygapophyseal fossae; and (4) well-developed epipophyses, comparable to those observed in the tenth cervicals of Majungasaurus and MPM 99 (but smaller than those of Carnotaurus and Ekrixinatosaurus novasi)."  The resulting Salem et al. (2022) publication officially describing the specimen did not use character 1.  While it was a brachyrostran (in a polytomy with Ekrixinatosaurus, Ilokelesia and the derived clade) in majority rule trees, a posteriori pruning of taxa was not done to determine if this is real signal or merely an artifact.  Examination of the 2022 supplementary data should resolve this.
References- Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2021. First definitive record of Abelisauridae from the Bahariya Formation, Bahariya Oasis, Western Desert of Egypt increases diversity of large-bodied theropods in the MIddle Cretaceous of northeastern Africa. The Society of Vertebrate Paleontology Virtual Meeting Conference Program, 81st Annual Meeting. 225-226.
Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2022. First definitive record of Abelisauridae (Theropoda: Ceratosauria) from the Cretaceous Bahariya Formation, Bahariya Oasis, Western Desert of Egypt. Royal Society Open Science. 9: 220106.

Additionally, a review paper isn't really the place for new information or unpublished sources, so here are some extensive updates to poorly documented finds-

"Sidormimus" Molina-Perez and Larramendi, 2019
= "Dogosaurus" Anonymous, 2000 online
Aptian-Albian, Early Cretaceous
Gadoufaoua, Elrhaz Formation, Niger

Material- (MNN GAD coll.) (~1 m) partial skeleton including maxilla, cervical ribs, dorsal vertebrae, dorsal ribs, uncinate processes, sacral vertebrae, scapula, coracoid, sternal plates, sternal ribs, humerus, radius, ulna, carpus, manus including manual digit II, phalanges, manual unguals and manual claw sheath, pelvis including pubis and hindlimb including femur, tibia, fibula, calcaneum, metatarsus, pedal digit II, pedal digit III, pedal digit IV and pedal unguals
Comments- This specimen was discovered on September 13 2000 and announced by Lyon (2000 online) as "a brand new, dog-sized theropod, which the team has affectionately (but unofficially) named "Sidormimus."" and a "new, dog-sized carnivore - perhaps one of the smallest dinosaurs ever", with a photo of the specimen in situ.  The same photo was labeled Dogosaurus on a dispatch from Project Exploration on the National Geographic website, which also stated it was "no more than three feet long. Its slender neck and ribcage were preserved poking out of the rock. Its long, clawed hind leg was uncovered as we dug around the exposed bones." Sereno et al. (2004) first announced the specimen in print, as "a small (1 m) articulated skeleton showing many abelisauroid and noasaurid synapomorphies, including pneumatized presacral and sacral neural arches, proportionately long presacral centra, and others" and "preserves a maxilla and pelvic girdle, the former of which bears the distinctive abelisaurid pit-and-groove texturing of the skull bones."  They include it in their cladogram as "Gadoufaoua noasaurid", but it is not an OTU in the matrix.  It is also listed in Sereno and Brusatte (2008) as "undescribed noasaurid" in a faunal list, and is noted to have a pubic boot more with limited expansion than the "Kryptops" postcrania MNN GAD1-2. Sidor (pers. comm. 2005) confirms the "Sidormimus" specimen is the Elrhaz noasaurid. Sereno (2010) devoted an SVP abstract to it, noting the specimen has- long and robust posterior cervical ribs, dorsal centra more than twice as long as tall, five uncinate processes (unique among non-maniraptoran theropods), posteriorly directed glenoid, enlarged coracoid, ossified sternal plates and ribs, forelimb 18% of hindlimb length, robust deltopectoral crest and olecranon process, manual digit II longer than III, straight manual unguals, tibia longer than femur, pedal digits II and IV much shorter than III, and short flat pedal unguals.  Sereno (2017) provided further information- straight tibia, weak iliofibularis tubercle on fibula, fibula distally fused with calcaneum, no dorsal vascular groove on pedal unguals.  The co-occuring Afromimus shared fibular-calcaneum fusion but differs in the other characters, in addition to having a more robust proximal fibula and distal fibula which is expanded transversely.  Molina-Perez and Larramendi (2019) first used the name in print, specified to be a nomen nudum.
References- Lyon, online 2000.
Anonymous, online 2000.
Sereno, Wilson and Conrad, 2004. New dinosaurs link southern landmasses in the Mid-Cretaceous. Proceedings of the Royal Society, Series B. 271, 1325-1330.
Sereno and Brusatte, 2008. Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger. Acta Palaeontologica Polonica. 53(1), 15-46.
Keillor, Sereno and Masek, 2010. Range of movement in a noasaurid forelimb: In situ data and joint reconstruction. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 114A.
Sereno, 2010. Noasaurid (Theropoda: Abelisauroidea) skeleton from Africa shows derived skeletal proportions and function. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 162A.
Sereno, 2017. Early Cretaceous ornithomimosaurs (Dinosauria: Coelurosauria) from Africa. Ameghiniana. 54, 576-616.
Molina-Perez and Larramendi, 2019. Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes. Princeton University Press. 288 pp.

"Titanovenator" Boyd, 2020 online
"T. kenyaensis" Boyd, 2020 online
Maastrichtian, Late Cretaceous
Lapurr sandstone (= Turkana Grits), Turkana, Kenya
- (KNM-WT coll.) (~11-12 m) multiple specimens including cranial material (including a partial skull - premaxilla, postorbital and braincase), axial material and appendicular material (including astragalocalcaneum)
Comments- Discovered in 2004, this is based on unassociated material referred to one taxon "based on morphological consistency and on the recovery of specimens from a narrow stratigraphic and geographic area."  Abelisaurid characters listed by Sertich et al. (2013) include- "a tall, rugose premaxilla, an anteroventrally inclined posterior border of the postorbital," ... "a prominent dorsal projection of the parietals and supraoccipital" and an "ascending process [that] is low and subrectangular, separated from the anterior surface of the astragalus by a distinct fossa."  They further note the "skull is strongly coossified, with a thickened but weakly sculptured skull roof", "no prominent cranial ornamentation is evident" and "the astragalocalcaneum is completely coossified and displays a prominent transverse sulcus on the anteroventral surface."  The museum collection is based on an azhdarchid vertebra found by the same team from the same locality (O'Connor et al., 2011).
Boyd (2020) included the name Titanovenator kenyaensis in the pdf visual portion of her "Ask a Geologist" presentation for RUGM.  It accompanies a photo of the MCN Carnotaurus cast that is also labeled Abelisauridae gen. et sp. nov., and based on the name refers to Sertich et al.'s (2013) giant Kenyan abelisaurid taxon.  It is a nomen nudum as the pdf was not "issued for the purpose of providing a public and permanent scientific record" (ICZN Article 8.1.1) and doesn't "state the date of publication in the work itself" (Article 8.5.2), while the name itself was not "registered in the Official Register of Zoological Nomenclature (ZooBank)" (Article 8.5.3) or "accompanied by a description or definition that states in words characters that are purported to differentiate the taxon" (Article 13.1.1).  The name (as "Titanovenator kenyanis") actually predates Boyd's presentation, originating on a Jurassic Park message board from 2013 in a post under the pseudonym Rex Fan 684, but this is not considered a source for catalogued nomina nuda here.
References- Sertich, Manthi, Sampson, Loewen and Getty, 2006. Rift Valley dinosaurs: A new Late Cretaceous vertebrate fauna from Kenya. Journal of Vertebrate Paleontology. 26(3), 124A.
O'Connor, Sertich and Manthi, 2011. A pterodactyloid pterosaur from the Upper Cretaceous Lapurr sandstone, west Turkana, Kenya. Anais da Academia Brasileira de Ciências. 83(1), 309-315.
McCoy, 2013 online.
Sertich, Seiffert and Manthi, 2013. A giant abelisaurid theropod from the Latest Cretaceous of northern Turkana, Kenya. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 211.
Boyd, 2020 online. Ask a Geologist: Geology & Paleontology of Kenya. Rutgers Geology Museum. 25 pp.

Duwi abelisaurid teeth (MGUP coll.; lost) in (left) labiolingual and (right) basal view (after Gemmellaro, 1921).

unnamed Abelisauridae (Di Stefano, 1919)
Late Campanian, Late Cretaceous
Duwi Formation, Al Sharauna, Egypt

Material- (MGUP MEGA002; lost?) tooth (16.63x13.01x6.69 mm) (described by Smith and Lamanna, 2006)
Late Campanian, Late Cretaceous
Duwi Formation, Al Sharauna, Gebel Duwi and/or Gebel Nakheil, Egypt

(MGUP MEGA001) partial lateral tooth (?x~22.7x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP MEGA002 B) lateral tooth (~35.2x~25x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP MEGA003) partial lateral tooth (?x~30x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP coll.; lost) more than two lateral teeth
Comments- Gemmellaro (1921) referred several remains to Megalosaurus crenatissimus, from three localities in eastern Egypt.  The phosphate layers of Gebel Duwi are the Late Campanian Duwi Formation (e.g. Salama et al., 2021).  Similarly, "Phosphate mines at Kosseir-el-Khadim, Gebel Nakheil, near Kosseir [now Quseer], on the Red Sea" are also the Duwi Formation (Valentine, 1985).  The third locality has been mistaken in every subsequent reference as "Sciarauna-el-Ghibli, presse Sibaiya (Valle del Nilo)", but the 'c' is actually a poorly photocopied 'e', as indicated by Di Stefano's (1919) original publication of the expedition which states "The richest and most extensive deposit is the one found on the hill of Seiarauna, on which are the two villages called Seiarauna-el-Bahri, i.e. Seiarauna at the river, and Seiarauna-el-Ghibli, i.e. upstream" (translated). The latter is now known as Ash Sharawinah al Qibliyah, El-Sharâwna el-Qiblîya or simply Al Sharauna among other variants, and is indeed directly across the Nile from Sebaiya (also called As Sibaiyyah and Al Sebaaia West City).  Smith and Lamanna (2005) stated the particular tooth they described was from "near Idfu in the Nile Valley of Egypt (Fig. 1, exact locality data are unknown; research in Palermo did not reveal a more accurate location)", but Idfu (also called Edfu) is 30 km to the southeast.  Gemmellaro states "the majority of the specimens came from [Seiarauna-el-Ghibli]. But a careful research recently conducted by myself on the abundant material donated by Cortese has allowed me to find all the types studied also in the locations of Gebel Nakheil (Kosseir-el-Khadim and Uadi-el-Anz mines) and of Gebel Duwi" (translated), suggesting no other localities were involved and perhaps 30 km was considered "near" by whoevever wrote that record.
Di Stefano (1919) first reported theropod material from Al Sharauna, collected by him in 1912 and also donated to the MGUP by Cortese between then and his publication- "In contact between the phosphates and the alternating marls, bones and quite a few dinosaurian teeth (Mosasaurus, Platecarpus, Megalosaurus, etc.) are found, which will be the subject of a special study."  That study was Gemmellaro (1921), who as noted above also discovered theropod material in the Gebel Duwi and Gebel Nakheil collections.  Unfortunately, Gemmellaro never specifies which of the three localities any of his discussed specimens is from, nor does he state how many teeth were in the MGUP collections.  Three teeth are figured, with those in figures 12 and 13 typically abelisaurid with low crowns serrated to the base both mesially and distally.  Curvature and crown height ratios are most similar to posterior dentary teeth of Majungasaurus.  Gemmellaro compares the teeth favorably to Majungasaurus syntypes FSL 92.306a and b and a Maevarano tooth figured by Thevenin 1906 (MNHN coll.).  A smaller, third tooth is illustrated as figure 14, said to be among "some which, although sharing some common features, differ in the shape of the crown which is not backward curved but is almost isosceles with the sides having a profile slightly convex or straight."  While Gemmellaro believed "such differences in shape and in dimensions between teeth has to be attributed to the diverse locations they occupied in the jaws, and also to the different age of the individuals whom the teeth belonged to", the mesiodistally narrower crown suggests another taxon such as a noasaurid, and that tooth is listed as Averostra indet. here.  Gemmellaro described two unguals and figured one.  While he compares them favorably to crenatissimus syntype FSL 92.290, the preserved section of the figured specimen is less tapered in side view with no obvious vascular groove, and this holds true as well for other Majungasaurus pedal unguals (e.g. FMNH PR 2434, MSNM V6418, V6419) as well as Masiakasaurus (e.g. FMNH PR 2135) and indeed most theropods.  Photos provided by Di Patti (pers. comm. 6-2023) show the figured element (MGUP MEGA004) is a sauropod pedal ungual while the other (MGUP MEGA005) compares well to an ankylopollexian manual ungual I.  They are referred to Titanosauria indet. and Hadrosauroidea indet. here based on age.
Smith and Lamanna (2006) described one of Gemmellaro's teeth in detail (MGUP MEGA002), although it is not one previously figured.  They identified it as abelisaurid based on "the distal curvature profile exhibits almost no curvature and is tilted slightly toward the apex in lateral view" (but this is not true of Gemmellaro's Figure 12), and as closer to Majungasaurus and Lameta AMNH 1753/1955 than Rugops, Rugops? sp. UCPC 10 or Bajo Barreal UNPSJB-PV 247 based on "mesial curvature profile begins at a strong curve at about 1/3 the crown height basal to the apex (but this is not true of Gemmellaro's Figure 12) and "the ... interdenticular sulci complex forms an intermediate condition between being absent and well developed" (unknown in Gemmellaro's figured specimens).  They find "The discriminant analysis (DA) correctly identified 96.6% of the teeth in the sample and classified MGUP MEGA002 as Majungasaurus" but note "the assignment of the Egyptian tooth to the genus Majungasaurus in particular is unlikely given that Africa and Madagascar were separated by the Mozambique Channel throughout the Cretaceous", and indeed the relatively low sample of abelisaurid teeth tested makes this questionable.  In fact he combination of stout shape plus concave basal distal edge with a convex apical distal edge is unlike figured Majungasaurus teeth.
Interestingly, the MGUP only has three teeth in their collection now (Di Patti, pers. comm. 6-2023), none of which are MGUP MEGA002 or match the three illustrated by Gemmellaro.  One (MGUP MEGA002 B) is abelisaurid based on the slightly convex distoapical edge, although the mesial edge is similar to Gemmellaro's Figure 12 instead of curving abruptly at a third of its height.  Marginal undulations are present as in some other abelisaurids (Abelisaurus, Chenanisaurus, Majungasaurus, Skorpiovenator).  There are ~10 mesial serrations per 5 mm and ~11 distal serrations.  The other two teeth (MGUP MEGA001 and MGUP MEGA003) are more partially preserved but of similar size and serration density (~10 distal serrations per 5 mm in MEGA001; ~10.5 mesial serrations per 5 mm in  MEGA003), and each shows marginal undulations as well, so they are tentatively placed as Abelisauridae here.  There are no precise locality data for any of them past Maastrichtian of Egypt.
References- Di Stefano, 1919. Osservazioni sul Cretaceo e sull'Eocene del Deserto Arabico di el-Sibaiya, nella valle del Nilo. Bollettino del R. Comitato Geologico d'Italia. Serie V(47), 1-39.
Gemmellaro, 1921. Rettili maëstrichtiani di Egitto. Giornale di Scienze Naturali ed Economiche. 32, 339-351.
Valentine, 1985. Structure and tectonics of the southern Gebel Duwi area, Eastern Desert of Egypt. Department of Geology and Geography, University of Massachusetts. Contribution No. 53, 141 pp.
Smith and Lamanna, 2006. An abelisaurid from the Late Cretaceous of Egypt: Implications for theropod biogeography. Naturwissenschaften. 93(5), 242-245.
Salama, Altoom, a Allam, Ajarem and Abd-Elhameed, 2021. Late Cretaceous anacoracid sharks (Squalicorax) from Duwi Formation, Gebel Duwi, central Eastern Desert, Egypt: Qualitative and quantitative analyses. Historical Biology. 33(11), 3056-3064.

Reference- de Souza-Júnior, Candeiro, da Silva Vidal, Brusatte and Mortimer, 2023. Abelisauroidea (Theropoda, Dinosauria) from Africa: A review of the fossil record. Papéis Avulsos de Zoologia. 63, e202363019.