In the comments to my last post describing Cau's (2018) new paper detailing the acquisition of characters on the line to Aves, reader AOF requested a post similar to
what I did six years ago with the Carrano et al. (2012) tetanurine analysis. Namely, testing alternative topologies using constraint analyses to see how many more steps they would require. I think these kinds of things can be illuminating. I've often said that we shouldn't think of a new cladogram as just 'the best new hypothesis', but rather check individual components of the tree to see how likely or unlikely they are to be correct. Cau's 2018 matrix has a reduced taxon sample, which could easily change the number of steps compared to a complete sample. On the other hand, I think Andrea tries to include all proposed characters in his MegaMatrix, which could make this a more honest measure of comparative topology length than most studies. I'm not sure which variable overrides the other. Then we have score correctness, which I've never checked in a Cau matrix, so I'm taking that at face value.
Andrea sent me his NEXUS file, but whereas the paper reports 3072 MPTs of 6790 steps, I found 10872 MPTs of that length.
Eoraptor and
Buriolestes aren't always sauropodomorphs,
Pisanosaurus is sometimes an ornithischian,
Asilisaurus,
Silesaurus and
Sacisaurus are an unresolved trichotomy, Enantiornithes can be paraphyletic with
Zhongjianornis among them, and
Fake Ornithuromorpha is less resolved, as
Patagopteryx and
Apsaravis can be outside
Hongshanornis+Aves,
Archaeornithura can be a songlingornithid, etc.. I think Andrea's philosophy would be that these things vary with taxon inclusion, so aren't a definite part of his data. The absence of any included spinosaurids, carcharodontosaurines, parvicursorines or
Avimimus unfortunately makes some weird 80s and 90s hypotheses untestable. After six more years of experience, I've added a new category "less likely" because I think that factors like scoring accuracy and taxon inclusion can have a larger influence. As I said in the 2012 post,
the corrected TWG matrix needed 15 more steps to get a monophyletic Deinonychosauria which is the most common outcome for TWG matrices today. I'll say the Lori matrix recovers at least one hypothesis found to be "unlikely" here, so even that's not the kiss of death.
Basically ambiguous
0 steps- Maniraptoromorph
Compsognathus.
0 steps- Megaraptoran
Gualicho.
1 step-
Ceratosaurus closer to abelisauroids than
Elaphrosaurus.
1 step- Megalosauroid piatnitzkysaurids.
1 step- Coelurosaurian
Zuolong. Ends up as a basal maniraptoromorph between
Coelurus and
Ornitholestes.
1 step- Coelurid
Aorun, as in its original description. It moves to Maniraptoromorpha with
Coelurus.
1 step- Coelurid
Tanycolagreus, as in its original description.
Coelurus moves into Tyrannosauroidea with
Tanycolagreus.
1 step- Compsognathid
Sinosauropteryx and/or
Sinocalliopteryx.
1 step- Tyrannosauroid
Sinocalliopteryx or
Coelurus.
1 step- Anchiornithid or archaeopterygid
Xiaotingia.
1 step- Scansoriopterygids closer to Aves than
Archaeopteryx.
1 step-
Sapeornis closer to Aves than
Confuciusornis.
1 step-
Zhongjianornis sister to Pygostylia, as in its original description.
1 step-
Ichthyornis closer to Aves than
Hesperornis, the consensus until the recent cranial redescription of
Ichthyornis.
2 steps- Theropodan
Eodromaeus.
2 steps-
Chilesaurus just outside Avepoda,
which was my best guess back in 2015 considering the results of its original misscored matrices and my subjective feelings of what would plausibly reverse.
2 steps- Ceratosaurian
Gualicho. It has an uncertain placement within the clade, though is excluded from Abelisauria.
2 steps- Megaraptora as coelurosaurs just outside of Tyrannoraptora.
This was my result back in 2010 after adding Benson's Neovenatoridae data to my theropod supermatrix (since superseded by the Lori analysis).
Bicentenaria is at this level too, while
Guanlong and
Tanycolagreus become maniraptoromorphs.
2 steps- Maniraptoran
Ornitholestes.
2 steps- Hongshanornithid
Parahongshanornis, as in its original description.
 |
| Cast YPM 56693 of the Mononykus olecranus holotype pes in plantar view, courtesy of Senter. |
Quite likely to be true
3 steps- Saurischia. Herrerasaurs and
Eodromaeus are theropods. Note that while some of these constraints were tested in the Ornithoscelida paper, the studies differ in both taxonomic content and characters used, so that MegaMatrix results don't necessarily correlate with Ornithoscelida paper results and should not be seen as scooping anything we find.
3 steps- Ornithischian
Daemonosaurus.
Chilesaurus is sister to Averostra.
3 steps- Theropodan
Herrerasaurus/
Tawa/
Daemonosaurus. These each take three steps more, and other herrerasaurs follow when one is constrained.
3 steps- Dilophosaurid
Liliensternus, as in Paul (1988).
3 steps- Ceratosauria sensu lato, combining Neoceratosauria and Coelophysoidea.
Chilesaurus is the most basal theropod,
Elaphrosaurus plus
Limusaurus are the basal neoceratosaurs, and
Gualicho is the most basal tetanurine.
3 steps-
Eustreptospondylus and/or Megalosaurus outside Avetheropoda. If one is constrained, the other follows.
3 steps- Megaraptoran
Eotyrannus, as in Novas et al. (2013).
3 steps- Maniraptoran
Coelurus.
3 steps- Troodontid
Aurornis,
Anchiornis and/or
Xiaotingia.
3 steps-
Chongmingia sister to Ornithothoraces, as in p2 of its original description.
4 steps- Ornithischian silesaurids.
Lewisuchus is outside Dinosauria, Saurischia exists, and
Asilisaurus and
Pisanosaurus form a silesaur grade to either side of Silesauridae.
4 steps- Phytodinosauria.
Eoraptor and
Buriolestes are sister to Dinosauria, while herrerasaurs and
Eodromaeus are theropods.
4 steps- Ornithischian
Chilesaurus. Ornithoscelida occurs.
4 steps- Theropodan
Eoraptor.
Buriolestes, herrerasaurs and
Eodromaeus also theropods.
4 steps- Abelisaurid
Eoabelisaurus, as in its original description.
4 steps- Metriacanthosaurids outside Allosauria (
Allosaurus plus
Carcharodontosaurus).
Acrocanthosaurus joins
Neovenator, so this also covers carcharodontosaurid
Neovenator.
4 steps- Tyrannosauroid
Compsognathus, as in Olshevsky (1991). Surprised this one is so parsimonious. A Compsognathidae with
Aorun,
Bicentenaria and
Sinosauropteryx are the basalmost tyrannosauroids, with
Sinocalliopteryx, Coeluridae including
Tanycolagreus and
Guanlong successively closer to core tyrannosauroids.
4 steps- Maniraptoromorph
Tanycolagreus and/or
Guanlong.
4 steps- Ornithomimosaurian
Gualicho. Tested due to Rauhut (2003) finding the very similar
Deltadromeus in this position. Note that ornithomimosaurian
Elaphrosaurus is 36 steps longer, so the cases aren't that similar.
4 steps- Therizinosaurian
Jianchangosaurus. Still outside
Falcarius plus
Beipiaosaurus, and Cau said in a comment to the last post
Jianchangosaurus was still an alvarezsauroid even after adding
Erlikosaurus and
Shuvuuia. I'm not revealing much by saying the Lori analysis finds
Jianchangosaurus to be a therizinosaur between
Falcarius and
Beipiaosaurus as in its original description. Seems fishy...
4 steps- Archaeopterygid
Jinfengopteryx, as in its original description.
4 steps- Archaeopterygid
Anchiornis.
4 steps- Oviraptorosaurian scansoriopterygids. They have an uncertain position within the clade, and therizinosaurs are still sister to oviraptorosaurs.
 |
| Allosaurus fragilis holotype tooth (YPM 1930) in ?lingual view. Courtesy of the YPM. |
5 steps-
Dilophosaurus/
Cryolophosaurus closer to Averostra than
Coelophysis.
5 steps- Non-avetheropod
Compsognathus, as in Novas (1992). Very surprised this is so easy to get. It's even more extreme than Novas' version, where
Compsognathus was at least closer to avetheropods (his Tetanurae) than
Piatnitzkysaurus and
Eustreptospondylus, because in the constrained trees Carnosauria still has the same content as Cau's MPTs.
Sinosauropteryx joins it.
5 steps- Maniraptoromorph
Eotyrannus. I'm surprised by this, since I figured the result in other matrices was due to a lack of tyrannosauroid characters, which I think are all in the MegaMatrix.
5 steps- Non-tyrannoraptoran
Coelurus, as in Paul (1988).
5 steps- Avemetatarsalian alvarezsauroids, as in Sereno (1999).
Jianchangosaurus is still a basal alvarezsauroid.
5 steps-
Haplocheirus compsognathid/coelurid grade, as in Alifanov and Saveliev (2011). Wasn't there some analysis that recovered it here too? I just constrained it to be outside Maniraptoriformes (including alvarezsaurids).
5 steps- Non-pennaraptoran therizinosaurs, which fall out sister to Pennaraptora like the current consensus.
5 steps-
Chongmingia a basal ornithurine (sensu Gauthier) outside
Shenzhouraptor and Pygostylia, as in p1 of its original description. The Lori analysis recovers it in a different position than p1, p2 or Cau's analysis.
Less likely
6 steps- Non-eusaurischian saurischian
Eoraptor.
Buriolestes follows, but herrerasaurs and
Eodromaeus are theropods.
6 steps- Theropodan
Guaibasaurus. Non-dinosaurian
Eoraptor and
Buriolestes, and this recovers Phytodinosauria.
6 steps-
Eustreptospondylus closer to Neotetanurae than
Megalosaurus, as in Holtz (2000). I'm actually surprised this is so unlikely.
6 steps- Carnosaurian
Sinosauropteryx, as in Longrich (2002). Though Longrich's phylogeny was a bit different in having megalosaurids and metriacanthosaurids outside Avetheropoda.
6 steps- Ornithomimosaurian
Haplocheirus, as in the Bayesian analyses of Cau and Lee and Worthy (2011).
6 steps- Arctometatarsalian therizinosaurs, as in Sereno (1999).
6 steps-
Shenzhouraptor closer to Aves than
Sapeornis.
7 steps- Sauropodomorph
Staurikosaurus but not
Herrerasaurus, as in pachypodosaur
Staurikosaurus of Kischlat (2000).
7 steps- Megalosauroid
Monolophosaurus. Megalosauroidea remains in Carnosauria.
7 steps- Coelurosaurian
Neovenator. Not sure if this has been suggested in print before, but I noticed quite a few coelurosaur-like characters when scoring
Neovenator for the Lori matrix. It forms the most basal coelurosaur clade with
Aorun and
Gualicho.
7 steps- Maniraptoran
Compsognathus.
7 steps- Paravian alvarezsaurids, though note the lack of parvicursorines probably affects these numbers. They (including
Jianchangosaurus and
Haplocheirus) emerge as the most basal paravians.
7 steps- Basal paravian
Anchiornis,
Aurornis, scansoriopterygids,
Serikornis and/or
Xiaotingia.
7 steps- Archaeopterygid
Rahonavis, as in Forster et al. (1998).
7 steps- Fake-Ornithuromorphan
Confuciusornis, as in Kurochkin (2006). I really thought this would be more difficult to achieve than enantiornithine
Confuciusornis (below).
 |
| Box of Archaeornithimimus asiaticus elements from AMNH 6576, with my identifications (dc- distal caudal, dt- distal tarsal, pedal except m 1-1 and m 3-2). Is that a proximal metatarsal I in the upper left? Courtesy of the AMNH. |
8 steps- Non-eusaurischian saurischian
Herrerasaurus.
Eodromaeus and sometimes
Eoraptor become herrerasaurs and
Buriolestes is one node more stemward.
8 steps- Tetanurine
Cryolophosaurus, as in Carrano et al. (2002).
Dilophosaurus stays in Coelophysoidea.
8 steps- Ceratosaurian megalosaurids, as in Britt (1991).
Chilesaurus
falls out in a polytomy with megalosaurids and other ceratosaurs.
8 steps- Megalosauroid piatnitzkysaurids, with Megalosauroidea outside Avetheropoda. Since this is the Carrano et al. consensus, I thought it would take less steps.
8 steps-
Monolophosaurus sister to Avetheropoda, as in Smith et al. (2007). Megalosaurids and piatnitzkysaurids fall out as more basal tetanurines.
8 steps- Arctometatarsalian tyrannosauroids, AKA
Tyrannosaurus closer to
Ornithomimus than to birds as in Holtz (1994). I'm very surprised this is so parsimonious.
Coelurus and
Bicentenaria join Tyrannosauroidea, but
Gualicho leaves to be a ceratosaur.
8 steps- Maniraptoran tyrannosauroids, as in Sereno (1999). This is accomplished more by moving ornithomimosaurs (including
Gualicho) stemward to be the most basal coelurosaurs except for
Zuolong.
Somewhat possible
9 steps- Classic late 80s to early 90s topology where
Staurikosaurus is sister to
Herrerasaurus plus Dinosauria.
Tawa plus
Daemonosaurus are closer to dinosaurs than both, while
Sanjuansaurus follows
Herrerasaurus.
9 steps-
Piatnitzkysaurus outside Orionides, as in Rauhut (2003).
Condorraptor follows
Piatnitzkysaurus, and megalosauroids fall outside Avetheropoda. Surprised this is so high.
9 steps- Carnosaurian
Tyrannosaurus, which brings megaraptorans,
Gualicho and
Bicentenaria to form the sister group of Allosauroidea (including
Monolophosaurus). I bet this is more parsimonious than most readers would assume given published topologies over the past two decades.
9 steps- Avialan
Caudipteryx, as in its original description. The rest of Oviraptorosauria follows it, though troodontids are still closer to Aves.
9 steps- Avialan
Microraptor, as in Agnolin and Novas (2013). Weirdly becomes the most basal troodontid, with that family closer to Aves than scansoriopterygids and anchiornithids.
9 steps- Avialan
Unenlagia, as in its original description and Agnolin and Novas (2013). Halszkaraptorines are unenlagiids, which are outside the Troodontidae plus Ornithes clade.
9 steps- Deinonychosauria. Scansoriopterygids are oviraptorosaurs, while
Jinfengopteryx and anchiornithids are avialans.
9 steps- Archaeopterygidae sister to Troodontidae. Anchiornithines fall out as archaeopterygids.
10 steps-
Monolophosaurus outside Orionides, as in Carrano et al.
(2002). Megalosaurids and piatnitzkysaurids form successively closer
outgroups to Avetheropoda.
10 steps-
Fukuivenator excluded from Alvarezsauridae plus Therizinosauria plus Pennaraptora as in its original description. It emerges as the sister to other maniraptorans.
10 steps- Eumaniraptora excluding troodontids as in Agnolin and Novas (2013). Scansoriopterygids are oviraptorosaurs.
10 steps- Dromaeosaurid
Xiaotingia, as in Senter et al. (2012). Falls out in Microraptoria.
10 steps- Dromaeosaurid
Balaur, as in its original description. Falls out sister to Unenalagiinae plus Halszkaraptorinae.
11 steps- Tyrannosauroid
Acrocanthosaurus, as in Bakker et al. (1988). Tyrannosauroids become carnosaurs, with
Sinraptor,
Acrocanthosaurus and
Bicentenaria successively closer to the 'core tyrannosauroid' clade of
Eotyrannus,
Gualicho, megaraptorans and
Tyrannosaurus.
Tanycolagreus and
Guanlong are now maniraptoromorphs.
11 steps- Alvarezsauroid
Nqwebasaurus. Alvarezsauroids emerge sister to ornithomimosaurs, with
Haplocheirus and
Jianchangosaurus forming a basal
[edit] arctometatarsalian clade.
11 steps-
Mahakala outside Unenlagiinae plus Eudromaeosauria (
Halszkaraptor follows), as in most TWG matrices (though Senter et al. 2012 recovered it sister to unenlagiines like Cau).
Unlikely
12 steps- Alvarezsauroid
Chilesaurus,
where it emerged in the Lori matrix back in 2015.
12 steps- Ornithuran (sensu Gauthier) oviraptorosaurs, as in Maryanska et al. (2002). Constraining
Khaan to be closer to
Meleagris than
Archaeopteryx results in oviraptorosaurs (including scansoriopterygids) being the first clade to diverge from the avian stem after
Archaeopteryx.
12 steps- Basal paravian
Jinfengopteryx, as in Foth et al. (2014).
13 steps- Coelophysoid
Elaphrosaurus, as in Paul (1988). Ceratosauria sensu lato forms,
Elaphrosaurus is outside core coelophysoids and
Limusaurus and sometimes
Gualicho follow.
13 steps- Compsognathid
Nqwebasaurus, as in Novas et al. (2013). Compsognathids (including
Aorun) become ornithomimosaurs.
13 steps- Dromaeosaurid
Rahonavis. Emerges in the unenalgiine plus halszkaraptorine clade.
14 steps- Neovenatorid megaraptorans, though this actually moves
Neovenator out of Carnosauria into Tyrannosauroidea, so isn't that similar to Benson's topology.
14 steps- Enantiornithine
Confuciusornis.
15 steps- Sauropodomorphan
Chilesaurus, where it emerges as the most basal member.
15 steps- Carnosaurian
Ceratosaurus, as in Currie (1995). Other ceratosaurs follow.
15 steps- Alvarezsaurids closer to Aves than dromaeosaurids or troodontids.
Haplocheirus and
Jianchangosaurus remain behind as ornithomimosaurs. Note the lack of parvicursorines probably affects this number.
15 steps- Archaeopterygid
Unenlagia, as in Forster et al. (1998).
Buitreraptor remains in Dromaeosauridae.
 |
| Cladogram of archosauromorphs after Kischlat (2000). Note saurischian Marasuchus and sauropodomorph Staurikosaurus. |
16 steps- Saurischian
Marasuchus, as in Kischlat (2000). Ornithischian silesaurs result, and
Lewisuchus sister to
Eodromaeus plus avepods.
16 steps- Non-avetheropod
Sinraptor as in Longrich (2002). Carnosauria
becomes a grade,
Acrocanthosaurus joins
Neovenator, and
Guanlong and
Tanycolagreus become maniraptoromorphs.
18 steps- Basal paravian
Archaeopteryx. Deinonychosauria forms, and anchiornithids and scansoriopterygids are further from Eumaniraptora.
19 steps- Coelophysoid ornithischians or ornithischians sister to Neotheropoda, as in Baron (2017).
Chilesaurus is the most basal theropod.
19 steps- Basal deinonychosaur
Archaeopteryx, as in Xu et al. (2011).
Anchiornis,
Aurornis and
Serikornis are one node closer to Dromaeosauridae plus Troodontidae.
20 steps-
Monolophosaurus sister to
Guanlong, as in Carr (2006) who proposed they were an adult and juvenile of the same species. The pairing resolves as sister to Tyrannoraptora.
21 steps- Carnosaurian megaraptorans. Er, wow. The Carrano et al. consensus is blown out of the water. They don't even group with
Neovenator, instead (including
Gualicho and
Bicentenaria) being in a trichotomy with megalosaurids and an Allosauroidea including piatnitzkysaurids.
I'm drawing the line here for plausibility
22 steps- Theropodan
Marasuchus, as in Olshevsky (1991). Silesaurids,
Eoraptor+
Buriolestes and herrerasaurians are also theropods.
23 steps- Avialan therizinosaurs, as in Maryanska et al. (2002). One of the odder parts of the classic 'oviraptorosaurs are birds' analysis is that they recovered therizinosaurs as closer to birds than dromaeosaurids or troodontids, which was only briefly mentioned in the text, while they removed Troodontidae and Therizinosauria from their figured cladogram. Constraining this result leads to oviraptorosaurs being dragged along, and the whole of Caenagnathiformes is sister to taxa closer to Aves like scansoriopterygids, anchiornithids,
Archaeopteryx, etc..
24 steps- 'Allosaur'
Ornitholestes, as in Paul (1988). Although Paul includes
Ornitholestes in his Allosauridae, he views that family as paraphyletic to tyrannosaurids and his figure 10-1 shows
Allosaurus closer to tyrannosaurids than
Ornitholestes. I thus only specified
Ornitholestes to be closer to
Allosaurus than megalosaurids, piatnitzkysaurids,
Compsognathus and birds. The resulting tree has ornitholestiids (including
Zuolong) sister to core allosauroids including
Monolophosaurus (which was considered closer to
Allosaurus by Paul too- pg. 307), but tyrannosauroids and compsognathids are coelurosaurs.
24 steps- Ornithuran (sensu Gauthier) alvarezsaurids. The most crownward alvarezsaurids were ever proposed to be, closer to Aves than
Archaeopteryx. They end up just crownward of anchiornithids, and weirdly form a clade there with scansoriopterygids and oviraptorosaurs. As usual, the absence of parvicursorines probably affects the numbers.
24 steps- Archaeopterygid
Protarchaeopteryx, as in Paul (2002).
Xiaotingia and scansoriopterygids are also closer to
Archaeopteryx than Aves in these trees.
25 steps- Tyrannosauroids sister to Pennaraptora, as in Sereno (1999). Like Sereno's trees, alvarezsauroids and therizinosaurs (
Beipiaosaurus) form an expanded Arctometatarsalia, though now joined by
Ornitholestes,
Aorun and
Compsognathus.
Coelurus becomes a tyrannosauroid.
26 steps- Ornithischian alvarezsaurids, as in Alifanov and Barsbold (2009).
Chilesaurus emerges as an alvarezsauroid. Note the true number is probably much higher since neither included alvarezsaurid has cranial material.
30 steps- Ceratosaurian ornithomimosaurs,
as in my half-joking post. They don't even come out by
Limusaurus or
Elaphrosaurus, instead Ornithomimosauria (including
Zuolong and
Gualicho) are sister to other ceratosaurs. How disappointing.
35 steps- Sauropodomorphan
Beipiaosaurus.
Falcarius stays by oviraptorosaurs, while
Beipiaosaurus ends up sister to
Guaibasaurus.
35 steps- Phytodinosaurian
Beipiaosaurus.
Falcarius stays by oviraptorosaurs, while
Beipiaosaurus is sister to
Chilesaurus as an ornithischian.
36 steps- Ornithomimosaurian
Elaphrosaurus.
Gualicho follows, and ornithomimosaurs move stemward to be sister to Tyrannoraptora.
36 steps- Megalosaurid abelisauroids, as in Paul (1988).
Megalosaurus moves to Abelisauria.
36 steps- Dromaeosaurid
Ornitholestes, as in Makovicky (1995).
Fukuivenator emerges as the most basal dromaeosaurid, and dromaeosaurids are the most basal pennaraptorans with oviraptorosaurs, scansoriopterygids, anchiornithids and troodontids successively closer to birds. This is equivalent to
my old post about getting dromaeosaurid evolution backwards.
37 steps- Bullatosauria. This actually moves ornithomimosaurs plus alvarezsauroids into Avialae to be sister to troodontids. I had to specify both
Zanabazar and
Sinornithoides as troodontids, because specifying
Zanabazar alone moves it into Ornithomimosauria without the other troodontids at a lower cost of 21 steps.
37 steps- Oviraptorosaurian
Sapeornis, as in Paul (2010). Oviraptorosaurs move to just closer to Aves than
Archaeopteryx, with scansoriopterygids closer to core oviraptorosaurs than
Sapeornis.
 |
| Phylogram from Huene (1923) showing his idea of what were carnosaurs vs. coelurosaurs. |
39 steps- Huene's (1923) Carnosauria vs. Coelurosauria dichotomy. For such an archaic concept, this works surprisingly well. The trick is that Huene's and Cau's Carnosauria are basically the same. By 1923, Huene had moved
Ceratosaurus to Coelurosauria and placed tyrannosaurids and
Elaphrosaurus there as well. His carnosaurs are
Megalosaurus,
Eustreptospondylus and
Allosaurus. Even looking at the taxa not included in Cau's analysis, most shake out right- coelurosaurian
Sarcosaurus,
Halticosaurus,
Procompsognathus,
Podokesaurus,
Betasuchus,
Genyodectes,
Proceratosaurus and
Thecocoelurus vs. carnosaurian
Magnosaurus,
Poekilopleuron,
Spinosaurus and
Metriacanthosaurus. There's a load of non-theropods in there and Huene got
Sarcosaurus? andrewsi,
Dryptosaurus and
Valdoraptor wrong, but still impressive. So this basically how many steps it takes to force carnosaurs stemward of Ceratosauria sensu lato.
43 steps- Sauriurine enantiornithines, as in Martin (1983). Basically constraining enantiornithines (
Bohaiornis and
Cruralispennia here) as closer to
Archaeopteryx than to Aves.
Rahonavis and
Balaur emerge as sauriurines, but surprisingly scansoriopterygids,
Sapeornis, jeholornithids,
Confuciusornis,
Zhongjianornis and
Protopteryx remain as closer to Aves ('Ornithurae' in BANDit terminology).
57 steps- Sauriurine enantiornithines and
Confuciusornis, as in Hou et al. (1995). This is more in line with BANDit thought, as not only enantiornithines,
Archaeopteryx and
Confuciusornis fall out as sauriurines, but also
Protopteryx,
Sapeornis, jeholornithids (Martin, 2004),
Vorona (Kurochkin, 2006),
Rahonavis and
Xiaotingia (those two as archaeopterygids). Unlike the plus 43 step tree, scansoriopterygids are outside Sauriurae plus 'Ornithurae' similar to Czerkas' hypothesis.
58 steps- Abelisaurid
Piatnitzkysaurus, as in Currie and Zhao (1994).
Condorraptor follows,
Eoabelisaurus also becomes an abelisaurid.
75 steps- 'Carnosauria' vs. 'Oviraptorosauria' of Russell and Dong (1994). The
Alxasaurus description is my most nostalgic technical paper, because it was the first I tracked down that wasn't in Science or Nature. The authors presented a strange new analysis of theropods, where tetanurines fell into 'Carnosauria' (
Baryonyx,
Yangchuanosaurus,
Allosaurus, dromaeosaurids and tyrannosaurids in successive order) and 'Oviraptorosauria' (ornithomimosaurs, therizinosauroids, oviraptorosaurs and troodontids in successive order). Needless to say, it doesn't hold up, even when topology within each clade is allowed to vary like it is here. Birds end up in 'Oviraptorosauria', so that would be Coelurosauria under current nomenclature.
78 steps- "Pneumatocrania", Holtz's (1994) concept combining oviraptorids, 'elmisaurids', tyrannosaurids, troodontids and ornithomimosaurs to the exclusion of dromaeosaurids and birds. Cau's matrix doesn't result in anything close to Holtz's topology for this clade, with troodontids sister to oviraptorosaurs (including scansoriopterygids), and ornithomimosaurs sister to tyrannosauroids with alvarezsauroids and therizinosaurs in a trichotomy with Tyrann+Ornithom. As with Bullatosauria,
Sinornithoides had to be specified as well.
81 steps- Arctometatarsalia sensu Holtz (1994). This is like "Pneumatocrania" except it excludes oviraptorids. In Cau's analysis, this results in most oviraptorosaurs (including scansoriopterygids) being maniraptorans, but 'elmisaurid'
Anzu being sister to
Zanabazar deep within Troodontidae. Again unlike Holtz's topology, tyrannosauroids, ornithomimosaurs, alvarezsauroids, therizinosaurians and
Fukuivenator are successively closer to troodontids.
84 steps- Huene's Pachypodosauria, where his carnosaurs are closer to sauropodomorphs than his coelurosaurs. Pachypodosauria ends up containing sauropodomorphs and ceratosaurs plus Cau's expanded Carnosauria, with every other theropod a coelurosaur.
[Edit] 100 steps-
Conservative BANDit topology. Here I specified taxa with stage III or IV feathers as birds, and retained
Heterodontosaurus, Plateosaurus,
Herrerasaurus,
Coelophysis,
Majungasaurus,
Megalosaurus,
Allosaurus and
Sinosauropteryx as
dinosaurs
theropods.
Forcing birds outside Saurischia, Dinosauria, Dracohors,
Dinosauriformes, etc. is difficult as it is actually easier to get Teleocrater
up in basal Coelurosauria than to break up those clades. But just
breaking up Theropoda into these two clades takes 83 steps.
Tyrannosauroids, ornithomimosaurs, alvarezsauroids and therizinosaurs
group with birds.
140 steps- Coelophysoid birds, as in Raath (1985). Other theropods known at the time were constrained as monophyletic relative to a Coelophysoidea containing
rhodesiensis,
Archaeopteryx,
Hesperornis,
Ichthyornis and
Meleagris.
Bicentenaria,
Fukuivenator, halszkaraptorids, scansoriopterygids and paraphyletic anchiornithids end up bridging the gap between coelophysoids and birds.
 |
| Paul's (1984) cladogram of predatory dinosaurs, after Raath (1990). It differs from Paul's actual printed cladogram where compsognathids are better interpreted as in an unresolved trichotomy between 'allosaurs' and other coelurosaurs, ornithomimids merely extend with a '?' falling between tyrannosaurids and Archaeopteryx, and oviraptorids extend with a '?' that falls on the troodontid plus bird branch. Note this differs from the PDW phylogeny in that megalosaurids are down by Procompsognathus and tyrannosaurids are sister to Protoavia. |
191+ steps- Kurochkin's (2006) diphyletic birds. BANDit Kurochkin had a weird hypothesis that
Archaeopteryx and enantiornithines were theropods, but
Confuciusornis,
Patagopteryx,
Ichthyornis,
Hesperornis and of course Aves are birds. These diverged at the typically vague BANDit level of Archosauromorpha or Archosauria, with no comment on where crocodylians, ornithischians, sauropodomorphs, etc. go.
It's again very hard to constrain in TNT since the program doesn't let the outgroup (Euparkeria) be specified, so if you constrain the next closest taxon (Teleocrater) to be outside of dinosauromorphs on one side and 'Ornithurae' on another, it's more parsimonious for TNT to force Teleocrater into Ornithothorces than to make that basal divergence. But even a weak version of Kurochkin's hypothesis where
Coelophysis and
Allosaurus are still theropods and lead to enantiornithines but are more closely related to 'Ornithurae' than
Teleocrater,
Lagerpeton,
Marasuchus,
Heterodontosaurus and
Plateosaurus results in 191 more steps.
Fukuivenator, halszkaraptorids, scansoriopterygids,
Balaur and
Zhongjianornis end up on the 'ornithurine' line.
Ignoring maniraptoromorphs (so as not to hint at Lori's topology) I'm most surprised by the robusticity of Cau's expanded Carnosauria, the rootward mobility of compsognathid-grade taxa, how unparsimonious carnosaurian megaraptorans are, and how parsimonious ceratosaurian megalosaurids and arctometatarsalian tyrannosaurids are. I think
Gualicho is the most interesting theropod right now in terms of just what it is, since its remains are decent but it can pretty easily move between ceratosaurs, tyrannosauroids and ornithomimosaurs.
Bicentenaria also finds its way into a suprisingly large number of hypotheses, so deserves a more detailed description.
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