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
aren't always sauropodomorphs, Pisanosaurus
is sometimes an ornithischian, Asilisaurus
are an unresolved trichotomy, Enantiornithes can be paraphyletic with Zhongjianornis
among them, and Fake Ornithuromorpha
is less resolved, as Patagopteryx
can be outside Hongshanornis
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.
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
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
1 step- Tyrannosauroid Sinocalliopteryx
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
2 steps- Maniraptoran Ornitholestes
2 steps- Hongshanornithid Parahongshanornis
, as in its original description.
Quite likely to be true
|Cast YPM 56693 of the Mononykus olecranus holotype pes in plantar view, courtesy of Senter.|
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
is sister to Averostra.
3 steps- Theropodan Herrerasaurus
. 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
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
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
form a silesaur grade to either side of Silesauridae.
4 steps- Phytodinosauria. Eoraptor
are sister to Dinosauria, while herrerasaurs and Eodromaeus
4 steps- Ornithischian Chilesaurus
. Ornithoscelida occurs.
4 steps- Theropodan Eoraptor
, herrerasaurs and Eodromaeus
4 steps- Abelisaurid Eoabelisaurus
, as in its original description.
4 steps- Metriacanthosaurids outside Allosauria (Allosaurus
, so this also covers carcharodontosaurid Neovenator
4 steps- Tyrannosauroid Compsognathus
, as in Olshevsky (1991). Surprised this one is so parsimonious. A Compsognathidae with Aorun
are the basalmost tyrannosauroids, with Sinocalliopteryx
, Coeluridae including Tanycolagreus
successively closer to core tyrannosauroids.
4 steps- Maniraptoromorph Tanycolagreus
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
, and Cau said in a comment to the last post Jianchangosaurus
was still an alvarezsauroid even after adding Erlikosaurus
. I'm not revealing much by saying the Lori analysis finds Jianchangosaurus
to be a therizinosaur between Falcarius
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
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
, because in the constrained trees Carnosauria still has the same content as Cau's MPTs. Sinosauropteryx
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.
6 steps- Non-eusaurischian saurischian Eoraptor
follows, but herrerasaurs and Eodromaeus
6 steps- Theropodan Guaibasaurus
. Non-dinosaurian Eoraptor
, 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
7 steps- Maniraptoran Compsognathus
7 steps- Paravian alvarezsaurids, though note the lack of parvicursorines probably affects these numbers. They (including Jianchangosaurus
) emerge as the most basal paravians.
7 steps- Basal paravian Anchiornis
, scansoriopterygids, Serikornis
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
|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
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
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
9 steps- Classic late 80s to early 90s topology where Staurikosaurus
is sister to Herrerasaurus
plus Dinosauria. Tawa
are closer to dinosaurs than both, while Sanjuansaurus
9 steps- Piatnitzkysaurus
outside Orionides, as in Rauhut (2003). Condorraptor
, and megalosauroids fall outside Avetheropoda. Surprised this is so high.
9 steps- Carnosaurian Tyrannosaurus
, which brings megaraptorans, Gualicho
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
successively closer to the 'core tyrannosauroid' clade of Eotyrannus
, megaraptorans and Tyrannosaurus
are now maniraptoromorphs.
11 steps- Alvarezsauroid Nqwebasaurus
. Alvarezsauroids emerge sister to ornithomimosaurs, with Haplocheirus
forming a basal  arcto
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).
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
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
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
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
16 steps- Non-avetheropod Sinraptor
as in Longrich (2002). Carnosauria
becomes a grade, Acrocanthosaurus
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
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
) 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
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
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
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
, instead Ornithomimosauria (including Zuolong
) are sister to other ceratosaurs. How disappointing.
35 steps- Sauropodomorphan Beipiaosaurus
stays by oviraptorosaurs, while Beipiaosaurus
ends up sister to Guaibasaurus
35 steps- Phytodinosaurian Beipiaosaurus
stays by oviraptorosaurs, while Beipiaosaurus
is sister to Chilesaurus
as an ornithischian.
36 steps- Ornithomimosaurian Elaphrosaurus
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
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
. Even looking at the taxa not included in Cau's analysis, most shake out right- coelurosaurian Sarcosaurus
vs. carnosaurian Magnosaurus
. There's a load of non-theropods in there and Huene got Sarcosaurus? andrewsi
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
here) as closer to Archaeopteryx
than to Aves. Rahonavis
emerge as sauriurines, but surprisingly scansoriopterygids, Sapeornis
, jeholornithids, Confuciusornis
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
fall out as sauriurines, but also Protopteryx
, jeholornithids (Martin, 2004), Vorona
(Kurochkin, 2006), Rahonavis
(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
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
, 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.
BANDit topology. Here I specified taxa with stage III or IV feathers as birds, and retained Heterodontosaurus, Plateosaurus
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
, 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
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
are still theropods and lead to enantiornithines but are more closely related to 'Ornithurae' than Teleocrater
results in 191 more steps. Fukuivenator
, halszkaraptorids, scansoriopterygids, Balaur
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.
- Huene, 1923. Carnivorous Saurischia in Europe since the Triassic. Bulletin of
the Geological Society of America. 34, 449-458.
Martin, 1983. The origin and early radiation of birds. in
Brush and Clark, (eds.). Perspectives in Ornithology. 291-338.
Paul, 1984. The archosaurs: A phylogenetic study. In Reif and Westphal (eds.). Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers. 175-180.
Raath, 1985. The theropod Syntarsus
and its bearing on the origin of
birds. In Hecht, Ostrom, Viohl and Wellnhofer (eds.). The Beginnings of Birds.
Freunde des Jura-Museums Eichstätt, Eichstätt. 219-227.
Bakker, Williams and Currie, 1988. Nanotyrannus
, a new genus of pygmy
tyrannosaur, from the latest Cretaceous of Montana. Hunteria. 1, 1-30.
Paul, 1988. Predatory Dinosaurs of the World. Simon &
Schuster, New York. 464 pp.
Raath, 1990. Morphological variation in small theropods and its meaning in systematics:
Evidence from Syntarsus rhodesiensis
. In Carpenter and Currie (eds.).
Dinosaur Systematics: Approaches and Perspectives. Cambridge University Press,
Britt, 1991. Theropods of Dry Mesa Quarry (Morrison Formation, Late Jurassic),
Colorado, with emphasis on the osteology of Torvosaurus tanneri
Young University Geology Studies. 37, 1-72.
Olshevsky, 1991. A Revision of the Parainfraclass Archosauria Cope, 1869, Excluding
the Advanced Crocodylia. Mesozoic Meanderings. 2, 196 pp.
Novas, 1992. La evolucion de los dinosaurios carnivoros. In Sanz and Buscalioni (eds.). Los Dinosaurios y Su Entorno Biotico:
Actas del Segundo Curso de Paleontologia in Cuenca. Instituto "Juan Valdez",
Cuenca, Argentina. 126-163.
Currie and Zhao, 1994. A new carnosaur (Dinosauria, Theropoda) from the Jurassic
of Xinjiang, People's Republic of China. Canadian Journal of Earth Sciences.
Holtz, 1994. The phylogenetic position of the Tyrannosauridae: Implications
for theropod systematics. Journal of Paleontology. 68(5), 1100-1117.
Russell and Dong, 1994. The affinities of a new theropod
from the Alxa Desert, Inner Mongolia, People’s Republic of China. Canadian
Journal of Earth Sciences. 30(10), 2107-2127.
Currie, 1995. Phylogeny and systematics of theropods (Dinosauria). Journal of
Vertebrate Paleontology. 15(3, 25A.
Hou, Zhou, Gu and Zhang, 1995. Confuciusornis sanctus
, a new Late Jurassic
sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551.
Forster, Sampson, Chiappe and Krause, 1998. The theropod ancestry of birds:
New evidence from the Late Cretaceous of Madagascar. Science. 279, 1915-1919.
Sereno, 1999. The evolution of dinosaurs. Science. 284,
Holtz, 2000. A new phylogeny of the carnivorous dinosaurs. GAIA. 15, 5-61.
Kischlat, 2000. Tecodoncios: A aurora dos Arcosaurios no Triassico. in Holz
and De Rose (eds.). Paleontologia do Rio Grande do Sul. 273-316.
Longrich, 2002. Systematics of Sinosauropteryx
. Journal of Vertebrate
Paleontology. 22(3), 80A.
Maryanska, Osmolska and Wolsan, 2002. Avialan status for
Oviraptorosauria. Acta Palaeontologica Polonica. 47(1), 97-116.
Paul, 2002. Dinosaurs of the Air. The Johns Hopkins
Baltimore. 460 pp.
Rauhut, 2003. The interrelationships and evolution of basal theropod dinosaurs.
Special Papers in Palaeontology. 69, 1-213.
Martin, 2004. A basal archosaurian origin for birds. Acta Zoologica Sinica.
Carr, 2006. Is Guanlong
a tyrannosauroid or a subadult Monolophosaurus
Journal of Vertebrate Paleontology. 26(3), 48A.
Kurochkin, 2006. Parallel evolution of theropod dinosaurs and birds. Entomological Review. 86 (Supp. 1), S45-S58.
Smith, Makovicky, Hammer and Currie, 2007. Osteology of Cryolophosaurus ellioti
(Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications
for early theropod evolution. Zoological Journal of the Linnean Society. 151,
Alifanov and Barsbold, 2009. Ceratonykus oculatus
gen. et sp. nov.,
a new dinosaur (?Theropoda, Alvarezsauria) from the Late Cretaceous of Mongolia.
Paleontological Journal. 43(1), 94-106.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
Alifanov and Saveliev, 2011. Brain structure and neurobiology of alvarezsaurians
(Dinosauria), exemplified by Ceratonykus oculatus
the Late Cretaceous of Mongolia. Paleontological Journal. 45(2), 183-190.
Lee and Worthy, 2011. Likelihood reinstates Archaeopteryx
as a primitive bird. Biology Letters. 8(2), 299-303.
Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod
from China and the origin of Avialae. Nature. 475, 465-470.
Carrano, Benson and Sampson, 2012. The phylogeny of
Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology. 10(2),
Senter, Kirkland, DeBlieux, Madsen and Toth, 2012. New dromaeosaurids (Dinosauria:
Theropoda) from the Lower Cretaceous of Utah, and the evolution of the dromaeosaurid
tail. PLoS ONE. 7(5), e36790.
Agnolin and Novas, 2013. Avian ancestors: A review of the phylogenetic relationships of the theropods Unenlagiidae, Microraptoria, Anchiornis
and Scansoriopterygidae. Springer Netherlands. 96 pp.
Novas, Agnolin, Ezcurra, Porfiri and Canale, 2013. Evolution
of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia. Cretaceous Research. 45, 174-215.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx
provides insights into the
evolution of pennaceous feathers. Nature. 511, 79-82.
Baron, 2017. Pisanosaurus mertii
and the Triassic ornithischian crisis: Could phylogeny offer a solution? Historical Biology. DOI: 10.1080/08912963.2017.1410705
Cau, 2018. The assembly of the avian
body plan: A 160-million-year long process. Bollettino della Società
Paleontologica Italiana. 57(1), 1-25.