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Re: Our current understanding of Mesozoic bird phylogeny
David Marjanovic wrote-
the new Yixianornis paper (Clarke et al., 2006)
I have managed to miss that one. Which journal was it in?
Clarke, J. A., Zhou, Z., and Zhang, F., 2006, Insight into the evolution of
avian flight from a new clade of Early Cretaceous ornithurines from China
and the morphology of Yixianornis grabaui: Journal of Anatomy, v. 208, p.
Two characters of my own (median sternal process expanded distally;
mtIV longer than mtIII) that I thought might affect enantiornithine
Yes, but the first looks ontogenetic to me. Or, more probably, _partially_
ontogenetic (there's probably a phylogenetic signal in when in ontogeny the
sternum ossifies that far).
I agree. Indeed, this is probably true of most sternal process characters.
Caudal vertebral count was revised to be a total
count and not just of free vertebrae.
Good, but how did you count the vertebrae in the pygostyle?
Dalingheornis (a juvenile) hadn't fused its pygostyle yet and has twenty
caudals, while the Yixian enantiornithine embryo has ~18. This fits with
estimations of ~8-15 caudals being incorporated into the pygostyles of other
- *Wyleyia* as the basalmost enantiornithean is interesting.
Very poorly supported. It's less derived than Protopteryx due to the
absence of a well-developed fossa on midline of the proximal humerus.
- *Vorona* and *Elsornis* on the next node is also interesting.
Vorona has a few likely positions. After I modified some codings for the
entries on my website, Vorona came out as a liaoningornithid instead. This
was based on several characters shared with Liaoningornis-
fossa for insertion of capital ligament on femoral head (also in
Confuciusornis and Apsaravis+Passer; unknown in Liaoningornis<Gobipteryx and
Eoalulavis); metatarsals at least partially fused distally (also in
Changchengornis, Avisaurus gloriae and Euornithes; unknown in Eoalulavis);
trochlea of metatarsal II subequal in width to III (also in
non-enantiornithines and Longipterygidae; unknown in Eoalulavis); metatarsal
IV not reduced in width compared to II and III (also in non-enantiornithines
and those more basal than Longipteryx; unknown in Eoalulavis).
Another possible position is as a basal euornithine.
Elsornis moved up a couple nodes past Protopteryx and Iberomesornis to be
the basalmost euenantiornithine. This position is congruent with the one
found in its original description and was found to be highly possible in my
| |?-Jibeinia adult
Oho! What's that?
Jibeinia coded with juvenile characters as unknown. I'll post more on
| | |--Hebeiornis
| | |--LP-4450-IEI
| | `--+--GMV 2158
| | `--GMV-2159
Curiouser and curiouser...
And largely based on Clarke's IMHO poor trochlear extent character. When
it's deleted, Hebeiornis becomes a basal gobipterygid (based on
posterolateral sternal processes expanded less than twice minimum width
shared with Boluochia and distal end of metatarsal II strongly curved
Yungavolucris falls into an uncertain basal position. It's excluded from
Longipterygidae due to its broad trochlea on metatarsal II, from
Sinornis+Concornis due to its lack of a strong plantar projection on the
medial rim of metatarsal III's trochlea, and from Gobipteryx<Sinornis due to
the lack of a strongly anteriorly inclined proximal tarsometatarsal surface.
Within the latter clade, it also lacks the gobipterygid synapomorphy of a
medially curved metatarsal II trochlea, and three liaoningornithid
synapomorphies (metatarsals at least partially fused distally; trochlea of
metatarsal II subequal in width to III; metatarsal IV not reduced in width
compared to II and III).
LP-4450-IEI (the Catalan nestling) and GMV-2159 (a Yixian juvenile) are more
derived than Eocathayornis based on their short manus. Further positioning
is probably difficult.
| | |--Boluochia
| | `--Gobipteryx
Are they held together by anything else than their toothless pmx?
Yes. The distal end of metatarsal II is curved medially (as in Hebeiornis,
Avisaurus and Soroavisaurus, which are all gobipterygids in the revised
| | |--Avisaurus
| | `--Soroavisaurus
| | |--Eoalulavis
| | `--Liaoningornis
I like this very much! :-) Is there any chance that *Cuspirostrisornis* is
in or next to this clade?
Well, the topology changed a bit in the revised version. Here's what's
going on my website-
| |--Eoenantiornis buhleri
| `--+--Sinornis santensis
| `--+--"Cathayornis" caudatus
| |--Concornis lacustris
| `--Neuquenornis volans
| |?-Vorona berivotrensis
| |--Eoalulavis hoyasi
| `--Liaoningornis longidigitus
As for Cuspirostrisornis-
The pneumotricipital fossa is character only currently known in
euenantiornithines among Mesozoic birds, though uncertain in more basal
Enantiornithes besides being absent in the very basal Wyleyia. The slender
metatarsal IV is similar to Lectavis and more derived enantiornithines.
Cuspirostrisornis seems less derived than Protopteryx due to its narrow
metatarsal II trochlea. The elongate ulna is similar to both protopterygids
and Otogornis+Eocathayornis. If the illustration is accurate a lateral
coracoid process may exclude it from the Iberomesornis+Enantiornis clade.
However, the posteromedial sternal processes are like the
Longipteryx+Enantiornis clade. Yet the tibiotarsal intercondylar groove is
said to be broad, which would be unlike that clade. The short rostrum is
unlike longipterygids, yet the toothless maxilla and narrow metatarsal II
trochlea are similar. On the other hand, the short nasal process of the
premaxilla is like Eocathayornis and more derived enantiornithines (and
Protopteryx as well). The concave lateral coracoid and absent olecranal
fossa are unlike most members of this clade though. The blunt posteromedial
sternal processes are unlike cathayornithids, while the short sternum,
posterolateral and posteromedial sternal processes, distally unfused
tarsometatarsus and slender metatarsal IV are all unlike liaoningornithids
(though the narrow metatarsal II trochlea is similar). The distal end of
metatarsal II is not medially curved, unlike gobipterygids, while the
toothed premaxilla is unlike the Boluochia+Gobipteryx subclade. This results
in Cuspirostrisornis more parsimoniously being a protopterygid, though only
a couple more steps are needed to make it a longipterygid or as basal as
I guess its many teeth pull it towards *Yanornis*?
Nope. Tooth count wasn't used by any of the analyses I combined. It's the
basalmost enantiornithine in my revised topology though, in a trichotomy
with Wyleyia. It's only an enantiornithine based on- sternal posteromedian
process acutely narrow (also in Changchengornis, Confuciusornis dui,
Hongshanornis and Gansus; absent in Eoalulavis and Liaoningornis);
ventrodistal margin of humerus projected significantly distal to dorsodistal
margin, distal margin angling strongly ventrally (also in Piksi and
Apsaravis). I bet was a euornithine in the prior topology based on its
dorsoventrally curved scapula, elongate sternum, and/or elongate
So you're using the older definition that does not mention *Vorona* :-P
Seems to be most useful considering Vorona may be an enantiornithine.
875 steps- Otogornis as a euornithine ambiortiform
This is Kurochkin's (1999) idea, based on his reinterpretation of the
material. Even if I were to grant Kurochkin's alternative morphology
(coracoid tubercle = procoracoid process), the tree would still be 873
or so, showing Kurochkin's identifications for these are probably wrong.
Yup. Several paleornithologists have noted that Otogornis is an
enantiornithine as well, though nobody's examined it cladistically in a
published analysis yet.
871 steps- Protopteryx and Longipteryx successively closer to
This kind of paraphyletic Enantiornithes was proposed by me back in 2001
on the DML, based on six characters, all of which were examined here.
Notably, far more enantiornithine characters have been described in it now
than were proposed by Zhang et al. (2001). I now officially reject this
Ah. Too bad. The 3rd-finger lengths fitted so well :-)
Now we know Hongshanornis had two phalanges on manual digit III, making its
reduction probably convergent between derived enantiornithines and derived
862 steps- confuciusornithids as enantiornithines
Surprisingly, this reduced version of Sauriurae (which shouldn't be termed
Sauriurae, as it lacks Archaeopteryx) is highly parsimonious. The
of Chiappe's characters makes it slightly less so than the traditional
(western) ornithothoracine view.
Ornithothoraces is only supported by the following, as far as this matrix
less than thirteen dorsal vertebrae (also in Harpymimus+Ornithomimus and
Oviraptoriformes; unknown in Confuciusornithidae); scapulacoracoid mobily
jointed (also in Rahonavis and Shenzhouraptor); distal end of posterodistal
sternal process fused to sternum (absent in Liaoningornithidae,
Cuspirostrisornis, Hesperornis and Ichthyornis); projected carina on sternum
(absent in Jibeinia, Longchengornis, Eoalulavis and Hesperornis; also in
Mononykinae and Jixiangornis); interclavicular angle <68 degrees (absent in
Hesperornis); capital groove developed on proximal humerus (absent in
Elsornis, Apsaravis and Ambiortus; also in Gallimimus, Neimongosaurus,
Therizinosauridae, Mononykus, Deinonychus and Bambiraptor); dorsal condyle
of distal ulna developed as semilunate ridge (absent in Eocathayornis; also
in Heyuannia); metacarpal I fused to carpometacarpus (absent in Hebeiornis
(ontogenetic?); also in Patagonykus+Mononykus, Avimimus and Heyuannia); less
than four phalanges on manual digit III (also in Tyrannosauridae,
Caudaipteryx, Jinfengopteryx and Omnivoropterygidae); alula present (also
somewhat developed in Microraptor gui).
861 steps- Odontornithes
Just four more steps in addition to 857! Wow. Where does *Gansus* go in
In Odontornithes, if I remember correctly.
860 steps- Apsaravis closer to Carinatae than Hesperornithes
This was suggested in the original description of Apsaravis (Norell and
Clarke, 2001), but found to be slightly less parsimonious by Clarke and
Norell (2002). The change was due to correcting a few codings between
In sum, we need a lot more basal hesperornithean fossils, or the long
branch of Hesperornithes will continue to attach itself to wherever it
I guess I could code Enaliornis and see what that does.
Does anything surprising occur in trees with 858 steps? :o)
Well, the basal enantiornithine tree looks like this now-
| |?-Cuspirostrisornis houi
| |--Protopteryx fengningensis
| `?-Noguerornis gonzalezi
| `--Incolornis martini
| |--Longipteryx chaoyangensis
| `--Longirostravis hani
| `--Otogornis genghisi
In Euornithes, chaoyangiids and Patagopteryx can be rearranged extremely
easily. Also, Ambiortus has an uncertain position in the basal part of the
clade. Haven't really looked into that part of the tree yet. After doing
this bird stuff months ago, I've been busy coding cranial characters lately
in my coelurosaur analysis. Almost done with them finally.