The strange skull of the violet turaco (genus: Macrophaga violate)

Figure 1. The violet turaco (genus: Musophaga) with its skull and a related skeleton.

Figure 1. The violet turaco (genus: Musophaga) with its skull and a related skeleton. Note the expanded nasals rimmed by prefrontals. The spectacular color and jungle habitat are clues that turacos are in the same family as birds of paradise.

Musophaga violacea (Isert 1788; 48 cm long) is the extant violet turaco, originally considered a near-passerine. Here it nests with the trumpeter (genus: Psophia, Fig. 2). In Musophaga the legs and sternum are shorter. The pelvis is deeper and the tail is more robust.

Figure 3. Psophia the trumpeter in vivo and skeleton.

Figure 2. Psophia the trumpeter in vivo and skeleton.

References
Isert 1788. Kurze Beschreibung und Abbildung einiger Vögel aus Guinea. – Schriften der Berlinischen Gesellschaft Naturforschender Freunde 9: 16-20

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Aceratherium vs. Paraceratherium

Aceratherium is a hornless rhino (Figs 2-4).
Paraceratherium is a GIANT hornless horse (Fig. 1). Even so, the two are similar enough that that latter was named for the former. Thereafter Paraceratherium became known as a rhino.

Figure 1. Equus the horse shares many traits with Paraceratherium, the giant rhino/horse.

Figure 1. Equus the horse shares many traits with Paraceratherium, the giant three-toed horse.

However,
and as we learned earlier by testing prior assumptions in the large reptile tree (LRT, 1318 taxa, subset Fig. 5), Aceratherium nested between rhinos and brontotheres. Paraceratherium nested with other large three-toed horses.

Fig. 1. Aceratherium skeletal mount. This hornless rhino is transitional to brontotheres, not indricotheres (= paraceratheres).

Fig. 2 Aceratherium skeletal mount. This hornless rhino is transitional to brontotheres, not indricotheres (= paraceratheres) in the LRT.

Even so,
the convergence is impressive! No wonder earlier workers named the one for the other.

Figure 2. Aceratherium acutum skull drawing and fossil.

Figure 3. Aceratherium acutum skull drawing and fossil.

Convergence is rampant within the LRT.
For example, we’ve seen mysticetes and odontocetes converge so much we call them all ‘whales’ or ‘cetaceans‘, two terms that need to be dumped in favor of something more in keeping with their phylogenetic nestings. The same has happened with Aceratherium and Paraceratherium. The details of their skeletal traits distinguish them. You can examine those traits in a MacClade file by request.

Figure 1. Indricothere skulls to scale along with horse and rhino skulls.

Figure 4. Indricothere skulls to scale along with horse and rhino skulls.

Perhaps this is just one more instance of paleontology
turning a blind eye toward testing a wider gamut of taxa to validate prior hypotheses… or invalidate them. That’s why the LRT is here: to test prior hypotheses.

Figure 5. Various ungulates and kin subset of the LRT. Here Aceratherium, a hornless rhino, does not nest with Paraceratherium, a giant three-toed horse.

Figure 5. Various ungulates and kin subset of the LRT. Here Aceratherium, a hornless rhino, does not nest with Paraceratherium, a giant three-toed horse.

Shifting all the paraceratheres
over to the aceratheres adds 21 steps to the LRT.

Aceratherium incisivum (Kaup 1832; originally Rhinoceros incisivum, Cuvier 1822; Miocene; 2.3m long) nests with short-legged Metamynodon and shares with it long anterior dentary teeth, a straight jugal and a short nasal. Aceratherium lacks an upper canine.

Figure 2. GIF movie (3 frames) showing what is known of the skeletons of Baluchitherium and Indricotherium. Note the more horse-like morphology.

Figure 6. GIF movie (3 frames) showing what is known of the skeletons of Baluchitherium and Indricotherium. Note the more horse-like morphology.

Paraceratherium transouralicum  (P. bugtiense holotype, Pilgrim 1908; Baluchitherium, Osborn 1923; late Oligocene, 34-23mya; 4.8m shoulder height, 7.4m long) was long considered a giant hornless rhinoceros, but here nests with the horse, Equus. They share a long neck, straight ventral dentary and the retention of premaxillary teeth, among other traits. Paraceratherium retains three toes, as in ancestral horse/rhinos like Heptodon and Hyracotherium.

Figure 3. In the LRT Mesohippus nests basal to horses and indricotheres.

Figure 7. Mesohippus, the last common ancestor in the LRT to horses and indricotheres.

References
Chow M and Chiu C-S 1964. An Eocene giant rhinoceros. Vertebrata Palasiatica, 1964 (8): 264–268.
Cuvier G 1822a. Recherches sur les ossements fossiles. Tome second, G. Doufor et d’Ocagne éd., Paris, – (1822b). Tome troisième, – (1824). Tome cinquième.
Forster-Cooper C 1911. LXXVIII.—Paraceratherium bugtiense, a new genus of Rhinocerotidae from the Bugti Hills of Baluchistan.—Preliminary notice. Annals and Magazine of Natural History Series 8. 8 (48): 711–716. doi
Forster-Cooper C 1924. On the skull and dentition of Paraceratherium bugtiense: A genus of aberrant rhinoceroses from the Lower Miocene Deposits of Dera Bugti. Philosophical Transactions of the Royal Society B: Biological Sciences. 212 (391–401): 369–394.
Granger W and Gregory WK 1935. A revised restoration of the skeleton of Baluchitherium, gigantic fossil rhinoceros of Central Asia. American Museum Novitates. 787: 1–3.
Kaup J 1832. Über Rhinoceros incisivus Cuv., und eine neue Art, Rhinoceros schleier-macheri, Isis von Oken, Jahrgang1832 (8: 898-904.
Lucas SG and Sobus JC 1989. The Systematics of Indricotheres”. In Prothero DR and Schoch RM eds. The Evolution of Perissodactyls. New York, New York & Oxford, England: Oxford University Press: 358–378. ISBN 978-0-19-506039-3.
Osborn HF 1923. Baluchitherium grangeri, a giant hornless rhinoceros from Mongolia. American Museum Novitates. 78: 1–15. PDF
Pilgrim GE 1910. Notices of new mammalian genera and species from the Tertiaries of India. Records of the Geological Survey of India. 40 (1): 63–71.
Wood HE 1963. A primitive rhinoceros from the Late Eocene of Mongolia. American Museum Novitates 2146:1-11.

wiki/Juxia
wiki/Paraceratherium
wki/Indricotheriinae
wiki/Metamynodon
wiki/Aceratherium

What is Rhamphocephalus? An earlier bird.

Some confusion in the academic literature today
as a Middle Jurassic fossil known since the 19th century is grossly misidentified.

Figure 2. Rhamphocephalus in situ, traced by Seeley, traced by O'Sullivan and Martill and Rhamphorhynchus graphic from Wellnhofer 1975.

Figure 1. Rhamphocephalus in situ, traced by Seeley, traced by O’Sullivan and Martill and, for comparison sake, Rhamphorhynchus graphic from Wellnhofer 1975, all appearing in O’Sullivan and Martill 2018. Rhamphocephalus has been traditionally identified as a pterosaur. That paradigm was challenged by O’Sullivan and Martill 2018, but that challenge is challenged again here.

Today a paper by O’Sullivan and Martill 2018
redescribes several fossils from the Middle Jurassic (165–166 mya) of England, traditionally ascribed to the wastebasket pterosaur taxon, Rhamphocephalus prestwichi (type, Seeley, 1880;  OUM J.28266; Figs. 1–4). Most of the disassociated specimens (individual jaws, limbs) are clearly pterosaurian. One (the goose-sized skull roof) is clearly not pterosaurian.

Figure 2. Rhamphorhynchus compared to a large choristodere, Simoedosaurus, and to a large thalattosuchian, Pelagosaurus. There is absolutely no match here.

Figure 2. O’Sullivan and Martill compared Rhamphocephalus to a large choristodere, Simoedosaurus, and to a large thalattosuchian, Pelagosaurus. There is absolutely no match here, either in size or morphology. Colors and ‘to scale’ Rhamphocephalus images added for clarity.

The holotype of Rhamphocephalus prestwichi,
“an isolated skull table, is found to be a misidentified crocodylomorph skull,” according to O’Sullivan and Martill, who illustrated the 10x smaller specimen alongside a dorsal view of the 3m long thalattosuchian (marine) croc, Pelagosaurus, from the Lower Jurassic of England and, perhaps to cover all their bases, flipped anterior-to-posterior alongside the Paleocene choristodere, Simoedosaurus (Fig. 2). Note: the authors did not illustrate their comparative taxa to scale (as shown above), perhaps because the taxa are 10x larger and are morphologically dissimilar. So why make such comparisons? I don’t understand the logic of these paleontologists making such readily disprovable comparisons.

Figure 1. The skull roof named Rhamphocephalus here with bones and teeth colored.

Figure 3. The in situ specimen of Rhamphocephalus here with bones and teeth colored. At standard monitor 72 dpi resolution, this image is 2x life size. Perhaps this skull can be µCT scanned for buried data. Some palatal elements are peeking out from the antorbital fenesrae and nares. The dentary teeth make a few appearances, too. This is a sharp-tipped taxon.

Traced here
using DGS methods (Fig. 3) and phylogenetically tested in the large reptile tree (LRT, 1321 taxa) goose-sized Rhamphocephalus nests with the hummingbird-sized, Hongshanornis (Fig. 2), an Early Cretaceous toothed bird from China. Hongshanornis is one of the few toothed birds in which the orbits are further forword, creating a longer cranium to match that of Rhamphocephalus. A suite of other skull traits are likewise most closely matched to Hongshanornis. The Rhamphocephlaus specimen appears to be complete without obvious breaks either at the toothy tip of the skull or the occiput. More teeth and bones were identified here.

Figure 2. Rhamphorcephalus in situ compared to Hongshanornis in situ to scale and enlarged to match.

Figure 2. Rhamphorcephalus in situ compared to Hongshanornis in situ to scale and enlarged to match skull length. To scale image (above) is 1.25x actual size, much too small for sea crocs. similar in size to pre-birds. Hongshanornis is a tiny bird, similar in size to a hummingbird.

Ironically
the authors report, “The earliest known record of Bathonian pterosaurs is an account of “fossil bird bones” from the Taynton Limestone Formation of Stonesfield by an anonymous author A.B., appearing in the March edition of the Gentleman’s Magazine of 1757.” For this specimen, and only this specimen, A.B. got it right. The other specimens are clearly pterosaurian.

Historically
the authors report, “This specimen is exposed on a limestone slab in dorsal view and was assigned to Pterosauria based on its perceived thin bone walls. Seeley (1880) noted that the arrangement of bones was more crocodilian than pterosaurian and considered this construction diagnostic of the new taxon. Significantly he (Seeley 1880: 30) stated: “I shall be quite prepared to find that all the ornithosaurians from Stonesfield belong to this or an allied genus which had Rhamphorhynchus for its nearest ally.” In the LRT crocodilians are closer to birds than pterosaurs are.

Figure 6. Rhamphocephalus chronologically precedes the Solnhofenbirds by several million years making it the oldest known bird.

Figure 6. Rhamphocephalus chronologically precedes the Solnhofenbirds by several million years making it the oldest known euornithine bird.

Is the Middle Jurassic too early for a toothed bird?
Perhaps not. Remembet that all of the Late Jurassic Solnhofen birds, traditionally named as one genus, Archaeopteryx, already represent a diverse radiation of taxa, suggesting an earlier genesis for that radiation. Rhamphocephalus indicates that the original bird radiation had its genesis at least 15 million years earlier. 

It is unfortunate
that O’Sullivan and Martill attempted to force fit the skull specimen into a crocodilian clade when no aspect of the thin-walled, goose-sized skull of Rhamphocephalus is crocodilian (Fig. 2)… or choristoderan (when flipped backwards!!). Adding Rhamphocephalus to the LRT gives it a single most parsimonious sister among all the toothed birds and a special Middle Jurassic place in the origin of birds story. All the details fit.

Working with a high-resolution image
of Rhamphocephalus (Fig. 3) copied from a PDF of the paper by O’Sullivan and Martill made this all possible.

Once again, to determine the affinities of a specimen it is more important to have a wide gamut of taxa to work with than to have firsthand access to the specimen itself. No one likes this method, but it clearly works time after time and to not use it invites discredit.

USE THE LRT. That’s what it is here for.

References
O’Sullivan M and Martill DM 2018. Pterosauria of the Great Oolite Group (Bathonian, Middle Jurassic) of Oxfordshire and Gloucestire. Acta Palaeontologica Polonica 63 (X): xxx–xxx, 2018 https://doi.org/10.4202/app.00490.2018
Seeley HG 1880. On Rhamphocephalus prestwichi Seeley, an Ornithosaurian from the Stonesfield Slate of Kineton. Quart. J. Geol. Soc. 36: 27-30.

wiki/Rhamphocephalus

Dorsetisaurus: a Mesozoic tegu, not an anguimorph

Known from the Early Cretaceous of Mongolia
and the Late Jurassic of Portugal, Dorsetisaurus purbeckensis (BMNH R.8129, skull width: 1.4cm; Hoffstetter 1967; Fig. 1) was attributed to the clade of glass lizards (Anguimorpha) originally and in two later papers. Evans 2006 nested it between the highly derived legless skink, Amphisbaenia, and the basal gecko (in the LRT), Chometokadmon (which Evans considered an anguimorph).

FIgure 1. Dorsetisaurus bits and pieces restored here and scored nests in the LRT with Tupinambis, the extant tegu.

FIgure 1. Dorsetisaurus bits and pieces restored here and scored nests in the LRT with Tupinambis, the extant tegu.

By contrast
in the large reptile tree (LRT, 1318 taxa) Dorsetisaurus nests with the basal scerloglossan, lacertoid, teiid, Tupinambis (Fig. 2), the extant tegu lizard. Even the slight notch in the ventral maxilla is retained over 120 million years of evolution.

Figure 2. Tupinambis is the extant tegu lizard, a sister to Dorseitsaurus in the LRT.

Figure 2. Tupinambis is the extant tegu lizard, a sister to Dorseitsaurus in the LRT.

On a side note:

Gauthier et al. 2012 put together two squamate trees of life, one based on traits, another based on genes. Neither matches the LRT, which includes more fossil taxa.

References
Evans SE, Raia P, Barbera C 2006. The Lower Cretaceous lizard genus Chometokadmon from Italy. Cretaceous Research 27:673-683.
Gauthier, JA, et al. 2012. Assembling the squamate tree of life: Perspectives from the phenotype and the fossil record. Bulletin of the Peabody Museum of Natural History 53.1 (2012): 3-308.
Hoffstetter  R 1967.
Coup d’oeil sur les Sauriens (lacertiliens) des couches de Purbeck (Jurassique supérieur d’Angleterre Résumé d’un Mémoire). Colloques Internationaux du Centre National de la Recherche Scientifique 163:349-371.

wiki/Dorsetisaurus
http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=38022

False positives in an LRT subset lacking fossil taxa

I think you’ll find this phylogenetic experiment both
gut-wrenching and extremely illuminating. While reading this, keep in mind the importance of having/recovering the correct outgroup for every clade and every node. That can only be ascertained by including a wide gamut of taxa—including fossils. Adding taxa brings you closer and closer to echoing actual events in deep time while minimizing the negative effects of not including relevant/pertinent taxa.

Today you’ll see
what excluding fossil taxa (Fig. 1) will do to an established nearly fully resolved cladogram, the large reptile tree (LRT, 1318 taxa). Earlier we’ve subdivided the LRT before, when there were fewer taxa in total. Here we delete all fossil taxa (except Gephyrostegus, a basal amniote used to anchor the cladogram because PAUP designates the first taxon the outgroup).

PAUP recovers 250+ trees
on 264 (~20%) undeleted extant taxa.

  1. Overall lepidosaurs, turtles, birds and mammals nest within their respective clades.
  2. Overall lepidosaurs nest with archosaurs and turtles with mammals, contra the LRT, which splits turtles + lepidosaurs and mammals + archosaurs as a basal amniote dichotomy.
  3. Overall mammals are not the first clade to split from the others, contra traditional studies. All pre-mammal amniotes in the LRT are extinct.
  4. Within lepidosaurs, the highly derived horned lizards and chameleons are basal taxa, contra the LRT, which nests Iguana as a basal squamate.
  5. Within lepidosaurs, geckos no longer nest with snakes, contra the LRT.
  6. Crocodiles nest with kiwis, as in the LRT, but it is still amazing that PAUP recovered this over such a large phylogenetic distance.
  7. Within aves, so few taxa are fossils in the LRT that the tree topology is very close to the original.
  8. Within mammals marsupials no longer nest between monotremes and placentals
  9. …and because of this carnivores split off next.
  10. Contra the LRT, hippos are derived from the cat and dog clade, all derived from weasels.
  11. Within mammals odontocetes no longer nest with tenrecs.
  12. Within mammals mysticetes nest with odontocetes, no longer nest with hippos.
  13. Contra the LRT, whales are derived from manatees and elephants.
Figure 1. Subset of the LRT focusing on Amniota (=Reptilia) with all fossil taxa deleted. Gephyrostegus, a Westphalian fossil is included as the outgroup.

Figure 1. Subset of the LRT focusing on Amniota (=Reptilia) with all fossil taxa deleted. Gephyrostegus, a Westphalian fossil is included as the outgroup.

BTW,
here are the results based on using the basal fish, Cheirolepis, as an outgroup:

    1. The caecilian, Dermophis, nests as the basalmost tetrapod.
    2. Followed by the frog and salamander.
    3. Squamates branch off next with legless lizards and burrowing snakes at a basalmost node. Terrestrial snakes are derived from burrowing snakes. Gekkos split next followed by varanids and skinks. Another clade begins with the tegu and Lacerta, followed by iguanids. Sphenodon nests between the horned lizards, Moloch and Phyrnosoma + the chameleon.
    4. Turtles split off next with the soft-shell turtle, Trionyx, at the base.
    5. One clade of mammals split off next with echidnas first, then elephant shrews and tenrecs, followed by a clade including the pangolin, seals and other basal carnivores. Cats and dogs split off next followed by hippos, then artiodactyls, perissodactyls, the hyrax, elephants, manatees, mysticetes and odontocetes.
    6. Another clade of mammals include edentates, followed by tree shrews and glires, followed by (colugos + bats) + primates, followed by another clade of basal carnivores, followed by marsupials.
    7. The final clade is Crocodylus + extant birds, which are not well resolved and split apart into two major clades with some subclades maintaining their topology while other clades split apart. So the archosaurs nest together.

This test emphasizes the need for the inclusion of fossil taxa in order to recover a gradual accumulation of traits at all nodes, which takes us closer to actual evolutionary patterns in deep time.

Misinterpreting Zhongornis

A few years ago
O’Connor and Sullivan 2014 took another look at a small bird-like theropod, Zhongornis, originally identified as a bird. They thought they saw “striking resemblances to both Oviraptorosauria and Scansoriopterygidae.” According to Wikipedia, “The authors reinterpreted Zhongornis as the sister taxon of scansoriopterygids, and further suggested that this clade (Zhongornis + Scansoriopterygidae) is the sister group of Oviraptorosauria.”

The original paper by Gao, et al. 2008
(O’Connor was a co-author) considered Zhongornis a bird, “the sister group to all pygostylia,” which is an invalid clade in the LRT. Several disparate clades developed pygostyles in the LRT.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in the majority of taxa.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in the majority of taxa.

By adding more relevant taxa,
in the large reptile tree (LRT, 1315 taxa) Zhongornis nested between Archaeopteryx (= Wellnhoferia) grandis and Confusciusornis (Fig. 1). Scansoriopterygids, in the LRT, are descendants of the Solnhofen bird, ‘Archaeopteryx‘ #12.

Figure 2. Zhongornis in situ.

Figure 2. Zhongornis in situ, skull reconstructiion, pes, manus and tail.

Zhongornis haoae (Gao et al. 2008; D2455; Early Cretaceous). Lack of fusion and bone texture indicate the Zhongornis holotype is a juvenile. The femoral heads and necks are not visible, perhaps not yet ossified. Even so, the wing feathers are well-develped, so the specimen is not a hatchling, but close to fledging, according to Gao et al.

Figure 3. Zhongornis pectorals as traced here and as traced by O'Connor and Sullivan (right).

Figure 3. Zhongornis pectorals as traced here and as traced by O’Connor and Sullivan (right).

The problem with the O’Connor and Sullivan paper was…
taxon exclusion. They did not test all Solnhofen birds, but considered them all Archaeopteryx and selected one to test. They did not realize that various Solnhofen birds are basal to ALL later bird clades, even those that gave up flying and grew to large to fly.

Figure 4. Zhongornis pelvic and tail area as traced here and as traced by O'Connor and Sullivan.

Figure 4. Zhongornis pelvic and tail area as traced here and as traced by O’Connor and Sullivan. The red bones are pubes. The green ones are ilia or impressions thereof.

We talk about elongate coracoids
when we talk about birds (Aves).

O’Connor and Sullivan 2014 report, “The coracoid is not well-preserved and is largely overlapped by other elements, making it difficult to confirm the original description (Gao et al., 2008) of this bone as strut-like; in DNHM D2456 it appears short, robust, and trapezoidal, a primitive morphology that characterizes oviraptorosaurs and scansoriopterygids, as well as dromaeosaurids, troodontids, Archaeopteryx and sapeornithiforms.”

In contrast
Zhongornis clearly has two elongate, barbell-shaped coracoids (Fig. 3), as in Confuciusornis.

In ReptileEvolution.com the coracoids of scansoriopterygids and Archaeopteryx have elongate coracoids. By contrast, Sapeornis and other sapeornithiforms have relatively short coracoids, reduced along with the forelimbs as the body size increased. This is sometimes called a reversal. Short coracoids can also be found in extant flightless birds.

Don’t judge or nest a taxon on just a few or a few dozen traits.
Always let the unbiased software place the taxon. To put limits on your taxon list.

References
Gao C-L, Chiappe LM, Meng Q-J, O’Connor JK, Wang X, Cheng X-D and Liu J-Y 2008. A new basal lineage of early Cretaceous birds from China and its implications on the evolution of the avian tail. Palaeontology 51(4):775-791.
O’Connor J-M and Sulivan C 2014.
Reinterpretation of the Early Cretaceous maniraptoran (Dinosauria: Theropoda) Zhongornis haoae as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs. Vertebrata PalAsiatica 52(1)1–9.

wiki/Changchengornis
wiki/Confuciusornis
wiki/Zhongornis

Anchiornis or not? And what about Pedopenna?

Xu et al. 2009
described a new genus, Anchiornis huxleyi IVPP V14378 (the holotype), along with LPM-B00169A, BMNHC PH828 as referred specimens), from the Late Jurassic of China. Two of these (Fig. 1) were added to the large reptile tree (LRT, 1315 taxa, subset Fig. 2). They nest in the LRT in the clade traditionally considered Troodontidae, between Velociraptor and Archaeopteryx. (Note other traditional troodontids, like Sinornithoides and Sauronithoides, do not nest in this pre-bird clade, but within the Haplocheirus clade.

Last year
a paper by Pei et al. 2017 described “new specimens of Anchiornis huxleyi. Two of these (Fig. 1) were also added to the LRT (subset in Fig. 2).

Figure 1. Four specimens attributed to Anchiornis. Two of these nest apart from two others (see figure 2).

Figure 1. Four specimens attributed to Anchiornis along with two others related to Anchiornis, but given different names. Two of these Anchiornis specimen nest apart from two others (see figure 2).

In the LRT
only two of the four tested Anchiornis specimens nested together (one was the holotype). That means the two other specimens were originally mislabeled. Moreover, a specimen attributed to a separate genus, Jinfengopteryx, nests with the holotype of Anchiornis and a referred specimen.

So do a few of the referred specimens need to be renamed? Perhaps so. Beyond the distinctly different skulls (Fig. 1), various aspects of the post-crania are also divergent.

Figure 2. Cladogram of taxa surrounding four specimens attributed to Anchiornis, which do not nest together in the LRT.

Figure 2. Cladogram of taxa surrounding four specimens attributed to Anchiornis, which do not nest together in the LRT. The holotype is the IVPP specimen in a darker tone and white arrowhead.

Pedopenna daohugouensis
(Xu and Zhang 2005; IVPP V 12721, Fig. 3) is a fossil theropod foot with long stiff feathers from the Middle or Late Jurassic, 164mya.

According to Wikipedeia
“Pedopenna was originally classified as a paravian, the group of maniraptoran dinosaurs that includes both deinonychosaurs and avialans (the lineage including modern birds), but some scientists have classified it as a true avialan more closely related to modern birds than to deinonychosaurs.”

Figure 1. Pedopenna in situ. Very little is known of this specimen.

Figure 3. Pedopenna in situ. The large alphanumerics are original. The color is added here. Very little is known of this specimen, but clearly long feathers arise from the metatarsus.

The first step
in figuring out what Pedopenna is, is to create a clear reconstruction (Fig. 4). Only then will we be able to score the pedal elements in the LRT.

Figure 2. Pedopenna in situ and reconstructed using DGS techniques.

Figure 4. Pedopenna in situ and reconstructed using DGS techniques.

Surprisingly,
and despite the relatively few pedal traits, the LRT is able to nest Pedopenna between and among the several Anchiornis specimens (Fig. 5). Specifically it nests between the holotype IVPP specimen and the LPM specimen. So is Pedopenna really Anchiornis? Or do all these taxa, other than the holotype, need their own generic names?

Figure 3. Where feathers on the foot are preserved on the LRT.

Figure 5. Where feathers on the foot are preserved on the LRT.

Earlier we looked at the development of foot feathers to aid in stability in pre-birds and other bird-like taxa just learning to flap and fly, convergent with uropatagia in pre-volant pterosaur ancestors.

A note to Anchiornis workers:
Try to test all your specimens in a phylogenetic analysis for confirmation, refutation or modification of the above recovery. Pei et al. considered all the specimens conspecific. They are not conspecific, as one look at their skulls alone (Fig. 1) will tell the casual observer.

References
Pei R, Li Q-G, Meng Q-J, Norell MA and Gao K-Q 2017. New specimens of Anchiornis huxleyi (Theropoda: Paraves) from the Late Jurassic of Northeastern China. Bulletin of the American Museum of Natural History 411:66pp.
Xu X, Zhao Q, Norell M, Sullivan C, Hone D, Erickson G, Wang X, Han F and Guo Y 2009. A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin. Chinese Science Bulletin 54 (3): 430–435. doi:10.1007/s11434-009-0009-6
Xu X and Zhang F 2005. A new maniraptoran dinosaur from China with long feathers on the metatarsus. Naturwissenschaften. 92 (4): 173–177. doi:10.1007/s00114-004-0604-y.

wiki/Pedopenna