More evidence that black vultures are ugly pigeons

There’s at least one pigeon larger than a vulture.
It’s Goura, the Victorian crowned pigeon (Fig.s 1, 2). Goura is  the same size or larger than Coragyps, the black vulture (Fig. 1) and these two nest together in the large reptile tree (LRT, 1224 taxa). Smaller pigeons, like Columba and Caloenas nest together, next to Goura + Coragyps.

Figure 1. The largest pigeon, Goura, nests with Coragyps the black vulture, not with Columba, the rock pigeon.

Figure 1. The largest pigeon, Goura, nests with Coragyps the black vulture, not with Columba, the rock pigeon.

Goura cristata (Pallas 1764; Stephens 1819; Figs. 1, 2) is the extant Western crowned pigeon. It is restricted to New Guinea. It eats fruits and seeds.

Figure 2. Victorian crowned pigeon (genus: Goura) skeleton. Compare to figure 3.

Figure 2. Victorian crowned pigeon (genus: Goura) skeleton. This taxon nests with the black vulture, Coragyps, in the LRT. Compare to figure 3.

Coragyps atratus (LaMout 1853; 56-74 cm in length, 1.5m wingspread; Fig. 3) is the extant black vulture and a sister to Goura (Fig. 2). Both were derived from the more primitive giant petrel Macronectes. There are not very many differences between these two skeletons, perhaps one of the reasons bird workers have given up analyzing bone shapes and proportions and have taken to trusting DNA analyses.

Remember
black vultures are New World vultures. They are not related to Old World vultures in the LRT, or in any other analysis. At present this is the only New World vulture in the LRT. Old world vultures, like Torgos, nest with birds of prey.

Figure 3. When vultures drift north and start finding fish attractive they evolve into auks and puffins.

Figure 3. Skeleton of Coragyps, the black vulture. Compare to figure 2.

Beautiful as adults…
not so beautiful as chicks, Goura hatchlings look more like black vultures before they get their silky blue adult plumage. This is neotony at work once again. We’re going to look more and more at neotonous sisters and compare them to short-legged, short rostrum chicks of longer-legged, longer-beaked taxa. This is not an isolated incidence.

FIgure 4. Is it any wonder that the Goura chick is so colorless and ugly, given its relation of Coragyps, the black vulture?

FIgure 4.The Goura chick is so colorless and ugly. This makes sense given its relation of Coragyps, the black vulture. And now we know which came first, the pigeon or the vulture. The big pigeon came first, followed by smaller and smaller taxa. 

References
Gmelin JF 1789. Caroli a Linné … Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, Cum Characteribus, Differentiis, Synonymis, Locis. Editio Decima Tertia, Aucta, Reformata/ cura Jo. Frid. Gmelin. Volume 1, part 3. Lipsiae: Impensis Georg. Emanuel. Beer.
Gray GR 1840. List of Gen. B:59
LeMaout JEM 1853. Les trois regnes de la nature. Regne animal. Histoire naturalle des oiseaux, suivant la classification de M. Isidore Geoffroy-Saint-Hillaire, avec l’indication de leurs moeurs et de leurs rapports avec les arts, le commerce et l’agriculture. Par Emm. Le Maout. L. Curmer. Paris 425 pp.
Pallas PS 1764. Adumbratiunculae avium variorum praecedenti Elencho inserlarum, sed quae in Systemate Naturae Illustr. Linnaei nondum extant. Pp. 1-7 in Vosmaer 1764.
Vieillot LJP 1809. Histoire naturelle des oiseaux de l’Amérique Septentrionale

wiki/Columba
wiki/Nicobar_pigeon
wiki/Coragyps atratus
wiki/Goura

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What is a limpkin? (genus: Aramus)

Figure 1. The limpkin (Aramus guarauna) is a basal member of the x family.

Figure 1. The limpkin (Aramus guarauna) is a long-legged, wading basal member of the x family.

Aramus guarauna (Linneaus 1766) is the extant limpkin. It is often considerd transitional between rails and cranes. In the large reptile tree (1121 taxa) the limpkin nests basal to seagulls and hummingbirds, plovers and crowned cranes, common cranes and stilts, terns and loons, kingfishers and jabirus, murres and penguins.

Figure 1. Skeleton of the limp kin (Aramus), traditionally nests within the crane and rail order Gruiformes.

Figure 2. Skeleton of the limpkin (Aramus), traditionally nests within the crane and rail order Gruiformes. In the LRT rails are not closely related, so Gruiformes should no longer include rails.

Extant limpkins eat snails.
Primitive limpkins like Aramournis  probably had a more diverse diet. It is known from a distal tarsus.

Traditional rails
like the corn crake (Crex) and the coot (Fulica) are much more basal birds that give rise to chickens, sparrows and parrots. Adding Rallus, the Virginia rail, to the LRT nests it between Aramus and the rest of the clade, which, phylogenetically makes hummingbirds, terns and penguins variations on the rail theme and Rallus at least a Middle Cretaceous taxon radiation.

Figure 4. Virginia rail alongside the rail clade in the LRT.

Figure 4. Virginia rail alongside the rail clade in the LRT.

Congeneric specimens of Aramus
are found in the Miocene, but more derived penguins are found in the Paleocene, pointing to a mid-Cretaceous radiation of this clade.

Limpkins are derived from Cretaceous sisters to
hamerkops (Scopus) and stone curlews (Burhinus), both long-legged taxa. By the evidence shown in the crown bird subset of the LRT (Fig. 4), long legs, like those shown by Aramus, the limpkin, are basal traits. The retention of hatchling short legs occurred several times by convergence, sometimes during the Cretaceous. See the earlier post on post K-T non-arboreal birds. 

Figure 4. Subset of the LRT focusing on the crown bird clade. Brown taxa are all long-legged. Neotony produces the smaller, shorter-legged, arboreal taxa.

Figure 4. Subset of the LRT focusing on the crown bird clade. Brown taxa are all long-legged. Neotony produces the smaller, shorter-legged, arboreal taxa.

References
Linneaus C von 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. pp. 1–532. Holmiæ. (Salvius)

wiki/Aramus_limpkin

Bird, pterosaur, dinosaur simplified chronology

Following the earlier post on non-arboreal post K-T boundary birds…

…this one pretty much speaks for itself.
Here (Fig. 1) is a chronology, very much simplified, of birds, pterosaurs and dinosaurs according to the LRT.

Figure 1. Mesozoic chronology of bird, dinosaur and pterosaur clades.

Figure 1. Mesozoic chronology of bird, dinosaur and pterosaur clades based on taxa in the LRT.

If you’re curious about any of the taxa,
in the chronology, simply use Keywords to locate them.

Balearica: a unique ‘crane’ with skull bumps

This came with some surprise.
The gray-crowned crane (Balearica regulorum) has beautiful plumage, but under the skin this bird has twin skull bumps on the posterior frontals (Fig. 1).

Figure 1. Balearica regulorum in vivo and two skulls (showing individual variation).

Figure 1. Balearica regulorum in vivo and two skulls (showing individual variation).

Distinct from most cranes,
Balearica has a short rostrum (derived from Charadrius, a neotonous crane with juvenile proportions and size as an adult, based on sister taxa in the large reptile tree, LRT, 1221).

Figure 2. Balearica compared to its sister in the LRT, Charadrius, the plover/kildeer.

Figure 2. Balearica compared to its sister in the LRT, Charadrius, the plover/kildeer.

Balearica regulorum (= Ardea regulorum, Anthropoides regularum, Bennett 1834; extant; 1m tall, 2m wingspan) is the gray crowned crane, and a member of the Gruidae/Gruiformes. In the LRT Balearica is most closely related to the neotenous plovers and kildeers (genus: Charadrius,Fig. 2) and shares with them, a short bill. Twin bumps appear on the posterior frontal. Only four phalanges appear on pedal digit 4, which is as long as pedal digit 3. This trait pops up occasionally, apparently autapomorphic each time.

Using DNA
Prum 2015 nested Balearica with another crane, Grus, the limp kin, Aramus, and the trumpeter, Psophia, which is more closely related to roadrunners and cuckoos in the LRT. Prum 2015 nested Charadrius with Burhinus, close to nestings in the LRT, far from Balearica.

Olson 1985 reports
“From North America there is now a considerable representation of small to medium-sized cranes that are closely related to the modern African crowned cranes of the genus Balearica.” That makes sense with so many plovers and killdeer in North America. I see them all the time on St. Louis parking lots. Never thought they were related the one of the most beautiful birds on the African savanna.

References
Bennett ET 1834. On two new species of Crowned Cranes [Anthropoidea, Vivil.] from Africa. Zoological Society Proceedings pt. 1, 1833:118–119. Oken, Isis, 1835, col. 549–550.
Olson S 1985. The fossil record of birds pp. 80–218 in Farner DS, King JR and Parkes KC (eds.) Avian Biology 8: chapter 2, Academic Press, Inc.
Prum et al. (6 co-authors) 2015. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526:569–573. online

wiki/Balearica
wiki/Charadrius

Post K-T event birds were all non-arboreal…

…whether tested using DNA or skeletal traits…

Field et al. 2018
used DNA to produce a cladogram of extant birds to determine that basal taxa were all non-arboreal. Earlier the large reptile tree (LRT, 1121 taxa) came to the same conclusion using trait analysis and fossils (Figs. 1, 2). The only difference is the Field team determined that the crown bird radiation was post-Cretaceous. The LRT recovered a crown bird radiation in the post-Jurassic and post-Cretaceous birds were also non-arboreal (Fig. 1, 2). An earlier radiation explains the Paleocene appearance of very derived fossil penguins and the Early Cretaceous appearance of the fossil chicken, Eogranivora.

Figure 2. Basal bird phylogeny based on the LRT (morphology)

Figure 1. Basal bird phylogeny based on the LRT (morphology.

Unfortunately
Field et al. also recovered flamingos with grebes, chickens with ducks, and many other physical trait mismatches, like those in Prum et al. 2015. Such mismatches are ignored by DNA workers.

Figure 1. Click to enlarge. Duck origins recovered by the LRT. Duck descendants were long-legged walkers and later waders.

Figure 2. Click to enlarge. Duck origins recovered by the LRT. Duck descendants were long-legged walkers and later waders.

From the Field et al. 2018 abstract:
“We suggest that ecological filtering due to the temporary loss of significant plant cover across the K-Pg boundary selected against any flying dinosaurs (Avialae) committed to arboreal ecologies, resulting in a predominantly non-arboreal post-extinction neornithine avifauna composed of total-clade Palaeognathae, Galloanserae, and terrestrial total-clade Neoaves that rapidly diversified into the broad range of avian ecologies familiar today. The explanation proposed here provides a unifying hypothesis for the K-Pg-associated mass extinction of arboreal stem birds, as well as for the post-K-Pg radiation of arboreal crown birds.”

Unfortunately
the loss of an arboreal habitat due to world-wide fires does not explain the disappearance of the Cretaceous toothed sea birds, Ichthyornis and Hesperornis. Other explanations must be invoked.

Figure 1. More taxa, updated tree, new clade names.

Figure 3. More fossil taxa, updated tree, new clade names. Note the derived position of the penguin Aptenodytes, with with fossil penguins in the Paleocene.

The mechanism for crown birds invading trees
appears to have been neotony, with chick-sized adults with short legs and short necks arising from larger, long-legged, long-necked predecessors (e.g. Passer the sparrow and Opisthocomus, the hoatzin, arising  from Gallus, the chicken). Notably the hatchlings of arboreal taxa are typically not precocial, hatching out a more helpless stage in their ontogeny and growing to fledgling size rapidly.

Field et al. correctly report,
“…virtually the entirety of the avian crown-group fossil record is restricted to sediments of Cenozoic age, and the earliest well-supported crown bird fossil is scarcely older than the end-Cretaceous, at approximately 67 Ma.” True. This is one of the unresolved mysteries of paleontology, only now starting to crack with discoveries like Eogranivora, the early Cretaceous chicken, and the nesting of Cretaceous toothed birds between paleognaths and neognaths (Fig. 3), something the Field analysis was not able to recover.

Figure 1. Megapodius is the extant bird nesting at the base of all neognathae (all living birds except ratites).

Figure 4. Megapodius is the extant bird nesting at the base of all neognathae (all living birds except ratites). Post K-T event birds look more or less like this one. One might ask, if all the adults were killed, would the precocious hatchlings, hidden beneath thick mounds, form the first generation of K-T event survivors?


One might ask,

if all adult birds worldwide were killed on exposure to oven-like temperatures and subsequent lack of trees, would the buried, precocious hatchlings of mound-builders, like Megapodius (Fig. 4), create the first generation of K-T event bird survivors? If so, perhaps the tinamou ancestors of modern tinamous and ratites were likewise mound builders. Currently tinamous and ratites are not mound-builders.

Basal members of all bird clades in the LRT
appear to have survived the K-T event, based on the Paleocene presence of fossil penguins, like Waimanu (Fig. 5). Overlooked by Field et al., basal members of all the major crown bird clades in the LRT (Fig. 3) are all non-arboreal, long-legged, wading taxa (Fig. 2), that do not nest in trees.

Figure 1. The world at the K-T boundary, 65 mya and the distribution of Paleocene birds.

Figure 5. The world at the K-T boundary, 65 mya and the distribution of Paleocene birds.

References
Field  DJ et al. (7 co-authors) 2018. Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction. Current Biology (advance online publication) DOI: https://doi.org/10.1016/j.cub.2018.04.062

The black skimmer (Rynchops niger) enters the LRT

And it nests with
the extinct great auk (Pinguinus) in the large reptile tree (LRT, 1217 taxa). No wonder it seems so different than other living birds! It is.

Figure 1. Black skimmer (genus: Rynchops) in vivo.

Figure 1. Black skimmer (genus: Rynchops) in vivo.

These, in turn
are close to the puffin (Fratercula), which also has large keratinous extensions of the rostrum and mandible, and not one, but two mandibular fenestrae.

Figure 2. Skull of the the black skimmer (Rynchops niger) with bones colorized. Note the large keratinous extension extending the mandible.

Figure 2. Skull of the the black skimmer (Rynchops niger) with bones colorized. Note the large keratinous extension extending the mandible. Note the slight differences in the two presented skulls.

Rynchops niger (Linneaus 1758; up to 50 cm in length) is the extant black skimmer, famous for having a longer lower bill than upper. It flies low on still waters to skim for fish near the surface. Close relatives include the auk, Pinguinus and the puffin, Fratercula, all derived from skuas and petrels.

Figure 2. Pinguinus the great auk skull.

Figure 3. Pinguinus the great auk skull. This flightless extinct bird nests closest to the black skimmer in the LRT. Note the two mandibular fenestra, The curved and expanded premaxilla that extends no further posteriorly than the naris, the pinched rostrum,  the tiny ascending process of the retroarticular process, the quadratojugal that extends to the antorbital fenestra,

Prum et al. 2015
nested Rynchops with the black-headed gull (Chroicocephalus) using DNA data. They did not test the extinct Pinguinius. In the LRT, the black-headed gull nests with another clade of wading birds, beginning with the limpkin, Aramus.

Figure 1. Chroicocephalus, the black-headed sea gull in vivo and as a skeleton.

Figure 4. Chroicocephalus, the black-headed sea gull in vivo and as a skeleton. This taxon nests with hummingbirds, both derived from stilts and other wading birds like the limpikin (Aramus).

 

 

References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Atlantic_puffin
wiki/Great_auk
wiki/Black_skimmer

 

The assembly of the avian body plan (Cau 2018) pt. 3 of 3

Yesterday and the day before we looked at parts 1 and 2 of the Cau 2018 tree topology of theropods leading to birds (Fig. 3). Today: part 3 of 3.

Node 19. Maniraptora: (Alvarezsauroidea + Pennaraptora) Here’s where the second Compsognathus (CNJ79) would affect the Cau topology. The basal member of Maniraptora in the Cau tree is Jianchangosaurus, which has a toothless premaxillla and nests with therizinosaurs traditionally and in the LRT (Fig. 5). You don’t want a toothless premaxilla at this basal node because most succeeding taxa have premaxillary teeth. In the LRT, Jianchangosaurus is a derived therizinosaur, close to a surprise tiny therizinosaur with long forelimbs and a trenchant pedal digit 2, Rahonavis. That may change or be confirmed with more complete specimens.

The LRT agrees with Cau in nesting Shuvuuia with Haplocheirus.

Figure 1. Jianchangosaurus nests at the base of the Maniraptora in Cau 2018, but with therizinosaurs in the LRT.

Figure 1. Jianchangosaurus nests at the base of the Maniraptora in Cau 2018, but with therizinosaurs in the LRT, where it nests with Rahonavis.

Figure 2. Rahonavis nests in the LRT as a tiny derived therizinosaur based on the few bones currently known.

Figure 2. Rahonavis nests in the LRT as a tiny derived therizinosaur based on the few bones currently known.

Node 20. Pennaraptora (Oviraptorosauria + Paraves) The Cau study and the LRT agree that Caudipteryx and Khaan nest together. Lacking from the Cau study, Limusaurus (Fig. 1) nests as a basal oviraptorid in the LRT. In turn the Cau study includes taxa not listed in the LRT.

Node 21. Paraves: Distinct from the Cau tree, the LRT nests Microraptor with Ornitholestes and apart from Deinonychus and Velociraptor. The LRT nests Fukuiraptor with Zhenyuanlong with tyrannosaurs. The Cau study does not include Zhenyuanlong. 

Figure 1. The origin of birds cladogram according to Cau 2018. Taxon exclusion forces a mixup of basal taxa.

Figure 3. The origin of birds cladogram according to Cau 2018. Taxon exclusion forces a mixup of basal taxa.

Node 22. Averaptora: In the Cau study Sinovenator nests with Jinfengopteryx and Mei. In the LRT, Jinfengopteryx (Fig. 4) nests as a basal troodontid, derived from a sister to Velociraptor and Haplocheirus. Sinovenator nests closer to birds. Mei nests within birds (Scansoriopterygidae). Yi and Epidexpteryx are also scansoriopterygids. Cau nests them basal to Archaeopteryx.

 Jinfengopteryx, a basal troodontid in both studies.

FIgure 4. Jinfengopteryx, a basal troodontid in both studies. Think of this taxon like a neotonous velociraptor, leading to all troodontids including (with further neotony) birds. Note the resemblance to Solnhofen birds.

Employing only one Archaeopteryx in the Cau study
overlooks the variety in Solnhofen birds recovered by the LRT. When this is repaired with more taxa, let’s see what happens when more Solnhofen birds are added (Fig. 5):

Figure 1. Cladogram subset of the LRT focusing on Theropoda.

Figure 4. Cladogram subset of the LRT focusing on Theropoda, including extant birds.

As we learned
earlier, no two Solnhofen birds are identical. In the LRT they are distinct enough to nest in several basal bird clades. This was completely missed by Cau and most other bird workers.

Missing from the Cau taxon list
are any living birds. In the LRT, the toothed Cretaceous birds nest between paleognaths and neognaths, so that branch was missed.

Sometimes
taxon exclusion adversely affects tree topologies. Start with a wide gamut analysis (Fig. 5) that sets limits on the more focused study that you want to look at.

References
Cau A 2018. The assembly of the avian body plan: a 160-million-year long process. Invited Paper, Bollettino della Societa Paleontologica Italiana 57(1):1–25.