The curassow (genus: Mitu/Crax) another chicken cousin

Mitu tuberosum aka Crax turberosa (Linneaus 1758, Spix 1825; 85 cm) is the extant razor-billed curassow, a pheasant-like galliform from the Amazon. Only two eggs are laid per year. Precocious young are feathered and mobile after hatching. Omnivorous. Sexes are similar.

Figure 1. Crax tuberosa skeleton and invivo. This basal neognath bird prefers to walk than fly.

Figure 1. The curassow, Mitu tuberosum/Crax tuberosa, skeleton and invivo. This basal neognath bird prefers to walk than fly.

In the large reptile tree (LRT, 1127 taxa) the curassow (genus Mitu or Crax) nests with the Early Cretaceous bird, Eogranivora, and this clade nests with the chicken (Gallus) and the peafowl (Pavo).

Figure 1. Crax tuberosa skull in three views.

Figure 2. The curassow, Crax tuberosa, skull in three views. Note the slender postorbital (yellow) descending from the robust postfrontal (orange).

The helmeted curassow (genus: Pauxi pauxi) has a casque convergent with the cassowary (Casuarius).

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.
von Spix JBR 1825. Avium species novae, quas in itinere per Brasiliam annis MDCCXVII – MDCCCXX […] collegit et descripsit. Franc. Seraph. Hübschmann, Monachii [Munich], 1, [VII], 90 pp., 91 pls.

wiki/Crax
wiki/Mitu
wiki/Razor-billed_curassow

Advertisements

Where does the frigate bird nest?

For a blog focused on pterosaurs
it sure took a long time to take a look at the extant frigate bird (Figs. 1-3; genus: Fregata), a modern analog for many of the sea-faring clades of pterosaurs in terms of wing shape (long span, short chord) and gliding ability (see below).

FIgure 1. Fregata in flight.

FIgure 1. Fregata in flight. Note the narrow-chord wing membrane, as in all pterosaurs.

Between pelicans and cormorants 
In the large reptile tree (LRT, 1227 taxa) the frigate bird nests between the clade Pelecanus + Balaeniceps (the shoebill) and Phalacrocorax (the cormorant). The shoebill has the longest legs in the clade, so it is the most primitive member. Most studies, including the LRT and DNA analyses, associate frigate birds with pelicans, skuas and petrels, but some link frigate birds with a larger list including herons, ibises, spoonbills, hamerkops, penguins, loons, gannets, and cormorants. Why can’t DNA be more specific? That’s a wide gamut of taxa. The LRT is specific and fully resolved.

FIgure 2. Fregata skull with a closeup of the tiny jugal.

FIgure 2. Fregata skull with a closeup of the tiny jugal.

Interesting that frigate birds don’t like to get wet
while their sisters, cormorants dive for food, but then have to stand with wings dripping while drying out. Distinct from ducks, cormorant feathers don’t shed water with an oily coat.

Figure 4. Skeleton of Fregata, the frigate bird. Note the long bill, long neck and long antebrachium, perhaps the closest living analog to Cretaceous ornithocheirid pterosaurs.

Figure 3. Skeleton of Fregata, the frigate bird. Note the long bill, long neck and long antebrachium, perhaps the closest living analog to Cretaceous ornithocheirid and pteranodontid pterosaurs (Fig. 5). Consider this a shoebill stork and/or pelican with a slender bill and very short legs and you will be close to its phylogenetic grade.

Fregata magnificens (Lacépède, 1799; up to 56 cm long) inflates its throat sac with air, like a balloon, to display its bright red color (distinct from the pelican throat sac, which fills with water and prey). According to Wikipedia, “frigatebirds spend most of the day in flight hunting for food, and roost on trees or cliffs at night. The duration of parental care is among the longest of any bird species; frigatebirds are only able to breed every other year. Fossils date back to the Eocene, 50 mya.” 

Figure 2. Cearadactylus, Anhanguera and Pteranodon compared. The inset compares the humerus of Anhanguera and Pteranodon.

Figure 4. Cearadactylus, Anhanguera and Pteranodon compared. The inset compares the humerus of Anhanguera and Pteranodon. Compare proportions to the skeleton of Fregata. Look at those long wing tips, completely different from flightless pterosaurs, including large to giant azhdarchids. Most workers consider these taxa to be closely related, but the LRT does not confirm that.

Tested frigate birds
(Huey and Deutsch 2016) stayed aloft for two months without ever touching the ground riding cumulus thermals up to 6500 feet above sea level. 

Like ornithocheirid and pteranodontid pterosaurs
the torso is small and the wing has a narrow chord and a wide span in Fregata. This is also like modern man-made gliders, and unlike the proportions found in large to giant azhdarchids, which could not fly at all, contra traditional thinking, based on their relatively short distal wing finger phalanges (like those of small flightless pterosaurs).

References
Huey RB and Deutsch C 2016. How frigate birds soar around the doldrums. Science 353 (6294):26–27.
Lacépède BGÉ de 1799. Discours d’ouverture et de clôture du cours d’histoire naturelle : donné dans le Muséum national d’Histoire naturelle, l’an VII de la République, et tableaux méthodiques des mammifères et des oiseaux, Paris.

wiki/Frigatebird

The origin of hummingbirds from sea gulls, part 2

I was looking for a small seagull,
as a transitional taxon leading toward hummingbirds, but I could not find one better than Eocypelus (Fig. 1) from the Eocene. Then I looked for a giant hummingbird. That’s when I found Patagona gigas (Fig. 1).

Earlier, with 100 fewer taxa,
the large reptile tree (LRT, 1227 taxa) nested hummingbirds with Chroicocephalus, the extant seagull (Fig. 1) here.

Figure 1. The origin of hummingbirds from the sea gull, Chroicocephalus.

Figure 1. The origin of hummingbirds from the sea gull, Chroicocephalus. Patagona is a giant hummingbird. Archilochus is a mid-sized ruby-throated hummingbird. Mellisuga is the bee hummingbird, the smallest adult bird, theropod and dinosaur. Patagona skull from Digimorph.org and used with permission.

Phylogenetic miniaturization
(also called the Lilliput effect), is a key driver in the genesis of new clades. This neotonous trend also brought us hummingbirds… and tiny hummingbirds, including the smallest of all birds, the bee hummingbird (genus: Mellisuga, Fig. 1). Eocypselus more clearly represents phylogenetic miniaturization due to its short rostrum. Thereafter the descendants of Eocypselus leading toward hummingbirds developed a longer rostrum, like that of Patagona. Otherwise their skulls are about the same size. Perhaps this was the transition point leading to nectar feeding, rather than sea dipping.

Figure 2. Patagona gigas, the giant hummingbird.

Figure 2. Patagona gigas, the giant hummingbird.

Patagona has a relatively slow wing beat
while hovering, only 15 wing beats per second. According to Wikipedia, “Hummingbird muscle fibres are filled with mitochondria (50% by volume) enabling high frequency wing beats to be sustained over extended periods using oxidative energy.” The range of this genus extends along the Pacific side of the Andes from Ecuador to mid-Chile.

The Andean gull (Chroicocephalus serranus) has a similar range and, unusual for a gull, breeds inland in mountain areas and can be found around rivers, lakes, marshes and pasturelands. It is an insectivore, sometimes aerially and otherwise on fields and grasslands. Distinct from hummingbirds, the Andean gull swims like a duck. But hummingbirds do like bird baths.

References

wiki/Hummingbird
wiki/Archilochus
wki/Eocypselus_rowei
wiki/Patagona
wiki/Mellisuga
wiki/Black-headed_gull

Largest birds and pterosaurs to scale (finally!)

Question: Could the largest azhdarchids fly?
Tradition says: Yes! Most pterosaur workers say: Yes! Flying azhdarchid models say: Yes!

Heresy:
We looked at that question earlier and came to another conclusion based on comparable vestigial wingtip phalanges in flightless pterosaurs. Today there’s more to consider.

Let’s take another look at that same problem,
this time comparing the largest flying bird to the largest flying pterosaurs, and the largest non-flying bird to a giant pterosaur (Fig. 1). Since the largest flying birds and pterosaurs had the longest wing/neck and wing/torso ratios, the reduction of wing span/neck length points toward flightlessness—if analogous.

As reported yesterday,
lacking the ability to fly removes the constraints for multiple increases in size. We know of no pterosaurs that had vestigial wings, only vestigial distal wing phalanges. Three of the four flightless pterosaurs we looked at earlier were pterodactyloid-grade quadrupeds, so their free fingers had to contact the substrate. Moreover, all flightless pterosaurs could still flap vigorously, whether to ward off threats by display and/or increase thrust while fleeing.

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale. Are large soaring birds analogs to large flying pterosaurs. If so, then are large non-flying birds analogs to large non-flying pterosaurs. Does giving up flight enable giantism in birds and pterosaurs?

While recognizing obvious differences
between the largest pterosaurs and birds, which are more alike?

On the one hand
we have pterosaurs and birds with shorter necks, shorter legs and longer wings.

On the other hand
we have a pterosaur and a bird with a longer neck, longer legs and a relatively shorter wing (compared to those of volant pterosaurs). Is it really as simple as that?

Or did I cherry-pick taxa?

Figure 2. Azhdarchids are stork-like waders, so Ciconia, the stork, is a good analog. It is notably smaller than the smallest known Quetzalcoatlus.

Figure 2. Azhdarchids are stork-like waders, so Ciconia, the stork, is a good analog. It is notably smaller than the smallest known Quetzalcoatlus, about the size of flying azhdarchids.

Azhdarchids are often compared to storks.
And they do have similar proportions (Fig. 2). But all storks fly and some of the largest (e.g. Ciconia) are only half as tall as the smallest Quetzalcoatlus sp. We know of no giant storks. Even so, at half as tall, the legs of Ciconia were equal in length to the larger Q. sp, the torso was similar in size, and the neck and skull were only half as long. All this would appear to make azhdarchids top heavy relative to the volant stork (Fig. 3), despite a longer wing span, even with reduced distal elements.

Figure 3. Q. northropi and Q. sp. compared to Ciconia, the stork, and Pelagornis, the extinct gannet, to scale. That long neck and large skull of Quetzalcoatlus would appear to make it top heavy relative to the volant stork, despite the longer wingspan. Pteranodon and other flying pterosaurs do not have such a large skull at the end of such a long neck (Fig. 1). The longer wings of pelagornis show what is typical for a giant volant tetrapod, and Q. sp. comes up short in comparison.

Figure 3. Q. northropi and Q. sp. compared to Ciconia, the stork, and Pelagornis, the extinct albatross/gannet, to scale. That long neck and large skull of Quetzalcoatlus would appear to make it top heavy relative to the volant stork and gannet, despite the longer wingspan compared to the stork. Pteranodon and other flying pterosaurs do not have such a large skull at the end of such a long neck (Fig. 1). The longer wings of Pelagornis show what is typical for a giant volant wide-ranging tetrapod, and Q. sp. comes up short in comparison.

What about those wings?
Compared to the stork, Q sp. had longer wings. Compared to albatrosses and pterosaurs, Q. sp. had shorter wings. In any case, that long neck is strikingly different in azhdarchids. Such a long lever arm had to affect the center of balance (Fig 3 red line).

Figure 3. Quetzalcoatlus model ornithopter by Paul Macready getting walked to its take-off point.

Figure 4. Quetzalcoatlus model ornithopter by Paul Macready getting walked to its take-off point. The wing chord extends to the posterior pelvis, which is invalid. The demonstrated wing chord is shown in figure 3.

What about that mechanical flying Q. sp?
Paul Macready built and flew a gliding Q. sp., (Fig. 4) not a Q. northropi. It did not have a long enough neck or large enough skull. As it was, it was well-engineered and all the mechanics in the torso were unlikely duplicated in the Late Cretaceous taxon.

Figure 5. The Macready flying model compared to Q. sp. Perhaps it has always been overlooked that the neck proportions were changed and heavy mechanical motors and batteries filled the torso.

Figure 5. The Macready flying model compared to Q. sp. Perhaps it has always been overlooked that the neck proportions were changed and heavy mechanical motors and batteries filled the torso. The hind limbs are unnaturally tucked in in the model, following Kevin Padian’s invalidated view that pterosaurs were close to dinosaurs.

The question(s) comes down to:
If large soaring birds are analogs to large flying pterosaurs, then are the largest non-flying birds analogs to the largest pterosaurs? Does giving up flight enable and promote gigantism in birds AND pterosaurs?

At present, the evidence says: yes.

However, it’s not that giant pterosaurs were “too big to fly”.
Here’s the working hypothesis: Smaller pterosaurs that stopped flying were then able to grow much bigger, with less constraint for maintaining a center of balance at the shoulders.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure  6. Quetzalcoatlus running like a lizard prior to takeoff. Leaning forward while running fast is what humans do to. Perhaps the neck was held more erect, like an ostrich or giraffe, back in the Late Cretaceous.

Not sure why it took so long
to put large pterosaurs and birds together. This should have been posted years ago.

 

Tiny Pumiliornis: enigma no longer

Pumiliornis tesellatus
is a wren-sized (shown larger than actual size) Messel pit bird that was originally (Mayr 1999) considered an enigma and later (Mayr 2008) allied with cuckoos. In the large reptile tree (LRT, 1225 taxa) tiny Pumiliornis nests with Platalea, the spoonbill (Fig. 2) as a phylogenetic miniature, close to, but not quite related to the parallel, short-legged genesis of ducks and geese.

Presbyornis, currently at the base of ducks, still has long legs and a long neck. More derived taxa in the duck branch lose their long legs, although some, like the swan and goose, retain a long neck.

Figure 1. Pumiliornis is a phylogenetic miniature related to the spoonbill, Platalea, at the genesis of ducks.

Figure 1. Pumiliornis is a phylogenetic miniature related to the spoonbill, Platalea, at the genesis of ducks.

Pumiliornis tessellatus (Mayr 1999, 2008; 6cm long; middle Eocene). This wren-sized relative to spoonbills and ancestor to ducks has a spatulate beak tip. This is a neotonous form of the long-legged spoonbill with juvenile size and proporitons representing the genesis of a new clade. This fossil contains fossil grains in the cloacal area (white box). Note that no webbing is preserved between the toes. Spoonbills also lack webbed toes.

Figure 1. The roseate spoonbill (genus: Platalea) in vivo. Traditionally spoonbills and storks have been nested together. Here it nests between storks and ducks.

Figure 2. The roseate spoonbill (genus: Platalea) in vivo. Traditionally spoonbills and storks have been nested together. Here the spoonbill nests between the ibis, Threskiornis, and ducks.

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
Mayr G 1999. Pumiliornis tessellatus n. gen. n. sp., a new enigmatic bird from the Middle Eocene of Grube Messel (Hessen, Germany). Courier Forschungsinstitut Senckenberg, 216: 31–73, Frankfurt a.M. 1999.
Mayr G 2008. Pumiliornis tessellatus MAYR, 1999 revisited – new data on the osteology and possible phylogenetic affinities of an enigmatic Middle Eocene bird. Palfontologische Zeitschrift. 82/3: 247–253.

wiki/Platalea
wiki/Pumiliornis

Rhea: Looks like an ostrich. Nests with a cassowary in the LRT.

Nesting Rhea with Casuarius agrees with prior analyses.

Figure 1. Rhea skull shares more traits with Casuarius, the cassowary.

Figure 1. Rhea skull shares more traits with Casuarius, the cassowary. Note the confluent naris, antorbital fenestra, orbit and temporal fenestrae.

 

Rhea americana (extant) is the largest rhea of South America. The juvenile has a large thumb claw and unfused fingers that fuse with maturity. Essentially this is a giant tinamou.

Figure 2. The cassowary skull shows the mesethmoid (yellow green) is greatly expanded from its original flat appearance in Rhea.

Figure 2. The cassowary skull shows the mesethmoid (yellow green) is greatly expanded from its original flat appearance in Rhea (Fig. 1).

Casuarius casuarius (Brisson 1760; up to 2m tall) The extant cassowary is one of the few birds with a bony crest or casque on its head. Derived from a tinamou like Rhynchotus, this flightless omnivore feeds mainly on fruit, shoots and small seeds. The crest shape variws with the individual. Females are larger and more brightly colored. The manus is a fused (undifferentiated) vestige.

Figure 2. Rhea skeleton with enlarged manus and pes.

Figure 2. Rhea skeleton with enlarged manus and pes. The inset shows an unfused manus, fused in the adult.

 

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/Rhynchotus
wiki/Cassowary
wiki/Elegant_crested_tinamou

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