The budgie has a pseudo-jugal!

Figure 1. The number 3 pet in the world (after cats and dogs) is the Budgerigar.

Figure 1. The number 3 pet in the world (after cats and dogs) is the Budgerigar (genus: Melopsittacus).

Everyone loves the budgerigar!
(genus: Melopsittacus undulates), but few people know it has an unusually large/long lacrimal (tan) that curls under the orbit to contact the postfrontal (Fig. 2), as in it’s larger relative, Ara, the macaw. It looks like a typically jugal on other reptiles. The actual very birdy jugal appears beneath it (cyan).

Figure 2. The skull of Melopsittacus in three views. Note the tan lacrimal creating a false-jugal on top of the real jugal (in cyan).

Figure 2. The skull of Melopsittacus in three views. Note the tan lacrimal creating a false-jugal on top of the real jugal (in cyan). There’s a hinge between the nasal and frontal that lifts the premaxilla.

And where is the maxilla?
Hidden inside the premaxilla and overlapping nasal. The last of it is contacting the anterior jugal.

Figure 3. Melopsittacus skeleton. This is the budgie cut to the bone.

Figure 3. Melopsittacus skeleton. This is the budgie cut to the bone.

Melopsittacus undulatus (Linneaus 1758; extant ) is the extant budgerigar, a tiny parrot. Here the nasal wraps around the ventral naris. The lacrimal forms a send jugal below the orbit and contacts the postorbital and squamosal.

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.

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The Zygodactylidae revisited: Smith, DeBee and Clarke 2018

According to Smith, DeBee and Clarke 2018
“Zygodactylidae are an extinct lineage of perching birds characterized by distinct morphologies of the foot and wing elements.”

According to the LRT
(large reptile tree, 1137 taxa) zygodactyly (digits 1 and 4 retroverted) appeared several times by convergence in four unrelated bird clades, including toucansparrots, roadrunners and woodpeckers.

“Although the clade has a complex taxonomic history, current hypotheses place Zygodactylidae as the sister taxon to Passeriformes (i.e., songbirds).”

Earlier we learned that Eozygodactylus (Fig.1) nests with Geococcyx, the roadrunner. Among living zygodactylus birds, only parrots, like Ara, are close to the sparrow, Passer.

“Given the rather sparse fossil record of early passeriforms, the description of zygodactylid taxa is important for inferring potentially ancestral states in the largest radiation of living birds (i.e., the ~6,000 species of extant passeriforms).”

Actually
taxa related to Passer include only Passer at this point in the LRT. Other traditional passeriformes nest elsewhere.

“Despite the exceptional preservation of many specimens and considerable species diversity in Zygodactylidae, the relationships among species have not been previously evaluated in a phylogenetic context.”

Even so, 
the LRT has exposed a problem of taxon exclusion here.

“Herein, we …provide the first hypothesis of the species-level relationships among zygodactylids. The monophyly of Zygodactylidae is supported in these new analyses.”

Figure 2. Eozygodactylus reconstructed from figure 1.

Figure 2. Eozygodactylus reconstructed from figure 1. This represents  only one of four clades with a retroverted digit 4.

As defined by the authors,
“Zygodactylidae Brodkorb, 1971 is an extinct, comparatively species-rich clade of enigmatic birds that possess derived morphological features associated with a perching habitus (Mayr, 2008, 2009, 2015). Zygodactylidae is primarily characterized by a zygodactyl conformation of the pedal phalanges—possessing a retroverted fourth toe and associated accessory trochlea on the distal end of the tarsometatarsus (Olson & Feduccia, 1979).”

The authors chose woodpeckers (Piciformes) as the outgroup.
The unrelated basal barbet/toucan, Cyrilavis, nests at the first dichotomy along with the unrelated Nestor, the parrot. If you are starting to sense yet another case of taxon exclusion, then we are thinking along the same lines.

On the plus side, Botelho et al. 2014 reported
the zygodactyl foot evolved independently in different extant bird taxa.

References
Botelho JF, Smith-Paredes D, Nuñez-Leon D, Soto-Acuña and Vargas AO 2014. The developmental origin of zygodactyl feet and its possible loss in the evolution of Passeriformes.  Proceedings Biological Sciences 281(1788):20140765. doi: 10.1098/rspb.2014.0765.
Smith NA, DeBee AM and Clarke JA 2018.  Systematics and phylogeny of the Zygodactylidae (Aves, Neognathae) with description of a new species from the early Eocene of Wyoming, USA. PeerJ 6:e4950 doi: https://doi.org/10.7717/peerj.4950

The sand grouse (genus: Pterocles) revisited

The spark for this blogpost:
A PH reader considered the nesting of the sandgrouse Pterocles with the horned screamer, Anhima, a mismatch. And it is a mismatch in terms of size, color, feet, legs, etc. The thing is… in the LRT, where only skeletal traits are tested, no other tested taxon nested closer to Anhima than Pterocles.

Figure 1. Anhima adult and chick compared to Pterocles adults

Figure 1. Anhima adult and chick compared to Pterocles adults

Earlier I only had skull data (Fig. 4) for the genus Pterocles (Figs. 1–3) and with that heretically nested Pteroclesthe sand grouse, with Anhima, the screamer (Fig. 2). Sand grouse have traditionally been nested with pigeons and chickens, or between pigeons and chickens (Shufeldt 1901), which are not related to one another in the large reptile tree (LRT, 1236 taxa).

Figure 1. Skeleton of Pterocles, the extant sand grouse. Note the 'calcaneal' tubers and manual digit zero, along with the very tiny clavicle/furcula (green).

Figure 2. Skeleton of Pterocles orientalis arenarius, the extant black-bellied sand grouse. Note the ‘calcaneal’ tubers and manual digit zero, along with the very tiny clavicle/furcula (green). This is a different species than the skull shown in figure 3, hence the different mandible ventral margin shape and other differences.

Pterocles is phylogenetically miniaturized
compared to its larger sister, Anhima, the horned screamer (Fig. 2). Even so, and despite the much larger sternum and much smaller feet, Pterocles retains a digit zero process that also includes a spike in Anhima. Both taxa have a large ‘calcaneal heel’ behind the distal tibia, rare to absent in other birds. In Pterocles pedal digit 1 does not reach the substrate and the furcula is much smaller. Both share more traits with each other than with any other taxa among the 1236 taxa in the LRT.

In this case, at least,
the addition of the post-cranial data changed nothing in the LRT tree topology. It would have been less ‘trouble’ to have Pterocles nest with pigeons, or chickens, but a good scientist reports results, no matter how they differ from tradition.

FIgure 2. The larger Anhima compared to its smaller sister, Pterocles.

FIgure 3. The larger Anhima compared to its smaller sister, Pterocles. Note the digit zero spur on the manus along with the ‘calcaneal tuber’ behind the distal tibia.

Back in 1901
Shufeldt reported, “the sand grouse constitute a small assemblage of forms, related on one hand to the gallinaceous (chicken-like) birds, and on the other to the pigeons.” The two clades are not related to one another in the LRT. And that statement was made before the invention of the airplane, computer and PAUP.

Figure 1. Pterocles, the chestnut-bellied sandgrouse is not related to pigeons, despite convergent appearances, but more closely related to the screamer, Anhima.

Figure 4. Pterocles, the chestnut-bellied sandgrouse is not related to pigeons, despite convergent appearances, but more closely related to the screamer, Anhima.

The Fulica, Anhima, Petrolcles clade
is a basal one, probably extending back to the Early Cretaceous. It is a sister clade to the chicken/sparrow/parrot clade, far from the New World vulture/pigeon clade.

References
Shufeldt RW 1901. On the systematic position of the sand grouse (Pterocles: Syrrhaptes). The American Naturalist 35 (409):11–16.

 

Is a sandgrouse almost a pigeon? Is a sandgrouse almost a grouse?

No. And No.
No matter what you may read, a sandgrouse (genus: Pterocles) does not nest with pigeons in the large reptile tree (LRT, 1235 taxa), but with the screamer, Anhima. And those two do not nest with Tetrao tretix, the black grouse, which nests between chickens and sparrows in the LRT.

Figure 1. Pterocles, the chestnut-bellied sandgrouse is not related to pigeons, despite convergent appearances, but more closely related to the screamer, Anhima.

Figure 1. Pterocles, the chestnut-bellied sandgrouse is not related to pigeons, despite convergent appearances, but more closely related to the screamer, Anhima.

Pterocles exustus (Temminck 1815) is the extant chestnut-bellied sandgrouse. This vegetarian prefers bushy, arid lands.

References
Timminck CJ 1825. Atlas des oiseaux d’Europe, pour servir de complément au Manuel d’ornithologie de M. Temminck. Belin, Paris 1826–42.

wiki/Chauna
wiki/Fulica
wiki/Pterocles

Hello, Robin! Where do you nest?

Short answer:
Turdus migratorius (Linneaus 1758) nests between the crow (Corvus) and the jay (Cyanocritta) in the large reptile tree (LRT, 1232 taxa) based on skeletal traits. 

Figure 1. Turdus migratorius, the American robin, nests between the crow (Corvus) and the blue jay (Cyanocritta).

Figure 1. Turdus migratorius, the American robin, nests between the crow (Corvus) and the blue jay (Cyanocritta).

According to Prum et al. 2015
which tests DNA sequences, Turdus nests with 13 taxa not tested in the LRT along with Corvus, the crow. So there is some agreement here. However, the basal taxon in this subclade within a larger clade, Passeriformes, is Menura, the lyrebird.

By contrast,
in the LRT, Menura nests with cuckoos, apart from crows and jays.

Ironically,
the genus Passer (the sparrow) was not included in the Prum et al. study. In the LRT, Passer nests between chickens and parrots, apart from lyrebirds, robins, crows, and jays. So the Prum et al. study does not tell us if Passer is a passeriform or not. In the LRT, the lyrebird, crow and robin are not related to Passer.

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.

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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

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