Megachirella: Not at the origin of squamates. Lacertulus is older.

We looked at Lacertulus and the origin of the Squamata in the Late Permian
here in October 2011.

We looked at the splitting of the Tritosauria from the Protosquamata
here in December 2014.

Siimòes et al. 2018
proposed to nest Megachirella watchtleri (Fig. 1) at the origin of squamates in the Middle Triassic, 75 million years earlier than the previously known oldest squamate fossils. They reported, “For the first time, to our knowledge, morphological and molecular data are in agreement regarding early squamate evolution, with geckoes—and not iguanians—as the earliest crown clade squamates. Divergence time estimates using relaxed combined morphological and molecular clocks show that lepidosaurs and most other diapsids originated before the Permian/Triassic extinction event, indicating that the Triassic was a period of radiation, not origin, for several diapsid lineages.”

Figure 1. New µCT scans of Megachirella from Simoes et al. 2018.

Figure 1. New µCT scans of Megachirella from Simoes et al. 2018.

Unfortunately
|they did not include relevant taxa. According to the large reptile tree (LRT, 1224 taxa, www.reptileevolution.com/reptile-tree.htm) Megachirella nests at the base of the Rhynchocephalia (= Sphenodontia) along with Pleurosaurus (excluded from the Simoes team study) when many more relevant taxa are included.

Figure 2. Megachirella nests in the middle of this cladogram, that also nests turtles between rib gliders and choristoderes.

Figure 2. Megachirella nests in the middle of this cladogram, that also nests turtles between rib gliders and choristoderes.

 

Lacertulus is older (Late Permian) and more directly related to squamates.

FIgure 2. Megachirella (Renesto and Posenato 2003) is a sister to the BSRUG diapsid.

FIgure 3. Megachirella (Renesto and Posenato 2003) is a sister to the BSRUG diapsid and reconstructed here.

Nesting turtles with rib gliders
(Coelurosauravus) only hints at major flaws in the Simoes et al. cladogram topology. Nesting Sophineta and Palaegama close to and basal to Megachirella confirms findings made years earlier by the LRT. Marmoretta is also close, but nests within the Rhynchocephalia in the LRT.

Figure 2. Pleurosaurus and Palaeopleurosaurus skulls compared to those of sister taxa.

Figure 2. Pleurosaurus and Palaeopleurosaurus skulls compared to those of sister taxa.

Tijubina (which Simoes redescribed in 2012) is also missing from the Simoes et al. 2018 study.

Figure 1. Palaegama is basal to Coelurosauravus ('rib' gliders), Megachirella (rhynchocephalians), Lacertulus (protosquamates) and Tijubina (tritosaurs)

Figure 5. Palaegama is basal to Coelurosauravus (‘rib’ gliders), Megachirella (rhynchocephalians), Lacertulus (protosquamates) and Tijubina (tritosaurs)

 

 

References
Simòes T, and 8 co-authors 2018. The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Nature 557: 706â709 (2018)

Publicity
https://www.livescience.com/62693-mother-of-lizards-fossil.html

Advertisements

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

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.

Owlets: aptly named!

Owlets, like Aegotheles,
are like little owls, like Tyto, but they are not carnivores. Owlets are large-eyed nocturnal insectivores that feed on the wing. They are also transitional to swifts, like Apus, large-eyed diurnal insectivores that feed on the wing.

Figure 1. Aegotheles skull and in vivo. This clade is transitional from owls to swifts.

Figure 1. Aegotheles skull and in vivo. This clade is transitional from owls to swifts.

Traditionally
owlets are considered Caprimulgiformes. According to Wikipedia, “Traditionally, they were regarded, on morphological grounds, as being midway between the owls (Strigiformes) and the swifts. Like the owls, they are nocturnal hunters with a highly developed sense of sight, and like the swifts they are excellent flyers with small, weak legs.”

Figure 3. Tyto, the barn owl, nests very close to Apus, the swift.

Figure 2. Tyto, the barn owl, nests very close to Apus, the swift.

However… and I hate to tell you this,
Wikipedia reports, “Based on analysis of DNA sequence data – the families of the Caprimulgiformes to be members of the proposed clade Metaves, which also includes the hoatzin, tropicbirds, sandgrouse, pigeons, kagu, sunbittern, mesites, flamingos, grebes and swifts and hummingbirds (Fain and Houde 2004).

Figure 3. Skull of Apus, the common swift, closer to hawks and owls.

Figure 3. Skull of Apus, the common swift, closer to owlets and owls.

Prum et al. 2015, also using molecules,
nested Aegotheles basal to swifts and hummingbirds within a basal clade of owlet-nightjars derived from screamers (genus: Chauna) and currosaws (genus: Crax), both heavy-bodied ground birds.

The results of these and other bird DNA studies
should have reported that DNA analyses do not produce a tree topology that produces a gradual accumulation of traits, and so fail to echo trait studies. Instead, bird workers put their faith in what they could not see directly. Worse yet, they no longer believed the hard evidence that traits display. What happens to science when we no longer believe hard evidence? You get Fain and Houde 2004 and Prum et al. 2015.

References
Fain, MG and Houde P 2004. Parallel radiations in the primary clades of birds. Evolution. 58 (11): 2558–2573. doi:10.1554/04-235
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/Caprimulgiformes

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

Ashland, Oregon, pterosaur exhibit

I recognized some of the models
in this traveling pterosaur exhibit (Fig. 1). They came from Triebold Paleontology, but originated at David Peters Studio. Unfortunately, I’m not keen on the poses the exhibitors gave these pterosaurs. Ironically they are sprawling, like lizards, but no one, but yours truly has adopted the lepidosaur origin of pterosaurs hypothesis.

FIgure 1. Pterosaur exhibit

Here’s the way
Pterodaustro should be posed (Fig. 2). It’s a wader, built for walking knee deep into still shallow waters to dip that long filter-toothed mandible — yet able, in a moment to leap into the air and take flight. Still the hind limbs are sprawling.

Figure 2. Pterodaustro sculpture

Here’s the way
Jeholopterus should be posed (Fig. 3), digitigrade with the shoulders directly over the toes.  The long finger claws of this vampire pterosaur were ideal for latching onto and in to, dinosaur skin. And this is the correct skull. Triebold, tossed out the correct skull and placed the more popular, but invalid, Bennett anurognathid skull (the one that mistook the mandibles for sclerotic (eyeball) rings.

Model of Jeholopterus, the famous vampire pterosaur.

Figure 2. Model of Jeholopterus, the famous vampire pterosaur.

Here’s the way
Dimorphodon would run around on the ground – digitigrade (proximal phalanges elevated, too), shoulders over the toes, pedal digit 5 retroverted. Nothing clumsy or awkward about this basal pterosaur! It was fast, agile and keeping those large finger claws sharp for clinging to tree trunks.

 

Figure x. Dimorphodon skeleton.

Figure x. Dimorphodon skeleton. The tail, not found with the rest of the skeleton, making this a chimaera, is too long.

Here’s the text of the online article:
“Long before Tyrannosaurus rex, the world was filled with pterosaurs — bizarre-looking flying reptiles, some as huge as a fighter jet, who ate everything, terrorizing the Mesozoic Age for 160 million years until they, like the dinosaurs, were killed off by a big asteroid.

“That little-known world, our window into which has been vastly expanded by science in the last few decades, has been recreated in a stunning new ScienceWorks Hands-On Museum exhibit that invites you, at one point, to virtually think, feel and fly like a pterosaur by flexing your arms and body.

“Entirely created by the Ashland’s museum staff and volunteers, it was built for under $250,000, a modest amount among museums these days, especially when they saw a San Francisco museum did their pterosaur exhibit for 30 times that, says Steve Utt, co-creator and president of ScienceWorks board of directors.

“Costs for ScienceWorks can be recouped by leasing it out, he says.

“A self-described “Silicon Valley escapee” eight years ago, Utt did all the seemingly magical if not miraculous software and video that plops you right in the middle of the pterosaur’s world, which started 228 million years ago and seems a lot stranger than any science fiction movie.

“Pterosaurs (pronounced “terra-soars”) have replaced the once terrible tyrannosaurus rex, hero of Jurassic Park, as an object of fascination because, says ScienceWorks exhibit director Leo Palombo, “there have been so many discoveries, so much we didn’t know about 10 or 15 years ago, and that’s what you see here — flying reptiles. They are not dinosaurs, not birds. Some had hair, not feathers — so many amazing sizes and shapes.”

“They all used to be called pterodactyls, but that word is outmoded now and applies only to a small subcategory. Displays at ScienceWorks seek to show the immense, newly-discovered range of body types, sizes, combs (those wild shapes on top of their heads), as well as their body architecture, which can only be described as an extremely inventive chapter of evolution.

“Displays explain that pterosaurs in general had long, pointy heads, usually with teeth, could fly up to 70 mph and would gather food by scooping it from water, land or air. They are not like bats, though they have skin-like wings, and these were made possible by the evolution of the fourth finger to hold a wing.

“Many of the exhibits teach you what various species did, how and where they did it — and then you turn around and there’s a video of a familiar beach on the Oregon coast with a couple of pterosaurs soaring in among the breakers, then alighting on our big beach rocks, where they sit and peck and preen. It’s just, simply, hard to believe this ever happened in what’s now Oregon, let alone that we have an accurate, scientific depiction of it.

“Len Eisenberg of ScienceWorks’ science advisory board stands at the most popular interactive pterosaur “ride,” urging participants to arch their heads back and wave their arms, as sensors pick up all these cues. There’s a learning curve and most who try it get chomped by a giant-jawed mososaur (sic) when they crash in the water. You get points for various foods you kill — squid, fish or ammonite. A sign shows the best score of the day, a 20, and you, usually have zero. It takes several times in a long line to get up to the skill of the pterosaur.

“This display and the science around pterosaurs is interesting because we’ve found lots more fossils and footprints in the last decade,” says Eisenberg, “all of which explain how they lived and got food.”

“Another interactive ride shows a seeming x-ray of your flapping human thorax, set beside the ancient creature and giving us a window on how much muscle and thin, fragile, lightweight bone had to be brought into play for it to fly.

“The stunning centerpiece of the new exhibit is the lifesize, 16-foot tall wood model of Quetzalcoatlus, the largest known flying creature of all time, which exhibit technician Rachel Benbrook and others fashioned using Turbo CAD and Adobe Illustrator.

“The public reception to this exhibit has been overwhelmingly positive and,” she says, “many people, seriously, have been blown away. That’s what we want — to inspire and encourage science education to the next level.”
— John Darling is an Ashland freelance writer. Reach him at jdarling@jeffnet.org.”

References

http://www.dailytidings.com/news/20180430/imagination-soars-at-pterosaur-exhibit