New insights into the skull of the extant flying gurnard, Dactylopterus, bring it closer to the catfish, Clarias and the Late Silurian placoderm, Entelognathus (Fig 1), in the the large reptile tree (LRT, 2299 taxa, currently out of date during this revision) in this latest round of new insights. They keep coming.
Figure 1. The flying gurnard, Dactylopterus, compared to basal catfish and Late Silurian Entelognathus and Loganellia. New labels are here applied to Dactylopterus based on the catfish and placoderm Bauplan.
Catfish are freshwater taxa. Flying gurnards are marine. Both developed pre-pectoral ‘feelers, facial barbels in catfish, and specialized pectoral rays in gurnards, like those of sea robins. The flat, box-like skulls with similar bones in similar locations is a clue to their interrelationship.
Figure 2. The extant flying gurnard, Dactylopterus, is a close relative of basal catfish and the placoderm, Entelognathus based on new skull bone identities.
Dactylopterus volitans (Linneaus 1758; 50 cm) is the extant flying gurnard, a bottom-feeder living in warm shallow seas. Typically Dactylopterus is allied with long-snouted pipefish and seahorses. Here it nests with Clarias, the walking catfish. Dactylopterus has the skeletal remnant of a heterocercal tail, a primitive trait, hidden inside its forked diphycercal tail.
When startled the butterfly-like pectoral fins spread wide as the undulating tail pushes the fish away from danger. The tabulars are quite large and extend like a dorsal shield (Fig 1), but the medial dorsal shield/spine seen in basal catfish and placoderms is lost. The pelvic fins are below the giant pectoral fins, convergent with more derived fish. The anterior pectoral fin spines are separate from the large fan and are more mobile, like sea robin (Prionotus) ‘fingers’, but webbed.
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) .
The ocean sunfish (Mola mola) (Figs 1, 2) is one of the oddest vertebrates in the sea. They say it has a lumpy pseudotail (the clavus), replacing the common caudal fin. This marine giant swims by wagging its dorsal and anal fins. Females produce 300,000 planktonic eggs at a time.
Figure 1. Origin of the ocean sunfish (Mola) involves taxa close to Lagocephalus and Galaxias.
Hare (Figs 1, 2) are two much smaller ocean sunfish ancestors, according to the large reptile tree (LRT, 2299 taxa). They include tiny Galaxias and midsized Lagocephalus, the ocean puffer. The skulls show the loss or fusion of teeth, the reduction of the operculum and the shift in skull bone proportions.
Galaxias attenuatus (= Galaxias maculatus Cuvier 1816, 4–58cm depending on species, typically 10cm) is the Inanga, or common galaxias, an extant freshwater fish. It spends the first six months at sea. Galaxias is basal to several odd small fish and several much larger descendants (Figs 1, 2).
Lagocephalus lagocephalus (Linneaus 1758, 60cm) is the extant pufferfish, capable of swallowing so much water into its stomach that it turns into a sphere. Here it nests with the equally talented, but spinier porcupine fish. Ribs and pelvic fins are absent. The postfrontal extends behind the eyeball here.
Mola mola (Linneaus 1758) is the extant ocean sunfish. As a hatchling it is similar to a porcuipinefish (Diodon) in shape, then undergoes metamorphosis to adulthood. It is the largest extant bony fish and the only one taller than long. It is derived from the puffer fish in the LRT.
References Cuvier G 1816. Le règne animal distribué d’après son organisation, pour servir de base à l’histoire naturelle des animaux et d’introduction à l’anatomie comparée. Les reptiles, les poissons, les mollusques et les annélides. Déterville, Paris. Vol. 2, Edition 1: i-xviii, 1-532, (pls. 9-10, in v. 4). Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Basal members of the clade of bony ray-fin fish that arose from the placoderm, Entelognathus (Fig 1), did not stray too far from that Late Silurian Bauplan. They are the catfish, like extant Clarias and Eocene Hypsidoris(Fig 1), slow-moving bottom predators that inhabit fresh waters today.
Figure 1. Eocene catfish, Hypsidoris, retains skull patterns seen in Late Silurian Entelognathus. Some are fused. Others are split. The dorsal spine is a remnant of the placoderm carapace.
Synodontis, extant angel catfish (Fig 2), retains a bit more armor from the thorax, color-coded here to aid comparison.
Figure 2. Synodontis, the angel catfish, retains several placoderm traits lost in more derived taxa. The dorsal spine and lateral armor are retained from Entelognathus in figure 1.
Short one today. Let the graphics (Fig 1) tell the tale of re-identifying skull bones in these bony fish.
Figure 1. Fundulus, Xiphias and relatives, not to scale. Tetrapod homology colors added here. All former maxillae are here identified as overlapping lateral portions of the premaxilla seen in basalmost taxa in this clade, like Clarias, the catfish. The gray bone is derived from the dorsal armor of placoderms like Entelognathus. The swordfish (Xiphias) sword started off going the other way, as an ascending process in the top minnow, (Fundulus).
Reexamination of these taxa is showing previously overlooked evolutionary pathways. The work continues and nothing is set in stone here.
BTW, note how you can apply DGS colors to drawings, for your own ease of identifying bones AND make it easier for readers to understand and criticize your interpretations.
Following on the heels of yesterday’s post linking catfish and Entelognathus, the small-eyed Late Silurian placoderm, the most recent run of PAUP just split the largest number of bony ray-fin fish apart. Now more than half link to catfish and Entelognathus. The remainder still arise near the acanthodian – palaeoniscid split (Fig 1, click to enlarge).
Years earlier several other tested extant traditional bony ray-fin fish (e.g. Osteglossum,Engraulis, Acipenser, Polyodon) did not nest with the majority, but converged with them with regard to their skeletons and fins in the large reptile tree (LRT, 2299 taxa, subset Fig 1).
Figure 1. Click to enlarge. Subset of the LRT focusing on fish. Light green areas are traditional bony fish. Now one clade arises from the placoderm Entelognathus. Most of the remainder still arise near the acanthodian – palaenisciform split.
More work is needed to settle several issues. Many taxa are undergoing a revision of their skull colors and scores. In doing so several problems have been resolved. For instance, the traditional overlapping toothless ‘maxilla’ of many fish in the new clade can be phylogenetically traced back to toothless lateral extensions of the premaxilla going back to Clarias, the walking catfish. The operculum evolved several times (e.g. ratfish, paddlefish, sturgeons), now once more. Detecting the convergence in these traits by observation alone is not possible. It takes software and a minimum of taxon exclusion in your data set.
In other words, don’t “Pull a Larry Martin” and use a few traits to nest and label taxa. Convergence is out there. Instead, always use the last common ancestor method following testing hundreds of traits and hundreds of taxa in your own LRT. As you can see by my example, you might not get there the first time, but keep studying and let your cladogram tell you when you’re making scoring errors.
These insights might be the key to resolving the origin(s) of the bony ray-fin fish, which has been a year-long headache. More corrections and details to follow.
The following two graphics (Figs 1, 2) indicate present thinking here on the homologies present between the tiny-eyed placoderm, Entelognathus (Late Silurian) and two extant catfish, Hoplosternum and Clarias (Figs 1–4). Perhaps coincidentally, both extant taxa happen to be ‘walking’ catfish.
Figure 1. The extant armored catfish, Hoplosternum, compared to the Late Silurian placoderm, Entelognathus. Tetrapod homology colors added here.
Several skull bones are re-identified here based on long hours of study and many prior errors. A good Bauplan, like Entelognathus (Figs 1, 2), is essential to see how evolution has reshaped each extant taxon shown here.
Figure 2.The extant walking catfish, Clarias, compared to the Late Silurian placoderm, Entelognathus. Tetrapod homology colors added here.
Key to understanding catfish this time around comes from the premaxilla, which has vetigial lateral toothless extensions traditionally identified as maxillae. Those extensions are not found in Entelognathus, but shared by all catfish. Earlier two-toothed palatines projecting to the jaw margin (e.g. Clarias, Fig 2) were mis-identified as maxillae. Preconceptions are eventually overcome by continued study of the evidence.
The origin of the preoperculum (light yellow) and operculum (cyan) are different and distinct from those that develop independently in the clade Osteichthyes (= traditional bony fish). Details and diagrams will follow as patterns continue to clarify.
Figure 13 Hoplosternum in vivo. You can see the armor/bone beneath its shiny skin.
You can call these three taxa placoderms, but all bony fish and tetrapods are also placoderms in the LRT, since they all have placoderm ancestors.
Figure 4. Clarias, the walking catfish, in vivo.
Progress like this continues in the large reptile tree (LRT, 2299 taxa) as all fish taxa are currently (= over the past year) under scrutiny. Understanding tetrapod homologies in fish required a large number of taxa (= 480 or so), many more than years ago when these three these taxa were first added to the LRT, coincidentally, together. I trashed that post after more taxa apparently separated placoderms from catfish. Now they’ve come back together.
That’s the nature of freshman naiveté. That happens in home schooling environs like this. This hypothesis of interrelationships is not yet found in university textbooks. If so, please provide a citation so I can promote it here. This hypothesis also requires testing for confirmation, refutation or modification.
References Hancock J 1828. Notes on some species of fishes and reptiles, from Demerara, presented to the Zoological Society by John Hancock, Esq., corr. memb. Zool. Soc. In a letter addressed to the secretary of the Society. Zoological Journal, London v. 4: 240-247. Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Figure 3. Feroxichthys and kin as a subset of the LRT.
Most spiny sharks have a shark-like heterocercal tail. Middle Silurian Nerepisacanthus has something resembling a forked tail, convergent with those found in extant tuna, perch, etc.
We looked at those poor attempts at creating lateral fins that look like old brooms here. That trait is hard to score. Are they ray fins? Not exactly. Are they spine fins? Not exactly. Are they gathered spines? Maybe.
Brachyacanthus (originally Climatius scutiger, Egerton 1860; Hunterian Museum and Art Gallery 298251; 3.5 cm in length; Early Devonian) is a tiny acanthodian or ‘spiny shark’. The skull bones are subdivided more than any othe rtested taxon in the LRT. Several thin and parallel fin spines coalesce to form sharp, thick combined spines. Contra Carroll 1988, the small scales/bones that cover the head CAN be directly compared with the dermal skull bones of other taxa, including its sister, Paratarrasius.
Feroxichthys yunnanensis (Xu 2020; Middle Triassic; 29cm length; IVPP V 25692) is a possible durophagus (eating hard-shelled prey or corals) fish with robust premaxillary teeth. Like other colobodontids this fish has small, blunt button-like crushing teeth on the posterior jaws. Colobodontidae does not traditionally extend to Middle Silurian spiny sharks.
Ctenognathichthys bellottii(De Allesandri 1910, Tintori 1998, Middle Triassic, 21cm) “comb jaw fish” is a small relative of Feroxicthys. The hatchlings of moray eels (Gymnothorax) also have similar teeth. Note the flat skull and curved preoperculum.
Ctenognathichthys revista has a smaller face and deeper body with tiny fins.
References Burrow C 2011. A partial articulated acanthodian from the Silurian of New Brunswick, Canada. Canadian Journal of Earth Sciences. 48 (9): 1329–1341. Burrow C, Blaauwen JD and Newman M 2020. A redescription of the three longest-known species of the acanthodian Cheiracanthus from the Middle Devonian of Scotland. Palaeontologia Electronica 23(1):a15. Davis SP, Finarelli JA and Coates MI 2012.Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes. Nature 486:247–250. De Alessandri G 1910. Studii sui pesci triassici della I-ombardia. Mem. S!oc. 1t Sc. Nat., 3(1): 1-145, Milano. Egerton P de MG 1861. British fossils, pp 51-75. In Huxley TH (ed) Preliminary Essay Upon the Systematic Arrangement of the Fishes of the Devonian Epoch, Figures and Descriptions Illustrative of British Organic Remains. Memoirs of the Geological Survey UK (Decade 10). Kner R 1866.Die Fische der bituminosen Schiefer von Raibl in Kärnthen. Sitz Akad Wiss Wien, 53: 152–197. Tintori A 1998. Ctenognathichthys bellottii (de Alessandri, 1910): Nomenclature problems and stratigraphical importance of this Middle Triassic actinoopterygian fish. Rivista Italiana di Paleontologia e Stratigrafia 104(3)417–422. Woodward AS. 1889. Acanthodian fishes from the Devonian of Canada. Ann Mag Nat Hist 4:183–184. Xu, Ma and Zhao 2018. A large peltopleurid fish (Actinopterygii: Peltopleuriformes) from the Middle Triassic of Yunnan and Guizhou, China. Vertebrata PalAsiatica 56:106. Xu G-H. 2020.Feroxichthys yunnanensis gen. et sp. nov. (Colobodontidae, Neopterygii), a large durophagous predator from the Middle Triassic (Anisian) Luoping Biota, eastern Yunnan, China. PeerJ 8:e10229 DOI 10.7717/peerj.10229
Today’s newest Late Jurassic bird is a welcome addition. Unfortunately, this plover analog has been hyperbolized in the press as something weird.
From the Xu et al 2023 abstract “Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and spatio-temporally restricted fossil record”.
This is false. The evolutionary process that evolved birds from theropods is extremely clear in the large reptile tree (LRT, 2298 taxa) and everywhere else. Sometimes paleontologists make problems more superlative to get published in prestigious journals.
Figure 1. Fujianvenator reconstructed using the DGS method, here compared to scale with Archaeopteryx bavarica, the Munich specimen.
From the Xu et al 2023 abstract “Here we describe one of the stratigraphically youngest and geographically southernmost Jurassic avialans, Fujianvenator prodigiosus gen. et sp. nov., from the Tithonian age of China”.
This is coeval with the Solnhofen Formation, from which so many birds and pterosaurs have been recovered.
“This specimen exhibits an unusual set of morphological features that are shared with other stem avialans, troodontids and dromaeosaurids, showing the effects of evolutionary mosaicism in deep avialan phylogeny.
This is false.Fujianvenator nests with the Munich specimen of Archaeopteryx bavarica (Fig 1). Very few differences separate the two. The tibia is longer and the femur is shorter in Fujianvenator. The sternum is larger, anchoring larger pectoral (flapping) muscles.
It’s a better bird.
“F. prodigiosus is distinct from all other Mesozoic avialan and non-avialan theropods in having a particularly elongated hindlimb, suggestive of a terrestrial or wading lifestyle—in contrast with other early avialans, which exhibit morphological adaptations to arboreal or aerial environments.
True, but not that different from the Munich specimen, both nesting at the base of the Jeholornis, Mei, Yi clade, several of which were clearly flightless.
Taxon exclusion is present in Xu et all 2023. The authors included only one (but which one?) Solnhofen bird, which they labeled ‘Archaeopteryx‘ in their online cladogram.
Publicity from Nature.com ‘Weird’ dinosaur prompts rethink of bird evolution “The fossil is as old as the ‘first bird’, Archaeopteryx, and might have specialized in running or wading instead of flying.”
No. The wings are big enough, the sternum is bigger, the coracoids are long and the large furcula is gracile.
“One hundred and fifty million years ago, a young, bantam-sized, bird-like dinosaur became mired in a swamp in what is now southeastern China, and succumbed. Its fossilized remains, unearthed in 2022 and named Fujianvenator prodigiosus, show it to be one of the earliest bird-like dinosaurs to date from the Jurassic period. The researchers describe their discovery in a paper published today in Nature.”
Don’t tell me we’re getting mired in the tired old ‘is it a bird or dinosaur?’ argument again.
“This is really a weird animal within the group of birds,” says Mark Loewen, a palaeontologist at the University of Utah in Salt Lake City, who was not involved in the discovery.
To my eyes (Fig 1) Fujianvenator looks like the standard Late Jurassic bird, an analog to the extant plover (Fig 2).
“The creature had oddly lanky legs and might have lacked the ability to fly. It also doesn’t seem to conform to the accepted bird-evolution story.”
What exactly is the ‘accepted bird-evolution story”? Fujianvenator is just a slight variation on a Late Jurassic bird Bauplan. Is this headline-grabbing? A plover-like morphology is basal to a wide range of birds in the LRT.
“This study adds to mounting evidence that by the time of Archaeopteryx, dinosaurs had already diversified into different kinds of birds, Loewen says.”
The LRT showed the diversity of Solnhofen birds years ago. Time for someone else to create the reconstructions that show this again.
“Hailu You, a palaeontologist at the Chinese Academy of Sciences in Beijing and one of the co-authors of the paper, says that in the Jurassic, bird-like dinosaurs might have been occupying different ecological niches. “Early bird evolution is complicated,” he says.”
The LRT uncomplicated early bird evolution.
“Fujianvenator’s fossil lacks a head or a complete tail, but its body and limbs show a medley of traits similar to those of other bird-like dinosaurs, such as the relative lengths of the fingers, and details of the pelvis and vertebrae.”
No. It’s a close match to well known early bird taxa (Fig 1).
“But it didn’t have many modifications that would contribute to flight. For example, it had a shortened shoulder blade and fingers more specialized for grabbing.”
This is false. See figure 1. The lack of continuous PILs (parallel interphalangeal lines) in the manus indicate it was stiff, like flipper or a wing, not capable of flexion.
“Strangest of all are the bird’s hyper-elongated hind legs, in which the lower leg bone — the tibia — is twice as long as the thigh bone. Such long legs indicate a highly skilled runner, perhaps similar to a roadrunner (Geococcyx spp.), says Bhart-Anjan Bhullar, a palaeontologist at Yale University in New Haven, Connecticut.”
The term‘hyper-elongated” is hyperbole in this case. Fujianvenator has plover–like proportions (Fig 2), perfect for beaches surrounding lagoons.
Figure 2. Balearica compared to its sister in the LRT, Charadrius, the plover/kildeer.
Publicity from Nature.com continued “Alternatively, those stilts could have been used for wading. In the area where Fujianvenator was found, the researchers also uncovered a variety of swamp creatures, which they call the Zhenghe fauna. These fossils included fish, turtles and other aquatic reptiles. Swamps were a previously unknown habitat for early birds. To know whether the bird’s legginess was an adaptation to swamp life or high-speed running, researchers would need to examine the ends of its toes for signs of webbing — but those digits are poorly preserved. Either scenario is equally possible, the authors write.”
Ahh…. sanity returns.
Figure 3. The manus of Archaeopteryx bavarica compared to the manus of Fujianvenator. Not much difference. Metacarpal 3 is slightly longer than mt2 in both.
“Because of that scarcity of fossils, Fujianvenator helps to fill in some gaps in early bird evolution, says Bhullar. “Even at their earliest stages, the closest fossil relatives of birds were diversifying in interesting ways.”
No gaps were filled in the LRT, but another connection was made between Solnhofen and East Asian localities.
All the parts are there… just in different proportions asBrindabellaspis (Fig 1) joins Qilinyu (Figs 1, 2) at the base of the Placodermi. Neither had jaws. The size of the rostrum and missing parts in Brindabellaspis kept these two apart in the large reptile tree (LRT, 2297 taxa) until today.
Figure 1. Early Devonian Brindabellaspis to scale with Late Silurian Qilinyu.
Qilinyu rostrata (Zhu et al. 2016; Late Silurian, 419mya) nested close to Arandaspis and Poraspis. This mid-sized bottom feeder has a pointed rostrum and a small face. The ventral nostrils could have exited into the weak ventral oral cavity. Or they could have been blind pockets. The torso armor extended to the tiny pelvic fins, the most primitive known in this branch of the LRT.
Brindabellaspis stensioi (Young 1980; King B, Young GC and Long JA 2018; Early Devonian) was originally considered a strange sort of long-rostrum placoderm. Here it nests with a very primitive, short-rostrum placoderm, Qilinyu. Skull proportions have changed and the thorax shield is reduced. Enlarged prefrontals separate the frontals from each other.
King, Young and Long 2018b reported,“The anterior orientation of the facial nerve and related hyoid arch structures in this taxon resemble fossil osteostracans (jawless vertebrates) rather than other early gnathostomes.”
The previously overlooked proximity of Brindabellaspis to jawless Qilinyu and Poraspsis (Fig 2) is the reason why.
King, Young and Long 2018b did not mentionQilinyu in their text. Instead, they reported, “the skull roof pattern of Brindabellaspis is unique.”
Figure 2. Jawless Poraspis to scale with the related basal placoderm, Qilinyu. New tetrapod homology colors are applied here.
Poraspis brevis (Kiaer 1930; Klaer and Heintz 1935; Late Silurian to Early Devonian, 410mya; 10.5cm) is traditionally considered a member of the Heterostraci. Here Poraspis nests with Qilinyu, a basal member of the Placodermi. Both share spike-like fins.
You might remember an earlier post about a year ago in which Early Devonian Qilinyu was matched to Late Silurian Poraspis (Fig 2).
References Klaer J 1930. Ctenaspis, a new Genus of Cyathaspidian Fishes. Skr. Svalb. og Ishavet 33: Kiaer J and Heintz A 1935. The Downtonian and Devonian vertebrates of Spitsbergen. V. Suborder Cyathaspida. Part I. Tribe Poraspidei, Family Poraspidae Kiaer. Skrifter om Svalbard og Ishavet 40:1-138. King B, Young GC and Long JA 2018a. Placoderm Morphology. In: Vonk J and Shacklefor T Eds. Encyclopedia of Animal Cognitionition and Behavior. https://doi.org/10.1007/978-3-319-47829-6_1212-1 King B, Young GC and Long JA 2018b. New information on Brindabellaspis stensioi Young, 1980, highlights morphological disparity in Early Devonian placoderms. Royal Society. open science 5: 180094.http://dx.doi.org/10.1098/rsos.180094 Young GC 1980. A new Early Devonian placoderm from New South Wales, Australia, with a discussion of placoderm phylogeny. Palaeontogr. Abt. A Palaeozool-Stratigr. 167, 10–76. Zhu et al 2016. A Silurian maxillate placoderm illuminates jaw evolution. Science 354.6310:334-336.
Updated September 10, 2023 with restoration updates.
Another short one today as interesting hypothetical interrelationships keep accumulating in the LRT. Two late survivors of an Early Silurian radiation, Ozarcus and Palaeobates (Fig 1), are both updated here as the learning process continues.
Note the retention of placoderm post-cranial traits in Palaeobates (Fig 1), which otherwise has an eel-like morphology (long body, reduced lateral fins). It provides the current best clue to the unpreserved post-cranial morphology of Ozarcus.
On Ozarcus(Fig 2) the broken palatoquadrate = lacrimal is finally restored, the supposed premaxilla is removed and the two-part, two-hinge mandible is finally restored correctly.
Figure 1. Palaeobates and what little is known of Ozarcus compared to scale.
The dorsal spines arising from the back of the skull in both taxa are retained from the placoderm thorax armor. In Ozarcus the spine is not preserved, only the ‘alveolus’ that anchored the spine.
Ozarcus mapesae (Pradel et al. 2019; Early Carboniferous, 325 mya; AMNH FF20544, Fig 1) nests with shark-like, eel-like Palaeobates (Fig 1_. In the LRT both are derived from the much smaller and much earlier (Early Silurian) basal osteichthyan and derived placoderm, Shenacanthus. The Ozarcus teeth are extremely tiny, much smaller than each tooth basin in the already ribbon-like maxilla. The premaxilla is a tiny toothless area below the ventral nares. The narrowness of the skull is odd, perhaps unique, or unique to this clade.
Figure 2. Ozarcus skull. If a preoperculum and operculum were present, they may have looked like the transparent overlays.
Palaeobates angustissimus (Meyer 1849; Early Triassic, NMC 9980, originally Strophodus angustissimus Agassiz 1834, size?) is an eel-like basal osteichthyan nesting with Ozarcus. The large anal fin and caudal fin mark this late survivor of an Early Silurian radiation as an able swimmer. Ancestors include tiny Shenacanthus. These taxa left on extant relatives.
References Agassiz L 1843. Recherches Sur Les Poissons Fossiles. Tome I (livr. 18). Imprimerie de Petitpierre, Neuchatel xxxii-188. Meyer H v 1849. Fische, Crustaceen, Echinodermen und andere Versteinerungen aus dem Muschelkalk Oberschlesiens. Palaeontographica, 1: 216-242. Pradel A, Maisey JG, Tafforeau P, Mapes RH and Mallant J 2014. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 13185. doi:10.1038/nature13195e Zhu Y-A et al (10 co-authors) 2022. The oldest complete jawed vertebrates from the early Silurian of China. Nature 609:954–958. online
The Pterosaur Heresies 