From a recent µCT study of the Carboniferous fish, Coccocephalus wildi, (Fig. 1) CNN.com reported, “This is such an exciting and unanticipated find,” study coauthor Sam Giles, a vertebrate paleontologist and senior research fellow at the University of Birmingham, told CNN Thursday, adding that they had “no idea” there was a brain insidewhen they decided to study the skull.”
Silliness aside… I’ve not seen any other data on this taxon other than the skull.
On a more serious note, CNN also reported: “C. wildi was an early ray-finned fish, according to the researchers. C. wildi lacks this hallmark feature of ray-finned fish, with the configuration of a part of its forebrain called the “telencephalon” more closely resembling that of other vertebrates, such as amphibians, birds, reptiles and mammals, according to the study authors.”
That may be because in the large reptile tree (LRT, 2213 taxa) Coccocephalus wildi nests within the lobefin half of the basal dichotomy of bony fish that produced ray-fins (in general) and lobe-fins (in general + tetrapods). As noted earlier, many taxa in the lobe-fin clade (e.g. catfish) don’t have lobe fins.
Picking on one trait, like a ray fin, is what delighted the late professor Larry Martin.
Don’t come up with another explanation until you get your cladogram in order. “This indicates that the telencephalon configuration seen in living ray-finned fishes must have emerged much later than previously thought,” lead study author Rodrigo Tinoco Figueroa, a doctoral student at the University of Michigan’s Museum of Paleontology, said.
Get your cladogram in order. “Must” is no more powerful than “perhaps”, or “I’m guessing.” This is one more excellent study undercut by taxon exclusion. Build your own LRT.
It looked like a cat, and it was the size of a cat, but in the large reptile tree (LRT, 2212 taxa) the purported Eocene-Miocene felid, Eofelis (Fig. 1), nested with a more basal extant taxon, Mustela, the mink (Fig 1), which has a longer cranium.
So this is another case of convergence teased apart by the LRT. The LRT nests Eofelis and Mustela basal to the sabertooth clade, which is basal to the canid clade and the felid clade.
Eofelis edwardsii (Kretzoi 1938, Peigné 2001, MA-PHQ 348, Fig 1) was considered an early member of the Nimravinae, a cat-like clade often associated with sabertooth ‘cats’. Here Eofeilis nests with the more primitive Mustela, a European mink and a member of the weasel family. Weasels are basal to along list of carnivores, including cats, dogs, seals, sea lions and all sabertooth taxa.
Which brings us to Nimravus, a taxon traditionally known for ‘what it is not’. Everywhere one seeks information on Nimravus, the author reminds the reader it is not closely related to Smilodon, the larger and more famous sabertooth.
That’s true. In the LRT recently added Nimravus nests with Osbornodon(Fig 2), forming a sister clade with cats, several nodes apart from the sabertooth clade, which arises from minks and Eofelis (Fig 1), preceding dogs, cats and hyenas.
References Kretzoi M 1938. Die Raubtiere von Gombaszög nebst einer Übersicht der Gesamtfauna. Annales Musei Nationalis Hungarici 31: 88–157. Peigné S 2001. A primitive nimravine skull from the Quercy fissures, France: implications for the origin and evolution of Nimravidae (Carnivora). Zoological Journal of the Linnean Society 132:401–410. Werdelin L et al (3 co-authors) 0000. Phylogeny and evolution of cats (Felidae). Chapter 2 in Biology and Conservation of Wild Felids.
Today another set of insights in a single graphic (Fig 1). According to the large reptile tree (LRT, 2209 taxa) these five basal placentals are the most basal taxa for each of their clades. Presently there is no single last common ancestor, basal-most placental that is a placental in the LRT (see below). If you think these five look alike, they do look alike – because they are related.
The only extant aquatic marsupial, Chironectes, is the proximal outgroup for these five basal placentals. That makes this extant water opossum a “by default” last common ancestor and by that dint, a placental itself, if we didn’t know better. In counterpoint, placentals had their origin prior to the Early Jurassic (Fig 1) and in extant Chironectes both males and females have a waterproof pouch. So let’s call it a “stand-in by default” until a better last common ancestor comes along.
The LRT has not tested a last common ancestor for all placentals yet.
Oodectes > Carnivora is widely recognized as a basal member of the Carnivora. Here in the LRT Palaeocene, Oodectes(Fig 1) is the basal-most member.
Miacis > Chiroptera + Primates is widely recognized as a basal member of the Carnivoramorpha (but see below). Here in the LRT Palaeocene Miacis (Fig 1) is the basal-most member of the bats + primates.
Eupleres> moles + elephant shrews + tenrecs + toothed whales is widely recognized as a basal member of the Carnivora. Here in the LRT extant Eupleres (Fig 1) is the basal-most member of the least noticed clade in the Placentalia, all stem odontocetes.
Ptilocercus > Glires is widely recognized as a basal member of the Scandentia (but see below). Here in the LRT extant, Ptilocercus(Fig 1) is the basal-most member of Glires, the gnawing clade, that includes shrews, rabbits, rodents, Plesiadapiformes and Multituberculata.
Vulpavus > Onychodectes and kin + Xenarthra + Condylarthra is widely recognized as a basal member of the Carnivoramorpha (but see below). Here in the LRT PalaeoceneVulpavus (Fig 1) is the basal-most member of the clad that includes Onychodectes and kin + Xenarthra (= edentates) + Condylarthra (= Phenacodus and kin + Ungulata = all the large herbivore placentals including mysticetes ariding from hippos and desmostylians).
Some of these taxa have been difficult to tease apart, (Fig. 1) both in the literature and the LRT, which is fully resolved. Still not perfiect, but getting there.
Invalld clades: Carnivoramorpha (Wyss & Flynn, 1993) = Carnivora + all basal clades to Carnivora, but without creodonts. In the LRT creodonts are al marsupials. Similariites are due to convergence.
Scandentia (Wagner 1855) = tree shrews. Linneaus 1758 named Glires earlier.
Adding taxa to the large reptile tree (LRT, 2208 taxa, subset Fig 3) helps clarify interrelationships and morphologies. Turns out, at least in the science of taxonomics, more taxa are indeed better.
Recently the extant fish, Galaxias (Fig 1), entered the LRT and helped clarify certain ray-fin fish interrelationships and morphologies. Fish skull bone identities frequently need a primer or two to help identify them. Especially when you’re comparing bones to diagrams. Galaxias became that primer, forcing changes on a few, then many other taxa.
It all worked out. Earlier weaknesses at certain nodes in the ray-fin fish subset of the LRT were modified, replaced and strengthened. Corrections are part of the process of building the LRT and that will extend into the future as more primers reveal any future modifications.
Galaxias attenuatus (= Galaxias maculatus Cuvier 1816, 4–58cm depending on species, typically 10cm) is the Inanga, or common galaxias, an extant freshwater fish. This carp (Cyprinus) relative nests with Monocentris and Massamorichthys. Galaxias spends the first six months at sea.
According to Wikipedia Galaxias is a member of the order Galaxiiformes. Presently no other traditional and extant galaxiiformes have been tested by the LRT. On the Galaxias page, the next highest classification is Actinopterygii. That includes all ray-fin fish, so it doesn’t help establish where within Actinopterygii Galaxias belongs.
According to Wikipedia On the Galaxiidae (= Galaxiiformes) page, the next highest classification is Osmeromorpha. Clicking on that link brings one to Euteleostei. On that webpage Galaxiiformes nest between marine smelts and pike + salmon. The LRT (subset Fig 3) does not support that hypothesis of interrelationships.
Palaeocene Massaamorichthys is traditionally considered a percopsid, or perch. Perca, the perch, nests elsewhere on the LRT (Fig 3).
Extant Monocentris(Fig 4) is the Japanese pineapplefish, a traditional member of the Trachichthyformes. A traditional sister to Monocentris is the lanternfish, Anomalops, which nests in the LRT (Fig 3) with Sargocentron and more distantly with Perca, the perch. Perch and carp (Perca and Cyprinus) are not closely related in the LRT.
Likewise, Galaxias is not closely related to Lepidogalaxias, despite superficial similarities (small round skull with large orbit, long torso + tail, pelvic fins at mid length.
The present hypothesis of interrelationships now needs confirmation, refutation or modification with a similar taxon list and your own set of characters.
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).
Wilson et al. 2022 reported, “The relative scarcity of well-preserved fossils from the earliest history of stem lineages often limits our ability to establish robust, broad-based evolutionary patterns. This is certainly the case for the pan-radiation of archosaurs whose earliest stem taxa remain poorly understood relative to the crownward archosauriforms. Trilophosaurus buettneri is a North American Triassic stem archosaur that lies near the base of this expansive pan-radiation.”
Stop thinking Trilophosaurus is an archosauriform. It is a lepidosaur in the large reptile tree (LRT, 2207 taxa). It always has been. Adding taxa reveals this.
In addition, the earliest history of all stem lineages is well documented in the LRT, which documents ancestors back to the Cambrian. There’s no scarcity.
This trilophosaur = archosauriform myth is only the latest version of a myth first promoted by Benton 1985 (Fig 2). Yes, that’s the same vertebrate paleontology textbook author, Michael Benton, who holds huge sway in this field. He even convinced/cajoled his student, David Hone, to co-author two papers that undiscovered the ancestry of pterosaurs, which are also lepidosaurs.
Neither Benton 1985 nor other authors following him included enough taxa to recover the basal split following the last common ancestor of all reptiles in the LRT, Silvanerpeton. This embarrassing oversight due to taxon exclusion has clung to these authors and their followers like the myth of tail dragging in dinosaurs. Despite calls to fix this problem, there’s a curious lack of curiosity among paleoworkers. That lack should be a trait absent in a scientist, but in paleontology all evidence indicates it’s plesiomorphic.
Let’s add taxa to fix all decades-old problems, no matter what.
References Benton MJ 1985. Classification and phylogeny of the diapsid reptiles. Zoological Journal of the Linnean Society. 84 (2): 97–164. Wilson JD, Wisniewski A, Nesbitt S and Bever GS 2022. Comparative braincase morphology of Trilophosaurus buettneri and the early evolution of the pan-archosaurian neurocranium. Journal of Vertebrate Paleontology Article: e2123712
From the Beckett and Friedman 2015 abstract: “The monotypic scombrid fish Micrornatus is represented by a single skull from the early Eocene (Ypresian) London Clay Formation of southeastern England. Here we re-examine this specimen using computed microtomography. Scans reveal new details of the braincase, suspensorium and ventral hyoid arch. “
The huge (35cm) skull of Micrornatusis shown infigure 1.
It’s good to see workers coloring bones, but some standardization would be better. Here the authors’ colors are replaced with tetrapod homology colors used at ReptileEvolution.com (e.g. premaxilla = yellow, maxilla = green, etc). You might notice a few bones here (e.g. the nasals and frontals, the dentary and articular) are reidentified.
Micrornatus hopwoodi (Casier 1966, formerly Eocoelopoma hopwoodi, Beckett and Friedman 2015, early Eocene, BMNH 36136 = NHMUK PV OR 36136) was considered a mackerel close to Scomber, but in the large reptile tree (LRT, 2206 taxa) nests with Esox, the muskellunge (muskie, Fig 2) a type of pike. The premaxilla and its teeth on marine Micrornatus are much larger than on the freshwater pike, which has larger dentary teeth.
Micrornatus is more muskie (Esox) than mackerel (Scomber). This is what the LRT recovers (Fig 3). Micrornatus was likely a late survivor in the early Eocene.
TAt this point, eleven years into the project, the LRT (subset Fig 3) needs confirmation, refutation or modification by workers employing the same taxon list and a list of their own 200+ random characters.
References Beckett HT and Friedman M 2015. The one that got away from Smith Woodward: cranial anatomy of Micrornatus (Acanthomorpha: Scombridae) revealed using computed microtomography. In: Johanson Z Barrett PM, Richter M and Smith M (eds) Arthur Smith Woodward: His Life and Influence on Modern Vertebrate Palaeontology. Geological Society, London, Special Publications, 430, http://doi.org/10.1144/SP430.16 Pauca M 1929. Vorläufige Mitteilung über eine fossile Fischfauna aus den Oligozänschiefern von Suclânesti (Muscel). Acad. Roum. Sect. Sci. Bull. v. 12, p. 112-121.
Kligman et al 2023 announced the discovery of a tiny new stem caecilian, Funcusvermis gilmorei, known from a few broken and disarticulated parts (Fig 1). The new genus was found in the Late Triassic Chinle Formation of Petrified Forest National Park (PEFO), Arizona, USA.
Late Triassic Funcusvermis (Fig 1) is about the same size as the Early Jurassic crown caecilian, Eocaecilia(Fig 2), a derived member of the Microsauria in the large reptile tree (LRT, 2206 taxa, subset Fig 3).
Kligman et al considered Funcusvermis “the geologically oldest stem caecilian—a crown lissamphibian from the Late Triassic epoch of Arizona, USA—extending the caecilian record by around 35 million years.”
The LRT recovers a different tree topology (Fig 4) that separates caecilians from frogs + salamanders by simply adding taxa omitted by Kligman and his six co-authors.
Kligman et al followed a traditional myth still taught at the university level, that caecilians were closely related to frogs + salamanders. They did not test that old hypothesis by adding taxa. Kligman et al reported, “Living amphibians (Lissamphibia) include frogs and salamanders (Batrachia) and the limbless worm-like caecilians (Gymnophiona).”
Yes, there are only three living clades of ‘amphibians,’ but these three alone do not constitute a monophyletic group. Distinct from Kligman et al, the LRT (Fig 3) separates caecilians from frogs + salamanders with a long list of fossil taxa they and others traditionally omit. In the LRT caecilians are living microsaurs, apart from the clade Lissamphibia.
The stem caecilian question The Kligman et al hypothesis of interrelationships posited a rapid loss of large limbs from taxa like Celtedens (Fig 4) to Eocaecilia. Other caecilian-like taxa recovered by the LRT (Figs 2–5) were either omitted or recovered as convergent (some of these taxa are listed below).
I would be more interested in arguments for convergence if Kligman et al had included the microsaur taxa in the LRT (subset Fig 3) they omitted. With regard to time, the LRT recovers older stem caecilians than Late Triassic Funcusvermis (Fig 5).
Because Late Triassic Funcusvermis, is known from only a few mandibles (aka pseudodentaries) and a scattering of dissassociated other bones, the “funky worm,” Funcusvermis, will not be added to the LRT.
Kligman et al. wrote, “We tested the relationships of Funcusvermis gilmorei in a modified dataset of 63 terminal taxa including stem tetrapods, stem and crown amniotes, and temnospondyl amphibians including stereospondyls and lissamphibians.”
63 cherry-picked taxa is not enough, according to the LRT. Those 63 taxa gave the authors a distorted idea how tetrapods evolved from fish, which taxa were basal to reptiles, and which taxa were related to caecilians. Adding taxa resolves all issues. Omitting taxa does not.
In either hypothesis (Figs 2, 4) caecilians are the product of phylogenetic miniaturization and neotony. Perhaps those details are worth exploring sometime soon.
Publicity phys.org/news reported: “The smallest of newly found fossils can upend what paleontologists know about our history.”
Not true. Caecilians are not in the human lineage. Neither are frogs nor salamanders.
“A team of paleontologists from Virginia Tech and the U.S. Petrified Forest National Park, among others, have discovered the first “unmistakable” Triassic-era caecilian fossil—the oldest-known caecilian fossils—thus extending the record of this small, burrowing amphibian by roughly 35 million years. The find also fills a gap of at least 87 million years in the known historical fossil record of the amphibian-like creature.”
The time span between the Late Triassic of Funcusvermisand the Early Jurassic of Eocaecilia is actually somewhat less than 87 million years.
“The discovery of the oldest caecilian fossils highlights the crucial nature of new fossil evidence. Many of the biggest outstanding questions in paleontology and evolution cannot be resolved without fossils like this,’ said Kligman, ‘Seeing the first jaw under the microscope, with its distinctive double row of teeth, sent chills down my back,” Kligman said. “We immediately knew it was a caecilian, the oldest caecilian fossil ever found, and a once-in-a-lifetime discovery.”
That double row of teeth on such tiny jaws (Fig. 1) is a strong sign of caecilian affinity.
Crucial? Biggest? Outstanding? Chills down my back? Once-in-a-lifetime? I wonder if Romer, Colbert, Broom, Marsh and Cope ever got this excited about their discoveries? Or is this Kligman’s nature? Or just a sign of the modern age of Internet journalism?
Sounds like a Disney cartoon, but it’s the latest match made on the large reptile tree (LRT, 2206 taxa). Now Sphyraena, the barracuda, and Elops, the ladyfish (Figs 1 and 2) nest together between the cod (Gadus) and the cobia (Rachycentron). Let’s take a closer look.
Phylogenetic miniaturization and reversal evolved the ladyfish from the barracuda. In Elops, the ladyfish, the rostrum is shorter, the orbit is larger, the post-circumorbital bones are larger, the teeth are smaller (and so are its prey), the parietals contact each other medially, the pelvic fins are set further toward the tail, and the dorsal fin is above the pelvic fins, rather than above the anal fin (Figs 1, 2).
These newly evolved traits all make Elops look like a more primitive taxon. That’s what makes phylogenetic analysis a little tricky. That’s why it’s important to do a little ‘housekeeping‘ every so often. Take a look at a series of barracuda larvae shown below (Fig 4) for confirmation of this novel hypothesis on interrelationships.
These bauplan changes between Sphyraena and Elops are part of the reason why this interrelationship went unnoticed until now. Related taxa, like the cod and cobia, share more traits with the barracuda. Elops is the oddball, often, but not always, the morphological exception at its present nesting in the LRT. Even so, trust your software because it recovers a longer list of similar traits that nest Elops with Sphyraena rather than elsewhere. That’s called maximum parsimony, the guiding principle behind phylogenetic analysis. And that’s why “Pulling a Larry Martin” (relying on just one or only a few traits) should be avoided.
Matsuura and Suzuki 1997 provided a diagram of barracuda embryos and hatchlings (Fig 4) in which the rostrum is initially short and the orbit large relative to older barracuda. Note the dual dorsal fins at the last stage. Dual dorsal fins are found in related cod (Gadus). The anterior dorsal fin is retained by Elops, the ladyfish. The anterior dorsal fin is lost in adult Sphyraena, the barracuda. With these observations, larval development in Sphyraena, the barracuda, supports the recovery of Elops, the ladyfish as a close relative in the LRT largely due to phylogenetic miniaturization and reversal.
According to Wikipedia, Elops is a member of the Elopiformes, then the Actinopterygii. Traditional members of the elopiformes include the tarpon, Megalops. The LRT does not support that hypothesis of interrelationships. Wikipedia does not connect the barracuda and the ladyfish.
Rather than indicate broad, vague and nebulous interrelationships, like Wikipedia reports, the LRT documents the interrelationships and ancestries of every included taxon down to the level of genus back to the last common ancestor, a Cambrian or Ediacaran nematode worm close to Enoplus. As always, this novel hypothesis of interrelationships (Fig 3) now needs competing studies for confirmation, refutation or modification.
References Matsuura Y and Suzuki K 1997. Larval development of two species of barracuda, Sphyraena guachancho and S. tome (Teleostei: Sphyraenidae), from southeastern Brazil. Ichthyological Research 44:369–378.
By contrast in the large reptile tree (LRT, 2206 taxa, subset Fig 2) sailfish and swordfish are not in separate orders, but are only two nodes apart.
The sails (= tall dorsal fins) came first, before the swords. Swordless Late Cretaceous Pentanogmius(Fig 1) has a tall sail. So does swordless Alepissaurus (Figs 1, 2). According to these results (Fig 2) sailfish and swordfish diverged at 70mya, not 15mya and without a sword. So the sword is convergent.
If you’re wondering how Anguilla, the European eel, is related to Xiphias, the swordfish, we covered that earlier here. Baby swordfish look more like eels (Fig 3). Neotony gave us eels.
Pentanogmius evolutus (originally Anaogomius or Bananogmius evolutus Cope 1877; Taverne 2004; Late Cretaceous; 1.7m long) is traditionally considered a member of the Tselfatiiformes, thought to have gone extinct in the Late Cretaceous. Here it nests with Istiophorus, the extant sailfish.
Istiophorus platypterus (Shaw 1792 in Shaw and Nodder 1792; 3m) is the extant sailfish descending from Late Cretaceous Pentanogmius. The rostrum is extended, convergent with another fast, open ocean predator, the swordfish, Xiphias. The anterior dorsal fin is larger than the lateral area of the fish itself. Teeth are absent. The pectoral fins are long and slender. The anal fin is divided in two. The vertebral column is composed of relatively few, but large vertebrae.
Xiphias gladius (Linneaus 1758; Gregory and Conrad 1937; up to 4.5m in length) is the extant swordfish, nesting between Bavarichthys and Anguilla. 1cm long hatchlings more closely resembled little eels, then growing to little sailfish before reducing the long dorsal fin. The sword is not used to spear, but to slice and maim smaller fish traveling in schools. The pelvic fins and ribs are absent, as in eels. Larger females produce more eggs, up to 29 million.