Goodbye Batoidea, another traditional clade invalidated by the LRT

According to Wikipedia,
“Batoideais a superorder of cartilaginous fishes commonly known as rays. They and their close relatives, the sharks, comprise the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces.”

Figure 1. Spotted eagle ray skull shows the anterior portions of the pectoral fins jointed medially to create a digging snout.

Figure 1. Spotted eagle ray skull shows the anterior portions of the pectoral fins conjoined  medially to create a digging snout.

Aeobatus narinari (Figs. 1–3 originally Raja narinari Euphrasén 1790; 5m in length, 3m wingspan) is the extant spotted eagle ray and the subject of today’s post.

The distinctive flat muscular snout
is created by the anterior processes of the pectoral fins conjoining anteriorly, as in other stingrays that also have detachable venom spines at the base of their tail.

Figure 2. Subset of the LRT focusing on basal vertebrates. Purple taxa are traditional rays, here shown to be convergent in their morphology.

Figure 2. Subset of the LRT focusing on basal vertebrates. Purple taxa are traditional rays, here shown to be convergent in their morphology.

Traditionally
Aeobatus was considered a ray that should have nested with the guitarfish, Rhinobatos and even closer to Manta, the manta ray. Everyone considered that clade, Batoidea, monophyletic prior to today’s post.

When you expand your taxon list, as in the large reptile tree (LRT, 1586 taxa; Fig. 2), Aeobatus nests with Squatina, the angel shark, not with Manta or Rhinobatos. That means the three tested rays are convergent.

So say goodbye
to the Myliobatiformes. Say goodbye to the Rajiformes. And say goodbye to the Batoidea. These clades are not monophyletic in the LRT, but evolved a ray-like appearance by convergence. This hypothesis of interrelationships was apparently overlooked by prior workers. Please let me know if otherwise and I will promote that citation. Meanwhile, following the scientific method, independent testing using a similar taxon list should take place to confirm or refute this hypothesis.

While free swimming (rather than bottom dwelling)
and capable of leaping clear of the water, the spotted eagle ray feeds on shelled invertebrates hiding beneath sea sands. Distinct from Squatina, the marginal jaws of Aetobatus are nearly toothless. The vomer and a medial plate between the dentaries include a series of flat plates acting as crushing palatal teeth distinct from other tested rays.

Figure 2. The spotted eagle ray, Aetobatus in vivo.

Figure 3. The spotted eagle ray, Aetobatus in vivo.

Compare Aetobatus to its LRT sister,
Squatina oculata
 (Bonaparte 1840; Figs. 4, 5), the extant smooth back angelshark. In this  basal fish some of the gill bones are transformed to jaws with teeth, as in typical sharks. In general morphology Squatina is little changed from the Early Silurian jawless thelodonts that preceded it.

Figure 5. Squatina skull. Note the gill bars framing the mouth. These are modified in Aetobatus into a digging snout.

Figure 4. Squatina skull. Note the gill bars framing the mouth. These are modified in Aetobatus into a digging snout.

Distinct from rays,
the gill slits appear anterior to the expanded anterior processes of the pectoral fins in Squatina (Fig. 6), demonstrating how the gill slits shift ventrally in rays. These same anterior processes form the rostrum in Aetobatus (Fig. 1).

Figure 6. Squatina in vivo, lateral view. The large pectoral and pelvic fins give Squatina a broad, ray-like appearance in dorsal view.

Figure 5. Squatina in vivo, lateral view. The large pectoral and pelvic fins give Squatina a broad, ray-like appearance in dorsal view.

I’m only guessing,
but based on the present results, long-nosed stingless skates are going to nest with Rhinobatos, the guitarfish. Stingray, including cow nose rays, will nest with Aetobatus. And Manta will continue to nest alone among rays, as no other is a plankton feeder with an anterior gaping mouth without teeth. It’s closest relative is Rhincodon, the whale shark, the most primitive gnathostome (vertebrate with jaws) in the LRT.

FIgure 7. Squatina in ventral view showing the anterior processes of the pectoral fin that develop into a rostrum in Aetobatus and shift the gill slits ventrally.

Figure 6. Squatina in ventral view showing the anterior processes of the pectoral fin that develop into a rostrum in Aetobatus and shift the gill slits ventrally.

We’ve seen convergence before
in pterodactyloid-grade pterosaurs, turtles, whales, and dozens of other taxa. Convergence can produce false positive results if you omit key taxa. So far the LRT has been able to sort it all out by including overlooked taxa and avoiding genomic data.

When I started
ReptileEvolution.com eight years ago, I thought many of these issues were resolved long ago. While discoveries like this keep me digging for more, academic workers should have resolved these issues decades ago. Traditions persist for a reason.


References
Euphrasén BA 1790. Raja (Narinari). Kongl. Vetenskaps Academiens Nya Handlingar, 11:217-219.

wiki/Spotted_eagle_ray

Hongshanxi: just barely NOT a squamate

Dong, Wang, Mou, Zhang and Evans 2019 bring us
Hongshanxi xidi, a tiny, new and rare, complete, articulated and flattened Oxfordian (earliest late) Jurassic lepidosaur the authors had difficulty nesting with both traits and molecules.

In happy contrast,
the large reptile tree (LRT 1578 taxa) recovers Hongshanxi as the proximal outgroup to the clade Squamata, between Liushusaurus (Evans and Wang 2010) Early Cretaceous, ~10 cm) and IguanaEuposaurus cirinensis (Lortet 1892, MHNL 15681, Late Jurassic, Kimmeridgian, 155 mya, 3.5cm snout vent length) without firsthand observations.

Figure 1. Hongshanxi in situ with DGS colors added to pectoral region.

Figure 1. Hongshanxi in situ with DGS colors added to pectoral region.

From the abstract
It [Hongshanxi] is distinguished from other Jurassic-Cretaceous lizards by a unique combination of derived characters, notably a long frontal with posterior processes that clasp the short parietal; cranial osteoderms limited to the lower temporal and supraocular regions; and an elongated manus and pes. Phylogenetic analysis using morphological data alone places the new taxon on the stem of a traditional ‘Scleroglossa’, but when the same data is run with a backbone constraint tree based on molecular data, the new taxon is placed on the stem of Squamata as a whole. Thus its position, and that of other Jurassic and Early Cretaceous taxa, seem to be influenced primarily by the position of Gekkota.”

Figure 2. Hongshanxi skull with DGS colors added.

Figure 2. Hongshanxi skull with DGS colors added.

Unfortunately
Dong et al. were using an outdated and incomplete taxon list, that of Gauthier 2012 (610 characters, 192 taxa) with maybe a dozen additional Early Cretaceous taxa described since then. The authors report, “However, as with many other Jurassic and early Cretaceous taxa (e.g. Scandensia, Yabeinosaurus, Hoyalacerta, Liushusaurus), the phylogenetic position of Hongshanxi n. gen. cannot be clearly resolved.”

That may be because the authors do not understand that a series of lepidosaurs preceded the Squamata. These predecessors include the pterosaur clade, Tritosauria. In the LRT the Lepidosauria is completely resolved with high Bootstrap values at nearly all nodes with the addition of Hongshanxi, which looks quite a lot like its nearly coeval sister taxa and is similar in size and location.

Figure 3. Hongshanxi pelvic region in situ with DGS colors added

Figure 3. Hongshanxi pelvic region in situ with DGS colors added

The authors also do not realize
they cannot rely on molecular studies to clarify relationships in deep time. The solution to these problems is online, the LRT, ready for anyone to use. If workers want to continue ‘spinning their wheels’ recovering no clear solutions, that’s to the detriment of our science.

Oddly
the hands and feet of Hongshanxi are elongate, like their arboreal sisters, but the penultimate phalanges are shorter than the more proximal phalanges, distinct from their arboreal sisters. The torso is short relative to the femur length. The authors correctly note the very odd lack of a straight frontal-parietal suture. Also very odd is the open acetabulum (hip joint), which was overlooked by the authors.


References
Dong L, Wang Y, Mou L, Zhang G and Evans SW 2019. A new Jurassic lizard from China in Steyer J.-S., Augé M. L. & Métais G. (eds), Memorial Jean-Claude Rage: A life of paleo-herpetologist. Geodiversitas 41 (16): 623-641. https://doi.org/10.5252/geodiversitas2019v41a16.

http://geodiversitas.com/41/16

 

Dyoplax skull under DGS

Today,
the benefits of better data are presented.

Earlier
we nested the sole example of a traditional enigma croc, Dyoplax (Figs, 1, 2; Fraas 1867), in the large reptile tree (LRT 1559 taxa) based on a 19th century drawing (Fig. 1). With that sketchy data, Dyoplax nested basal to the clade(s) of marine crocodiles.

Figure 1. Dyoplax arenaceus Fraas 1867 is a mold fossil recently considered to be a sphenosuchian crocodylomorph. Here it nests as a basal metriorhynchid (sea crocodile) in the Late Triassic.

Figure 1. Dyoplax arenaceus Fraas 1867 is a mold fossil recently considered to be a sphenosuchian crocodylomorph. Here it nests as a basal metriorhynchid (sea crocodile) in the Late Triassic.

Maisch et al. 2013
provided a closeup photo and interpretive drawing of the skull (Fig. 2). Their interpretation and analysis tentatively put Dyoplax close to another traditional enigma, the croc with indented jaw margins, Erepetoscuchus. No cladogram was presented. Rather a list of shared traits was proposed by them and by prior authors. Yes, by listing traits, they were ‘Pulling a Larry Martin.’  The keywords ‘Dibothrosuchus‘, ‘Thalattosuchia’ and ‘marine’ were not found in the pdf text. So, yes, evidently they were excluding taxa.

By contrast,
using the new data from the skull published in Maisch et al., together with DGS and the LRT all work together to keep Dyoplax at the base of the marine crocodiles, far from Erpetosuchus. Dibothrosuchus remains the outgroup taxon for the sea crocs + river crocs.

Figure 3. Added 08/09/19 from Maisch et al. 2013. DGS sutures do not match sutures found by Maisch et al. (drawing) Hypothetical missing parts based on phylogenetic bracketing ghosted on in color

Figure 3. Added 08/09/19 from Maisch et al. 2013. DGS sutures do not match sutures found by Maisch et al. (drawing) Hypothetical missing parts based on phylogenetic bracketing ghosted on in color

Sea crocs have a longer rostrum
with maxillae that contact one another dorsally. The nares merge. 

Figure 7. Dibothrosuchus nests basal to all later quadrupedal crocs, including marine crocs, in the LRT.

Figure 4. Dibothrosuchus nests basal to all later quadrupedal crocs, including marine crocs, in the LRT. The hind limbs are unknown.

Subtext to this blogpost:
Several mistakes (using the old etching) need not misdirect the software as it employs hundreds of traits to nest hundreds of taxa. I have employed less than optimal data (Fig. 1) often enough. Taxon inclusion remains the key to understanding systematics. Without relevant taxa, enigmas and apparently unique taxa are more difficult to nest.


References
Fraas O 1867. Dyoplax arenaceus, ein neuer Stuttgarter Keuper-Saurier. Jh. Verein vaterländ. Naturk. Württemberg 23:108-112; Stuttgart.
Lucas SG, Wild R, Hunt AP 1998. Dyoplax O. Fraas, a Triassic sphenosuchian from Germany. Stuttgarter Beiträge zur Naturkunde, B. 263: 1–13.
Maisch MW, Matzke AT and Rathgeber T 2013. Re-evaluation of the enigmatic archosaur Dyoplax arenaceus O. Fraas, 1867 from the Schilfsandstein (Stuttgart Formation, lower Carnian, Upper Triassic) of Stuttgart, Germany. Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen. 267 (3): 353–362.

wiki/Dyoplax

 

Meet Seazzadactylus, the newest Late Triassic pterosaur

Dalla Vecchia 2019 introduces us to
Seazzadactylus venirei (Figs. 1–3; MFSN 21545), a small Late Triassic pterosaur known from a nearly complete, disarticulated skeleton (Fig. 2). The tail is supposed to be absent, but enough is there to show it was very gracile. The gracile feet are supposed to be absent, but they were overlooked. The rostrum was artificially elongated, but a new reconstruction (Fig. 3) takes care of that. A jumble of tiny bones in the throat (Fig. 4) were misidentified as a theropod-like curvy ectopterygoid, but the real ectopterygoid fused to the palatine as an L-shaped ectopalatine was identified (Figs. 3,4). 

Figure 1. Seazzadactylus nests between the two Austriadactylus specimens in the LPT.

Figure 1. Seazzadactylus nests between the two Austriadactylus specimens in the LPT.

Seazzadactylus is a wonderful find,
and DGS methodology (Fig. 1) pulled additional data out of it than firsthand observation, which was otherwise quite thorough (with certain exceptions).

Figure 2. Seazzadactylus in situ and tracing from Dalla Vecchia 2019. Colors added here.

Figure 2. Seazzadactylus in situ and tracing from Dalla Vecchia 2019. Colors added here.

Dalla Vecchia reports

  1. The premaxillary teeth are limited to the front half of the bone. Dalla Vecchia did not realize that is so because, like other Triassic pterosaurs, the premaxilla forms the ventral margin of the naris, dorsal to the maxilla (Fig. 3).
  2. A misidentified theropod-like ectopterygoid and pterygoid. Dalla Vecchia should have known no pterosaur has an ectopterygoid shaped like this. Rather the curvy shape represents a jumble of bones (Fig. 4). The real ectopalatine in Seazzadactylus has the typical L-shape (Figs. 3, 4) found in other pterosaurs.
  3. The scapula is indeed a distinctively wide fan-shape.
  4. The proximal caudal vertebrae are present, as are several more distal causals. All are tiny.
Figure 3. Seazzadactylus reconstructed using DGS methods.

Figure 3. Seazzadactylus reconstructed using DGS methods. No such reconstruction was produced by Dalla Vecchia. This is a primitive taxon precocially and by convergence displaying several traits found in more derived taxa.

Figure 4. Seazzadactylus bone jumble, including the L-shaped ectopalatine (orange + tan).

Figure 4. Seazzadactylus bone jumble, including the L-shaped ectopalatine (orange + tan). No pterosaur has a theropod-like ectopterygoid. That’s a loose jumble of bone spurs and shards.

It is easy to see how mistakes were made.
Colors, rather than lines tracing the bones, would have helped. Using a cladogram with validated outgroup taxa and more taxa otherwise were avoided by Dalla Vecchia for reason only he understands.

Figure 5. Seazzadactylus pectoral girdle.

Figure 5. Seazzadactylus pectoral girdle.

Phylogenetically Dalla Vecchia reports,
Macrocnemus bassaniiPostosuchus kirkpatricki and Herrerasaurus ischigualastensis were chosen as outgroup taxa.” (Fig. 6)

Funny thing…
none of these taxa are closely related to each other or to pterosaurs (Macrocnemus the possible distant exception) in the large reptile tree (LRT, 1549 taxa) where no one chooses outgroup taxa for pterosaurs. PAUP makes that choice from 1500+ candidates.

Figure 5. Cladogram by Dalla Vecchia 2019 showing where Seazzadactylus nests

Figure 6. Cladogram by Dalla Vecchia 2019 showing where Seazzadactylus nests. Their is little to no congruence between this cladogram and the LPT (subset Fig. 7), exception in the anurognathids. This cladogram needs about 200 more taxa to approach the number in the LPT.

Within the Pterosauria,
Dalla Vecchia nests his new Seazzadactylus between Austriadraco and Carniadactylus within a larger clade of Triassic pterosaurs that does not include Preondactylus, Austriadactylus or Peteinosaurus. Dalla Vecchia’s cladogram includes 27 taxa (not including the above mentioned outgroup taxa). In the large pterosaur tree (LPT, 239 taxa) Austriadraco (BSp 1994, Fig. 8) is a eudimorphodontid basal to all but two members of this clade. Carniadactylus (Fig. 8) is a dimorphodontid closer to Peteinosaurus. So there is little to no consensus between the two cladograms.

Figure 7. Subset of the LPT focusing on Triassic pterosaurs.

Figure 7. Subset of the LPT focusing on Triassic pterosaurs and their many LRT validated outgroups.

Publishing in PeerJ may cost authors $1400-$1700 (or so I understand).
Dalla Vecchia asked his Facebook friends for monetary help to get this paper published. I offered $900, but only on the proviso that the traditional outgroup taxa (listed above and unknown to me at the time) not be employed. You can understand why I cannot support those invalidated (Peters 2000) outgroups. Dr. Dalla Vecchia’s rejected my offer with a humorless invective of chastisement that likened my offer to one traditionally made by the Mafia. A more polite, ‘no thank-you,’ would have sufficed. Just today I learned of Dalla Vecchia’s ‘chosen’ outgroups. Kids, that’s not good science.

Figure 6. Seazzadactylus sister taxa in the Dalla Vechhia 2019 cladogram to scale.

Figure 8. Seazzadactylus sister taxa in the Dalla Vechhia 2019 cladogram to scale.

Bottom line:
A great new Triassic pterosaur! We’ll hash out the details as time goes by.


References
Dalla Vecchia FM 2019. Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the Upper Triassic (Norian) of northeastern Italy. PeerJ 7:e7363 DOI 10.7717/peerj.7363
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

The salamanderfish and the lizardfish enter the LRT together

Earlier we looked at a new extant deep sea sister for the Devonian basal ray fin fish, Cheirolepis (Fig. 1). Today, we add two more overlooked extant cousins (Figs. 2,3) to the Cheirolepis branch of the the LRT.

Figure 1a. Cheirolepis fossils.

Figure 1a. Cheirolepis fossils from Devonian strata. Note the upper one leans toward acanthodians (spiny sharks).

An overlooked extant saltwater shoreline taxon
Trachinocephalus myops (Fig. 2), the blunt-nosed lizardfish, nests with Cheirolepis in the large reptile tree (LRT, 1527 taxa). A variety of living lizardfish are known. Some are deep sea denizens.

Figure 1. The lizardfish, Trachinocephalus with colors added. Diagram from Gregory 1936. This taxon nests with Devonian Cheirolepis, a basal ray-fin fish.

Figure 2. The lizardfish, Trachinocephalus with colors added. Diagram from Gregory 1936. This taxon nests with Devonian Cheirolepis, a basal ray-fin fish.

Trachinocephalus myops (originally Salmo myops and Saurus myops Forster 1801; 40 cm) is the extant blunt-nosed lizardfish. Traditionally it nests in the clade Synodontidae.

Figure 4. Lepidogalaxias, the salamander fish is not yet tested in the LRT, but the resemblance of this freshwater version of the saltwater lizardfish is apparent.

Figure 3. Lepidogalaxias, the salamander fish is not yet tested in the LRT, but the resemblance of this freshwater version of the saltwater lizardfish is apparent. The bending neck is shown at upper right.

The salamander fish
Lepidogalaxias salamandroides (Mees 1961, 7cm in length) is the extant salamanderfish, the only fish with a neck capable of turning the head nearly at right angles to the torso. Like lungfish, the freshwater salamanderfish is capable of surviving dry seasons by burrowing into the sand.

Molecular studies
consistently recover Lepidogalaxias close to the base of the Telostei where Cheirolepis also nests (when fossils and traits are tested), but the connection has never been made until now (let me know if there is a prior citation I missed).

It is so important to use extant and extinct taxa.
For that reason alone, avoid genetic tests. The second reason is: genetic tests don’t match trait tests over deep time in this and other major clades. The third reason: lots of extant taxa go way, way back phylogenetically.

Figure 3. Subset of the LRT focusing on bony ray fin fish and kin. Here Devonian Cheirolepis nests with extant deep sea Malacosteus.

Figure 4. Subset of the LRT focusing on bony ray fin fish and kin. Here Devonian Cheirolepis nests with extant deep sea Malacosteus. Alongside are Lepidogalaxias and Trachinocephalus.

According to tolweb.org
“Fink (1984) referred to Lepidogalaxias as a ‘potpouri of contradictory and reductive characters’ and placed it in an unresolved trichotomy with the Salmonidae as the sister group of the Neoteleostei. The phylogenetic affinity of this bizarre little fish has been enigmatic since Mees (1961) described it as a galaxiid.”

With about 390 million years between them
it is no wonder that the lizardfish and salamander fish developed traits not seen in Cheirolepis… so did all the other fish that are derived from Cheirolepis! The wonder is, why so few traits evolved to distinguish the extant taxa from the overlooked Devonian sister?


References
Forster JR 1801. in Bloch, ME and Schneider JG editors, Systema Ichthyologiae Iconibus cx Ilustratum. Post obitum auctoris opus inchoatum absolvit, correxit, interpolavit Jo. Gottlob Schneider, Saxo. Berolini. Sumtibus Auctoris Impressum et Bibliopolio Sanderiano Commissum. i-lx + 1-584.
Mees GF 1961. Description of a new fish of the family Galaxiidae from Western Australia. J. Roy. Soc. West. Aust. 44: 33-38.

wiki/Cheirolepis
wiki/Trachinocephalus
wiki/Lepidogalaxias

The primitive arowana (Osteoglossum) enters the LRT

Osteoglossum formosum (Cuvier 1829; up to 2m in length; Figs. 1, 2) is the extant arowana or bonytongue. A facultive air breather, the slow-moving, heavily-scaled arowana feeds on prey just above the water. Fossils extend back to the Late Jurassic. The pelvic fins are reduced to strands. In the large reptile tree (LRT, 1516 taxa, Fig. 3), Osteoglossum nests with Early Jurassic Dapedium.

Figure 1. The arowana, an Amazon River predator, nests with Late Jurassic Dapedium in the LRT.

Figure 1. The arowana, an Amazon River predator, nests with Late Jurassic Dapedium in the LRT. The pink dot indicates the position of the pelvic fins, absent in the skeleton below, present in the specimen above.

I hope the DGS colors added to these fish skulls
make them more accessible for learning. Consider this a starting point on your own academic journey and learn as much as you can on your own.

FIgure 2. Osteoglossum skull with colors added to identify bones.

FIgure 2. Osteoglossum skull with colors added to identify bones.

And if you ever wanted to swim with a Jurassic fish,
you don’t have to start with a drop of blood from a mosquito. Just jump into the Amazon, the Nile or any of the rivers of Borneo and Western Australia. Prior to the split of these exclusively freshwater fish, all these areas were united at Pangaea and Gondwana.

For that matter
the walking catfish (Clarias) will take you back to the Silurian (430 mya), and it will get out of the water to walk with you! Or the headless lancelet (Amphioxous) will take you back to the Cambrian (550mya), about as far back as swimming chordates go.


References
Cuvier GCLD 1829. Le Règne Animal distribué d’apres son organisation, pour servir de base a l’histoire naturelle des animaux et d’introduction a l’anatomie comparée. Avec figures dessinées d’après nature. Nouvelle édition, revue et augmentée. Tome V. Suite et fin des Insectes. Par M. Latreille. Déterville & Crochard, Paris, i-xxiv + 556pp.

The reason the freshwater fish arowana live across the sea

wiki/Dapedium
wiki/Osteoglossum
wiki/Arowana

Triassic Pholidophorus nests with Devonian Strunius

This is another overlooked relationship
assisted by a relabeling of fish skull bones using tetrapod names (Fig. 1).

Figure 1. Pholidophorus in situ + two skull drawings relabeled with tetrapod names.

Figure 1. Pholidophorus in situ + two skull drawings relabeled with tetrapod names.

Pholidophorus sp. (Agassiz 1832; Middle-Late Triassic; 40cm long) was a herring-like fish with primitive ganoid scales and poorly ossified spine. Traditionally considered an early teleost, with large eyes, here it nests with Late Devonian Strunius, but lacks the central process of the tail. Here the skull bones are re-identified with tetrapod labels. The pectoral and pelvic fins were similar in size.

Figure 2. Strunius skull enlarged to show detail. Inset shows the second origin of the dual external naris as the original apparently splits by the addition of a skin bridge creating two openings. Compare to figure 1.

Figure 2. Strunius skull enlarged to show detail. Inset shows the second origin of the dual external naris as the original apparently splits by the addition of a skin bridge creating two openings. Compare to figure 1.

Strunius rolandi (Jessen 1966; originally Glyptomus rolandi Gross 1956; 10 cm in length; Late Devonian) was considered a lobe-fin fish with ray fins. Here it nests with Cheirolepis, a traditional and transitional ray fin fish. The origin of the double naris in this lineage appears here as a split dividing the original single in two. The palate and possible choana are not known.

Figure 4. Subset of the LRT focusing on fish. Note the traditional members of the Holostei do not nest together here largely because they don't look alike, but more like other, more attractive taxa.

Figure 3. Subset of the LRT focusing on fish. Note the traditional members of the Holostei do not nest together here largely because they don’t look alike, but more like other, more attractive taxa.


References
Agassiz L 1832. Untersuchungen über die fossilen Fische der Lias-Formation. Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefaktenkunde, 3, 139–149.
Agassiz JLR 1835. Recherches sur les Poissons fossiles, 5 volumes. Imprimerie de Petitpierre et Prince, Neuchaatel, 1420 pp.
Agassiz JLR 1835. On the fossil fishes of Scotland. Report of the British Association for the Advancement of Science, British Association for the Advancement of Science, Edinburgh.

wiki/Strunius
wiki/Pholidophorus