Surprise! The longnose gar (Lepisosteus) enters the LRT with sticklebacks and seahorses

Gars are traditionally considered
‘primitive bony fish.’

According to Wikipedia,
(citing the Betancur et al. 2017 genomic study; Fig. 1) Lepisosteiformes (gars and kin), like the long-nose gar (Lepisosteus), should nest with the very basal Amiiformes (bowfins, like Amia). Prior genomic studies in birds, mammals, etc., have failed to match trait studies that recovered a gradual accumulation of derived traits here. Unfortunately, and once again, genomic studies fail to match trait studies, this time in fish.

Betancur et al. 2017 reported,
“The first explicit phylogenetic classification of bony fishes was published in 2013, based on a comprehensive molecular phylogeny (www.deepfin.org). We here update the first version of that classification by incorporating the most recent phylogenetic results. We also highlight cases were morphological support exist for the groups being classified. The classification presented in this study represents, unlike any other, the most up-to-date hypothesis of the Tree of Life of fishes.”

After phylogenetic analysis
in the large reptile tree (LRT, 1505 taxa, subset Fig. 2), the longnose gar, Lepisosteus nested at a much more derived node, with the equally slow-moving sticklebacks (Gaterosteus), pipefish and seahorses (Hippocampus, Fig. 5).

Lepidosteus osseus (also Lepisosteus Lacepéde 1803) is the extant longnose gar. Note the jaw joint is in front of the orbit, similar to the stickleback, Gasterosteus. The longest teeth arise from the inside the of jaws, long palatal bones (vomer, palatine, ectoptergoid). The extrernal rostrum is lined by the elongate premaxilla. Distinct from Amia, the gar maxilla is absent. The traditional jugal is the lacrimal.

Wikipedia reports,
“Fossils [of gars] have been found in Africa, Asia, Europe, North America, and South America dating back 100 million years” Gars have elongated bodies that are heavily armored with ganoid scales, Unusually, their vascularised swim bladders can function as lungs, and most gars surface periodically to take a gulp of air.

So, how did the Betancur et al. study fail?

1. Taxon exclusion. They did not include sharks, ratfish and placoderms for reasons that seem traditionally obvious, but falsified by the wider gamut LRT.
2. Failure to check results for physical similarity in sister taxa.
3. Belief (= faith) in the ability of genes/molecules to reveal phylogenetic relationships among deep time vertebrates. The LRT invalidates gene studies, producing sister taxa that share more physical traits and therefore look similar to one another, echoing evolutionary events.

In science,
an experiment should be repeatable if valid. The LRT tests phylogenetic analyses based on trait and genes with a wide gamut of extant and fossil taxa to cover all possible nestings.

I was not able to confirm the traditional nesting of gars
with the distinctively different bowfins, but was able to nest gars with the overall similar sticklebacks and sea horses, all sharing an armored body, a jaw joint anterior to the orbit, a vestigial or absent maxilla, an absent squamosal, jugal and postorbital, and often (but not universally) a long rostrum, along with a suite of other traits.

References
Betancur R, et al. (7 co-authors) 2017. Phylogenetic classification of bony fishes. BMC Evolutionary Biology BMC series – 201717:162 pp.  online here

https://en.wikipedia.org/wiki/Osteichthyes
https://en.wikipedia.org/wiki/Euteleostomi
https://en.wikipedia.org/wiki/Actinopterygii
https://en.wikipedia.org/wiki/Chondrostei
https://en.wikipedia.org/wiki/Gar