Odd Gonorhynchus and Late Cretaceous Sapperichthys now nest basal to European and garden eels in the LRT, derived from sailfish ancestors according to the LRT

Odd mouth parts
were difficult to understand and score in Late Cretaceous Sapperichthys and extant Gonorhynchus (Figs 1,2). Finally some insight, courtesy of the LRT and a similar enough taxon, Late Cretaceous Pentanogmius (Fig 1), a sailfish ancestor.

BTW, that new insight does not resolve the riddle of the odd mouth parts, because related taxa (Fig 1) do not have a hint of oddity in their lower jaws.

Earlier such odd mouth parts linked Gonorhynchus to sturgeons. Now there’s a better link.

Figure 1. Sapperichthys and Gonorhynchus now nest close to Late Cretaceous Pentanogmius, a basal marlin/swordfish in the LRT. ” data-image-caption=”

Figure 1. Sapperichthys and Gonorhynchus now nest close to Late Cretaceous Pentanogmius, a basal marlin/swordfish in the LRT.

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2023/12/sapperichthys.face588.jpg?w=222″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2023/12/sapperichthys.face588.jpg?w=584″ src=”https://pterosaurheresies.files.wordpress.com/2023/12/sapperichthys.face588.jpg” alt=”Figure 1. Sapperichthys and Gonorhynchus now nest close to Late Cretaceous Pentanogmius, a basal marlin/swordfish in the LRT. ” class=”wp-image-83288″ />

Gonorhynchus, the beaked salmon, is the real problem.
Based on comparative anatomy, the premaxilla is now in five parts. The dentary in two parts for each side of the jaw. How the jaw works is still unknown. Someday a YouTbe

Figure 2. Gonorhynchus has the oddest mouth in the LRT. I do not know how it works. The premaxilla here split into five parts and the dentary here split into two parts bear only vague semblance to Pentangmius in figure 1. But the rest of the skull is similar enough to nest close to one another. ” data-image-caption=”

Figure 2. Gonorhynchus has the oddest mouth in the LRT. I do not know how it works. The premaxilla here split into five parts and the dentary here split into two parts bear only vague semblance to Pentangmius in figure 1. But the rest of the skull is similar enough to nest close to one another.

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2023/12/gonorhynchus588.jpg?w=279″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2023/12/gonorhynchus588.jpg?w=584″ src=”https://pterosaurheresies.files.wordpress.com/2023/12/gonorhynchus588.jpg” alt=”Figure 2. Gonorhynchus has the oddest mouth in the LRT. I do not know how it works. The premaxilla here split into five parts and the dentary here split into two parts bear only vague semblance to Pentangmius in figure 1. But the rest of the skull is similar enough to nest close to one another. ” class=”wp-image-83291″ />

A YouTube video
(below) shows Gonoryhnchus (aka Gonorynchus) swimming with flicks of its tail and the pectoral fins held nearly motionless, as in swordfish and sailfish.

Gonorynchus gonorynchus
(originally Cyprinus gonorynchus Linneaus 1766; 60 cm) has several common names including beaked salmon, ratfish, mousefish, sand eel, sand fish and shark whiting. The circumorbital bones are absent. The jaw elements lack teeth. This nocturnal fish eats zooplankton and buried invertebrates, then buries itself during the day.

Gregory 1933 reported, “It has an elongate cylindrical body and a sturgeon-like head with a pointed snout, a small inferiorly-placed mouth and a rostral barbel. The body and head are covered with small spiny scales.” Here several bones labeled in Gregory 1933 are relabeled according to Pentanogmius and European eel (Anguilla) homologs. A notochord pierces the well-ossified abdominal vertebrae. The torso is squarish in cross-section. The pectoral fins are essentially immobile.

A postorbital is absent. The prefrontal is separated from the postfrontal. The tail is diphycercal. The prefrontal sits atop a segment of the postfrontal.

Sapperichthys chiapanensis
(Amaral et al 2013, Cenomian, Late Cretaceous, 90mya, 15 cm est length) is an early gonorynchid, derived from Late Cretaceous Pentangmius and basal to European eels, Fossil in situ shown actual size.

This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation so I can promote it here.

References
Amaral CRL, Alvarado-Ortega J and Briot PM 2013. Sapperichthys gen. nov., a new gonorynchid from the Cenomanian of Chiapas, Mexico. In: Mesozoic Fishes 5 – Global Diversity and Evolution, Arratia, Schultze and Wilson (eds.): 305–323. by Verlag Dr. Friedrich Pfeil, München, Germany – ISBN 978-3-89937-159-8
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/Gonorynchus – wiki/Gonorynchus_gonorynchus
wiki/Sapperichthys – not yet posted
wiki/Gonorynchiformes