Saurichthys

*Saurichthys* is an extinct genus of ray-finned fish that lived on all continents except South America and Antarctica during the Triassic.

## Description

It was elongate and streamlines, mostly being 0.6-1 meters (2-3.3 feet) long. Some species, such as *S. minimahleri* grew to several decimeters, while some could reach a maximum of 1.5 meters (4.9 feet). It was superficially similar to garfish, with dorsal and anal fins opposite one another to the back of the body. This enabled strong swimming, and may have allowed pike-like hunting (high-speed ambush). Its jaws were very long , making 1/3 of the body length and ending in a sharp, beak-like tip. 2-6 longitudinal scale rows are developed, with some species bearing smaller scaled between. The causal fin is defined as abbreviate-diphycercal. The axial skeleton has ossified neural and haemal arches, with the latter having the possibility to develop spines. The neural arches often have spines and other projections, interpreted as prezygapophyses and postzygapophyses. Lacking are ossified centra. The axial skeleton has regionalization (differing bone morphology in different segments. Some species show dedifferentiation in the axial skeleton. Early Triassic species differ most in the elongate postorbital and a, generally, reduced scale cover in both the longitudinal scale rows and individual scales. These do not indicate anagenesis, but rather parallel evolution in different lineages. This is only seen in marine taxa. Late Triassic freshwater species, such as *S. orientalis* or *S. sui*, retain an elongate postorbit and a denser scale cover, suggesting that freshwater were refugia for basal traits.

## Paleoecology

It was apex predator traditionally using ambush techniques via use of sudden darting. Some species may have been subsurface cruisers, such as those in *Sinosaurichthys*. Fossils found within a bolus suggest feeding on *Langobardisaurus* and possible scavenging of corpses[*citation needed*]. The gastrointestinal tract bears similarities with sharks and rays, especially the windings in the spiral valve, which increased surface area for digestion and thus more energy. This reinforces the idea that it was energetic.

### Ontogeny

Gravid females suggest (ovo)-viviparity, being some of the oldest in ray-finned fishes. Internal fertilization is also evidenced by specialized pelvic fin rays, such as *S. calcaratus*, or ventral scales as in *S. curionii* or *S. macrocephalus*, and interpreted as copulatory organs.

## Species

* *S. apicalis*
* *S. breviabdominalis*
* *S. curionii*
* *S. daubreei*
* *S. dawaziensis*
* *S. dianneae*
* *S. dongusensis*
* *S. eximius*
* *S. gigas*
* *S. gracilis*
* *S. grignae*
* *S. gypsophilus*
* *S. hamiltoni*
* *S. hoffmanni*
* *S. huanshenensis*
* *S. irregularis*
* *S. latifrons*
* *S. lepidosteoides*
* *S. macrocephalus*
* *S. majiashanensis*
* *S. minimahleri*
* *S. nepalensis*
* *S. obrutchevi*
* *S. orientalis*
* *S. parvidens*
* *S. piveteaui*
* *S. proximus*
* *S. rieppeli*
* *S. sceltrichensis*
* *S. seefeldensis*
* *S. spinosa*
* *S. stensioi*
* *S. sui*
* *S. tenuirostris*
* *S. tertius*
* *S. ultimus*
* *S. vjuschkovi*
* *S. yangjuanensis*
* *S. yunnanensis*

### Reassigned Species

* *S. acuminatus*
* *S. acutus*
* *S. brevirostris*
* *S. costatus*
* *S. mougeoti*

## Synonyms

* *Belonorhynchus*
* *Brevisaurichthys*
* *Giffonus*
* *Gymnosaurichthys*
* *Ichthyorhynchus*
* *Stylorhynchus*
* *Systolichthys*
* *S. elegans* (=*S. elongatus*)
* *S. intermedius* (=*S. curionii*)
* *S. krambergeri* (=*S. deperditus*)
* *S. robustus* (=*S. macrocephalus*, *S. curionii*, *S. costasquamosus*)
* *S. stoppanii* (=*S. curionii*)

## References

* https://en.wikipedia.org/wiki/Saurichthys
* https://www.tandfonline.com/doi/full/10.1080/08912963.2022.2098023