Coryphaenoides, the deep-sea rat-tail, is a deep sea cod

No controversy here
as the deep sea rat tail, Coryphaenoides carapinus, enters the large reptile tree (LRT, 1814 taxa) between  the cod, Gadus (Fig. 3) and the mahi-mahi, Coryphaena (Fig. 2) plus its Antarctic relative, Notothenia (Fig. 4).

Figure 1. The rat tail Coryphaenoides, is close to the cod, Gadus, in the LRT.

Figure 1. The rat tail Coryphaenoides, is close to the cod, Gadus, in the LRT.

Coryphaenoides carapinus (Gunnerus 1765) is the extant rat tail, a deep sea fish close to Gadus with dorsal fins, anal fins and caudal fins merged into a straight tail. Like some sharks, the nasal extends beyond the premaxilla. The circumorbital series is robust. The parietals are unknown in this image.

FIgure 1. Mahi-mahi (Coryphaena) mounted as if in vivo.

Figure 2. Mahi-mahi (Coryphaena) mounted as if in vivo.

Coryphaena hippurus (Linneaus 1758; 1.5m length) is the extant open seas predator mahi-mahi or dolphinfish, here related to the similar, but deeper sea Notothenia (Fig. 4). The dorsal fin starts at the skull. The caudal fin is deeply forked. The teeth are needle-like. Males have a tall fleshy forehead supported by a bony crest. A smaller-crested female is also shown above.

Figure 5. Atlantic cod, Gadus morhua, in lateral view.

Figure 3. Atlantic cod, Gadus morhua, in lateral view.

Gadus morhua (Linneaus 1758) is the Atlantic cod, nesting between the mahi-mahi (Coryphaena) and the cobia, Rachycentron. The anal fin is split in two. The chin has a barbel. The postparietal forms a long crest that divides the parietal. The naris is divided in two by the lacrimal. An antnarial opening precedes the naris. Note the elongate intertemporal and hyomandibular.

Figure 3. Notothenia is a Coryphaena sister of the deepest oceans.

Figure 4. Notothenia is a Coryphaena sister of the deepest oceans.

Notothenia coriiceps (Richardson 1844; 50cm) is the extant Antarctic yellowbelly rockcod. It lacks a swim bladder and the bones are dense, accounting for its reduced buoyancy. The body is adapted to sub freezing temperatures. Here it nests with the mahi-mahi, Corphaena (above), not with traditional perch.


 

References
Gunnerus JE 1765. Efterretning om Berglaxen, en rar Norsk fisk, som kunde kaldes: Coryphaenoides rupestris. Det Trondhiemske Selskabs Skrifter 3: 50-58.
Linnaeus C von 1758.
Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Gadus_Atlantic_cod
wiki/Coryphaenoides
wiki/Notothenia_coriiceps
wiki/Mahi-mahi

 

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