Deep sea Notothenia joins open sea Coryphaena in the LRT

Notothenia
(Figs. 1, 3), the extant Antarctic yellow belly rock cod,  nests with Coryphaena, the mahi-mahi (Figs. 2, 4), in the large reptile tree (LRT, 1806+ taxa). The two taxa look alike overall… except for the broad-shape of the fins in the former, vs the narrow fins of the latter. And the lack of color and sexual dimorphism in the former. Plus several other relatively, or presently, inconsequential differences you are free to note. 

Figure 1. Notothenia is a deep sea mahi-mahi in the LRT.

Figure 1. Notothenia is a deep sea mahi-mahi in the LRT.

Figure 2. This is where the high forehead of the male mahi-mahi (Corphaena) comes from, one of the very few fish with a frontal crest.

Figure 2. This is where the high forehead of the male mahi-mahi (Corphaena) comes from, one of the very few fish with a frontal crest.

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

Figure 3. Notothenia is a Coryphaena sister of the deepest oceans. Here it converges with the wolf eel, Anarhichas.

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

Figure 4. Mahi-mahi (Coryphaena) mounted as if in vivo.

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.

Coryphaena hippurus (Linneaus 1758; 1.5m length) is the extant open seas predator mahi-mahi or dolphinfish, here related to the similar, but deeper Notothenia. 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 x. Rayfin fish cladogram. This one represents the latest subset of the LRT.

Figure x. Rayfin fish cladogram. This one represents the latest subset of the LRT.

The yellow belly rock cod nests with the mahi-mahi
and THEY nest close to the Atlantic cod, Gadus (Fig. 5), a taxon added to the LRT earlier here. I guess yellow-belly rock cod sounds better than yellow-belly mahi-mahi.

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

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

 

“The task is…not so much to see what no one has yet seen; but to think what nobody has yet thought, about that which everybody sees.” ~ Erwin Schrödinger


References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Richardson J 1844. Ichthyology of the voyage of H.M.S. Erebus & Terror. In: Reptiles, fishes, Crustacea, insects, Mollusca, Longman, Brown,London.: 1-16.

wiki/Mahi-mahi
wiki/Notothenia_coriiceps

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