The goblin shark (Mitsukurina) enters the LRT

Revised December 7, 2020
with a new nesting of Mitsukurina closer to paddlefish than to guitarfish (Fig. x) despite the presence of gill slits on Mitsukurina and gill covers on paddlefish. That would be “Pulling a Larry Martin” as all other traits support the new relationship.

Figure 4. Subset of the LRT focusing on sharks.

Figure x. Subset of the LRT focusing on sharks.

 

Often hailed as ‘the most bizarre shark’,
the goblin shark, Mitsukurina owstoni (Jordan 1898; Figs. 1, 2) nests with the paddlefish  (Polyodon) in the large reptile tree (LRT, 1710+ taxa then, 1772 taxa now).

Figure 1. The skull of the goblin shark, Mitsukurina.

Figure 1. The skull of the goblin shark, Mitsukurina. Red arrow points to naris. The extended nasal region is full of ampullae that sense electrical activity produced by prey twitching muscles while hiding in the sea floor.

Figure 2. Classic diagram of the goblin shark, Mitsukurina.

Figure 2. Classic diagram of the goblin shark, Mitsukurina.

Mitsukurina owstoni (Jordan 1898; 3-4+m long) is the extant goblin shark, a dead end form close to paddlefish, converging on sharks with regard to the gill slits. This is a sluggish swimmer feeding on sea floor prey, sensing their electrical fields, snatching them with protrusible jaws, (as in paddlefish).

FIgure 3. Scapanorhynchus, and Early Cretacous goblin shark.

FIgure 3. Scapanorhynchus, and Early Cretacous goblin shark.

Scapanorhynchus lewisii (Davis 1887; 65cm to 3m long; Early Cretaceous) is a fossil goblin shark.

Figure 2. Rhinobatos, the guitarfish, and Rhina the bowhead guitarfish, are transitional to skates and rays, but not mantas. Note the ventral mouth and pectoral fins extending anterior to the orbits.

Figure 4. Rhinobatos, the guitarfish, and Rhina the bowhead guitarfish, are transitional to skates and rays, but not mantas. Note the ventral mouth and pectoral fins extending anterior to the orbits.

Rhinobatos rhinobatos (Linneaus 1758; up to 1.47m) is the extant common guitarfish, a transitional taxon between sharks and skates. The mouth and gills are below the pectoral fins that extend forward anterior to the eyes, which rise to the top of the skull.

Rhina anclystoma (Bloch and Schneider 1801) is a type of guitarfish. Still waiting for skull data to score this fish.


References
Bloch MC and Schneider JG 1891. Systema anclystoma.
|Davis JW 1887. The fossil fishes of the chalk of Mount Lebanon, in Syria. Scientific Transactions of the Royal Dublin Society, 2 (3): 457–636, pl. 14–38.
Jordan DS 1898. Description of a species of fish (Mitsukurina owstoni) from Japan, the type of a distinct family of lamnoid sharks. Proceedings of the California Academy of Sciences, Zoology. Series 3. 1 (6):199–204.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Common_guitarfish
wiki/Mitsukurina
wiki/Goblin_shark
wiki/Scapanorhynchus

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