Goblin Shark — 1 species
- snout with a greatly elongated, flattened projection
- jaws highly protrusible
- precaudal pits absent
- eyes small
- anal fin broadly rounded
- upper lobe of caudal fin long (about half the length of the body), lower lobe not developed
- scattered distribution in eastern and western Atlantic (Surinam, French Guiana), South Africa, and western Pacific; most specimens from Japanese waters
As depicted in most shark books, the Goblin Shark (Mitsukurina owstoni) looks quite unlike any other lamnoid — more like a snaggle-toothed, beaked gargoyle with a carpenters' trowel projecting forward from its 'forehead'. But this unwieldy headgear is actually an artifact of the goblin shark's extremely protrusile jaws.
With its jaws retracted, the Goblin Shark looks considerably less bizarre — resembling an elongate ragged-tooth (Odontaspididae) or Sandtiger Shark (Carchariidae) with an unusually long, flat snout and rounded fins. And therein lies a clue to the Goblin Shark's relationship to other lamnoids. The front teeth of the Goblin Shark are dagger-like and smooth-edged, similar to those of the ragged-tooth and Sandtiger sharks, but lack the well-developed basal cusplets characteristic of these species. The Goblin Shark's rear teeth, however, are modified for crushing, quite unlike those of ragged-tooth sharks but similar to the rear teeth of the Sandtiger. The Goblin Shark's lineage extends farther back than any other lamnoid — some 124 to 112 million years ago — represented in the fossil record by Anomotodon principalis, whose mineralized teeth are similar in form to those of its living descendent.
The 1997 mtDNA study by Naylor et al. suggests that the Goblin Shark's ancestor diverged from the group's common ancestor earlier than that of any extant species. The fossil record and genetic data therefore both support Compagno's hypothesis that the Goblin Shark represents the primitive sister taxon to all other lamnoids. If this interpretation is correct, then the Goblin Shark apparently became specialized relatively early in its evolutionary career.