Istiophorus platypterus (Shaw 1792 in Shaw and Nodder 1792; 3m) is the extant sailfish descending from Late Cretaceous Pentanogmius. The rostrum is extended, convergent with another fast, open ocean predator, the swordfish, Xiphias. The anterior dorsal fin is larger than the lateral area of the fish itself. Teeth are absent. The pectoral fins are long and slender. The anal fin is divided in two. The vertebral column is composed of relatively few, but large vertebrae.

Alepisaurus ferox (Lowe 1833, 1835a b, 215cm) is the extant lancetfish. Traditionally considered a aulopiform (= lizard fish like Trachinocephalus) here Alepisaurus nests as a swordfish sister without a rostrum sword, but with giant fangs and vestigial pelvic fins. During prey capture the fangs pierce swimming muscles, stopping the struggle. This hermaphrodite taxon can descend more than a mile into deep unlit seas.

Omosudis lowii (Günther 1887; 23cm) is the extant deep sea hammerjaw. Traditionally it is related to lizardfish. In the LRT it is related to Alepisaurus (below) and Xiphias (above). This fast swimmer is a hermaphrodite feeding on squid and fish large enough to stretch out the thin skin of its stomach. In turn, the hammerjaw is preyto lancetfish and tuna. Note the large dentary and palatine fangs.

Traquairius nudus (Lund and Grogan 1997; 13cm; Bear Gulch Formation, 320 mya) was originally considered a ratfish. Here it nests with Omosudis, the deep-sea hammerjaw and it shares some traits with another relative, a juvenile swordfish (above, Xiphias). The long dorsal fin, tiny pelvic lobes, large pectoral fins and long sharp teeth are all notable traits.