Neocyema Erythrosoma - Larval Form

Larval Form

In 1909, Schmidt described a larval form of an eel that had been found in the northeast Atlantic and named it Leptocephalus holti. In 1974, Raju described a similar larval eel from the Pacific Ocean. Both resembled the larva of the bobtail snipe eel Cyema atrum but were morphologically distinct from it. The larvae were transparent and laterally compressed with very long snouts, large eyes, fewer than five intestinal loops and a pattern of lateral pigmentation. The identity of the adult form of these larvae was unknown at the time. After the description of Neocyema erythrosoma in 1978, it was hypothesized that Leptocephalus holti might be its larval form. However, the larvae had lateral pigmentation not found in the adult Neocyema erythrosoma and had been found over 5,000 kilometres (3,100 mi) away from its only known location in the South Atlantic.

In 1996, Smith and Miller reconsidered this matter in the light of 47 other specimens of Leptocephalus holti available to them, mostly from the North Atlantic. They determined that there were three species groups among the larvae and that many of the specimens lacked pigmentation. With the discovery of Neocyema erythrosoma in the Northern Atlantic the distance barrier was also overcome and they considered that there was little doubt that Leptocephalus holti was indeed the larval form of Neocyema erythrosoma.