The Abyssal zone hosts a wide variety of strange, beautiful, ugly and alien looking creatures. Here are a few examples:
Anglerfish is a general term for a group of fish in the order Lophiiformes. They inhabit a variety of oceanic habitats, including the Abyssopelagic. Their name is derived from the fleshy, glowing protrusion on their heads which they use to lure prey. This glowing is a result of symbiosis between the Anglerfish and light-producing bacteria (bioluminescence). However this lure is only present on female fish – anglerfish display extreme sexual dimorphism. Males are only a fraction of the size of females, and do not require a lure due to their stunted digestive system. Instead, they attach themselves to a female, using enzymes to digest her skin, fusing them together permanently. He obtains nutrients from their now shared blood vessels, essentially developing a parasitic lifestyle. Eventually, the male loses most of its organs and devolves into little more than a pair of testes attached to the female, ready to supply sperm at any time. (Vollrath, 1998).
Gulper eels are predatory fish belonging to the family Saccopharyngidae. They are not true eels, and are only named as such based on visual similarities. They are characterised by their extremely large mouths, which enable them to feed on a variety of prey items including crustaceans, fish, and cephalopods. Despite its large mouth, it is thought that gulper eels feed primarily on small crustaceans. These fish host bioluminescent bacteria in their tails, likely to attract prey, although the reason it not entirely clear. Males undergo some morphological changes as they mature, including jaw degeneration and tooth loss. Little is known about the gulper eel’s mating habits as the family hasn’t been studied extensively. (Bertelsen et al., 1989).
Dumbo octopus is the common name for a number of cephalopod species in the genus Grimpoteuthis. They are named so as their large fins resemble elephant ears. They are the deepest known living octopods, inhabiting depths of up to 7500 m (Voss, 1988). These molluscs are carnivores, feeding on various small crustaceans and polychaete worms. Grimpoteuthis grow to an average size of 20 cm, however the largest known specimen was captured at a substantially larger 1.8 m (NOAA, 2009).
The giant amphipod Alicella gigantea is the largest discovered amphipod species, reaching 34 cm in length (Barnard & Ingram, 1986). This amphipod can be found on the lower Abyssal plains – the majority of specimens have been recovered from between 4850-6200 m. They are also known to inhabit hadal depths of up to 7000 m. They are detritivores, eating anything they may come across, even wood. (Jamieson et al., 2013).