Blue-ringed octopuses, comprising the genus Hapalochlaena, are four extremely venomous species of octopus that are found in tide pools and coral reefs in the Pacific and Indian oceans, from Japan to Australia. They can be identified by their yellowish skin and characteristic blue and black rings that change color dramatically when the animal is threatened. They eat small crustaceans, including crabs, hermit crabs, shrimp, and other small sea animals.
Mesoplodont whales are 16 species of toothed whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 and 2002, and marine biologists predict the discovery of more species in the future. A new species was described in 2021. They are the most poorly known group of large mammals. The generic name "mesoplodon" comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.
Pyroteuthidae is a family of squids. The family comprises two genera. Species are diurnally mesopelagic, migrating into surface waters during the night. The family is characterised by the tentacles, which have a permanent constriction and bend near the base; and photophores occurring on the tentacles, eyeballs, and viscera. Members reach mantle lengths of 23–50 mm. Paralarvae of the family are common around the Hawaiian Islands, with up to 17% of collected specimens in the area belonging to Pyroteuthidae.
The argonauts are a group of pelagic octopuses. They are also called paper nautili, referring to the paper-thin eggcase that females secrete. This structure lacks the gas-filled chambers present in chambered nautilus shells and is not a true cephalopod shell, but rather an evolutionary innovation unique to the genus. It is used as a brood chamber, and to trap surface air to maintain buoyancy. It was once speculated that argonauts did not manufacture their eggcases but utilized shells abandoned by other organisms, in the manner of hermit crabs. Experiments by pioneering marine biologist Jeanne Villepreux-Power in the early 19th century disproved this hypothesis, as Villepreux-Power successfully reared argonaut young and observed their shells' development.
A hectocotylus is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female. Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male may use it merely as a conduit to the female, analogously to a penis in other animals, or he may wrench it off and present it to the female.
Enteroctopus is an octopus genus whose members are sometimes known as giant octopus.
The greater blue-ringed octopus is one of four species of extremely venomous blue-ringed octopuses belonging to the family Octopodidae. This particular species of blue-ringed octopus is known as one of the most toxic marine animals in the world.
Metasepia pfefferi, also known as the flamboyant cuttlefish, is a species of cuttlefish occurring in tropical Indo-Pacific waters off northern Australia, southern New Guinea, as well as numerous islands of the Philippines, Indonesia and Malaysia. The flesh of this colorful cephalopod contains unique acids, making it unsuitable for consumption.
The common blanket octopus or violet blanket octopus is a large octopus of the family Tremoctopodidae found worldwide in the epipelagic zone of warm seas. The degree of sexual dimorphism in this species is very high, with females growing up to two meters in length, whereas males grow to about 2.4 cm. The first live specimen of a male was not seen until 2002 off the Great Barrier Reef. Individual weights of males and females differ by a factor of about 10,000 and potentially more.
Onychoteuthis is a genus of squid in the family Onychoteuthidae. The type species is Onychoteuthis bergii. While the genus is found worldwide in tropical and subtropical oceans, they can also occur in the North Pacific Ocean. There were previously considered to be four species in the genus but there are now considered to be roughly 10. These squid are frequently observed in the surface waters at night and they are often caught using dipnet at nightlight stations. The young squid are usually the only specimens captured using standard midwater trawls, the older squid are apparently able to avoid the trawls. They can, however be collected from the air as individuals are able to leap high out of the water, sometimes even landing on the deck of a ship.
Pterygioteuthis is a genus of squid in the family Pyroteuthidae. Members are differentiated from the genus Pyroteuthis due to size and head shape. The genus is characterised by the presence of a lidded photophore over each eye.
Pyroteuthis margaritifera, the jewel enope squid, is a species of squid in the family Pyroteuthidae.
Pyroteuthis serrata is a species of squid in the family Pyroteuthidae. It is found north of the tropical convergence in the waters around New Zealand and it does not overlap with Pyroteuthis margaritifera which has a more southerly range.
Melibe is a genus of sea slugs, nudibranchs, marine gastropod mollusks in the family Tethydidae.
Pyroteuthis addolux is a species of squid in the family Pyroteuthidae. It is distinguished from other members of the genus Pyroteuthis by the shape of photophores on the tentacles and the shape of the hectocotylus. The hectocotylus is located on arm IV, containing 10 proximity hooks, and six to 15 suckers at the tip. P. addolux ranges from south of the Hawaiian Islands, to the subantarctic boundary. They exhibit minor geographical variance, as southern specimens are slightly smaller than their northern counterparts. P. addolux is the only member of the genus to occur in the North Pacific, but additional members of the family Pyroteuthidae have also been found. The species has been observed using bioluminescence to reduce its silhouette in dim surrounding light. The type specimen was taken off southern California and described in 1972 by Richard E. Young.
Philiopsis is a genus of often colorful, medium-sized sea slugs, marine opisthobranch gastropod mollusks. These are not nudibranchs; instead they are headshield slugs, in the clade Cephalaspidea.
Loliolus is a genus of squid from the family Loliginidae from the Indo-Pacific region. The genus is divided into two subgenera Loliolus and Nipponololigo. They are small squids of less than 150mm in mantle length which have an expanded tentacular club. This club has 4 series of suckers. The sucker rings have plate-like teeth which are square in shape all around them. The males' hectocotylus has a ventral crest which is created by the fusion of the protective membrane with the ventral series of papillae and this crest completely obscures the conical shape of the papillae. The mantle is rounded posteriorly and lacks the posterior tail-like lobe while the fins are positioned on the rear of the mantle and extend to the posterior tip of the mantle. Their eggs are small and the males' spermatophore has a short cement body. They do not possess photophores. The two subgenera are distinguished by the hectocotylus which in Loliolus encompasses the entire arm and there are no unmodified suckers while in Nipponololigo the arm is only partly hectocotylsed and has normal suckers at its base.
Lolliguncula is a genus of squid from the family Loliginidae from the eastern Pacific and western Atlantic, known as brief squid. The genus is divided into two subgenera Lolliguncula and Loliolopsis. They are rather small squids with a maximum mantle length of 120mm, that inhabit shallow warm seas, although some species have been recorded in areas of low salinity. They are typified by having a short mantle, which is round at the posterior; and fins that are broader than long, but which have no posterior lobes. The males produce spermatophores with a long cement body and they lack a ventral crest on their hectocotylus. Their suckers have square teeth which ring the entire margin or are placed distally. The males do not have enlarged suckers on the left ventral arm. The tentacular club is expanded and contains suckers in four series. The two subgenera differ in the morphology of the hectocotylus.
Ornithoteuthis volatilis, the shiny bird squid, is a squid from the subfamily Ommastrephinae, the flying squids, of the family Ommastrephidae part of the pelagic squid order Oegopsida. It is a tropical and sub-tropical species which is widely distributed in the Indo-Pacific oceans. It is slightly larger than the closely related species Ornithoteuthis antillarum of the Atlantic Ocean.
Sthenoteuthis is a genus of small squids, with two species, part of the subfamily Ommastrephinae within the family Ommastrephidae, the "flying squids". They are the dominant species of flying squid in the world's tropical and subtropical seas and they are commonly seen at the ocean's surface during the night. Their size ranges from mantle lengths of 100 mm to 600 mm.
