Grimpoteuthidae Family of Dumbo Octopuses

One Dumbo Octopus of the Grimpoteuthidae Family can be found in this website:

Flapjack Octopus, Grimpoteuthis californiana. A representative example of the Grimpoteuthidae Family of Dumbo Octopuses.

Phylogeny: The Dumbo Octopuses of the Grimpoteuthidae Family are in the phylum Mollusca and in the class Cephalopoda. This class includes squids, octopuses, cuttlefish, and nautiloids. Cephalopods are characterized by having a mantle (body), a head, and a foot that is modified into a series of, at least, eight arms. The arms attach to the head and surround the mouth. The arms may be equipped with suckers, hooks, or cirri. Some will have tentacles in addition to their arms. All cephalopods have three hearts. Two hearts pump blood to the gills, and one heart pumps blood to the rest of the body. Cephalopods have blue blood, because they bind oxygen with hemocyanin. Cephalopods have relatively large brains and complex eyes. Cephalopods can change the color of their skin at will, and very quickly. They do this by nerve controlled chromatophores (pigment sacks in the skin), iridiphores (reflect light to appear iridescent), and leucophores (scatter ambient light).  Cephalopods also have the ability to squirt “ink” into the water to confuse, or hide from, predators. Cephalopods in the Grimpoteuthidae Family are in the order Octopoda. Octopods have eight arms. Their suckers lack muscular stalks and chitinous rings. Their heads attach to their mantle dorsally. They may, or may not, retain a small internal shell, or be equipped with fins. Species in the Grimpoteuthidae Family have a pair of filaments (cirri) around each sucker and are in the suborder Cirrata. The superfamily Opisthoteuthoidea is one of two superfamilies within this suborder, and the Grimpoteuthidae Family is one of three families within this superfamily. The Grimpoteuthidae Family is fairly small with four genera and twenty-two species. The taxonomy of this family is somewhat uncertain as several species are known by only one, or a few, specimens.  Species in the Grimpoteuthidae Family are also commonly called the Cirrate Octopuses,  the Deep-sea Finned Octopuses, the Pelagic Umbrella Octopuses, and Grimpoteuthids.

Morphology: Dumbo Octopuses have soft, sack-like bodies and a vestigial internal shell. Their bodies are short and bell-shaped. The internal shell may be U-shaped, V-shaped or W- shaped and is the attachment point for the muscles that move their strong fins. They have bilateral symmetry and two well-developed eyes. Unlike other octopuses, they lack an ink sack and have an under-developed, or absent, beak. Like all octopuses, they have eight arms, each lined with two rows of suckers. They have a pair of cirri alongside their suction cups, which allow them to detect their prey and move it to their mouths more easily. The arms are much shorter than other octopuses, and are strongly webbed. Viewed from below, when their arms are spread, it looks like an open umbrella. They have a pair of large ear-like fins that protrude from their mantle, resembling the Disney character Dumbo. These fins are located just above the eyes and are used for swimming. Grimpoteuthids are strong swimmers which is attributed to their large fins and webbed arms. Most species in the Grimpoteuthidae Family are less than 30 cm (12 inches) in length but one species reaches a maximum of 1.80 m (5 feet 11 inches) in length.

Habitat and Distribution: Dumbo Octopuses may be found on the seafloor (benthic), swimming just above the sea floor (benthopelagic) or swimming in open water (pelagic). They are the deepest dwelling family of octopuses. They generally live at depths between 200 m (660 feet) and 4000 m (13,000 feet) though some reach depths of 7,000 m (23,000 feet). Dumbo Octopuses are found worldwide in temperate to tropical seas. Because they live at great depths, it is difficult to accurately map their geographic range. Three species from the Grimpoteuthidae Family are found in Mexican waters, though probably more will be discovered.

Reproduction: Dumbo Octopuses are gonochoric (male or female for life). Reproduction is sexual with internal fertilization. During copulation, the male grasps the female and inserts the hectocotylus (A specialized arm that delivers a sperm packet) into the female’s mantle cavity. The female stores the sperm and fertilizes her eggs over time.  Females can carry eggs in various stages of development. The eggs are large and have a hard shell. The eggs are laid in a protected place such as under a rock or shell.

Ecosystem Interactions: Dumbo Octopuses are predatory hunters that probe the seafloor with their small sucker discs and cirri, or they flap their webbed arms to stir up sediment, exposing prey. The octopus will trap prey with its arms and move them to its mouth with its cirri. This limits what the Dumbo Octopus can eat, with them only consuming organisms up to a few millimeters in size. They consume amphipods, bivalves, bristle worms, copepods, isopods and snails. Deep water species have very few predators, which may explain why they lack an ink sac as a defensive mechanism. Shallower water species are eaten by various fishes and marine mammals including dolphins, fur seals, sharks, tunas, and whales.