The deep ocean holds many mysteries, and among its most intriguing inhabitants are vampyropods. These enigmatic creatures thrive in the abyssal plains, a realm of perpetual darkness and immense pressure. Their unique biology and ancient lineage offer a glimpse into the diverse evolutionary paths taken by life in Earth’s most extreme environments.
What are Vampyropods?
Vampyropods are an order of cephalopods known as Vampyromorphida, which includes the sole living species, Vampyroteuthis infernalis, commonly referred to as the Vampire Squid, alongside numerous extinct relatives. They are distinctly classified within the broader cephalopod family, separate from true squids and octopuses, though they share characteristics with both. The Vampire Squid’s closest living relatives are octopods, despite its common name. This ancient lineage has earned the Vampire Squid the designation of a “living fossil” due to its relatively unchanged form.
The Modern Vampyroteuthis infernalis: Anatomy and Habitat
The Vampire Squid, Vampyroteuthis infernalis, is a small cephalopod, reaching up to 28 to 30 centimeters (around one foot) in length. Its gelatinous body varies in color from deep black to a pale reddish hue. A distinctive feature is the webbing of skin that connects its eight arms, giving it a cloak-like appearance, which inspired its name.
Its large eyes are among the largest in the animal kingdom relative to body size, appearing red or blue. Along each of its eight arms are rows of fleshy spines, or cirri, though suckers are only found on the halves of the arms farthest from the body. Unique to this species are two long, retractable filaments located between the first two pairs of arms on its dorsal side, which can extend well beyond the animal’s total length and retract into pockets within its web. This deep-sea inhabitant prefers aphotic (lightless) depths, residing between 600 to 3,000 meters (2,000 to 10,000 feet). Within this range, it frequently occupies the oxygen minimum zone (OMZ), where oxygen saturation can be as low as 3-5%, and water temperatures range from 2 to 6 degrees Celsius.
Deep-Sea Survival: Unique Adaptations and Behavior
The Vampire Squid has adaptations for survival in the extreme conditions of the deep sea. Unlike many cephalopods, it lacks an ink sac for defense. Instead, when threatened, it adopts a unique “pineapple” or “inside-out” defensive posture, curling its arms outwards and wrapping them around its body. This action inverts its web, exposing the spiny cirri on its tentacles and making it appear larger and more intimidating.
Its bioluminescent capabilities are another adaptation. The Vampire Squid is nearly entirely covered in photophores, which are light-producing organs capable of emitting disorienting flashes of light for several minutes. It can also eject a sticky cloud of glowing mucus from its arm tips, which can confuse or deter predators, allowing the squid to escape. Its feeding strategy is unusual: it is a detritivore, consuming “marine snow”—a mixture of dead plankton, fecal matter, and other organic debris that drifts down from shallower waters. It uses its two unique retractile filaments to capture these particles.
To thrive in the low-oxygen environment, Vampyroteuthis infernalis has the lowest mass-specific metabolic rate among deep-sea cephalopods. Its blue, copper-based blood, hemocyanin, efficiently binds and transports oxygen, and its gills possess an especially large surface area to aid in oxygen absorption.
Ancient Lineage: Fossil Vampyropods
The fossil record of vampyropods provides insights into their ancient origins within cephalopods. Fossil evidence indicates that vampyropods originated in the Paleozoic era, significantly extending their known stratigraphic range by approximately 81.9 million years. One notable discovery is Syllipsimopodi bideni, identified from an exceptionally preserved fossil found in the Mississippian Bear Gulch Lagerstätte in Montana, USA. This specimen, dating back approximately 328 million years, is the oldest definitive vampyropod and is unique for possessing ten functional arms with suckers, challenging previous hypotheses about their evolution and suggesting that their common ancestor also had ten arms.
Other extinct species, such as Muensterella and Vampyronassa, also provide insight into this ancient group. Vampyronassa rhodanica, found in Middle Jurassic fossils, shares characteristics with the modern Vampire Squid, such as the absence of an ink sac. These fossils reveal how early vampyropods began to diverge from other cephalopod lines, characterized by the loss of the chambered phragmocone and primordial rostrum, traits retained in other ancient cephalopods.