User:Oliviascott99/Octopus tetricus

Octopus tetricus
This article is about the species Octopus tetricus of the class cephalopoda and in the family Octopodidae.

Octopus tetricus is one of the many species in the order Octopoda and family Octopodidae. (insert beginning sentence of already existing text). O. tetricus is similar to O. vulgaris, a commercially prized species. The two species are similar in size, morphology and behavior. Another common name of this species is the gloomy octopus.

Distribution
Octopus tetricus was originally discovered in New South Wales and was also found along the eastern Australian coastline. It's habitats range from Eden in southern New South Wales to Moreton Bay in southern Queensland. (insert last sentence of distribution). The similar subspecies found is also referred to as O. tetricus but it is referred to as the common Perth octopus. Its range in Western Australia includes Esperance to Shark Bay. These two octopuses are very closely related and have similar behavioral, morphological, and functional traits so they have been categorized under O. tetricus, but the Perth octopus was categorized under O. (cf) tetricus to distinguish the two.

Anatomy and morphology
(This is where the description comes into play.) O. tetricus has eight limbs, two eyes, and a beak. There is a second species of O. tetricus called O. (cf) tetricus and it is found in West Australia. This second species differs morphologically and genetically from O. tetricus.

Reproduction and Growth
The reproductive cycle of females is tied to seasonal changes, similar to many other species. Females reach maturity around Australia's spring and summer seasons in order to mate and lay eggs. During the mating process the male O. tetricus passes spermatophores to the female in two different ways. The male either wraps his arms and web around the female's mantle or reaches his mating arm from a distance and inserts it into the female's mantle. Spermatophores are released from the male's "terminal organ", moved by the male's oral suckers, and then the spermatophores are inserted into the female's oviduct.

Octopus tetricus start out as eggs that are laid in large numbers in the octopuses nest. The eggs are normally glued to the rock or substrate at the top of the den created by the female octopus. The female usually lays her eggs over several nights in a string formation. The size and number of strings of eggs usually depends on how large the female is and can have between 60 to 200 egg strings. The female then guards the eggs until they hatch. Female O. tetricus have also been known to store viable spermatozoa for up to 114 days. The amount of time embryonic development takes varies with water temperature, and newly hatched O. tetricus larvae are about 2.5 mm long and 1.1mm wide. These larvae go through a stage called the paralarval stage where they are considered planktonic, or free floating, organisms before they settle to the bottom and grow large enough to hunt for their food. This stage may last around 35-60 days.

Temperature plays a key role in growth of this octopus species. With a good food supply, octopuses that reside in areas with a cooler water temperature tend to grow slower during the key growth phase and when they reach maturity they are generally larger than octopuses that are found in warmer water temperatures. Females are found to mature at a slower rate and become larger than male O. tetricus.

Lifespan
Adult O. tetricus is observed to have a relatively small body size and a lifespan of approximately 11 months. Female O. tetricus rarely eat or sleep during the protection of the nest and die shortly after the eggs hatch. (insert info about female cannibalising males)

Habitat
(use first sentence of habitat paragraph) O. tetricus alter their habitats by digging out dens and using remains from prey, including but not limited to shells. It is very common for scallop beds to be found in close proximity to the excavated dens. The scallops serve as a food source and their shells are part of the shell beds built. This species of octopus is considered to be an ecosystem engineer. This means that the way they create their habitats influences and builds an ecosystem around their dwellings. The shell beds that are created around the excavated dens attract hermit crabs and fish due to the various hiding places created. Small fish and other small prey species attract larger species and the cycle builds, creating an ecosystem. A solid object serves as a good den can be the start of a new settlement for O.tetricus. Studies show that O. tetricus has higher populations in patch reef habitats than broken reef habitats, and were scarcely found on flat reefs. Adult O. tetricus were also found to occupy coastal reefs in the summer and then disappear around the second week of April, which is the second week of autumn in Australia. Shelters serve a vital role in octopus ecology. The species is generally known to be solitary, but complex social behaviors have been observed by scientists.

Social behavior and mating
Scientists have observed many different behaviors exhibited by O. tetricus including, signaling, mating, mate defense, and aggression. Some have even observed an octopus evicting another from it's den. Occasionally this aggressive behavior led to physical altercations between octopuses. (last two sentences of first paragraph fit here)

Observation of mating behaviors has revealed that O. tetricus females have a stronger precopulatory preference for males that have longer mating appendages, or ligulae. Both female and male octopuses mate multiple times throughout a mating season. Female octopuses are able to accept multiple spermatophores from males but they only produce one brood of eggs at the end of a mating season.