# Engaeus orramakunna

Engaeus orramakunna, the Mount Arthur burrowing crayfish, is a species of crayfish in the family Parastacidae. It is endemic to Australia. It is a small to semi-medium sized burrowing crayfish that specialises in creating large burrows and subterrainan living.

## Etymology

Engaeus orramakunna, the genus Engaeus draws it's name from Greek. Engaeus roughly translates to "Earth dwelling" by furthur breaking it down; en (ἐν) means "in" and geaus (γαῖα) means "dirt"/ "land," or it can be a call back to the ancient Greek Goddess of the Earth "Gaia".
Orramakunna can be found in a historic Aboriginal Tasmanian vocabulary document. The word itself has been listed as a name in (Palawa Kani) for a specific district for the Piper's River District, which can be related to the Pipers River which flows under Mount Arthur.

## Description

Like most burrowing crayfish of the genus Engaeus, there average length of the animal can range from 7 to 10 centimeters. Their bodies are narrow with a reduced tail, due to their evolution from a free swimming organism to a terrestrial organism. The claws are able to open vertically, an adaptation to circumvent the difficulty of living underground and in confined spaces with large claws.
The colour morphs are usually found in a striking orange hint, although there have been sightings of brown morphs. The Mount Arthur burrowing crayfish can be distinguished from the rest of the Engaeus genus by the lack of a transverse suture across the outer part of the tail fan.

## Distribution

The distribution of the Mount Arthur burrowing crayfish can be found in the north-eastern part of Tasmania, centered around Mount Arthur. The range extends up north to Nabowla, to the east near South Springfield and to the west near Lilydale. The species' southern boundry has not been fully studied and mapped out, however there have been observations of individuals of the species near Launceston to the southwest.

## Habitat and Ecology

Like the rest of the Engeaus, Engaeus orramakunna can be found in moist and wet dirt that are perfect for burrowing and tunneling. The species prefers earth with high moisture and clay content, the animals would dig deep and complex burrows across multiple generations. They would prefer building burrows close to the underground water table as opposed to near above ground water bodies such as streams, rivers or lakes. The burrows created by these animals have distinct chimneys made up of dirt pellets.
The Mount Arthur burrowing crayfish can be found in a myriad of different ecosystems and habitats, possible due to Tasmania's rugged and diverse terrain and geology. There have been sightings and observations in Eucalypt forests, undisturbed rainforests, open pastures, cattle-trampled pastures and in roadside drains.
The burrows of the species are commonly found alongside multiple plant species such as; Dicksonia Antartica (soft tree fern), Leptospermum (tea-trees), Melaleuca (paperbacks) and Eucalypt species, Pinus radiata (radiata pines) and Atherosperma moschatum (southern sassafrass).
The life history, the breeding season starts in late winter. Female individuals of the Mount Arthur burrowing crayfish were discovered carrying undifferentiated eggs in late July, early August, late October and early November. And some males have been found living in the same burrows as the observed females.

## Threats and Conservation

The Mount Arthur burrowing crayfish faces several threats, including habitat loss from agriculture, forestry, and urban development, which destroy its burrows and reduce soil moisture. Logging and forestry practices disrupt habitats by altering hydrology and increasing erosion.
Climate change further threatens the species by reducing rainfall and increasing temperatures, which dry out burrows. Pollution from agricultural runoff and industrial contaminants harms both crayfish and their environment. Recreational activities such as hiking and off-roading damage burrows and degrade habitats.
Conservation efforts include habitat protection through reserves and land management, and sustainable forestry practices like buffer zones and reduced-impact logging. Ongoing monitoring and research track population trends and guide strategies, while community awareness programs promote habitat protection. The species benefits from legal protection under the EPBC Act and Tasmania’s Threatened Species Protection Act, ensuring conservation measures are enforced. Mitigation of climate change effects and pollution control strategies are also in place to protect water quality and ensure the species’ survival.