Our Observation of the Week is this Paridotea ungulata isopod, seen in Australia by @moth_nut!
Currently living in Tasmania and working with the Australian National University and researching habitat suitability, threats, and effective management strategies for some of Australia’s most endangered birds, Tom Hunt’s childhood was spent in the Adelaide Hills of South Australia.
Surrounded by bushland and birds, I have been a keen nature lover and photographer for as long as I can remember. That passion eventually shaped my career, taking me across Australia as an ecologist working on conservation projects.
My work is driven by a desire to help, in some small way, to reverse Australia’s alarming extinction rates and protect the wildlife that makes this country so special. As such, I have a particular interest in threatened species monitoring and management. After studying at The University of Adelaide, I spent over a decade working on conservation and restoration projects in South Australia, Victoria, and New South Wales. This included researching endangered mallee birds and reintroducing locally extinct mammals through the Wild Deserts project.
Now that he’s in Tasmania, Tom’s begun to explore coastal habitats in earnest.
My partner and I soon found ourselves spending more time exploring the coastline – beachcombing, rockpooling, snorkelling, and diving – using iNaturalist to log and learn about the things we saw. One of our most exciting discoveries came after I saw a few iNat observations of a beautiful sea centipede (Paridotea ungulata) in my local marine reserve at Tinderbox – a rugged peninsula in southern Tasmania fringed by rocky reefs and cold-water kelp forests. I had no idea sea centipedes even existed until I found these local records!
One weekend as we were exploring a shallow bay on the Tinderbox Peninsula, we spotted something bright green attached to a floating piece of Giant Kelp . Intrigued, I swam over for a closer look – and to my delight, it was a Paridotea ungulata. Its vibrant, electric-green body clung tightly to the kelp with its specialised grasping legs. I brought it to shore for a quick photograph before releasing it back into the water. Watching it swim away using its valve-like uropod to propel itself in a rippling motion – remarkably reminiscent of a writhing centipede – was mesmerising.
As an ecologist, few things are as thrilling as encountering a species from a completely new taxonomic group, even more so when you have been given the background knowledge from a source like iNaturalist to make you realise what a special creature it is. My fascination with marine life continues to grow, and I’ll be keeping an eye out for more sea centipedes amongst the host of other exciting finds that await us here.
Isopods like the one seen here belong to the suborder Valvifera, marine isopods commonly known as valvetails due to their valve-like uropods. You can often find them clinging to kelp and other objects if you’re doing some coastal exploration.
Tom (above) joined iNat almost exactly five years ago and wrote some wonderful paragraphs about it to me, so I’ll just present them here in full.
As a passionate wildlife observer, I use iNaturalist to document the species I encounter – whether at home, on hikes, or while working in the field. For species I’m familiar with, it’s rewarding to log observations in less-visited areas, contributing valuable distribution data. For those I don’t recognise, iNaturalist is like carrying the world’s most comprehensive field guide in my pocket, helping me identify species and discover what I might encounter on my next adventure. It has also helped spark an interest in so many more taxa, from moths and mantises to peas and Proteaceae!
As a researcher, iNaturalist has been an invaluable tool for tracking species distributions and uncovering unusual records. But just as importantly, it allows me to give back – helping others identify wildlife using my own ecological knowledge, particularly given that these contribute to publicly available datasets I frequently use in my work.
One of the most powerful aspects of iNaturalist is its ability to spark curiosity and fuel deeper exploration. The natural world can feel overwhelming – many people don’t know where to begin if they can’t already identify species; the trick is simply having a starting point. Learning a few common species creates a foundation for recognising what’s unfamiliar, making it easier to notice patterns, compare features, and find more information. Traditionally, this kind of knowledge required access to field guides, a mentor, or higher-education study – resources that aren’t always available for many people, especially for lesser-known taxa, or in remote and less-studied regions.
iNaturalist changes this. It’s a free, dynamic, and constantly growing resource that offers detailed, location-based species lists, computer-vision powered ID suggestions, and direct connections to experts. It provides instant feedback and a fast track to deeper engagement with the natural world – across all observable taxa.
In this way, I think iNaturalist is truly game-changing. It doesn’t replace field guides, taxonomic expertise, or academic research, but it enhances them. By creating a two-way exchange of knowledge between citizen scientists and experts, it also accelerates research, conservation, and public interest in nature. In my view, iNaturalist is one of the most revolutionary tools for connecting people with the natural world – and it’s exciting to know its potential is only increasing.
(Photo of Tom by Marike Oliphant)
- iNat staff member and marine ecologist @kestrel tells me that with valvetails, “their color is often based on what they've been eating.” She sent me to this observation which contains three individuals of the same species!
- fish isopods are another type of marine isopod, take a look at two previous fish isopod Observations of the Week, one by @vasilis_stergios, another by @oryzias!
