This is the twenty-eighth entry in an ongoing monthly (or almost monthly!) series profiling the amazing identifiers of iNaturalist.

Alexis Tinker-Tsavalas is a young naturalist who first crossed my radar way back in early 2020, when I chose a moss observation of his as Observation of the Day. Since then he’s become a phenomenal macro photographer who has his own very helpful YouTube channel, was named the Young Wildlife Photographer of the Year in 2024 by the Natural History Museum, and added over 100k identifications on iNaturalist! 

Half Greek and half Canadian, Alexis was born in Germany and has lived there his entire life. 

I spent a lot of time outside in nature as a little kid, and with several close relatives being biologists that scientific view on the natural world was always present for me. I started birdwatching around age 7, and in the 11 years or so since, nature observation in general has become a big part of my life. In the last 5 years, especially through the pandemic, my interest has shifted more toward smaller arthropods, though I am fascinated by all kinds of wildlife.

Alexis’s identification habits have followed a similar trajectory: 

I used to mostly identify European bird observations, but stopped a few years ago as my focus shifted away from birding. In the last few years I have become fascinated by Springtails, and they account for the vast majority of my IDs since then. While I don't have much time for identifying these days, I try and go through recent observations whenever I have the chance and help out on any observations I've been tagged in. [Alexis is among the top identifiers of springtail observations, with nearly 15k as of this writing. - TI] 

Springtails are very tiny arthropods that are found basically anywhere where soil or similar conditions exist. They are hexapods but separate from insects, and they rarely grow more than 6mm in length. Most eat plant and fungal material, but some are predatory. In addition to being amazing looking, most have a furcula, or small appendage, folded under their abdomen which can be released so it hits against the substrate and propels the organism into the air - a good way to escape from predators. 

When identifying, Alexis will usually look up springtail observations in Europe, both at Needs ID and Research Grade levels. 

There are a good amount of local springtail species that are easy to ID/confirm, even with low quality photos - the problem is that there are just as many which are nearly impossible to get to species from photos. Along with the high portion of low quality smartphone photos and false positive AI IDs, this can make it quite a challenge to sift through springtail observations. Luckily I've accumulated a few good online resources and keys to help with identification, many of which are listed on collembola.org (a website that's great for finding comparison photos too).

Along with the more general searches like this, sometimes I will pick out a certain genus or species and do a deeper dive on the ID features, so that I can go through a big batch of observations of that group to try and fix any mis-IDs. 

He’ll also collaborate with other springtail identifiers, such as in this observation. He says,

I've learned so much from the incredibly supportive iNat community, and I love being able to give some of that back through helping others. I also just enjoy the process, and I continue to learn a lot while identifying, whether through interactions with other springtail identifiers or looking closer at a species I am unfamiliar with.

iNat was a big part of getting me more seriously into macro photography, and still plays an important role in my process for identifying and learning more about my subjects. Whenever I am traveling it's also interesting to look through observations in the area in advance, to see what I could find and what to look for.

How does one go about finding and photographing springtails? Alexis has some tips:

The easiest place to find a variety of springtails is in the leaf litter and on/dead wood on the forest floor. My usual method is just to look underneath dead wood in the forest, but there are springtail species adapted to just about any habitat (Including the high slopes of mount Everest and deep underground in caves). The main challenge is just spotting them, since most species are only a couple of millimeters in size or even smaller. Springtails are especially active (and come to the soil surface more) in moist conditions, so it's always worth taking a look after it has rained.

[For photography] get as close as you can. If you have a camera and dedicated macro lens that's great, but even just with a phone there are lots of great options for cheap clip on macro/microscope lenses that allow you to get great close up images! Many springtails need details of the pattern to get an ID, so getting a top down angle is usually most important. Try and get other angles as well if you can, especially if you are unfamiliar with the species. Some springtails also just can't be identified to species from photos at all, so don't worry if an observation only gets to family or genus (although this happens just as much from a lack of springtail identifiers).

I asked Alexis to name a favorite springtail of his and he chose the genus Sminthurides:

These are absolutely tiny and live at the edge of ponds and in swampy areas. They have a really fascinating courtship ritual, males have specialized antennae with which they clasp onto the antennae of the females. They “dance” around face to face like this on the water's surface, which is amazing to watch. I saw these for the first time last year and got one of my favorite springtail photos to date.

- check out Alexis discussing his photography award in this YouTube Video!

- @frankashwood’s giant springtail was an Observation of the Week back in 2023!

- if you're not an expert you can definitely help identify observations on iNaturalist by refining them!

Happy World Taxonomist Appreciation Day! In response to community feedback, we’re introducing a small update to vascular plant curation guidelines on iNaturalist. You can find it here. But in short, for vascular plant curators should now wait for community feedback before resolving "Relationship Unknown" taxa, and we're also considering referencing World Flora Online for Ferns.

Background

For many branches of the taxonomy, iNaturalist follows external references. Keeping iNaturalist in sync with these references is a very important task for volunteer curators. For example, for birds we follow the Clements Checklist which updates annually. Thanks to the incredible hard work of curators like @birdwhisperer crafting taxon changes, iNaturalist is able to stay in sync with Clements as it updates. iNat staff are incredibly grateful for this dedicated volunteer curation work.

For vascular plants, iNaturalist follows Kew’s Plants of the World Online (POWO) as our external reference. Under existing curator guidelines, taxon changes for "Relationship Unknown" taxa (i.e., taxa with no deviations) with fewer than 100 observations are typically made in the direction of the external reference without an embargo period or community review. For example, in the Heath Family that would include Arbutus xalapensis var. texana (30 obs) but not Andromeda polifolia glaucophylla (470 obs) here.

Many iNaturalist users have reached out to tell us that these curator guidelines do not give the community time to work with Kew to advocate for updates and fix errors on the POWO end.

New Experimental Policy

As a result, we’re introducing an experimental change: curators should now open a flag and wait one month before making taxon changes to Vascular Plant "Relationship Unknown" taxa. This allows time for community input before aligning with POWO.

• For taxa with existing flags, the month-long waiting period starts today and ends on April 19.
• If no feedback is received, or if there is community consensus that following POWO is advisable, curators may proceed with the taxon change after the waiting period.

For example, for Arbutus xalapensis var. texana based on research on POWO compose a flag like this:

How to Contribute to POWO Improvements

If you have expertise in vascular plants, please monitor flags for your taxa of interest and help improve POWO by:

• Providing input on flags
  • If you support the change, leave a comment confirming that following POWO is appropriate.
  • If you oppose the change, explain why and suggest alternative actions.
• Requesting updates to POWO
  • If a taxon needs correction, you can contact Kew by emailing bi@kew.org to request an update.
  • Since POWO only includes names registered in IPNI, you should submit names here: https://ipni.org/registration/.
  • Please keep the flag discussion updated with any correspondence with Kew.
• Creating a deviation when necessary
  • If Kew cannot update POWO in a timely manner, curators should create a taxon framework deviation to signal that iNaturalist is diverging from POWO.

Reviewing the Experiment

We’ll check in on this experiment in six months to assess:

• How many flags received no response.
• How many flags were uncontroversial and led to straightforward changes.
• How many flags were controversial, resulting in discussions, efforts to update POWO, or taxon deviations.
• POWO’s responsiveness to update requests.

Based on these findings, we will develop a long-term curation plan for vascular plants on iNaturalist.

Exploring changing the referencing for Ferns to World Flora Online

There has been long running debate within the community about whether POWO is a good reference for the 'fern' vascular plant classes Lycopodiopsida and Polypodiopsida. In consultation with @choess, @sbrobeson, and @joelnitta, we're exploring transitioning the reference for these two classes from POWO to World Flora Online. If we implement this change we'll announce it as an update to this post.

Thank you for all your help observing, identifying, and curating plants on iNaturalist. Vascular plants are our largest group by number of observations, so it makes sense that maintaining a well-curated taxonomy with broad community buy-in is challenging. We truly appreciate everyone's efforts toward this goal.

This April will mark the 10th anniversary of the City Nature Challenge, and iNaturalist is more involved than ever before!

What is the City Nature Challenge (CNC)?

If you use iNaturalist regularly, you've probably heard of the City Nature Challenge (CNC). Maybe you've even participated, or noticed the surge of observations at the end of April. But what exactly is behind this global event?

The CNC is a four-day bioblitz held every April. Cities around the world compete and collaborate to find species, make observations, and connect people with nature in urban areas. It started in 2016 as a friendly contest between San Francisco and Los Angeles. Since then, it has grown into an international event, with 690 cities and nearly 2,000 local organizers participating last year.

How is the City Nature Challenge organized?

The CNC was co-founded 10 years ago by Lila Higgins (@lhiggins), Rebecca Johnson (@rebeccafay), and Alison Young (@kestrel), leads of the Community Science teams at the Natural History Museum of Los Angeles County and the California Academy of Sciences. Today, these two museums serve as the Global Organizing Team, working with local organizers worldwide.

Each CNC city or metro area has one or more local organizers. These individuals come from diverse backgrounds, including students, educators, and environmental professionals. Local organizers are the heart of the CNC. They encourage their communities to explore and document nature using platforms like iNaturalist. Their efforts help expand the challenge and engage more people each year. The Global Organizing Team provides training, tools, and resources to help local organizers promote and implement the CNC in ways that fit their communities.

City organizers often build partnerships with schools, local governments, and community groups to spread the word. They also coordinate events like bioblitzes, nature walks, and moth lighting to engage participants.

CNC participants in Tuxtla Guitiérrez, Chiapas, Mexico. Photo by Adzuari Cruz Romero.

What role does iNaturalist play in the CNC?

iNaturalist has been the platform powering the City Nature Challenge since 2016 when it was just Los Angeles versus San Francisco, and continues to serve as the primary platform cities use to document nature during the event. This year, it's playing a bigger role than ever. With Alison Young (@kestrel) moving to a new position as the Director of Outreach Programs, iNaturalist is taking a more active role in the CNC in promoting the event and engaging the community. Expect more updates about the CNC as the event approaches!

Results of the City Nature Challenge over the past nine years.

How can I participate in the City Nature Challenge?

Mark your calendar for CNC 2025! Here are the key dates:

• April 25-28: Make observations
  
• April 29-May 4: Upload observations and help with identifications
  
• May 5: Results announced

With just seven weeks to go, now is the time to prepare. You have two ways to participate:

1. Take part in your city’s CNC event – Check this tentative list to see if your city is participating. If it is, you’re all set! Get ready to start making observations on April 25. Want to help promote the CNC in your city or hold an event? Projects are currently being added to the CNC 2025 umbrella project – once you see your city’s project, reach out to the project owners and let them know you'd like to help!
   
2. Join the Global Project – If your city isn’t on the list, you can still take part in the CNC 2025 Global Project. This option is available for anyone, anywhere in the world. The Global Project will count toward the overall numbers of the City Nature Challenge!

Helping with identifications is also a great way to contribute! While observers must make observations in participating cities or join the Global Project, anyone can help identify species worldwide. Taxon experts and dedicated iNaturalist users play a huge role in refining observations and guiding new participants. Every identification helps move observations closer to research-grade status and lets new users know their contributions matter.

We’re excited to bring the world together for biodiversity during the 10th City Nature Challenge!

Acknowledgement: Big thanks to the rest of the global organizing team: Amy Jaecker-Jones (@amyjaecker-jones) (NHM), Sam Tayag (@songdog-st) (NHM), and Olivia VanDamme (@olivia_v) (CAS) for continuing to devote part of their professional time to making the City Nature Challenge run.

Our Observation of the Week is this Ornate Cow Tick (Dermacentor reticulatus, Луговой клещ in Russian), seen in Belarus by @shapomacro!

Ticks! Most people (including myself, and I love arachnids) find them pretty creepy or gross, and obviously they can be very harmful as a disease vector, but as Andrey Shapolov’s eye and photography skills show, they can also be fascinatingly beautiful. “I just like them,” he tells me. “They look quite unusual and interesting. I like to photograph various parasites.”

A macro photographer from Belarus, Andrey became interested in insect and arachnid photography in 2015, and says “I fell in love with nature and its small inhabitants.” The tick photos you see in this post were taken with the Canon MP-E65mm f/2.8 lens, which can provide up to 5x magnification, and are focus stacks of 78 and 198 images, respectively. 

I photographed this tick back in October 2024. I often go out to shoot macro in our park outside our house. We have a small field behind the park where there are a lot of ticks. Since our summers have been quite dry and hot in recent years, the ticks hide. And they only appear in the spring and fall.

A member of the hardbacked ticks (family Ixodidae), the ornate cow tick is found in Europe and western Asia and like other ticks it feeds on the blood of its hosts. Unlike most other blood feeders, ticks can spend days feeding on their host animal and, as Sarah Zhang in The Atlantic writes, 

Ticks use saliva to manipulate the body of their hosts so their bites stay painless, itchless, and as unobtrusive as a bug swelling with blood can be. Scientists have since cataloged more than 3,500 proteins from the saliva of various tick species…

The exact cocktail of a tick’s saliva proteins changes every few hours, [tick researcher José] Ribeiro says. The thousands of proteins in its saliva are highly redundant in function, and the tick cycles through them as a way of circumventing a host’s immune system.

A member of iNaturalist since 2023, Alexey (above, with his macro set-up), tells me “I mainly use iNaturalist to identify the species I have photographed. It really helps me learn new things about insects and spiders.”

- one well known tick-borne disease is Lyme Disease, and some lizards like the Western Fence Lizard have a protein in their blood that actually kills the bacteria that cause Lyme Disease!

- if you’ve been bitten by a tick, here are insctructions for how to remove it.

A Major Milestone for Biodiversity Mapping

We passed a major milestone with today’s update to iNaturalist’s Computer Vision and Geomodel—100,000 modeled taxa!

To mark this achievement, we’re excited to make the Geomodel Expected Nearby Maps available in three key ways:

• As a new iNaturalist Open Range Map Dataset, now available for download.
• As new interactive, downloadable layers on taxon page maps, making species distributions more accessible.
• As part of the ArcGIS Living Atlas of the World announced today at the Esri Federal GIS Conference and available soon.

This dataset provides a powerful new tool for researchers, conservationists, and policymakers to better understand and protect biodiversity—a key part of iNaturalist's mission.

What Makes the iNaturalist Open Range Map Dataset Unique?

Understanding where species occur and how their distributions are changing is fundamental to biodiversity conservation. Yet, while satellites provide near-continuous imaging of the Earth, most species distribution datasets remain artisanal—often hand-drawn by experts or based on statistical correlations with indirect environmental variables like temperature rather than direct biodiversity observations.

The iNaturalist Open Range Map Dataset is different:

✅ Built on hundreds of millions of observations from the iNaturalist community.
✅ Improving each month as new observations are added.
✅ A true data-driven complement to traditional range maps, reflecting actual species occurrences.

Mapping Species Richness at Scale

One way to showcase this dataset is by estimating terrestrial vertebrate species richness. The map below was generated by stacking 12,000 individual range maps from the dataset, covering approximately 30% of all terrestrial vertebrate species (12k out of 39k). Areas with higher species richness are shown in red.

Despite known biases towards more 'charismatic' species in this subset of vertebrates, this estimate aligns with established biodiversity patterns, showing peak species richness in the tropics, similar to other global biodiversity assessments (e.g., this study).

Similarly, a map of small-ranged terrestrial vertebrates (species with range sizes smaller than the median for their group) highlights endemism hotspots in regions such as the Andes and Madagascar, corroborating findings from other biodiversity studies (e.g., this study).

A Long Road Ahead—But a Clear Path Forward

The maps above focus on terrestrial vertebrates where 30% of all species are in the model. However, the gaps are much larger for other groups. Across all described species, while iNaturalist has documented ~25%, we currently have enough observations to model only 5% of them.

However, where data exists, our models produce accurate, dynamically updated species distribution maps. This gives us hope: if we can continue growing the iNaturalist community and fill in species and geographic gaps, we can provide the conservation community with the high-quality, dynamically updated species distribution data it urgently needs.

Filling the Gaps—Together

To reach the next milestone—200,000 taxa modeled—we need to expand both taxonomically and geographically.

• Taxonomic Expansion: Observations of lesser-known species, such as insects, plants, and fungi, are critical for increasing coverage beyond well-documented terrestrial vertebrates.
• Geographic Expansion: The map below is a copy of the terrestrial vertebrate species richness map from above where H3-4 hexagons with fewer than 100 observations of modeled species are grayed out. These gaps represent missing data, but they also represent an opportunity.

By engaging more observers and identifiers worldwide, we can fill these gaps, refine our models, and build an open, data-driven map of life on Earth.

Join us in making this vision a reality! Click the map to zoom in. Can you help spread the word about iNaturalist to help fill these gaps?

We released v2.20 today which is our first model with over 100,000 taxa! It has 805 new taxa compared to last month's 99,545 taxa and is trained off data exported on January 19, 2025.

We're celebrating this 100k milestone by releasing the iNaturalist Open Range Map dataset.

The graph below shows model accuracy estimates using 1,000 random Research Grade observations in each group not seen during training time. The paired bars below compare average accuracy of model 2.19 with the new model 2.20. Each bar shows the accuracy from Computer Vision alone (dark green) and Computer Vision + Geo (green). Overall the average accuracy of 2.20 is 88.7% (statistically the same as 2.19 at 89.8% - as described here we probably expect ~2% variance all other things being equal among experiments).

Here are the new taxa since the last model:
Plants • Mammalia • Reptiles • Other Animals • Mollusks • Birds • Protists • Fishes • Fungi • Amphibians • Arachnids • Insects

Thank you to everyone in the community who contributed the observations and identifications for all of the newly added species!

Have you ever tried to identify a caterpillar and wished that the species suggestions didn’t just show you adult butterflies and moths? Now on the website you will see more relevant photos displayed in ID suggestions.

We’ve updated the Computer Vision Suggestions on the web to display Taxon Photos that are most visually similar to the observation photo. This improvement should make it easier to determine which suggestions are the best match—across all taxa! We're highlighting insects here but it works for plants and fungi, too!

What’s New?

Previously, the Computer Vision system displayed the same taxon photo for a species regardless of the observation. Now, it selects the most visually similar Taxon Photo for each suggestion.

• If you post a photo of a caterpillar, the suggestions will prioritize Taxon Photos of caterpillars.
• If you post a photo of an adult moth, the suggestions will prioritize Taxon Photos of adult moths.

Before this update, the system would show the same default photo whether the observation was a caterpillar or an adult moth.

How Does It Work?

The Computer Vision system now calculates visual similarity between the observation photo and the Taxon Photos for each suggestion.

For example, if you observe a White-lined Sphinx Moth caterpillar, the system will compare your image to Taxon Photos and display the most similar one—in this case, a caterpillar rather than an adult moth.

This improvement depends on having high-quality, diverse Taxon Photos that represent different life stages, sexes, and variations.

What Are Taxon Photos?

Taxon Photos are representative images displayed on each Taxon Page. Each taxon can have up to 12 taxon photos, and these are manually curated by the community to help with identification. You can add or edit Taxon Photos by clicking “Edit Photos” in the Curation menu on any Taxon Page.

• If you delete a Taxon Photo, the change will be reflected in suggestions immediately.
• If you add a new Taxon Photo, it may take up to 24 hours to appear in suggestions.

To improve the system, Taxon Photos should include clear, high-quality images that represent the diversity of the taxon (e.g., different life stages, sexes, etc.). Here are some taxon photo guidelines you should follow.

How This Improves Coarser Suggestions

This update also helps clarify why the Computer Vision system suggests a higher-level taxon (e.g., genus) when species within that group look very different.

For example:

• Suggestions of the beetle Genus Asphaera, which includes highly variable species, will now display a genus-level Taxon Photo that visually resembles the observation—instead of the default Taxon Photo which may look very different. This works because all Taxon Photos of species below the genus are being considered.

Change to Taxon Page Links

For species-level suggestions, clicking the “View” link will now open the Taxon Page with the most visually similar photo as the default. However, this feature does not apply to coarser (non-species) suggestions.

Next Steps

We’d love to hear your feedback on this improvement! We plan to roll out this feature to the iNaturalist mobile apps soon.

Let us know what you think and how this affects your experience with Computer Vision Suggestions.

Our Observation of the Week is this flowering Climacoptera lanata amaranth plant, seen in Kazakhstan by @bektemirosmonali!

“I have been interested in nature since childhood. At that time, of course, there were no mobile phones, so we spent most of our time outdoors, as our family was engaged in raising both small and large livestock,” recalls Bektemir Osmonali, Head of the Plant World Cadastre Laboratory "Institute of Botany and Phytointroduction" in Kazakhstan.

I spent most of my summer vacations far from the hustle and bustle of the city, in a place without electricity or other conveniences. For some, this might have felt like a punishment, but for me, it was the most enjoyable and exciting time.

In university he majored in scientific biology and at first couldn’t decide which field to focus on: microbiology, zoology, or botany. “However,” he says, “after my first practical work, I realized that plant research was my true passion.”

Since 2016 he’s delved deeply into plant systematics, earning his PhD, and his research has focused on the Chenopodiaceae family [on iNat, considered part of Amaranthaceae - Tony], as well as other lesser-known families and genera.

One member of the family is Climacoptera lanata, but Bektemir tells me

it is extremely rare to observe, let alone closely examine, the flowering of Climacoptera lanata and related species, as it occurs within a very short period and is usually not seen in large numbers. Nevertheless, I always try to find flowering specimens whenever possible.

Last year, during an expedition to the Mangystau region, I was fortunate to come across a flowering specimen of Climacoptera lanata among other fruiting individuals. Moreover, this particular plant was not only in bloom but also had a well-formed, aesthetically pleasing flower, which I managed to capture in a photograph. Of course, I took numerous pictures, but only a few of them turned out truly beautiful.

In most plants, petals are responsible for the main decorative appeal, but in this family, the stamens are often more visually striking. For example, Climacoptera lanata, which belongs to this family, has beautiful bubble-shaped pink stamens. However, this is not its only distinctive feature—during fruiting, it forms a winged, predominantly pinkish fruit that is also quite attractive, especially in fields where Climacoptera lanata is the dominant species.

Bektemir (above) credits his supervisor Polina Vasilievna Vesselova with encouraging his plant photography. 

Ever since she praised my plant photographs, I have been striving to improve my photography skills and select better angles for my shots…The species of [Chenopodiaceae] are relatively unknown and do not have prominent morphological traits that are immediately noticeable. The true beauty of these plants is revealed through macro photography, as their distinguishing features are incredibly small.

There are many reasons why I use iNaturalist. One of the main ones is the opportunity to publish my work openly, as well as to discuss species identification and their morphological features. iNaturalist has given me the chance to develop creatively and improve my photography skills.

(Photo of Bektemir by Polina Vasilievna Vesselova. Some quotes have been lightly edited for clarity.)

- you can check out Bektemir’s research here, and his YouTube channel here!

- our last Observation of the Week from Kazakhstan was the first known photos of a jumping spider species by @talgar-t64!

Our (belated) Observation of the Week is this Red-trumpet Calcareous Tubeworm (Serpula columbiana), seen in the United States by @jensseattle!

“I am obsessed with the diversity of marine life here in the Pacific Northwest, where I now live,” says Jen Strongin, who traces her love for marine biology back to her childhood on the Atlantic Ocean.

My family spent a couple of weeks every summer at the edge of Nantucket Sound in South Yarmouth, Massachusetts. I remember getting up early with my mom,  walking the beach and looking for horseshoe crabs and conchs. The beach was (and still is) endlessly fascinating to me with all of its weird and wonderful inhabitants.

A few weeks ago Jen visited a floating dock in Tacoma, Washington, and did her thing:

I was…lying on my belly, hanging over the edge of the dock, looking at all the animals who had decided to settle there. Floating docks are amazing places to observe marine life! There were several Serpula columbiana, looking gorgeous with their cirri all fluffed out. I still cannot get over how beautiful some of our marine worms are here in the Pacific Northwest. I love photographing them.

True to their common name, tubeworms live in a tube they create from calcareous secretions. Much of the worm’s body stays in the tube, but it can extend feathery radioles, or tentacles, which is what Jen has captured here. The radioles are used for both filter feeding and gas exchange. If disturbed, the worm will quickly draw them in and plug the hole to its tube with an operculum.

“I have been working with the Seattle Aquarium's Beach Naturalist Program for the past 8 years, helping to educate volunteers and the public about life on our local shorelines,” says Jen (above). She’s also a professional photographer who specializes on marine life and fungi.

iNat is such an amazing resource. I love being able to learn from others, share observations that may be helpful to scientists/researchers, and to be able to keep track of what I have observed.

- you can check Jen’s photography on her website!

- PBS has a nice video about related Christmas Tree Worms.

Our Observation of the Week is this Horn Stalkball fungus (Onygena equina), seen in Ireland by @paddythecurious!

I think most of us are used to seeing fungi growing on soil, or decomposing logs, but iNatter Paddy Kiely came across a fungus that specializes in a different substrate in southern Ireland, where he lives.

Onygena equina I have come across in two different areas around Tipperary. Both in hilly areas with a forest close by. For this observation, I was looking for wax caps in the field adjacent to the forest. In the forest there was many sheep carcasses and that's where I found the fungi.

Look closely and you’ll see no fungi on the sheep’s bone, just its horns, and that’s because horns are made of keratin (just like fur, claws, reptile scales, and the like), and Onygena equina grows on nothing else. It’s able to break down the keratin in horns and hooves, and then of course it will grow fruiting bodies from which it releases its spores. It’s reputed to sometimes infect human fingernails as well, although I personally haven’t been able to find a peer-reviewed paper showing that - if you know of one, please share in the comments!

Paddy (above, with a Boletus edulis mushroom) says he’s fascinated by “everything fungi.”

I fell down the rabbit hole 7 years ago and learn more and more every day. I have maybe ten books, my favorite, The Fungal Wheels of Europe edition 1 and 2. Also I use a microscope to check spores. I help moderate in 4 groups in Facebook and triage and identify for emergency identification for plants and mushrooms, which I was delighted to be asked to help out in a few months ago. I love to eat mushrooms and have eaten over 150 species in the south of Ireland. I love to find every type of mushroom. Basically I'd like to know about them all. Every day is a treasure hunt.

I use iNaturalist to log my findings of fungi, plants and animals. I believe this is very important for scientific data and research. Also, it's good to look back on for my own research.

(Some quotes have been lightly edited for clarity.)

- other fungi that grow on keratin may be more familiar to humans: ringworm and athlete’s foot. They’re all in the order Onygenales.

- just found out about this fungus yesterday, which grows on coniferous resin. Amazing.

- just a reminder that if you're interested in foraging, one shouldn't rely solely on iNat suggestions when determining the edibility of an organism. It's best to seek out local experts and learn from them.