Mysterious organisms that keep you up at night

Since I started using iNat, not only have I learned more about organisms that I’ve personally encountered, but I’ve discovered all sorts of things through research that I had no idea existed. Fortunately or unfortunately though, we don’t know everything about nature yet. Sometimes I come across something that sticks in my mind, organisms that just make me wonder.

The first thing I remember making me feel this way was Facetotecta, a group of crustaceans that have never been seen as adults. That one still keeps me up at night sometimes. Why can’t we find them in a fully grown form, where are they hiding? Why have all attempts to make them grow in captivity failed? Have we seen them as adults and assumed it was a different species or something and just failed to connect the dots?

That’s far from the only example though. Biswamoyopterus laoensis is only known from a small handful of specimens; do they still exist in the wild somewhere? Where are they and why haven’t we found any yet? They’re probably endangered at the very least but can we help them somehow? I hope it’s not too late. And don’t even get me started on timber wolves, what even are they? Their own species, some kind of wolf/coyote hybrid, a subspecies of some sort… So many possibilities!

Anyway, I’ll stop rambling now, but what species tend to leave you with a lot of questions?


Maybe all the deep ocean tracks? There’re many kinds of mysterious holes on ocean floor, they can be from something we know or from something completely new, or sometimes they look like fossil tracks we find.
All the island parrots that were drawn but never seen again, some could be mutants or wrongly painted, it’d be nice to know factually which species were real.


I was recently shown a fern called Vittaria appalachiana and am a bit obsessed with it since - I actually discovered it in several other locations by now. For some reason this fern stopped producing sporophytes. All there is is the tiny 1mm or so big gametophyte which grows in dark rock crevices. It spreads with gemmae which can get splashed around by rain drops and then grow into a new gametophyte - which is an exact clone of the original one.

It just leaves me with so many questions… are they all exact clones, or are there several “strains” from way back in time when they must still have reproduced sexually? How can they be so widely distributed (the entire Appalachians and surrounding areas) without having spores? What’s the evolutionary advantage of reverting to this primitive existence when they have all the DNA to grow an advanced fern plant? Does (or did) the sporophyte actually exist, maybe as a tropical fern, and nobody realized it’s the same species? Is this a unique occurrence, or are there other plant species who reverted entirely to cloning for reproduction?


Biswamoyopterus laoensis there are skins of at least 3 different specimen. I do biodiversity conservation work in SE Asia and it’s not at all uncommon for species in this region (as well as tropical South America and tropical Africa) to be represented by only a single, a handful, or no specimen. There are a lot of species here, many of them already rare before the present-day era of ever more massive human impact, and there is often little research done on the biodiversity of specific areas. This is not through a lack of desire, it’s just that funding is scarce and massively competitive.

Often local people know about these species though.

With Facetotecta, we probably have seen the adult forms and just not recognized them as such due to a large morphological change between the larval and adult stages. This sort of issue is not uncommon, even in vertebrates; it’s a big issue in extinct species and is the source of ongoing debate on dinosaur species, with argument over whether certain fossils represent a unique species, or if they are juveniles of other known species.

That’s not to brush aside questions and mysteries, there are many things that we don’t know and should be constantly be questioning, it’s just to provide a bit of context.


I can’t think of a single species that keeps me up at night as much as our own–and most of the time, for the wrong reasons.

As for the rest of the lifeforms, I can’t think of any that doesn’t fill me with wonder and questions, at least at some level.

Only the hubris of humanity could have confidently created the term “simple lifeform”. Every lifeform influences every other lifeform. And we are constantly reminded of the complexity of this truth everytime we probe deeper into even the most mundane and previously well-studied species.

My current personal challenge is trying to get a grip on the self-mutating powers of red bread mold, Neurospora crassa, where a couple of years ago it was discovered to be able to self-mutate its DNA (especially transposons) to ward off viral transposable components.

It’s the kind of thing that can fill you with wonder just by lifting the compost bin lid.


The Untouchable Bathysphere fish are probably misidentified real species and I hate to bring something so cryptid-adjacent into this discussion but they’re odd.

Also, canine transmissible venereal tumors. What was the original host like?


I was just going to bring that up. The thread where they were discussed said that they are, in effect, the original individual dog who first developed one. Yet there was, presumably, a normal-seeming dog body which eventually died. The nearest similarity I can think of is plant clones grown from cuttings or tissue culture for which the founding seed-grown plant has since died.


I’ve know people who have said that knowing about undescribed species keeps them awake. Especially when you’re the only one in the foreseeable future who has the knowledge, resources, and time to put formal names on threatened organisms.


You might be interested in this thread I started a while back:
It discusses those “lost” species that may or may not still be out there somewhere. It’s pretty incredible how many there are.

They keep me awake too, but I unfortunately know I do not have the knowledge and resources to describe them.

I always knew there were undescribed species, but somehow thought they were “somewhere else” like the rainforest or the middle of Australia. Then I got interested in galls, and now I see a half dozen undescribed species every time I walk outside. Which makes me wonder how many other groups of organisms around me are also filled with undescribed species, and I just don’t know enough about them to tell.

As for more fun mysteries, my favorite has to be the reproduction cycle of eels. We’re finally beginning to understand it, which is really cool, but it’s been a mystery for thousands of years:

There is actually a theory that the mystery of the eel gonads is partially to blame for Sigmund Freud’s weird sex phobias.

Claus had the intention to prove that eels produce sexually, and set out to do this by locating a male eel. The year 1876 would find the young Freud assisting with this mission at Claus’ zoological research station in Trieste, a seaport city in northeastern Italy. Claus gave young Freud a rather monotonous task. For four weeks in what felt like an exercise in futility, Freud dissected hundreds of eels to try to locate testes. “All the eels I have cut open are of the tenderer sex,” he would report until around eel number 400 when finally, he found the prize: gonads, buried in the abdominal cavity. (source)

And then:

The only real surprise is how diffident Freud was about his discovery. Later in life, he avoided mentioning it – even going so far as to excise his report from lists of his publications. He may have done so simply out of disgust for the dissections he had performed. But another, more intriguing, explanation – hinted at by his friend, Ernest Jones – is that his frustration at being unable to find an eel’s testes may have triggered one of the sexual anxieties that were later to be so central to his psychoanalytical theories. If so, eels and their elusive gonads have a lot to answer for. (source)


The coolest thing I can think of is the still undescribed caterpillar of the one foot wide White Witch moth. I think there was social media post of someone claiming to have found the caterpillar, but I don’t believe it’s been reared to confirm. It must be a HUGE caterpillar.

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Those extinct animals right on the edge of description by naturalists are always interesting. Some species like Steller’s Seacows and Dodos we were able to describe and see alive, but too bad thing like moas or elephant birds went extinct right before the age of exploration and there are only a few vague descriptions of native peoples interacting with them. I always wondered how close some post-Ice Age megafauna got to “modern” human civilization (the last 6000 years).

There are so many subfossil bones of interesting creatures and you wonder what they looked like. They have only bones of some of the large Mascarine parrots but there are vague references to “large green parrots” from visitors in 1500’s. To be able to go back and experience the natural world way back then and imagine what species still existed on islands that humans had not reached yet.


A good example of this is the whalefish family, where the juvenile form, male, and female were described as three separate families until quite recently. Now looking back it seems obvious because accounts of each family noted peculiarities (whalefishs were only known from females, bighead fish had huge nasal organs and were only males, and mirapinnids never had specimens with developed sex organs). Luckily genetics allowed scientists to figure this out so maybe this will help with these parasitic crustaceans too.


Whoops, I guess I misread, thank you for correcting me! :)

Wow, that must have been quite the discovery! That reminds me of the story of the supposed “blue walleye”, which from my understanding was supposedly its own species for a while before eventually being dubbed a subspecies of yellow walleye. Later on though it was discovered that they were genetically the same as yellow walleyes and it was just a weird color morph.

I can’t believe I haven’t heard about this yet! We seriously haven’t found one? Yep, this gonna be one that drives me crazy for a while…I wonder where they’re hiding. Also I just found out there’s a group of people trying to find an adult female with eggs so they can rear them to see the larvae and they have a project here. As a moth nerd and someone who hordes projects, I’m about to smash that join button like a spotted lanternfly!


Question: If the adult has been formally described does the larval stage also needs formal description?

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No, it’s not necessary but it is certainly useful for completeness. The vast majority of moths are described only as adults. I don’t think there is a Lepidoptera species described only based on a larvae, but I guess that’s because if you have a larvae in your possession you will just wait until it pupates and emerges to see what the undescribed adult looks like.


and then the other way round would work too, if only the adult is known then potential larvae can be raised to confirm the identity of the larvae themselves based on the adult form.

Or more likely, you discover an undescribed species of parasitoid.


This paper answers a number of your questions.

Obligate asexuality is also present in a number of angiosperms, including many weedy dandelions.

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On a more personal note: I took a blurry cell phone photo of what appears to be Lepidocyrtus fimicolus because I didn’t feel like getting out my macro cam. L. fimicolus has no verifiable iNat/Bugguide records for California (though it is known to occur there).

I regret not taking out my macro cam.

To be fair, world records are a dime a dozen in the land of Uncharismatic Microfauna/flora (still thinking about the ceiseman “name an undescribed species if you patreon me” thingy), but still.