Out of the box: A can of lice, good lice, naked middle thirds, and the hideous truth

Phthiracarus borealis (Trägårdh, 1910) = Louse + Mite + of the North

I’ve recently been looking at a bunch of ‘bug blogs’ and trying to assess them so I could make a statement about the health of bugbloggery for an upcoming symposium. One of the things that has struck me so far is that, although at the start the spirit may have been willing, the current blog is often weak. Many of the once interesting bug blogs that I have found seem to have run out of steam. If they haven’t posted in more than a year, I’ve been calling them ‘moribund’, but then I realised that here I haven’t posted since July. A quarter moribund? Well, I often feel even worse then that, so I guess I can’t complain if I am being quarter-hoisted by my own petard.

Mesotritia nuda (Berlese, 1887) = Middle + third + naked

So, here’s a mini-post, mostly just to keep from sliding into moribunditry, but also to try and work out one of those arcane problems that keeps me up at night – devising common names for obscure mites that no one has ever seen. In terms of existential angst, this must surely rank among the more absurd, but it is part of my job. I could just shoot from the hip, but I take even the more absurd aspects of my job seriously. I’ve blogged about this problem in other posts, but it hasn’t gone away, so here’s a current example: Box Mites. Being a ‘box mite’ is more a grade of evolution than a taxon – the ability to pull the legs into the body and shut the box has obvious advantages when a predator is trying to grab you by the leg and has evolved several times. The mechanism has been studied in some fascinating papers (e.g. Sanders & Norton 2004), but the authors have wisely never gone beyond the generic ‘box mite’. Unfortunately, Box Mites have done very well over the eons they have been around and acarologists have been giving them lots of obscure Greek and Latin derivative names for almost as long.

Atropacarus striculus (CL Koch, 1835)  - I hesitate to say what this may mean

Unfortunately, my scheme to use the Latin binomials as the source of my ‘common names’ has acquired an itch: the most diverse group of box mites belong to two superfamilies with names from the Greek for ‘lice’ (phthir) and ‘mite’ (acar), the Phthiracaroidea and Euphthiracaroidea, or ‘Louse Mites’ and ‘Good Louse Mites’.  There are mites that live like lice in the hairs and feathers of their hosts, but these aren’t them. The juveniles of box mites burrow in decaying plant material and the adults wander around the soil looking for each other and more decaying leaves and needles into which to lay their eggs. I don’t know what Perty was thinking in 1841 when he erected the genus Phthiracarus, but perhaps he was feeling itchy. Well, lousy name or not, even these mites have also been subjected to interesting studies of the box-making mechanism (e.g. Schmelzle et al. 2010) without wandering past the ‘box mite’ meme. So, I think I will draw my line in the sand at ‘box mite’ and try to summon forth names from the genus or species with which to adorn the box. So far, though, I must say I’m not having much luck. Take Atropacarus striculus as an example. I can’t find any root for ‘striculus’, but perhaps it refers to a stricture. I suppose the area where the legs are withdrawn may look strictured. Unfortunately, all box mites have a similar ‘stricture’. The generic name is also obscure. Perhaps from the Latin for hideous, terrible or cruel (atro-), but then why the extra ‘p’ before acarus? It’s times like these that I’m just glad I can still afford decent Australian wine. I think it is time I sought some inspiration there.

Faculifer sp. – a mite that infests the feathers of Australian doves

How small are mites: the Full Stop Test

8 Oribatid mites scaled to a 12 pt Times Roman period (0.5 mm dia.)

Recently The BugGeek posed an interesting challenge: “Can you talk to 10-year-olds about science?” I found this especially interesting because, as an acarologist, I find it difficult to explain the study of non-pest mites to people of any age or educational level. Usually when asked my occupation, I just say ‘I’m a scientist’ or, if among university types, ‘a biologist’ or ‘I work on bugs’. Other than with voluble taxi drivers, this usually proves satisfactory. Sometimes (usually under the influence of alcohol) I do try to explain to strangers the excitement I feel about the diversity of intricate morphologies and amazing behaviours exhibited by mites. But in my experience, if you have a party that has been going on for too long, then I am just the person you need to send even the most couch-bound inebriate scratchingly on their way.

A few years ago, though, I was asked to try and explain mites to 2nd Graders. I decided that the critical information was size – if I could explain how small mites were to an 8 year old, then I’d have a chance. I played around with a how many mites would your foot-print cover (a number too large even for a government deficit) and a penny, but even a penny can hold about 7000 of the smallest mite in the picture above and even in a large poster the mites are too small to see. I finally settle on a Times Roman 12 pt period, conveniently 0.5 mm in diameter. Times Roman and similar serif fonts are those most commonly used in publications (the little feet make a sort of dotted line for the eye to follow while reading) and every sentence ends in a full stop. What could go wrong?

Well, the good news is the 2nd Graders liked the pictures of the mites. The bad news is that ‘period’ does not compute in the 8-year-old mind. We tried inverting the background so that the period was black and the background white (which involved several hours of cleaning up black speckles), but ‘what’s a period?’ proved too great a hurdle. Oh well, it still makes a nice poster.

 

On Mites, Roofs & Jargon: Tectoribates

A Roofed Roamer from aspen litter under the January snow

The search for the origin of Oribatida has made some significant progress thanks to a number of classicists and oribatologists and after I’ve tracked down one last reference, all will be revealed. In the meanwhile, in a comment on the last post, James Trager pointed out that “ a better translation for Tectoribates would be either thatch roamer or roof roamer (roofs having once been mostly made of thatch)”.  This hypothesis is supported by the OED, which gives the origin of words like ‘tectiform’ (=roof-shaped) from the Latin ‘tectum’ (=roof). Additional support comes from Gordon Gordh’s and David Headrick’s excellent A Dictionary of Entomology (ADE, 2001 CABI), who point out that ‘tectiform’ is used to describe insects like cicadas that hold their wings roof-like in repose and also from Donald Borror’s handy Dictionary of Word Roots and Combining Forms (1971, Mayfield Publishing Company) that gives ‘tect-’ as arising from the Latin and Greek for roof. This raises a number of problems though. First, my Tectoribates species are neither arboreal (so not roof mites) nor from grasslands (so thatch would be misleading), nor is any structural feature like thatch or a sloping roof. Second, acarologists have their own definition:  tectum (pl. tecta) – any shelf-like projection of the cuticle.

Acarologists often go their own way on terminology, and this is especially true of oribatologists. As a recently reconverted oribatologist (after a quarter century pursuing other types of mites), my pet peeve with the oribatid jargon is ‘sensillus (pl. sensilli)’ – used for the motion-detecting seta that emerges from a cup-like receptacle on the prodorsum (the spiky, club-like structures on the image above). All the rest of animal morphology uses the neuter form ‘sensillum (pl. sensilla)’ for a sensory seta or other sense organ. ‘Sensillus’ causes no end of confusion and snide comments when a literate, but non-oribatological, referee gets a paper. However, in defence of this non-conformity, it is worth noting that ADE gives ‘sensillum’ as being derived from the Latin ‘sensus’ (=sense), a masculine noun, and so the oribatologists may hold the high ground here.

On further study, this also seems true of ‘tectum’, or at least there is more too it than an A-shaped roof. Cassel’s Latin Dictionary (1968, Wiley) gives ‘tectum’ as the substantive of ‘tego’ the verb ‘to cover’ and exemplars of usage including burying, protection by a shield, and to conceal. The last two would seem to go to the heart of the tecta of oribatid mites: most such structures are designed to shield or cover the legs or other parts of the body where a nasty predator might try to gain a foothold. In the picture above you can see a variety of such tecta including the wing-like pteromorphs that cover the legs, the pedotecta at the base of the legs, the tutoria* (from the Latin to guard or protect) protecting the outer sides of legs I , and the median lamellae (from the Latin for a small plate) covering the tops of legs I. Nature must be very red in others’ teeth and claws for an oribatid mite.

Looking down on lamellae roofing the prodorsum

In Tectoribates the lamellae are unusually well developed and I suspect that Antonio Berlese may have been thinking ‘roof-like’ when he coined the genus in 1910. So, I’m going with Roofed Roamers and my thanks to James.

*tutorium, tutoria (not tutor as the spellchecker would have it)

Going batty: What’s in a name?

Pterochthonius angelus: Literally 'Wing Earth Angel'

Last year I got what I thought was a strange request. The people on my project who have to deal with the public were finding it difficult to explain why they needed to sample soil mites on people’s land. They suggested that people might be more responsive if I would give the mites names. I replied that I had already given them names – the Latin binomials – and if they would ‘Speak the speech, I pray you, as I pronounc’d it to you’, they had all the names they needed. But no, it seems that scientific names come trippingly not, on the tongue, and make most landowners uncomfortable or downright suspicious. Of course part of that may be that I tend towards my own idiosyncratic pronunciations. I may confuse scientists whose first language is not English (e.g. Pinus always sounds like a pine-us from me), but they still seemed good enough for media and landowners. But no, they asked for common names, please, just like birds and plants and if I didn’t do it, they would coin their own.

Synchthonius crenulatus - Fused-soil crenulate?

Well, I’m not one to make another’s job harder than it has to be, but unfortunately although there are common names for a few mites – mostly pests of one sort or the other – soil mites mostly go about their business with no one the wiser. So what to do? Well, since I work in a bureaucracy, first up was a protocol. Rule One was that, all else being equal, the common name should be based on the scientific name. Rule Two, that inequality being rife, the name should be reasonably descriptive of the morphology, ecology, or behaviour of the mite. Hence our Pterochthonius angelus at the top became ‘Angel-winged Soil Mite’. I thought that was pretty good – and probably pretty much what Antonio Berlese was thinking when he made it the type species of his new genus in 1913 (before that it was in Cosmochthonius – so God knows what he was thinking then). But I quickly hit a snag as with the clunking and obscure Synchthonius van der Hammen, 1952. This probably refers to a fusion of some of the lateral platelets, but I’m just guessing here. Still, maybe ‘Crenulate Soil Mite’ will do. But then came the first real impasse.

Camisia biverrucata - Nightgown two-warted

Behold Camisia biverrucata (CL Koch, 1839) – The Double-warted Nightgown Mite! Now that was fun and descriptive. When von Heyden proposed Camisia in 1826 my guess (I think I’ve become psychic) is that he was thinking the thick waxy coating of cerotegument was rather like a nightgown covering the mite.  Camisia is Latin and old French for a shirt or nightgown from which Middle English derived ‘chemise’ (and later Romance languages gave us the shorter camisole), so von Heyden certainly may have been daydreaming of nighties. The two ‘warts’ on the bum are diagnostic. Everyone at the Museum had a good laugh at this one and then I sent it on. My colleagues in public relations, however, were not amused. They appealed to me: ‘imagine trying to explain a “warts and nightgown mite” to a landowner’! Bugger, just when this exercise in popular nomenclature was getting more fun than frustrating! Hence Rule Three: no names too icky, too easily misconstrued, or potentially rude. So, we now have the ‘Twin Butte Nightgown Mite’ (its centre of abundance is around the town of Twin Butte).

Oribatula - Mountain-roamer-little

Well I lost that battle, but not the war: there are at least 7 other species of Camissia in Alberta. Unfortunately, they tend to have names meaning ‘spiny’, ‘double-thorned’, and ‘horrid’. I’d better start thinking of descriptive euphemisms. But there are other problems to coming up with common names and the Oribatula above is a good example. The Suborder Oribatida has a lot of generic names with similar roots, from Oribata Latreille, 1806, an obsolete genus. For example, species of Oribatula, Zygoribatula, Tectoribates, and Oribatella are common and diverse in Alberta.

Oribatella jacoti Behan-Pelletier, 2011 - Jacot's Little Roamer

No one is sure where the ‘oribat’ in Oribatida comes from, but one hypothesis is that it is from the Greek ‘oro’ referring to a mountain (as in ‘orogeny’) and ‘bat’ for ‘one who walks or haunts’. So, oribatid mites are ‘mountain roamers’? Well I guess it is possible. One could also translate ‘ori bata’ as the Latin for ‘mouth approval’, but that seems too weird even for an acarologist. ‘Bat’ can also mean a bramble in Greek and these mites do have a lot of spines, and ‘oro’ is Italian for gold, so maybe ‘thorny gold’ was the inspiration? I like that, but only because I just made it up out of the ether.

Propelops alaskensis - Alaskan Darkeye

So, with ‘Oribata’ unresolved, I’ve had to punt and went for ‘Roamer’: the probably undescribed species of Oribatula above is now officially the ‘Field Roamer’ – common in fields, croplands, and open grassy areas. Zygoribatula are ‘Yoked-Roamers’, Oribatella ‘Little Roamers’ and Tectoribates ‘Shelf Roamers’, but is there a better solution? Google tells me that there is a lizard in New Guinea named  Emoia oribata Brown, 1953, and an Australian spider named  Tegenaria oribata  Simon 1916, and even music called Ori Bata (the Ori beat?). Maybe ‘Oribata’ does mean something logical? Perhaps someone out there in the ether can help and offer me a better translation?

The Macromite Before Christmas

Water-skating Homocaligus adorned with Roynortonella pustules

The winter solstice (adorned with a full lunar eclipse on an almost clear night here in Edmonton) is several days past and my brief Albertan ‘mid-winter’ holiday season has just commenced. In Australia the first month of summer is almost over – Australia begins its summer on the first day of December, presumably out of the usual nonconformity or some other reason that was never clearly explained to me – but their summer solstice is just past and it is also the holiday season (with snow in the mountains, but otherwise warmer than here). Celebrating the longest night of the year makes a certain sense. Although I still have 4-5 months before green returns to the landscape, I can optimistically assume that the sun will be shining longer and longer each day, even if it is on clouds that are dumping snow on me, and eventually the winter will end, at least officially. So, in the spirit of my holiday season, I wish my readers, wherever they are and whatever their holiday or not, a happy Christmas and productive, healthy, and intellectually stimulating New Year.

An undescribed, but checklist making, Annerossella from Queensland

Over the last few years I have gotten into the habit of tarting up one of my mites for a Christmas card. This year I picked an unidentified Albertan species of Homocaligus – one of the two genera of the raphignathoid family Homocaligidae. This mite is a festive bright red in life and skates over the shallow margins of lakes among emergent vegetation and aquatic mosses. Eggs are probably laid on vegetation as in Annerossella knorri Gonzalez, a homocaligid described from the leaves of water lettuce (Pistia stratiotes) near Bangkok, Thailand. I suspect it is a predator, perhaps of the springtails (Podura aquatica) that hop along in this habitat. I once kept an undescribed Australian species of Annerossella in a small aquarium, but other than watching it skate across the water, I was unable to add anything to the knowledge of its ecology (at about 0.5 mm in length, it is difficult to observe). However, I did make one of my early coloured SEMs of the mite and posted it on the Mite Image Gallery at the University of Queensland. Much to my surprise this was the first record of the family in Australia and my friend Bruce Halliday, putting aside his doubts about the validity of ephemeral web publications, cited the image in his Mites of Australia, a checklist and bibliography (1998, CSIRO Publications). Interestingly, the image at the top of a species of Homocaligus is probably the first record of the family from Alberta.

A pustule from the gymnodamaeid Joshuella agrosticula at 40,000x

Although festive enough for the holiday in itself, I thought the Homocaligus needed more adornment. The pine cone-like bulbs on the mite are cerotegumental pustules from another mysterious Albertan mite, Roynortonella gildersleeveae (Hammer, 1952). This mite used to reside in the genus Nortonella Paschoal, named after the great oribatologist Roy A. Norton. Unfortunately, in 1908 a certain Rohwer had already used Nortonella for a genus of tenthridinid sawflies; thus, the name was preoccupied. I suggested the new name as a replacement that was in keeping with the author’s original intentions. Like other members of its family (Gymnodamaeidae), the surface of the adult mite has scattered fields of strange and intriguing Bucky Ball-like pustules. The pustules arise as the cerotegument dries after the adult moult in what must be some interaction between microfibers and wax. Their elaborate form and species-to-species variants keep me, if not tied to a particular belief in the nature of the Universe, at least still amazed by how rewarding the study of even the smallest parts of Nature can be.

For more on Homocaligidae and Gymnodamaeidae see:

Fan Q-H. 1997. The Homocaligidae from China, with description of two new species (Acari: Raphignathoidea). Entomol. Sin. 4: 337-342.

Gonzalez RH. 1978. a new species of mite on water lettuce in Thailand (Acari: Homocaligidae). International Journal of Acarology 4:221-225.

Walter DE. 2009. Genera of Gymnodamaeidae (Acari: Oribatida: Plateremaeoidea) of Canada, with notes on some nomenclatorial problems. Zootaxa 2206: 23–44.

Wood TG. 1969. The Homocaligidae a new family of mites (Acari: Raphignathoidea), including a description of a new species from Malaya and the British Solomon Islands. Acarologia (Paris): 11: 711-729.

Weekly Bits & Pieces: Oribatulid Leg-well Ornaments

A Dystopian Future Earth or on what a Zygoribatula rests its leg?

Although my postings have been infrequent, I think I’ve more or less reached my original goal of filling the mitey void left by the demise of the late UQ Mite Image Gallery with a set of false-coloured mite SEMs of equal or better quality and exceeded the original gallery in terms of scientific content (not to mention navel-gazing). Some day I will figure our how to use WordPress properly and have all of the images easily available for perusal without having to backtrack through all the omphaloskepsis, but until then I think I need to pay attention to Kaitlin’s point and try to post more frequently.

Since full-mite coloured SEMs take an extraordinary amount of time to compose, and I am flat-out fulfilling all of my other commitments, I’ve decided to start posting a few interesting bits & pieces of mites. I’m not sure that I even need to or should spend any time trying to tart these up with colour, because I find them extremely interesting just as they are. Well, I will let you all judge for yourselves:

Cerotegument in leg I well of Zygoribatula sp. 2

These images were grabbed at 18,000 magnifications and represent ‘ornamentation’ of what is called the cerotegument: a secretion alleged to be composed of waxes and proteins that coats the outer cuticle of oribatid mites. I thought that this ornamentation might be a useful taxonomic character in a messy genus, Zygoribatula, but other genera (Oribatula, Dometorina) in the family (Oribatulidae) have similar ornamentation.

Oh well, it is still interesting, but what is its function? The rest of the surface of these mites is covered with a more or less smooth and thin coating of cerotegument – presumably keeping water in the mite and other things out . But why these pedestals in the grooves where legs I are retracted when the mites are annoyed? (NB – much of the surface structure of oribatid mites can be explained as protection from predators grabbing hold of limbs.)

When I first saw this pattern, it reminded me of pictures in magazines of the pulp era showing cities of the future with interconnecting anti-gravity roadways: better yet, cities on some hive-planet of insectoid aliens (I prefer to think of our future in a more low density, back to nature, gardens in the sky kind of way). However, I am open to more realistic suggestions. I assume the flattened tops (maximum diameter about one half of a millionth of a millimeter) support the withdrawn leg and form an air chamber under the leg, but why?

And the answer is: Austromesocypris

Looks like peteryeeles from ptygmatics takes honours for this 2nd Electron Raster Challenge, or at least I agree with the first half of his rather broad hypothesis: Austromesocypris. Also, Koen Martens took a break during his most recent field trip to Australia to view the image and agrees (but points out dissection would be needed to determine the species). If you want to learn more about these fascinating terrestrial ostracods, then I highly recommend the 2004 paper by Martens and his colleagues, a wonderful combination of taxonomy, phylogenetic analysis, and zoogeography:

Koen Martens, Patrick De Deckker, Giampaolo Rossetti. 2004. On a new terrestrial genus and species of Scottiinae (Crustacea, Ostracoda) from Australia, with a discussion on the phylogeny and the zoogeography of the subfamily. Zoologischer Anzeiger 243: 21–36.

As for the blobs that have everyone stumped, you will have to take my word for it – rotifers – or at least that is what a few that I slided from a companion Austromesocypris turned out to be. The preparation for SEM was not very kind to them, but I thought they would make a nice link to the first Challenge and its spiny-headed rotifer gone monster. During the rainy season the forest floor is as wet as my garden in this torrential Alberta summer, which is extremely wet, so the rotifers may be commensals taking advantage of a mobile feeding platform. However, since this ostracod crawled out of a sample drying on a Berlese funnel, perhaps rotifers also engage in phoresy.

I know I have a few more Greyscale images of Austromesocypris somewhere on a cd, but since I can’t find them, I’ll just have to end this post with a tiny mite first described by the great A.D. Michael 125 years ago:

A mite found wandering the Meanook Biological Research Station in Alberta

Full Stop on Canada Day

Synchthonius crenulatus (Jacot) on a Times-Roman 12 pt Period

Samples have been pouring in to work for the last month, so the time, and more importantly, the extra energy for blogging have been in short supply.  Sorry to any readers who need new posts on a more regular basis, but today I offer you Synchthonius crenulatus (Jacot).

Presenting a mite in a way that makes sense from the perspective of a viewer is always difficult.  Most people do not grasp just how small mites are and this is especially true for children.  Supposedly, those of us with average eyesight can resolve down to about 0.1 mm.  So, in theory, you could actually see many of the mites around you as tiny flecks.  But once one has gotten past the stage of watching ants and eating dirt, why would you?  Mites are only really interesting when you can see them up close and personal.

The best way to make a mite personal would be to associate it with a familiar object.  A friend suggested the obverse of a Canadian penny might set off the golden coppery colours of this mite and the Maple Leaf would be a good image for Canada Day.  Unfortunately, if scaled to their true relative sizes, this mite would essentially disappear.   According to my quick back-of-the-envelope calculations, you could squeeze about 9,467 of these mites on to a Canadian penny (19 mm diameter), give or take a few thousand legs.

I know I could do this in Photoshop, but I just don’t have the energy (see above) and I would have to do it on my own nickle, so to speak, because if my employers asked me to do it, I would quit.  So, what would be an object of appropriate size?

I chose a Times Roman 12 point font period in the assumption that everyone who can read would be familiar with full stops (as we call the period in Australia).  I know from too much experience with marking student essays that commas, semicolons, and colons are on their way to extinction (or strictly random insertion), but most students still come up with a full stop every sentence or four.  As well as often seen, the 12 pt period has a nice 0.5 mm diameter (5x what the average eye can resolve).

Times Roman or another similar serif font should be familiar to most readers because the little feet on the letters help the eye move along a row of print, increase comprehension, and (with the exception of people with macular degeneration and some other eye problems) reduce eye strain during reading.  As a result, almost everything printed (at least by a competent printer) is in a Roman serif font.  [NB - on the computer screen and on the web, serif fonts are not so easy on the eye and san serif fonts along the lines of Ariel or Helvitica are more commonly used.]

Alas, tests with 2^nd Graders are tending to falsify my hypothesis that even children can relate to a period.  Good news is that they really like the pictures of mites; bad news is that they don’t seem to understand the perspective of the period.  Ah well, why be pessimistic?  Perhaps an understanding will grow with them and mites will have done their small bit to save the period from extinction.

A Simple Example of Complexity

A Eupheredermous Oribatid Nymph

Blogging has been light because the sun has returned to Edmonton and all my extra energy has been going into the garden.  In celebration of the late, but better than never Spring, I offer you one of my earliest and simplest exemplars, an arboreal member of the family Cepheidae from a rainforest tree in Queensland.  This was taken as a single grab on a predigital camera and later the negative was scanned in, masked, and colourized.

The reason that a single picture was adequate, is that the top of this mite is relatively flat and with a large spot size and long working distance, one picture caught most of the detail.  The detail, however, is relatively complex.  Many oribatid mites exhibit a developmental behaviour called eupheredermy (eu-phere-dermy = good-carry-skin).  Each time they moult their cuticle, a more or less circular patch of cuticle (the scalp) remains attached to their back (the notogaster).  As they continue to moult (oribatid mites shed their skin 3 times before becoming adults: larva to protonymph, protonymph to deutonymph, deutonymph to tritonymph), the scalps accumulate in a pagoda like fashion.   I can see at least three layers of scalps, so this mite was nearing the end of its development when it donated its all to Science (and possibly to Art).  Some mites continue this pattern into the adult, but in this family, the Cepheidae, the scalps are shed at the adult moult and replaced by a thick and typically highly ornamented cerotegument.

Cerotegument litterally means ‘wax cover’ and is an example of more or less logical jargon.  Noto-gaster, or back-belly, seems oxymoronic to me, but reminds me of an old song about a Zombie Jamboree.  Perhaps whoever coined this term was in a festive mood? Of all the jargn in this posting, however, I like ‘scalp’ the best.  It is simple and a bit bloody minded.

A mite that glitters

A minute tongue-twisting brachychthoniid mite

Just how small can a terrestrial arthropod get and still function?  I’ve read a few theoretical discussions on how large an arthropod can get, but not on how small.  This golden wonder is towards the small end of the mite size spectrum, at least for adult mites.  The bar at the bottom is a tenth of a millimetre and this adult is not much longer.  An even smaller egg, larva, protonymph, deutonymph, and tritonymph preceded it, however.  The record for the shortest known adult mite is about 0.08 mm (80 microns) and belongs to an eriophyoid mite – tiny worm-like mites that form galls, rust, and silvering on plants.

In life, this mite was a transluscent golden colour.  I couldn’t quite capture that vivid living hue, but settled for the idea of what it might look like if an Inca goldsmith was trying to capture the essensce.  Other brachychthoniids (a real tongue-twister and often misspelled – Greek: brachy for short, chthon for soil) are a bright orange as adults (e.g.Eobrachychthonius latior) and violet as immatures.