Mammalia

Mystery of the Mangy Squirrel Slurry – solved!

A few posts ago I presented a puzzle – what were the strange arthropod-like creatures I found in a KOH-dissolved slurry of eastern gray squirrel skin? I canvassed colleagues from around the world, and none had a definitive answer (though Terry Galloway from the University of Manitoba guessed the correct order, or suborder depending on your taxonomy). Yesterday I received a second square of skin from the same squirrel, also sent by Jamie Rothenburger. This time I didn’t dissolve it in KOH but rather just plopped it in ethanol and examined it underneath a dissecting scope. Lo! Dozens of the tiny mystery animals were attached to the squirrel’s hairs. Even better, four older instars, including an adult, were also present. So, what did they turn out to be? Sucking lice (Anoplura), most likely Enderleinellus longiceps Kellogg & Ferris based on papers by Kim (1996 a, b). UPDATE: no, it is not E. longiceps, it doesn’t even belong to that genus. I keyed out the adult female today and she turned out to be Neohaematopinus sciuri Jancke based on Kim et al. (1986). I was a bit too eager to get photos of the critters and didn’t wait until the slides were completely cured, so the images below are a little blurry. First are photos of embryonic lice still in eggs, then photos of what I think is a second nymphal instar. The scalloped structure beneath the tarsal claw that was particularly obvious on the legs of the animals in the original post are less striking in the nymph.

Nits on squirrel hair.

Two eggs on a squirrel hair, one occupied.

Enderleinellus in egg B

Close-up of one embryo popping out of the egg.

Enderleinellus nymph habitus B

Nymphal sucking louse, Neohaematopinus sciuri.

Enderleinellus nymph head

Internal mouthparts of the nymph.

Enderleinellus nymph claw with scallop

Tarsus of second leg showing faint scalloped structure.

Enderleinellus nymph scales

A nice scaly patch of integument from the dorsum of the nymph.

Neohaematopinus sciuri female habitus

Adult female Neohaematopinus sciuri.

Neohaematopinus sciuri sternum

Relative sizes of tarsal claws of legs I to III and shape of the sternal sclerite (arrow) helped to identify the female as belonging to the family Polyplacidae and the genus Neohaematopinus.

References

Kim, K.C. 1966. The species of Enderleinellus (Anoplura, Hoplopleuridae) parasitic on the Sciurini and Tamiasciurini. J. Parasitol. 52: 988-1024

Kim, K.C. 1966 The nymphal stages of three North American species of the genu Enderleinellus Fahrenholz (Anoplura: Hoplopleuridae). J. Med. Ent. 2: 327-330.

Kim, K.C., H.D. Pratt and C.J. Stojanovich. 1986. The Sucking Lice of North America: an Illustrated Manual for Identification. Pennsylvania State University Press, University Park.

Who likes shrews? These mites do!

My friend Allan Lindoe, fossil preparator extraordinaire, lives on an acreage near Athabasca and makes the journey south to Edmonton about once a week to carefully remove rocky matrix from around the skeletons of long-dead fishes, mosasaurs, and dinosaurs. Two cats share his home and frequently bring him presents of wild game. A few weeks ago I washed a mixed bag (literally) of a dozen shrews he had accumulated over the summer and fall of 2015. Chewed-on shrews are not easy to identify unless you know a lot about insectivore teeth, but based on tail length and known distributions of shrew species in Alberta, they were one or more of the masked shrew (Sorex cinereus), Arctic shrew (S. arcticus), pygmy shrew (S. hoyi) and/or dusky shrew (S. monticolus)*. Some of the shrews were rather decomposed, so I wasn’t expecting much from the washings, but I was pleasantly surprised: 6 species of mites! Members of both major lineages were present. From the Acariformes were Prostigmata (Myobiidae, Pygmephoridae and Trombiculidae) and Sarcoptiformes (Glycyphagidae). From the Parasitiformes there were larval hard ticks (Ixodida: Ixodidae) and what look like Melicharidae (Mesostigmata).  Myobiids, trombiculids, and ixodids are parasitic, and the others are all likely just phoretic. Who knew the zoo on shrews? Now you do.

Protomyobia female ex shrew

Protomyobia nr. claparedei female (note egg).

 

Protomyobia ex shrew

Protomyobia nr. claparedei male (note well-sclerotized aedeagus).

 

Protomyobia lv I think A

Larval Protomyobia nr. claparedei (note styletiform chelicerae).

 

pygmephorid ex shrew

Ventral view of one of the many pygmephorids from the shrew washings.

 

pygmephorid ex shrew legs I

Pygmephorid showing modified legs I.

 

chigger ex shrew A

Dorsal view of a shrew chigger (Trombiculidae).

 

chigger ex shrew B

Prodorsal shield of a shrew chigger, showing the posterior pair of trichobothria and single anterior median seta (just the base can be seen here) indicative of the family Trombiculidae, as opposed to members of the Leeuwenhoekiidae, which have two anterior median setae.

 

prob Oryctoxenus A

An Oryctoxenus sp. deutonymph (Glycyphagidae). Anterior is pointing up, and yes, it doesn’t have mouthparts.

 

prob Oryctoxenus B

Posterior hair-clasping structures of an Oryctoxenus deutonymph.

 

ixodid larva ex shrew A

A larval hard tick (Ixodidae).

 

ixodid larva ex shrew B

Retrorse spines on the tick’s hypostome help keep it attached to the host.

 

maybe Proctolaeleps A

Maybe a female Proctolaelaps sp.(Melicharidae). Not in great shape.

 

maybe Proctolaeleps B

The ‘procto’ part of Proctolaelaps refers to the large anal opening, or so the etymological legend goes.

*Smith, H.C. 1993. Alberta Mammals: an Atlas and Guide. The Provincial Museum of Alberta, Edmonton, Alberta.

 

 

Mystery of the Mangy-Squirrel Slurry

A few years ago I worked with members of the Vancouver Rat Project to investigate the cause of lumpy ears in rats from one of the shipping ports in that city. The rodents turned out to have ear mange caused by the sarcoptid mite Notoedris muris (Astigmata: Sarcopidae). As far as we could tell, this was the first record of N. muris in Canada. About two weeks ago, one of the co-authors of this paper, Jamie Rothenburger (now a Doctor of Veterinary Medicine doing her Ph.D. at the University of Guelph in Ontario), emailed to ask if I could look at a chunk of skin taken from a mangy squirrel. Jamie suspected Notoedres centrifera Jansen. This sarcoptid species has been reported to cause mange in many species of sciurids in North America and may be hindering recovery of the western gray squirrel.

image (1)

Diagnosis and drawings of Notoedres centrifera from Klompen (1992).

Jamie had only histological sections through mangy squirrel skin, though, which are difficult to match to species descriptions. I said sure and soon received a small frozen chunk of integument via courier. The skin sat in a saturated KOH solution for a couple of days to encourage its dissolution. The single mite I managed to find in the smelly skin slurry matched Klompen’s illustrations of N. centrifera (above), and was a similar size (200 um).

Notoedres prob centrifera Jansen ex squirrel skin ventral

Ventral view of the sarcoptid mite I found in the squirrel slurry.

Notoedres prob centrifera Jansen ex squirrel skin dorsal

Dorsal view of same.

So, diagnosis confirmed, end of story, right? Well, actually, the mite isn’t the reason for the ‘mystery’ in the title of this post. In addition to the one tiny Notoedres, I found several almost as miniscule (600 um), translucent cigar-shaped objects in the digested squirrel skin. Out of curiosity, I mounted three of them yesterday. [UPDATE: I revisited the slurry and found a fourth critter, images of which are at the bottom of the post]. Today I spent several hours futilely trying to pin them down to a taxon finer than ‘probably some sort of arthropod’. My first thought as I mounted them was follicle mites (Demodicidae) in cysts, but nope, not enough legs. There seem to be only two pairs! Plus they end in single large claws or clawlike tarsi, whereas follicle mites have two small claws per leg. Embryonic insects in eggshells? Still not enough legs, unless the first pair develop much more slowly than the last ones. Maybe…see third photo below. What insects might be on squirrels? The critters don’t look much like lice, because to my knowledge no lice have a big tuft of bum setae. And what are those weird flash-shaped setae at the head end? Are those round things spiracles? And why is there scalloped ornamentation on the bases of the four well-developed legs? None of the many entomology texts I consulted had images at all similar to these.

ex squirrel mystery embryo ventral

Ventral view of one of the four-legged embryos (?) from the squirrel skin. Note the long whippy bum setae (I assume that’s the bum end).

ex squirrel mystery embryo lateral

Lateral view of one of the other embryos.

ex squirrel mystery first legs maybe

It looks like there might be another pair of very poorly sclerotized anterior legs, with the faint leg tips clasping on of the more posterior legs.

ex squirrel mystery flask setae

Flask shaped setae on the head-ish end.

ex squirrel mystery ant spiracle maybe

Something that might be an anterior spiracle.

 

ex squirrel mystery post spiracles maybe

A row of abdominal spiracles?

ex squirrel mystery leg fans

There’s a fan-shaped structure at the base of each of the sclerotized legs (most clear on second leg from the right). They remind me of the ventromental plates of chironomid larvae.

ex squirrel trachea and split fan

I managed to mount one of the mystery critters with legs spread out and saw that the fan is actually split, like an open bivalve shell. Note also the trachea.

ex squirrel weird round things

At the anterior end of the thing are two sets of what look like trichobothrial bases, but there are no trichobothria or other setae coming out of them on any of the four critters that I mounted.

 

I am thoroughly stumped. Help!

Reference:

Klompen J.S.H. 1992. Phylogenetic Relationships in the Mite Family Sarcoptidae (Acari: Astigmata). Museum of Zoology. Ph.D. thesis, The University of Michigan, Ann Arbor, MI, USA.

Cheese, soldiers, mites and mice

I’m reading “On Food and Cooking: the Science and Lore of the Kitchen“, a most absorbing book by Harold McGee. A while ago I finished the section on cheese. Among other fascinating tidbits, I learned that the crunchy crystals one sometimes encounters when eating cheese consist of calcium phosphate, calcium lactate, or the amino acid tyrosine. The Greek root ‘tyros’ means ‘cheese’, which suggests that tyrosine may first have been isolated from cheese (a hypothesis supported by Wikipedia). It also made me think of Tyrophagus putrescentiae (= rotting cheese-eater), a widely distributed mite pest of stored products and arthropod cultures that can rapidly go from a few individuals to a pulsing hairy carpet of thousands.

Tyrophagus on superworm container 27 Dec 2011 banner

A small subset of the hordes of Tyrophagus putrescentiae that overflowed from my tenebrionid culture.

A related ‘tyro’ mite is Tyrolichus casei, which is employed to make the unusual cheese Milbenkäse. But I also knew that ‘tyro’ referred to a raw novice, particularly a young soldier.  Did the ancient Greeks feed their new recruits on cheese? Off to the OED in search of an answer.  To my surprise, ‘tyro’ wasn’t defined under the common spelling, but rather under ‘tiro’, Latin for young soldier.  No mention of cheese, but also no etymology provided. Off to Google in search of a more complete answer. No agreement that I could find, but plenty of contention.

Even more recently, including yesterday, I employed cheese to capture some of the numerous mice (Mus musculus) that occupy the house, despite the presence of my cat Fred.  Or maybe because of my cat; I’ve seen mice march boldly up to to the catfood bowl and steal kibble from it as Fred watched complacently. Snap traps baited with Swiss cheese do a much better job of mouse control. As an acarologist interested in symbiotic mites, I of course have washed some of the mouse bodies. From the washings I picked out a few tiny fur mites.  They have impressively powerful claws on their first legs.

maybe Radfordia ensifera from HPs house mouse

One of the fur mites from my mouse washings.

My first assumption was that they were Myobia murismusculi (Prostigmata: Myobiidae). But this site says that M. murismusculi (a.k.a. M. muris) has only one claw on its second pair of legs. This individual clearly has two claws, which would make it a Radfordia. The claws seem to be equal in length, leading me to conclude that it is R. ensifera (illustrated here; unequal claws mean R. affinis). All three species are known from Mus musculus. It would be interesting to map the distribution and diversity of fur mites on house mice in Alberta, as one would predict that in longer-settled areas (e.g., old parts of Edmonton), the mice would have a greater number of mite species than in areas recently colonized by a potentially small number of founders.

Diamond Life

In mid-June I spent a week working a at a location farther north than I had ever been – Lac de Gras, 220 km south of the Arctic Circle in the Northwest Territories. On an island in Lac de Gras is Diavik Diamond Mine. Diavik employs about 1000 people to mine and process diamonds and to support the mining operations. The cafeteria is stupendous but the sleeping quarters are not particularly salubrious. It is a dangerous place due to gigantic vehicles, rockfalls, extreme weather and large mammals including caribou and grizzly bears. At Diavik, people are very very safety-conscious.

bad things can happen Diavik trip 12 June 2014 C

Diavik cautionary tale – me beside two heavy equipment tires and the pickup truck they crushed (photo by C. Uherek)

They have made some rather large holes in this island.

Diavik mining pits as seen from helicopter 17 June 2014

Diavik mining pits as seen from helicopter.

To compensate, in part, for their impact on the local environment, Diavik is supporting a number of research and remediation projects on and near the mine, including studies on soil and plants, and on stream fauna. I am involved in the latter via my M.Sc. student Christiane Uherek, whom I cosupervise with Bill Tonn, a fish ecologist in my department. Bill and a half dozen of his students have worked hard over the past several years to create and monitor an artificial stream connecting a previously isolated lake on an island near the mine site with Lac de Gras. The hope is that grayling and other fishes will use this stream to access the lake for breeding.  Christiane isn’t working on the fish directly, but rather on the artificial stream’s physical and biological characteristics. She will compare these features with those of nearby natural streams (references) to determine whether flow, woody debris and invertebrate assemblages of the artificial one fall within the range of variation of natural ones. It’s the macroinvertebrates that connect me to this project.

Reference 6 lake 16 June 2014 sml

Reference 6 Lake, from which Ref 6 Stream 1 flows.

To measure retention of organic matter we tossed artificial sticks and paper ‘leaves’ into streams and measured how far they went downstream before they got stuck.

HP dropping artificial sticks into stream with Chrisitane recording13 June 2014

Me dropping artificial sticks into an artificial stream, with Christiane recording data.

Terrestrial vertebrates (in addition to humans) are surprisingly common at Lac de Gras. Voles, ground squirrels and willow ptarmigan regularly dropped by to check out what we were doing.

male willow ptarmigan West Island stream 15 June 2014 C sml

Male willow ptarmigan wondering why we are measuring sticks.

According to the New Shorter Oxford, ‘ptarmigan’ is a falsely Greekified modification of the original Gaelic name ‘tarmachan’, which means ‘grumbling or croaking’; apt if you listen to the bird’s rather frog-like calls.

During my week there I came to understand why Diavik emphasizes safety with such religious fervour. We experienced lightning storms, rockfall alerts, a vehicle that burst into flames in front of our truck, and a couple of grizzly bears, one of which we escorted with the help of a helicopter from the mine site, across frozen Lac de Gras, to the mainland.

chasing grizzly bear across Lac de Gras with a helicopter 16 June 2014 A

Note to self: grizzly bears can run very fast for a very long time. Fear them.

 

 

 

 

 

Etymological deer-stalking

Odocoileus virginianus skull from Chamela field station collection Feb 2014

Skull of a white-tailed deer from UNAM Chamela collection.

Earlier this year my friend John Acorn was frustrated by the genus name for white-tailed and mule deer: Odocoileus.  Greek and Latin dictionaries didn’t help to make sense of it, no matter how potential roots were parsed. He enlisted me and Selina Stewart, a professor of classics at the University of Alberta, in the hunt for the origin of this name.  It was an exciting few hours of Googling!  Many emails were exchanged as we followed blind leads, downloaded uninformative pdfs, and speculated wildly. Then, by chance, I thought to look up where the description of the type species of Odocoileus was published, with the hope that the author of the genus had actually explained his rationale for choosing the name. To my surprise, neither O. virginianus nor O. hemionus – the only two extant members of the genus – turned out to be the type species.  Instead, it was a deer I’d never heard of: Odocoileus speleus.  A cave-dwelling deer? What could this mean? The author was C.S. Rafinesque, and the description was published in The Atlantic Journal, and Friend of Knowledge, Vol. 1, in 1832.

Rafinesque lived from 1783-1840 and had quite a diverse career, dabbling in zoology, botany, geology and Mesoamerican linguistics. He named many species of plants and animals in addition to cervids. Wikipedia calls Rafinesque a polymath, but he didn’t excel in all endeavours. For one thing, his stint as the botanist at Transylvania University in Kentucky ended badly after he had an affair with the wife of the university’s president. For another, he was quite careless with his spelling. This explains Odocoileus. The genus is based on a fossil (or possibly subfossil) tooth found in a cave – hence speleus. Rafinesque had intended the generic name of the tooth’s owner, which he thought might be a type of pig, to refer to the tooth’s hollowness (see excerpt below).  But rather than Odontocoelus, which would have matched his intent well, he wrote the jumbled name that still stands today. There were two attempts at the beginning of the 1900’s to emend the spelling to something more etymologically, but these were deemed unjustified.

Odocoileus speleus description

That spelling was a persistent challenge for Rafinesque is evidenced by his naming a population of  white-tailed deer Corvus macrourus.