Mystery Acari (and the joys of metatranscriptomics)

As many of you know, I am working on a project involving desert rodents, and have come across a Acari (ticks and mites) species that I would love to identify. Please help!

The animals is specific to a single rodent species, Chaetodipus spinatus, which is found in the Southern California deserts.  I find 5-10 of these guys on the tail of every individual rodent of this species– they are always there, and never on any other rodent species. I have worked with these rodents for several years, now, so I am pretty sure of this mutually exclusive relationship. Neat!

In addition to the photos, I have a large amt. of sequence data, which consists of hundred million 150bp PE Illumina reads– mRNA. In this there is a 9kb chunk of mtDNA, which seems to have only ~80% sequence similarity to anything. There is some sequence data from Ixodes, including Ixodes pacificus (I thought it was gonna be this species), though nothing seems to match there..

There is a bunch of 16S sequence that seems to be Rickettsial, and there is some 18S and 28S that looks like is came from the Mesostigmata.. These things have 99% sequence similarity.. look good.

Anyway, this has been an interesting (difficult) dataset to work with, with ‘contamination’ from the vertebrate host, and now all this bacterial stuff… Plus the fact that I don’t really know what the parasite is.

Anyway, If you know what this animal is, please let me know!



  • Jessica Light

    My dissertation work was on heteromyid rodents and their ectoparasites; I think I may have worked with a spinatus or two, but I’ll have to go back to my records. I don’t recall ever seeing any ectos associated with the tail; that’s pretty cool! I was primarily looking for lice, but I did save all ectos from every heteromyid assessed. If you’re interested in what I have, let me know!

  • macmanes

    Hi Jessica. I was talking to Jim Patton the the other day about this. He has not seen ectoparasites on the hundreds of pocket mice he’s caught.. This is super surprising, as they are so common in Riverside County CA, or at least in Deep Canyon.