South American Mouse ID+update (3/29/13)

[Antonsrkn]

I know this is a looong shot but can anyone help me ID this mouse from Ecuador? Found in the Andes at just over 3000 m above sea level, any sort of info is appreciated.

[Chris Smith]

Approx. how big was it?

Hopefully Curtis will chime in!

-Chris

[Curtis Hart]

The only book I have on Ecuador is Mammals of the Neotropics Vol. 3 Ecuador, Peru, Bolivia, Brazil. There are no rodents in the plates that are a good match. I used Wikipedia to get a list of the mammals of Ecuador and eliminated things I knew it was not. It's tough as there are few images to work with. Habitat would be helpful to know. In the first 10 minutes of looking, genus Thomasomys looks like a possible match maybe paramorum? I'll look again when I have more time.

You might try posting this over at Mammalwatching.com


Curtis

[Antonsrkn]

Thanks guys!

Approx. how big was it?

I would say that the body was probably 3-4 inches.

Habitat would be helpful to know.

It was in an interandean valley at a little over 3000 m asl. The habitat it was in is a forested area inbetween the 2 sides of the valley with a stream running through the bottom of the valley, as you can see it was found alongside the stream. I don't know exactly how to describe the type of forest it was in, the trees weren't very tall (compared to lowland rainforest) but the vegetation was dense and it seemed fairly wet, in certain areas it was quite mossy.

genus Thomasomys looks like a possible match maybe paramorum? I'll look again when I have more time.

Fantastic! That's more than I knew and I really appreciate the help! It would be awesome if it turned out to be paramorum, i looked it up and its an endemic species to ecuador, that would be way more interesting than anything I expected.

Mammalwatching.com

I'll check it out.

Curtis and Chris, thanks again!

[Curtis Hart]

I'd like to highlight the words "possible" and "maybe" in my reply. Your rodent seems to have a distinctive face, so I think it is IDable, with an expert or better book.



Curtis

[Antonsrkn]

I'd like to highlight the words "possible" and "maybe" in my reply. Your rodent seems to have a distinctive face, so I think it is IDable, with an expert or better book.

I still appreciate the effort the possible/maybe are still a big step up from where I was at before. All I could say was that it was a mouse haha. This next part is a bit embarrassing but I misread your post and thought you said "with an expert or a better look" instead of better book So I went and dug up other shots I had of the mouse that I thought maybe showed its face a bit better or from a different angle. I didn't notice my mistake until I started posting the photos, but since I went through finding and uploading them here are a bunch more photos of it. I will try posting on mammalwatching sometime tomorrow or this weekend.

These shots aren't much good, I screwed up the settings while taking the photos but maybe there's something additional in them that might make an ID easier.








Badly out of focus but its a head on view, I dont know if any important ID characteristics are more visible this way...

Adios...

[gbin]

I think your finding it streamside is a big clue to its identity. I bet it's a South American water mouse (Neusticomys spp.).

Very cool!

Gerry

[Curtis Hart]

The drawing at the link below looks a lot like your rodent. That would be Neusticomys monticolus. It would be nice to find the original location the drawing came from for more info.


http://www.planet-mammiferes.org/drupal ... monticolus

[Antonsrkn]

Update! I emailed Jon at mammal watching.com and he got in contact with Fiona Reid, a mammalogist in Ecuador for me. This is what she says...

I looked through your pictures and I am pretty sure it is a Neusticomys, and
most likely N. monticolus. These rats are very rarely seen so it is great to
have pictures of a live one! The water rats all have short, blunt faces for
swimming and they have hairy hind feet as can be seen in your pics. They
usually have a bit of webbing between the hind toes which I don't see in
your pics. Small eyes are typical. I would expect to see more vibrissae and
slightly less ear pinnae, but that could be due to the animal in life vs.
death and other variables. Hind feet are very long (as in your pics) and fur
is dense. Most water rats have hairy tails, but I am not sure about
Neusticomys. It is said to have dense short hair on the tail....
....
Thomasomys would be a possibility but they have much longer faces and bigger
ears with naked-looking pinnae. So I would go for Neusticomys. A reference
is Diego Tirira's Mamiferos del Ecuador, 2007. It has some photos of these
rats. It is a nice field guide but all in Spanish.

If you could send me pictures that show the tail, hind feet, front feet or
face in focus - especially feet and tail pics, so I can zoom in, I would be
better able to be sure of ID. I can also ask Carlos Boada, a friend in
Ecuador who traps a lot in the mountains. He works on Thomasomys so I think
he could rule out (or not) that genus, which doesn't leave many options. He
has caught one Neusticomys up there I think.

So still not quite resolved but getting there. Really makes me wish I had gotten better photos.

[gbin]

Are you kidding, Anton? I think your pictures are very good - and it's rather surprising you got any pictures at all! Not many people have seen any of these South American water mice (I don't know why some folks call them water or fishing rats, as cute and small as they are) in situ, let alone managed to take a series of photographs of them there. I'm very envious of both your experience and your photographs from it.

Gerry

[dery]

Congrats on your great find Anton.

[Andy Avram]

Update! I emailed Jon at mammal watching.com and he got in contact with Fiona Reid, a mammalogist in Ecuador for me. This is what she says...
So still not quite resolved but getting there. Really makes me wish I had gotten better photos.

Fiona Reid, more than just a mammalogist in Ecuador, check out those books she authored on Amazon:
http://www.amazon.com/s/ref=nb_sb_noss_ ... fiona+reid

Including, the updated Peterson's Guide to Mammals of North America. I would say she is a pretty good reference!

I wish more people took the time to figure out the little rodents, and other small mammals they saw on trips (and locally).

[gbin]

I meant to say something about Fiona Reid being a significant mammalogist (especially for Latin America), too, Andy, but I forgot - I'm glad you chimed in to point that out. Anton, the fact that your query attracted her interest emphasizes just how cool your sighting and pictures are, in my opinion.

Gerry

[mrichardson]

I've found both Jon Hall and Fiona Reed very helpful in the past. Fiona is certainly the expert when it comes to obscure mammals! Great pics of the mouse BTW. Happy that you're a little bit nearer with the ID.

[Antonsrkn]

Thanks for the additional replies! It's definitely cool knowing i saw something out of the ordinary. And wow I hadn't realized exactly who Fiona Reid was, I'm impressed and grateful she even took the time to take a look at my photos.

[Rags]

No input on the ID, but interesting stuff.

[Antonsrkn]

The ID has changed once more!

Fiona Reid sent me another email:
Carlos Boada took a look at your pictures and says it is a Thomasomys. The tail is not hairy enough nor ears small enough for a Neusticomys in his opinion (I am sure he is right, he has trapped a lot in that area, and as I said I was a bit puzzled by those features)). The species would be either Thomasomys erro or Thomasomys ucucha.

T. erro range map:
http://maps.iucnredlist.org/map.html?id=136345

T. ucucha range map:
http://maps.iucnredlist.org/map.html?id=136487

The area I found it in was near Ibarra to the north and falls outside of either range, my guess is that it is T. erro just because its not as range restricted. It remains a really cool find for me as no matter which species it really is, its really range restricted and an ecuadorian endemic! I wasn't expecting anything near as interesting as this when I initially saw a small mouse, my only thought was atleast there's some snake food haha, but luckily I like to document all the wildlife I see as best as I can with photographs.

[gbin]

Awesome! Thanks for the update!

Gerry