[Taxacom] ID of this pet rodent species

[YEN Shen-Horn]

Dear Taxacomers

Sorry to bug you for the ID of this rodent (see the picture attached), which was brought to my lab by one of my students.
It is dormice-like and said to be native to South America, but I don't think it's related to dormice according to my very limited knowledge about mammals.

If anyone could help to give some directions I would be very appreciated.

best regards 
Yen

Dr. YEN Shen-Horn
Associate Professor
Department of Biological Sciences
National Sun Yat-Sen University
70, Lien-Hai Rd., Kaohsiung 804
TAIWAN
 
E-mail: shenhornyen at mail.nsysu.edu.tw 
Tel: +886 7 5252000 ext 3612
Fax: +886 7 5253609
URL: http://www2.nsysu.edu.tw/biology/En/shenhornyen_en.html