Arabic

šīm- - rat (BK 2 1300, TA 32 487)

Cf. also šayham- ‘porcupine’ (BK 1 1283, LA XII 328)

PS
*ŝVm- - kind of mouse, rat (SED II No. 214)
Not very reliable since ŠU in the Eblaite form points to ṯ rather than *ŝ or *š in the protoform which is not compatible with š in Arb.