  We present the highest spatial resolution ALMA observations to date of the
Class I protostar GY 91 in the $\rho$ Ophiuchus L1688 molecular cloud complex.
Our 870 $\mu$m and 3 mm dust continuum maps show that the GY 91 disk has a
radius of $\sim$80 AU, and an inclination of $\sim$40$^{\circ}$, but most
interestingly that the disk has three dark lanes located at 10 AU, 40 AU, and
70 AU. We model these features assuming they are gaps in the disk surface
density profile and find that their widths are 7 AU, 30 AU, and 10 AU. These
gaps bear a striking resemblance to the gaps seen in the HL Tau disk,
suggesting that there may be Saturn-mass planets hiding in the disk. To
constrain the relative ages of GY 91 and HL Tau, we also model the disk and
envelope of HL Tau and find that they are of similar ages, although GY 91 may
be younger. Although snow lines and magnetic dead zones can also produce dark
lanes, if planets are indeed carving these gaps then Saturn-mass planets must
form within the first $\sim$0.5 Myr of the lifetime of protoplanetary disks.
