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Since M4.5 - M9 dwarfs exhibit equatorial rotation velocities of order 10km/s on average, radial velocity surveys targeting this stellar population willlikely need to find methods to effectively remove starspot jitter. We presentthe first high resolution Doppler images of the M4.5 dwarf, GJ 791.2A, and theM9 dwarf, LP 944-20. The time series spectra of both objects reveal numerousline profile distortions over the rotation period of each star which weinterpret as starspots. The transient distortions are modelled withspot/photosphere contrast ratios that correspond to model atmospheretemperature differences of Tphot-Tspot = 200 and 300 K. GJ 791.2A is a fullyconvective star with vsini = 35.1 km/s. Although we find more starspotstructure at high latitudes, we reconstruct spots at a range of phases andlatitudes with a mean spot filling of ~3%. LP 944-20 is one of the brightestknown late-M dwarfs, with spectral type M9V and vsini = 30.8 km/s. Its spectraltime series exhibits two dominant transient line distortions that arereconstructed as high latitude spots, while a mean spot filling factor of only1.5% is found. The occurrence of low-contrast spots at predominantly highlatitudes, which we see in both targets here, is in general likely to beresponsible for the low amplitude photometric variability seen in late-Mdwarfs. For GJ 791.2A, the radial velocities induced by the starspot featuresyield an rms velocity variability of 138 m/s, which can be reduced by a factorof 1.9 using our reconstructed surface brightness distributions.

Starspot distributions on fully convective M dwarfs: implications for radial velocity planet searches