We have studied the angular dependent de Haas-van Alphen oscillations of LaRu$_2$P$_2$ using magnetic torque in pulsed magnetic fields up to 60T. The observed oscillation frequencies are in excellent agreement with the geometry of the calculated Ferm
i surface. The temperature dependence of the oscillation amplitudes reveals effective masses m*($alpha$)=0.71 and m*($beta$)=0.99 m$_e$, which are enhanced over the calculated band mass by $lambda^{cyc}$ of 0.8. We find a similar enhancement $lambda^{gamma} approx 1$ in comparing the measured electronic specific heat ($gamma = 11.5$ mJ/mol K$^2$) with the total DOS from band structure calculations. Remarkably, very similar mass enhancements have been reported in other pnictides LaFe$_2$P$_2$, LaFePO ($T_c approx 4K$), and LaRuPO, independent of whether they are superconducting or not. This is contrary to the common perceptions that the normal state quasi-particle renormalizations reflect the strength of the superconducting paring mechanism and leads to new questions about pairing in isostructural and isoelectronic Ru- and Fe-pnictide superconductors.
