DISCUSSION AND CONCLUSIONS
The nature of the Pakistani lagomorph record is surprising. Why is there only a single isolated ochotonid tooth at ca. 18 Ma, and an apparent lack of lagomorphs, from either family, between 18 and 7.4 Ma? Is the absence of Lagomorpha between 18 and 7.4 Ma real? We believe it is, as there are good samples of small mammals throughout the Siwaliks from the upper levels of the Kamlial Formation through the Dhok Pathan Formation (Flynn et al. 1998). However, the pattern of occurrence of lagomorphs at the base of the Siwalik sequence and the top of the Dhok Pathan Formation and younger units suggests that taphonomic factors were at play at those times. At these Siwalik levels, lagomorphs are uncommon. The presence of only a single lagomorph tooth at the base of the Kamlial Formation may reflect a predator bias in the early Miocene. The appearance of leporids, and more specifically, of leporines, only in the late Miocene is not unexpected, as this is the earliest appearance of this group elsewhere in the world, e.g., in North America (but earlier in the late Miocene), Europe, Asia, and Africa (Patnaik 2002;
Voorhies and Timperley 1997). Given the large number of fossil small mammals known from northern Pakistan, the paucity of leporines thereafter (latest Miocene and younger) is indeed surprising because leporines are often a common element in modern assemblages. As with the earlier records of lagomorphs, these more recent records may also record a predator bias: i.e., predators that captured few larger lagomorphs compared to other smaller prey items. From elsewhere on the Indian Subcontinent, lagomorphs are (poorly) known from only Pliocene and younger deposits (Forsyth Major 1899;
2002). Further collecting in northern Pakistan is not expected to yield abundant additional specimens, but perhaps more diagnostic remains may be collected, especially from the younger units. This would add tremendously to our knowledge of the southern Asian record of this important group.