Slitherine

The Empires unit system is simpler than that of FOG2, likewise the range of national archetypes. As far as possible the Empires units map to historically accurate FOG2 units, but because there are less different units in Empires we have mapped them to the historically more common unit types.

The units you mentioned above are ones that were already obsolescent by 310 BC, so they did not make the cut when simplifying the FOG2 unit range to match the available number of different Empires units.

As has been mentioned elsewhere, FOG Empires was designed by AGEOD as a full game in its own right, and not as an add-on for FOG2. During the development process, the publisher Slitherine raised the possibility of making the games work together as an optional extra. This proved to be practicable, and AGEOD and Byzantine Games have worked together to make it a reality. Understandably, however, AGEOD did not want to compromise their core game design to accommodate an optional extra, so there will inevitably be differences between the national and unit organisation of the two games that require compromises in the transfer to FOG2.

Thanks for answers

yes I understand
These are 2 different games and us have to accept the differences

But in 310 BCE the peltast skirmisher were already obsolete?
me I knew the peltasts only as a tirailleurs operated by throwing javelins at short range