There is a new lens on the updated Pentax K-mount lens roadmap Ricoh released yesterday: the HD Pentax-D FA 70-200mm f/4 (the HD Pentax-D FA★ 85mm f/1.4 lens was already listed on the 2017 roadmap).
Update: the new HD Pentax-D FA 70-200mm f/4 lens will probably be based on the current Tokina AT-X 70-200mm f/4 PRO FX VCM-S.
Here is the new Pentax lenses launch order for 2018/2019:
1. HD Pentax-D FA★ 50mm f/1.4 SDM AW: Spring 2018
2. HD Pentax-DA★ 11-18mm f/2.8ED DC AW: Summer 2018
3. HD Pentax-D FA 70-200mm f/4: Spring 2019
4. HD Pentax-D FA★ 85mm f/1.4: 2019
The rest of the lenses on the roadmap (with a “2019 or later” tentative release date):
Via PentaxRumors