Simplify the following text for a Grade 12 native English-speaking person.
Original: The gladiators initially were described from old museum specimens that originally were found in Namibia ( Mantophasma zephyrum ) and Tanzania ( M. subsolanum ) , and from a 45-million-year-old specimen of Baltic amber ( Raptophasma kerneggeri ) .
Simplified: The mantophasmids were originally described from old museum specimens that found in Namibia ( Mantophasma zephyrum ) and Tanzania ( M. subsolanum ) , and from a 45-million-year-old specimen of Baltic amber ( Raptophasma kerneggeri ) .