Passage: Other spectral classes include the T-, D-, and V-types (4 Vesta). The Ld-type is a new class and has more extreme spectral features than the L-type asteroid. The new class of O-type asteroids has since only been assigned to the asteroid 3628 Božněmcová.A significant number of small asteroids were found to fall in the Q, R, and V types, which were represented by only a single body in the Tholen scheme. In the Bus and Binzel SMASS scheme only a single type was assigned to any particular asteroid.

Question: What distinguishes the  Ld- type asteroid  from the L-type asteroid?
Ld-type is a new class and has more extreme spectral features