  We report on the discovery of new Martian Trojans within the Minor Planet
Center list of asteroids. Their orbital evolution over 10^8 yr shows
characteristic signatures of dynamical longevity (Scholl et al, 2005) while
their average orbits resemble that of the largest known Martian Trojan, 5261
Eureka. The group forms a cluster within the region where the most stable
Trojans should reside. Based on a combinatorial analysis and a comparison with
the Jovian Trojan population, we argue that both this feature and the apparent
paucity of km-sized Martian Trojans (Trilling et al, 2006) as compared to
expectations from earlier work (Tabachnik and Evans, 1999) is not due to
observational bias but instead a natural end result of the collisional
comminution (Jutzi et al, 2010) or, alternatively, the rotational fission
(Pravec et al, 2010) of a progenitor L5 Trojan of Mars. Under the collisional
scenario in particular, the new Martian Trojans are dynamically young, in
agreement with our age estimate of this "cluster" of < 2 Gyr based on the
earlier work of Scholl et al. This work highlights the Trojan regions of the
Terrestrial planets as natural laboratories to study processes important for
small body evolution in the solar system and provides the first direct evidence
for an orbital cluster of asteroids close to the Earth.
