Corresponds to narrow eumelanosomes aligned in the same direction.

对应于沿同一方向排列的窄真黑素体。

By studying evidence of their eumelanosomes.

通过研究他们的真黑素体的证据。

We know that in modern birds, long and narrow eumelanosomes correspond to black and gray.

我们知道，在现代鸟类中，细长的真黑素体对应着黑色和灰色。

While short and wide eumelanosomes correspond to brown and reddish brown.

而短而宽的真黑素体对应于棕色和红棕色。