Deers has been used that way.

From A Popular History of Mammalia, 1850:

The subgenus Muntjacus is distinguished from the other deers by the horns being supported on elongated pedicels ...

From Comparative Genomics, 2000:

In contrast to other deers. the muntjaks display chromosome numbers ranging from the lowest chromosome number known in mammals of 2n=6 (female) and 2n=7 (male Indian muntjak; Muntiacus muntjak vaginalis. Figure 8) to 2n = 46 (Chinese muntjak; Muntiacus reeversi).

I would say that either deers or deer would be acceptable for this type of usage. However, if you want to be indisputably correct, you could use species of deer.

Deers has been used that way.

From A Popular History of Mammalia, 1850:

The subgenus Muntjacus is distinguished from the other deers by the horns being supported on elongated pedicels ...

From Comparative Genomics, 2000:

In contrast to other deers, the muntjaks display chromosome numbers ranging from the lowest chromosome number known in mammals of 2n=6 (female) and 2n=7 (male Indian muntjak; Muntiacus muntjak vaginalis. Figure 8) to 2n = 46 (Chinese muntjak; Muntiacus reeversi).

I would say that either deers or deer would be acceptable for this type of usage. However, if you want to be indisputably correct, you could use species of deer. I also suspect this is the most common term for this meaning, as neither deer nor deers sounds quite correct to me here.

Deers has been used that way.

From A Popular History of Mammalia, 1850:

The subgenus Muntjacus is distinguished from the other deers by the horns being supported on elongated pedicels ...

I would say that either deers or deer would be acceptable for this type of usage. However, if you want to be indisputably correct, you could use species of deer.

Deers has been used that way.

From A Popular History of Mammalia, 1850:

The subgenus Muntjacus is distinguished from the other deers by the horns being supported on elongated pedicels ...

From Comparative Genomics, 2000:

In contrast to other deers. the muntjaks display chromosome numbers ranging from the lowest chromosome number known in mammals of 2n=6 (female) and 2n=7 (male Indian muntjak; Muntiacus muntjak vaginalis. Figure 8) to 2n = 46 (Chinese muntjak; Muntiacus reeversi).

I would say that either deers or deer would be acceptable for this type of usage. However, if you want to be indisputably correct, you could use species of deer.