teuthos (masculine gender with definite article ho), a calamary or squid of a larger kind than teuthis (feminine gender with a definite article he)
However, zoological nomenclature has adopted teuthis as the standard name for squid or similar cephalopods regardless of size (Architeuthis, the giant squid, for example).
Ancient Greek used the feminine -is (-idos) ending in various names for animals, usually smaller in size.
alopekis mongrel between fox and dog
Titan (masculine), Titanis (feminine)
ÂZoological nomenclature has also used -is from Greek, but the gender in actual usage is not always feminine. There are -is endings from Latin as well, but they can be masculine or feminine.