I once did
a post on why I use Bos primigenius for the species of aurochs and cattle
although it is predated by Bos taurus. Opinion 2027 of the ICZN allows this,
and it has the advantage that Bos primigenius has a holotype, the incomplete Haßleben skeleton,
while Bos taurus neither has a holotype nor a lectotype. However, I am not
completely satisfied with that solution, because the fact that it is up to the
author’s preference can create a lot of confusion. Apart from that, Bos taurus
is the first name under which the aurochs was taxonomically classified (Linnaeus
mentions it explicitly as “ferus Urus” in his description), so it should not
end up on the taxonomical graveyard and it is questionable if opinion 2027 actually
applied because the aurochs was included in the description. But how to clear
up the mess and create a clear situation on what name to use for the species?
I see two
options:
- The ICZN publishes
a regulation for handling wildtypes and domesticates as different species. In
this case, domestic cattle would be Bos taurus and Bos indicus, and the aurochs
Bos primigenius.
- Someone
does a proper redescription of Bos taurus, with a lectotype that is a “ferus Urus”,
an aurochs and a few paratypes to account for the variability within the
species, wild and domestic.
The upper option
would not be useful. A universal species definition does not exist, and good
arguments can both be made for the stance that domesticates are the same
species as their wildtype and for the stance that they are different species.
But the case of cattle shows that the latter is not practicable. Since taurine
and indicine cattle descended from different variants of aurochs, they cannot
form one species together that excludes the aurochs. In this case, all three
(aurochs, taurine and indicine cattle) would have to be classified as separate
species. Sanga cattle, which are hybrids of taurine and indicine cattle, would
then be species hybrids. Hybrids between two species that only have minor
differences and would without doubt be classified as one species if one did not
know their evolutionary history. So the first option would be somewhat absurd.
The second
option is what I would opt for. Linnaeus’ description of Bos taurus as much as
Bojanus’ description of Bos primigenius are both rather minimalistic by modern
standards, so a clear description that accounts for all the autapomorphies of
the species of aurochs and cattle that sets them apart from other Bovini would
be useful. As a lectotype (which is the type specimen assigned to a species
based on a written description alone) I would use the rather complete skeleton
from Neumark-Nord, which is mounted an impressive attacking pose (this one).
It is very well-preserved, a typical aurochs and there is no chance that it is
intermixed with domestic cattle as it is roughly 200.000 years old. I would
also chose a few other specimen as paratypes, namely the Sassenberg cow (to
account for the differences between male and female) and the Prejlerup bull (to
cover the wide range of horn sizes within the species) and perhaps a few
others.
The species
of aurochs and cattle would then have to be labelled as Bos taurus. I think
this name is just as beautiful as B. primigenius, as it just means “cattle” and
it would include the wildtype which we call “aurochs”. On a subspecies level it
would get a bit more complicated. If you regard domesticates as taxa (which
doesn’t necessarily have to be, you could also just see them as populations
that have experienced artificial selection), taurine cattle would be Bos taurus
taurus and indicine cattle Bos taurus indicus, the aurochs would be Bos taurus
primigenius. This would raise the question if the wild mainland aurochs needs
to be subdivided into different subspecies. The latest research makes the
approach of having several mainland aurochs subspecies questionable at least. I
think “morphes” or “stages” might be more practicable. I go over this in my
upcoming book, so please stay tuned.
