littor...@gmail.com wrote:
> The human philtrum can only be explained IMO as the rudiment of nose-closing (not the very top, but underneath), as still can been in some extant humans (intra-species variation!), and archaic Homo was a lot more prognathic than most of us are, google "coastal dispersal Pleistocene Homo".
You are, of course, wrong.
What "extant human" populations do this? Provide evidence.
MANY mammals have a philtrum.
https://en.wikipedia.org/wiki/Philtrum
The philtrum (Latin: philtrum from Ancient Greek
φίλτρον phíltron, lit. "love charm"), or medial
cleft, is a vertical indentation in the middle
area of the upper lip, common to many mammals,
extending in humans from the nasal septum to the
tubercle of the upper lip. Together with a glandular
rhinarium and slit-like nostrils, it is believed to
constitute the primitive condition for at least
therian mammals."
In most mammals, the philtrum is a narrow groove
that may carry dissolved odorants from the rhinarium
or nose pad to the vomeronasal organ via ducts inside
the mouth.
For humans and most primates, the philtrum survives
only as a vestigial medial depression between the nose
and upper lip.
The human philtrum, bordered by ridges, also is known
as the infranasal depression, but has no apparent
function. That may be because most higher primates rely
more on vision than on smell. Strepsirrhine primates,
such as lemurs, still retain the philtrum and the
rhinarium, unlike monkeys and apes.
https://advetresearch.com/index.php/AVR/article/view/487/432
The philtrum is a median groove in the upper lip of
domestic animals (Nickelet al.,1979). It usually found
in animals that possessed a rhinarium or a nasalplane
(NP) such as carnivores and small ruminants (Nickelet
al., 1979; Evans and Christensen, 1979). The nasal plane
is a wet glabrous skin area, which covers the medial wings
of the nostrils (Nickelet al., 1979). The philtrum in such
species is deep and sometimes extends to the nostrils. On
the other hand, it’s shallow or absent in animals that
lack NP, a sequine (Nickelet al., 1979). This anatomical
association is also indicating functional correlations
between the philtrum and the NP (Hillenius and Rehorek,
2005). The philtrum proposed to drain the odoront molecules
that dissolved in the fluid covering the NP to reach the
incisive papillae and then into the nasopalatine ducts
(Wöhrmann-Repenning and Bergmann, 2001). While the
nasopalatine ducts or incisive ducts are the oro-nasal
passage of the vomeronasal duct system (VNO), the philtrum
thereby is considered the communication canal between the
NP and the VNO (Hillenius and Rehorek, 2005; Eshrah, 2019).