Evolution of Hymen in Animals: Overview & Research

[Buzz Bloom]

TL;DR Summary

What creature was the common ancestor or all animals with a hymen?

I made an effort to find an answer to this question on the Internet, but I was unsuccessful. I did learn that there are some researchers who report that there are many living non-human animals with a hymen, but also that this may be controversial. In particular:

https://www.thenakedscientists.com/forum/index.php?topic=16775.0​

This list is from our friends at Wikipedia! http://en.wikipedia.org/wiki/Hymen​

These animals all have a hymen:​

Squirrels ​

Antelopes ​

Gazelles ​

Frogs ​

Lake Trouts ​

Dalmations (not labs) ​

Parakeet ​

Robins (but not cardinals) ​

Bats ​

Cats ​

Chimpanzees ​

Clownfish, but not other species of fish ​

Dogs ​

Slugs ​

Elephants ​

Llamas ​

Galago (Bush babies) ​

Guinea pigs ​

Horses ​

Zebras ​

Lemurs ​

Manatees ​

Moles ​

Rats ​

Seals ​

Toothed whales ​

Chinchillas ​

Platypus ​

Narwhals ​

Alpacas ​

Bobolinks ​

Clams ​

White Footed Deer Mice ​

Meerkats ​

Moose ​

Ponies ​

Rattlesnakes ​

Shrews ​

Ladybird ​

I was unable to find any animals from this list in the Wikipedia article.
I hope someone can post an answer or a reference.

 

[Vanadium 50]

The common ancestor of clams and moose is some nephrozoa that lived 560-700M years ago. However, this clade contains pretty much every animal large enough to see and many that are not.

 

[BillTre]

It would be informative to know which animals don't have a hyman.
This would permit a better phylogenetic analysis of whether or not the hyman arose once and was inherited by all descendants (perhaps with occasional loses?).
As @Vanadium 50 wrote the clade including the animals you listed includes almost all animals, which leads to the question of whether or not the trait arose once or multiple times.
Presumably (means I am guessing) there is some strong selection for a hyman (maybe inreased protection of the germ line cells until access to them is needed) which could either select for retention of the trait once formed or independent evolution (convergent evolution) of the trait multiple times.
@Laroxe might know something of its functional importance.

 

[phyzguy]

What do you even mean when you say that egg laying animals with external fertilization, like clams and slugs, have a hymen?

 

[willem2]

Summary:: What creature was the common ancestor or all animals with a hymen?

I made an effort to find an answer to this question on the Internet, but I was unsuccessful. I did learn that there are some researchers who report that there are many living non-human animals with a hymen, but also that this may be controversial. In particular:
https://www.thenakedscientists.com/forum/index.php?topic=16775.0This list is from our friends at Wikipedia! http://en.wikipedia.org/wiki/Hymen

If you quote a forum post from 2008, which quotes wikipedia, you should look if that's still up there.
The current version only lists chimpanzees, elephants, manatees, whales, horses and llamas.
There are 2 references to books, that give a few more species, all of them are mammals.

The list of animals with a hymen quoted in the forum post, appears in this version from 2008
https://en.wikipedia.org/w/index.php?title=Hymen&oldid=236090552
but no references are given.

 

[BillTre]

Another approach to this question might be a genetic/molecular analysis of the genes/gene products involved in it generation.
This kind of data could provide indications of the hyman's method of development was conserved or not.

What do you even mean when you say that egg laying animals with external fertilization, like clams and slugs, have a hymen?

Good question. I am guessing it means a closure to the passage to where the eggs are kept/develop prior to their use.

 

[Buzz Bloom]

What do you even mean when you say that egg laying animals with external fertilization, like clams and slugs, have a hymen?

Hi phyzguy:

I think you misunderstood that I did not claim that the list was correct, or that I was claiming the source I quoted was correct. I have no knowledge about this topic. I stated the thread because I was hoping there are PFs participants who have this knowledge. Several of the responding posts seem to show it.

Regards,
Buzz

 

[Buzz Bloom]

If you quote a forum post from 2008, which quotes wikipedia, you should look if that's still up there.
The current version only lists chimpanzees, elephants, manatees, whales, horses and llamas.
There are 2 references to books, that give a few more species, all of them are mammals.

The list of animals with a hymen quoted in the forum post, appears in this version from 2008
https://en.wikipedia.org/w/index.php?title=Hymen&oldid=236090552
but no references are given.

Hi will:
I am impressed that you could recreate the 2008 version of the Wikipedia article. I know about looking at "Talk" and "View History", but I did not know that one could construct and earlier version from these sources. Thank you for bringing that to my attention.

I also noticed the reference to the two books which I will try to borrow from the local library network.

https://archive.org/details/storyofv00cath​

https://books.google.com/books?id=shq1AAAAIAAJ&dq=Virgin:+The+Untouched+History&q=toothed+whales​

Regard,
Buzz

 

[Buzz Bloom]

My Bad. Accidentally made a duplicate of a post.

 

[Buzz Bloom]

The common ancestor of clams and moose is some nephrozoa that lived 560-700M years ago. However, this clade contains pretty much every animal large enough to see and many that are not.

Hi Van:

Since the posts have led to a correction the 2008 long list of animals with a hymen, I am hoping you might be able to post or cite a reference for the common ancestor of the shorter list:

chimpanzees, elephants, manatees, whales, horses and llamas.​

Regards,
Buzz

 

[phyzguy]

Hi phyzguy:

I think you misunderstood that I did not claim that the list was correct, or that I was claiming the source I quoted was correct. I have no knowledge about this topic. I stated the thread because I was hoping there are PFs participants who have this knowledge. Several of the responding posts seem to show it.

Regards,
Buzz

OK. You should certainly drop the non-verterbrates off your list. I would limit your list to just mammals, or possibly mammals and birds. As @Vanadium 50 said, mammals and molluscs are so distantly related that I think any comparisons of small variations in body plan like this are meaningless. Mammals and molluscs are so far apart that they are even reversed in which end of their respective guts is the mouth and which end is the anus (see protostomes vs deuterostomes).

 

[jim mcnamara]

1. what exactly are you trying to figure out? Not how to do it -- this sounds like a question about something else entirely that went off the rails. IMO.

2. a more useful approach is ontogeny via embryonic tissue development, assuming this is what you really want. @phyzguy is alluding to that.

Find a book on Comparative Vertebrate Anatomy to start with. BTW this subject is so very old I had the course as an undergrad... You probably will need a reference for embryology as well. @BillTre seems like a good source for that. Or both references.

Example:
https://www.nature.com/articles/152088a0

Try Amazon or a college library - that title is really old.
Note: an older term for that tissue in non-mammalian vertebrates usually involves a discussion of 'cloaca'

 

[Vanadium 50]

I am hoping you might be able to post or cite a reference for the common ancestor of the shorter list

With all due respect, why should I look this up for you? Why can't you look this up yourself?

 

[Buzz Bloom]

With all due respect, why should I look this up for you? Why can't you look this up yourself?

Hi Van:

I am not familiar with the proper online tools for doing this kind of research. I found

https://en.wikipedia.org/wiki/Last_universal_common_ancestor#References​

which lists 56 items. I am hoping that you might be able to recommend just a few of these, or possibly another source for doing this kind of research.

Regards,
Buzz

 

[Vanadium 50]

You mean to tell us looking up "Mammal" on Wikipedia is too hard for you? There's even a picture.

 

[Buzz Bloom]

You mean to tell us looking up "Mammal" on Wikipedia is too hard for you? There's even a picture.

Hi Van:

Thank you for the suggestion. I was trying various searches, one of which was

https://en.wikipedia.org/wiki/Evolution_of_mammals .​

That took a while before I realized it was not helpful.

Regards,
Buzz

 

[Vanadium 50]

Don't see why. It has practically the same picture. Right under "Evolution of major groups of living mammals"

 

[Ygggdrasil]

For evolutionary relationships between organisms, here's a good online resource: http://tolweb.org/tree/

 

[Buzz Bloom]

Don't see why. It has practically the same picture. Right under "Evolution of major groups of living mammals"

Hi Van:

I confess that I may well be on the wrong track, but I have now found several sources that tell me the same basic information. Specifically, the LUCA belongs to (1) the clade Boreoeutheria and (2) the Placentalia, one of the three extant subdivisions of the class Mammalia.

It is then clear that the LUCA belongs to these two categories of classification. I can make two guesses about this.
(1) All (or almost all) of the descendant species of this LUCA have a hymen.
(2) A very large majority of these descendant species lost the hymen.

I hope someone can make a suggestion about how it can be determined which of these two guesses is correct.

I also hope that someone can suggest how I might determine which small subcategory of extinct subcategories of Boreoeutheria and/or Placentalia contain the LUCA.

If (2) is correct, I also hope that someone can suggest how I might find a plausible explanation about why the living mammal species with a hymen kept the hymen while the greater number of species failed to do so.

Regards,
Buzz

 

[Laroxe]

The only biological function of the hymen is to separate The developing uterus and vagina, develops in the fetus from two sinovaginal bulbs which fuse and form a solid plate of tissue. When this plate is formed the central cells are removed to form the lumen of the vagina. The lower part of the vagina, the vaginal vestibule develops from the urogenital sinus which has its own developmental pathways. The hymen develops as a solid barrier to separate these areas. In common with a number of other structures in a baby prior to birth this barrier is removed and it perforates, failure to do this is a pathological condition.

At birth in humans the tissue that is left is simply a remnant of a embryonic developmental structure. I don't really have much idea about its presence in other species but it makes sense that such a structure will be present at least in mammals during development but it would have to be perforated at the very least at birth. As it has no real function after birth basically its a matter of how efficiently the tissue is removed to describe it as having a hymen, this could be highly variable. Humans have webbed finger and toes in utero but its all removed before birth, in most.
Its hard enough to find good information about the hymen in humans, trying to find cross species research won't be easy, it generally just gets mentioned in passing. The link is to a slide share by a surgeon, they seem to have the most interest in this, its mentioned on slide 71-72-73 and not much I'm afraid. The second link might be more helpful,- might.


https://static1.squarespace.com/sta...27/Function+of+the+hymen.+Med+Hypoth+1996.pdf