49-million-year-old mammal lineage found living in Africa!

DavidBrown

DavidBrown

Well-Known Member
15+ year member
I have never heard of Zenkerella until I read this story, but it seems like it should be the mammal discovery of the 21st century. It is a 49 million year old lineage that was just found alive in Africa. It seems amazing! Or is this old news to people here who follow extremely obscure mammals?

Indeed, Zenkerella is the ultimate survivor. Of the 5,400 mammal species known to science, only it and five others are the sole surviving members of ancient lineages.
Click to expand...

What are the other five mammalian "sole surviving members of ancient lineages" of which they speak?

https://www.washingtonpost.com/news...top-stories-2_sos-mammal-155pm:homepage/story
 
that's cool. I've always known Zenkerella as the scalytail which can't fly. But I've never read much about it before.

The other "sole survivors" include, I think, the Laotian Rock Rat. There was a weird non-gnawing rodent from South America discovered recently which I think is another. I'll have to do some googling later...
 
DavidBrown said:
What are the other five mammalian "sole surviving members of ancient lineages" of which they speak?
Click to expand...
this article - Scientists on the prowl for 'the ultimate Pokémon' | EurekAlert! Science News - says:

Of the about 5,400 mammal species alive today, only Zenkerella insignis and five others are the "sole surviving members of ancient lineages" dating all the way back to the early part of the Eocene epoch, 49 million years ago or more, Seiffert said. Within this select group, only Zenkerella, the monito del monte (Dromiciops gliroides) and the pen-tailed tree shrew (Ptilocercus lowii) have been given the medal "living fossil." They closely resemble what is observed in their species' fossil record. In other words, although they have evolved over time, the changes were minimal.
Click to expand...

Googling for "sole survivors of ancient lineages" gives a range of examples including the NZ Short-tailed Bat, the Banded Hare Wallaby, and the Pigmy Right Whale. So I guess it depends on how you interpret what they mean. This year the Monito Del Monte was split into three species as well, so that may also have something to do with their numbers.
 
Listed as Least Concern (LC) in the IUCN's Red List online assessment:

"This Central African species has been recorded from southern Cameroon, Equatorial Guinea (including southern Bioko Island, two specimens collected in 1989 and 1993), Congo, and Ngotto Forest in Central African Republic (on the border of the Central African Republic and Congo). It has not been recorded from Gabon or Democratic Republic of the Congo, although it is likely to occur here."

Source: Zenkerella insignis (Cameroon Scaly-tail, Flightless Scaly-tailed Squirrel)

------

Two possibly extinct species are also known from Bioko Island, Equatorial Guinea: Myosorex eisentrauti and Genetta poensis. Although the latter binomial is used in the recent literature in relation to living specimens, so it's conservation status is unclear.
 
Surroundx said:
Two possibly extinct species are also known from Bioko Island, Equatorial Guinea: Myosorex eisentrauti and Genetta poensis. Although the latter binomial is used in the recent literature in relation to living specimens, so it's conservation status is unclear.
Click to expand...
although Genetta poensis is known from only a few specimens they are so geographically spread across west Africa that it seems unlikely it is actually extinct, simply elusive. (Or confused with other species, given that it has been lumped and split several times with other genets).
 
Solenodons were around in the Cretaceous, so I would include them as survivors of an ancient lineage. There is a controversial theory that marsupial moles are dryolestids, which were thought to live from the Jurassic to Palaeocene.

https://en.wikipedia.org/wiki/Living_fossil lists the following mammals: aardvark,
Amami rabbit, chevrotain, elephant shrew, Laotian rock rat, monito del monte,
monotremes, mountain beaver, okapi, opossums, capybara, red panda, solenodon, shrew opossum, false killer whale, pygmy right whale.
Some of these are the only members of their families, while others are distinct members of large families, some of which have ancient lineages.
 
Dassie rat said:
Solenodons were around in the Cretaceous, so I would include them as survivors of an ancient lineage. There is a controversial theory that marsupial moles are dryolestids, which were thought to live from the Jurassic to Palaeocene.

https://en.wikipedia.org/wiki/Living_fossil lists the following mammals: aardvark,
Amami rabbit, chevrotain, elephant shrew, Laotian rock rat, monito del monte,
monotremes, mountain beaver, okapi, opossums, capybara, red panda, solenodon, shrew opossum, false killer whale, pygmy right whale.
Some of these are the only members of their families, while others are distinct members of large families, some of which have ancient lineages.
Click to expand...
An interesting recent article about the mitochondrial genome of solenodons being sequenced here: Scientists Sequence Mitochondrial Genome of Hispaniolan Solenodon | Biology, Genetics | Sci-News.com

The marsupial mole/dryolestid suggestion is also on this thread (from post #76) - although I am firmly not convinced by the evidence in the paper: http://www.zoochat.com/65/taxonomy-thread-376091/index6.html

I think the articles on Zenkerella mentioning five species of "sole survivors" are being selective/specific in what is being included, but it isn't very clear about what they are using as their base apart for "the early part of the Eocene epoch".
 
I'm a bit confused about the original article. The author seems to imply that Zenkerella should be placed in a separate family from the other scaly-tails, because it lacks a gliding membrane. The marsupial families Acrobatidae, Pseudocheiridae and Petauridae contain gliding and non-gliding forms. All these families were placed in the Phalangeridae, but should they be split further?
 
Dassie rat said:
I'm a bit confused about the original article. The author seems to imply that Zenkerella should be placed in a separate family from the other scaly-tails, because it lacks a gliding membrane.
Click to expand...
the article linked in the first post isn't very well written. I think the author was partly trying to make it easily-read by your average person and partly perhaps didn't really understand what she was writing about. There are better ones out there, including Researchers seek Zenkerella, an elusive scaly-tailed squirrel that has never been spotted alive by scientists which says:
Using the three whole-body specimens, scientists sampled Zenkerella's DNA for the first time. The study, published in the journal PeerJ on Aug. 16, details how researchers analyzed Zenkerella's genes using cells from cheek swabs. Then they compared the scaly-tailed squirrels' DNA with a large sample of other rodents in an online database called GenBank, which includes all rodent suborders and families.

...

Based on DNA results, the researchers determined that, contrary to expectation, Zenkerella is a very distant cousin of two scaly-tailed squirrels with webbing between their legs and elbows that allows them to glide from tree to tree. Thus, Zenkerella, who cannot glide, should be placed in the newly named Zenkerellidae family, researchers said. All three cousins are part of the superfamily of Anomaluroidea, partially because they all have a set of scales on the bottom of their tails that reportedly provide support and traction for tree climbing.
Click to expand...

Basically it is saying that Zenkerella was classed as a close relative of the gliding anomalures but that the new DNA study shows it is a sister taxon.


The original paper - which makes everything much clearer - can be read here: https://peerj.com/articles/2320/
 
Dassie rat said:
Thanks, Chli. The original paper is a lot clearer.
Click to expand...

I agree. The original paper is well worth a look. I was surprised to see that the specimens were caught in snares on the ground - I had imagined that all the scaly-tails were found exclusively in the forest canopy, perhaps Zenkerella sometimes has to come to the ground as it cannot glide.

Alan
 
The whole scaly-tail family is little-known. I wish there were more research on them, and that some zoos would make at least an effort to keep them.
 
You must log in or register to reply here.
Back
Top