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Re: No Cretaceous placental mammals?
Now I can answer my own questions:
Isn't there a pregnant leptictid in Messel or something?
Or am I making this up?
In Messel at least there's none; thanks to HP Trevor Dykes.
But in any case leptictids have never been reported to
have epipubes or a narrow pelvis, AFAIK.
If the Maastrichtian tooth taxon *Gypsonictops* is a
leptictid, we have placental reproduction in the Mesozoic.
Indeed leptictids lack epipubes, indeed this is autapomorphic of the
(Leptictidae + Placentalia) clade, and indeed *Gypsonictops* is a leptictid
(one of two in the matrix of Wible et al.); thanks to HP Tom Holtz. The
placental mode of reproduction must have evolved very late, apparently in
the Maastrichtian, just in time for the mass extinction.
More on the phylogenetic analysis:
- 21 characters are parsimony-uninformative; one of them is even constant.
That makes 387 rather than 408 parsimony-informative characters. Of course
that's still a lot!
- There seems to be some duplication in the matrix: for example the number
of premolars, the number of molars, and the number of postcanines are three
- All characters were unordered. Someone should have a look what happens if
this is changed. I wonder if the *Purgatorius*-*Protungulatum*-*Oxyprimus*
clade depends on this.
- I think every single named zhelestid, asioryctithere, and zalambdalestid
is in the matrix. Surprisingly, these come out as four distinct clades, with
most of the zhelestids forming one of them.
- Zalambdalestidae and Glires are very far apart, even though their
enlarged, ever-growing lower incisors were coded as homologous to bias the
results towards the assumption that Cretaceous placentals are known. As
further explained in the supplementary information, the teeth are almost
certainly not homologous: embryology says the lower gnawing tooth in Glires
is the no-longer-deciduous second incisor of the standard placental three,
while in Zalambdalestidae it is the first of the standard therian four.
AFAIK no therian with more than four lower incisors is known, so the
zalambdalestids have most likely not lost an incisor in front of the
- *Deccanolestes* (consisting of two species of Maastrichtian eutherian from
India, each named for an isolated astragalus, IIRC) is in the matrix! It
comes out as the sister-group of (Zalambdalestidae + Placentalia), far from
both Placentalia and Cimolestidae (one or two previously supported
- There are two carnivorans (*Miacis* and *Vulpavus*), the sister-group of
the crown of Cetartiodactyla (*Gujaratia* -- formerly *Diacodexis
pakistanensis* which would have made *Diacodexis* paraphyletic), and three
"mainstream condylarths" (*Hyopsodus*, *Meniscotherium*, *Phenacodus*) in
the matrix; together with *Erinaceus* (western European hedgehog, or maybe
the eastern one, I forgot), *Blarina* (a shrew), *Solenodon*, and *Eoryctes*
(an Eocene "insectivore"), this is all of "Laurasiatheria" that is in the
matrix. Someone should add more.
- Especially, *Apheliscus* and friends, found close to Macroscelidea in
other analyses, are not in.
- *Potamogale*, the only afrosoricidan, comes out as the sister-group of
*Eoryctes* (see above), but all other afrotherians form a clade:
((*Procavia* [hyrax] + *Moeritherium* [proboscidean]) + (*Orycteropus*
[aardvark] + *Rhynchocyon* [elephant shrew])) -- and that without Eocene
hyraxes, Eocene elephant shrews, or apheliscines in the matrix!
- Interestingly, the three "mainstream condylarths" form a clade. I wonder
if adding perissodactyls would change that.
- Except for the "condylarths" (the mentioned ones plus *Protungulatum* and
*Oxyprimus*), no representatives of Paleogene-only "orders" are included. Is
*Uintatherium* a Giant Horned Bunny? Are taeniodonts "cimolestans"? I smell
a couple of surprises waiting to be discovered.
- Over the next few years I expect a series of papers to be built on this
matrix. Now that people who want to investigate eutherian phylogeny no
longer need to build their own matrix from scratch, but can simply add taxa
and maybe a handful of characters to an existing one, the motivation for and
the ease of finding out where, say, the South American "ungulates" belong or
which planet the bibymalagasy comes from have without doubt greatly
In other words, this paper was just the beginning! :-)