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New (?) Mammalian Mitochondrial Tree
A paper from last year involves a mitogenomic tree of eutherians, and as
before, yet more names are proposed. It shall never end as any
"well-supported" and "high bootstrap" node gets a name. Next, the
Sorecomoprha and Proboscidea node will be called Longinostralia because
for some reason the codon support is higher than the Afrotheria tree.
Arnason, U.; Adegoke, J.A.; Bodin, K.; Born, E.W.; Esa, E.B.; Gullberg,
A.; Nilsson, E.; Short, R.V.; Xu X.-f.; & Janke, A. 2002. Mammalian
mitogenomic relationships and the root of the eutherian tree.
_Proceedings of the National Academy of Sciences, USA_ 99 (12):
8151-8156. - DOI# 10.1073/pnas.102164299.
Abstract: "The strict orthology of mitochondrial (mt) coding sequences has
promoted their use in phylogenetic analyses at different levels. Here we
present the results of a mitogenomic study (i.e., analysis based on the
set of protein-coding genes from complete mt genomes) of 60 mammalian
species. This number includes 11 new mt genomes. The sampling comprises
all but one of the traditional eutherian orders. The previously
unrepresented order Dermoptera (flying lemurs) fell within Primates as the
sister group of Anthropoidea, making Primates paraphyletic. This
relationship was strongly supported. Lipotyphla ("insectivores") split
into three distinct lineages: Erinaceomorpha, Tenrecomorpha, and
Soricomorpha. Erinaceomorpha was the basal eutherian lineage. Sirenia
(dugong) and Macroscelidea (elephant shrew) fell within the African clade.
Pholidota (pangolin) joined the Cetferungulata as the sister group of
Carnivora. The analyses identified monophyletic Pinnipedia with Otariidae
(sea lions, fur seals) and Odobenidae (walruses) as sister groups to the
exclusion of Phocidae (true seals)."
Here, colugos (Dermoptera) are found inside Primates, and as the
sistergroup of Simia. Arnason et al. name the clade Dermosimii. This taxon
is used to explicitly indicate a grouping exclusive of lemurs but
inclusive of colugos.
Cetartiodactyla is used to support the inclusion of whales within
Artiodactyla, whereas Artiodactyla is a paraphyletic clade excluding the
descendant Cetacea from it. Withing this clade, the name Whippomorpha is
not used, as an exclusive Cetacea + Hippopotamidae clade is recovered, and
called Cetancodonta. The origin of the name is cited as Ursing & Arnasson
(1998), _Proceedings of the Royal Society of London, Series B_ 266:
339-345. A clade Cetfereungulata is also used (Xu, Janke & Arnason, 1996:
_Molecular Biology and Evolution_ 13: 1167-1173) for Cetacea,
Artiodactyla, Perissodactyla, and Carnivora, and also including Pholidota
in the present analysis. The structure of all taxa were used as a
"definition" for Cetferungulata, and Arnason et al. suggest adding
Pholidota to this. This supports Ferae (Pholidota + Carnivora) and
Fereungulata, though maybe not in the non-cladistic manner but the "only
this type of phylogeny" manner as discussed earlier. Xenarthra are the
sister group to Afrotheria, which includes the Tenrecomorpha as the sister
group to Macroscelidea, but this group is simply listed as "African
clade." Rodentia is paraphyletic in regards to other eutherians, with rats
and mice, and voles, outside a clade formed by Afrotheria, Laurasiatheria,
and other rodents (some muroids, hystricognaths, and sciuromorphs).
Erinaceomorphs are considered the outgroup to all other eutherians. Wierd
The use of "paraphyletic" in the paper is erroneous, since it refers to
the monophyletic Primates which includes Dermoptera as "paraphyletic"
when, in fact, the strict use of monophyletic (and even "holophyletic" if
you would) applies to the phylogeny as presented.
Jaime A. Headden
Little steps are often the hardest to take. We are too used to making leaps
in the face of adversity, that a simple skip is so hard to do. We should all
learn to walk soft, walk small, see the world around us rather than zoom by it.
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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