Read the Beforeitsnews.com story here. Advertise at Before It's News here.
Profile image
Story Views
Now:
Last hour:
Last 24 hours:
Total:

Why hedgehogs and moonrats are not good outgroup taxa for tree shrews

% of readers think this story is Fact. Add your two cents.


Li and Ni 2016 put together a few Oligocene teeth
and mandibles and introduced us to tiny Ptilocercus kylin (Fig. 1), a sister to the extant treeshrew, Ptilocercus lowii (Fig. 1). Unfortunately, too little is known of the new species to add it to the large reptile tree (LRT, 1786+ taxa, subset Fig. 4). The posterior premolar is the largest tooth in the mandible in both species. I could not find that trait elsewhere among tested taxa.

Figure 1. Several specimens of Ptilocercus kylin (Oligocene) matched to Ptilocercus lowii (extant). ” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2021/01/ptilocercus_skull588-1.gif?w=300″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2021/01/ptilocercus_skull588-1.gif?w=584″ class=”size-full wp-image-52385″ src=”https://pterosaurheresies.files.wordpress.com/2021/01/ptilocercus_skull588-1.gif?w=584&h=407″ alt=”Figure 1. Several specimens of Ptilocercus kylin (Oligocene) matched to Ptilocercus lowii (extant).” width=”584″ height=”407″ />

Figure 1. Several specimens of Ptilocercus kylin (Oligocene) matched to Ptilocercus lowii (extant).

Li and Ni 2016 provided a cladogram
(Fig. 2) in which they ‘selected’ (their word, not mine) a moonrat (Echinosorex) and hedgehog (Erinaceus) as outgroup taxa to the tree shrews and their proximal allies.

Figure 2. Cladogram from Li and Ni 2016 showing their inappropriate selection for an outgroup, the hedgehog, Erinaceus. ” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=300″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=584″ class=”size-full wp-image-52365″ src=”https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=584&h=434″ alt=”Figure 2. Cladogram from Li and Ni 2016 showing their inappropriate selection for an outgroup, the hedgehog, Erinaceus.” width=”584″ height=”434″ srcset=”https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=584&h=434 584w, https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=150&h=111 150w, https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg?w=300&h=223 300w, https://pterosaurheresies.files.wordpress.com/2021/01/tree-shrew-li_ni2016_cladogram588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 2. Cladogram from Li and Ni 2016 showing their inappropriate selection for an outgroup, the hedgehog, Erinaceus.

Li and Ni 2016 report,
“The phylogenetic analysis was based on a data matrix derived from published data in ref. 12 
[= Ni et al. 2013]. In total, 1857 characters were scored for 177 taxa. The 1857 characters comprise 485 dental, 202 cranial, 309 postcranial, 203 soft tissue characters and 658 molecular characters. Two erinaceid insectivores, Erinaceus europaeus and Echinosorex gymnura, were selected as outgroup taxa. The ingroup comprises 13 treeshrews, 28 flying lemurs and plesiadapiforms, 45 lemuriforms and adapiforms, 40 tarsiiforms and 49 anthropoids. Of these taxa, 47 are extant species.”

Never ‘select’ = ‘cherry-pick’ outgroup taxa. Always let your wide gamut cladogram tell you which taxa are outgroups for your more focused studies.

Unfortunately, Li and Ni chose derived taxa, a hedgehog and a moonrat, both members of the gnawing clade, Glires, as their outgroup clade. In the LRT (subset Fig. 4) all members of Glires are derived from the tree shrew, Tupaia. So hedgehogs and moonrats are not basal, primitive outgroups to all tree shrews. Just the opposite. Tree shrews are among their ancestors.

That mistake puts a small crimp on any results Li and Ni obtain. In the LRT basal members of the clade Carnivora would be more suitable as outgroup taxa. Or, better yet, they could have taken it back one or two more nodes to the outgroup taxon for the clade Placentalia, Caluromys (Fig. 3). This extant arboreal wooly opossum, looks and acts more like a placental tree shrew…with a pouch.

Figure 1. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia. ” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=197″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=584″ class=”size-full wp-image-49941″ src=”https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=584&h=888″ alt=”Figure 1. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia.” width=”584″ height=”888″ srcset=”https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=584&h=888 584w, https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=99&h=150 99w, https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg?w=197&h=300 197w, https://pterosaurheresies.files.wordpress.com/2020/10/genetta_caluromys_tupaia588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 3. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia. See the LRT for node placement.

Li and Ni 2016 report,
“Approximately 20 hours were required to finish the unconstrained search. More than 769 billion rearrangements were examined. Forty-seven trees with a best score of 13067 were retained. Nearly 21 hours were required to finish the backbone-constrained search. More than 728 billion rearrangements were examined. Twenty trees with a best score of 13141 were retained. The best trees and the strict consensus of these trees were described in PAUP.

The Li and Ni 2016 cladogram would have been better served by deleting all molecular data and adding more basal placental taxa, as in the LRT (Fig. 4). Dental traits are subject to reversals and convergences. Try to use the whole skeleton and use fewer dental traits, as in the LRT. Usually just a few minutes are required to get nearly full resolution of subsets within the LRT.

Figure 3. Subset of the LRT focusing on the clade Scandentia (tree shrews) and the three arboreal clades that arise from it. ” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=109″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=372″ class=”size-full wp-image-45210″ src=”https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=584&h=1606″ alt=”Figure 3. Subset of the LRT focusing on the clade Scandentia (tree shrews) and the three arboreal clades that arise from it.” width=”584″ height=”1606″ srcset=”https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=584&h=1606 584w, https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=55&h=150 55w, https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg?w=109&h=300 109w, https://pterosaurheresies.files.wordpress.com/2020/05/scandentia-volitantia.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 4. Subset of the LRT focusing on the clade Scandentia (tree shrews) and the three arboreal clades that arise from it. See the LRT for more basal taxa.

Li and Ni report,
“We define the Order Scandentia as a crown group, including the clade stemming from the most common ancestor of extant ptilocercids and tupaiids.”

This definition for Scandentia = Placentalia sans Carnivora + basal Placentalia (in the LRT). So it works! This definition is monophyletic in the LRT. Of course, that means the order Scandentia also includes odontocetes, hedgehogs, rats, multituberculates, elephants, humans, giraffes and ground sloths, etc. etc…. everything, but Carnivora and some arboreal post-marsupial civets. Clearly that was not their intention. So… what do we do with this?


References
Li Q and Ni X 2016. An early Oligocene fossil demonstrates treeshrews are slowly evolving “living fossils”. Sci. Rep. 6, 18627; doi: 10.1038/srep18627 (2016).
Ni X, Gebo DL, Dagosto M, Meng J, Tafforeau P, Flynn JJ and Beard KC 2013.The oldest known primate skeleton and early haplorhine evolution. Nature 498, 60–64. This paper is about Archicebus achilles, a tarsier, we looked at earlier here.



Source: https://pterosaurheresies.wordpress.com/2021/01/06/why-hedgehogs-and-moonrats-are-not-good-outgroup-taxa-for-tree-shrews/


Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world.

Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.

"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.

Please Help Support BeforeitsNews by trying our Natural Health Products below!


Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST


Order by Phone at 888-809-8385 or online at https://www.herbanomic.com M - F 9am to 5pm EST


Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!

HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation

Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.

MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser!  Cleans out toxic buildup with oxygen! 
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover -  Reduces Smart Meter radiation by 96%!  (See Video)

Immusist Beverage Concentrate - Proprietary blend, formulated to reduce inflammation while hydrating and oxygenating the cells.

Report abuse
Loading...
Loading...

Comments

Your Comments
Question   Razz  Sad   Evil  Exclaim  Smile  Redface  Biggrin  Surprised  Eek   Confused   Cool  LOL   Mad   Twisted  Rolleyes   Wink  Idea  Arrow  Neutral  Cry   Mr. Green

MOST RECENT
Load more ...

SignUp

Login

Newsletter

Email this story
Email this story

If you really want to ban this commenter, please write down the reason:

If you really want to disable all recommended stories, click on OK button. After that, you will be redirect to your options page.