What would bats be, if Chriacus was not known?

This is a lesson in taxon exclusion…
to see where select clades would nest in the absence of their proximal taxa. This might find highly convergent clades or taxa.

Bat origins
have befuddled traditional paleontology. In the large reptile tree (LRT, 1241 taxa) bats arise from a sister to Chriacus, an arboreal mammal, nesting with dermopterans and pangolins. We looked at bat origins most recently here and at earlier posts in that series.

Figure 1. Subset of the LRT focusing on basal placentals, including bats.

Figure 1. Subset of the LRT focusing on basal placentals, including bats.

With a large gamut cladogram
we can cherry-delete taxa to see where bats would nest, if not with Chriacus.

  1. Chriacus deleted: no change, bats still nest with pangolins and colugos.
  2. Dermopterans and pangolins deleted: bats nest with with lemurs, with loss of resolution leading to 5 MPTs. This follows the ‘flying primate‘ hypothesis (Pettigrew 1986, Pettigrew  et al. 1989) for bat origins — but that only works with taxon exclusion, so it is invalid.
Figure 3. Subset of the LRT focusing on basal placentals, including bats.

Figure 3. Subset of the LRT focusing on basal placentals, including bats.

Let’s delete mega-bats and then delete micro-bats.

  1. Pteropus deleted: no change, microbats still nest with pangolins and colugos.
  2. Microbats deleted, Pteropus/Rousettus restored: Pteropus/Rousettus nests between colugos and Chriacus + pangolins.

Taxon exclusion
has been the number one problem in traditional paleontology. That’s why the LRT includes such a wide gamut of taxa. The result is a minimizing of taxon exclusion and the problems that attend it.

We’ll look at other former enigmas in future blog posts
and run deletion tests on their proximal outgroups as well.

References
Pettigrew JD 1986. Flying primates? Megabats have the advanced pathway from eye to midbrain. Science. 231(4743): 1304–1346.
Pettigrew JD, Jamieson BG, Robson SK, Hall LS, McAnally KI, Cooper HM 1989. Phylogenetic relations between microbats, megabats and primates (Mammalia: Chiroptera and Primates). Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 325 (1229): 489–559.

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