Banguela: a new pterosaur by a first-time author

Congratulations to Jaime Headden, who, along with Hebert Campos, had their discovery of Banguela oberlii, a toothless dsungaripterid NMSG SAO 251093, published. It’s a big jaw tip, producing an estimated skull length of 2 feet (60cm). That’s a bit more than a 50cm Dsungaripterus skull. Missing here is the jaw tip, which we learned earlier is a single tooth.

Figure 1. Banguela from several angles. Note the lack of teeth on this dsungaripterid.

Figure 1. Banguela from several angles. Note the lack of teeth on this dsungaripterid.

 

The Brazilian nickname ‘Banguela’ is commonly given to toothless people (Fig. 2), even though most retain a few teeth.

Figure 2. The original meaning of "Banguela", or what you'll find if you don't add the word "pterosaur" to your Google search.

Figure 2. The original meaning of “Banguela”, or what you’ll find if you don’t add the word “pterosaur” to your Google search.

JH mentioned, “An interesting rule of biology says when animals lose a feature, it cannot be regained. This is called Dollo’s Law, and it tells us about why birds don’t regrow teeth.”

Dollo’s Law needs to be brought up more often, like when pterosaurs are supposed to grow gigantic wing (4th) fingers from the vestiges most archosaurs have. Better to look for those sorts of fingers where they actually are, in the Lepidosauria.

JH reported, “Banguela oberlii is here hypothesized to be a derived dsungaripterid, though in our phylogenetic analysis (Headden & Campos, 2014) the new taxon was placed basal to other dsungaripterids. Further analysis supports a deeper nesting, but this work was not prepared at the time of publication.”

The large pterosaur tree nested dsungaripterids between toothy basal germanodactylids and toothless shenzoupterids and tapejarids, which is probably why Banguela initially nested basal, closer to other toothless clades.We also learned that basal taxa in virtually all pterosaur clades were tiny. So it is a good bet that big Banguela was a terminal, rather than a basal, taxon. There was a trend toward tooth loss in this clade of germanodactylia. Not surprising, but still wonderful, to see a “toothless” dsungaripterid. Any X-rays of those jaws planned?

References
Headden JA and Campos HBN 2014. An unusual edentulous pterosaur from the Early Cretaceous Romualdo Formation of Brazil. Historical Biology [Published online ahead of print]: 1-13. doi: 10.1080/08912963.2014.904302

More info online here at J. Headden’s blogpost.

 

 

 

 

11 thoughts on “Banguela: a new pterosaur by a first-time author

  1. Glad the paper is useful to you. I’m not sure the value of this being my first paper is meaningful, though.

    “Banguela” has a lot of little uses in Portuguese, and we felt the combined use of toothlessness and old age worked well. It also illustrates progressive toothloss in dsungaripterids as the lineage aged, a neat little touch in our opinions.

    I note you bring up my reference to Dollo’s Law — discussed on my blog, but not our paper — but I’m unsure why. Dollo’s Law is a general rule, a null argument, but it doesn’t necessarily hold true in all cases. Birds lack teeth, but as I wrote in my blog may be induced to regrow them through manipulation of their genes OR supplanting dentigenous tissues onto the embryonic jaw, which tiself would cotnradict Dollo’s Law. It’s a neat rule … when it applies. My argument was about the loss of dentition and the unlikelihodd of recurrent growth of dentition, which is illustrative of the multiple phases of tooth loss in pterosaurs and possibility that Banguela oberlii is derived.

    As I wrote, future work supports a more nested position, but still manages to get Banguela oberlii as a dsungaripterid, and further supports most of the topology presented in the paper.

  2. A first paper is an achievement. “:Goobeegoo, one of us” (you might enjoy googling the reference)
    Dollo’s law reminds us that vestigial digits don’t turn into wings, as noted above, and IMHO does work for toothlessness in pteros, so you’re right regarding Banguela’s derivation IMHO.

    • I think the best contemporary take on Dollo’s law/rule is that regulatory genes can be retained, silenced but reversible, for such complex structures as teeth in birds or eyes in cave organisms, but that in the absence of selection for functioning teeth, eyes, etc, multiple genes rapidly drift from the original functional complex. So a contemporary bird might develop tooth buds, but these would not instantly become functional teeth.

      This all seems reasonable, but there are cases of evolutionary reversal involving complex and functioning structures — the most compelling that I know of is in the stick insects [phasmids]. If we trust DNA phylogenies — and I do here, functioning wings and flight has been restored from complete aptery in multiple lineages.

      So could pterosaurs re-acquire functioning teeth? A present-day Dollo might ask how long they were gone, how much genetic water under the dam.

  3. Phylogenetic analysis is good for revealing reversals, such as losing and gaining vertebrae and ribs, the small metacarpal on Jiangopterus and that vestigial tail that constantly bothers me whenever I sit down to type. I agree, I know of no cases where toothless pterosaurs regain marginal teeth.

  4. Without an alveolus to root your hypothesis (ah-hah, so punny) of a single tooth it is not the most parsimonious explanation to the morphology of the tip of the dentaries.

  5. Rob, please look more closely at the specimens, and trace their ancestry, like at reptile evolution.com. Then you’ll see how two teeth become one at the jaw tips. This was also covered earlier at pterosaurheresies.

    • They’re very tiny when that happens. My guess is one becomes dominant and the other a vestige. With lateral view crushing, it’s hard to tell. And, of course you know about the central dentary tooth on Istiodactylus. These things happen.

      • Do you have a developmental model based on growth of teeth in living tissues that demonstrates this? And as for that “tooth,” it’s called an “odontoid process” by Martill and was assumed to be bone. Only YOU, as far as I can tell, calls it an actual “tooth.” That’s not evidence, nor is it particularly sound, as it still fails to take into account the development of a midline tooth. And yes, there are animals with midline teeth, and for the most part this is due to assymetry, not “teeth merging” — especially ACROSS the midline.

  6. I base what I say on observation of many pterosaurs, tracking their evolution.
    The beauty of science is you can follow the method and see for yourself. You’ll note that medial teeth rotate anteriorly earlier in the evolution of the pointed snout pterosaurs. And I remind you, I did not say teeth merge. I have documented several examples in earlier posts of this finding, sometimes with the tooth in place. Sometimes when it is missing. I did not examine these for dentine or enamel. IMHO these would be permanent teeth, different than other reptile teeth, and perhaps, because they were subject to wear, may have had a different growth and structure. I raise the issue and hope someone will either confirm or reject the hypothesis. That’s the process.

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