Riley Black (formerly Brian Switek) wrote:
in the subhead of her Scientific American blogpost, “New pterosaur was fossilized with a ridiculous grin.”
but in situ (Fig. 1) it’s not the first or only one. And when reconstructed (Fig. 2) the grin is gone.
On the plus side,
the Aptian (Early Cretaceous) skull attributed to Nurhachius is complete, which is always wonderful, especially for such fragile skulls.
Then Black’s subhead reports,
“A skull found in China reveals a previously unknown flying reptile.” Well, if you read the text, not really. The authors consider the new specimen congeneric with the holotype Nurhachius (Fig. 3).
The teeth are like those of other istiodactylids in shape and distribution,
but when you put the two Nurhachius skulls together (Fig. 3), the two are not congeneric, so far as can be determined from available data. The mandible is not as robust in the new specimen, the rostrum is not as long. There in indication of the broader rostral tip found in Istiodactylus and other istiodactylids, nor is the orbit subdivided by circumorbital processes. The referred specimen preserves post orbital and cranial bones unknown in the holotype.
The genus holotype is
Nurhachius ignaciobritoi (Wang, Kellner, Zhou & Campos 2005; Fig. 3) IVPP V-13288, Early Cretaceous, skull length ~30 cm, ~2.5 m wingspan). The wings are long. The free fingers and toes are tiny. The sternum portion of the sternal complex is deep.
From the abstract:
“A revised diagnosis of the genus Nurhachius is provided, being this taxon characterized by the presence of a slight dorsal deflection of the palatal anterior tip, which is homoplastic with the Anhangueria and Cimoliopterus. N. luei sp. nov. shows an unusual pattern of tooth replacement, with respect to other pterodactyloid species.”
The phylogenetic analysis presented by Zhou et al. 2019
is not worth showing or discussing due to the inclusion of Scleromochlus (a basal bipedal croc) and the exclusion of dozens of relevant pterosaur and fenestrasaur taxa. The new Nurhachius nests in the large pterosaur tree (LPT, 240 taxa), basal to other istiodactylids, next to, but not with Nurhachius. Proximal outgroup taxa include Coloborhynchus and Criorhynchus.
Zhou X, Pegas RV, Leal MEC and Bonde N 2019. Nurhachius luei, a new istiodactylid pterosaur (Pterosauria, Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of Chaoyang City, Liaoning Province (China) and comments on the Istiodactylidae. PeerJ 7:e7688 DOI 10.7717/peerj.7688
So many pterosaurs have ridiculously tiny feet and free fingers — but this is based on our own solid-boned experience. I wonder if it’s possible, in principle, to estimate the body mass of particular pterosaurs by depth of impression. [Or has this been done?]
It may be that mass could be estimated for particular ichnites, even without candidate pterosaurs if the soil type is well established..
Has not been done yet, to my knowledge. Remember the substrate is now stone. Hard to tell what the original water content was. Or is there a way to do so?
The obvious place to start would be beach sand — mechanical qualities are pretty well scaled to particle size when wet [assuming that only wet sand is likely to preserve ichnites.. And you would like to have several other types of prints: birds, theropods.
If anyone ever finds ichnites of a big arzharchid preserved in wet sand, it should give an upward limit of body mass. A good student project. I can imagine strapping pterosaur feet on geese and ostrichs or working with sandbags and a couple pair of stilts..
Kidding aside, when a structure seems strange by everyday experience, it’s telling you something.
This just in: When the drywall guy goes fishing: https://www.facebook.com/FishHeadsFishingMemes/photos/a.1720447294894258/2468975690041411/?type=3&theater