Flugsaurier 2018 part 3
Since the purpose of the symposium is increase understanding of pterosaurs, I hope this small contribution helps.
Lü et al. 2018 report on two new and unnamed anurognathid pterosaurs
from China. I’m guessing the one featured today has been known for six years based on its number: JPM-2012-001.
According to Lü et al. 2018
“Based on body morphologies, anurognathid pterosaurs can be classified into two subgroups: long-tailed anurognathids (length ratio of tail to femur is greater or equal to 1) and short-tailed anurognathids (length ratio of tail to femur is smaller than 1).” The JPM specimen is a long-tailed type.
The second Chinese anurognathid, BPMC-0009,
is not shown in its entirety in Lü et al. 2018. Rather the authors focus on the tiny fourth phalanx at the wing tip (which also includes an ungual!). Lü et al. 2018 report, “The extremely reduced wing phalange 4 (its length is 4.6mm) may indicate that the so-called three wing-phalanged pterosaurs: Anurognathus (Bennett, 2007) and Beipiaopterus (Lü, 2003) may be caused by extremely reduced wing phalanx 4 and this phalanges did not preserve, and the expanded distal end of the wing phalanx 3 perhaps confirm this possibility (this distal of wing phalanx 4 is sharp and pointed).”
the basal azhdarchid, Beipiaopterus, has four wing phalanges. So does the flathead anurognathid SMNS 81928, (not congeneric with the holotype Anurognathus), which also has four wing phalanges. See them in situ here and here. All anurognathids have four wing phalanges. Regarding BPMC-0009, Jeholopterus also has a relatively small m4.4, so it may be related to the BPMC-0009 specimen. We’ll have to see the complete specimen to make that determination.
The JPM specimen
has a long tail —but it nests with the short tailed Anurognathus (holotype, Fig. 3). So there goes the earlier Lü et al. hypothesis about splitting anurognathids. Under the Lü et al. hypothesis, you will have to know that every tiny caudal bone was on the matrix surface, preserved and able to be seen. Think how easy it would be for such tiny, pollen-sized, distal caudals to be buried… or lost during taphonomy. Besides, no one wants to pull a Larry Martin, splitting or lumping taxa based on one trait. Use all 180+ traits in the large pterosaur tree (LPT). And make reconstructions to test your observations!
Anurognathids have a long history
of bad reconstruction. So does Anurognathus. Note, as in Vesperopterylus and all other anurognathids (Fig. 5), there is no trace of a giant scleral ring in the anterior half of the JPM specimen skull (Figs. 1–3, contra Bennett 2007 and the current fashion among pterosaur workers and artists). Rather, and just like related Dimorphodon, the antorbital fenestra is quite large and the orbit is right behind it.
Like the holotype Anurognathus,
(Fig. 3) the JPM-2012-0001 specimen has longer dentary teeth (deeper than the mandible), an antorbital fenestra taller than the orbit (convergent with azhdarchids and tapejarids), a tiny metacarpus and a long list of other shared traits. The JPM specimen is more gracile overall, with smaller feet, more slender wing finger, a larger sternal complex and a shorter, taller skull.
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Lü J-C, Zhou X-Y, Liu C-Y and Sun D-Y 2018. Chinese anurognathid pterosaurs. Flugsaurier 2018: the 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts:63-65.