A Jurassic squid choking hazard for Rhamphorhynchus

Hoffmann et al. 2020 reported in no uncertain terms,
“Pterosaurs ate soft-bodied cephalopods (Coleoidea).”

Immediately after, Hoffmann et al. dialed it back a bit,
when they wrote, “Here, we report the first evidence of a failed predation attempt
by a pterosaur on a soft-bodied coleoid cephalopod.”

Based on size alone,
the squid (PIMUZ 37358) was more than a mouthful according to this ‘to scale’ diagram (Fig. 1)…at least more than a stomachful.

Ask yourself:
could a Rhamphorhynchus of that size (none were larger) eat a squid of that size? Did the pterosaur fail at predation? Or did it change its mind after biting the squid out of curiosity or boredom and losing a tooth in the process?

Figure 1. Plesioteuthis squid in situ with tooth. Reconstructions of Plesioteuthis (above) and the n81 specimen attributed to the largest known Rhamphorhynhcus, which has a matching tooth. The question is: could that pterosaur eat that squid? Or did it change its mind after biting the squid?

Figure 1. Plesioteuthis squid in situ with tooth. Reconstructions of Plesioteuthis (above) and the n81 specimen attributed to the largest known Rhamphorhynhcus, which has a matching tooth. The question is: could that pterosaur eat that squid? Or did it change its mind after biting the squid? At the very top is the hard tissue gladius of the squid to scale. That’s a hard part that would have been especially hard to swallow.

You be the judge.
Hoffmann et al. 2020 have provided the pertinent information. Above are the predator and “prey” to scale. Other Rhamphorhynchus specimens are smaller, and the tooth could have fallen from a different alveolus (a larger tooth) on a smaller specimen. Lots of variables and unknowns here. Also consider the difficulty of swallowing that long gladius, a hard part homologous with the cuttle bone in a cuttlefish.

In any case,
watch what headline you put on your paper. Here the authors went for maximum impact. If, like these authors, you have to dial it back in the second sentence of your abstract,  maybe a more conservative headline should reflect that assessment. After all, a dietary mainstay is indeed different than a curious nibble… and relative size matters.

We looked at other pterosaur choking hazards
earlier here. Pterosaurs likely swallowed their prey whole. There is no indication that they tore squids apart, creating bite-sized pieces. Likewise there is no indication that pterosaurs were able to expand their stomach to accommodate oversize prey (Fig. 1).


References
Hoffman R, Bestwick J, Berndt G, Berndt R, Fuchs D and Klug C 2020. Pterosaurs ate soft-bodied cephalopods. http://www.nature.com/scientificreports (2020) 10:1230 | https://doi.org/10.1038/s41598-020-57731-2

SVP abstracts – Daylight and lowlight Solnhofen pterosaurs

Cardozo, Sobral and Rodriques 2019 bring us
a new look at the vision of Solnhofen (Late Jurassic) pterosaurs.

From the abstract:
“Recent taxonomic reviews suggest that up to twelve genera of pterosaurs might have been present there.” 
Up to? There are twice a dozen distinct Rhamph-like taxa in the first row of figure 1, ignoring the other Solnhofen ‘wastebasket’ taxa Pterodactylus, Scaphognathus, Ctenochasma, Archaeopteryx, etc.
Traditional workers don’t count the little ones. Specialists don’t look closely at all the specimens. They ignore many. Some distinct taxa are found within traditional taxa like, Pterodactylus, Rhamphorhynchus and other generic wastebaskets. According to the LPT, no two pterosaurs scoring the same except for a juvenile/adult pairing in the Rhamphorhynchus wastebasket (Fig. 1).
Figure 3. Bennett 1975 determined that all these Rhamphorhynchus specimens were conspecific and that all differences could be attributed to ontogeny, otherwise known as growth to maturity and old age. Thus only the two largest specimens were adults. O'Sullivan and Martill took the brave step of erecting a new species. The n52 specimen is at the lower right. Click to enlarge.

Figure 1. Bennett 1975 determined that all these Rhamphorhynchus specimens were conspecific and that all differences could be attributed to ontogeny, otherwise known as growth to maturity and old age. Thus only the two largest specimens were adults. O’Sullivan and Martill took the brave step of erecting a new species. The n52 specimen is at the lower right. Click to enlarge.

Cardoza et al. continue:
“Even though many have been recovered from different chronostratigraphic 
units, the high taxonomic diversity and morphological disparity still suggest specializations that reflect distinct ecological roles. An endocast analysis of Pterodactylus antiquus, together with a literature review of the anatomy and ecology of these taxa, suggest interesting niche partitions.”
“Pterodactylus, Scaphognathus, and Rhamphorhynchus were generalist taxa that lived on
coastal areas and fed on fishes and small invertebrates.”
The authors are ignoring the distinct morphologies of these three genera and are not splitting up the small, medium and large taxa. Nor are they considering the distinct niches between adults and their 8x smaller hatchlings.
The descendants of Scaphognathus.

Fig. 2. The descendants of Scaphognathus. Note the size reduction followed by a size increase.

Cardoza et al. continue:
Their niche, however, did not overlap completely: our analysis corroborates a previous study that Pterodactylus had photopic
[daylight] vision, in contrast to the scotopic [dusk/night vision] type of Rhamphorhynchus. Scaphognathus was also photopic, but the different dentition indicates it was not preying on the same items as Pterodactylus.
Other taxa have been regarded as more specialists.
“Germanodactylus has been proposed as a durophage, based mostly on the lack of teeth on the tips of the rostrum and mandible, and therefore also likely preyed on different items than Pterodactylus. Anurognathus, Ctenochasma, Gnathosaurus, and Cycnorhamphus represent highly specialized taxa. Anurognathus was probably an aerial insectivore, with moderately curved unguals that are consistent with a scansorial habit, thus suggesting it inhabited forested areas. Ctenochasma and Gnathosaurus were filter feeders and their different sizes might have prevented, at least to some extent, niche overlap. The diet of
Cycnorhamphus is more disputed: it has been proposed as a durophage, a jellyfish specialist, or a generalist feeding on fishes and insects. In any case, its uniquely curved mandible with teeth only on the distal tip implies a different feeding niche from Solnhofen generalist pterosaurs. Lastly, the endocast of Diopecephalus kochi, a taxon that has been proposed as synonymous with Pterodactylus, was analyzed but poor preservation  prevented adequate assumptions on niche specializations.”
This is a list of old news, old traditions and old excuses. Where is the original thinking? Where are the pithy insights?
“Our preliminary analyses suggest that, although the Solnhofen archipelago was a rich pterosaur site, these taxa were not in direct competition, separated either by functional
anatomy or time. More data on paleoneurology is still needed to better understand niche occupation by Pterodactylus.”
In other words, we have nothing new to say, but wanted to come to Australia to make a presentation.

References
Cardozo FG, Sobral G and Rodriques T 2019. Ecological niches among pterosaurs from the Solnhofen archipelago. Journal of Vertebrate Paleontology abstracts.

Geographic cladogram of pterosaurs

So many pterosaurs come from so few places.
And those places are spread around the world. So, here (Fig. 1) is the large pterosaur tree (LPT, 239 taxa) with color boxes surrounding Solnhofen, Chinese, North American, South American and other geographic areas where they are found.

Figure 1. LPT with pterosaurs colorized according to geography.

Figure 1. LPT with pterosaurs colorized according to geography.

As before,
the traditional clades ‘Pterodactyloidea’ and ‘Monofenestrata‘ become polyphyletic when traditionally omitted taxa are included. Here (Fig. 1) four clades achieve the pterodactyloid-grade by convergence. Other pterosaur workers (all PhDs) omit or refuse to include most of these taxa, leading to false positives for the tree topologies they recover. Moreover, none recognize, nor cite literature for, the validated outgroup members for the Pterosauria (Fig. 1) preferring to imagine pterosaurs arising from unidentified and/or invalidated archosaurs or archosauriforms. Here we get to peak beneath the curtain.


References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

What is Alcmonavis poeschli?

Rauhut, Tischlinger and Foth 2019 describe
a disarticulated right forelimb/wing of a ‘non-archaeopterygid avialan theropod’, they named Alcmonavis poeschli specimen SNSB-BSPG 2017 I 133. It is the 13th Solnhofen bird.

The authors report,
“it is a more derived avialan than Archaeopteryx,” which brings up a problem.

Currently there are more than a dozen Solnhofen birds
or pre-birds in the large reptile tree (LRT, 1471 taxa). Many workers, including Rauhut, Tischlinger and Foth, throw them into a taxonomic wastebasket of ‘Archaeopteryx.’ Other authors have shown that some are not congeneric with others and these were noted by Rauhut, et al.

By contrast,
the LRT separates all of Solnhofen birds specifically, and many generically, recovering several at the bases of various Early Cretaceous bird clades. The LRT, employing relatively few forelimb traits and none specific to theropods/birds, nests Alcmonavis with the BSP 1999 I50 specimen identified as Archaeopteryx bavarica (the Munich specimen, Fig. 1), nesting at the base of the Jeholornis clade alongside the #12 specimen (Fig. 1), which nests at the base of the sister clade, the Scansoriopterygidae. Evidently there were enough traits in the new specimen forelimb to do this. I wasn’t sure at first.

Figure 1. Alcmonavis to scale with its sister in the LRT, the Munich specimen.

Figure 1. Alcmonavis to scale with its sister in the LRT, the Munich specimen. The authors did not attempt a reconstruction.

Notably,
Alcmonavis is twice the size of the Munich specimen (Fig. 1). The authors write, “Here we report on a new paravian specimen from the Lower Tithonian Mörnsheim Formation, representing the second theropod specimen from this unit, which overlies the Altmühltal Formation. The new specimen represents the largest avialan theropod yet recorded from the Jurassic and provides further evidence on the forelimb anatomy and the origin of flapping flight in basal avialans.”

The authors note that Alcmonavis
was found in the formation immediately above the one that yielded the majority of Solnhofen birds, including the Munich specimen.

Regarding the numbers and names, the authors write, 
“We propose to retain the original numbering of specimens, even if one accepts the different generic assignments, in order to avoid confusion between the recent and older literature. Given the gradual assembly of the avialan body plan and the general similarity of the basalmost members of this clade, it might be justified to simply talk about ’urvogel specimens’ instead of using the generic name Archaeopteryx, to thus accommodate the taxonomic uncertainty. Accordingly, the specimen described here should be regarded as the 13th urvogel specimen from the Solnhofen Archipelago.” 

This is confirmation of a practice already in place.
In the LRT and here at ‘Heresies’, all specimens from the Solnhofen limestones have been called, ‘Solnhofen birds’ for several years now. This leaves room for some specimen to be renamed when more of them are added to phylogenetic analyses, as documented in the LRT. The term ‘urvogel’ goes back to the false assumption that one ‘ur’ was present, rather than the large radiation already documented in the LRT.

The authors lament many layers of difficulty
in comparing the forelimb of Alcmonavis to those of other Solnhofen birds based on size and exposure, various proportions and robust qualities. As mentioned earlier, the LRT had no such problems using DGS methods to extract comparative data. Summarizing, the authors state, “despite the overall similarity and very similar proportions, the new specimen shows numerous small differences from Archaeopteryx, precluding a referral to this taxon. It is furthermore clear that SNSB-BSPG 2017 I 133 also cannot be referred to Ostromia or to any other known theropod taxon.”

“The phylogenetic analysis resulted in more than 99,999 trees with a length of 2690 steps. The strict consensus is rather well resolved and includes monophyletic Maniraptora, Paraves and Avialae with equivalent taxonomic contents to other recent analyses.”

Unfortunately the authors include only one taxon for Archaeopteryx.
They nest Alcomonavis between Archaeopteryx and higher birds, oblivious to the effects of taxon exclusion on their tree topology. Little else needs to be said. Deleting/ omitting/ ignoring key taxa is inappropriate at this stage of our understanding of Solnhofen birds.

Here is yet another case
where more taxa would have helped the original authors, not more characters. Taxon exclusion continues to be the number one problem in paleontology, not just with Jurassic birds.

Contra the title of Rauhut et al. 2019,
the new taxon is indeed an archaeopterygid, despite its size.


References
Rauhut OWM, Tischlinger H and Foth C 2019. A non-archaeopterygid avialan theropod from the Late Jurassic of southern Germany. elifesciences.org 2019;8:e43789. DOI: https://doi.org/10.7554/eLife.43789

You heard it here first: No two Archaeopteryx look the same.

The science section
of the online British news outlet, the Guardian, reported on the 12th (Haarlem) specimen of Archaeopteryx re-named Ostromia. You can read that story online here.

From the Guardian article:
“Of the Twelve Specimens Once Known as Archaeopteryx (SPOKA), only nine continue to carry that name. At the end of the day, we can’t all be winners. But even within that group of nine specimens, no two Archaeopteryx look the same. Rauhut and colleagues report that there is significant variation in the size, shape, spacing and orientation of the teeth, as well as differences in body size between the different specimens. This could be an ontogenetic pattern, with larger individuals representing adults with more developed dentition. Alternatively, as the Solnhofen Basin constituted a tropical island archipelago during the Late Jurassic, these differences in body size and dentition could be interpreted as island adaptations. Similarly to today’s Galápagos finches, different populations of Archaeopteryx may have adapted to different insular environments.”

We looked at
Solnhofen birds (Fig. 1) earlier here and Ostromia here. Since 2015 readers have known that no two Archaeopteryx specimens were identical and that phylogenetic analysis split them apart to nest at the base of each one of all the Cretaceous bird clades. And yes, we know of an embryo archaeopterygid, the Liaoning embryo most closely related to the London specimen.

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

It really is time to
run these birds through analysis and either affirm, modify or invalidate the results of the large reptile tree. And it should be done by someone with firsthand access to all the specimens. That would be a good test.

References
Elzanowski, A., 2002. Archaeopterygidae (Upper Jurassic of Germany) In: Chiappe LM, Witmer LM, eds. Mesozoic Birds. Above the Heads of Dinosaurs. Berkeley: University of California Press. 129-159.
Foth C, Rauhut OWM. 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology 17:236

https://www.theguardian.com/science/2018/feb/21/the-new-specimen-forcing-a-radical-rethink-of-archaeopteryx

The 11th Archaeopteryx: closer to Sapeornis

Figure 1. The 11th specimen attributed to Archaeopteryx in situ. See figure 2 for a reconstruction. This specimen remains in private hands without a museum number.

Figure 1. The 11th specimen attributed to Archaeopteryx in situ. See figure 2 for a reconstruction. This specimen remains in private hands without a museum number. Note all the soft tissue feathers preserved here.

Archaeopteryx number 11
(Figs. 1, 2) has no museum number and is in private hands, but Foth et al. 2014 published a description in Nature. These authors unfortunately considered this specimen just another Archaeopteryx, but one well supplied with feather impressions. In the large reptile tree (LRT, subset Fig. 3) this Solnhofen bird nests at the base of the node that produced two specimens of Sapeornis, a clade convergent with Euronithes in having a pygostyle.  The 11th specimen is complete and articulated, but lacks a large part of the cranium.

Figure 2. Most of the complete Solnhofen birds, including Archaeopteryx and the eleventh specimen to scale.

Figure 2. Most of the complete Solnhofen birds, including Archaeopteryx and the eleventh specimen to scale.

Foth et al. 2014 do not mention
the lack of a sternum. Sapeornis likewise lacks a sternum even though more primitive taxa have one.

Figure 4. The eleventh Archaeopteryx nests with Sapeornis.

Figure 4. The eleventh Archaeopteryx nests with Sapeornis.

At first glance
this appears to be an ordinary Archaeopteryx. However, when you put the dividers on the bones you find that it differs in subtle ways from the holotype and is more similar to Sapeornis and its sisters. As I mentioned yesterday, it would be a good thing for all early bird workers to start considering the Solnhofen birds individual genera, not a single genus. It’s just a lazy habit we have to overcome.

References
Foth C, Tischlinger H and Rauhut OWM 2014. New specimen of Archaeopteryx provides insights into the evolution.of pennaceous feathers. Nature 511:79–83.DOI: 10.1038/nature13467

Solnhofen “Find a Twin” Contest

Readers,
I’ve looked at many dozen Solnhofen pterosaur specimens and haven’t yet found two that are identical.

If you can present me/us with two identical Rhamphorhynchus or Pterodactylus I will make the announcement. Send in pictures or museum numbers, please.

I haven’t compared every specimen to every other one yet, but I’m not sure we can find two identical specimens. There is an incredible variety out there.

The most likely scenario would be to find two conspecific pterosaurs on the same slab, but I don’t think there is such a thing yet discovered.