Outdated paleontology textbooks

Following in the wake of the fading paleo textbook I grew up with,
Vertebrate Paleontology (Carroll 1988), comes more recent editions from Professor Michael Benton (3rd edition 2005; 4th edition 2014, Fig. 1).

Figure 1. Vertebrate Paleontology by M. Benton.

Figure 1. Vertebrate Paleontology by M. Benton.

Prior reviews:
“The book is a main textbook for vertebrate palaeontology and aimed at students and anyone with an interest in the evolution of vertebrates. It meets its five aims and is excellent value.” 
(Proceedings of the Open University Geological Society, 1 April 2015)

From the Amazon.com website:
“This new edition reflects the international scope of vertebrate palaeontology, with a special focus on exciting new finds from China. A key aim is to explain the science. Gone are the days of guesswork. Young researchers use impressive new numerical and imaging methods to explore the tree of life, macroevolution, global change, and functional morphology.

“The fourth edition is completely revised. The cladistic framework is strengthened, and new functional and developmental spreads are added. Study aids include: key questions, research to be done, and recommendations of further reading and web sites.

“The book is designed for palaeontology courses in biology and geology departments. It is also aimed at enthusiasts who want to experience the flavour of how the research is done. The book is strongly phylogenetic, and this makes it a source of current data on vertebrate evolution.”

A review from the perspective of the large reptile tree
Unfortunately this volume invalidates itself by taxon exclusion at many nodes. Readers are better served at ReptileEvolution.com where taxa are included and tested, not just reported on.

Dr. Benton has been caught excluding taxa
in the past (e.g. Hone and Benton 2007, 2009Yang et al. 2018) to support his own outdated and invalidated hypotheses (like Scleromochlus, the bipedal croc with tiny hands as a sister to Bergamodactylus, the basal pterosaur with giant hands). His textbook presents several falsehoods about pterosaurs (e.g. open ventral pelvis, all were quadrupedal, origin from archosaurs). The first dichotomy splitting the Reptilia into Lepidosauromorpha and Archosauromorpha is not presented, leading to many mix-ups in derived taxa. Lacking is a wide gamut specimen-based phylogenetic analysis, like the large reptile tree, a modern requirement for every textbook on this subject in the present cladistic era. Rather, a number of smaller, more focused previously published studies are presented without review or criticism.

Finally,
because the Benton volume is a physical book, it cannot keep up with the weekly and daily additions of online competitors, like www.ReptileEvolution.com is able to do. The Benton book, and all such textbooks, start to become outdated the moment the authors submit their final drafts to the publishers, weeks or months before their publication dates. It’s just the nature of publishing. It cannot be avoided due to this time lag.

Popular books make similar mistakes
Naish and Barrett 2016 wrote a dinosaur book, “Informed by the latest scientific research.” Sadly, no. This book is a journalistic compendium of prior studies, many of which were invalidated by taxon exclusion. As in most traditional studies, bipedal crocs are ignored in their cladograms dealing with the origin of dinos. These authors also considered tiny bipedal Scleromochlus ancestral to pterosaurs + Dinosauromorpha (p. 34), following Benton 1999. This hypothesis of relationships was invalidated by Peters 2000 who simply added taxa ignored by 4 prior authors, including Benton 1999. We can also be disappointed that these PhD authors bought into the bogus Yi qi styliform reconstruction as a bat-winged bird amalgam without either a critical analysis or a second thought of this one-of-a-kind mistake. The authors also supported the debunked origin of birds from theropods of descending size (pp. 184–185). Authors and editors should have checked for logic errors like the following from Naish and Barrett: “The fact that a microraptor specimen preserves a fish in its belly, indicates that they were also spending time on the ground.”

Just let that sink in if you don’t get it right away.

Parker 2015
reports on traditional mishandlings of the evolution of reptiles considered and criticized here at ReptileEvolution.com and PterosaurHeresies. As is typical in traditional paleontology, too often sister taxa in Parker 2015 do not document a gradual accumulation of derived traits. For instance the first dichotomy in the Parker topology splits Synapsids from Sauropsids. So no amphibian-like reptiles are recognized. The next dichotomy splits Eureptilia from Anapsida / Parareptilia. So pareiasaurs nest with mesosaurs. Parker considers the origin of ichthyosaurs and turtles, “uncertain.” A wide gamut cladogram testing all possibilities has no such problem Parker splits the invalid clade Sauria into Lepidosauromorpha and Archosauromorpha, then splits Sauropterygia and Lepidosauria, then lumps Pterosauria and Dinosauria together in the invalid clade Avemetatarsalia / Ornithodira. And with Avemetatarsalia we once again return to Benton 1999, which keeps surviving like a zombie.

As others have noted,
the present day is a ‘Golden Age’ in paleontology where discoveries are being posted weekly if not daily. Paper textbooks just cannot keep up with the latest hypotheses of relationships when compared to online studies and critiques that can pop up within hours of academic publication.

Benton would not have written editions 1 and 2
unless Carroll 1988 had become obsolete. Benton would not have written editions 3 and 4 if he didn’t think the earlier editions were failing to keep with our understanding of paleontology. Given the time it takes to produce, publish and distribute giant textbooks, It may be time for textbooks to go extinct and evolve into current online information.

References
Benton MJ 2005. Vertebrate Paleontology 3rd Edition PDF online Wiley-Blackwell 455 pp.
Benton MJ 2014. Vertebrate Paleontology 4th Edition Wiley-Blackwell 480 pp.
Carroll RL 1988. Vertebrate Paleontology and Evolution. WH Freeman and Co. New York.
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. 
Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Naish D and Barrett P 2016. Dinosaurs. How they lived and evolved. Smithsonian Press.  online here.
Parker S (general editor) 2015. Evolution. The whole story. Firefly Books 576 pp.
Peters D 2000. A redescription of four prolacertiform genera and implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106: 293-336

 

Another disc-head anurognathid from Jurassic China

Yesterday Yang et al. 2018 presented NJU-57003 (Figs. 1–3), a small anurognathid pterosaur with a great deal of soft tissue preservation, including feather-like filaments, said to be homologous with feathers. That was shown to be invalid by taxon exclusion here.

Today we’ll reconstruct
the crushed skull using DGS and nest this specimen in a cladogram using phylogenetic analysis (Fig. 4) in a few hours. Yang et al. were unable or unwilling to do either, even with firsthand access to the fossil and nine co-authors.

Figure 1. The NJU-57003 specimen and outline drawing, both from Yang et al. 2018. Various membranes and the overlooked sternal complex are colored in here.

Figure 1. The NJU-57003 specimen and outline drawing, both from Yang et al. 2018. Various membranes and the overlooked sternal complex and prepubes are colored in here. Clearly the uropatagia are separated here, as in Sharovipteryx. No wing membrane attaches below the knee.

Overlooked by Yang et al.
the sternal complex is quite large beneath the wide-spread ribs, a trait common to anurognathids. The torso, like the skull, would have been much wider than deep in vivo.

Figure 2. The skull elements of NJU-57003 colored to help alleviate the chaos of the crushed specimen. See figure 3 for the same elements reconstructed.

Figure 2. The skull elements of NJU-57003 colored to help alleviate the chaos of the crushed specimen. I can’t imagine betting able to interpret this skull without segregating each piece with a different color. See figure 3 for the same elements reconstructed with these colors.

As in other disc/flathead anurognathids
the palatal processes of the maxilla (red in Figs. 2, 3) radiate across the light-weight palate.  Yang et al. mislabeled these struts the ‘palatine’ (Fig. 1) following in the error-filled footsteps of other pterosaur workers who did not put forth the effort to figure things out.

The skull
is likewise supported by relatively few and very narrow struts. Contra Yang et al. 2018, who once again, mistakenly identify the toothy maxilla as an scleral ring (Fig. 1), the actual scleral rings (Figs. 2, 3) are complete and smaller within a large squarish orbit bounded ventrally by a deep jugal.

Figure 3. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids.

Figure 3. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids. Note the eyes, as in ALL pterosaurs, are in the back half of the skull.

Discodactylus megasterna (Yang et al. 2018; Middle-Late Jurassic, Yanlio biota, 165-160mya; NJU-57003) is a complete skeleton of a disc-skull anurognathid with soft tissue related to Vesperopterylus. The sternal complex is quite large to match the wider than tall torso. Distinct from other anurognathids, m4.1 does not reach the elbow when folded.

Figure 4. Subset of the LPT nesting Discodactylus with Vesperopterylus within the Anurognathidae.

Figure 4. Subset of the LPT nesting Discodactylus with Vesperopterylus within the Anurognathidae.

This specimen was introduced without a name
in a paper that incorrectly linked pterosaur filaments to dinosaur feathers (Yang et al. 2018), rather than with their true ancestor/relatives, the filamentous fenestrasaurs, Sharovipteryx and Longisquama, taxa omitted in Yang et al. and all workers listed below. Details here. The authors were unable to score traits for the skull and did not mention Vesperopterylus in their text.

Apparently the same artist
who originally traced the skull of Jeholopterus in 2003 (Fig. 5) also traced the present specimen (Fig. 1) with the same level of disinterest and inaccuracy. Compare the original image (Fig. 5 left) to a DGS image (Fig. 5 right). 

Figure 5. The original 2003 tracing of Jeholopterus (upper left) was inaccurate, uninformed and uninformative despite first hand access compared to the more informative and informed tracing created using DGS methods.

Why did these anurognathids have such long filaments?
Owls use similar fluffy feathers to silence their passage through air, first discussed earlier here.

The pterosaur experts weigh in the-scientist.com/news:
“I would challenge nearly all their interpretations of the structures. They are not hairs at all, but structural fibers found inside the wings of pterosaurs, also known aktinofibrils,” says pterosaur researcher David Unwin at the University of Leicester in the UK who was not part of the study. “They discovered lots of hair-like structures, but [don’t report any] wing fibers. I find that problematic.” Unwin suspects these fibers are likely to be present but have been mislabeled as feathers.  

This is a very important discovery,” says Kevin Padian, a palaeontologist at the University of California, Berkeley, “because it shows that integumentary [skin] filaments evolved in both dinosaurs and pterosaurs. That’s not surprising because they are sister groups, but it is good to know.”  

Padian draws attention to the pycnofibers’ “hair-like structure” as illustrating that they served as insulation. This is yet another characteristic of dinosaur and pterosaurs, along with high growth rate, pointing to their common ancestor as warm blooded.  “I wish the illustrations in the paper were better, but there is no reason to doubt them,” he adds.

Dr. Padian knows better.
He’s keeping the family secret by not mentioning fenestrasaurs (Peters 2000).

“The thing that is cool is that it bolsters the idea that pterosaurs and dinosaurs are sister taxa, if they are correct in interpreting these structures as a type of feather,” writes paleobiologist David Martill of the University of Plymouth in the UK, in an email. 

Dr. Martill knows better.
He’s keeping the family secret by not mentioning fenestrasaurs.

The specimens described in the paper are very interesting, agrees Chris Bennett, a palaeontologist at Fort Hays State University in Kansas, but in an emailed comment he describes the interpretation of the structures as problematic. “The authors’ characterization of the integumentary structures as ‘feather-like’ is inappropriate and unfortunate,” he writes. Some of the structures look like they could be from fraying or other decomposition, rather than feathers. Bennett adds that filamentous structures for insulation and sensation are fairly common, from hairy spiders to caterpillars to furry moths. “It seems to me to be premature to use filamentous integumentary structures to support a close phylogenetic relationship between pterosaurs and dinosaurs,” says Bennett. 

Dr. Bennett knows better.
He’s keeping the family secret by not mentioning fenestrasaurs.

Benton stands by his conclusion that pterosaurs wore plumage. Asked about the suggestion that the feathers could be wing fibers, he writes in an email, “Actinofibrils occur only in the wing membranes, whereas the structures we describe occur sparsely on the wings, but primarily over the rest of the body.”

Dr. Benton knows better.
He’s keeping the family secret by not mentioning fenestrasaurs. More details here.

References
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoological Journal of the Linnean Society 118:261-308.
Hone DWE and Benton MJ 2007.
An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2009.
Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Peters D 2000. 
A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Yang et al. (8 co-authors) 2018. Pterosaur integumentary structures with complex feather-like branching. Nature ecology & evolution doi:10.1038/s41559-018-0728-7