I first heard this one at the 2nd Pterosaur Symposium in China.
Bennett (2012) reports that pterosaurs nested between the lumbering and aquatic archosauriforms Proterosuchus and Erythrosuchus. That moves the nesting away from Scleromochlus, Proterochampsids and Parasuchians, the previous archosaur ‘favorite candidates,’ which were earlier derided as “strange bedfellows.”
How is this possible?
Of course this ‘new’ nestinggives us no idea whatsoever as to the gradual accumulation of pterosaurian traits, which is one of the great benefits anywhere and everywhere along the large reptile tree. What do Erythrosuchus and Proterosuchus have to do with pterosaurs???
And everyone thinks that -I- delve into pseudoscience??
Where is the critical thinking here??
Well, to be fair…
I was able to nest pterosaurs with turtles and both nested with sauropterygiformes – but that was to prove a point made only in the absence of half of the Reptilia, the entire new Lepidosauromorpha (where turtles also nested). So anything is possible if you overlook or ignore certain taxa, like Huehuecuetzpalli, Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama.
Perhaps the title says it all
“The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined.” Bennett (2012) did not even consider other taxa promoted since his 1996 paper. “Did you even consider Sharovipteryx?” I asked him in China, “…the taxon that David Unwin briefly considered?” He shook his head. Then I shook my head in disbelief. This is truly putting the blinders on. For what possible reason?
Bennett (2012) did include Tanystropheus,
a taxon that was once mistakenly considered a pterosaur (the skeleton was jumbled and the elongated neck bones were mistaken for wing bones). So what happened here? Bennett (2012) did not mention how many extra steps a shift to Tanystropheus would take. Tanystropheus was scored with X or – for 39 out of 144 traits, despite being completely known.
Partitioning and Congruence
Importantly, Bennett (2012) divided his 1996 dataset into Cranial, Postcranial, Forelimb Hindlimb and Cursorial subsets to see what sort of tree each subset recovered. Loss or resolution plagued most of these subsets. In the large reptile tree there’s not much change when testing cranial vs post cranial characters, so long as you don’t include any headless specimens with the cranial subset.
Bennett (2012) did not test individual genera within Lepidosauromorpha, Rhynchosauria, Proterosuchidae, Erythrosuchidae, Proterochampsidae, Parasuchia, Ornithoduchidae, Suchia or Dinosauria, about half of his included taxa. Earlier we talked about the dangers involved in using such suprageneric taxa, especially when several of Bennett’s taxa are actually Lepidosauromorphs.
Bennett (2012) reports: pterosaurs share with basal archosauriforms: 1) presence of palatal teeth (I need to see these before I believe in them), 2) absence of antorbital fossa (Erythrosuchus has one, so does Proterosuchus, but just barely ) and 3) broad puboischiadic plate (medially oriented in Proterosuchus, divided in erythrosuchids). Later Bennett (2012) adds, “absence of cnemial crest.” So true! But this is a plesiomorphic trait.
Against Nesbitt (2011)
Bennett (2012) reflects my own thinking when he writes, “I reject such atomisation of morphology.”
Bennett on Leaping
Bennett (2012) reports, “However, in the quadrupedal pterosaurs the increased number of sacral vertebra increased the strength of the connection between the vertebral column and hindlimb so as to better transfer the dynamic forces associated with arboreal leaping primarily powered by the enlarged hindlimb, and associated with flapping of the hindlimb in flight… The long preacetabular process of the ilium in pterosaurs provided enlarged areas of origin and improved angles of pull for hindlimb muscles associated with arboreal leaping and flapping of the hindlimb in flight…” While some of this may be true (doubtful about flapping the hindlimbs), it ignores the long preacetabular process and increased sacrals in Cosesaurus and Sharovipteryx.
Bennett reported with regard to Hone and Benton (2007, 2008), “Hone kindly sent me their Nexus files, and comparing them with the published data sets of Bennett (1996) and Peters (2000) revealed that the inability of Hone and Benton (2007) to replicate the analysis of Bennett (1996) was not the result of differences in the coding of Scleromochlus for Char. 43, but rather was the result of (1) four separate coding errors in retyping the data matrix and (2) leaving eight of the 9s that Bennett (1996) used to code for missing data in the matrix unchanged while using ? as the symbol for missing data and then including 9 in the Symbols statement of the Nexus file so that PAUP treated 9 as a distinct character state rather than as missing data. Similarly, their inability to replicate Peters’ (2000) analysis of a modified Bennett (1996) data set was the result of seven coding errors in retyping Peters’ published data matrix plus two 9s treated as a distinct character state.” This comes as no surprise as many of Hone’s colleagues have expressed similar concerns with Hone’s work in private correspondence.
Ignoring Peters (2010) on Digitigrade Ptero Tracks
Bennett (2012) reports, “…trackway evidence shows them to have been plantigrade quadrupeds (Lockley et al. 1995; Bennett 1997b; Unwin 1997; Mazin et al. 2003) and the complete absence of trackways of basal pterosaurs…” I showed digitigrade tracks in 2010. Why not discuss them? Because Bennett swore he would ignore any papers I published after 2000 and so far he’s doing a pretty good job of keeping his word.
Bennett (2012) reported, “The homologies of the [distal] tarsals are uncertain.” This is only true in the context of an Archosauromorph relationship. Bennett (2012) reported, “but in no case is there any evidence that any of them is the centrale.” Here he ignored or dismissed Peters (2000) as I demonstrated the three distal tarsals are the centrale, dt3 and dt4 when pterosaurs descend from Macrocnemus and Cosesaurus.
Bennett (2012) reported, “Although the origin and homology of the pteroid is uncertain (Unwin et al. 1996).” This ignores Peters (2009) who showed that Cosesaurus had a pteroid and preaxial carpal.
Bennett (2012) recovered four trees with its weakest links between Prolacerta and Erythrosuchidae, the nodes which include Tanystropheus, the drepanosaurs and pterosaurs (the by default nested taxa), with the archosauromorph, Proterosuchus, in the middle. Few of these taxa look like their sisters. Many more taxa are needed to demonstrate gradual accumulations of traits.
Bennett (2012) “was benefited from conversations and/or correspondence with M.J. Benton, D.W.E. Hone, S. Nesbitt and J.J. Wiens. He thanks S. Brusatte, D.W.E. Hone, S. Nesbitt and P. Senter for kindly providing… Nexus files and pertinent information from their respective analyses. [He] thanks D. Naish for a constructive review.”
Of course I would have rejected the manuscript for being incomplete. This study does nothing to show us a gradual accumulation of pterosaurian traits. It ignores the findings of pertinent published works and generally makes paleontologists look bad on several levels. If anyone can defend such a paper, please do so! Tell me how pterosaurs are such good sisters for Erythrosuchus and Proterosuchus.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zool J Linn Soc. 118:261–309.
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Hone DWE, Benton MJ. 2007. An evaluation of the phylogenetic relationships of the pterosaurs among archosauromorph reptiles. J Syst Paleontol. 5:465–469.
Hone DWE, Benton MJ. 2008. Contrasting supertree and total-evidence methods: the origin of pterosaurs. In: Buffetaut E, Hone DWE, editors. Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Munich, Germany, p. 35–60, Zitteliana B 28.
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.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330.
Peters David 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification. Ichnos, 18: 2, 114 —141.