Restoring the tip of the Pteranodon rostrum in UALVP 24238

Another short one today.
Everyone in pterosaur land has wondered what shape and length the missing tip of the rostrum took on in the UALVP 24238 specimen of Pteranodon (improperly called ‘Dawndraco‘, Fig. 1). That’s because, unlike most other specimens, the upper and lower margins don’t converge to form a triangle in lateral view, but remain essentially parallel for most of their length.

Figure 1. The missing tip of the UALVP 24238 skull can be restored like the similar Tanking-David specimen skull tip. The dorsal rim is straight. The ventral rim is convex.

Figure 1. The missing tip of the UALVP 24238 skull can be restored like the similar Tanking-Davis specimen skull tip. The dorsal rim is straight. The ventral rim is convex.

The privately held
Tanking-Davis specimen of Pteranodon is the most similar to the UALVP 24238 rostrum. Yes, it converges, but at a very shallower angle. Anteriorly the ventral margin curves up to meet the very straight dorsal margin. The same can be imagined/restored for the missing UALVP 24238 rostrum, and the result appears to be reasonable.

Figure 2. The UALVP 24238 specimen of Pteranodon is largely complete and here the tip of the rostrum is restored like that of a related specimen.

Figure 2. The UALVP 24238 specimen of Pteranodon is largely complete and here the tip of the rostrum is restored like that of a related specimen.

As in most pterosaur genera,
no two specimens are identical. See the panoply of known relatively complete Pteranodon skulls to scale and in phylogenetic order here.

Advertisements

Was Mesosaurus fully aquatic?

A new paper by Demarco, Meneghel, Laurin and Piñeiro 2018
asks, Was Mesosaurus (Fig. 1) a fully aquatic reptile? The authors report, “Mesosaurs are widely thought to represent the earliest fully aquatic amniotes,” but conclude, “more mature individuals might hypothetically have spent time on land. In this study, we have found that the variation of the vertebral centrum length along the axial skeleton of Mesosaurus tenuidens fits better with a semi-aquatic morphometric pattern, as shown by comparisons with other extinct and extant taxa.”

Figure 1. Mesosaurus origins recovered by the LRT. The fossil record appears to be topsy turvy here with the basal taxa appearing 30 million years later. Fossils are rare and discovery is rarer. Things like this sometimes happen.

Figure 1. Mesosaurus origins recovered by the LRT. The fossil record appears to be topsy turvy here with the basal taxa appearing 30 million years later. Fossils are rare and discovery is rarer. Things like this sometimes happen. None of these taxa appear to be fully aquatic, but related thalatttosaurs and ichthyosaurs definitely were.

The authors report methods
“We measured the centrum length for each available vertebra in the mesosaur skeletons. All measurements were taken on digital images.” They also looked at Claudiosaurus and Thadeosaurus (Fig. 1), but did not conduct a phylogenetic analysis that included these and other closest sisters to Mesosaurus in the large reptile tree (LRT, 1263 taxa). For comparison, the authors looked at the unrelated vertebral profiles of Cotylorhynchus, Casea, Varanus and Varanops

All of the ancestors to Mesosaurus in the LRT
kept four functioning legs, so terrestrial locomotion remained within their abilities. That seems pretty clear. At Anarosaurus (Fig. 1) the Sauropterygia split off with Pachypleurosaurus and Diandongosaurus at the base. At Brazilosaurus the Thalattosauria + Ichthyosaurus split off with Wumengosaurus (Middle Triassic)  and Serpianosaurus (Middle Triassic) at the base. That means taxa from Galephyrus to Wumengosaurus had their genesis prior to the Early Permian, in the Late Carboniferous. That gives time enough for basal ichthyosaurs, like Grippia, to appear in the Early Triassic. This is a prediction that can be tested and confirmed with new discoveries in the Late Carboniferous.

Note that basal marine younginiform diapsids
are basal to the clade Enaliosauria, which includes mesosaurs, sauropterygians, thalattosaurs and ichthyosaurs in the LRT. Mesosaurs were not basal anapsids (contra Demarco et al. 2018 and all prior authors dealing with mesosaurs).

The authors report,
“The evidence suggests thatMesosaurus may have been slightly amphibious rather than strictly aquatic, at least when it attained a large size and an advanced ontogenetic age, though it is impossible to determine how much time was spent on land and what kind of activity was performed there. Thus, it is impossible to know if mesosaurids came onto land only to bask, like seals or crocodiles, or if they were a bit more agile.”

Since mesosaurs still had limbs, hands and feet,
we can imagine/surmise that they were able to crawl about on land. Based on their proximity to thalattosaurs and ichthyosaurs and the derivation from basal sauropterygians, they were aquatic as well.

It is noteworthy
that sauropterygians and ichthyosaurs experienced live birth. So, it is not surprising that mesosaurs, nesting between them, were also viviparous (Piñeiro et al. 2012).

Interesting
that mesosaurs despite their derived nesting, predate their late-surviving phylogenetic ancestors. This demonstrates the incompleteness of the fossil record and the likelihood of finding phylogenetic ancestors in earlier strata, which happens all the time

References
Demarco PN, Meneghel M,  Laurin M and Piñeiro G 2018. Was Mesosaurus a fully aquatic reptile? Frontiers in Ecology and Evolutiion 6:109. doi: 10.3389/fevo.2018.00109
Piñeiro G, Ferigolo J, Meneghel, M and  Laurin M 2012. The oldest known amniotic embryos suggest viviparity in mesosaurs. Historical Biology. 24 (6): 620–630. doi:10.1080/08912963.2012.662230

Juramaia: Jurassic placental or monotreme?

Luo et al. 2011
brought us Juramaia sinensis, hailed as a Middle Late Jurassic (164mya) eutherian mammal. They said Juramaia “extends the first appearance of the eutherian–placental clade by about 35Myr from the previous record.” 

Figure 2. Juramaia (Late Jurassic, 160 mya) is more completely known and nests between monotremes and therians (marsupials + placentals).

Figure 1. Juramaia (Late Jurassic, 160 mya) is nests between monotremes and therians (marsupials + placentals) on the monotreme side in the LRT. (Beijing Museum of Natural History BMNH PM1143).

By contrast
the large reptile tree (LRT, 1265 taxa) nest Juramaia at the base of the Prototheria (egg-laying mammals). Nesting at the base also means it is a monotreme sister to all Therian mammals, including the equally long-snouted and long-legged Ukhaatherium (late survivor in the Late Cretaceous; Novacek et al. 1997) at the base of all therians. Ukhaatherium is traditionally considered a member of the Asioryctidae, close to placentals, but with epipubic bones.

The emergence of placentals in the LRT
is estimated to have occurred in the Early to Middle Jurassic, based on the Late Jurassic appearance of Shenshou, Maopatagium, and Vilevolodon, highly derived members of the Glires nesting with rodents.

The basalmost placental in the LRT,
the extant Caluromys, still has a pouch. But remember, it’s not one trait or two that tells you what a taxon is, but where the taxon nests in the cladogram. That’s why we have amphibian-like reptiles, mammal-like reptiles and the former ‘amphibian’ Diadectes nesting as a derived millerettid in the LRT. Remember, earlier we noted that the marsupial open pouch was enlarged and co-opted to form a nursery, then a parachute in members of the Volitantia, another basal placental clade. So we expect to see some sort of pouch in basalmost Eutherians, so it carries over into Volitantia.

Figure 2. Subset of the LRT focusing on basal Mammalia and the nesting of Juramaia with prototheres, not placentals.

Figure 2. Subset of the LRT focusing on basal Mammalia and the nesting of Juramaia with prototheres, not placentals. Compare to Luo et al. in figure 3.

Let’s take a closer look at Juramaia.
Luo et al. report, “This mammal has scansorial forelimb features, and provides the ancestral condition for dental and other anatomical features of eutherians.”

  1. Juramaia has 5 premolars and 3 molars, typical for Cretaceous eutherians. AND also typical of Jurassic prototherians. Evidently these were not considered, some of which postdate 2011.
  2. A long list of dental traits that the LRT does not consider. These must be basal to all mammals but lost in extant prototheres.
  3. Competing cladograms, including one with dozens of tooth-shape traits. The LRT has relatively few of those, so scores are not weighted toward dentition, which tends to converge in unrelated taxa.
  4. Juramaia is more closely related to extant placentals than all metatherians of the Cretaceous including Sinodelphys and Deltatheridium. In the LRT Sinodelphys also nests as a protothere. Deltatheridium nests as an unrelated derived marsupial carnivore. Juramaia nests closer to placentals in the LRT, too, but not closer than the small, tail-hanging didelphids, like Caluromys.

Competing cladograms (Fig. 3)

  1. Both the Luo et al. and LRT cladograms use or can use the cynodont, Thrinaxodon, and a number of other cynodonts as basal taxa.
  2. Luo et al. nest Haldanodon and Castorocauda as mammals within Megazostrodon. The LRT does not.
  3. Luo et al. include several mandible-only taxa. The LRT has very few.
  4. About half of the taxa appear to conform between the two cladograms (Fig. 3) demonstrating how powerful convergent dental traits can be. As some higher mammals lose their Y- and W-cusp-shapes, their cusps and/or teeth and end up with simple rows of cusps or single cusps.
  5. The LRT has the advantage of employing taxa from the last seven years unavailable to Luo et al. 2011. It is worthwhile to note the long list of pertinent taxa known from more or less complete skeletons in the LRT not employed by Luo et al.
  6. In the Luo et al. cladogram, metatherians and eutherians both arise from a last common ancestor, Aegialodon (Early Cretaceous, known only from teeth). In the LRT, eutherians arise from mink-sized arboreal metatherians with exposed nipples and open pouches.
  7. In the Luo et al. cladogram Vincelestes is an egg-laying mammal with maxillae that contact each other dorsally. In the LRT this fanged predator nests with other fanged predators with maxilla that contact each other dorsally, like Thylacosmilus.
Figure 2. On the left, the Luo et al. 2011 cladogram, colorized here for clarity. On the right clade colors are applied to Luo et al. taxa according to their nesting in the LRT. Not much correspondence, except on more completely known taxa. The LRT only tests more completely known taxa. 

Figure 3. On the left, the Luo et al. 2011 cladogram, colorized here for clarity. On the right clade colors are applied to Luo et al. taxa according to their nesting in the LRT. Not much correspondence, except on more completely known taxa. The LRT only tests more completely known taxa.

References
Luo Z-X, Yuan C-X, Men Q-J and JiQ 2011. A Jurassic eutherian mammal and divergence of marsupials and placentals. Nature 476: 442–445. doi:10.1038/nature10291.

Novacek MJ, Rogier GW, Wible JR, McKenna MC, Dashzev g D and Horovitz I 1997. Epipubic bones in eutherian mammals from the Late Cretaceous of Mongolia Nature 389: 483-486.

wiki/Juramaia

wiki/Ukhaatherium

More evidence that euharamyidans are mislabeled Jurassic rodents

Figure 1. The Jurassic mammal Shenshou, which nests within Allotheria (Haramiyida + Mutituberculata) within the Mammalia, as I proposed based on the LRT without knowledge of this paper.

Figure 1. The Jurassic mammal Shenshou, which nests within Allotheria (Haramiyida + Mutituberculata) within the Mammalia, as I proposed based on the LRT without knowledge of this paper.

Euharamyidans include the squirrel-like Jurassic gliders
Shenshou (Figs. 1,2 ), Vilevolodon and Maiopatagium in the large reptile tree (LRT, 1265 taxa). These are sisters to the squirrel, Ratufa, the squirrel-like Paramys and two living rodents, Rattus and Mus (rat and mouse).

Mao et al. 2018 report, “The new evidence suggests presence of diphyodonty in euharamiyidans. While it will take time to amass data to resolve the discrepancy between competing phylogenetic hypotheses about ‘haramiyidans’, multituberculates, and/or allotherians, it is helpful to continue deepening our knowledge about the morphology of euharamiyidans. Our finding of potential diphyodonty in euharamiyidans provides an additional piece of evidence for mammalness of the peculiar group.”

Figure 2. Shenshou skull traced in colors.

Figure 2. Shenshou skull traced in colors.

Above:
The skull of Shenshou (Fig. 2), close to living squirrels. Evidently the molar cusps are convergent with those of Haramiyavia, but there are few other similarities.

Below:
Haramiyavia (Fig. 3), a pre-mammal cynodont with a small canine and large incisors not related to Shenshou. Note the dual articular/dentary jaw joint in Haramiyavia, missing (actually evolved into ear bones) in Shenshou. Such a jaw joint marks this taxon as a pre-mammal synapsid.

Figure 1. Haramiyavia reconstructed and restored. Missing parts are ghosted. Three slightly different originals are used for the base here. The last appears to be the least manipulated and it appears to fit the premaxilla better.  The fourth maxillary tooth appears to be a small canine. The groove on the dorsal premaxillary appears to be for the nasal, not the septomaxilla. Parts are taken from both mandibles

Figure 3. Haramiyavia reconstructed and restored. Missing parts are ghosted. Three slightly different originals are used for the base here. The last appears to be the least manipulated and it appears to fit the premaxilla better.  The fourth maxillary tooth appears to be a small canine. The groove on the dorsal premaxillary appears to be for the nasal, not the septomaxilla. Parts are taken from both mandibles

In the LRT, Haramyavia, a basal member of the Haramiyida
nests with other pre-mammals like Brasiliodon and Sinoconodon, hence: not related to euharamiyidans. Determining the clade based on traits (no matter what these traits may be) is the cause of the phylogenetic confusion based on tooth shape and replacement patterns, which can converge. Only a taxon’s placement on a cladogram can tell you what an animal really is. Sadly, that’s a current heresy, not widely appreciated.

According to Wikipedia
(ref below): Haramiyidans are a long lived lineage of mammaliaform cynodonts. Their teeth, which are by far the most common remains, resemble those of the multituberculates. However, based on Haramiyavia, the jaw is less derived; and at the level of evolution of earlier basal mammals like Morganucodon and Kuehneotherium, with a groove for ear ossicles on the dentary.[1] They are the longest lived mammalian clade of all time.”

As the LRT showed several years ago
the rodent-like Euharamiyidans (Fig. 1) nest with placental rodents in the clade Glires, not with the much more primitive pre-mammals like Haramiyavia (Fig. 3).

Mao et al. 2018 report, “presence of the diphyodont dentition alone is not diagnostic for mammals. This is because a diphyodont dentition exists not only in mammals but also in stem mammaliaforms, such as Morganucodon and docodonts, although there may be more than one replacement for the upper canine of Haldanodon (Martin et al., 2010b).”

By contrast, in the LRT
Morganucodon is a basal metatherian, not a stem mammaliaform. Which is one more reason why it has diphyodont dentition (milk teeth + permanent teeth). The late-surviving docodonts, Haldanodon and Castorocauda nest between the synapsids, Probainognathus and Pachygenelus in the LRT. Those four should be replacing all their teeth all the time. All four had a dual jaw joint that was not quite mammalian, but getting there!

Diphyodont dentition alone is diagnostic for mammals
because it implies toothless, milk-lapping/sucking hatchlings, (but be careful not to pull a Larry Martin here, because the LRT uses 231 traits and diphyodont dentition is not among them).

Among mammals
Mao et al. 2018 report, “tooth replacement is also complex among mammals. For instance, the molariform teeth of eutriconodonts show replacement and some species have the entire dentition replaced and show at least three tooth generations. Cheek tooth replacement is uncertain in “symmetrodontans”. In North American spalacotheriids deciduous canine and premolars were retained late in life and may never have been replaced; thus, their dentitions perhaps were monophyodont. This has been supported by the spalacolestine Lactodon from the Early Cretaceous Jehol Biota, in which there is no sign of cheek tooth replacement even though this taxon possesses deciduous-like antemolars. New CT scan data (unpublished) further confirmed that there is no tooth germ at any tooth locus, including incisors and canines, of Lactodon [= Lactodens”?]. Thus, presence of the diphyodonty in euharamiyidans, does not constitute a sufficient evidence for the group’s mammalian affinity.”

Let’s examine those arguments
in new light shed by the LRT.

  1. Eutriconodonts (Spinolestes, Gobiconodon and kin): These taxa do not nest within Mammalia in the LRT (contra Martin et al. 2015).
  2. Symmetrodontans (Zhangheotherium and kin): Zhangheotherium is a basal pangolin, hence the atavistic teeth, as in another placental clade, the archaeocete ‘whales’.
  3. Spalacotherids (Lactodon = Lactodens): Taxa like Lactodens nest within the prototheria in the LRT.

It always comes back down to phylogenetic analysis.
And the LRT answesr all such problems within its ken. The radiation of placental mammals was in the Early Jurassic based on the appearance of derived placental mammals in the Late Jurassic. Non-mammalian synapsids survived into the Middle Jurassic, so there was plenty of overlap.

Figure 4. Lactodens in situ. This Early Cretaceous protothere has tooth-lined jaws. At 72 dpi this is about 3x larger than life size.

Figure 4. Lactodens in situ. This Early Cretaceous protothere has tooth-lined jaws. At 72 dpi this is about 3x larger than life size.

PS. If you’re wondering about
Lactodens (= Lactodon; Fig. 4; Han and Meng 2018; Early Cretaceous) here it nests at the base of the echidna + platypus clade, two toothless (as adults) taxa. Perhaps that’s why the diphyodont dental rules start breaking down with this taxon, as described by Mao et al.

References
Mao F-Y et al. (5 co-authors) 2018. Evidence of diphyodonty and heterochrony for dental development in euharamiyidan mammals from Jurassic Yanliao Biota. Vertebrata PalAsiatica DOI: 10.19615/j.cnki.1000-3118.180803

https://en.wikipedia.org/wiki/Haramiyida

Wachtlerosaurus: a thalattosaur, not an archosaur

Perner 2018
introduces Wachtlerosaurus ladinicus (Fig. 1, 2), a tiny disarticulated reptile from the Middle Triassic Dolomites of northern Italy. Perner considers the specimen an archosaur. In the large reptile tree (LRT, 1264 taxa) the specimen nests with thalattosaurs and Thalattosaurus in particular. The purported antorbital fenestra is the naris.

Figure 1. From Perner 2018, the original reconstruction of Wachtlerosaurus. Scale bar added.

Figure 1. From Perner 2018, the original reconstruction of Wachtlerosaurus. Scale bar added. Note the elongate ribs considered parts of the pelvis here. Pes of Euparkeria added by Perner. Manus appears to be from a coelophysoid theropod and flipped left to right.

The Dolomites are about 250 million years old
and are formed from coral reefs in the Tethys Sea, a perfect niche for a marine reptile like a thalattosaur.

Figure 1. Wachtlerosaurus in situ and reconstructed in lateral view.

Figure 2. Wachtlerosaurus in situ and reconstructed in lateral view.

A reconstruction of the skull helps
(Fig. 1) put the pieces of the broken skull back together again.

A few other new interpretations on the paper.

  1. Perner 2018 identifies two long, parallel dorsal ribs surrounding a jumble of ?vertebrae as parts of an oversized pelvis (Fig. 1).
  2. Perner employs the humerus in place of a scapula (Fig. 1).
  3. Probably this scattered bone specimen is incomplete, not nearly complete, as described.
Figure 3. Subset of the LRT nesting Wachtlerosaurus with Thalattosaurus.

Figure 3. Subset of the LRT nesting Wachtlerosaurus with Thalattosaurus.

References
Perner T 2018. A new interesting archosaur from the Ladinian (Middle Triassic) of the Dolomites (Northern Italy) Preliminary report. Pp 1–8 in Some new and exciting Triassic Archosauria from the Dolomites (Northern Italy). Perner T and Wachtler M eds. Dolomythos-Museum, Oregon Institute of Geological Research.

New Triassic basal dimorphodontid: Caelestiventus

Britt, et al. 2018
bring us a new desert-dwelling Triassic pterosaur, Caelestiventus hanseni (Figs. 1, 2; BYU 20707, Museum of Paleontology at Brigham Young University) from western North America. They nest it with Dimorphodon (Fig. 1), from the English Jurassic, although Preondactylus (Fig. 3) is also similar, with a huge naris, and also from the Late Triassic. Caelestiventus is larger than most Triassic pterosaurs, with a wingspan of at least 1.5 meters. Coeval Raeticodactylus is similar in size and also fills in the lower orbit with a thin sheet of bone.

Britt, et al. also confirm the nesting
of ‘Dimorphodon’ weintraubi with anurognathids, something first published by Peters 2011 and reported here the same year.

Unfortunately
Britt and colleagues nest anurognathids as the sister taxa to Dorygnathus due to taxon exclusion. In the large pterosaur tree (LPT, 234 taxa) anurognathids nest with and arise from dimorphodontids. Among the many taxa missing from the Britt et al. tree is the IVPP giant embryo anurognathid, a completely preserved specimen, and Mesadactylus, another Jurassic transitional sister basal to anurognathids… also from North America.

Figure 1. Triasic Caelestiventus skull compared to Jurassic Dimorphodon. Readers, don't do the easy thing and go to the Wellnhofer diagrams for your pterosaur skulls. Use real data.

Figure 1. Triasic Caelestiventus skull compared to Jurassic Dimorphodon. Readers, don’t do the easy thing and go to the Wellnhofer diagrams for your pterosaur skulls. Use real data.

It’s always wonderful to see a new pterosaur taxon.
Congratulations to all coauthors on this paper.

Figure 4. The skull of Bergamodactylus (MPUM 6009)

Figure 2. The skull of Bergamodactylus (MPUM 6009) the most primitive pterosaur in the LPT.  No antorbital fossa here and not tested by Britt et al.

The sculptor of the skull
(Fig. 1) put a ‘Roman nose’ on the restoration of Caelestiventus. That illustration will float around the paleo-universe forever. However, I take my cue from the Triassc age of the specimen and the downturned dentary, as in the Triassic basalmost pterosaur, Bergamodactylus (Fig. 2), which has an unexpanded naris, to create a more transitional naris (Fig. 1), and from Preondactylus (Fig. 3), a closer relative with a large, yet straight naris, rather than create a derived version with more of a curve than Dimorphodon had.

Figure 3. Preondactylus from the Late Triassic is basal to Dimorphodon in the LPT.

The staff or hired artist
charged with illustrating Caelestiventus in vivo (Fig. 4) made a few mistakes. These were generated, no doubt, by the many false paradigms floating around out there. Here they are shown and corrected. (Just found out the artist is Michael Skrepnick, Dinosaursinart.com)​

  1. The manual claws should point down toward the palm, as in most tetrapods
  2. Pedal digit 5 should be on the lateral side of a much larger foot and it should not be involved in the uropatagia.
  3. The tail should be shorter if closer to Dimorphodon than to Preondactylus. Otherwise it might be that long.
  4. The rostrum is straight inLate Triassic sister, Preondactylus, so  perhaps a straight angled rostrum is more appropriate here.
  5. The wing membranes were stretched between elbow and wing tip, as all soft tissue pterosaur fossils demonstrate.
  6. The cranium probably tipped down posteriorly, as all related taxa demonstrate (Figs. 1–3).
Figure 2. Pity the poor staff artist trying to get a pterosaur correct in today's climate. Here the original and revised morphologies are presented.

Figure 4. Pity the poor staff artist trying to get a pterosaur correct in today’s climate. Here the original and revised morphologies are presented. Digit 5 need to go to the outside of a large foot and the tail is short.

Perhaps hoping to support the invalid archosaur origin of pterosaurs hypothesis,
Britt et al report the margin of an antorbital fenestra bears a remnant of a fossa. We looked at a similar interpretation earlier when Nesbitt and Hone 2010 attempted to pull a Larry Martin with that single trait from Dimorphodon. Thankfully, Britt et al. did not attempt to use Euparkeria or any phytosaurs for outgroups. But, regrettably, they didn’t use Cosesaurus either (Fig. 5). Avoiding further controversy, they left the basalmost node generic: “Pterosauria”.

Addendum: checking the SuppMat .nex file,
I see they employed the tritiosaur lepidosaur, Macrocnemus, and two large archosauriforms, Postosuchus and Herrerrasaurus for outgroup taxa. That still does not get you very far based on the verified and validated taxa listed below. Neither Postosuchus nor Herrerasaurus are related to Macrocnemus and pterosaurs.

Figure 5. Basal pterosaurs in the LPT.

Figure 5. Basal pterosaurs and their outgroups in the LPT.

Late addendum
Adding Caelestiventus to the LPT nests it basal to the Dimorphodon clade, not with Dimorphodon.

Figure 1. Maxilla, nasal and jugal of Caeletiventus, plus full mandible.

Figure 1. Maxilla, nasal and jugal of Caeletiventus, plus full mandible casts created by CT scans. Colors added here.

References
Britt BB, Dalla Vecchia FM, Chure DJ, Engelmann GF, Whiting MF, and Scheetz RD 2018. Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years. Nature Ecology & Evolutiondoi:10.1038/s41559-018-0627-y.
Nesbitt SJ and Hone DWE 2010. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605

https://en.wikipedia.org/wiki/Caelestiventus

Flugsaurier 2018: Pterosaur crest and pelvis news – you heard it here first

Flugsaurier 2018 part 6
Since the purpose of the symposium is increase understanding of pterosaurs, I hope this small contribution helps.

Cheng, Jiang, Wang and Kellner 2018
concluded: “The size of pelvic channel and the presence and absence of premaxillary crest may not be used for distinguishing the gender of wukongopterid pterosaurs.”

That’s confirmation
of an earlier finding first discussed here. and basically throughout the seven-year course of this blogpost. Click here for Pteranodon crest phylogenetic variation. Here for Darwinopterus.

References
Cheng X, Jiang S-X, Wang X-L and Kellner AWA 2018. The wukongopterid cranial crests and pelves: sexual dimorphism or not? Flugsaurier 2018: the 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 33–34.