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

 

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Pterosaur pycnofibres revisited: Yang et al. 2018

Yang et al. 2018 bring us a closer look
at pterosaur integumentary structures (= pycnofibres, pycnofibers) courtesy of Tom Kaye and his fluorescence technique,

From the abstract
These findings could imply that feathers had deep evolutionary origins in ancestral archosaurs, or that these structures arose independently in pterosaurs.”

The latter is true and has been known for years. 
Filament structures arose in the lepidosaur fenestrasaur ancestors of pterosaurs, including Cosesaurus, Sharovipteryx (Fig. 1) and Longisquama (Fig. 2). None of these are archosaurs. The archosaur hypothesis for pterosaur origins has failed to produce even one taxon with pterosaur synapomorphies that is not trumped by taxa first specified in Peters 2000 or more recently improved in the large reptile tree at ReptileEvolution.com, which includes pterosaur ancestors extending back to basal lepidosaurs, basal reptiles and Devonian tetrapods.

The problem is co-author Professor Michael Benton
doesn’t want pterosaurs to be derived from fenestrasaurs. The Yang et al. paper insisted that pterosaurs are archosaurs and members of the invalid Benton invented clade, Avemetatarsalia.

You might remember,
Professor Benton and Professor David Hone wrote a two-part set of papers (Hone and Benton 2007, 2009) that declared they would test two competing hypotheses of pterosaur origins Peters 2000 (fenestrasaurs) vs. Bennett 1996 (archosaurs). The second paper (2009) dropped all references to Peters 2000, deleting the taxa therein and falsely ascribed the now gutted hypothesis to Bennett 1996. Ultimately they were unable to find any ancestors for pterosaurs. That’s because they omitted them on purpose.

Figure 1. Sharovipteryx cervicals surrounded by filaments.

Figure 1. Sharovipteryx cervicals surrounded by filaments.

Why?
Benton (1999) declared tiny-fingered Scleromochlus was the nonviolent sister to pterosaurs and evidently Benton wanted to maintain that charade. That’s where he erected the invalid clade, Avemetatarsalia, which makes several appearances in Yang et al. 2018. Peters 2000 is not cited in Yang et al. 2018.

Longisquama in situ. See if you can find the sternal complex, scapula and coracoid before looking at figure 2 where they are highlighted.

Figure 2. Longisquama in situ. The bones are hard to see here due to filaments and skin, especially visible in the throat area. 

True to S. Christopher Bennett’s curse,
“You will not get published and if you do get published you won’t be cited.” And that’s why I publish here, online, where I can respond immediately when something gets published that includes taxon exclusion. This is the dark underbelly of paleontology. Sorry that I had to show you this.

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 complefeather-like branching. Nature ecology & evolution

Heretical origin and evolution of moles and shrew-moles

The traditional clade Insectivora
is a now-abandoned clade because its former members have been shown to be polyphyletic. Both shrews and moles are traditional members.

Unfortunately,
a remnant order, Eulipotyphla, still includes both shrews and moles. The large reptile tree (LRT, 1360 taxa, subset Fig. 4) nests moles, like Talpa, within Carnivora, derived from the mongoose, Herpestes, and the traditional canid ancestor, Prohesperocyon. All these taxa (Fig. 1) have transverse premaxillae and long, sharp canines. Talpa and Prohesperocyon both have a bulbous occiput, gracile zygomatic arch and elongate rostrum.

Figure 1. Taxa in the origin and evolution of moles, Herpestes, Prohesperocyon and Talpa.

Figure 1. Taxa in the origin and evolution of moles, Herpestes, Prohesperocyon and Talpa.

Uropsilinae is the clade of shrew-moles
Wikipedia reports, “The shrew moles (Uropsilus) are shrew-like members of the mole family of mammals. They share a full zygomatic arch with all other moles, while this arch is completely absent in shrews.” Notice how this author just ‘pulled a Larry Martin‘? A complete arch is a plesiomorphic (basal) trait. That means it is plesiomorphic for shrews, too. Some shrews, like Rhyncholestes (Fig. 3), retain a complete arch.

Figure 2. The mole-shrew, Uropsilus, is not related to the mole, Talpa (Carnivora), but is related to the shrew (clade Glires).

Figure 2. The shrew-mole, Uropsilus, is not related to the mole, Talpa (Carnivora), but is related to the shrew (clade Glires). Note the long premaxilla, large incisors, tiny canine (orange), arched jugal arch. Image from Hoffmann 1984. Despite the overall similarity of this skull to that of Talpa, note the differences in the dentition and various skull bone proportions, all scored for the LRT.

Uropsilus (Milne-Edwards 1871)
is a shrew-mole (Fig. 2) was described by Hoffmann 1984: “These small insectivores are shrew-like in external appearance, but exhibit a mole0like skull and dentition. The tail is long and forefeet are not enlarged, while the zyogmatic arch is complete, and the tympanic bones form an auditory bulla. Thus, this “shrew-mole” lacks skeletal specializations for digging found in more derived moles, and the derived characters of skull and dentition found in shrews.” Not sure what Hoffman was smoking here, but Uropsilus has a shrew skull (Fig. 2) and readily nests with shrews, like the formerly traditional marsupial, Rhyncholestes, in the LRT, apart from moles.

Figure 1. Skull of Rhyncholestes along with in vivo photo.

Figure 3. Skull of Rhyncholestes along with in vivo photo. This is the long-nosed shrew-opossum and its skull. This taxon is a sister to Uropsilus, but has a longer snout and more incisors. It does not nest with marsupials in the LRT.

Backstories for today’s players:
Herpestes ichneumon (Linneaus 1758; extant; 48-60cm in length) is the Egyptian mongoose. 9-10 teeth (x4) line the jaws with large carnassials. Derived from a sister to ProtictisHerpestes is a lower, shorter-legged ancestor to Procyon (above) with a relatively shorter rostrum.

Prohesperocyon wilsoni (Wang 1994; Late Eocene, 36 mya) was considered the earliest canid, but here nests between Herpestes, the mongoose, and Talpa the mole. Note the long, pointed skull, expanded occipital and reduced jugal and squamosal. These traits are further emphasized in Talpa (below).

Talpa europaea (Linnaeus 1758, extant) is the extant mole, a small burrowing mammal derived from Herpestes and Prohesperocyon. The large hand, enlarged with a finger-like centralia that extends like a pteroid along the medial axis, is anchored by huge muscles that arise from the anteriorly displaced scapula. The pelvic girdle is fused to an elongate sacrum. The premaxilla is transverse in Talpa and those are large canines.

Uropsilus scoricipes (Milne-Edwards 1871; Hoffmann 1984) is the extant shrew-mole, long considered the link between shrews and moles. Here Uropsilus nests with shrews, apart from moles. Note the tiny canines, deep premaxilla and arched jugal.

Rhyncholestes raphanurus (Osgood, 1924; long-nosed shrew-opossum, Chilean shrew opossum, extant; snout-vent length 20cm), nests in the LRT with another shrew with a complete zygomatic arch, Uropsilus. Wikipedia and other sources consider this shrew-like South American mammal a marsupial, but Wiki also notes that Rhyncholestes lacks a marsupium (pouch). Females have seven nipples. We looked at Rhyncholestes earlier here.

Figure 3. Subset of the LRT focusing on Carnivora, the basalmost eutherian clade. Talpa is the European mole. Shrews and shrew-moles nest within the clade Glires.

Figure 4. Subset of the LRT focusing on Carnivora, the basalmost eutherian clade. Talpa is the European mole. Shrews and shrew-moles nest within the clade Glires in the LRT.

Lots of “low hanging fruit” here…
Someone (= lots of biologists/paleontologists) left these mistakes for others (= yours truly) to repair. Should have been done ages ago. Taxon inclusion is once again the solution to traditional taxon exclusion problems.

References
Hoffmann RS 1984. A review of the shrew-moles (genus Uropsilus) of China and Burma. Journal of the Mammalian Society, Japan 10(2):69–80.
Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Milne-Edwards  H 1871.
 Descriptions of new species, in footnotes, pp. 92-93 In David, A., Journal d’un voyage en Mongolia et en Chine fait en 1866-68. Nouv. Arch. Mus. d’Hist. Nat. Paris, 7 (Bull.): 75–100.
Osgood WH 1924. Field Mus. Nat. Hist. Publ., Zool. Ser. 14:170.
Wang X 1994. Phylogenetic systematics of the Hesperocyoninae. Bulletin of the American Museum of Natural History. 221: 1–207.

wiki/Uropsilus
wiki/Talpa
wiki/Herpestes
wiki/Prohesperocyon

Origin of rodents and lagomorphs paper omits key taxa

From the Wu et al. 2012 abstract:

“The timing of the origin and diversification of rodents remains controversial, due to conflicting results from molecular clocks and paleontological data. The fossil record tends to support an early Cenozoic origin of crown-group rodents. In contrast, most molecular studies place the origin and initial diversification of crown-Rodentia deep in the Cretaceous, although some molecular analyses have recovered estimated divergence times that are more compatible with the fossil record. Here we attempt to resolve this conflict by carrying out a molecular clock investigation based on a nine-gene sequence dataset and a novel set of seven fossil constraints, including two new rodent records (the earliest known representatives of Cardiocraniinae and Dipodinae). Our results indicate that rodents originated around 61.7–62.4 Ma, shortly after the Cretaceous/ Paleogene (K/Pg) boundary, and diversified at the intraordinal level around 57.7–58.9 Ma.”

The Wu et al. cladogram
correctly derives placentals from marsupials, but employs Monodelphis as the outgroup rather than the Caluromys, as recovered by the large reptile tree (LRT, 1360 taxa, subset Fig. 1). The Wu et al. cladogram incorrectly nests horses with carnivores in the invalid clade, Laurasiatheria. The next split produces the clade Primates + Glires, omitting the clade Volitantia. Within the clade Glires, only two extant lagomorphs are employed, omitting 16 tree shrews, false tenrecs and many fossil taxa that preceded them as recovered by the LRT. Within the clade Rodentia, the large extant clades within the Wu et al. study matched the LRT, but the Wu et al. study omitted all fossil taxa, including plesiadapiformes, multituberculates, carpolestids and the extant aye-aye (Daubentonia).

Contra Li et al. 1987 and Wu et al. 2012,
rodents and rabbits diversified in the Early Jurassic, as we learned earlier, because their ancestors, the multituberculates and Henkelotherium (related to living pikas, Fig. 1), appear in the Middle and Late Jurassic. DNA does not work in deep time studies.

Figure 4. Mesozoic euthrerians (placentals, in black). Later taxa in light gray. All taxa more primitive than Mesozoic taxa were likely also present in the Jurassic and Cretaceous. None appear after Onychodectes. Madagascar separated from Africa 165-135 mya, deep into the Cretaceous with a population of tenrecs attached. No rafting was necessary. 

Figure 4. Mesozoic euthrerians (placentals, in black). Later taxa in light gray. All taxa more primitive than Mesozoic taxa were likely also present in the Jurassic and Cretaceous. None appear after Onychodectes. Madagascar separated from Africa 165-135 mya, deep into the Cretaceous with a population of tenrecs attached. No rafting was necessary.

References
Li C-K., Wilson RW, Dawson MR, Krishtalka L 1987. The Origin of Rodents and Lagomorphs. In: Genoways H.H. (eds) Current Mammalogy. Springer, Boston, MA
Wu S et al. (8 co-authors) 2012. Molecular and Paleontological Evidence for a Post-Cretaceous Origin of Rodents. PLoS ONE 7(10): e46445. https://doi.org/10.1371/journal.pone.0046445

The Creodonta revisited in the LRT

Keep in mind the concept of convergence
whenever reviewing purported members of the Creodonta. Several purported creodonts have been added to the large reptile tree (LRT, 1342 taxa) recently.

According to Wikipedia,
“Creodonts were the dominant carnivorous mammals from 55 to 35 million years ago, peaking in diversity and prevalence during the Eocene.”

McKenna1975 considered the Creodonta
the sister taxa to the Carnivora within the clade Ferae (Carnivora + Pholidota (= pangolins)). The LRT finds pretty much the same relationship, but with creodonts on the marsupial side of the node and carnivores on the placental side of the node. The arboreal didelphid Caluromys is the only taxon that nests between marsupial creodonts and placental carnivores at present. (In the LRT pangolins nest with currently dissimilar bats. Ancestors of both, Chriacus and Zhangheotherium were much more similar.)

Halliday et al. 2015 nested creodonts
as sisters to pangolins in a cladogram that bore little to no resemblance to the LRT.

Figure 1. Oxyaena, a traditional creodont. This is a cat-like member of the carnivorous Marsupialia.

Figure 1. Oxyaena, a traditional creodont. This is a cat-like member of the carnivorous Marsupialia.

According to Wikipedia
“Creodonta
 was coined by Edward Drinker Cope in 1875. Cope included the oxyaenids and the viverravid Didymictis but omitted the hyaenodontids. In 1880. he expanded the term to include MiacidaeArctocyonidaeLeptictidae (now Pseudorhyncocyonidae), OxyaenidaeAmbloctonidae and Mesonychidae. Cope originally placed creodonts within the Insectivora. In 1884, however, he regarded them as a basal group from which both carnivorans and insectivorans arose. Hyaenodontidae was not included among the creodonts until 1909. Over time, various groups were removed, and by 1969 it contained, as it does today, only the oxyaenids and the hyaenodontids.”

Figure 1. Hyaenodon horrid us was the size of a large dog. This carnivorous marsupial was formerly considered a creodont.

Figure 2. Hyaenodon horridus was the size of a large dog. This carnivorous marsupial is considered a traditional creodont.

The LRT recovers
members of the traditional Creodonta in the carnivorous clade of the Marsupialia (Fig. 3). Earlier we looked at similar situation with members of the Didelphidae.

Figure 1. Subset of the LRT focusing on Basal Mammalia including Creodonta.

Figure 3. Subset of the LRT focusing on Basal Mammalia including Creodonta. Members of the Didelphidae and Creodonta are sprinkled throughout this subset.

Here (Fig. 3) the traditional creodont Sinopa (Fig. 4) nests with the extant dasyurids, Dasyurus and Sarcophilus (Fig. 4).

Figure 1. Adding Sinopa to the LRT nests it here, between the extant quoll (Dasyurus) and the extant Tasmanian devil (Sarcophilus).

Figure 4. Adding Sinopa to the LRT nests it here, between the extant quoll (Dasyurus) and the extant Tasmanian devil (Sarcophilus).

References
Andrews CW 1906. Descriptive Catalogue of the Tertiary Vertebrata of the Fayum, British Museum.
Cope ED 1880. On the Genera of the Creodonta. Proceedings of the American Philosophical Society. 19(107): 76–82.
Halliday TJD, Upchurch P and Goswami A 2015. Resolving the relationships of Paleocene placental mammals. Biological Reviews: n/a–n/a. doi:10.1111/brv.12242. ISSN 1464-7931.
Matthew WD 1901. Additional Observations on the Creodonta.  Bulletin of the American Museum 14:1.
McKenna MC 1975. Toward a phylogenetic classification of the Mammalia. Pp. 21–46 in Luckett WP and Szalay FS. Phylogeny of the Primates. New York: Plenum.
Morlo M, Gunnell G and Polly PD 2009. What, if not nothing, is a creodont? Phylogeny and classification of Hyaenodontida and other former creodonts. Journal of Vertebrate Paleontology 29(Supplement 3): 152A.
Polly PD 1994. What, if anything, is a creodont?. Journal of Vertebrate Paleontology. 14: 42A.
Sinclair WJ 1905. The Marsupial Fauna of the Santa Cruz Beds, Proceedings of the American Philosophical Society 49:73.
Wortman JL 1901-1902. Eocene Mammalia in the Peabody Museum, pt. i. Carnivora,” American Journal of Science 11–14.

Encyclopædia_Britannica/Creodonta
wiki/Creodonta

Oreopithecus, a European ape at the center of yet another bipedal debate

During the Miocene (9–7mya)
the Italian peninsula, then reduced to a series of islands, was the jungle home to long-limbed apes like Oreopithecus (Figs. 1–3; Gervais 1872, 4 feet tall). This taxon has been at the focus of a bipedal/quadrupedal argument since the 1950s. (So have pterosaurs.) 

Huerzler 1949
considered this specimen, “the earliest known representative of the line that led to man.” The hand was capable of a precision grip, convergent with human ancestors. The relatively broad pelvis (Figs. 1–3) and short jaws with small canines and other teeth of Oreopithecus were once considered diagnostic for a place in the transition to human bipedality. 

Figure 1. Oreopithecus in situ traced with colors. This fossil is imperfectly preserved and the skull is crushed like an eggshell.

Figure 1. Oreopithecus in situ traced with colors. This fossil is imperfectly preserved and the skull is crushed like an eggshell. Some bones are easy to identify. Others are best guesses.  See figure 2 for the reconstruction. This is the Hürzeler 1949 specimen.

Other workers have disputed this.
Oreopithecus was considered a jungle/swamp dweller with adaptations for hanging by its long arms from overhead branches. Gibbons have not yet been tested in the LRT, but the size and proportions appear similar.

Figure 2. Tentative reconstruction of elements traced in the Oreopithecus in situ figure 1. Other elements added from other authors.

Figure 2. Tentative reconstruction of elements traced in the Oreopithecus in situ figure 1. Other elements attributed to Oreopithecus added from other authors. Due to disarticulation and/or loss, finger and toe bones are guesswork.

While the hand and pelvis proportions
(Fig. 3) were similar to those of hominins (humans and their bipedal kin), the foot (Fig. 2, from another specimen) definitely was not. This indicates convergence, which remains rampant within the LRT.

Oreopithecus has not yet been added to the LRT.

Figure 3. From Rook et al. 1999 comparing an Oreopithecus ilium to that of Homo and Hylobates.

Figure 3. From Rook et al. 1999 comparing an Oreopithecus ilium to that of Homo and Hylobates.

Carbon isotopes
suggest a diet of “energy-rich underground tubers and corms, or even aquatic vegetation,” according to Nelson 2016. This is consistent with an arboreal yet swampy environment.

References
Gervais P 1872. Sur un singe fossile d’un espèce non ancore décrite, qui a été découvert au monte Bamboli. Comptes Rendues de l’Académie des Sciences Paris, 74: 1217-1223.
Harrison T 1990. The implications of Oreopithecus for the origins of bipedalism, in Coppens, Y; Senut, B, Origine(s) de la Bipédie chez les Hominidés [Origin(s) of Bipedalism in Hominids.
Hürzeler J 1949. Neubeschreibung von Oreopithecus bambolii Gervais.- Schweizerische Palaeontologische Abhandlungen 66(5):1–20.
Köhler M and Moya-Sola S 2003. La evolución de Oreopithecus bambolii Gervais, 1872 (Primates, Anthropoidea) y la condición de insularidad. Coloquios de Paleontología, Vol. Ext. 1 (2003) 443-458.
Nelson SV 2016. Isotopic reconstructions of habitat change surrounding the extinction of Oreopithecus, the last European ape. American Journal of Physical Anthropology 160:254–271. https://doi.org/10.1002/ajpa.22970
Rook L, Bondioli L, Köhler M, Moya-Sola S and Macchiarelli R 1999. Oreopithecus was a bipedal ape after all: Evidence from the iliac cancellous architecture. Proceeding of the National Academy of Science USA 96:8795–8799.
Russo GA and Shapiro LJ 2013. Reevaluation of the lumbosacral region of Oreopithecus bambolii. Journal of Human Evolution, published online July 23, 2013; doi: 10.1016/j.jhevol.2013.05.004

wiki/Oreopithecus

Milwaukee Journal account of the Huerzeler Oreopithecus
Smithsonian Magazine account of Oreopithecus controversies
BBC account of Oreopithecus
SciNews account of Oreopithecus

Mesozoic mammals: Two views

Smith 2011 reported,
at the beginning of the Eocene, 55mya, “the diversity of certain mammal groups exploded.” These modern mammals”, according to Smith, ‘ consist of rodents, lagomorphs, perissodactyls, artiodactyls, cetaceans, primates, carnivorans and bats. Although these eight groups represent 83% of the extant mammal species diversity, their ancestors are still unknown. A short overview of the knowledge and recent progress on this research is here presented on the basis of Belgian studies and expeditions, especially in India and China.’

Contra the claims of Smith 2011
in the large reptile tree (LRT, 1354 taxa, subsets Figs. 2–4) prototherians are known from the late Triassic (Fig. 1). Both metatherians and eutherians are known from the Middle Jurassic. Many non-mammal cynodonts survived throughout the Mesozoic. In addition, the ancestors of every included taxon are known back to Devonian tetrapods.

Noteworthy facts after an LRT review (Fig. 1):

  1. All known and tested Mesozoic mammals (Fig. 1) are either small arboreal taxa or small burrowing taxa (out of sight of marauding theropods).
  2. All Mesozoic monotremes are more primitive than Ornithorhynchus and Tachyglossus (both extant).
  3. All Mesozoic marsupials are more primitive than or include Vintana (Late Cretaceous).
  4. All Mesozoic placentals are more primitive than Onychodectes (Paleocene).
Figure 1. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here.

Figure 1. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here.

Given those parameters
we are able to rethink which mammals were coeval with dinosaurs back on phylogenetic bracketing (= if derived taxa are present, primitive taxa must have been present, too).

Smith reports, “The earliest known mammals are about as old as the earliest dinosaurs and appeared in the fossil record during the late Trias around two hundred and twenty million years ago with genera such as Sinoconodon (pre-mammal in the LRT), Morganucodon (basal therian in the LRT) and Hadrocodium (basal therian in the LRT). However, the earliest placental mammals (Eutheria) were not known before the Early Cretaceous. Eomaia scansoria (not eutherian in the LRT) from the Barremian of Liaoning Province, China is the oldest definite placental and is dated from a hundred and thirty million years ago.”

Mesozoic Prototherians

  1. All included fossil taxa are Mesozoic. Two others are extant (Fig. 2).
Figure 2. Mesozoic prototherians + Megazostrodon, the last common ancestor of all mammals. Only two taxa (gray) are post-Cretaceous.

Figure 2. Mesozoic prototherians + Megazostrodon, the last common ancestor of all mammals. Only two taxa (gray) are post-Cretaceous.

Mesozoic Metatherians (Marsupials)

  1. Derived Vincelestes is Early Cretaceous, which means Monodelphis and Chironectes were present in the Jurassic.
  2. Derived Didelphodon is Late Cretaceous, which means sisters to Thylacinus through Borhyaena were also present in the Mesozoic.
  3. Derived Vintana is Late Cretaceous, which means sisters to herbivorous marsupials were also present in the Mesozoic.
Figure 3. Mesozoic metatherians (in black), later taxa in gray. Whenever derived taxa are present in the Mesozoic (up to the Late Cretaceous) then ancestral taxa, or their sisters, were also present in the Mesozoic. Didelphis is extant, but probably unchanged since the Late Jurassic/Early Cretaceous.

Figure 3. Mesozoic metatherians (in black), later taxa in gray. Whenever derived taxa are present in the Mesozoic (up to the Late Cretaceous) then ancestral taxa, or their sisters, were also present in the Mesozoic. Didelphis is extant, but probably unchanged since the Late Jurassic/Early Cretaceous.

Mesozoic Eutherians (= Placentals)

  1. Rarely are placental mammals identified from the Mesozoic, because many are not considered placentals.
  2. Placentals (in the LRT) are remarkably rare in the Mesozoic, but sprinkled throughout the cladogram, such that all taxa more primitive than the most derived Mesozoic taxon (Maelestes and derived members of the clade Glires, Fig. 4, at present a number of multituberculates) must have had Mesozoic sisters (Carnivora, Volitantia, basal Glires). 
Figure 4. Mesozoic euthrerians (placentals, in black). Later taxa in light gray. All taxa more primitive than Mesozoic taxa were likely also present in the Jurassic and Cretaceous. None appear after Onychodectes. Madagascar separated from Africa 165-135 mya, deep into the Cretaceous with a population of tenrecs attached. No rafting was necessary. 

Figure 4. Mesozoic euthrerians (placentals, in black). Later taxa in light gray. All taxa more primitive than Mesozoic taxa were likely also present in the Jurassic and Cretaceous. None appear after Onychodectes. Madagascar separated from Africa 165-135 mya, deep into the Cretaceous with a population of tenrecs attached. No rafting was necessary.

The above represents what a robust cladogram is capable of,
helping workers determine the likelihood of certain clades appearing in certain strata, before their discovery therein, based on their genesis, not their widest radiation or eventual reduction and extinction. In other words, we might expect sisters to basal primates, like adapids and lemurs, to be present in the Mesozoic, but not sisters to apes and hominids. We should expect sisters to all tree shrews and rodents to be recovered in Mesozoic strata. We should expect to see sisters to Caluromys, Vulpavus and other small arboreal therians/carnivorans in Mesozoic strata, but not cat, dog and bear sisters.

References
Smith T 2011. Contribution of Asia to the evolution and paleobiogeography of the earliest modern mammals. Bulletin des séances- Académie royale des sciences d’outre-mer. Meded. Zitt. K. Acad. Overzeese Wet.57: 293-305