Mirasaura, new diapsid with dorsal skin crest from Triassic of Germany (free pdf)
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Ben Creisler
Jul 23, 2025, 12:11:20 PM7/23/25
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Ben Creisler
Mirasaura grauvogeli gen. et sp. nov.
Stephan N. F. Spiekman, Christian Foth, Valentina Rossi, Cristina Gascó Martín, Tiffany S. Slater, Orla G. Bath Enright, Kathleen N. Dollman, Giovanni Serafini, Dieter Seegis, Léa Grauvogel-Stamm, Maria E. McNamara, Hans-Dieter Sues & Rainer R. Schoch (2025)
Triassic diapsid shows early diversification of skin appendages in reptiles
Nature (advance online publication)
doi: https://doi.org/10.1038/s41586-025-09167-9
https://www.nature.com/articles/s41586-025-09167-9
Complex integumentary appendages such as avian feathers and mammalian hair play a principal role in tetrapod evolution, with critical functions in insulation, sensation, display and flight. Although feathers and hair originated in the stem-lineages of birds and mammals, respectively, their underlying gene regulatory network has much deeper amniote roots. The early evolution of amniote integumentary appendages, however, remains poorly understood because of the absence of fossil evidence. Here we present Mirasaura grauvogeli, a small-sized diapsid from the Middle Triassic epoch (about 247 million years ago) with a distinctive crest formed by elongate integumentary appendages extending serially along its back, similar to those of the poorly understood Triassic reptile Longisquama. Despite its superficially bird-like skull, Mirasaura is not closely related to avemetatarsalians but instead belongs to the exclusively Triassic reptilian clade Drepanosauromorpha. Melanosomes preserved in its integumentary appendages are consistent in geometry with melanosomes of feathers but not those of reptilian skin or mammalian hair. Nevertheless, the morphology of the integumentary appendages and phylogenetic placement of Mirasaura indicate that they are not structurally homologous to feathers or other integumentary appendages in living amniotes. Our findings show that complex integumentary appendages are not restricted to avemetatarsalians and mammaliaforms among amniotes and evolved in a lineage basal to all extant reptiles, challenging our understanding of the evolution of the reptilian integument.
*****
News:
https://phys.org/news/2025-07-feather-crest-triassic-reptile-ideas.html
https://www.nytimes.com/2025/07/23/science/archaeology-feathers-dinosaurs-mirasaura.html
https://www.nationalgeographic.com/animals/article/crested-triassic-reptile
https://www.smithsonianmag.com/blogs/national-museum-of-natural-history/2025/07/23/paleontologists-discover-a-marvelous-triassic-reptile-that-sported-a-sail-of-feather-like-structures-on-its-back/
https://idw-online.de/en/news855741
A new paper:
Free pdf:
Mirasaura grauvogeli gen. et sp. nov.
Stephan N. F. Spiekman, Christian Foth, Valentina Rossi, Cristina Gascó Martín, Tiffany S. Slater, Orla G. Bath Enright, Kathleen N. Dollman, Giovanni Serafini, Dieter Seegis, Léa Grauvogel-Stamm, Maria E. McNamara, Hans-Dieter Sues & Rainer R. Schoch (2025)
Triassic diapsid shows early diversification of skin appendages in reptiles
Nature (advance online publication)
doi: https://doi.org/10.1038/s41586-025-09167-9
https://www.nature.com/articles/s41586-025-09167-9
Complex integumentary appendages such as avian feathers and mammalian hair play a principal role in tetrapod evolution, with critical functions in insulation, sensation, display and flight. Although feathers and hair originated in the stem-lineages of birds and mammals, respectively, their underlying gene regulatory network has much deeper amniote roots. The early evolution of amniote integumentary appendages, however, remains poorly understood because of the absence of fossil evidence. Here we present Mirasaura grauvogeli, a small-sized diapsid from the Middle Triassic epoch (about 247 million years ago) with a distinctive crest formed by elongate integumentary appendages extending serially along its back, similar to those of the poorly understood Triassic reptile Longisquama. Despite its superficially bird-like skull, Mirasaura is not closely related to avemetatarsalians but instead belongs to the exclusively Triassic reptilian clade Drepanosauromorpha. Melanosomes preserved in its integumentary appendages are consistent in geometry with melanosomes of feathers but not those of reptilian skin or mammalian hair. Nevertheless, the morphology of the integumentary appendages and phylogenetic placement of Mirasaura indicate that they are not structurally homologous to feathers or other integumentary appendages in living amniotes. Our findings show that complex integumentary appendages are not restricted to avemetatarsalians and mammaliaforms among amniotes and evolved in a lineage basal to all extant reptiles, challenging our understanding of the evolution of the reptilian integument.
*****
News:
https://phys.org/news/2025-07-feather-crest-triassic-reptile-ideas.html
https://www.nytimes.com/2025/07/23/science/archaeology-feathers-dinosaurs-mirasaura.html
https://www.nationalgeographic.com/animals/article/crested-triassic-reptile
https://www.smithsonianmag.com/blogs/national-museum-of-natural-history/2025/07/23/paleontologists-discover-a-marvelous-triassic-reptile-that-sported-a-sail-of-feather-like-structures-on-its-back/
https://idw-online.de/en/news855741
Ben Creisler
Jul 27, 2025, 5:58:16 PM7/27/25
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Ben Creisler
OK, making a big subject line correction... The fossils come from Alsace in France--even though the specimens are now in a museum in Germany. In a rush to post an interesting new paper, I skimmed through opening paragraphs of the article text and the news stories, and wrongly guessed that the fossils came from where the fossils are currently curated. I've now had a chance to read the content in detail. Apologies for messing up the patrimony issues...
Here are some additional related items:
Mysterious fossil may rewrite story of skin and feather evolution in reptiles
https://theconversation.com/mysterious-fossil-may-rewrite-story-of-skin-and-feather-evolution-in-reptiles-261695
====
Mirasaura - A ‘wonder’ fossil changes our understanding of reptile evolution
Naturkundemuseum Stuttgart
3 min.
https://theconversation.com/mysterious-fossil-may-rewrite-story-of-skin-and-feather-evolution-in-reptiles-261695
====
Mirasaura - A ‘wonder’ fossil changes our understanding of reptile evolution
Naturkundemuseum Stuttgart
3 min.
Jeff Hecht
Jul 29, 2025, 12:39:52 PM7/29/25
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The moment I saw the reconstruction in Carl Zimmer's NY Times story https://www.nytimes.com/2025/07/23/science/archaeology-feathers-dinosaurs-mirasaura.html? I noted the resemblance of Mirasaura to another odd Triassic reptile Longisquama insignis, which the late Larry Martin had proposed as a bird ancestor. That hypothesis has largely been abandoned, but but Mirasaura adds to a short list of rather weird early reptiles.
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Tim Williams
Jul 29, 2025, 10:19:51 PM7/29/25
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Jeff Hecht <je...@jeffhecht.com> wrote:
> I noted the resemblance of Mirasaura to another odd Triassic reptile Longisquama insignis, which the late
> Larry Martin had proposed as a bird ancestor. That hypothesis has largely been abandoned, but but Mirasaura
> adds to a short list of rather weird early reptiles.
> I noted the resemblance of Mirasaura to another odd Triassic reptile Longisquama insignis, which the late
> Larry Martin had proposed as a bird ancestor. That hypothesis has largely been abandoned, but but Mirasaura
> adds to a short list of rather weird early reptiles.
Yes, very weird indeed.
The hypothesis of a link between_Longisquama_ and birds goes back to the original description by Sharov in 1970. (I'm working off the English translation of Sharov's original paper). This was written at a time when the now-discredited 'pseudosuchian' origin of birds held sway. Based on the feather-like (sort of) dorsal appendages of _Longisquama_, plus the presence of what he regarded as furcula-like fused clavicles, Sharov thought _Longisquama_ was close to the unknown pseudosuchian group from which birds were thought to have originated.
Incidentally, Sharov created (and diagnosed) the family Longisquamidae - which is therefore available for any clade that comprises _Mirasaura_ and _Longisquama_.
Sharov appears to have been correct in reconstructing _Longisquama_ with a single row of dorsal appendages (not paired and more suitable for gliding). He nevertheless thought that they had a function in aerial locomotion.
The hypothesis of a link between_Longisquama_ and birds goes back to the original description by Sharov in 1970. (I'm working off the English translation of Sharov's original paper). This was written at a time when the now-discredited 'pseudosuchian' origin of birds held sway. Based on the feather-like (sort of) dorsal appendages of _Longisquama_, plus the presence of what he regarded as furcula-like fused clavicles, Sharov thought _Longisquama_ was close to the unknown pseudosuchian group from which birds were thought to have originated.
Incidentally, Sharov created (and diagnosed) the family Longisquamidae - which is therefore available for any clade that comprises _Mirasaura_ and _Longisquama_.
Sharov appears to have been correct in reconstructing _Longisquama_ with a single row of dorsal appendages (not paired and more suitable for gliding). He nevertheless thought that they had a function in aerial locomotion.
Mickey Mortimer
Jul 30, 2025, 3:36:24 AM7/30/25
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Indeeed, I summarized the supposed avian history of Longisquama on the database https://theropoddatabase.github.io/Non-theropods.htm#Longisquamainsignis
"Longisquama a bird ancestor? Another connection to dinosaurs has been the claim that Longisquama is related to the ancestor of birds. This originated with Sharov (1970), who believed the furcula and elongate forelimb scales were birdlike, but has more recently been popular among those arguing birds are not dinosaurs (beginning with Jones et al., 2000). Besides the furcula and forearm scales (which cannot be homologous with secondary feathers based on developmental data), Martin (2004) listed several other characters as being similar to birds- subdivided antorbital fenestra (absent as noted above), pointed snout (also in Coelurosauravus, simiosaurs, pterosaurs, most coelurosaurs, and numerous other taxa), "expanded cranium" (uncertain even if the supposed crest is really a displaced skull roof, as its three dimensional placement is unknown, as is endocranial size; also in Megalancosaurus, pterosaurs and coelurosaurs), elongate postorbital (vague and actually reduced in most birds, with even basal forms like Archaeopteryx having a shorter ventral ramus that ironically resembles Coelurosauravus more), absent mandibular fenestra (variable in basal birds and true of almost all non-archosauriforms), teeth with expanded roots (unverified as noted above), neck attaches low to skull (only true if the parietal crest is taken as part of the skull, and not actually true in basal birds like Archaeopteryx), strap-like scapula (also present in averostrans, simiosaurs, pterosaurs and to a lesser extent in Coelurosauravus), elongate manus (also in pterosaurs, coelurosaurs and many other taxa), elongate penultimate manual phalanges (untrue in digit I, and only homologous in Martin's view in digit IV; also present in Coelurosauravus, simiosaurs, pterosaurs and theropods), and feathers.
The supposed feather homologs of Longisquama have generated the most research since Jones et al. first redescribed them, and have since been more accurately described by Voigt et al. (2009). Jones et al. described a number of similarities to feathers, and it seems fitting to use Feduccia's (2002) term 'parafeather' for the structures. Though Haubold and Buffetaut (1987) proposed the parafeathers were paired and could be horizontally extended as gliding surfaces (a claim followed by Martin), there is no evidence of this and Voigt et al. noted any such 'thoracic wing' would be compromised by having the aerodynamic surfaces so distally placed. The cylindrical, tapered base is similar to follicular structures like feathers, though Voigt et al. noted some scales such as those on iguanid dorsal frills have this characteristic as well. However, the supposed transverse partitions homologized to avian pulp caps by Jones et al. (and claimed to be pedal phalanges by Peters, 2006) are actually transverse ridges on both sides of the parafeather's middle lobe. The supposed calamus walls surrounding them are the anterior and posterior lobes, which lack ridges basally (Voigt et al., 2009). While parafeathers look roughly feather-like distally in having a central shaft and surrounding vane, the actual structure is quite different. Instead of a hollow rachis and separate barbs to form the vane, Longisquama has a pair of membranes which join at their edges (Reisz and Sues, 2000) and enclose two longitudinal lobes distally, as the posterior lobe tapers out before the vane-like expansion. The shaft analog is a continuation of the boundary between the anterior and middle lobes (so is not even continuous with the basal 'calamus' as identified by Jones et al.), while the supposed barbs never separate even at the parafeather's tip and often merge (blamed on taphonomy by Jones et al.). Instead, the 'barbs' are transverse ridges in the continuous membrane. There seems to be an outer sheath on the base of each parafeather, which was homologized by Jones et al. with the sheaths on avian feathers. Resemblences to feathers thus seem limited to the cylindrical and tapered base and basal sheath. While parafeathers may be homologous to feathers at the level of the follicle, they are no more similar than the stage 1 feathers of Tianyulong, Kulindadromeus and basal coelurosaurs, the quills of Psittacosaurus or the pycnofibres of pterosaurs.
More recently, James and Pourtless (2009) have recovered Longisquama as the sister to Ornithes in their flawed cladistic analysis described above. This is actually more closely related to birds than hypothesized by Martin and Feduccia in their latest papers, as the latter have oviraptorosaurs and deinonychosaurs closer to Aves albeit outside Dinosauria. The characters listed under "Longisquama a theropod?" above for Maniraptora through Metornithes could thus also be used to defend relationships with birds in Feduccia's or Martin's view. In addition to those, the characters James and Pourtless recovered as shared with Ornithes are- scapula parallel to dorsal column (very untrue in Longisquama); ossified sternum absent (optimized in their topology this way due to alvarezsaurids and Caudipteryx being next most basal, but also true of most theropods, as well as many non-archosaurs such as Coelurosauravus and Protorosaurus).
Longisquama does not share any characters with birds not found in basal coelurosaurs, and can be excluded from Tetanurae based on numerous characters such as maxillary teeth extending posteriorly under the orbit, lacking an enlarged distal carpal I+II, and having phalanges on manual digit IV and having digit V, in addition to the non-dinosaurian characters noted in the previous section."
"Longisquama a bird ancestor? Another connection to dinosaurs has been the claim that Longisquama is related to the ancestor of birds. This originated with Sharov (1970), who believed the furcula and elongate forelimb scales were birdlike, but has more recently been popular among those arguing birds are not dinosaurs (beginning with Jones et al., 2000). Besides the furcula and forearm scales (which cannot be homologous with secondary feathers based on developmental data), Martin (2004) listed several other characters as being similar to birds- subdivided antorbital fenestra (absent as noted above), pointed snout (also in Coelurosauravus, simiosaurs, pterosaurs, most coelurosaurs, and numerous other taxa), "expanded cranium" (uncertain even if the supposed crest is really a displaced skull roof, as its three dimensional placement is unknown, as is endocranial size; also in Megalancosaurus, pterosaurs and coelurosaurs), elongate postorbital (vague and actually reduced in most birds, with even basal forms like Archaeopteryx having a shorter ventral ramus that ironically resembles Coelurosauravus more), absent mandibular fenestra (variable in basal birds and true of almost all non-archosauriforms), teeth with expanded roots (unverified as noted above), neck attaches low to skull (only true if the parietal crest is taken as part of the skull, and not actually true in basal birds like Archaeopteryx), strap-like scapula (also present in averostrans, simiosaurs, pterosaurs and to a lesser extent in Coelurosauravus), elongate manus (also in pterosaurs, coelurosaurs and many other taxa), elongate penultimate manual phalanges (untrue in digit I, and only homologous in Martin's view in digit IV; also present in Coelurosauravus, simiosaurs, pterosaurs and theropods), and feathers.
The supposed feather homologs of Longisquama have generated the most research since Jones et al. first redescribed them, and have since been more accurately described by Voigt et al. (2009). Jones et al. described a number of similarities to feathers, and it seems fitting to use Feduccia's (2002) term 'parafeather' for the structures. Though Haubold and Buffetaut (1987) proposed the parafeathers were paired and could be horizontally extended as gliding surfaces (a claim followed by Martin), there is no evidence of this and Voigt et al. noted any such 'thoracic wing' would be compromised by having the aerodynamic surfaces so distally placed. The cylindrical, tapered base is similar to follicular structures like feathers, though Voigt et al. noted some scales such as those on iguanid dorsal frills have this characteristic as well. However, the supposed transverse partitions homologized to avian pulp caps by Jones et al. (and claimed to be pedal phalanges by Peters, 2006) are actually transverse ridges on both sides of the parafeather's middle lobe. The supposed calamus walls surrounding them are the anterior and posterior lobes, which lack ridges basally (Voigt et al., 2009). While parafeathers look roughly feather-like distally in having a central shaft and surrounding vane, the actual structure is quite different. Instead of a hollow rachis and separate barbs to form the vane, Longisquama has a pair of membranes which join at their edges (Reisz and Sues, 2000) and enclose two longitudinal lobes distally, as the posterior lobe tapers out before the vane-like expansion. The shaft analog is a continuation of the boundary between the anterior and middle lobes (so is not even continuous with the basal 'calamus' as identified by Jones et al.), while the supposed barbs never separate even at the parafeather's tip and often merge (blamed on taphonomy by Jones et al.). Instead, the 'barbs' are transverse ridges in the continuous membrane. There seems to be an outer sheath on the base of each parafeather, which was homologized by Jones et al. with the sheaths on avian feathers. Resemblences to feathers thus seem limited to the cylindrical and tapered base and basal sheath. While parafeathers may be homologous to feathers at the level of the follicle, they are no more similar than the stage 1 feathers of Tianyulong, Kulindadromeus and basal coelurosaurs, the quills of Psittacosaurus or the pycnofibres of pterosaurs.
More recently, James and Pourtless (2009) have recovered Longisquama as the sister to Ornithes in their flawed cladistic analysis described above. This is actually more closely related to birds than hypothesized by Martin and Feduccia in their latest papers, as the latter have oviraptorosaurs and deinonychosaurs closer to Aves albeit outside Dinosauria. The characters listed under "Longisquama a theropod?" above for Maniraptora through Metornithes could thus also be used to defend relationships with birds in Feduccia's or Martin's view. In addition to those, the characters James and Pourtless recovered as shared with Ornithes are- scapula parallel to dorsal column (very untrue in Longisquama); ossified sternum absent (optimized in their topology this way due to alvarezsaurids and Caudipteryx being next most basal, but also true of most theropods, as well as many non-archosaurs such as Coelurosauravus and Protorosaurus).
Longisquama does not share any characters with birds not found in basal coelurosaurs, and can be excluded from Tetanurae based on numerous characters such as maxillary teeth extending posteriorly under the orbit, lacking an enlarged distal carpal I+II, and having phalanges on manual digit IV and having digit V, in addition to the non-dinosaurian characters noted in the previous section."
Mirasaura shows Longisquama's cranium really is expanded and not a Coelurosauravus-type crest. Going to have to update that entry...
Interestingly, Spiekman et al. say regarding Longisquama "The element identified as a furcula is a continuously and prominently curved element in the anteriormost region of the ribcage. The presence of a ‘furcula-like’ fused clavicle would not contradict the identification of Longisquama insignis as a drepanosauromorph since coossified clavicles also occur in this clade32. However, the element is continuously curved, which contrasts with the distinctly V-shaped furculae known for both drepanosauromorphs and avian-line archosaurs, and thus we consider the identification of this element as co-ossified clavicles unlikely." Considering the same shape difference exists between the furculae of e.g. Velociraptor and Bambiraptor, I don't see it as unexpected to be different between longisquamids and drepanosaurids.
Needless to say, Mirasaura's 24 dorsals, two sacrals, single-headed ribs, tall ilium with no preacetabular process, etc. put the final nail in the nail-ridden coffin of James and Pourtless' (2009) recovery of longisquamids as coelurosaurian theropods.
Mickey Mortimer
Dawid Mazurek
Jul 30, 2025, 6:47:54 AM7/30/25
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Since drepanosaurids was found outside Sauria by Spiekman et al. (2025), wouldn't that make Simiosauria having priority over Drepanosauromorpha?
Ethan Schoales
Jul 30, 2025, 12:40:08 PM7/30/25
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If a group is above superfamily level or unranked, the ICZN doesn’t apply to it (though perhaps it should).
On Wed, Jul 30, 2025 at 6:47 AM Dawid Mazurek <dawidma...@gmail.com> wrote:
Since drepanosaurids was found outside Sauria by Spiekman et al. (2025), wouldn't that make Simiosauria having priority over Drepanosauromorpha?
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Dawid Mazurek
Jul 30, 2025, 12:53:13 PM7/30/25
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Well, yes, but I thought priority is a community rule. If not, that sounds like a big problem.
Jaime Headden
Jul 30, 2025, 1:37:37 PM7/30/25
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Both can be used. RegNum lacks both, so unless it's just not getting updated and the people going around converting names aren't doing due diligence by adding them to the database, I really have to wonder if the registration timing/dates matter. But anyways, it's possible -- if they're not -- both can be converted and defined to avoid this issue. Assume Simiosauria is the more inclusive of the two, whereas Drepanosauromorpha is exclusive of Longisquama? Both now have value apart from one another.
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Jaime A. Headden
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Mickey Mortimer
Aug 1, 2025, 4:56:39 PM8/1/25
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"Well, yes, but I thought priority is a community rule. If not, that sounds like a big problem."
Once you get outside the realm of the ICZN, it's really more about which suprafamilial taxa catch on then which were proposed first. Goniopoda vs. Theropoda, Protoavia vs. Maniraptoriformes, Segnosauria and Segnosaurischia vs. Therizinosauria, Caenagnathiformes vs. Oviraptorosauria, Omnivoropterygiformes vs. Sapeornithiformes, Ornithopectae vs. Ornithothoraces, and Odontolcae, Odontognathes and Dromaeopappi vs. Hesperornithes for Mesozoic theropods for instance. Then when you get groups that have been argued about for even longer like crown birds or high level amniote classification there are all sorts of archaic names proposed that are no longer followed.
Mickey Mortimer
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