Tanycolagreus compared to Yutyrannus

Tanycolagreus topwilsoni (Carpenter et al., 2005, Late Jurassic, TPII 2000-09-29, 3.3m, restored skeleton based on several specimens) was originally considered a coelurid, then a basal tyrannosauroid by several authors. The large reptile tree nests it with the much larger Yutyrannus, but with a relatively longer neck and longer tail.

Figure 1. Tanycolagreus compared to Yutyrannus.

Figure 1. Tanycolagreus compared to Yutyrannus.

Yutyrannus huali (Xu et al. 2012 ZCDM V5000 Zhucheng Dinosaur Museum, Shandong, Lower Cretaceous Yixian Formation) was originally considered a tyrannosauroid theropod likeT-rex. Here it nests as a sister to Tanycolagreus derived from a sister to Sinraptor. Note the lacrimal horns, large three-fingered hand and long torso. Yutyrannus is famous for being a giant feathered theropod, several times larger than the next largest contender.

Figure 2. Yutyrannus skull compared to Tanycolagreus.

Figure 2. Yutyrannus skull compared to Tanycolagreus.

References
Carpenter K, Miles C and Cloward K 2005. New small theropod from the Upper Jurassic Morrison Formation of Wyoming. in Carpenter, K. 2005. The Carnivorous Dinosaurs, Indiana University Press: 23-48
Xu X, Wang K, Zhang K, Ma Q, Xing L, Sullivan C, Hu D, Cheng S, Wang S et al. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature 484 (7392): 92–95. doi:10.1038/nature10906. PDF here.

wiki/Yutyrannus
wiki/Tanycolagreus

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The hands of Juravenator

There’s a tiny disarticulated fourth finger hidden in there…
that was originally overlooked (Fig. 1, in pink).

Figure 1. The hands of Juravenator in situ and reconstructed. Note on the left hand, digit 2 is lateral. Somehow digit 3 has moved below it.

Figure 1. The hands of Juravenator in situ and reconstructed. Note on the left hand, digit 2 is lateral. Somehow digit 3 has moved below it. The grayscale drawing is from the original paper.

Oddly, in the left hand
(Fig. 1) digit 3 ended up between digits 1 and 2.

See how DGS (digital graphic segregation) can be helpful?
Try it yourself. It just clarifies things and make reconstructions easy without changing the traced data, even by one pixel.

Careful readers will note
that few PILs (parallel interphalangeal lines) can be drawn through the joints here. Probably they come into alignment only when the fingers are curled (flexed) as in the human hand (try it yourself!). I say ‘probably’ because these need to be 3D modeled to test the possibility. Metacarpals do align. So do m1.2, m2.2 and m3.3.

Figure 4. Juravenator reconstructed. Note the many similarities with Compsognathus (Fig. 3).

Figure 2. Juravenator reconstructed. Note the many similarities with Compsognathus (Fig. 3).

References
Chiappe LM and Göhlich UB 2010. Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany.Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen, 258(3): 257-296. doi:10.1127/0077-7749/2010/0125
Göhlich UB and Chiappe LM 2006. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago. Nature 440: 329-332.
Göhlich UB, Tischlinger H and Chiappe LM 2006. Juravenator starki (Reptilia, Theropoda) ein nuer Raubdinosaurier aus dem Oberjura der Suedlichen Frankenalb (Sueddeutschland): Skelettanatomie und Wiechteilbefunde. Archaeopteryx, 24: 1-26.

wiki/Compsognathus
wiki/Juravenator

 

Another furcula in a bigger Compsognathus

Yesterday we looked at overlooked bits and pieces in the holotype Compsognathus. Today, pretty much the same with the newer larger specimen.

Figure 1. Forelimb of the large Compsognathus CM79. Here DGS recovered a digit 4, feather impressions, a furcula and sternum overlooked originally.

Figure 1. Forelimb of the large Compsognathus CNJ79. Here DGS recovered a digit 4, feather impressions, a dorsal scapula tip, a furcula and sternum overlooked originally.

The much larger and probably not congeneric
CNJ79 specimen of Compsognathus ((Bidar et al. 1972b; Peyer 2006; CNJ79; Late Jurassic) also has a few overlooked bits and pieces. 

Figure 1. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here. There may be an external mandibular fenestra. Hard to tell with the medial view and shifting bones.

Figure 2. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here.

Another tiny furcula
was identified by the authors in Juravenator (Fig. 3), a close relative of the two Compsognathus taxa.

Figure 3. Juravenator clavicles/furcula identified by Göhlich et al. 2006.

Figure 3. Juravenator clavicles/furcula identified by Göhlich et al. 2006, similar to those found in Compsognathus.

Whereas
the little holotype Compsognathus gave rise to ornithomimosaurs and tyrannosaurs, the large Compsognathus gave rise to Juravenator, Sinosauropteryx, therizinosaurs and oviraptorids.

Figure 4. Juravenator reconstructed. Note the many similarities with Compsognathus (Fig. 3).

Figure 4. Juravenator reconstructed. Note the many similarities with Compsognathus (Fig. 3).

References
Bidar AL, Demay L and Thomel G 1972b. Compsognathus corallestris,
une nouvelle espèce de dinosaurien théropode du Portlandien de Canjuers (Sud-Est de la France). Annales du Muséum d’Histoire Naturelle de Nice 1:9-40.
Chiappe LM and Göhlich UB 2010. Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany.Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen, 258(3): 257-296. doi:10.1127/0077-7749/2010/0125
Göhlich UB and Chiappe LM 2006. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago. Nature 440: 329-332.
Göhlich UB, Tischlinger H and Chiappe LM 2006. Juravenator starki (Reptilia, Theropoda) ein nuer Raubdinosaurier aus dem Oberjura der Suedlichen Frankenalb (Sueddeutschland): Skelettanatomie und Wiechteilbefunde. Archaeopteryx, 24: 1-26.
Peyer K 2006. A reconsideration of Compsognathus from the upper Tithonian of Canjuers, southeastern France, Journal of Vertebrate Paleontology, 26:4, 879-896,

wiki/Compsognathus
wiki/Juravenator

The premaxilla of Halszkaraptor: shorter than they thought.

Figure 1. Halszkaraptor images from Cau et al. Note the reconstruction with a too long premaxilla (red circle).

Figure 1. Halszkaraptor images from Cau et al. Note the reconstruction with a too long premaxilla (red circle). Short nore: the gastralia shown here evidently were not present in the fossil, but were imagined into place. Halszkaraptor nests with Shuvuuia, which also lacks gastralia. Let me know if either is incorrect. 

Originally described
by Cau et al. 2018 with 11 (x2) premaxillary teeth, Halszkaraptor stands out for having seven too many teeth in the premaxilla compared to all sister candidates. A closer look at the premaxilla reveals a mouth full of teeth, but the premaxilla has only four (x2) teeth. Cau et al. were kind enough to publish several views of the rostrum (Fig. 2).

Figure 1. The premaxilla and maxilla of the troodontid dinosaur Halszkaraptor shows the premaxilla is shorter with fewer teeth than originally described.

Figure 2. The premaxilla and maxilla of the troodontid dinosaur Halszkaraptor shows the premaxilla is shorter with fewer teeth than originally described.

Not alone on the cladogram.
Halszkaraptor is joined by Haplocheirus, which also has a similar short premaxilla (Fig. 3).

Figure 3. Haplocheirus nests close to Halszkaraptor in the LRT and has a similar short premaxilla.

Figure 3. Haplocheirus nests close to Halszkaraptor in the LRT and has a similar short premaxilla.

References
Cau A, et al. 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. doi:10.1038/nature24679

wiki/Halszkaraptor
wiki/Shuvuuia
wikiHaplocheirus

Theropods in the LRT with suggested nomenclature

Figure 1. Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently.

Figure 1. Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently. Names posted here are in use traditionally, but with different definitions in some cases.

Just a moment to update
the theropod subset of the large reptile tree (LRT, 1151 taxa). Given the present taxon list, this is the order they fall into using the generalized characters used throughout the LRT. Validation is required for all such first-time proposals. The names applied here are used in traditional studies, but often not following previous definitions or clade memberships.

The large and small Compsognathus specimens
are closely related, but not congeneric (Fig. 2).

Figure 1. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here. There may be an external mandibular fenestra. Hard to tell with the medial view and shifting bones.

Figure 2. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here. There may be an external mandibular fenestra. Hard to tell with the medial view and shifting bones.

Does anyone see
in this list two ‘related’ taxa that do not resemble one another more so than any other taxon? If so, that needs to be noted and repaired.

Halszkaraptor: what a story!

Published in Nature today
a Mongolian Late Cretaceous theropod that was rescued from the black market! It is supposed to be aquatic… but is it?

Figure 1. Halszkaraptor escuillei was originally considered an aquatic basal dromaosaur, but here nests with Shuvuuia, a sprinting biped.

Figure 1. Halszkaraptor escuillei was originally considered an aquatic basal dromaosaur, but here nests with Shuvuuia, a sprinting biped. It might not have been this chubby in the torso. All art is from Cau et al. 2017.

Halszkaraptor escuilliei (Cau et al. 2017; Late Cretaceous, Fig. 1) was originally considered an aquatic basal dromaeosaur related to Mahakala, but here Halszkaraptor nests with ShuvuuiaHaplocheirus and other non-aquatic sprinting dromaeosaurids. Manual digit 3 was the longest, but the thumb had the largest claw. The naris was displaced posteriorly. The fossil is preserved in 3D, largely articulated.

Figure 1. Shuvuuia and Mononykus to scale in various poses. The odd digit 1 forelimb claws appear to be retained for clasping medial cylinders, like tree trunks. The forelimb is very strong. Perhaps these taxa rest vertically and run horizontally. Click to enlarge.

Figure 2. Shuvuuia and Mononykus to scale in various poses. The odd digit 1 forelimb claws appear to be retained for clasping medial cylinders, like tree trunks. The forelimb is very strong. Perhaps these taxa rest vertically and run horizontally. Click to enlarge.

The Cau et al. cladogram
has many more bird-like theropods than the LRT. The taxa that nest together with Halszkaraptor in the LRT are sprinkled throughout the Cau et al. cladogram. In fact, all of the theropods that the two cladograms have in common nest in completely different nodes and leaves, except Haplocheirus nests in the same clade as Shuvuuia in both trees. Is this a case of taxon exclusion on the part of the LRT? Or just what happens when you score different traits? No reconstructions of sister taxa were provided.

FIgure 2. Subset of the LRT focusing on pre-bird theropods.

FIgure 2. Subset of the LRT focusing on pre-bird theropods. The taxa in the Velociraptor clade are sprinkled throughout the Cau et al. cladogram of theropods.

Let’s look at the pertinent parts of the Cau et al. abstract:
“Propagation X-ray phase-contrast synchrotron microtomography of a well-preserved maniraptoran from Mongolia, still partially embedded in the rock matrix, revealed a mosaic of features, most of them absent among non-avian maniraptorans but shared by reptilian and avian groups with aquatic or semiaquatic ecologies.

“This new theropod, Halszkaraptor escuillieigen. et sp. nov., is related to other enigmatic Late Cretaceous maniraptorans from Mongolia in a novel clade at the root of Dromaeosauridae. This lineage adds an amphibious ecomorphology to those evolved by maniraptorans: it acquired a predatory mode that relied mainly on neck hyperelongation for food procurement, it coupled the obligatory bipedalism of theropods with forelimb proportions that may support a swimming function, and it developed postural adaptations convergent with short-tailed birds.”
What about this theropod screams, “I’m aquatic!!” ?? This is one I just don’t see.
In the LRT
Halszkaraptor does not nest with other aquatic taxa. The neck is not particularly long compared to coeval Mononykus (Fig. 2), which has never been considered aquatic. The skull is very much like that of coeval Shuvuuia
Described in the press
as one of the oddest fossil yet found. This adjective usually gets attached to errors in identification. Halszkaraptor is not that odd. NatGeo reports, “Like modern aquatic predators, this dinosaur’s face seems to have had an exquisite sense of touch, useful for finding prey in murky waters. Its small teeth would have helped it nab tiny fish, and its limber backbone and flipper-like forelimbs suggest that it cut through the water with ease.”
This added later:
Apparently others have also seen the Shuvuuia connection. Author Andrea Cau listed 25 traits here that distinguish Halszkaraptor from Shuvuuia, but are found in dromaeosaurids. Perhaps this could all be cleared up easily, because in the LRT, Shuvuuia IS also a dromaeosaurid, not a distantly related theropod, as it nests in Cau et al. 2017.

References
Cau A, et al. 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. doi:10.1038/nature24679

wiki/Halszkaraptor
wiki/Shuvuuia