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Description
3/31/22 - General revision to the silhouette (particularly in the neck) based on the recent Woodruff, et al. 2022 paper.

Brontosaurs part 3! This time it's the very unique but never before restored Brontosaurus yahnahpin. Despite being quite incomplete when compared to many other apatosaurines, what is known of B. yahnahpin showcases some very unique features for this group. The posteriormost cervical centrum is significantly more wedge-shaped than other apatosaurines, & would suggest B. yahnahpin held its neck higher habitually than other brontosaurs, & may very well have been better suited for high browsing than the later taxa. This is also supported by the forelimb, which is slightly longer proportionally than is seen in the other Brontosaurus species.
A potentially taxonomy-altering character is present in the posteriormost preserved rib. This rib, considered to be Dr10, points backwards from the vertebrae when articulated, seemingly coming into contact with the ilium. This would mean that this dorsal rib was functioning more like a sacral rib than a traditional dorsal, & therefore than the posteriormost dorsal was actually in fact absorbed into the sacrum. This would give B. yahnahpin a total of six sacrals, completely unheard of within Diplodocoidea, & only seen in Somphospondyli. This also cuts the torso down to nine dorsals, a feature shared only with Barosaurus & potentially Supersaurus, however both of these taxa forgo the dorsal for an additional cervical instead. If this assessment is correct, I believe this would be strong grounds on which to separate yahnahpin from both Apatosaurus & Brontosaurus, & instead revive Bakker's Eobrontosaurus designation.
Finally, Tate-001 preserves a nearly complete gastral basket. Isolated gastralia have been found for several sauropods, & both the basal eusauropod Jobaria as well as the derived titanosaur Diamantinasaurus preserve these elements. Combined with Tate-001, this would seem to strongly imply most (if not all) sauropods possessed gastralia.

Description
3/31/22 - General revision to the silhouette (particularly in the neck) based on the recent Woodruff, et al. 2022 paper.

Brontosaurs part 3! This time it's the very unique but never before restored Brontosaurus yahnahpin. Despite being quite incomplete when compared to many other apatosaurines, what is known of B. yahnahpin showcases some very unique features for this group. The posteriormost cervical centrum is significantly more wedge-shaped than other apatosaurines, & would suggest B. yahnahpin held its neck higher habitually than other brontosaurs, & may very well have been better suited for high browsing than the later taxa. This is also supported by the forelimb, which is slightly longer proportionally than is seen in the other Brontosaurus species.
A potentially taxonomy-altering character is present in the posteriormost preserved rib. This rib, considered to be Dr10, points backwards from the vertebrae when articulated, seemingly coming into contact with the ilium. This would mean that this dorsal rib was functioning more like a sacral rib than a traditional dorsal, & therefore than the posteriormost dorsal was actually in fact absorbed into the sacrum. This would give B. yahnahpin a total of six sacrals, completely unheard of within Diplodocoidea, & only seen in Somphospondyli. This also cuts the torso down to nine dorsals, a feature shared only with Barosaurus & potentially Supersaurus, however both of these taxa forgo the dorsal for an additional cervical instead. If this assessment is correct, I believe this would be strong grounds on which to separate yahnahpin from both Apatosaurus & Brontosaurus, & instead revive Bakker's Eobrontosaurus designation.
Finally, Tate-001 preserves a nearly complete gastral basket. Isolated gastralia have been found for several sauropods, & both the basal eusauropod Jobaria as well as the derived titanosaur Diamantinasaurus preserve these elements. Combined with Tate-001, this would seem to strongly imply most (if not all) sauropods possessed gastralia.