("The Mayo family's Patagonian titan"), the Chubut Monster, is a species of gigantic titanosaurian sauropod that lived on what is now Patagonia, Chubut Province of Argentina, South America during the Albian stage of the Middle Cretaceous. It was first excavated and exposed to the media in 2014, and described in 2017.
It was initially speculated to be ~37 metres long, with a femur stated to be in various sizes ranging from ~2.4 metres to ~3 metres. The measurements in the description then showed that the gigantic ~37-metre figure as implausible for any of the known specimens given regular titanosaur proportions.
It is commonly famed for being larger than Argentinosaurus
, however, this seems to be an exaggeration for the known specimens. However, its transverse width is still greater than in Argentinosaurus
, suggesting a proportionally wide ribcage.
I initially had a loose guess that this creature would turn out ~35 metres long or more before this skeletal reconstruction, but after working on it, I figured that this may be a bit excessive for the known specimens. However, given that the holotype has an unfused scapulacoracoid and that bone histology analysis found the known individuals to be subadults, adults would have grown larger than in these reconstructions. The schematic skeletal in the description was subpar to say the least, but it sufficed in very rough shapes for many of the bones.
specimens were complete enough as a whole to base most of the proportions on other conspecific specimens rather than related taxa. The holotype MPEF-PV 3400 and paratype MPEF-PV 3399 were cross-scaled via the 8th dorsal, which overlaps between them in an uncrushed and unbroken state. MPEF-PV 3397 and the rest of the paratypes were composited into one and scaled down from the holotype reconstruction. The sacrum, ilium, lower hindlimb proportions, and humerus:femur proportions were based on Futalognkosaurus
. Since illustrations of the caudals are quite scarce, and the description's schematic doesn't have them in a good-enough resolution to use, many of the caudals were roughly illustrated using Dreadnoughtus
. The cervical count was reduced from the 15 used in the description to 14, based on Futalognkosaurus
. And since the anterior dorsals were quite crushed, cross-scaled Futalognkosaurus
dorsals were used to estimate their uncrushed lengths. The skull is a speculative transitional morph based on a cross between Tapuiasaurus
, and Narambuenatitan
The left and right femora in MPEF-PV 3399 and humeri of the MPEF-PV 3397 + other paratypes composite were swapped in the lateral view skeletals in order to show off the preserved and illustrated elements. Bones which are well-illustrated in the description or external photographs are in white, while bones which are unillustrated or poorly-illustrated are in light grey. Illustrated bones with unspecified specimens in the description's figures (such as the first caudal) are marked as illustrated in all specimens which preserve said bone.
Measurements for MPEF-PV 3400:
Hip height: ~4.76 metres
Shoulder height: ~5.48 metres
Total height: ~13.21 metres
Standing length: ~26.5 metres
Axial length: ~30.82 metres
Measurements for MPEF-PV 3397 + other paratypes, scaled to MPEF-PV 3397:
Hip height: ~4.29 metres
Shoulder height: ~4.94 metres
Total height: ~11.9 metres
Standing length: ~23.88 metres
Axial length: ~27.77 metres
Measurements for MPEF-PV 3399:
Hip height: ~4.75 metres
Shoulder height: ~5.25 metres
Total height: ~12.33 metres
Standing length: ~26.83 metres
Axial length: ~30.79 metres
Carballido et al., 2017, "A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs"
Calvo et al., 2007, "Anatomy of Futalognkosaurus dukei Calvo, Porfiri, Gonzales Riga & Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquen Group(Late Cretaceous), Patagonia, Argentina"
Gomani, 2005, "Sauropod dinosaurs from the Early Cretaceous of Malawi, Africa"
Filippi et al., 2010, "A new titanosaur sauropod dinosaur from the Upper Cretaceous of North Patagonia, Argentina"
Wilson et al., 2016, "The skull of the titanosaur Tapuiasaurus macedoi (Dinosauria: Sauropoda), a basal titanosaur from the Lower Cretaceous of Brazil"
Calvo, 2014, "New fossil remains of Futalognkosaurus dukei (Sauropoda: Titanosauria) from the Late Cretaceous of Neuquen, Argentina"
Lacovara et al., 2014, "A gigantic, exceptionally complete titanosaurian sauropod dinosaur from southern Patagonia, Argentina"
Gonzalez-Riga et al., 2016, "A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot"
Greg Paul, 2016, "The Princeton Field Guide to Dinosaurs"Scott Hartman's FutalognkosaurusPatagotitan arm photoPatagotitan femur photo 1Patagotitan femur photo 2Patagotitan mount photo 1Patagotitan mount photo 2Patagotitan mount photo 3
UPDATE(4/29/2018): Added detail, replaced the skull, and scalebar updated to my new conventions. See the previous version
here for comparison.