A bit on theropod footprints (
see also: link ->):
Many huge taxa, some potential record holders from various time periods are only known from footprints. This is also seen in sauropods and perhaps ceratopsians and ornithopods.
www.app.pan.pl/archive/published/app57/app20100119.pdfwww.app.pan.pl/archive/published/app46/app46-441.pdfwww.cprm.gov.br/publique/media/Art_footprints_silva.pdfwww.researchgate.net/publication/242229671_ESTIMATING_SPEEDS_OF_DINOSAURS_FROM_TRACKWAYS_A_REEVALUATION_OF_ASSUMPTIONSPrints above 40-50cm are usually considered to be very large (even gigantic in some strata). It is general consensus (based on hip-height equations, observation of skeletons, estimates and guesstimates by scientists, figures from papers like the one on
Bautakioutichtium or
Eobrontes) that a 50cm footprint would correspond to at least the size of a medium to large specimen of
Allosaurus (8-9m TL, 1.5-1.8m hip height, ~2t).
Any precise size figure is of course highly prone to be wrong, but some of these are undoubtedly contenders When it comes to the largest theropod.
Also I would like to add while footprints can get enlarged artificially (by means of slippage or possibly tektonics), as everybody seems very keen to remark, they can become smaller just as easily (collapsing walls, infillment with sediments, toemark pinching, roofing, Farlow et al. 2012), so if no obvious reason to suspect deformation is present, we could and should assume them as valid.
The largest theropod prints I am aware of are the following specimens:docentes.fct.unl.pt/sites/default/files/omateus/files/mateus__milan_2010_-_diverse_l_j_ichnofauna_from_lourinha_fm_portugal.pdf79cm (96cm including the metatarsal), tentatively referred to
Torvosaurus sp. gurneyi (imo not valid since
T. sp. T. gurneyi isn't even close to the size of the animal that left this print), Lourinha
82cm (103cm including metatarsal), different morphology, Asturias
•
www.academia.edu/1209417/Rastrilladas_de_icnitas_teropodas_gigantes_del_Jurasico_Superior_Sinclinal_de_Iouaridene_Marruecos_3 different trackways, all tracks averaging at over 70cm, Kimmeridgian of Morroco
19IGR: 90cm, isolated
20IGR, 25IGR: average 77cm, maximum 82cm
13IGR, 16IGR, 21IGR: average 75cm, maximum 80cm
According to the authors, these belong to theropods from "3.4-4.4m in height" and "between 10 and 19m long".
Results using Tony Thulborn’s morphometric formula for large theropods (sum of metatarsal3, tibia and femur=FL×4.9) are 441, 375 and 369cm respectively, which is rather conservative since the prints do not seem to include much of the metatarsals or claws.
•
www.academia.edu/1047721/A_Probable_Tyrannosaurid_Track_from_the_Hell_Creek_Formation_Upper_Cretaceous_Montana_United_States72cm long from Hell Creek (about the size of FMNH PR 2081?), but maybe hadrosaurian in origin (lenght/width-ratio)
Result using Thulborn’s formula: 353cm
•
www.tandfonline.com/doi/abs/10.1080/1042094940938639086cm,
Tyrannosauripus pilmorei, New Mexico, includes metatarsal impression and decently-preserved claws
•
Tyrannosauropus petersoni (81cm long, but at one time misscaled to be 140cm) is pretty enigmatic and may be from a hadrosaur (the lenght/width ratio, presence of claws and lenght of the digits are important features, but this is very unsure).
There have been (published, in peer reviewed documents) myths about a 1.3m footprint from the Kimmeridgian, but as it turns out it was left by a sauropod.
On the reliability issue:
1.
blaze noted that Stan's feet were about the same size as Sue's. I think this is due to ontogenic reasons. Younger animals typically have larger feet, and Stan is younger than Sue. So they may not actually be unambiguous evidence for the size of the animal that left them when it left them, but they can still give show how large the taxon could grow.
2. Short note on the Morroccan tracks: the authors give a very rough size figure of 10-19m for the trackmaker, and a hip height of 340-440cm (both the latter figures would be indicative of animals much larger than 10m, just for the protocol). Even the lower figure is 10cm longer than the total stretched-out leg of FMNH PR 2081 including the whole pes, in collumnar posture). They convincingly (that is, as far as my Latin takes me) argue these tracks are the largest yet found, and the largest tracks from three different trackway are all 80cm or more (being 75, 77 and 90cm on average respectively).
3. Most other huge tracks that approach such dimensions are more dubious, and either include metatarsi and halluxes, are supposed to belong to hardosaurs or other things.
4. The Hell Creek track seems to come reasonably close to the size of a large Tyrannosaur track.
5. Theropod tracks are not likely to get greatly enlarged by deformation in terms of lenght, and if, theirdistinctive shape should make this easy to spot, and it is usually noted when present (eg. Boutakiout et al. seem to exclude deformed tracks and note when there is a metatarsal impression enlarging the print).
On the whole, ichnology gives a good idea of the size potential of animals from certain strata, and can help us understand ecosystems not completely known from body fossils. This also adds notably to the list of giant theropods (as well as sauropods, ornithopods and ceratopsians).
