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Large Sauropod Tracks Juvenile Sauropod Tracks Theropod Tracks Metatarsal Tracks Small Theropod Tracks Squiggle Marks Miscellaneous Wide shots Site Workers Site Visitors Mud-collapsed and Overlapping Tracks Site Maps High Overhead Photos Photomosaics and Satellite Images

Ballroom Site Summary Introduction and Site History The Ballroom site was named for the remarkable quantity and density of dinosaur tracks at this site (of varying size, quality, and depth, and going in many different directions, and many overlapping), suggestive of a prehistoric dance floor. It includes several hundred tracks, representing two main types of dinosaurs (theropods and sauropods), possibly representing three or more species. The site is located just south of the Blue Hole. One can easily walk to the Ballroom from the Blue Hole, or access it more directly by walking down the trail marked "Equestrian Area" (for horseback riders) at the south end of the parking lot directly across from the park gift shop parking lot. For many years I and other workers and visitors were able to dimly see many tracks tracks at the site under shallow water and mud, and to map a handful of tracks on the narrow "Parlor" section, but were unable to clearly see or document most of the tracks on the site. However, during a fairly dry summer in 2009, paleontologist James O. Farlow of Indiana/Purdue University organized the so-called "Big Mapping Project", partially funded by a grant from the National Geographic Society, which included the systematic cleaning and further mapping of the Ballroom and every other major site in the park known at the time. I say "further mapping" because hundreds of tracks had already been mapped at several sites by myself (often with assistance from Dr Ron Hastings or others) at several Paluxy sites, though more remained to be mapped (or further mapped) at several sites. I was priviledged to join the Big Mapping Project, which also involved over a dozen graduate students, volunteers, and several other track workers. One of them, Mike O'Brien, was a graphics artist at Texas Parks and Wildlife Department who devised a system using a remote-controlled camera mounted on a high pole, along with movable metric grids laid on the track floor, to produce large, high-resolution maps of the site, and construct dramatic photo-mosaics produced by digitally stitching together the many overhead photos. We were also able to take many dramatic "beauty shots" covering wide areas of the site from atop 20 foot high mobile tower. In total, we documented over 500 tracks at the Ballroom (about 450 tracks on the main part, and about 90 more on the narrow "Parlor" or "Annex" strip just to the north east). Even more were visible under water at the south end. The vast majority are three-toed footprints made by theropods (bipedal meat-eating dinosaurs), most probably by Acrocanthosaurus. However, some of the elongate "metatarsal" (heel-impressed) tracks may have been made by ornithomimids (slender "ostrich mimic" dinosaurs), possibly while contending with very soft mud, or when lowering their postures while foraging for small food items in the mud and shallow water. Some of the small theropod tracks may either be made by "baby" Acros, or a smaller theropod species. Three trails of sauropod tracks (one adult and two juvenile) were made by long-necked, four-legged, plant-eating dinosaurs informally called "brontosaurs") occur on the main part of the site. The adult tracks are about a yard long and over a foot deep, with huge mud up-pushes around the rims, but do not record digit impressions well. The juvenile sauopod tracks, about 2 feet long, are generally less deep, and a few record all five digits on the rear prints. A few other sauopod tracks occor in the Parlor area. Yet other depressions are of uncertain origin. These include a long "squiggle" trail over 15 feet long, which may have been made by a walking fish similar to modern mud-skippers or lungfish. Others are large holes which may represent places where tracks were chiseled out by locals decades ago. During fairly dry conditions in the summers of 2011 and 2013 I returned to the Ballroom to extend the documentation and photography, and to make flexible rubber molds of some of the most distinct and unusual tracks on the site, including some of the best theropod tracks, and the three best juvenile (youngster) sauropod tracks. (Note that mold-making may only be done by experienced workers with permission of the park). During a severe drought in the summer of 2022 the Ballroom was drier than ever before recorded, but because I and many volunteers were focusing on cleaning and further mapping the long "Lone Ranger Trail" and many trails in the Taylor Site area, we were not able to do much at the Ballroom before rains came and covered the site with over two feet of water. However, during a similar severe drought the next summer (2023), I was able to organize another major track project (including several diligent prior volunteers from the Dallas Paleontological Society and Master Naturalist groups), focusing on the Ballroom Site and several others, resulting in hundreds of new tracks being exposed, cleaned, and documented, including at least 150 new tracks at the Ballroom alone. Although water pools over a foot deep existed at the low parts of this and other sites when our work began in mid August, by mid September the unusually dry conditions and exceptionally high temperatures (often reaching 108-110 F) caused the remaining water at the Ballroom and most other sites to entirely evaporate. At the Ballroom, we were able to not only re-clean most of the previously mapped area of the site (finding over a dozen new "baby" (or small species?) tracks previously overlooked, but also expose, clean, photograph, and film over 100 new new tracks in the lower south and southeast areas of the site, as well as find other new tracks under the fairly deep gravel on the east side of the site. For the first time we were able to do 3D lidar (laser based) imaging and drone filming at the site, which should allow even more precise and complete site maps to be made. In the near future more photos, diagrams, and info will be posted from our 2023 work. More details about the various tracks are features on the site are provided below, with corresponding illustrations found in the menu at left. Large and Deep Sauropod Trackway These large tracks (over three feet long), made by an adult sauropod are attributed to Sauroposeidon (formerly associated with Pleurocoelus and Paluxysaurus). Most of the tracks in the trail are rear footprints, with no indication of the smaller front prints since the dinosaur was (with one exception) stepping on and obliterating his smaller front prints with his larger, more oblong rear prints. In one case, however, a complete front print can be seen in front of the rear print. All of the tracks in this trail are so deeply impressed they lack clear toe marks, but are impressive due to their size and the incredibly high mud "up-pushes" around their margins (some over 18 inches above the bottom). One can almost hear the loud "squish" of each footstep as each foot sank in the soft mud. This single adult sauropod trail heading northeast, and two juvenile sauropod trails nearby (discussed below) heading northwest contrast the parallel, southward progressing sauropod trails at the R.T. Bird and Ozark areas, which were evidently all part of a herd of at least 8 or 9 dinosaurs moving together. The herd may have included even more dinosaurs, which might be seen if one could excavate beyond the river banks. All of the Paluxy river sauropod tracks are are currently attributed to the dinosaur Sauroposeidon proteles, although the associated bones are sparse and fragmentary, so it is unclear (at least to me) whether they are distinct from, or take precedence over, other dinosaur names previously associated with the Paluxy sauropod tracks, including Pleurocoelus and Paluxysaurus. Juvenile Sauropod Trackways Two trails of juvenile (youngster) sauropod trails occur near the adult sauropod trail on the site, both progressing south west. They are the smallest sauropod tracks known in the park. Each rear print is less than two feet long--just over half the size of the adult tracks. Each of these trails proceed for about a dozen steps however most of the individual tracks in each trail are overlapped and distorted by the many theropod tracks stepping in and around them. Most also lack clear toes or front prints, except for three steps close to the bank in the southernmost trail, which are virtually perfect, making them among the best preserved juvenile sauropod tracks in the world. All three rear prints here show all five digits, as well as crescent-shaped remnants of the front footprints. The partial nature of the front prints appears to be due to mud being pushed forward from the rear prints, and possible partial overlap of indistinct theropod tracks. Whereas adult sauropod prints (when clear) typically show three large, sharp claw marks on the inside of the foot, and two smaller, blunter digit marks at the outside, these distinct juvenile sauropod tracks show five clear toe marks all about the same size and shape - suggesting that the first three digits and claws on sauropods grew larger as the animal aged, while the last (outer) two relatively small and blunt. The juvenile tracks also appear to show a raised area in the middle of the prints that is more pronounced than on adult sauropod tracks, suggesting that in juveniles there was either a significant "arch" in the foot, or reflecting a rocking motion between the heel and toe parts of the print. Note that both juvenile trails are moving in the opposite direction from the adult sauropod, with nearby theropod tracks going in many other directions. This suggests that the theropods here (and most other sites, as discussed elsewhere) were not actively pursuing the sauropods, but instead probably feeding on smaller creatures (fish, crustaceans, amphibians, mollusks, whose fossils are found in nearby beds) in the mud and shallow water, which probably would be easier and safer to catch than bringing down a sauropod. After all, even a small sauropod could kill or main a theropod with one swipe of its massive tail. For their part, the sauropods may have been feeding on water plants, whose fossils are also sometimes found in nearby rocks. Theropod Tracks Several hundred theropod tracks occur on the site, many in striding trails. Like many other three-toed, sharp-clawed tracks in the Paluxy, most were probably made by Acrocanthosaurus, a two legged, predatory dinosaur that resembled Allosaurus, but had a raised ridge on its back. Most of the tracks are made by individuals only to 1/2 to 3/4 the size of a full grown Acrocanthosaurus (which could get almost as large as a T. rex). Some even smaller tracks at the site only 6 to 10 inches long were probably made by juvenile "Acros" but some could be made my a small theropod species. Indeed, several previously unmapped small tracks that I found on the site in 2023, show digits held closer together than a typical Acro track, even other small ones. Some show only two digits, leading to speculations that perhaps they were made by a "raptor" type dinosaur impressing only two toes; however, this seems unlikely, since some in line with them show indications of three toes, and it's not unusual for one or two digits to impress more distinctly than the others. Most of the theropod tracks at the Ballroom show varying degrees of mud-collapse, where the very soft limy mud slumped back into one or more of the toe impressions. This often causes the prints to appear smaller than the foot actually was; however, if one looks closely one can usually see the slits indicating where the originally longer digit impressions occurred, and/or prints in the same trail with more distinct and complete toe impressions. Mud-collasped theropod tracks whose digits appear smaller or bunter than usual, have also sometimes been mistaken for ornithopod tracks (made by bipedal plant eathing dinosaurs) here and elsewhere, but again, the traces of the longer and sharper digits are always discernable on closer inspection. No convincin Others are shallower and more distinct, especially on the south end of the site, suggesting that the mud was firmer when these dinosaurs walked (perhaps days after the others). It's also possible that even at any point in time, some parts of the site were more dry and firm than other parts. Metatarsal Tracks As on other Paluxy sites such as the Taylor Site and Denio Branch site (site 4), the Ballroom contains several trails which include "metatarsal tracks". These were made by dinosaurs that sometimes impressed their metatarsi (soles and heels) as they walked. The reason for this behavior is unclear, but might have occurred when the dinosaurs crouched down while foraging for small prey in the mud or shallow water. This would not be surprising, since they had a veritable "sea food" buffet to enjoy, as indicated by the abundant and diverse fossils found in the layers surrounding the track beds, including snails, clams, oysters, worm and crustacean burrows, fish teeth, and occasionally remains of other creatures as well. Comparisons of footprint proportions with dinosaur foot bones suggest that many of these metatarsal prints were made by a relatively slender, fleet-footed dinosaur, probably an ornithomimid ("ostrich mimic") or basal coelurosaur. Problematic "Squiggles" In the northwest area of the site is a long sequence of connected irregular depressions, making a trail over fifteen feet long, which have been informally referred to as "squiggle marks." The creature made these unusual traces is uncertain, and was originally speculated to be some sort of large invertebrate, but upon further study in 2023 (at which time a mold was made of the entire trail and nearby theropod tracks, I believe it was more likely made by a walking fish similar to a mud-skipper or lungfish, whose trails it resembles. Supporting this hypothesis are repeating sharp-ended protrusions along the outside of the trail that appear consistent with fins but not feet of either vertebrates or invertebrates. Most interestingly, a dinosaur walking perpendicular to the squiggle trail in the usual digitigrade (toe-walking) fashion drops to its heels, making a metatarsal print close to where the squiggle trail ends, suggesting that the dinosaur enjoyed a squiggle-creature snack. This coincides with the above proposal that at least some metatarsal tracks may have been made by dinosaurs lowering their postures as they foraged for food items in the mud and shallow water.