Hubbry Logo
GrallatorGrallatorMain
Open search
Grallator
Community hub
Grallator
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Grallator
Grallator
Grallator
View on Wikipedia
from Wikipedia

Grallator
Temporal range: Early Triassic-Early Cretaceous
~250–100 Ma
Typical footprint form
Trace fossil classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Ichnofamily: †Grallatoridae
Ichnogenus: †Grallator
Hitchcock, 1858
Type ichnospecies
†Grallator cursorius
Hitchcock, 1858
Ichnospecies

Many, see text

Synonyms
  • Hunanpus

Grallator (GRA-lə-tor) is an ichnogenus (form taxon based on footprints) which covers a common type of small, three-toed print made by a variety of bipedal theropod dinosaurs. Grallator-type footprints have been found in formations dating from the Early Triassic through to the early Cretaceous periods. They are found in the United States, Canada, Europe, India, Australia, Brazil (Sousa and Santa Maria Formations) and China,[1] but are most abundant on the east coast of North America, especially the Triassic and Early Jurassic formations of the northern part of the Newark Supergroup.[2][3] The name Grallator translates into "stilt walker", although the actual length and form of the trackmaking legs varied by species, usually unidentified. The related term "Grallae" is an ancient name for the presumed group of long-legged wading birds, such as storks and herons. These footprints were given this name by their discoverer, Edward Hitchcock, in 1858.[2]

Grallator footprints are characteristically three-toed (tridactyl) and range from 10 to 20 centimeters (or 4 to 8 inches) long. Though the tracks show only three toes, the trackmakers likely had between four and five toes on their feet. While it is usually impossible to match these prints with the exact dinosaur species that left them, it is sometimes possible to narrow down potential trackmakers by comparing the proportions in individual Grallator ichnospecies with known dinosaurs of the same formation. For example, Grallator tracks identified from the Yixian Formation may have been left by Caudipteryx.[3]

Species

[edit]
Grallator toscanus from Monte Pisano (Italy)

Source:[4]

Paleopathology

[edit]

Fossil tracks can be informative about theropod pathologies but apparently pathological traits may be due to unusual behaviors. Sandstone stratum dating to the Norian in southern Wales preserves tracks of an individual with a deformed digit III attributed to the ichnogenus Anchisauripus. The distal end of the digit was consistently flexed. However, this apparent pathology could be caused by the animal rotating the tip of that digit when lifting the foot.[6]

Occurrences

[edit]

Grallator-type footprints have been found in formations dating from the Early Triassic through to the early Cretaceous periods. They are found in the United States, Canada, Europe, Australia, Brazil (Sousa and Santa Maria Formations) and China,[1] but are most abundant on the east coast of North America, especially the Triassic and Early Jurassic formations of the northern part of the Newark Supergroup.[2][3]

Newark Supergroup tracks

[edit]
Negative footprint of G. cuneatus showing skin impressions

The most famous, and archetypal tracks that conform to the Grallator type are those found on the East Coast of North America, specifically from the Late Triassic to Early Jurassic Newark Supergroup. These footprints were likely made by an unidentified, primitive dinosaur similar to Coelophysis.[2] The Newark Supergroup footprints show digits II, III and IV, but no trace of the shorter digits I and V which would likely have been present in a dinosaur of this stage. The outer two digits would have been stubby and ineffective, not touching the ground during walking or running.[2] Despite losing most of their effectiveness, dinosaur evolution had not yet removed these digits to fully streamline the foot. This is known because rare specimens are found with traces of these outer digits. Digits II, III and IV have 3, 4 and 5 phalanges respectively, giving Grallator a ?-3-4-5-? digital formula.

Although the Newark Supergroup Grallator tracks were made by a bipedal saurischian dinosaur, they can easily be mistaken for those of the late Triassic ichnogenus Atreipus.[7] The trackmaker of Atreipus prints was a quadrupedal ornithischian. The reason for this similarity is a lack of divergence in the foot evolution of the two distinct groups of dinosaurs: ornithischians and saurischians.

Eubrontes (= Grallator) in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah.

Wales

[edit]

In January 2021, while walking with her father Richard Wilder, a four-year-old girl called Lily Wilder found a 215- to 220-million year-old dinosaur footprint at Bendricks Bay in the Vale of Glamorgan, Wales.[8][9][10]

Experts believe that the footprint was most likely left by a dinosaur (grallator) that stood about 75 centimeters (29.5 inches) tall and 2.5 meters (about 8 feet) long and walked on its two hind feet.[11][12]

The scientists called the girl's discovery "the finest impression of a 215 million-year-old dinosaur print found in Britain in a decade".[8] Karl-James Langford of Archaeology Cymru considered the find to be "internationally important".[8][13] Cindy Howells, a palaeontologist at Amgueddfa Cymru – National Museum Wales, described it as "one of the best-preserved examples from anywhere in the UK" and said that it "will really aid palaeontologists to get a better idea about how these early dinosaurs walked".[10]

Slovakia

[edit]

In the 70s, in Tichá Dolina (English: Silent Valley) two paleontologists found tracks from the late triassic and named them "Coelurosaurichnus Tatricus" but later it was renamed as "Eubrontes Tatricus" (Eubrontes is probably a synonym of Grallator) and size estimates suggest it was made by a smaller carnivorous theropod, with indirect evidence suggesting it was Liliensternus, but we do not know for sure. [14]

See also

[edit]

References

[edit]

Further reading

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Grallator

View on Grokipedia
from Grokipedia
Grallator is an ichnogenus comprising a common type of small, three-toed (tridactyl) footprints attributed to bipedal theropod dinosaurs, typically measuring 5–15 cm in length and characterized by narrow, elongate impressions with a digit formula of 2-3-4 phalanges. These tracks, indicating fast-moving animals with an erect posture and long strides, were first named in 1858 by Edward Hitchcock, who drew inspiration from the wading birds of the Grallae group due to their slender, bird-like appearance. Etymologically derived from Latin meaning "one who goes on stilts," Grallator reflects the trackways' narrow gauge and extended steps, often preserved in fine-grained mudstones of the in the Valley. The ichnogenus encompasses multiple , such as G. cursorius, G. parallelus, and G. tenuis, based on variations in trackway patterns and individual print morphology, though it likely represents tracks from a variety of small theropods rather than a single . occurrences span the to (approximately 237–130 million years ago), with notable sites in (e.g., and ), (e.g., Spain's region), (e.g., Queensland's Mt. Morgan and Colliery, dating to ~220 million years ago), and (e.g., , including a January 2025 discovery of tracks in Province). In , Grallator footprints provide some of the earliest evidence of dinosaurs on the continent, varying in size from 4–18 cm (with outliers up to 28 cm), and are distinguished from larger tracks possibly by subadult individuals of similar theropods. Paleontologically, Grallator is significant for illuminating theropod diversity, locomotion, and behavior during the early to middle , as the tracks reveal agile, bipedal predators or omnivores—potentially including taxa like or juveniles of larger forms—navigating fluvial and lacustrine environments. Specimens, often undertracks or direct imprints in sedimentary layers, contribute to reconstructions of ecosystems and have been studied since the , with collections housed at institutions like Amherst College's Pratt . Ongoing discoveries worldwide, including recent finds in as of 2025, underscore Grallator's ubiquity as one of the most abundant early trace fossils, aiding in and evolutionary inferences without relying on skeletal remains.

Description

Track Morphology

Grallator tracks are characterized by a tridactyl structure, featuring elongated impressions of digits II, III, and IV, with the absence of digit I (hallux) impressions in the majority of specimens. This configuration reflects a narrow, gracile pes morphology suited to bipedal theropod locomotion, where the central digit III is the longest and most prominent, often comprising about 55-60% of the total foot length. The digits are slender and slightly divergent, with a total divarication angle between digits II and IV typically ranging from 10° to 30°. Distinct claw marks are frequently preserved at the acuminate tips of the digits, particularly in well-preserved examples, indicating sharp, curved s typical of theropod trackmakers. Subtle impressions of digital pads may also appear, corresponding to the phalangeal structure, though these are often faint due to substrate variations and preservation quality. The overall outline is narrow and elongated, with a length-to-width ratio often exceeding 1.5, emphasizing the lightweight, agile nature of the foot. In trackways, Grallator impressions exhibit an alternating step pattern consistent with bipedal progression, featuring pace angulations of approximately 160-170 degrees, with the pes oriented nearly parallel (0-10 degrees) to the direction of travel, and stride lengths that vary depending on substrate consistency and locomotor speed. These patterns produce narrow-gauge trackways. Grallator tracks occur abundantly in sediments worldwide, particularly in formations. While sharing superficial similarities with modern bird tracks—such as the tridactyl form and occasional pad-like impressions—Grallator is distinguished by theropod-specific proportions, including the pronounced elongation of digit III and lack of a reversed hallux, which underscore its reptilian affinities rather than avian ones. This morphology highlights adaptations for terrestrial predation and agility in early theropods.

Size and Variations

Grallator footprints are typically small to medium in , with lengths ranging from 7 to 21.5 cm and widths of 3.5 to 9.9 cm, yielding a footprint length-to-width of 1.73 to 2.5. These dimensions correspond to trackmakers with estimated hip heights of approximately 0.3 to 0.9 m, calculated using the standard theropod of hip height equaling four times the length. Variations in footprint size are evident, with smaller forms under 10 cm likely representing juvenile individuals and larger examples reaching up to 25 cm, potentially reflecting ontogenetic growth stages or distinct morphotypes within the ichnogenus. differences accompany these size variations; smaller s exhibit greater projection of digit III and narrower interdigital angles, while larger ones show proportionally wider forms and increased divarication, consistent with allometric scaling. Substrate conditions influence morphology, with impressions in soft producing broader, more distorted outlines compared to the sharper details preserved in firmer sandstones or as natural casts. Key metric ratios include a divarication between digits II and IV of 10 to 30 degrees in well-preserved examples, though preservation can elevate this to 32 to 55 degrees. Trackway patterns typically display a pace-to-stride of approximately 1:2, indicative of a bipedal .

History and Classification

Discovery and Naming

The fossil tracks now assigned to the ichnogenus Grallator were first systematically described and named by Edward Hitchcock, a and president of , in his 1858 publication Ichnology of New England: A Report on the Sandstone of the Connecticut Valley, Especially Its Fossil Footmarks. These tracks, preserved in Late Triassic to Early Jurassic sandstone formations in , , were collected from sites in the Valley and initially interpreted by Hitchcock as evidence of large, ancient birds due to their three-toed morphology and slender form. Hitchcock coined the name Grallator from the Latin grallator, meaning "stilt walker," alluding to the tracks' elongated, wading appearance reminiscent of long-legged shorebirds in the group Grallae. This reflected his avian , as the prints suggested agile, bipedal creatures with narrow toes suitable for marshy environments. Collections of these tracks began in the early amid quarrying operations in the , where —a reddish-brown prized for building—was extracted for use in construction projects across . Hitchcock, prompted by initial discoveries reported in the , amassed what became the world's largest collection of such fossils at the time, cataloging over 10,000 individual footprints across more than 1,100 slabs housed at . His efforts, supported by state funding, involved documenting specimens from multiple quarry sites to understand their geological and biological significance. By the late , following the discovery of bipedal dinosaur skeletons, such as the sauropodomorph in the same region in 1855 and subsequent bipedal theropod finds in , the interpretation of Grallator tracks shifted from avian to reptilian origins. Paleontologists, including , recognized the parallels between the tracks' morphology and the anatomy of early theropods, solidifying their attribution to dinosaurs by the 1870s despite Hitchcock's lifelong adherence to the bird theory until his death in 1864.

Ichnotaxonomy

Grallator is classified within the ichnofamily Grallatoridae, established by Lull in 1904, which encompasses small to medium-sized theropod tracks characterized by narrow, elongate tridactyl pes impressions with reduced digital pads and minimal divarication angles, distinguishing them from broader-toed forms such as those in the ichnofamily Eubrontidae (e.g., ). This family placement emphasizes the slender morphology typical of early theropod trackmakers, with Grallator representing the smallest and most gracile end of the spectrum. The ichnogenus was originally named by Hitchcock in 1858 and formally defined by Lull in 1904 based on criteria highlighting tridactyl footprints lacking a prominent hallux impression, with digits II-IV subequal in length, a narrow heel region, and overall impressions measuring 5-20 cm in length. Lull's diagnosis focused on the absence of a reversed hallux and the presence of sharp, clawed digit tips, criteria that have guided subsequent ichnotaxonomic assignments despite variations in preservation. Several proposed synonyms for Grallator have been evaluated through morphological comparisons, particularly in Asian track assemblages; for instance, Hunanpus, described from sites in , was resolved as a junior in the 1980s via detailed pedal shape analysis showing indistinguishable narrow-toed tridactyly and stride patterns. Ichnotaxonomic debates surrounding Grallator center on lumping versus splitting approaches, with some researchers advocating consolidation of similar narrow-toed forms under Grallator to avoid over-subdivision based on minor preservational differences, while others reassign broader or more divergent variants to related ichnogenera like Atreipus, which exhibits greater digital splay and occasional manus traces. These discussions underscore the challenges of distinguishing substrate-induced distortions from true morphological variation in early theropod tracks.

Ichnospecies

Type Ichnospecies

Grallator cursorius, established by Edward Hitchcock in 1858, serves as the type ichnospecies of the ichnogenus Grallator and is based on fossil tracks from the Portland Formation near . Hitchcock originally interpreted these as traces of ancient birds, naming the ichnospecies to evoke a "running " based on the trackway's narrow gauge and implied speed. The emended diagnosis of G. cursorius defines it as small (less than 15 cm long), bipedal, functionally tridactyl ichnites exhibiting the following combined features: digit III projects farther anteriorly than digits II and IV; the footprint's length-to-width is at least 2; divarication between digits II–III and III–IV measures 10°–30°; digits are long, straight, and tapering with pointed distal ends and prominent marks; digits II and IV are subequal in length; no hallux or metatarsal pad impressions are present; trackways are narrow with pace angulation of 160°–170°, pes stride-to-pes length s of 4–6, and pes pace-to-pes length s of 2–3.5. This emphasizes acute interdigital angles and slender digits, distinguishing it from broader or larger theropod tracks. The consists of a natural cast preserving four successive pes impressions from a single trackway on slab AC 4/1a (formerly numbered 234) in the collections; it was collected in 1847 by Pliny Moody from his farm in South Hadley, Massachusetts, and measures approximately 8 cm in footprint length with a length-to-width of about 2.2. A (AC 23/2) consists of tracks from a second individual collected from the Turners Falls Formation in . In 1980, Paul E. Olsen proposed combining Grallator with related ichnogenera like Anchisauripus and due to observed morphologic overlap, but subsequent work in by Olsen and colleagues refined the diagnosis of G. cursorius to focus exclusively on smaller variants under 15 cm, excluding larger forms to maintain ichnotaxonomic distinctiveness. Grallator cursorius is the nominal species of the ichnofamily Grallatoridae.

Additional Ichnospecies

Several additional ichnospecies have been assigned to Grallator, though their validity has been debated in subsequent taxonomic revisions due to overlapping morphologies with the type species G. cursorius. G. parallelus (Hitchcock, 1865) is recognized as a junior of G. cursorius. One such ichnospecies is Grallator toscanus, originally described as Coelurosaurichnus toscanus by Huene in 1941 from tridactyl tracks in the Upper Quarziti del Monte Serra Formation at Monte Pisano, , . This ichnospecies features a tridactyl pes with mesaxonic structure, but poor preservation limits detailed comparisons; it was later synonymized with Grallator as a junior by Leonardi and Lockley in 1995, emphasizing its placement within the Grallator-Atreipus plexus. In , Grallator emeiensis (Zhen et al., 1994) represents a diminutive form from the Lower Cretaceous of Province, , with tracks approximately 2 cm long, characterized by very slender digits, short parasagittal digits II and IV, and fine claw impressions. These features distinguish it from larger Grallator forms, though narrower stride lengths are inferred from the small trackmaker size rather than direct measurements. Similarly, Grallator tenuis (Hitchcock, 1858), known from small (about 5.5 cm long) tridactyl tracks with digit length ratios where III exceeds II, exhibits narrow, elongate digits and subtle claw details, originally from the Early of but reported in Asian contexts like the Lower Thaiat Member. Taxonomic revisions in the 1990s, such as those by Lockley et al. (1995), addressed synonymies among Grallator ichnospecies due to morphological overlap; for instance, Grallator sulcatus (originally named by Baird) was reassigned to Atreipus sulcatus based on shared narrow trackway patterns and divarication angles around 30–35° and is considered a distinct . Morphological distinctions among valid additional ichnospecies often include variations in digit divarication, with G. toscanus showing angles of approximately 25–35° compared to about 30° in the type species, reflecting subtle preservational or substrate influences.

Paleoecology

Trackmaker Interpretations

Grallator tracks are widely attributed to small basal theropods, particularly coelophysoids such as , whose pedal skeletons exhibit narrow, elongate metatarsals that align closely with the slender, subparallel digit impressions characteristic of these ichnites. Comparative analyses of foot morphology, including the reduced first digit and prominent claw marks on digits II–IV, further support this assignment, as these features produce tridactyl prints with low divarication angles (typically 10–30°) and a length-to-width exceeding 2. Similarly, (formerly Syntarsus) has been identified as a likely trackmaker for certain Grallator trackways, based on matching skeletal proportions and the prevalence of coelophysoid body fossils in coeval strata. The estimated size of Grallator trackmakers, derived from scaling footprint dimensions (typically 10–20 cm long) to theropod skeletal ratios, suggests bipedal animals approximately 1–2 meters in total length and weighing 10–30 kg. This corresponds to juvenile or small adult coelophysoids, with hip heights of 40–80 cm inferred from pes length multiples, consistent with the agile, lightweight build of early theropods. Interpretations exclude ornithischians as trackmakers due to mismatches in digit configuration and ; while some bipedal ornithischians produce tridactyl prints, their broader angles (>40°) and wider gauge trackways differ from the narrow, mesaxonic morphology of Grallator. Crocodylomorphs are similarly ruled out, as their semi-aquatic or quadrupedal locomotion yields prints with distinct phalangeal pads and higher digit divarication, unlike the strictly bipedal, digit-focused impressions of Grallator. Although Grallator prints share morphological similarities with those of small deinonychosaurs—such as slender digits and subequal impressions—these analogies are limited by temporal constraints, as deinonychosaurs did not appear until the , postdating most Grallator occurrences by tens of millions of years.

Behavioral Inferences

Grallator trackways exhibit a bipedal characterized by alternating pes impressions, with relative stride lengths (stride divided by hip height) typically ranging from 1.5 to 3.0, indicating walking to slow running locomotion. Using (1976) for estimating speed from trackway parameters—where velocity v=0.25g0.5S1.67H−1.17v = 0.25 g^{0.5} S^{1.67} H^{-1.17} (with gg as , SS as stride length, and HH as hip height)—speeds for Grallator trackmakers are calculated at 5–15 km/h across various sites, reflecting typical foraging paces for small theropods. Hip height is estimated as approximately four times foot length for these bipedal forms. Trackway patterns in Grallator impressions often show straight-line progression over distances of several meters, with occasional subtle turns or meanders suggesting directed movement consistent with or seasonal migration along lacustrine margins. Rare instances of parallel trackways, particularly among smaller impressions attributed to juveniles, imply possible gregarious behavior in groups traveling in the same direction with uniform spacing. Deeper pes impressions in wet, fine-grained sediments, such as micaceous sandstones, indicate interactions with soft substrates where trackmakers likely adopted cautious, deliberate steps to avoid excessive sinking, as evidenced by distorted outlines and undertracks in lacustrine deposits.

Paleopathology

Documented Cases

No well-documented cases of pathology specifically in Grallator tracks have been reported. Pathological features are exceptionally rare in Grallator tracks, comprising less than 1% of documented specimens, in contrast to higher incidences (up to 21% in some assemblages) observed in tracks of larger ichnogenera such as tyrannosaurids.

Occurrences

North American Sites

Grallator tracks are most abundantly preserved in the of eastern , spanning the to in rift basin environments across basins such as Newark, , Fundy, and Gettysburg. These occurrences, dating from approximately 230 to 200 Ma, include thousands of small theropod footprints attributed to Coelophysis-like dinosaurs, particularly in formations like the Stockton, Passaic, and Portland, where they appear in fluvial floodplains and lacustrine margins. In the Hartford Basin of and , notable sites include those in the East Berlin and Portland Formations near Holyoke, where Grallator-dominated assemblages preserve dense concentrations of tridactyl tracks up to 15 cm long, often alongside indicating shallow lake or deposition. The in Holyoke exemplifies these, with exposed slabs yielding dozens of well-preserved Grallator tracks from sediments. Further south in the Newark Basin of , Grallator occurs in the Towaco and Boonton Formations, where trackways extend for tens of meters across red surfaces, reflecting theropod locomotion in arid settings during the . In the southwestern United States, Grallator is documented in the Norian-age Chinle Group, particularly the Redonda Formation of east-central , including sites at Mesa Redonda and Apache Canyon. These yield Grallator-dominated ichnofaunas with tracks averaging 8 cm in pes length, mixed with non-dinosaurian forms like Brachychirotherium and Rhynchosauroides in playa lake and fluvial contexts. Additional Chinle occurrences, such as Grallator tracksites along Highway 191 in , feature monospecific assemblages preserved as natural casts on fallen slabs.

European Sites

Grallator tracks in Europe are documented from to deposits, primarily in coastal and insular paleoenvironments that reflect the fragmented of during these periods. These occurrences provide insights into the early diversification and dispersal of small theropod dinosaurs across what were then isolated landmasses and archipelagos in the Tethys region. In southern , Grallator tracks are preserved in the (~220 Ma) mudstones and sandstones exposed at Bendricks Bay near Barry, part of the Mercia Mudstone Group. This site features multiple trackways attributed to small bipedal theropods, with footprints typically 10-15 cm long, indicating trackmakers around 1-2 m in length. A notable discovery at the site involved a well-preserved 11 cm Grallator print found by four-year-old Lily Wilder, highlighting the accessibility of these coastal sediments for ongoing finds. The Bendricks locality underscores the presence of early theropods in a subtropical setting along the eastern margin of the Pangaean supercontinent. In northern , , the Monte Pisano region yields some of the earliest known Grallator tracks from the Upper (, ~230 Ma) Verrucano Group continental deposits. These include the ichnospecies G. toscanus (originally described as Coelurosaurichnus toscanus), represented by tridactyl prints about 12 cm long in red sandstones and conglomerates associated with carbonate platforms. The tracks suggest small theropods navigating alluvial and lacustrine environments on the Adria microplate, marking one of the oldest records in and contributing to understanding theropod radiation in peri-Tethyan islands. Late Triassic (~late Norian-Rhaetian, ~210 Ma) Grallator-like tracks from the in , within the Tomanová Formation sandstones, were initially classified under Coelurosaurichnus tatricus but later reassigned to tatricus due to their larger size (up to 25 cm). These tridactyl impressions, found on slab surfaces in a fluvial-deltaic setting, likely record a medium-sized theropod comparable to Liliensternus, reflecting theropod activity in a rift basin along the northern Tethys margin. The site's ichnofauna highlights faunal connections between central European highlands and broader Pangaean theropod distributions. In northern Spain's region, Grallator tracks occur in (Kimmeridgian-Tithonian, ~155-145 Ma) tidal flat deposits of the Lastres Formation along the "Dinosaur Coast." Over 20 specimens, including natural casts 8-15 cm long, have been documented from multiple megatracksites, indicating small theropods traversing intertidal zones. These occurrences, part of extensive coastal track assemblages, suggest migratory behaviors along Jurassic island chains in the Hispanic Corridor, linking Iberian and European theropod populations.

Other Global Sites

Grallator tracks have been reported from several sites in , particularly in the of , where the ichnospecies G. emeiensis occurs in the Lower Jiaguan Formation. These tracks, measuring approximately 2-3 cm in length, are preserved in purple-red sandstones and mudstones indicative of fluvial-lacustrine environments, often co-occurring with other small theropod ichnotaxa such as Minisauripus chuanzhuensis and Velociraptorichnus sichuanensis. The Jiaguan Formation, dated to the Aptian-Albian stages (circa 125-100 Ma), represents one of the youngest records of diminutive Grallator-type footprints in , suggesting persistence of small-bodied theropod trackmakers in floodplain settings. In January 2025, a new track assemblage of Grallator ssatoi was announced from the Lower (~110 Ma) strata in Wulan town, Jingyuan county, Province, northwest , featuring carnivorous footprints discovered by researchers, adding to the record of small theropod activity in the region. In , Grallator-like tracks are rare within the (Valanginian-Barremian) Broome Sandstone of the Dampier Peninsula, , where they form a minor component of predominantly sauropod- and ornithopod-dominated ichnofaunas. These small tridactyl impressions, typically under 10 cm long, have been noted at coastal tracksites but remain debated, with some interpretations suggesting they may represent reworked material from older or deposits transported into the strata. The Broome Sandstone's intertidal to supratidal , dated to approximately 130-125 Ma, highlights the sporadic nature of small theropod activity amid larger assemblages in Gondwanan settings. Occurrences in South America include tentative assignments of Grallator ichnospecies in the (Carnian) Santa Maria Formation of , , associated with early dinosaurian faunas including herrerasaurids and other basal saurischians. These tridactyl tracks, preserved in mudstones and sandstones of aeolian-fluvial origin, measure 5-8 cm and are interpreted as undertracks from small bipedal theropods navigating semi-arid paleoenvironments around 233-227 Ma. Such finds underscore Grallator's role in documenting the initial diversification of theropod dinosaurs in western . Collectively, these global sites illustrate the temporal and geographic breadth of Grallator, spanning from the (approximately 230 Ma) to the (approximately 100 Ma), reflecting the widespread distribution of small, bipedal theropods across Pangea and its fragments. This cosmopolitan pattern implies ecological adaptability among early theropod lineages, with tracks often preserved in marginal marine to continental deposits.

References

  1. https://www.wesleyan.edu/ees/museum/footprints_CT_MA.html
  2. https://www.australianageofdinosaurs.com/page/108/australian-age-of-dinosaurs-grallator
  3. https://www.globaltimes.cn/page/202501/1326360.shtml
  4. https://www.scup.com/doi/full/10.1111/j.1502-3931.2011.00276.x
  5. https://www.sciencedirect.com/science/article/pii/S0031018225005978
  6. https://turia.uv.es/index.php/sjpalaeontology/article/download/17156/15379/56012
  7. https://peerj.com/articles/11788.pdf
  8. https://www.researchgate.net/figure/dealized-Grallator-track-from-a-right-foot-with-pedal-skeleton-superimposed-The-digital_fig1_227924849
  9. https://onlinelibrary.wiley.com/doi/10.1111/pala.12132
  10. https://www.researchgate.net/figure/Details-of-the-Grallator-trackway-in-the-lower-Clarens-Formation-at-the-Storm-Shelter_fig4_350467791
  11. https://palaeo-electronica.org/content/2015/1166-langenberg-tracks
  12. https://onlinelibrary.wiley.com/doi/10.1111/pala.12449
  13. https://www.researchgate.net/figure/comparison-between-the-representative-Grallator-like-ichnites-of-trackways-a-B-and-c-at_fig7_312285782
  14. https://doi.org/10.7203/sjp.31.2.17156
  15. https://www.ldeo.columbia.edu/~polsen/nbcp/olsen_et_al_98_eubrontes.pdf
  16. https://www.researchgate.net/publication/336874519_Shape_variability_in_tridactyl_dinosaur_footprints_the_significance_of_size_and_function
  17. https://peerj.com/articles/11788/
  18. https://www.scup.com/doi/10.1111/j.1502-3931.2011.00276.x
  19. https://books.google.com/books?id=HvpaAAAAQAAJ
  20. https://www.smithsonianmag.com/science-nature/hitchcocks-primeval-birds-9861470/
  21. https://www.journals.uchicago.edu/doi/10.1086/523121
  22. https://www.amherst.edu/museums/naturalhistory/collections/ichnology
  23. https://www.atlasobscura.com/articles/edward-hitchcock-dinosaur-fossils-footprints-birds-amherst
  24. https://www.sciencedirect.com/science/article/abs/pii/S0195667118303732
  25. https://www.ldeo.columbia.edu/~polsen/nbcp/pangea2_ols.rain.19.314_368.pdf
  26. https://pmc.ncbi.nlm.nih.gov/articles/PMC8500084/
  27. https://archive.org/download/biostor-859/biostor-859.pdf
  28. http://www.xinglida.net/pdf/Lockley_2013_China_ichnotaxonomy.pdf
  29. https://doc.rero.ch/record/15469/files/PAL_E2856.pdf
  30. https://open.uct.ac.za/server/api/core/bitstreams/5b58e5d3-9fef-4825-921d-b6d537c0b025/content
  31. https://gsa.confex.com/gsa/2004NE/webprogram/Paper70257.html
  32. https://www.italianjournalofgeosciences.it/fulltext/1231/early-evolution-of-dinosaurs-indications-from-the-triassic-footprint-record.pdf
  33. https://www.researchgate.net/publication/296348065_A_PROPOSAL_TO_ABANDON_THE_ICHNOGENUS_COELUROSAURICHNUS_HUENE_1941-A_JUNIOR_SYNONYM_OF_GRALLATOR_E_HITCHCOCK_1858
  34. https://doi.org/10.1080/10420940.1995.10036507
  35. https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=121366
  36. https://vjs.pgi.gov.pl/article/download/26624/18333/40035
  37. https://www.mindat.org/taxon-P64081.html
  38. https://treatment.plazi.org/GgServer/html/813387CADE1A7C1CFC9194BCD8FDF999
  39. http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532021000300019
  40. http://www.xinglida.net/pdf/Xing%2520Harris%25202009%2520-%2520Grallator%2520isp%2520from%2520Yixian%2520Formation.pdf
  41. https://www.nps.gov/zion/learn/nature/another-kind-of-bigfoot.htm
  42. https://www.sciencedirect.com/science/article/abs/pii/S0031018217308076
  43. https://www.researchgate.net/publication/290484286_The_earliest_known_deinonychosaur_tracks_from_the_Jurassic-Cretaceous_boundary_in_Hebei_Province_China
  44. https://www.tandfonline.com/doi/full/10.1080/08912963.2022.2117042
  45. https://dep.nj.gov/wp-content/uploads/njgws/enviroed/infocirc/dinotrack.pdf
  46. https://www.researchgate.net/publication/264159930_WERE_EARLY_JURASSIC_DINOSAURS_GREGARIOUS_REEXAMINING_THE_EVIDENCE_FROM_DINOSAUR_FOOTPRINT_RESERVATION_IN_HOLYOKE_MASSACHUSETTS
  47. http://www.xinglida.net/pdf/McCrea%20et%20al%202015%20Vertebrate%20Ichnopathology.pdf
  48. https://www.ldeo.columbia.edu/~polsen/nbcp/olsen_88.pdf
  49. https://rainbow.ldeo.columbia.edu/courses/v1001/10.html
  50. https://www.researchgate.net/publication/326804212_The_fish_trail_Undichna_from_playa_lake_deposits_of_the_Early_Jurassic_East_Berlin_Formation_Holyoke_Massachusetts
  51. https://www.academia.edu/934399/Excavated_and_In_Situ_Dinosaur_Footprints_from_the_Murray_Quarry_Early_Jurassic_East_Berlin_Formation_Holyoke_Massachusetts_USA
  52. http://digsfossils.com/fossils/footprints_nj_boonton.html
  53. https://libres.uncg.edu/ir/asu/f/Heckert_A_2000_17_Occurance.pdf
  54. https://www.researchgate.net/publication/257364270_Tetrapod_track_assemblage_of_the_Redonda_Formation_Upper_Triassic_Chinle_Group_in_east-central_New_Mexico_-_re-evaluation_of_ichnofaunal_diversity_from_studies_of_new_material
  55. https://bibliotekanauki.pl/articles/2059243
  56. https://bioone.org/journals/acta-palaeontologica-polonica/volume-56/issue-2/app.2010.0027/A-Late-Triassic-Dinosaur-Dominated-Ichnofauna-from-the-Tomanov%25C3%25A1-Formation/10.4202/app.2010.0027.full
  57. https://museum.wales/news/1209/New-dinosaur-footprint-discovered-on-south-Wales-beach/
  58. https://www.geolsoc.org.uk/science-and-policy/100-great-geosites/educational/dinosaur-footprints-bendrick-rock/
  59. http://www.stsn.it/AttiA2014/02_COLLARETA.pdf
  60. https://www.app.pan.pl/archive/published/app56/app20100027.pdf
  61. https://doc.rero.ch/record/14883/files/PAL_E2023.pdf
  62. https://www.tandfonline.com/doi/full/10.1080/02724634.2016.1269539
  63. https://www.researchgate.net/publication/281400176_Biostratigraphy_of_southern_Brazilian_Middle-Upper_Triassic
  64. https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=121366&is_real_user=1
Add your contribution
Related Hubs
User Avatar
No comments yet.