''Farlowichnus'' is an

ichnogenus An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxon'' comes from the Ancient Greek (''íchnos'') meaning "track" and English , itself derived from ...

of small

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

dinosaur footprint. It includes a single species, ''F. rapidus'', known from prints found in the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

Botucatu Formation of Brazil. ''Farlowichnus'' is known from several fossil trackways that indicate that it was likely a

cursorial A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. cheetah) or if it can keep a constant speed for a long distance (high endurance). "Cursorial" is often ...

animal that was well-adapted to desert environments.

Discovery and naming

The ''Farlowichnus'' fossil material was discovered in sediments of the Botucatu Formation (São Bento Quarry) near

Araraquara Araraquara ( ) is a city in the state of São Paulo (state), São Paulo in Brazil. The population is 250,314 (2022 est.) in an area of . It is also known as "the abode of the sun," because of its impressive sunset and because of its hot atmospher ...

São Paulo São Paulo (; ; Portuguese for 'Paul the Apostle, Saint Paul') is the capital of the São Paulo (state), state of São Paulo, as well as the List of cities in Brazil by population, most populous city in Brazil, the List of largest cities in the ...

, Brazil. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, LPP-IC-0200, consists of a slab with four footprints forming a trackway. Two

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype (biology), isotype ...

s that preserve similar footprints were also assigned, consisting of LPP-IC-0231 and MCT-R-1954. In 2023, ''Farlowichnus rapidus'' was described by Giuseppe Leonardi, Marcelo A. Fernandes, Ismar S. Carvalho, Julia B. Schutzer, and Rafael C. da Silva as a new ichnogenus and ichnospecies of theropod footprints based on these fossil remains. The generic name, "''Farlowichnus''", combines a reference to James O. Farlow, a paleontologist who has studied ichnofossils, with the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

"ίχνος" ("ichnos"), meaning "track". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, "''rapidus''", references the hypothesized cursorial behavior and agile morphology of the taxon.

Description

Leonardi et al. (2023) described the general morphology of the ''Farlowichnus'' footprints as "waterdrop"-shaped. The impressions of the third digit of ''Farlowichnus'' are significantly longer than the second and fourth digits, which are proportionately much shorter. This morphology, as well as the observed long strides and high step angle, are associated with a

behavior. Although the footprints are structurally

tridactyl In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. The term is derived from the Greek word () meaning "finger." Sometimes the suffix "-dactylia" is used. The derive ...

, or the imprints of three toes are visible, ''Farlowichnus'' was likely functionally monodactylous. The foot shape also indicates adaptations for running in soft, dry sand. The dinosaur trackmaker of the ''Farlowichnus'' footprints may have reached lengths of up to , as indicated by the larger size of one of the paratype specimens. The holotype trackmaker was smaller, at about long, weighing around .

Classification

While the type of theropod that produced the ''Farlowichnus'' is unknown, Leonardi et al. (2023) speculate that it may have been a relative of noasaurids. It may have had a body morphology comparable to the similarly aged ''

Vespersaurus ''Vespersaurus'' (meaning "western lizard") is a genus of noasaurid theropod dinosaur from the Cretaceous Rio Paraná Formation in the Paraná Basin, Brazil. The type and only species is ''V. paranaensis'', which would have lived in the giant pre ...

'' from Brazil's

Rio Paraná Formation Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Fl ...

. The fossil material of ''Vespersaurus'' suggests that it was also monodactylous, a feature observed in the ''Farlowichnus'' trackways. However, Navarro et al. (2025) questioned the noasaurid interpretation for the trackmaker of ''Farlowichnus'' due to the difference in pedal and ungual anatomy compared to those of ''Vespersaurus''.

Paleoenvironment

''Farlowichnus'' was found in layers of the Botucatu Formation, which dates to the

Berriasian In the geological timescale, the Berriasian is an age/ stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 143.1 ±0.6 Ma and 137.05 ± 0.2 (million years ago) ...

–

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...

ages of the

. Fossil remains of several indeterminate animals, including

and large

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively sm ...

dinosaurs, mammals,

lacertilia Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

n reptiles, and invertebrates, have also been described from the formation. The mammalian ichnotaxon ''

Brasilichnium ''Brasilichnium'' is the name of fossilised mammaliamorph footprints dating from the Jurassic and Cretaceous. They have been identified from Brazil and western North America. ''Brasilichnium'' is the name of the footprints, identified by their sh ...

'' has also been identified from the formation.São Bento quarry, Araraquara
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org

References

{{Taxonbar, from=Q122884747 Theropod trace fossils Fossil trackways Fossil taxa described in 2023

Discovery and naming

Description

Classification

Paleoenvironment

See also

References