''Boverisuchus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

planocraniid Planocraniidae is an extinct family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, ''Boverisuchus'', ''Duerosuchus'' and ''Planocrania''. Pla ...

crocodyliform Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudo ...

s known from the middle

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

(

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Midd ...

stage) of

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

and western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It grew to approximately in length.

History

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''Boverisuchus magnifrons'' was first named by paleontologist

Oskar Kuhn Oskar Kuhn (7 March 1908, Munich – 1990) was a German palaeontologist. Life and career Kuhn was educated in Dinkelsbühl and Bamberg and then studied natural science, specialising in geology and paleontology, at the University of Munich, fr ...

1938 Events January * January 1 ** The Constitution of Estonia#Third Constitution (de facto 1938–1940, de jure 1938–1992), new constitution of Estonia enters into force, which many consider to be the ending of the Era of Silence and the a ...

, from the

of Germany alongside ''Weigeltisuchus geiseltalensis''. Most paleontologists have considered both species to represent

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

s of the type species of ''

Pristichampsus ''Pristichampsus'' ("saw crocodile") is a non-diagnostic extinct genus of crocodylian from France and possibly also Kazakhstan that is part of the monotypic Pristichampsidae family. As the type species, ''Pristichampsus rollinatii'', was based o ...

'', ''P. rollinatii''. Following a revision of the genus ''Pristichampsus'' by Brochu (2013), ''P. rollinati'' was found to be based on insufficiently diagnostic material and therefore is a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'' while ''Boverisuchus'' was reinstated as a valid genus. Brochu (2013) also assigned ''

Crocodylus ''Crocodylus'' is a genus of true crocodiles in the family Crocodylidae. Taxonomy The generic name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti in 1768. ''Crocodylus'' contains 13–14 extant (living) species and 5 extinct species ...

vorax'', which has been referred to as ''Pristichampsus vorax'' since Langston (1975), as the second species of ''Boverisuchus''. According to Brochu (2013), material from the middle Eocene of

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

may represent another yet unnamed species. The two Asian species of ''

Planocrania ''Planocrania'' is an extinct genus of eusuchian crocodyliforms from what is now China. Two species are currently known to belong to the genus. History The type species, ''Planocrania datangensis'', was named in 1976 from material found from Nan ...

'' were found to be most closely related to ''Boverisuchus'' using a

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis. The name

Planocraniidae Planocraniidae is an extinct family (biology), family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, ''Boverisuchus'', ''Duerosuchus'' and '' ...

was reinstated to contain these genera and replace Pristichampsidae.

Phylogeny

Phylogenetic analyses based purely on morphological data have generally placed Planocraniidae in a basal position within the

crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

. Some of these analyses have found that planocraniids lie just outside

Brevirostres Brevirostres is a paraphyletic group of crocodilians that included alligatoroids and crocodyloids. Brevirostres are crocodilians with small snouts, and are distinguished from the long-snouted gharials. It is defined phylogenetically as the last ...

, a group that includes

alligator An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...

caiman A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...

s, and

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

s but not

gharial The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...

s. However, molecular studies using

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

have found the group Brevirostres to be invalid upon finding that crocodiles and gavialids are more closely related than alligators. A 2018

tip dating Tip dating is a technique used in molecular dating that allows the inference of time-calibrated phylogenetic trees. Its defining feature is that it uses the ages of the samples to provide time information for the analysis, in contrast with traditio ...

study by Lee & Yates using both

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

, morphological and

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

data instead recovered the planocraniids outside crown group

Crocodylia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...

. Below is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

from that study: In 2021, Rio & Mannion conducted a new

study using a heavily modified morphological data set, and also noted the lack of consensus and difficulty in placing Planocraniidae. In their study, they recovered Planocraniidae within Crocodylia, as the

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

Longirostres Longirostres is a clade of crocodilians that includes the crocodiles and the gavialids, to the exclusion of the alligatoroids. Named in 2003 by Harshman ''et al.'', Longirostres is a crown group defined phylogenetically as including the last com ...

, as shown in the cladogram below:

Description and habits

Based on other planocraniids, ''Boverisuchus'' is assumed to have had heavily armoured skin, and long limbs suggesting 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 u ...

(i.e. running) habitus. It also had hoof-like toes, suggesting that it lived more on land than in the water, and that it therefore probably hunted terrestrial

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s. The

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

of ''Boverisuchus'' were ziphodont; i.e., laterally compressed, sharp, and with serrated edges (characteristic of terrestrial crocodyliforms that are unable to dispatch their prey by drowning them). Due to their similarity to those of certain

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s they were initially mistaken for theropod teeth, leading paleontologists to believe that some non-avian dinosaurs survived the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

. Some material referred to ''Pristichampsus rollinatii'' shows further features adapting the animal to this lifestyle. The tail was more reminiscent of a dinosaur's, being round in cross-section and lacking the

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amp ...

crest observed in extant crocodile species. It would also have been capable of

galloping The canter and gallop are variations on the fastest gait that can be performed by a horse or other equine. The canter is a controlled three-beat gait, while the gallop is a faster, four-beat variation of the same gait. It is a natural gait po ...

.Rossmann T. 2000. Studies on Cenozoic crocodiles: 5. Biomechanical investigation on the postcranial skeleton of the Palaeogene crocodile ''Pristichampsus rollinatii'' (Eusuchia: Pristichampsidae). ''Neues Jahrbuch fuer Geologie und Paläontologie Abh.'' 217 (3) 289-300.

References

{{Taxonbar, from=Q15076407 Neosuchians Eocene crocodylomorphs Eocene reptiles of Europe Eocene reptiles of North America Terrestrial crocodylomorphs Fossil taxa described in 1938 Prehistoric pseudosuchian genera

History

Phylogeny

Description and habits

See also

References