''Boverisuchus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of planocraniid

crocodyliform Crocodyliformes is a clade of Crurotarsi, 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 ...

s known from the early to middle

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

(

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), 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 ...

stages) of

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

and western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It was a relatively small crocodyliform with an estimated total length of approximately .

History

The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

''Boverisuchus magnifrons'' was first named by paleontologist

Oskar Kuhn Oskar Kuhn (7 March 1908, Munich – 1 May 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 Mun ...

1938 Events January * January 1 – state-owned enterprise, State-owned railway networks are created by merger, in France (SNCF) and the Netherlands (Nederlandse Spoorwegen – NS). * January 20 – King Farouk of Egypt marries Saf ...

, from the

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

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

s of the type species of ''

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

'', ''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 ...

'' 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 Genus, generic name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti in 1768. ''Crocodylus'' contains 13–14 extant taxon, extant (living) 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, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

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 Na ...

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

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis. The name

Planocraniidae 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' ...

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 () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

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 group of crocodilians that, as originally formulated, included alligatoroids and crocodyloids, but not gavialoids. Results of molecular phylogenetic analysis uniformly draw gavialoids and crocodyloids into a close relationshi ...

, a group that includes

alligator An alligator, or colloquially gator, is a large reptile in the genus ''Alligator'' of the Family (biology), family Alligatoridae in the Order (biology), order Crocodilia. The two Extant taxon, extant species are the American alligator (''A. mis ...

caiman A caiman ( (also spelled cayman) from Taíno language, Taíno ''kaiman'') is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family (biology), family, the other being alligators. ...

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 more loosely to include ...

s but not

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

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, thymine, cytosine, and guanine. The ...

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 that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

, 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: lithost ...

data instead recovered the planocraniids outside crown group

Crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

. Below is a

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

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 ...

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

, 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 ...

(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 A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

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 (; 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 Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

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 K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event cau ...

. 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 amph ...

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