''Batrachomimus'' 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 ...

neosuchian Neosuchia is a clade within Mesoeucrocodylia that includes all modern extant crocodilians and their closest fossil relatives. It is defined as the most inclusive clade containing all crocodylomorphs more closely related to ''Crocodylus niloticus' ...

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 ...

known from the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

Pastos Bons Formation The Pastos Bons Formation is a Late Jurassic ( Oxfordian to Kimmeridgian) geologic formation of the Parnaíba Basin in Maranhão, northeastern Brazil. The formation forms part of the sag phase of the basin. It overlies the Sardinha Formation an ...

of northeastern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. It contains a single

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, ''Batrachomimus pastosbonensis'', with 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 ...

referring to the formation, which was first described and named by Felipe C. Montefeltro, Hans C. E. Larsson, Marco A. G. de França and Max C. Langer in

2013 2013 was the first year since 1987 to contain four unique digits (a span of 26 years). 2013 was designated as: *International Year of Water Cooperation *International Year of Quinoa Events January * January 5 – 2013 Craig, Alask ...

. It is known from a nearly complete

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

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 ...

s and limb bones. ''Batrachomimus'' belongs to the family

Paralligatoridae Paralligatoridae is an extinct family of neosuchian crocodyliforms that existed during the Jurassic and Cretaceous periods. It includes the genera '' Paralligator'', '' Brillanceausuchus'', '' Kansajsuchus'', '' Shamosuchus'', '' Scolomastax'', ...

and predates all other members of the family and its immediate sister group,

Eusuchia Eusuchia is a clade of neosuchian Crocodylomorpha, crocodylomorphs that first appeared in the Early Cretaceous, which includes modern Crocodilia, crocodilians. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survi ...

, by 30 million years.

Description

''Batrachomimus'' is known from a single

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 ...

skull known as LPRP/USP-0617, which preserves most of the skull and lower jaws except for the

skull table The skull roof or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes, including land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium. In comparati ...

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, brain-pan, or brainbox, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calv ...

, and the left temporal region. The skull is about , giving an estimated total body length of about . ''Batrachomimus'' has a narrow snout with wavy margins around the teeth. It is unique in having a smooth area of bone on the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

, near the back of the snout; most crocodyliforms have heavy pitting covering the entire upper surface of the skull, including all of the maxilla. Another unique feature or autapomorphy of ''Batrachomimus'' is the hourglass-shape of its

choanae The choanae (: choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the pharynx, in humans and other mammals (as well as crocodilians and most skinks). They ...

, which are two holes on the underside of the skull that are openings for the nasal passages. Other distinguishing features of ''Batrachomimus'' are its lack of antorbital and

mandibular fenestrae The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

(holes in front of the eyes and at the back of the lower jaw, respectively), and a backward extension of the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

bone on the snout to the level of the fifth tooth of the maxilla bone behind it.

Etymology

The genus name "''Batrachomimus''" means "

batrachia The Batrachia are a clade of amphibians that includes frogs and salamanders, but not caecilians nor the extinct allocaudates. The name Batrachia was first used by French zoologist Pierre André Latreille in 1800 to refer to frogs, but has more ...

n mimic" in

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 ...

, a reference to the holotype specimen originally being identified as that of a

temnospondyl Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') or temnospondyls is a diverse ancient order (biology), order of small to giant tetrapods—often considered Labyrinth ...

, a type of prehistoric amphibian that vaguely resembles modern batrachians (frogs and toads). In addition to being considered a temnospondyl, the holotype was thought to have come from the

Pedra de Fogo Formation The Pedra de Fogo Formation is an Early Permian ( Kungurian) geological formation of the Parnaíba Basin, northeastern Brazil. It has outcrops mainly on the states of Maranhão and Piauí, as well as some in Tocantins. It is thought to have bee ...

, which dates back to the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

, a time when temnospondyls were the dominant form of large semi-aquatic animals. The genus name also alludes to crocodyliforms replacing temnospondyls as semi-aquatic predators during the Jurassic.

Phylogeny

The

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 of Montefeltro ''et al.'' (2013) placed ''Batrachomimus'' as the most basal member of the group Paralligatoridae, which also includes the genera ''

Shamosuchus ''Shamosuchus'' is an extinct genus of neosuchian 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 po ...

'' and ''

Rugosuchus ''Rugosuchus'' (meaning "uneven or wrinkled crocodile", in reference to texturing on its upper jaw bones) is an extinct genus of neosuchian crocodyliform from the Cretaceous of China. It is known from most of a skull, a partial postcranial ske ...

'' from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

of Asia. 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 ...

showing the results of the analysis:

References

{{Taxonbar, from=Q14635637, from2=Q20717138 Paralligatoridae Prehistoric pseudosuchian genera Monotypic vertebrate genera Oxfordian life Late Jurassic crocodylomorphs of South America Jurassic Brazil Fossils of Brazil Fossil taxa described in 2013