''Mcnamaraspis'' 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 ...

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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 ...

arthrodire Arthrodira (Greek for "jointed neck") is an Order (biology), order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetratin ...

placoderm that inhabited the ancient reef system of north

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

during the

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during th ...

epoch of the

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wher ...

period (c. 380-375 million years ago). The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

was found and described by

John A. Long John Albert Long (born 1957) is an Australian paleontologist who is currently Strategic Professor in Palaeontology at Flinders University in Adelaide, South Australia. He was previously the Vice President of Research and Collections at the Natur ...

from the

Gogo Formation The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community. The formation is named after Gogo Station, a cattle station where outcrops appear and fossils ...

near

Fitzroy Crossing Fitzroy or FitzRoy may refer to: People As a given name *Several members of the Somerset family (Dukes of Beaufort) have this as a middle-name: **FitzRoy Somerset, 1st Baron Raglan (1788–1855) ** Henry Charles FitzRoy Somerset, 8th Duke of Beau ...

. This fossil fish showed new anatomical features in arthrodires, like the well-preserved annular (ring-shaped)

cartilages Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and ...

of the snout, previously inferred to be present by

Erik Stensiö Prof Erik Helge Osvald Stensiö HFRSE (2 October 1891 – 11 January 1984) was a Sweden, Swedish paleozoology, paleozoologist. He later took his new surname from his place of origin and is occasionally referred to with both names (as Erik Ander ...

of Sweden. It is occasionally referred to as "The Gogo Fish" after the locale the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

was excavated from. On 5 December 1995, 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 ...

, ''M. kaprios'', was officially proclaimed as the

State Fossil Most American states have made a state fossil designation, in many cases during the 1980s. It is common to designate one species in which fossilization has occurred, rather than a single specimen, or a category of fossils not limited to a single ...

emblem of

by the

Governor of Western Australia The governor of Western Australia is the representative in Western Australia of the monarch of Australia, currently King Charles III. As with the other governors of the Australian states, the governor of Western Australia performs constitutional ...

, thus becoming the first official state fossil emblem for any state of Australia.

Description

''M. kaprios'' is an extinct marine fish that grew up to in length. With its large eyes, articulated jaw and sharp, razorlike dentition plates, it can be inferred that this midsize placoderm was an active predator that specialized in cracking through the shelled defenses of arthropods such as

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

s. It has a distinct cartilaginous snout not recorded in other placoderms.

Phylogeny

''Mcnamaraspis'' was originally classified as a member of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Plourdosteidae. However,

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 later found Plourdosteidae to be an invalid grouping, and the family was dismissed. ''Mcnamaraspis'' is now considered to be a member of the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Incisoscutoidea Incisoscutoidea is an extinct superfamily of arthrodire placoderms that lived during the Devonian period. Phylogeny Eubrachythoraci is divided into the sister clades Pachyosteomorphi and Coccosteomorphi, the latter of which can be further ...

, which belongs to the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Coccosteomorphi Coccosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci (of the suborder Brachythoraci), armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, lea ...

, one of the two major clades within

Eubrachythoraci Eubrachythoraci is an extinct clade of arthrodire placoderms within the suborder Brachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, leading to their widespread d ...

. The

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 ...

below shows the

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

of ''Mcnamaraspis'':

References

Arthrodires Gogo fauna Placoderms of Australia Fossil taxa described in 1995 {{placoderm-stub