Phyllolepididae is one of two

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

of phyllolepid

placoderms Placodermi (from Greek πλάξ 'plate' and δέρμα 'skin', literally 'Plate (animal anatomy), plate-skinned') is a Class (biology), class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devoni ...

. The family, as a whole, is believed to be descended from the Chinese placoderm, '' Gavinaspis ''(which forms the other,

monotypic 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 ...

family, "Gavinaspididae"). All but two genera are, more or less, restricted to freshwater habitats of the Early to Middle Devonian of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. By 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 ...

, the genus '' Placolepis'' would spread throughout the world, with fossils being found in Australia,

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

, and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

, and by the start of the

Famennian The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used b ...

, phyllolepids would become extinct in Australia (then eastern

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

), with only species of '' Phyllolepis'' surviving in freshwater environments of Europe and North America. With the exception of '' Yurammia''. all phyllolepids have distinct ornamentation consisting primarily of concentric rings.

Genera

''Phyllolepis''

The type genus is restricted to freshwater Famennian strata of Europe and North America. It is also the youngest genus of phyllolepid, being the only taxon that survived the Frasnian-Famennian extinction event. Most species are known only from isolated or fragmented plates. Gill arches seen in whole fossils of the recently described ''P. thomsoni'', together with the castanets-shaped mouths typical of the family, confirm that phyllolepids were suctorial predators analogous to

goosefish Goosefishes are anglerfishes in the family Lophiidae found in the Arctic, Atlantic, Indian, and Pacific Oceans, where they live on sandy and muddy bottoms of the continental shelf and continental slope, to depths of more than . Like most other an ...

or flatheads.

''Placolepis''

This Frasnian genus is the most widespread phyllolepid, with fossils found in Australia, Turkey, Venezuela and Antarctica. Phyllolepids Placoderms of Europe Placoderms of Australia Placoderms of North America Placoderms of Antarctica Placoderm families {{placoderm-stub