''Palanasaspis chekhivensis'' is an extinct species of

pteraspidid Pteraspididae is an extinct family of heterostracan vertebrates. It is an Early Devonian-aged family that contains the stereotypical, torpedo-shaped pteraspidids, such as the type genus, ''Pteraspis'', and its close relatives '' Errivaspis'' and ...

heterostracan Heterostraci (Ancient Greek, ἕτερος+ὄστρακον "those itha different shell" i is pl. of -us is an extinct subclass of pteraspidomorph jawless vertebrate that lived primarily in marine and estuary environments. Heterostraci exi ...

agnatha Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct ( conodonts and ostracoderms) species. Among recent animals, cyclosto ...

n which existed during the

Pragian The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.8 ± 2.8 million years ago to 407.6 ± 2.8 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important La ...

epoch of the early

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, whe ...

period in what is now

Podolia Podolia or Podilia ( uk, Поділля, Podillia, ; russian: Подолье, Podolye; ro, Podolia; pl, Podole; german: Podolien; be, Падолле, Padollie; lt, Podolė), is a historic region in Eastern Europe, located in the west-central ...

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

. It is known primarily from a wide

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

plate Plate may refer to: Cooking * Plate (dishware), a broad, mainly flat vessel commonly used to serve food * Plates, tableware, dishes or dishware used for setting a table, serving food and dining * Plate, the content of such a plate (for example: ...

, which is referenced in the generic name, a compound word combining the Latin words ''pala'', "shovel," and ''nasus'', "nose," with the Greek suffix ''aspis,'' "a small shield." Although the rostral plate clearly marks the creature as a pteraspidoid heterostracan, that literally nothing else of its anatomy is known forces researchers to leave it as ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

''.

References

Pteraspidiformes genera Devonian jawless fish Early Devonian fish Early Devonian fish of Europe Heterostraci enigmatic taxa Early Devonian first appearances Early Devonian genus extinctions Pragian life {{Devonian-jawless-fish-stub