Weigeltaspis
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''Weigeltaspis'' is a
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 ...
of extinct
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
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
known from the Late
Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...
and Early Devonian periods. Fossils are known primarily from Early Devonian-aged marine strata of
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
and
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. Fragments and disarticulated plates of what may be of ''Weigeltaspis'' are known from Late Silurian-aged marine strata of Arctic
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. Rare articulated fossils, plus the overall anatomy of its plates suggest the living animals were, at least superficially, similar to psammosteids, some authorities, such as Tarlo, place them within Psammosteida.Tarlo, Halstead. "LB t1965) Psammosteiformes tAgnatha)—A review with descriptions of new material from the Lower Devonian of Poland, II. Systematic Part." Palaeontologia Polonica 15: 168. Pages 20-21 Because the ornamentation on the plates and scales are very similar to the ornamentation seen on the plates and scales of '' Traquairaspis'' to the point of constant confusion, other authorities follow the lead of Obruchev, and place ''Weigeltaspis'' within Traquairaspidiformes. Still other authorities remain unconvinced of either side, and, instead, follow Denison's lead to simply treat ''Weigeltaspis'' 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

Devonian jawless fish Silurian jawless fish Heterostraci genera Heterostraci enigmatic taxa Early Devonian fish of Europe Devonian fish of North America Fossils of Canada Silurian first appearances Devonian extinctions {{Pteraspidomorphi-stub