Brindabellaspis
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''Brindabellaspis stensioi'' ("
Erik Stensiö Prof Erik Helge Osvald Stensiö HFRSE (2 October 1891 – 11 January 1984), né Andersson, was an influential Swedish paleozoologist and founder of the so-called "Stockholm School" of vertebrate paleontology. He later took his new surnam ...
's
Brindabella Ranges The Brindabella Range, commonly called The Brindabellas or The Brindies, is a mountain range located in Australia, on a state and territory border of New South Wales and the Australian Capital Territory (ACT). The range rises to the west of C ...
Shield") is a
placoderm Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos'''Plate (animal anatomy), plate' and δέρμα 'derma'''skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Pal ...
with a flat, platypus-like snout from the
Early Devonian The Early Devonian is the first of three Epoch (geology), epochs comprising the Devonian period, corresponding to the Lower Devonian Series (stratigraphy), series. It lasted from and began with the Lochkovian Stage , which was followed by the Pr ...
of the Taemas-Wee Jasper reef in
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
. When it was first discovered in 1980, it was originally regarded as a Weejasperaspid acanthothoracid due to anatomical similarities with the other species found at the reef. According to Philippe Janvier, anatomical similarities of ''B. stensiois brain and braincase with those of jawless fish, such as the
Osteostraci The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed " ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, ...
and the
Galeaspida Galeaspida (from Latin, 'Helmet shields') is an extinct taxon of jawless marine and freshwater fish. The name is derived from ''galea'', the Latin word for ''helmet'', and refers to their massive bone shield on the head. Galeaspida lived in shallo ...
, strongly suggest that ''B. stensioi'', and also the antiarchs, are basal placoderms closest to the ancestral placoderm. New findings show ''B. stensioi'' may have evolutionary traits which connect its morphology to modern or crown-grouped jawed vertebrates, despite its resemblance to ancient jawless fish, showing an instability in the prevailing hypotheses of placoderm evolution.Endocast and Bony Labyrinth of a Devonian “Placoderm” Challenges Stem Gnathostome Phylogeny
/ref>


References


Further reading

* Young, Gavin C. 1980, A new Early Devonian placoderm from New South Wales, Australia, with a discussion of placoderm phylogeny: '' Palaeontographica'' 167A pp. 10–76. 2 pl., 27 fig. * Janvier, Philippe. Early Vertebrates Oxford, New York: Oxford University Press, 1998. * Long, John A. The Rise of Fishes: 500 Million Years of Evolution Baltimore: The Johns Hopkins University Press, 1996.


External links


Palaeos article on ''B. stensioi''
Placoderm genera Early Devonian fish Devonian placoderms Placoderms of Australia {{Placoderm-stub