Anaspida

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Anaspida
Temporal range: 444–358.9 
Ma
Late Devonian
Cowielepis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Superclass: Anaspidomorphi
Class: Anaspida
Traquair
, 1899
Type species
Birkenia elegans

Traquair 1898
Orders
Synonyms
  • Anaspidi
  • Birkeniae

Anaspida ("shieldless ones") is an extinct group of

phylogenetic analysis,[4] although some analysis show these group would be at least related.[5] Anaspids were small marine fish that lacked a heavy bony shield and paired fins, but were distinctively hypocercal
.

Anatomy

Compared to many other

synapomorphy for the anaspids is the large, tri-radiate spine behind the series of the gill openings.[1]

Taxonomy

Now that

Birkeniida, which contains all other recognized anaspid taxa.[9] Birkeniida is further divided into several families, including Birkeniidae, Pterygolepididae, Rhyncholepididae and Pharyngolepididae, which contain those taxa known from whole body fossils (in addition to several taxa known only from scales) and the family Septentrioniidae, whose subtaxa are known exclusively from scales.[9] Two recently described genera, Kerreralepis[8] and Cowielepis,[10] are considered to be Birkeniida incertae sedis
.

Some recent studies have suggested that anaspids are stem-

A newer taxonomy based on the work of Mikko's Phylogeny Archive,[11] Nelson, Grande and Wilson 2016[12] and van der Laan 2018.[13]

  • ClassAnaspida Janvier 1996 non Williston 1917
    • Order
      Endeiolepidiformes
      Berg 1940
      • Family
        Endeiolepididae
        Stensiö 1939 corrig.
    • OrderBirkeniiformes Berg 1940
Life reconstruction of Lasanius problematicus

Notes

  1. ^ a b Janvier, Philippe (1997) Anaspida The Tree of Life Web Project.
  2. .
  3. .
  4. .
  5. ^ .
  6. .
  7. ^ Sansom, Robert S., et al. "Taphonomy and affinity of an enigmatic Silurian vertebrate, Jamoytius kerwoodi White." Palaeontology 53.6 (2010): 1393-1409.
  8. ^ a b Blom, Henning. "New birkeniid anaspid from the Lower Devonian of Scotland and its phylogenetic implications." Palaeontology 55.3 (2012): 641-652.
  9. ^ a b Blom, Henning, T. Märss, and C. G. Miller. "Silurian and earliest Devonian birkeniid anaspids from the Northern Hemisphere." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 92.03 (2001): 263-323.
  10. ^ Blom, Henning. "A new anaspid fish from the Middle Silurian Cowie Harbour fish bed of Stonehaven, Scotland." Journal of Vertebrate Paleontology 28.3 (2008): 594-600.
  11. ^ Haaramo, Mikko (2003). "†Anaspida – anaspids". In Mikko's Phylogeny Archive. Retrieved November 25, 2018.
  12. .
  13. ^ van der Laan, Richard (2018). "Family-group names of fossil fishes". {{cite journal}}: Cite journal requires |journal= (help)

External links