Actinolepidae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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

of placoderm fishes which lived during 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 P ...

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. They are considered to be among the most primitive of the

arthrodires Arthrodira (Greek for "jointed neck") is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ec ...

, and are widely accepted to be phylogenetically basal to the group.

Description

The bodies of Actinolepids are wide and flat, suggesting that most members of this family were

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

fish. Their jaws were comparatively underdeveloped in comparison to the more robust-jawed arthrodires that would come after them, such as ''

Dunkleosteus ''Dunkleosteus'' is an extinct genus of large armored, jawed fishes that existed during the Late Devonian period, about 382–358 million years ago. It consists of ten species, some of which are among the largest placoderms to have ever lived: ...

'' and ''

Coccosteus ''Coccosteus'' (from el, κόκκος , 'berry' and el, ὀστέον 'bone') is an extinct genus of arthrodire placoderm from the Devonian period. Its fossils have been found throughout Europe and North America. The majority of these have b ...

'', indicating that it likely subsisted primarily on smaller, softer-bodied animals such as mollusks or worms instead of larger, tougher prey animals.

References

External links

* Devonian placoderms Arthrodires Placoderm families Early Devonian first appearances Early Devonian extinctions {{Placoderm-stub