Arthrhabda
From Tlaquanaru
Contents |
Introduction
The Arthrhabda ("jointed rods"), along with the Fulgoraspida, are descendants of the most primitive eupanoplids. The order Arthrhabda is divided into four families, Arthratorpedidae, Pholidaspidae, Gomphaspidae, and Stephanaspidae.
Arthratorpedidae
The Arthratorpedos, or "Torpedofish," are a group of bullet-shaped fish that superficially resemble the poraspid and pteraspid heterostracans of Silurian and Devonian Earth. They are the most numerous and most diverse of the arthrhabdans, with both benthic and pelagic genera.
Pholidaspidae
The Pholidaspids are very distinctive, in that their armor is made up of numerous unfused pieces, rather than a series of bands (which formed from pieces that fused during either embryonic development, or during the larval stage). Most are squat, benthic forms, though, many have a seahorse, or pipefish-like bodyplan, and the trumpet-armors (genus Salpigkaspis) are long and slender "slurpgun" predators.
Gomphaspidae
Gomphaspis and Synichthys comprise the family Gomphaspidae. The thick plates of the thoracic armor are completely fused together to form a bullet-shape. They prey on invertebrates, with some species diving into soft substrate in pursuit. They are often confused with the arthrotorpedo genus Synoply.
Stephanaspidae
Stephanaspis is distinguished from the closely related Pholidaspids by the presence of complexly ornamented spines.
