Homostiids have flattened and elongated skulls, "toothless" jaws and large sizes, suggesting that many were probably filter feeders, similar to the noticeably flattened whale shark.[2][3][4][5] According to Denison 1978, primitive homostiids have moderately long median dorsal plates, whereas in "advanced" homostiids, the median dorsal tends to be short and broad.[1]: 69
A comparatively large animal from the Middle Devonian of Siberia, with a head shield estimated around 40 centimeters long. Known only from an infragnathal bone, and an intero-lateral and a marginal plate.
A primitive homostiid from Emsian-aged strata of Morocco. Antineosteus' primitive anatomical features suggest it may be a precursor to Angarichthys, Atlantidosteus and Homosteus. Antineosteus lived sympatrically with the Moroccan species of Atlantidosteus.
This genus is known from species found in Emsian-aged Morocco and Middle Devonian Australia. Overall form is very similar to Antineosteus and Homosteus.
This genus is known from isolated plates and fragments from Lower Devonian-aged strata in Spitzbergen and Germany. The holotype of the type species, E. depressa, is a paranuchal plate very similar to those seen in coccosteids.
A very large, primitive form from the Early Devonian Taemas-Wee Jasper Reef fauna. Its discoverer, Gavin Young, hypothesizes that it may have been a filter-feeder.
Tityosteus is thought to be the largest vertebrate known from the Lower Devonian, with an estimated length of 2.5 meters. The holotype is an incomplete individual from the Hunsrück.[1]: 73
References
^ abcDenison R (1978). Handbook of Paleoichthyology. Vol. 2: Placodermi. Stuttgart New York: Gustav Fischer Verlag. ISBN978-0-89574-027-4.
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