'' Megalichthyids were fairly primitive tetrapodomorphs, retaining a largely fish-like appearance. Like some other primitive
sarcopterygians, their bodies were covered in rhomboid
scales that possessed a layer of
cosmine (a porous, mineralised tissue). The scales however lacked the peg-and-socket articulations found in some other groups. The skulls of megalichthyids had a rather low and broad shape. Like the scales, the
dermal bones of the skull bore a layer of cosmine. The
nostrils were somewhat elongated, slit-like holes that were bordered in the front by the
lateral rostral bone and in the back by the
posterior tectal bone. The
premaxilla (one of the bones of the upper jaw) had a well-developed posterior process, and bore a large
tusk that either interrupted the main tooth row or was located further inside the mouth, depending on the species. The
maxilla (another bone of the upper jaw, located behind the premaxilla) was rather tall, especially towards the rear end. The
vomers (a pair of bones in the
palate) were short and broad, with a well-developed mesial process in some cases. The
lacrimal bone had a prominent notch. The front end of the
parietal bone had a concave shape where it contacted the
posterior nasal bone. The
pineal foramen (a hole located at the top of the skull in some vertebrates, containing the parietal eye) was absent. The
supratemporal bone had a forwards-pointing process that lacked a covering of cosmine. The
squamosal bone was nearly equal in height and width. The
preopercular was a fairly short, vertically aligned bone. The
opercular series (a set of bones protecting the
gills) consisted of three bones, the opercular and two suboperculars. The opercular was large and almost square-shaped. The suboperculars were in contact with the last or second-last of the
submandibular bones (a group of bones lying beneath the
dentary bone of the lower jaw). The
pectoral fins were large and had a fan-like shape. == Classification ==