Smit Original Early Drawing of Devonian Fishes

SMIT, Joseph (1836-1929).
Fishes of the Devonian Period (Glyptoloemus, Dipterus, Coccosteus, Osteolepis).
Original Illustration in pen, ink and grey wash, heightened in white.
c.1905-1912.
7 1/4" x 10 5/8" sheet.

Original artwork for Henry R. Knipe's Nebula to Man. Illustrated on page 26.

1. Glyptolepis is an extinct genus of porolepiform lobe-finned fish which lived during Devonian Period, from the early Eifelian to Frasnian Age.

2. Dipterus (meaning 'two wings') is an extinct genus of lungfish from the middle Devonian period of Europe and North America. In most respects, Dipterus, which was about 35 centimeters (14 in) long, closely resembled modern lungfish. Like its ancestor Dipnorhynchids, it had tooth-like plates on its palate instead of real teeth. However, unlike its modern relatives, in which the dorsal, caudal, and anal fin are fused into one, Dipterus's fins were still separated. It mostly ate invertebrates[citation needed], and had lungs, not an air bladder. These were more developed in Dipterus and are still seen in modern-day lungfish. The genus was established by Adam Sedgwick & Roderick Murchison in the year 1828.

3. Coccosteus ("seed bone") is an extinct genus of arthrodire placoderm. Its fossils have been found throughout Europe and North America. The majority of these have been found in freshwater sediments, though, such a large range suggests that they may have been able to enter saltwater. The largest specimens were about 40 centimeters (16 in), although the average length was 20 to 24 centimeters (7.9 to 9.4 in). Like all other arthrodires, Coccosteus had a joint between the armor of the body and skull. It also had an internal joint between its neck vertebrae and the back of the skull, allowing for the mouth to be opened even wider. Along with the longer jaws, this allowed Coccosteus to feed on fairly large prey. The up-and-down movement of the skull also allowed for more water to be pumped through the gills. Possibly, the creature supplemented its diet with organic material filtered from mud using the gills. As with all other arthrodires, Coccosteus had bony dental plates embedded in its jaws, forming a beak. The beak was kept sharp by having the edges of the dental plates grind away at each other. Overall the creature looked similar to its gigantic cousin Dunkleosteus, save that its eyes were closer to the end of its snout than in its larger relative.

4. Osteolepis ('bone scale') is an extinct genus of lobe-finned fish from the Devonian period. It lived in the Lake Orcadie of northern Scotland. Osteolepis was about 20 centimeters (7.9 in) long, and covered with large, square scales. The scales and plates on its head were covered in a thin layer of spongy, bony material called cosmine. This layer contained canals which were connected to sensory cells deeper in the skin. These canals ended in pores on the surface, and were probably for sensing vibrations in the water. Osteolepis was a rhipidistian, having a number of features in common with the tetrapods (land-dwelling vertebrates and their descendants), and was probably close to the base of the tetrapod family tree.