The picture shows the portrait of the calico fish dedicated to me by Gunnar Gad.

Please also note the graphics by Gunnar Gad in:

Kattmann U. & Gad, G. (2007). The slope rodents of the Columbana Archipelago. Factors and forms of speciation. Teaching Biology, 31 (325).
Dulitz, B. & Kattmann, U. . (2017). Exploring evolution through play: Speciation in the hill rodents. Unterricht Biologie, 41 (422), 15-41 (Dice game to experience the speciation and adaptive radiation of hill rodents).

Functions of fish pines

Do you know what functional morphology is, no? Well, this picture may help to clarify it. You can look at the blueprints of animals as a map: The lungs are close to the heart, the intestines underneath. The blueprints of animals have long been described in this way, only much more precisely. Entire books were filled with them and at some point it was believed that everything had been recorded and mapped.
But we are slowly gaining a different understanding of organisms, if we have a plan, then one that explains how all the parts work together. After all, animals are living beings and every detail usually has a function. We are now looking at functional relationships, with the success of viewing organisms as a unit and not as a sum of parts.
We should now be able to look at structures and draw conclusions about their function. Modern bony fish are a good example. They have exploited all the food sources available in the sea. They have only one tool for this, their jaws. This jaw has been modified for all possible forms of nutrition.
In order for a fish jaw to exert the kind of force that the calf fish uses to crush even large snails, the bones must be at the right angle to each other and the ligaments and muscles must be in the right place, otherwise it won't work. In the case of the catfish, it definitely works just right - because it is and remains the terror of all shellfish.