Goniatitina

Goniatitina is a group of extinct cePhalopod mollusks that lived during the Paleozoic and Early Mesozoic eras. They were characterized by their internal shell, which was divided into several chambers. The Goniatitina lineage is believed to have originated from the ancestral group of Ammonoidea, to which modern squid and cuttlefish belong.

These marine animals were characterized by their spiral shells, which were typically divided into several whorls. The shell morphology of Goniatitina was highly variable, with some species exhibiting a compressed, flat shell, while others had a more elongated or even moderately coiled shell. In contrast to modern cephalopod shells, the Goniatitina shells often exhibited radial and sometimes longitudinal ornamentation, such as ridges, coarse ribs, and coarse, crowded tubercles.

Fossil evidence indicates that Goniatitina species were quite large, with some reports suggesting mature specimens reached up to 60 centimeters in length. It is worth noting, however, that estimates of shell size can vary widely depending on the quality of preservation. Goniatitina species were diverse and spread across numerous look-ups during the early Paleozoic. As the first modern cephalopod families began to appear, the Goniatitina gradually declined in prominence, dying out with their counterparts by the end of the Triassic.