User:Rschrier

Characteristics
""Dunkleosteus"" some have suggested that placoderms such as Dunkleosteus were outcompeted by the smaller, swifter fishes, such as the early shark Cladoselache. However, others have pointed out that this assessment fails to take into account that predatory placoderms would have inhabited different ecological niches than the early sharks during the Devonian period.

Similarities
Dunkleosteus, like most other placoderms, may have also been among the first vertebrates to internalize egg fertilization, akin to the modern process of vivipary as seen in some modern sharks. The first recorded | sexual dimorphismappeared in the middle-Devonian ptyctodontid placoderm Rhamphodopsis, which had external clasping organs on males that are strong indicators of intromittent sexual intercourse and internal fertilization. Claspers are modified structures at the base of the pelvic fins which transmit sperm directly inside the female. Females had wide pelvic basal plates.