The Humerus of Eusthenopteron as a Puzzling Organization - Essay Example

The study of the Eusthenopteron humerus, in order to understand its histological and micro-anatomical organization, is the key element of the study and is intended to offer essential data that facilitates the knowledge of evolutionary steps that led to the establishment of the distinctive tetrapod limb bone architecture.

Therefore, the study involves imaging of numerous specimens obtained from primitive aquatic sarcopterygian Eusthenopteron in order to produce a broad palaeobiological dataset and make a comprehensive conclusion. The fossil species considered The dominant Eusthenopteron species in the Canadian, Miguasha, and Quebec regions were used in the study, and the abundant fossil material available made the investigation of ontogeny using size series possible. MethodologyThe study focused on the humeri obtained from two large and one small Eusthenopteron, all with three-dimensional preservation.

The small humeri used was ossified completely, thus interpreted as a juvenile, whereas one of the large humeri was preserved in articulation together with the ulna’s proximal end, as well as being in association with more fin endoskeleton distal elements and lepidotrichial proximal ends. The comparative aspects of these elements were done through scanning. These specimens were imaged by beamline ID19 of propagation phase-contrast X-ray synchrotron radiation microtomography (PPC-SRμCT) and European Synchrotron Radiation Facility (ESRF).

There was the use of a homogeneity assumption-based phase retrieval approach for the purpose of data reconstruction.FindingsAccording to the study observations, Eusthenopteron possesses a more unique combination of life history and biological traits compared to what had been thought before. In terms of its morphology, Eusthenopteron appears like a conventional predator fish that lacks definite terrestrial adaptations. It has numerous that resembles, both in proportion and size, the other sarcopterygians with lobed fins.

The humorous ossification started at least a half adult-size of the element and animal. On the other hand, the bones of the extant tetrapod limbs ossify earlier. The study reveals an organized spongiosa in the Eusthenopteron humerus, which appears to host functional bone marrow, and appears to have undergone extension growth just like the tetrapod. The slow growth in adults is a possible indication of sexual maturity onset. Approval of this assumption would mean the period of pre-reproductive growth took an entire decade, which is significantly longer than that of extant amphibians.