Titaalik Rosae

Manus is defined as a term for the “distal” portion of the forelimb of an animal.   In Tiktaalik fossils, this refers to the forelimbs that were adapted for moving across substrate.   The axial skeleton in Tiktaalik fossils forms the frame of the body.   It consists of the notochord, vertebral column, and ribs.   The axial skeleton allows tetrapods to transfer their body weight to the girdles and appendages.   It also assists with rib movement which is essential for locomotion and breathing.   Tiktaalik fossils have also shown signs of imbrications of the ribs mean overlapping of the ribs.   The overlapping of the ribs gives the body more axial support as compared to species of fish that do not show imbrications because their body weight is supported by the deep waters.   Aside from the axial skeleton is the appendicular skeleton.   The appendicular skeleton includes the paired fins or limbs and the girdles.   More or less it is considered the braces within the body that support the skeleton.   The autopod on a tetrapod is considered the foot which in the case of the Tiktaalik fossils, means the fins that have been modified for walking on sediment. Homologous is defined as similarities in the evolution of two species.
The Tiktaalik fossils are approximately 380 million years old.   This time frame is considered “early Late Devonian.”   The Tiktaalik fossils were found in Nunavut Territory located in the Canadian Arctic.   Many were found near the river shallows of the Fram Formation.   “The Fram Formation is a Late Devonian sequence of rock strata located on Ellesmere Island.”   The Fram Formation consists of sediments derived from sediments that were laid down by a system of streams that meandered through.   Lowland habitats are warm and consist of slow-moving rivers.   These types of slow-moving waters encourage fish species that have a broad temperature tolerance and greater tolerance to low oxygen levels to inhabit these areas.   The areas had a subtropical to tropical climate...