ck dv Thl Fig. 1. Leg feathers in the basal avialan Sapeorvis. Photograph (A) an
ID: 66952 • Letter: C
Question
ck dv Thl Fig. 1. Leg feathers in the basal avialan Sapeorvis. Photograph (A) and drawing (B). Abbreviations:cv cervical vertebrae; dv, dorsal vertebrae; If, leg feathers hl, left hindlimb; lil, left ilium; lis, left ischium; rhl, right hindlimb; sk, skllt tail feather Fig. 4. Evolution of leg feathers in cochurosaurian dinosaurs. Four major stages in the evolution of integumentary structures on the hindlimb are represented by the compsognathid Sinocalliopteryx (short filamentous feathers covering legs, including fect); the basal deinonychosaurian Anchiorvis and the basal avialan Sapeornis (large pennaccous feathers on legs, including feet, forming a winglike structure); the enantiornithine Cathayornis (large femoral and crural feathers forming a reduced winglike structure); and ornithuromorphs (small femoral and crural feathers and featherless feet).Explanation / Answer
Zheng et al., (2013) to a great extent support the arboreal glider hypothesis with some contrasting views. In fact, arboreal glider theory involves the study of functional morphology which determines that the ancestor of a flying group must have been a glider, and we think that it was a glider, and we think that it was an arboreal ( all modern non-aquatic gliders) then flight must have evolved from arboreal gliding ancestor. According to its phylogenetic analysis, Haramiyidia is placed within crown Mammalia denote the origin of crown Mammalia in the late Triassic period and followed with diversification in the Jurassic and thus contrast other estimated divergence times of crown mammals.
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