<div>There is no previously reported information on the morphological characteristics of pelvic limb long bones (femur, tibiotarsus and tarsometatarsus) in crested serpent eagle and brown wood owl. Thus, this study aimed to evaluate morphological and biometrical characteristics of pelvic limb long bones in crested serpent eagle and brown wood owl. The femur consisted of a curved shaft and two extremities. The shaft was wider proximally and distally and presented medial, lateral, anterior and lateral surfaces. The anterior, medial and lateral surfaces were smooth and continuous in both the species. An intermuscular line called linea aspera was present on the anterior and posterior surfaces in both the species. The proximal and distal extremities of the femur were almost of equal size. The proximal extremity presented a distinct, hemispherical head which was located in the level of the trochanter major in both the species. The distal extremity furnished a trochlea anteriorly for patella and medial, lateral condyles posteriorly for tibiotarsus bone. The patella was small and triangular and consisted of two surfaces, two borders, a base and an apex in both the species. Tibiotarsus was the longest bone in both the species which was formed by the fusion of distal extremity of the tibia with the proximal row of the tarsal bones. The proximal and distal extremity of the tibiotarsus consisted of medial and lateral condyles. In both the species, the fibula was a rod-shaped bone and reached up to distal third of the lateral border of the tibiotarsus. The tarsometatarsus was a long bone but smaller than tibiotarsus in both the species. Various biometrical parameters of the pelvic limb long bones were more in the crested serpent eagle as compared to the brown wood owl due to species differences.&nbsp;</div>


<div>Comparative Gross Anatomical Studies on Pelvic Limb Long Bones of Crested Serpent Eagle (<em>Spilornis cheela</em>) and Brown Wood Owl (<em>Strix leptogrammica</em>)</div>


<div style="text-align: justify;">Morphological and morphometrical study of pelvic limb bones from adult birds viz., ostrich (n=4), emu (n=6), domestic fowl (n=8) and duck (n=8) were carried out. Pubic symphysis was a distinctive feature of os coxae in ostrich. Medial surface of ilium was united to lumbosacral mass in ostrich and emu, whereas, only medial border made fusion in domestic fowl and duck. Post acetabular ilium was an elongated triangle in ostrich and emu, whereas, quadrilateral plate in domestic fowl and duck. Iliac fossae for kidneys were lacking in ostrich and emu. Ischium was a long rod in ostrich and emu. Ilio-ischiatic notch was present in ostrich and emu, while, ilio-ischiatic foramen was found in domestic fowl and duck. Caudal extremity of pubis was free in all the species studied excluding ostrich. Ostrich and emu exhibited a distinct pneumatic foramen on femur which was lacking in domestic fowl and duck. Length ratio of femur to tibiotarsus was 1:1.75, 1:1.88, 1:1.38 and 1:1.69 in ostrich, emu, domestic fowl and duck correspondingly. Lateral cnemial crest was a large tuberosity in ostrich; whereas, in other species it was a thick curved spine. &nbsp;Hypotarsus was in the form of spine in ostrich and emu. Bony spur of tarsometatarsus observed in male domestic fowl was lacking in the other species. Distal extremity showed two trochleae in ostrich, whereas, three trochleae, in the other species. Ostrich is the only didactyl bird with two digits. Emu possessed three digits, while, domestic fowl and duck possessed four. Our present study revealed pneumatic femur, longer tibiotarsus and tarsometatarsus and less number of digits in ostrich and emu. &nbsp;Reduction in number of phalanges also led to reduce the number of muscles and tendons associated to digits. The above mentioned features may aid ostrich and emu for high-speed locomotion.</div>

<div style="text-align: justify;">Comparative morphological studies of the pelvic limb bones in ostrich (<em>Struthio camelus</em>), emu (<em>Dromaius novaehollandiae</em>), domestic fowl (<em>Gallus gallus domesticus</em>) and duck (<em>Anas platyrhynchos domesticus</em>)&nbsp;</div>

Comparative Gross Anatomical Studies on Pelvic Limb Long Bones of Crested Serpent Eagle (Spilornis cheela) and Brown Wood Owl (Strix leptogrammica)

Comparative morphological studies of the pelvic limb bones in ostrich (Struthio camelus), emu (Dromaius novaehollandiae), domestic fowl (Gallus gallus domesticus) and duck (Anas platyrhynchos domesticus)