Fumihito Akishinonomiya

Coxa morphologically adapted to large egg in aepyornithid species compared with various palaeognaths.

With 12 figures and 3 tables

Morphological variation in brain through domestication of fowl

Great variations in the size, shape, color, feather structure and behavior are observed among fowl breeds. Because many types of domestic fowls have been bred for various purposes, they are ideal to assess the relationship between brain morphology and avian biology. However, little is known about changes in brain shape that may have occurred during fowl domestication. We analyzed the brains of red jungle fowl and domestic fowl to clarify differences in the brain shape between these breeds, as well as the shape changes associated with size enlargement using three‐dimensional geometric morphometrics. Principal component and multivariate regression analyses showed that ventrodorsal bending, anteroposterior elongation and width reduction were significantly correlated with brain size. According to the size‐dependent analysis, the red jungle fowl brain has an intermediate shape between the brain of young broilers and that of large domestic fowl and adult broilers. After the size effect is removed, geometric morphometric analyses show that the brain of red jungle fowl is different from that of domestic fowl, with large round cerebral hemispheres. Significant correlations exist between the skull length and brain volume among fowl, while the brain volume relative to the skull length is distinctly larger in red jungle fowl compared with domestic fowl. The distinct brain shape and increased relative brain size of red jungle fowl may be driven by the presence of large, rounded cerebral hemispheres.

Musculoskeletal System of Huge Tarsometatarsal Region in the Dong Tao Fowls from North Vietnam

A macroscopic examination of the huge leg of the Dong Tao breed from North Vietnam was conducted. Bone and muscular tendon morphometric data demonstrated that the Dong Tao breed was equipped with the extraordinarily thick and large tarsometatarsal bone and distal parts of the related tibiotarsus regions. Morphological differences between dorsal and plantar sides were clearly observed. First, on the dorsal side, fleshy bundles were extended effectively using the enlarged dorsal surface of tarsometatarsal bone shown as Musuculus extensor digitorum brevis, M. extensor digiti I brevis and M. adductor digiti IV. The strong and fleshy extensor bellies of M. tibialis cranialis and M. extensor digitorum longus were enlarged in the crural region, functioning to dorsally pull the heavy tarsometatarsal region through the ankle joint. Second, on the plantar side, the flexor tendon groups around the ankle joint were wider and thicker than those of other ordinary breeds, possibly to stabilize the tarsometatarsal bone and to flex the phalange as observed in M. flexor perforatus digiti II, M. flexor perforans et perforatus digiti II, M. flexor perforatus digiti III, M. flexor perforans et perforatus digiti III, M. flexor perforatus digiti IV, and M. flexor perforans digitorum profundus. The mass of the huge tarsometatarsal region does not contribute to effective locomotion in the Dong Tao fowl in comparison with that associated with normal breeds. However, we suggest that these morphological changes in the musculoskeletal system may functionally compensate for the physical disadvantages of the large weight of the distal part of the hindlimb in the Dong Tao fowl.

Geographical variation in the skeletal morphology of red jungle fowl

ABSTRACT 1. The skulls and postcranial skeletons of the red jungle fowl (Gallus gallus) were compared osteometrically between the populations from North and South Vietnam, North and Central Laos and Southeast Bangladesh. The populations include the three subspecies of G. g. spadiceus, G. g. gallus and G. g. murghi and were sampled to reveal the geographical morphological variations among populations in G. gallus. 2. The morphometric characteristics of subspecies murghi could be clearly distinguished from those of the other subspecies using a canonical discriminant analysis. However, the size and shape of the skull of the gallus population from South Vietnam were not statistically different from that of the subspecies spadiceus from North Laos. The canonical discriminant scores also clearly indicated that there were morphological similarities in the skulls of the populations from North Laos and South Vietnam. 3. From the results, therefore, it is concluded that red jungle fowls do not exhibit high levels of osteometric variation between geographical localities at least within the Indochinese Peninsula. 4. This contrasts with previous studies which have described these subspecies as having various external morphological differences and have argued that zoogeographical barriers exist between the north and south areas of the Indochinese Peninsula.