Brush-tailed rock wallaby (Petrogale penicillata)
Family Macropodidae
These wallabies inhabit rock-piles and cliffs along the eastern coast of Australia from 100 km north of Brisbane to the Victorian border. They can move with agility around rocks, using their large tail as a counterbalance as they climb and hop from rock to rock.
The brain of the brush-tailed rock wallaby is about 24 ml in volume. The forebrain has the characteristic triangular shape seen in all macropod diprotodontids, with prominent sulci on the surface of the cerebral isocortex. All the macropod brains exhibit a pronounced dorsoventral flexion due to the elevation of the rostral parts of the skull. Olfactory bulbs protrude anteriorly, but are not as relatively prominent as in dasyurids. Functional areas have not been mapped in this species but putative functional areas in the isocortex have been indicated based on cytoarchitectural and electrophysiological studies in other related macropods (tammar wallaby Macropus eugenii; Ashwell et al., 2005; Hemmi and Mark, 1998; Waite et al., 1991). Macropods have a barrel-field in the head area of the primary somatosensory cortex. Each barrel is composed of a clump of small neurons in layer 4 of the cerebral cortex. The barrels correspond to vibrissae (hairs) on the snout (mystacial area) and other parts of the head and represent discrete areas where the somatosensory (tactile) information from each vibrissa is processed in the cortex. The cerebellum is foliated and the cerebellar hemispheres are elaborate, indicating expansion of the cerebro(ponto)cerebellar circuitry for complex learned motor behaviour.
Ashwell KWS, Zhang L-L, Marotte LR (2005) Cyto- and chemoarchitecture of the cortex of the tammar wallaby (Macropus eugenii): areal organization. Brain Behavior and Evolution, 66, 114-136.
Hemmi JM, Mark RF (1998) Visual acuity, contrast sensitivity and retinal magnification in a marsupial, the tammar wallaby (Macropus eugenii). Journal of Comparative Physiology A, 183, 379-387.
Waite PM, Marotte LR, Mark RF (1991) Development of whisker representation in the cortex of the tammar wallaby Macropus eugenii. Developmental Brain Research, 58, 35-41.
This figure above is an illustration of the organisation of the external anatomy mapped on the Brushtail rock wallaby brain, with abbreviations for each section explained below the illustration.
This figure above is an illustration of the superior lateral view of the organisation of the external anatomy mapped on the Brushtail rock wallaby brain, with abbreviations for each section explained below the illustration.
This figure above is an illustration of the ventral organisation of the external anatomy mapped on the Brushtail rock wallaby brain, with abbreviations for each section explained below the illustration.
