Tuesday, June 4, 2013

[PaleoOrnithology • 2009] Rapid Somatic Expansion Causes the Brain to Lag Behind: The Case of the Brain and Behavior of New Zealand's Haast's Eagle Harpagornis moorei

Haast's eagle Harpagornis moorei

New Zealand's late Pleistocene and Holocene Haast's eagle (Harpagornis moorei) was the sole predator of the moa (Aves: Dinornithiformes) and the largest eagle so far described. Recent molecular evidence has hypothesised that it evolved from a much smaller Asian/Australian eagle witthhin tht past 1.8 my. Osteometrof the igh-reaolution spirol computed tomography of skeletal remains of Haast's eagle were used to determine morphological and functionally significant characteristics of the central and peripheral nervous system and sensory apparatuses and to test these against hypotheses about behavior and evolution based on molecular and external morphology. Compared with other accipitrids, Haast's eagle had a proportionally low endocranial volume for its body weight. There was no anatomical evidence to support the significant use of olfaction by Haast's eagle, as the olfactory bulb size and cross-sectional area of the olfactory nerve foramen were no larger than would be expected for Accipitridae of this body weight. Both the size of the neural canal at the cervicothoracic junction and the brachial spinal quotient (ratio of neural canal area at cervicothoracic and caudal thoracic levels) were low, suggesting that the spinal cord at brachial levels was also small. These data are consistent with the hypothesis that Harpagornis had evolved to large size from a smaller ancestor and that the ancestors of Haast's eagle appear to have undergone rapid expansion of body size and elements of the hindlimb somatic nervous system at the expense of enlargement of the brain and visual, olfactory, and vestibular apparatuses.

2009. Rapid Somatic Expansion Causes the Brain to Lag Behind: The Case of the Brain and Behavior of New Zealand's Haast's Eagle (Harpagornis moorei). Journal of Vertebrate Paleontology. 29(3):637-649. 

Maori legend of man-eating bird is true 
Creature that features in New Zealand folklore really existed, scientists say


Haast's Eagle
Legends of the Maori people of New Zealand describe a man-eating monster bird called Te Hokioi. That legend is thought to have been inspired by Haast's eagle, a giant raptor that survived until only about 500 years ago. Haast's eagles were huge, weighing 40 lbs with a nine-foot wingspan and three-inch long talons. They used their formidable size and strength to subdue and kill prey much larger than themselves, including the moa, a massive flightless bird that weighed as much as 300 lbs. 

Birds That Eat People