From Sedes Draconis
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Dolicocephalines are one of the two subfamilies of Family Hominidae. Their name means "long-heads" because their skulls are longer and narrower than those of the other subfamily, the eurycephalines. The two subfamilies of Hominidae represent two different strategies for dealing with the expanded, extended development of the brain.
Dolicocephalines accommodate the extended brain growth by being born at an very early stage of development compared to eurycephalines. Dolicocephaline infants are born after a comparatively short gestation period (about 200 days). At birth, infants weigh just 1 or 2 kilograms (about 3-5% of adult weight), with comparatively underdeveloped lungs, reflexes, and immune systems. Most significantly dolicocephaline infants are born with very soft, loose skulls that can accommodate a great deal of continued brain growth after birth. The cranial sutures (the gaps between the plates of the skull) remain apparent for 3.5 to 4 years. All this means that dolicocephaline infants require much more intensive care for their first several months of life, and continuing through several years.
The feature that gives the name of the dolicocephalines (their longer skull) is a secondary adaptation. Since dolicocephalines did not widen the birth canal and pelvic girdle as eurycephalines did, as dolicocephalines continued to evolve larger brains their skulls expanded in a mostly linear direction instead of the more globular skull expansion of the eurycephalines.
Featured Picture: EvolutionaryClade.png
A chart showing the relationships of animal taxa on Sedes Draconis. With emphasis on vertebrates and taxa containing sentient species. All taxa shown are currently alive; no extinct taxa shown.
Across the top are the sentient species.