Common ostrich
Common ostriches usually weigh from , or as much as two adult humans. The Masai ostriches of East Africa ("S. c. massaicus") averaged in males and in females, while the nominate subspecies, the North African ostrich ("S. c. camelus"), was found to average in unsexed adults. Exceptional male ostriches (in the nominate subspecies) can weigh up to . At sexual maturity (two to four years), male common ostriches can be from in height, while female common ostriches range from tall. New chicks are fawn in colour, with dark brown spots. During the first year of life, chicks grow at about per month. At one year of age, common ostriches weigh approximately . Their lifespan is up to 40–45 years.
Microtriches
Though microtriches have been described for several decades, the consensus terminology for the structure was made only at the turn of the 21st century. Standardised terms were resolved based on discussions that occurred at the International Workshops on Cestode Systematics in Storrs, Connecticut, United States in 2002, in Ceské Budejovice, Czech Republic in 2005 and in Smolenice, Slovakia in 2008. The following terms were endorsed for the components of each microtrix: the distal, electron-dense portion is the "cap", the proximal more electron-lucent region is the "base", and these two parts are separated from one another by the "baseplate". The base is composed of, among other elements, microfilaments, while the cap is composed of cap tubules. The electron-lucent central portion of the base is referred to as the "core". The core may be surrounded by an electron-dense tunic. The entire microthrix is enveloped by a plasma membrane, the external layer of which is referred to as the glycocalyx. Two distinct sizes of microtriches are recognised: those < or = 200 nm in basal width, termed "filitriches", and those >200 nm in basal width, termed "spinitriches". Filitriches are considered to occur in three lengths: papilliform (< or = 2 times as long as wide), acicular (2-6 times as long as wide), and capilliform (>6 times as long as wide). Spinitriches are much more variable in form.