Owing to the vital, water-conserving roles of the AQP2, -5, and -6 gene clusters in extant amphibians, sauropsids, and mammals, it is suggested that lineage-specific evolution of these apomorphic
gene clusters was permissive for vertebrate terrestrial adaptation.
In particular, we presume that spiny proventriculi--derived from an omnivorous ancestor and modified for herbivory--are ubiquitous or at least plesiomorphic in Phasmatodea, and "gastric caeca" plus an oesophageal valve are apomorphic
This might suggest that the possession of ovaries with an unpaired structure by species in the family Pyrgodesmidae is an apomorphic
condition, which probably reflects the small size of individuals in this family (< 10 mm) and their short lifespan of about 3 months (Adis et al.
Sphenisciformes is applied in a more exclusive sense to the clade including all Pansphenisciformes that share the apomorphic
loss of aerial flight.
The dorsal processes of the premaxillae are apomorphic
, being longer and more vertical than those of any extant or fossil salmonine.
The likely apomorphic
reversal of shape of the colobathristid forewings has probably co-evolved jointly with transformation of the shape of mesoscutellum.
Higher systematic placement of the material from Mene de Inciarte, Zulia State, Venezuela, to Toxodontidae is supported by apomorphic
characters preserved on the teeth.
Biramous limbs and nauplius larvae, apomorphic
characters for crustaceans, can readily be optimized on an evolutionary tree, showing students why these taxa and other crustaceans share taxonomic identity.
Thus, the presence of five stamens and five carpels is apomorphic
for subseries Pentandrae.
In fact this genus could be included within Neornithes on the basis of the following apomorphic
feature: humeral articular surface not extended sternally beyond the omal margin of the scapular cotyla (see figure 3).
The number of states per character ranged from 2 to 7, and the total number of apomorphic
states was 80.
Determining what are plesiomorphic and what are apomorphic
states is central to phylogenetic systematics and is termed character polarisation (Cameron and Groves 2004: 107).
These characters were considered apomorphic
by Silva (2004).
Subsequently, Lindberg (1998) treated it as the most apomorphic
family in Acmaeoidea; more recently, Waren & Bouchet (2005) have reinstated it at a higher level and have recognized it as the superfamily Neolepetopsoidea.
We may conclude that Eisenia foetida spermatozoon is of a apomorphic
type since it presents several evolved characteristics such as: a very large acrosome; the primary acrosomic vesicle is held within the acrosomal tube, the axial rod is very elongated and ended in a developed capitulum and a number of mitochondria of the midpiece equal to six.