The spermatozoa of Uta stansburiana and Urosaurus ornatus
show the following squamate autapomorphies: a single perforatorium
extending
anteriorly from the apical tip of the paracrystalline subacrosomal
cone;
the presence of an epinuclear electron lucent region;
intermitochondrial
dense bodies; and the fibrous sheath extending into the midpiece. The
acrosome
vesicle is flattened and concentrically zoned apically; basally it
overlies
a subacrosomal cone which invests the nuclear rostrum. A stopper-like
perforatorial
base plate, rounded nuclear shoulders and a basal nuclear fossa are
present.
The proximal centriole contains a density within its centre for
approximately
one half its length and lies at approximately 80 degrees to the distal
centriole. The two central singlets of the axoneme extend into the
short
distal centriole. A peripheral dense fibre is associated with each of
the
nine triplets of the distal centriole, and the fibre continues
posteriorly
with each of the nine doublets of the axoneme. A central fibre is
associated
with the two central singlets. All fibres are absent or vestigial at
the
level of the annulus. Mitochondria are short sinuous with a maximum of
eight seen in transverse section. Uta and Urosaurus
sperm
differ from each other in their arrangement of intermitochondrial dense
bodies in two ways: 1) longitudinally, Uta has five incomplete
'rings'
of dense bodies, whereas Urosaurus has only four such rings; 2)
in cross section, each individual 'ring' of Uta may contain up to four
irregularly spaced dense bodies, whereas Urosaurus contains a
maximum
of only two dense bodies. The sperm of Uta and Urosaurus
show strong similarities to those of the agamids and polychrotids. No
spermatozoal
autapomorphies for the Phrynosomatidae were found.