Pogona barbata, a large lizard that inhabits the open woodlands of eastern
Australia, has been reported to have a high annual reproductive output, whi
ch is contrary to expectations for a large lizard. To better understand thi
s anomaly, its reproductive cycle and morphology were investigated. Males w
ere spermatogenic year round, with only a brief period of regression in Jan
uary (late summer). Females were vitellogenic and gravid through August-Dec
ember (spring to early summer). Two or three large clutches (14-26 eggs per
clutch) were produced each breeding period. Females had two germinal beds
in each ovary, and all four actively produced eggs simultaneously. Clutches
overlapped such that the next clutch began vitellogenesis before the first
was laid. These characteristics make this species' reproductive output one
of the largest known among lizards. Reproductive females had sperm stored
in oviductal crypts, but there was no evidence of sperm storage outside the
breeding period. The short-term storage of sperm by breeding females may p
romote sperm competition between males.