ECOLCOY, SYSTEMATICS AND EVOLUTION OF AUSTRALIAN FROGS 59
Rpecim, the rangc of C. subin,qigniferu is entirely contained within that
of C. pxedinsiynifera which live nnd hood in the same place. Counts
and othar menHuro’On of uhuntlaric~ have not proved practicable and so
it in not known what competitive dinplacement, if any, occurs when
C. pseudineignif~ru and C . eubinsigniJeru OCCUF together.
The contiguous distribution of C . insignifera and C . peeudinsignifera
appears to be related to the duration of larval life (short in C. pseudineignifera) ; temperature of water for larval development (hotter in
C. psew/i?LYignqern); and mean breeding temperature (low in C . pseudinsignifera). These rather unusual conditions arise because of the coastal
distribution of C. insignifera where madime conditions lead to cloudiness, warmer night temperatures, and higher rainfall. Conversely, the
inland condit.ions lead to reduced cloudiness, colder nights, sunny days
and warmer daytime pond temperatures. From the evolutionary interpretation developed in Section IV it would seem that the different
habitat preferences shown by the foregoing species of Crinia have
arisen largely as a consequence of their evolution during the
Pleistooene.
Main (1957) identified two races of C. insignijera by the male
breeding call. The “clay” race occupies a piedmont zone along the
coastal side of the Darling fault scarp, while the “sand” race occupies
interdune swamps of a series of coastal dunes originating at times of
changing sea level during the Pleistocene. The clays and sands interdigitate in localities where sand has blown over the clays but generally
there is a clear separation along a north-south line. When the mean
breeding temperature is calculated for the “clay” race (defined as
occurring in clay swamps) and “sand” race (defined by sand bottom of
swamp and adjacent sand hills) it is found to be 14-0”C for the “clay”
race ( 7 i observations) and 12.7”C for the “sand” race (138 observations) (Main, unpublished).
Field observations over a number of years show that when winter
rains bcgin, the two sorts of swamp fill differently - those on clay fill
with the first rains while sand swamps may take many weeks before the
sand is saturated and water lies in the swamps. The “clay” race breeds
as soon P,S rains begin and in many places, after the first few nights,
females are not seen for the remainder of the season. The “sand” race
does not breed until free water is present, conRequently it is later in the
season and colder as shown by the lower mean breeding temperature of
this race. A more important difference between the races is that whereas
the breeding of the “clay” race is almost a single episode, that of the
“sand” race may occur after most rain showers during the winter.
In spring, as the heavy winter rains cease, and especially in years of
below average rainfall, the swamps And ponds on clay quickly dry up.
Rpecim, the rangc of C. subin,qigniferu is entirely contained within that
of C. pxedinsiynifera which live nnd hood in the same place. Counts
and othar menHuro’On of uhuntlaric~ have not proved practicable and so
it in not known what competitive dinplacement, if any, occurs when
C. pseudineignif~ru and C . eubinsigniJeru OCCUF together.
The contiguous distribution of C . insignifera and C . peeudinsignifera
appears to be related to the duration of larval life (short in C. pseudineignifera) ; temperature of water for larval development (hotter in
C. psew/i?LYignqern); and mean breeding temperature (low in C . pseudinsignifera). These rather unusual conditions arise because of the coastal
distribution of C. insignifera where madime conditions lead to cloudiness, warmer night temperatures, and higher rainfall. Conversely, the
inland condit.ions lead to reduced cloudiness, colder nights, sunny days
and warmer daytime pond temperatures. From the evolutionary interpretation developed in Section IV it would seem that the different
habitat preferences shown by the foregoing species of Crinia have
arisen largely as a consequence of their evolution during the
Pleistooene.
Main (1957) identified two races of C. insignijera by the male
breeding call. The “clay” race occupies a piedmont zone along the
coastal side of the Darling fault scarp, while the “sand” race occupies
interdune swamps of a series of coastal dunes originating at times of
changing sea level during the Pleistocene. The clays and sands interdigitate in localities where sand has blown over the clays but generally
there is a clear separation along a north-south line. When the mean
breeding temperature is calculated for the “clay” race (defined as
occurring in clay swamps) and “sand” race (defined by sand bottom of
swamp and adjacent sand hills) it is found to be 14-0”C for the “clay”
race ( 7 i observations) and 12.7”C for the “sand” race (138 observations) (Main, unpublished).
Field observations over a number of years show that when winter
rains bcgin, the two sorts of swamp fill differently - those on clay fill
with the first rains while sand swamps may take many weeks before the
sand is saturated and water lies in the swamps. The “clay” race breeds
as soon P,S rains begin and in many places, after the first few nights,
females are not seen for the remainder of the season. The “sand” race
does not breed until free water is present, conRequently it is later in the
season and colder as shown by the lower mean breeding temperature of
this race. A more important difference between the races is that whereas
the breeding of the “clay” race is almost a single episode, that of the
“sand” race may occur after most rain showers during the winter.
In spring, as the heavy winter rains cease, and especially in years of
below average rainfall, the swamps And ponds on clay quickly dry up.