Gray/Cope's Gray Treefrog Hyla versicolor/chrysoscelis  
Kingdom Animalia   >   Phylum Chordata   >   Class Amphibia   >   Order Anura   >   Family Hylidae   >   Genus Hyla   

Status:

Cope's Gray Treefrog (Hyla chrysoscelis) and Gray Treefrog (Hyla versicolor) are identical in external appearance. Cope's Gray Treefrog is much more common than Gray Treefrog on the coastal plain, while Gray predominates to the west. Despite their extreme similarity, there is no interbreeding between the two species. H. chrysoscelis is diploid, and has a total of 24 chromosomes. H. versicolor is tetraploid, with 48 total chromosomes. Aside from the genetic differences, the vocalizations differ as well, and are the only way to differentiate the two species in the field. H. versicolor gives a slower, lower-pitched musical trill, while the call of H. chrysoscelis is faster, and harsher (Conant & Collins, 1998; Virginia Herpetological Society site). Both species call somewhat slower in colder conditions. H. chrysoscelis essentially replaces H. versicolor on the coastal plain. That said, recent MARA data proves that line is not as clear cut, and there appears to be some overlap.

Description:

Only safely differentiated in the field by voice, as both species of gray treefrogs are visually identical. They are grayish or greenish, mottled treefrogs, with variegated, lichen-like patterning, and large toe pads. There is a yellow wash on the inner surface of the hind leg. Typically, there is a pale spot below the eye.

There are 27 records in the project database.

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A Gray Treefrog species in Cecil Co., Maryland (9/20/2017). Photo by Shannon Schade. (MBP list)

A Gray/Cope's Gray Treefrog in Anne Arundel Co., Maryland (6/27/2018). Photo by Bob Cammarata. (MBP list)

A Gray/Cope's Gray Treefrog in Howard Co., Maryland (9/2/2018). Photo by Emily Carter Mitchell. (MBP list)

Gray/Cope's Gray Treefrog in Anne Arundel Co., Maryland (4/30/2005). Photo by Janice Browne. (MBP list)


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