Southern Leopard Frog

Rana sphenocephala Cope (Rana virescens sphenocephala Cope.)

Colour: Green or brown, but more often a combination of the two, with one colour abruptly invading the other in irregular fashion. Sometimes grey or fawn colour. Green or brown spots (small, irregular, or rounded), arranged in two irregular rows between the lateral folds, and still more irregularly on the sides. Spots usually not surrounded by light rings. Lateral folds light green, golden, or bronze. This colour of the lateral folds continues forward over the eye and along the canthus rostralis to the end of the muzzle. Also light metallic lines along the jaw from the shoulder to the end of the muzzle. These four converging colour lines meet in acute angles at the end of the muzzle. Eye golden or bronze, with a dark line through it. Ear bronze, with a white circular spot at its centre (not an irregular blotch, such as may be present in Rana pipiens. Upper and lower lips dark, conspicuously spotted with white. Legs barred or spotted.) (These bands or spots may be edged with light.) Arms conspicuously spotted. Usually a dark band on the front of the humerus; also on the front of the femur Concealed part of femur dark in colour, with yellow or white spots or reticulations. Underparts glistening white, yellow posteriorly. The throat and breast may be distinctly or obscurely mottled with brown. Whole frog iridescent.
Measurements: Size medium, i.e. 2 1/2 to 3 1/2 inches. Head long, its length contained two and a half times in the total length of head and body. Leg long, its length to the heel exceeding the length of the body forward to the end of the muzzle. Tibia much longer than femur.
Structure: Skin relatively smooth, very finely tubercular on back, sides, and tibiae. Tibia may be ridged lengthwise. More or less unbroken lengthwise folds of skin--four in number--between the prominent lateral folds. Glandular fold along jaw to shoulder. Head narrow, pointed.
Range: Rana sphenocephala is common in the Austroriparian subregion. It is reported from Georgia (Nashville, Saint Simon's Island, Liberty County), Florida (Georgiana, Ozona, Fort Myers, Seven Oaks), Louisiana (Prairie mer Rouge, New Orleans), and Texas (Hitchcock). One specimen is reported also from Wheatland, in southern Indiana.

Eyes large; space between them narrow. Nostrils round, below the line of the prominent canthus rostralis, much nearer to the end of the muzzle than to the eye. Ear smaller than eye. Feet long, webs deeply indented. Fingers and toes long and slender. A tarsal ridge, and outer and inner sole tubercles are present. Thumb of male thickened at base.

The Southern Leopard Frog is perhaps the most beautiful frog in North America. It has not the delicate modest beauty of the Wood Frog, but it has distinction of form, richness of colouring, and intricacy of colour pattern. It has not, like the Wood Frog, an expression indicating gentleness and tameness. Instead, a creature extremely alert and wild, possessing great powers of activity, is seen in the unusually large eyes and in the attentive pose of the slender body.

The head is long and pointed, with the eyes set far back. This characteristic and the unusual length of the hind legs distinguish the frog at once from Rana pipiens, the Common Leopard Frog. It is peculiar, also, in possessing a circular white spot at the centre of the ear. This spot is never lacking, no matter what the colouration of the frog may be at the time. Rana pipiens has sometimes a light blotch at or near the centre of the ear, but never this clean-cut circle of white.

The background of colouration varies greatly, but is seldom plain green or brown. Instead, it is a mixture of the two. The colours are equally intense, and meet each other in irregular lines, without any blending. The brown is usually a warm shade, not grey or ashy, and the green is most often pure green, without an unusual amount of either yellow or blue in it. An occasional frog is found which is light yellow-green. The spots may be dark green or brown, and are not margined with light colour, except on the legs. The spots are irregular in shape and arrangement. Not only do the two sides of the frogs differ in the number, size and arrangement of the spots, but, what is more unusual, the two legs are sometimes totally different in these respects. The colouring is everywhere highly metallic in character. The changes are not especially rapid. This species of frog in Texas is often beautiful in a dress of light dove-grey or fawn-colour.

The male Rana sphenocephala has large vocal pouches, one at each side, above the arm. These frogs are wild and active. They leap long distances, and are difficult to catch. The species is evidently a very distinct one, not intergrading with Rana pipiens, but holding its own with the latter frog in the same localities in the southern part of the United States.