Nature and science

The frog whose call forced a new map

Documented history and research · Evidence reviewed

Calls and genetics exposed a species boundary that appearance alone had concealed.

A familiar-looking animal becomes a different question

After the Atlantic Coast leopard frog was formally named in 2014, researchers revisited the range of leopard frogs along the eastern seaboard. Their 2018 study combined listening surveys, genetic samples, photographs and historical records. South Jersey formed part of a regional overlap where superficially similar frogs had made older distribution maps difficult to interpret. Schlesinger and colleagues (2018).

Listening proved more dependable than one marking

Calls and genetic identifications agreed closely at the population level. No single visible character reliably separated Atlantic Coast and southern leopard frogs, although combinations of features classified more than ninety percent correctly. The newer species was associated with large coastal wetland systems; the southern leopard frog occupied a broader variety of habitats. Schlesinger and colleagues (2018).

The discovery changed the map, not the frogs

The team revised earlier range assumptions rather than documenting animals suddenly moving into every newly recognized locality. An unfamiliar name may reflect corrected identification of a long-present population. One supposedly decisive marking cannot substitute for the combined evidence establishing the species boundary. Schlesinger and colleagues (2018).

Sources and research limits

Schlesinger and colleagues (2018) — Full-text survey methods, genetics, morphology and distribution results read.

The range study does not establish occupancy throughout the central Pine Barrens.