Megatestis Donnellan, Mahony & Richards, 2025

Donnellan, Stephen C., Mahony, Michael J., Esquerré, Damien, Brennan, Ian G., Price, Luke C., Lemmon, Alan, Lemmon, Emily Moriarty, Günther, Rainer, Monis, Paul, Bertozzi, Terry, Keogh, J. Scott, Shea, Glenn M. & Richards, Stephen J., 2025, Phylogenomics informs a generic revision of the Australo-Papuan treefrogs (Anura: Pelodryadidae), Zoological Journal of the Linnean Society 204 : -

Megatestis Donnellan, Mahony & Richards , gen. nov.

( Fig. 22)

ZooBank LSID: urn:lsid:zoobank.org:act:F90744D2-FE44-49F8-8765-81A1D77F863D Type species: Chiroleptes dahlii Boulenger, 1896 .

Content: One species— Megatestis dahlii * (Boulenger, 1896) comb. nov.

Diagnosis: Megatestis can be diagnosed from the sister taxon Leptobatrachus by medium vs. long legs, undeveloped vs. expanded finger discs, and the reduced state of the m. palmaris longus vs. a multi-divided state; from Cyclorana by fully vs. minimal toe webbing, small vs. large inner metatarsal tubercles, presence vs. absence (in 13 of 14 species of Cyclorana ) of intercalary structures, and by defined vs. non-defined call duration. Refer to Tables 1 and 2.

Distribution and ecology: Semi-aquatic frogs that breed in large permanent waterbodies in grasslands and savannah forest in northern Australia.

Etymology: From the Greek μέγᾰ́ς (megas, large, mighty, marvellous) and Latin testis (the organ, itself based on the Latin noun meaning witness, in reference to the Roman legal system which permitted only males to testify; Field and Harrison 1968), referring to the spectacularly large testis to body mass ratio exhibited by this species, among the largest in the animal kingdom. The gender is masculine.

Remarks: Megatestis was included in the Litoria aurea Group of Tyler and Davies (1978). Males of Megatestis can have one of the largest relative testis masses of any animal, with values of 7.3–12.6% (Donnellan et al., unpublished data). While our data are not in accord with published values, 0.102% for M. dahlii in Byrne et al. (2002), in the absence of specimen voucher numbers in Byrne et al. (2002) we are unable to evaluate the reasons for the different observations. Currently monotypic but molecular genetic analyses indicate that Megatestis dahlii is a species complex (Donnellan and Mahony unpublished data).