Phyllomedusidae

Waxy monkey frogs Phyllomedusa sauvagii, copyright Brocken Inaglory.

Belongs within: Hyloidea.

Monkey frogs
Published 23 November 2019

Following my last post, it looks like we’re staying in the Neotropics for a while longer. The leaf frogs or monkey frogs of the Phyllomedusinae (a subfamily of the tree frog family Hylidae) are perhaps the most famous group of frogs to be found in South America. One particular species, the red-eyed tree frog Agalychnis callidryas, would for many people be the first image that comes to mind when they picture a frog, owing to its regular appearance in popular media.

The aforementioned red-eyed tree frog Agalychnis callidryas, copyright Carey James Balboa.

The phyllomedusines are a group of about sixty species of slender, arboreal frogs that live as ambush predators of invertebrates. The inner digits of the hands and feet are opposable and can be used to grasp slender twigs while adhesive pads at the ends of the digits allow the frog to grip onto flat surfaces such as leaves. Darren Naish at Tetrapod Zoology (Wayback Machine version; the current iteration of Tetrapod Zoology is at tetzoo.com) has described leaf frogs as superficially resembling “slow-climbing primates like lorises”. Phyllomedusines will perch with all four hands and feet firmly grasping the substrate, waiting for suitable prey to inadvertently stray too close. Prey is captured by means of a highly protrusible tongue, not found in other hylids. In at least some species, light markings are present on the outer toes which may be drummed while in ambush to attract prey. Bertoluci (2002) suggested that the movement of these light patches in Phyllomedusa burmeisteri may resemble those of a worm or caterpillar but I would suggest that merely the appearance of the small moving points alone may pique a wandering arthropod’s interest while the camouflaged remainder of the frog blends into the background.

Orange-legged tree frog Phyllomedusa oreades, copyright Danielvelhobio.

Though phyllomedusines begin their lives as aquatic tadpoles, their eggs are laid in clutches outside the water, in locations such as on leaves, tree trunks, rock crevices, etc. In some species, one or more leaves are folded together to construct a nest in which the eggs are laid. Some phyllomedusines in the genera Agalychnis and Cruziohyla are capable of gliding by means of extensive webbing on enlarged hands and feet and/or skin flaps on arms and legs. Interestingly, possession of gliding ability in phyllomedusines is correlated with explosive breeding patterns, suggesting that its main function is to facilitate synchronised movement of members of a population between their usual upper canopy habitat and suitable breeding locations near ground-level water bodies (Faivovich et al. 2009). Females of the two gliding genera (or sometimes a mating pair) may also spend time sitting in water prior to egg-laying; during this time, the female draws water into her bladder that she will then release over the eggs while laying them. In the majority of phyllomedusines (except Agalychnis) egg masses contain a mixture of eggs and empty, eggless capsules. In those species that construct nests from folded leaves, these extra capsules act as the glue holding the leaf surfaces together. Their function in other species is less obvious; they may help to protect the egg mass from drying out.

Upon hatching, the tadpoles will wriggle out of the egg mass to drop into a nearby body of water, whether a pond, a stream, or a pool of water collected in the hollow of a tree. After a childhood spent scraping algae for food, they will eventually transform into a new generation of frogs, ready to ascend once again into the trees above.

Systematics of Phyllomedusidae
<==Phyllomedusidae [Phyllomedusinae]FG06
|--+--Phrynomedusa Miranda-Ribeiro 1923DMH16, FG06
| | `--P. marginataPW11
| `--Cruziohyla Faivovich et al. 2005DMH16, FG06
| `--C. calcariferFG06
`--+--Hylomantis Peters 1873DMH16, FG06
| |--+--*H. asperus Peters 1873DMH16
| | `--H. granulosusDMH16
| `--+--Pachymedusa Duellman 1968PW11, FG06
| | `--P. dacnicolorFG06
| `--Agalychnis Cope 1864PW11, FG06
| | i. s.: A. buckleyi [=Phyllomedusa buckleyi]DMH16
| | A. danieliDMH16
| | A. helenaeF15
| | A. medinaeDMH16
| | A. psilopygionDMH16
| |--A. hulliDMH16 [=Hylomantis hulliPW11]
| `--+--A. lemurDMH16 [=Hylomantis lemurPW11]
| `--+--A. dacnicolorDMH16
| `--+--+--A. litodryasPW11
| | `--A. spurrelliDMH16
| `--+--A. saltatorDMH16
| `--+--+--*A. callidryas Cope 1852DMH16
| | `--A. terranovaDMH16
| `--+--A. annaeDMH16
| `--A. moreletiiPW11
`--+--Phasmahyla Cruz 1991FG06
| |--P. jandaiaPW11
| `--+--P. exilisPW11
| `--+--P. cochranaeDMH16
| `--+--P. cruziDMH16
| `--P. guttataDMH16
`--+--Phyllomedusa Wagler 1830PW11, FG06
| | i. s.: P. coelestisDMH16
| | P. venustaDMH16
| |--+--*P. bicolor (Boddaert 1772)DMH16, PW11, DMH16 [=Rana bicolorDMH16]
| | `--P. vaillantiPW11
| `--+--+--P. cambaPW11
| | `--+--P. tarsiusPW11
| | `--+--P. neildiPW11
| | `--P. trinitatisPW11
| `--+--P. bolivianaPW11
| `--+--P. sauvagiiPW11
| `--+--P. bahianaDMH16
| `--+--P. burmeisteriDMH16
| `--+--P. iheringiiDMH16
| `--+--P. distinctaPW11
| `--P. tetraploideaPW11
`--+--Callimedusa Duellman, Marion & Hedges 2016DMH16
| |--C. tomopternaDMH16 [=Phyllomedusa tomopternaPW11]
| `--+--C. atelopoidesDMH16 [=Phyllomedusa atelopoidesPW11]
| `--+--+--*C. perinesos (Duellman 1973) [=Phyllomedusa perinesos]DMH16
| | `--C. ecuatorianaDMH16
| `--+--C. balteaDMH16 [=Phyllomedusa balteaPW11]
| `--C. duellmaniDMH16 [=Phyllomedusa duellmaniPW11]
`--Pithecopus Cope 1866DMH16, FG06 [Pithecopinae]
|--+--P. palliatusDMH16 [=Phyllomedusa palliataPW11]
| `--+--P. nordestinusDMH16 [=Phyllomedusa nordestinaPW11]
| `--+--*P. azureus (Cope 1862) [=Phyllomedusa azurea]DMH16
| `--P. hypochondrialisDMH16 [=Phyllomedusa hypochondrialisPW11]
`--+--P. megacephalusDMH16 [=Phyllomedusa megacephalaPW11]
`--+--P. rohdeiDMH16 [=Phyllomedusa rohdeiPW11]
`--+--+--P. ayeayeDMH16 [=Phyllomedusa ayeayePW11]
| `--‘Phyllomedusa’ itacolomiPW11
`--+--P. centralisDMH16 [=Phyllomedusa centralisPW11]
`--+--‘Phyllomedusa’ araguariPW11
`--P. oreadesDMH16 [=Phyllomedusa oreadesPW11]

*Type species of generic name indicated

References

Bertoluci, J. 2002. Pedal luring in the leaf-frog Phyllomedusa burmeisteri (Anura, Hylidae, Phyllomedusinae). Phyllomedusa 1 (2): 93–95.

[DMH16] Duellman, W. E., A. B. Marion & S. B. Hedges. 2016. Phylogenetics, classification, and biogeography of the treefrogs (Amphibia: Anura: Arboranae). Zootaxa 4104 (1): 1–109.

Faivovich, J., C. F. B. Haddad, D. Baêta, K.-H. Jungfer, G. F. R. Álvares, R. A. Brandão, C. Sheil, L. S. Barrientos, C. L. Barrio-Amorós, C. A. G. Cruz & W. C. Wheeler. 2010. The phylogenetic relationships of the charismatic poster frogs, Phyllomedusinae (Anura, Hylidae). Cladistics 26: 227–261.

[F15] Fowler, H. W. 1915. Cold-blooded vertebrates from Florida, the West Indies, Costa Rica, and eastern Brazil. Proceedings of the Academy of Natural Sciences of Philadelphia 67 (2): 244–269.

[FG06] Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. B. Haddad, R. O. de Sá, A. Channing, M. Wilkinson, S. C. Donnellan, C. J. Raxworthy, J. A. Campbell, B. L. Blotto, P. Moler, R. C. Drewes, R. A. Nussbaum, J. D. Lynch, D. M. Green & W. C. Wheeler. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History 297: 1–370.

[PW11] Pyron, R. A., & J. J. Wiens. 2011. A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of extant frogs, salamanders, and caecilians. Molecular Phylogenetics and Evolution 61: 543–583.

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