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| Boana platanera photo by Mateo Garcia Mejía Used under Creative Commons license granted in this iNaturalist record |
A big part of the adventure of making this blog and recording frog calls and putting together this blog is trying to identify the various frog sounds I capture. In the United States this is a pretty easy task because I know many of the calls from experience and those that I don't are readily found described in field guides and recorded online in various places.
But outside the US and Australia, it isn't as easy. Although the calls for many species are known and described in field guides or at least the scientific literature, actually getting the opportunity to hear what the call sounds like are few and far between. And for many species, the calls have never been documented. So it can take me months of reading, listening online and other detective work to ID some of my recordings (I have dozens of calls I still don't know as well!).
This recording was part of an all night recording I made at a pond at the edge of the Piedras Blancas National Park in southern Costa Rica.
Boana platanera calling from Piedras Blancas National Park, Costa Rica
After I made this recording, I was a bit confused as to the identity of this frog. I knew it didn't sound like the locally common Boana rosenbergi and I couldn't figure out what other species could sound like this. So I did some searching using online sources like xeno-canto.org, iNaturalist.org, Fonozoo.com and found the most similar call I could and that was a recording of the Emerald-eyed Treefrog (Boana crepitans).
But Boana crepitans doesn't occur in Central America; it is restricted to the Atlantic Coast of Brazil. So that led me to a taxonomic hunt using Amphibian Species of the World to find what the closest relative to B. crepitans would be in Costa Rica. That led me to Boana xerophylla which eventually led me to this paper which described a new species, Boana platanera, based on specimens from the northern part of the range of B. xerophylla.
Unfortunately, that paper described the new species as occurring in Trinidad and Tobago, Venezuela (north of the Orinoco River), northwestern Colombia and into Central Panama. But the species did not make it into Costa Rica. iNaturalist had this record from David in northern Panama which is only 50 miles from where my recording was made (although some have questioned that ID).
Here is a map taken from iNaturalist.org showing the approximate range (pink polygon) and iNaturalist records (red squares). Obviously the species is documented from outside the range shown on the iNaturalist map. The map on the IUCN Red List is more broad, but still terminates in Central Panama. This recording was made at the location indicated by the red square identified by the black arrow on this map above. It is the first record for Costa Rica, although barely into Costa Rica.
So I had to dive into the description paper to see if this could be the species in question. Fortunately, the paper had descriptions of the call and waveform diagrams and these matched my recording almost perfectly based
- their two "phases" of the call
- the number of parts to the call
- the timing of each part
- and their general description of the call.
Boana platanera calling from Piedras Blancas National Park, Costa Rica
I have subsquently listened to all the available recordings for this species on iNaturalist and they sound similar enough to confirm my identification (to me?). I can not find another species that could make a similar call that is in range.
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© Chris Harrison 2024
Escalona Sulbarán, M., E. La Marca, M. C. Castellanos-Montero, A. Fouquet, A. J. Crawford, F. J. M. Rojas-Runjaic, A. A. Giaretta, J. C. Señaris, and S. Castroviejo-Fisher. 2021. Integrative taxonomy reveals a new but common Neotropical treefrog, hidden under the name Boana xerophylla. Zootaxa 4981: 401–448 (https://doi.org/10.11646/zootaxa.4981.3.1).
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