Frog Blog

June 2024 additions from Panama

Tatayo's Glass Frog (Hyalinobatrachium tatayoi)

Spent a couple of weeks in Panama during the summer of 2024. I went on the Canopy Family Herpetology at the Isthmus tour, which was great. Of the 37 species of anurans we encountered, I was able to record at least 22 species. Of those, at least 13 species were new to my recording lifelist including:

Panamanian Granular Toad (Rhinella centralis)
Columbian Four-eyed Frog (Pleurodema brachyops)
Striped Rocket Frog (Allobates talamancae)
Tatayo's Glass Frog (Hyalinobatrachium tatayoi)
Emerald Glass Frog (Espadarana prosoblepon)
Vicente's Poison Frog (Oophaga vicente)
Rainforest Rocket Frog (Silverstoneia flotator)
Pratt's Poison Frog (Colostethus pratti)
Spotted Foam-nest Frog (Leptodactylus insularum)
Slim-fingered Rainfrog (Craugastor crassidigitus)
Banded Robber Frog (Pristimantis taeniatus)
Panamanian Snouted Treefrog (Scinax altae)
Panama Humming Frog (Elachistocleis panamensis)
and maybe a new Tink Frog species (Diasporus sp.) - still working on identifying these!

I also added new recordings of some species I had already recorded, including:

Granular Glass Frog (Cochranella granulosa)
Rosenberg's Gladiator Frog (Boana rosenbergi)
Harlequin Treefrog (Dendropsophus ebraccatus)
Yellow Treefrog (Dendropsophus microcephalus)
Sabinal Frog (Leptodactylus melanonotus)
Mexican White-lipped Frog (Leptodactylus fragilis)
Northern Smokey Jungle Frog (Leptodactylus savagei)
Tink Frog (Diasporus diastema)
Túngara Frog (Engystomops pustulosus)

Over the next few weeks, I will be working on getting these new entries online.

________________________________________________

So my recording lifelist is now at 127 species, in 44 genera, and 15 families.

Family	Genus	Species recorded
Bufonidae
	Anaxyrus	9
	Incilius	3
	Rhinella	3

Hylidae
	Acris	3
	Boana	2
	Dendropsophus	2
	Hyla	8
	Pseudacris	6
	Osteopilus	1
	Scinax	4
	Smilisca	2
	Triprion	1

Pelodryadidae
	Litoria	9
	Nyctimystes	1
	Ranoidea	8

Microhylidae
	Austrochaperina	2
	Elaschistocleis	1
	Hypopachus	1
	Gastrophryne	2

Myobatrachidae
	Crinia	2
	Limnodynastes	1
	Platyplectrum	1
	Uperoleia	2

Craugastoridae
	Craugastor	3
	Pristimantis	2

Eleutherodactylidae
	Diasporus	1
	Eleutherodactylus	9

Centrolenidae
	Espadarana	1
	Hyalinobatrachium	4
	Cochranella	1
	Teratohyla	1

Leptodactylidae
	Leptodactylus	7
	Engystomops	1
	Pleurodema	1

Ranidae
	Lithobates	9

Dendrobatidae
	Colostethus	1
	Oophaga	2
	Silverstonia	1

Hemiphractidae
	Flectonotus	1

Aromobatidae
	Allobates	1
	Mannophryne	2

Rhinophrynidae
	Rhinophrynus	1

Scaphiopodidae
	Scaphiopus	2
	Spea	2

Panamanian Humming Frog
Elachistocleis panamensis

The Panamanian Humming Frog (Elachistocleis panamensis) is an odd, pointy-nosed microhylid that occurs from central Panama into the lowlands of Colombia and Venezuela. It is related to our North American Narrow-mouthed Toads (Gastrophryne sp.).

range map derived from iNaturalist.org (2024)

They are generally dark with a brownish-yellow back and an irregular, dark mid-dorsal stripe. The mid-dorsal stripe is split by a thin yellow line from the tip of the pointy nose to the end of the body.

The common name "humming frog" is derived from the calls of other members of this genus in South America whose calls are reminiscent of a humming sound. But this northernmost representative of the genus has a completely different type of call. The call of the Panamanian Humming Frog is more of a high-pitched whistled trilling sound. It reminds me somewhat of the high-pitched trill of the Australian Rain Frog (Austrochaperina pluvialis)

I heard these frogs calling from a flooded grassy ditch after some heavy rains in the Tocumen marshes of Central Panama. The call of this species is fairly high pitched for a frog. Because of the high pitch of this trill, I assumed it was an insect until I got home and did some research. (The sharp "chick" calls you hear among the Humming Frog calls are part of the call of the Túngara Frog. I filtered out the descending parts of the call to bring out the Humming Frog.)

Panamanian Humming Frog call

You can see in this spectrogram how there are 12 rapid high-pitched (5 kHz) chirps in less than half a second.

___________________

iNaturalist. https://www.inaturalist.org/ Accessed August 12, 2024

Panamanian Granular Toad
Rhinella centralis

The Panamanian Granular Toad (Rhinella centralis) is a small flat-headed toad restricted to Panama. It used to be considered the same species with the widespread South American Granular Toad (R. granulosus) but it was elevated to its own species in 2009.

Range map from iNaturalist.org (2024)

When I read about these toads and saw pictures of them, for some reason I thought they would be medium to large sized toads since many Rhinella species are very large. I was rather surprised when I found these toads along a dirt road through the Tocumen Marshes in Central Panama just how small they were.

As you would expect for a toad of this size, it's call is a high pitched trill lasting around 3-4 seconds and with a carrier frequency (dominant pitch) of around 2.5kHz. In general pitch, it reminded me of the call of the North American Red-spotted Toad (Anaxyrus punctatus), although that species has a longer trill.

Here's a couple of Panamanian Granular Toads calling next to each other in the Tocumen Marshes -

Panamanian Granular Toads calling

As so often happens when you are trying to record one species of frog, another species right next to it pipes in and makes it hard to get the recording of your target species. That's what happened in this recording. I was trying to record a Colombian Four-eyed Frog (Pleurodema brachyops - the hollow "ponk, ponk") when a couple of Panamanian Granular Toads started calling right next to them, and then a Tungara Frog (Engystomops pustulosus) added its "toy ray gun" "PEUW" song to ruin my recording.

Panamanian Granular Toad with its neighbors

___________________
© Chris Harrison 2024

iNaturalist. Available from https://www.inaturalist.org. Accessed August 12, 2024

Narvaes, P., and M. T. Rodrigues. 2009. Taxonomic revision of Rhinella granulosa species group (Amphibia, Anura, Bufonidae), with a description of a new species. Arquivos de Zoologia. São Paulo 40: 1–73.

Colombian Four-eyed Frog
Pleurodema brachyops

The Colombian Four-eyed Frog (Pleurodema brachyops) is a small chubby "toad-like" frog found from Central Panama down into Colombia, Venezuela and across the northern part of the Guyanan Shield.

range map derived from iNaturalist.org (2024)

Although they look somewhat similar to the Spadefoots of North America, they are actually more closely related to the widespread South and Central American "White-lipped Frogs" (Leptodactylidae).

They get their common name four-eyed from from an unusual defensive behavior. When threatened, they point their broad nose down, raising their hind legs and show enlarged "eye-spots" on the rear of their torso to the prospective predator. It is assumed the eye spots contrasting with the bright red thighs attract the attention of a predator, making the predator think they are a much larger animal. Here's a photo of the posterior side of a calling frog showing the contrasting dark spots on the rear of the body.

Photo by Miguel Diaz Anaya

used under Creative Commons License granted in this iNaturalist record.

The call of the Colombian Four-eyed Frog is a nasal honking sound. The calls are made from shallow puddles in grassy areas after rains.

Colombian Four-eyed Frog calls

As I was trying to record this Four-eyed Frog calling, a couple of other species were calling next to it making it hard to isolate the target species. You can hear the honking of the four-eyed frogs along with the "ray-gun peuw" calls of the Tungara Frog (Engystomops pustulosus) and the loud trill of the Panamanian Granular Toad (Rhinella centralis).

Colombian Four-eyed Frog and friends

___________________
© Chris Harrison 2024

iNaturalist available at https://www.inaturalist.org/. Accessed August 12, 2024.

Panama Snouted Treefrog
Scinax altae


Panama Snouted Treefrog photo by Angel Sosa-Bartuano. Used under CC-by-NC license granted on this iNaturalist record.

The Panama Snouted Tree Frog (Scinax altae) is a small, striped cone-nosed treefrog of the grasslands and marshes of the Pacific versant of Panama and into SW Costa Rica. It appears to be a southern, isolated sister population of the widespread Stauffer's Treefrog (S. staufferi) which occurs in Northwestern Costa Rica and north into Mexico.

I recorded these frogs in Central Panama just east of the Tocumen International Airport. In fact, you can hear a plane taking off in the recording!

It had rained heavily earlier that day and the frogs were calling from some flooded marshy pastureland after dark. When I first heard their buzzy call, it reminded me of a Scinax species, but I couldn't match it to any particular species I knew. It sounded like S. staufferi, but I knew that species wasn't found in Panama. I decided they must be Yellow Treefrog species (genus Dendropsophus).

It was only after I got this record uploaded to iNaturalist that another user pointed out the correct species identification. A little research online and I ended up with another new frog for the lifelist! And a new Scinax to boot - one of my favorite Neotropical hylids.

Panama Snouted Treefrog call

___________________

Barrio-Amoros, C., Forero-Cano, A.M., Stuster, R., Batista, A., Canzoneri, M., and Arias, E. 2023. The presence of Scinax altae (Dunn, 1933) in Costa Rica, with redescription of its advertisement call. Anartia 37:34-46. https://zenodo.org/records/10516165

Spotted Foam-nest Frog
Leptodactylus insularum

Leptodactylus insularum is known by a variety of common names, including Spotted Foam-nest Frog, Caribbean Ditch Frog, and San Miguel Island Frog. I will stick with the first name since it is the one iNaturalist uses and it makes as much sense as any.

Those other names don't work in this case because they are based on location and I recorded and photographed this species neither in the Caribbean nor on San Miguel Island. So Spotted Foam-nest Frog seems a better common name (even if a bit boring). The species epithet insularum means "off the island" and derived from the first specimens documented from Saboga Island just off the coast of Panama. They are also found on a couple of Caribbean Islands (off Nicaragua) and Trinidad and Tobago, but the bulk of this species range is on mainland Central and South America.

map from iNaturalis.org

This species used to be included in the much wider ranging species, Leptodactylus bolivianus. This species group is confusing, but at the moment Leptodactylus insularum is recognized as its own species and the northern member of the L. bolivianus group.

Although they are similar in general body morph to the northern Ranid frogs, Leptodactylid frogs don't have the typical ranid snore or chuckle to their call. Instead their calls are more often like whistled popping or bubbling sounds.

The call of this species reminds me of a child "popping" their finger out of the corner of their mouth or maybe a cork popping out of a bottle. It is a bit hard to hear in this recording because there is a background of the the upward whistled calls of the Mexican White-lipped Frogs (Leptodactylus fragilis) and the constant dry trilling of the Panamanian Granular Frog (Rhinella centralis). You also hear the faint "ray gun peow" of the Tungara Frog (Engystomops pustulosus). The Spotted Foam-nest Frog calls are the lower pitched "cork out of bottle" popping that occurs every 1 to 1.5 seconds throughout this recording.

Frog chorus with Leptodactylus insularum

In truth, I could barely make these calls out when I was out in this flooded marshy area in Central Panama. The sounds of the other species were so loud I honestly pressed record and pointed my microphone in the general direction, hoping that sound was a different species I could hear in there. Only when I got home was I able to remove some of the distracting noise and hear the Foam-nest Frogs for sure.

_____________________
© Chris Harrison 2024

iNaturalist. https://www.inaturalist.org/. Accessed August 18, 2024.

Tatayo's Glass Frog
Hyalinobatrachium tatayoi

Tatayo's Glass Frog (Hyalinobatrachium tatayoi) is a small Centrolenid Frog that lives in the tropical lowland forests from southernmost Costa Rica, down through Panama and into NW Venezuela, and western Colombia and Ecuador.

range map from iNaturalist.org

The call of the Tatayo's Glass Frog is best described as a single sharp "peep" repeated every five seconds or so. When slowed down, it sounds a bit more like a "wrree", although that discrimination is difficult in a recording. Like other Hyalinobatrachium, the call is high pitched with a carrier frequency of around 4.6-4.8 kHz.

We usually found the calling, sitting upright on a broad leaf overhanging a stream, sometimes quite high over the stream. At close range the call is very piercing and I found it hard to record them because they overpowered (clipped) my microphones in spite of using 32bit float recorder. (In hindsight, I should have backed off a bit - DOH!)

The spectrogram of this call is unremarkable, showing a short, sharp percussive call at around 4.7 kHz. It has a short "arm" after the main call, but I can't hear that in the recording, even when slowed down.

Call of Tatayo's Glass Frog from Anton Valley, Panama

___________________
© Chris Harrison 2024

iNaturalist. https://www.inaturalist.org/. Accessed August 24, 2024

Striped Rocket Frog
Allobates talamancae

Striped Rocket Frog (Allobates talamancae)

Photo by iNaturalist user "wasatch_hunter"

Used under Creative Commons License granted in this iNat record

The Striped Rocket Frog (Allomantes talamancae) is a tiny species of dart frog found Costa Rica, Panama, and then west of the Andes in western Colombia and northwestern Ecuador.

range map from iNaturalist (2024)

Even for dart frogs, these frogs are small. An adult is probably less than 1cm long and they are almost invisible hopping around on leaf litter on the forest floor.

The name "Rocket Frog" comes presumably from the ability of these little frogs to "rocket" around the forest floor under your feet. Unfortunately, this could lead to confusion with the totally unrelated "Rocketfrogs" of the genus Litoria in Australia. Unlike Allobates, the much larger Australian Litoria really do shoot off like a rocket when disturbed. The best an Allobates can muster is a few short hops, but common names are often given without much forethought?

These little frogs are quite common on the leaf litter of the forest floor in wet tropical forests in their range. But they are so small they are difficult to see as they hop around the ground. However, if you know their call, you can hear them everywhere on wet days!

One of the many remarkable things about these tiny frogs is their parental care. Females lay eggs off the ground in epiphytes and other water-holding areas on plants and trees. When the eggs hatch, the male frog will climb into the "pool" and collect the tadpoles onto their back. They then carry the larvae on their back down to a stream where they are released to continue their development. This system protects the babies when they are in their most vulnerable stage (in the egg) and gives them a much greater chance of survival. They don't have to face predators in the stream until they are mobile enough to escape and hide. It is really amazing to find one of these tiny anurans hopping around the forest floor with minuscule little tadpoles on their back!

Like many other dart frogs, this species is active day and night and calls from the forest floor much of the day. The call is a whistled double "pee-deep" call as well. These calling Striped Rocket Frogs called most of they day from the forest floor undergrowth in this area of Anton Valley, Panama.

Striped Rocket Frogs making the double "pee-deep" call

One a spectrogram of this call, you can see the two part call at around 4kHz. Each note has a slight upward slur to it.

iNaturalist. Available from https://www.inaturalist.org. Accessed August 12, 2024

Sabinal Frog
Leptodactylus melanonotus

I had originally had this frog and these calls identified as Leptodactylus poecilichilus in the field by a local "expert", but upon getting back and uploading the photos and to iNaturalist, another expert corrected the identification of the calls. That made me go back and reexamine the photo above as well, and I think I agree that these are/were Leptodactylus melanonotus.

So I lose a lifer. Sometimes learning and trying to capture frog call recordings for areas outside of the US can be a frustrating experience!

I recorded this loud chorus at the pond on our hotel grounds at Canopy Lodge in Anton Valley, Panama.

Sabinal Frog calls

iNaturalist. https:www.inaturalist.org accessed on August 15, 2024

Pratts Poison Frog
Colostethus pratti

Colostethus pratti from Colombia
Photograph by Wilmar Agudelo Sánchez
used under Creative Commons license granted in this iNaturalist record

Pratt's Poison Frog (Colostethus pratti) is another tiny striped dart frog from the neotropics. These small frogs in the genera Colostethus and Silverstonia are very similar looking and often live in the same forest habitats, hopping around in the leaf litter. They can be told apart carefully by their patterns of light striping on their dark sides, and of course, their calls.

This species is named after the Victorian British naturalist Antwerp Edgar Pratt.

Like many dart frogs, this species transports the tadpoles from the site of egg deposition (usually a water holding pool in a plant/epiphyte) to a nearby stream or puddle after that hatch.

This species appears to be almost endemic to Panama, although there are records from northwestern Colombia.

range map from iNaturalist.org

The identification of this frog call took some work. I originally posted it on iNaturalist as "frogs and toads" since I wasn't sure what it was. What you hear in my recording is several frogs calling back and forth, making a 8-10 rapid "whistled peeps" then resting for a second before calling again. There are two frogs calling back and forth.

Pratt's Frogs calling

I flagged iNat user (and neotropical frog call expert) ibanezr asking for help with the ID. He suggested Colostethus pratti. This sent me down the rabbit hole of reading everything I could dig up about the calls of various Colostethus species. Unfortunately the literature on this is tricky.

The call of C. panamensis call is described by Wells (1980) as "a whistled trill" of 2-5 notes with each note approximately 60ms long. There are approximately 25 ms between calls. I hear the call more as a series of "peeps" than a whistled trill, so I will use that terminology. What isn't clear from Well's description is that the call of C. panamensis apparently comes in repeated "clusters" of 3-5 notes, followed by a gap, then another 3-5 notes. That's not what is happening in my recording. My recording is 8-10 notes in each cluster.

For comparison, listen to this recording of C. panamensis (identified by R. Ibanez) from iNaturalist. This recording is notably higher in pitch (4.0 to 4.7 kHz with peak around 4.4 kHz) than mine, but has the peeps in groups of five.

Here is someone else's recording identified as C. pratti from iNaturalist. This recording shows a series of peeps with a dominant frequency around 3.8-3.9 Khz and with a series of 8-12 peeps per call.

The reported frequency range for each note in C. panamensis was from 3.2 and 4.5 kHz.

Colostethus pratti, on the other hand, is reported to produce around 19 pulses per second with a dominant frequency of 4.7 kHz.

Looking at the spectrogram for my recording, we can see my frog produced between 4 and 5 calls per second (actually 4.7) and the calls start off around 3.7 kHz and go up to 4.4 kHz. But the calls in my recording are not clustered in groups of 3-5.

Although my frogs calls were longer (more peeps than reported by Wells), this seems a much better match for Colostethus panamensis than C. pratti based on the "peep rate" and the frequency of the peeps. C. pratti would be much faster and higher.

You can hear a C. pratti call on the AmphibiaWeb account for the species. That recording has a series of rapidly repeating notes (i.e. more in the 19 notes per second range). But the recording on iNaturalist record sounds more similar to mine with a similar call structure but at a peep rate of 8 notes per second.

So whether mine is just a bit slower because it may have been cooler or some other mysterious reason, I guess the most parsimonious identification is Colostethus pratti?

Here is the my recording of the calls in question again from Anton Valley, Panama -

Pratt's Poison Frogs calling

___________________

Ibáñez, R.I., Griffith, E.J., Lips, K.R. & Crawford, A.J. 2017. Altitudinal distribution and advertisement call of Colostethus latinasus (Amphibia: Dendrobatidae), endemic species from eastern Panama and type species of Colostethus , with a molecular assessment of similar sympatric species. Zootaxa 4254(1): 91–101. DOI: 10.11646/zootaxa.4254.1.5

iNaturalist. https://www.inaturalist.org/. Accessed August 18, 2024

Jiménez-Bolaño, J. D., A. C. Montes-Correa, F. Leonhardt, and J. M. Renjifo. 2020. Advertisement call of Pratt’s rocket frog, Colostethus pratti, from the western Andes of Colombia (Anura: Dendrobatidae). Salamandra 56: 395–400.

Wells, K.D. Behavoral ecology and social organization of a dendrobatid frog (Colostethus inguinalis). Behav Ecol Sociobiol 6, 199–209 (1980). https://doi.org/10.1007/BF00569201

Blog Entry Categories