Frog of the Week

Paradoxical Frog (Pseudis paradoxa)

Paradoxical Frog
photo by Hans Hillewaert
least concern

Common Name: Paradoxical Frog, Paradox Frog, Shrinking Frog
Scientific Name: Pseudis paradoxa
Family: Hylidae – Tree Frog Family
Locations:  Argentina, Bolivia, Brazil, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela
Size: 1.7 – 3 inches (45 – 75 mm)

The Paradoxical Frog is named after a strange phenomenon during their metamorphosis. Their tadpole is the largest tadpole in the world, almost reaching 10 inches (25 cm) long! That is over three times larger than the length of an adult frog! What a paradox! Yet, not all tadpoles exhibit the paradox. Tadpoles that are born in temporary bodies of water with predators transform quickly and leave the water before they get to massive sizes. In permanent bodies of water, they transform slower, thus allowing more growth time.

The Paradoxical Frog is a member of the Tree Frog family – Hylidae but they are never seen in the trees. They live in and around permanent and temporary ponds. These are the same bodies of water that they breed in. The males will call for the ponds for the females. Once the female arrives, the male will grasp her from behind in the amplexus position. Then, the female will start laying her eggs and the male will fertilize them. The eggs are laid in the vegetation near the shore. Neither parent provides any parental care.

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Paradoxical Frog as Least Concern for Extinction. They have a wide spread range and are common throughout it. Some populations are facing declines due to habit loss due to urban development and agriculture.

Frog of the Week

Hurter’s Spadefoot Toad (Scaphiopus hurterii)

Common Name: Hurter’s Spadefoot Toad
Scientific Name: Scaphiopus hurterii
Family: Scaphiopodidae – American Spadefoot Toad family
Locations: United States and Mexico
US Locations: Texas, Louisiana, Arkansas, and Oklahoma
Size: 1.75 – 3.25 inches (4.4 – 8.3 cm)

The Hurter’s Spadefoot Toad is named after naturalist Julius Hurter, former curator of the St. Louis Academy of Science. They were once considered a subspecies of the Eastern Spadefoot Toad but was moved to being a full species. Like all Spadefoot Toads, the Hurter’s Spadefoot Toad is mostly fossorial, spending most of its time in burrows underground. They have keratonized sheaths on their rear feet that they use to help dig. Spadefoot toads can be distinguished from other groups of toads due to their vertical, cat-like eyes.

The easiest time to find a Hurter’s Spadefoot Toad is during the breeding season from late spring into summer. They breed following heavy storms that fill up temporary pools of water. Mating only lasts a day or two so you need to get out there quick. The males will call out from the shallows of the pools to attract a mate. Once the mate arrives, the male will grasp her from behind in the amplexus position. Then, the female will lay her eggs and then the male will fertilize. Neither parent provides any care for the offspring.The eggs hatch in 48 hours and the tadpoles complete their metamorphosis in two weeks. This is due to the limit time they have before the pond dries up. Surprisingly, the tadpoles will eat each other if there isn’t enough food in the ponds.

Frog of the Week

Tarahumara Frog (Rana tarahumarae)

Tarahumara Frog
photo by Jim Rorabaugh of USFWS

Common Name: Tarahumara Frog
Scientific Name: Rana tarahumarae
Family: Ranidae – True Frog family
Locations: United States and Mexico
US Locations: Arizona
Size: 2.5 – 4 inches (64 – 102 mm)

The Tarahumara Frog is found in the montane canyons of southern Arizona and down into Mexico. Their main habitat is rocky streams and plunge pools. They breed in these permanent bodies of water from April to May. The male frog will call out to the females though they lack vocal sacs like other frogs have. The female will arrive and the male will grasp her from behind in the amplexus position. Then, the female will lay her eggs and the male will fertilize them. Females can lay up to 2200 eggs at a time. Neither parent will provide any parental care for their offspring. The tadpoles can take over 2 years to complete their metamorphosis.

The International Union for the Conservation of Nature (IUCN) Red Lists categorizes the Tarahumara Frog as Vulnerable to Extinction. The frog is extinct in Arizona and is steadily disappearing from Mexico. Chytrid Fungus, a deadly disease, is believed to have caused large die offs of the frogs. Other reasons for the declines in their numbers include invasive species, pollution, and habitat destruction. Invasive species, such as the Blue Gill and American Bullfrog, feast upon the frog and their tadpoles. Much of the range of the Tarahumara Frog in Arizona has been taken over by Bullfrogs.

There are currently projects working to reintroduce the frogs into Arizona. The first reintroduction was done in 2004. All of the frogs sadly died out over the next 10 years due to Chytrid Fungus and flooding. In 2012 and 2013, frogs and tadpoles were once again reintroduced but a die off happened due to chytrid fungus again. There’s still hope enough survived to continue the population. More plans for reintroduction are being considered.

Frog of the Week

Green and Golden Bell Frog (Litoria aurea)

photo by LiquidGhoul

Common Name: Green and Golden Bell Frog
Scientific Name: Litoria aurea
Family: Hylidae – True Frog family
Locations: Australia
Introduced Locations: New Caledonia, New Zealand, and Vanuatu
Male Size: 2.2 – 2.7 inches (57 – 69 mm)
Female Size: 2.5 – 4.2 inches (65 – 108 mm)

While the Green and Golden Bell Frog is a member of the tree frog family, they are a semi-aquatic species of frog. They like to perch on vegetation around water. The frogs breed during summer time from October through March. Reproduction is pretty standard for these fellas. The males will call from the water and the female will select a mate. Then the male will grasp her from behind in the amplexus position and she will lay her eggs. The female frog lays between 3 – 10 thousand eggs. The male will then fertilize the eggs. Neither parent provides any care for their offspring.

The Green and Golden Bell Frog is naturally found along the southeastern coast of Australia but has expanded its range to other Pacific Islands including New Zealand. In New Zealand, they are found on the northern half of North Island. It’s hard to tell if these frogs are causing any problems in these new habitats.

The Green and Golden Bell Frog is listed as Vulnerable by the International Union for the Conservation of Nature (IUCN) Red List. The frogs face a variety of threats. The wetlands that the frogs live in are being drained to make room for more houses. The Mosquito Fish (Gambusia holbrooki) has been introduced to the wetlands as well to control mosquito populations. Sadly, these fish also feed on tadpoles of frogs. Also Red Foxes (Vulpes vulpes) has been introduced to Australia and they can feed on adult frogs. Chytrid Fungus, a deadly fungal pathogen that is devasting frog populations around the world, has been found in the frogs. This is likely causing some declines in the species.

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Smooth Newt (Lissotriton vulgaris)

photo by John Beniston

Common Name: Smooth Newt
Scientific Name: Lissotriton vulgaris
Family: Salamandridae
Locations: Albania, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Kazakhstan, Latvia, Lithuania, Luxembourg, Macedonia, Moldova, Montenegro, Netherlands, Norway, Poland, Romania, Russia Serbia, Slovakia, Slovenia, Sweden, Switzerland, Turkey, Ukraine, and United Kingdom
Introduced Locations Australia
Size: 3.9 inches (10 cm)

The Smooth Newt is one of the most common amphibians found throughout temperate, forest areas in Europe. They are mostly terrestrial, only staying in water for extended periods of time during breeding season. They are also nocturnal, spending their days under logs and rocks. The newts do come out during rains during the day.

The Smooth Newt reproduces after the newt wake up from hibernation. The males and females move to ponds to breed. The males will grow out a wavy crest on their back to impress the females. The male will do a courtship dance to attract females. The males will deposit a sperm packet in the water and will lead a female over it during the courtship. The female will pick it up with her cloaca and bring it inside her to fertilize her eggs. A few days layer, the female will lay her eggs, as many as 300. Eggs hatch a few weeks later and larvae will appear. The larvae take a few months to complete their metamorphism, but some individuals may take over a year. These individuals will then have to survive in the water over winter.

In Australia, the Smooth Newt has established populations in the wild. It is believed the newts were released into the wild from a pet owner who didn’t want them anymore. Never do that please. Currently, it is not known if the newt is causing any serious environmental problems so the Australian Government isn’t actively trying to prevent their spread or eliminate them.

Frog of the Week

Marsh Frog (Pelophylax ridibundus)

photo by Charles J Sharp

Common Name: Marsh Frog
Scientific Name: Pelophylax ridibundus
Family: Ranidae – True Frog Family
Locations: Afghanistan, Albania, Armenia, Austria, Azerbaijan, Bahrain, Belarus, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iran, Islamic Republic of, Iraq, Israel, Italy, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Macedonia, Moldova, Montenegro, Netherlands, Poland, Romania, Russia, Saudi Arabia, Serbia, Slovakia, Slovenia, Tajikistan, Turkey, Turkmenistan, and Ukraine.
Introduced Locations: Belgium, Spain, Switzerland, and the United Kingdom
Female Size: 6.7 inches (17 cm)
Male Size: 4.7 inches (12 cm)

The Marsh Frog is the largest frog native to Europe. Its found around the edges of rivers, lakes, ponds, and streams. They rarely ever move away from these shores. The frogs will start to breed at the beginning of spring. Like most frogs, the male Marsh Frogs will call to the female frogs from the shallows of the water. Once the female selects a mate, the male frog will grasp her from behind. The female will then lay her eggs and the male will then fertilize them. The female can lay between 670-13,000 eggs. Neither parent will provide any care for their offspring.

Marsh Frogs were introduced to Kent, England in the 1930s. Other populations of the frog have popped up in western London and the southwestern part of the country. Due to their size, they prey on native wildlife, potentially having problematic effects on the native populations. The frogs could also be spreading chytrid fungus, a deadly pathogen, around the country.

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Invasive Species Week

It is National Invasive Species Week! The week was created to raise awareness for the problems that invasive species create. What is an invasive species? It is a non-native living organism that has been introduced to a new environment by humans that is likely to cause economic harm, environmental harm or harm to human health. Invasive species can be fish, plants, insects, fungus, bacteria, and everything in between.

This week I will highlight invasive species that are causing problems, mostly for amphibians, here and on my social media accounts. Please stay tuned for more!

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Pacific Tree Frog (Pseudacris regilla)

photo by The High Fin Sperm Whale 

Common Name: Pacific Tree Frog, Pacific Chorus Frog
Scientific Name: Pseudacris regilla or Hyliola regilla
Family: Hylidae – Tree Frog family
Locations: Canada, Mexico, and the United States
US Locations: Alaska, Arizona, California, Idaho, Montana, Nevada, Oregon, Utah, and Washington
Size: .75 – 2 inches (19 – 50 mm)

Breeding for the frogs happen from November to July with frogs in higher elevations breeding later in the year. The male frogs will come to permanent or non-permanent waters bodies to start calling. The male frog’s breeding call is the typical ribbit that you hear on tv.

The males will highly territorial and will fight other males over breeding areas. Once the female comes and selects a mate, the male will grab her back in amplexus. The female will then lay her eggs and the male will fertilize them. The female will lay between 400 – 750 eggs at a time. Neither parent will provide any care for their offspring. The eggs hatch in 2 to 3 weeks. The tadpoles take 3 months to complete their transformation.

The Pacific Tree Frog was recently split into 3 different species based on DNA, but the analysis wasn’t great and it was merged back together.

The Pacific Tree Frog is the State Frog of Washington

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California Tree Frog (Pseudacris cadaverina)

photo by Chris Brown / USGS

Common Name: California Tree Frog or California Chorus Frog
Scientific Name: Pseudacris cadaverina or Hyliola cadaverina
Family: Hylidae – Tree Frog family
Locations: Mexico and the United States (California)
Male Size: 1.4 inches (36 mm)
Female Size: 1.8 inches (45 mm)

The California Tree Frog can be called the California Chorus Frog due to them being placed in the Chorus Frog genus – Pseudacris. Researchers have proposed moving the frog into the genus Hyliola along with the Pacific Chorus Frog. They are more similar to other Chorus Frogs, in that they aren’t found high in the trees. These frogs like to live in crevices or cavities in boulders along streams. The frogs blend into these boulders with their rough skin and gray / brown color.

Breeding takes place in the streams from February to October. Reproduction for the California Tree Frog is pretty standard. Males will call from the streams to attract potential mates. Once the female selects the mate, the male will grasp her from behind in amplexus. The female then lay her eggs and the male then fertilizes them. Neither parent provide any care for their offspring. The larval period for the tadpoles ranges from 40 – 75 days.

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Sonoran Green Toad (Anaxyrus retiformis)

photo by William Flaxington

Common Name: Sonoran Green Toad, Pima Green Toad
Scientific Name: Anaxyrus retiformis
Family: Bufonidae – True Toad Family
Locations: Mexico and the United States
US Locations: Arizona
Size: 1.5 – 2 inches (40 – 49 mm)

The Sonoran Green Toad is known for their yellow / green spots on the dark black background. The toad has lived over 15 years in captivity, which is relatively long for a toad. They are a highly fossorial frog, spending most of their days underground.

Once the summer rains come, the male Sonoran Green Toad comes to temporary filled pools to breed. The males will start to call from grass surrounding the pools to attract females. They are known as explosive breeders due to them only mating for a few days compared to weeks like other frogs. The females will carry the male from the grasses to the water where the females will lay her eggs and the male will fertilize them. The two toads will then part ways and provide no care for the offspring. Females will lay between 5 to 200 eggs. The eggs will hatch into tadpoles in 2 – 3 days. Then, the tadpoles take 2 to 3 weeks to complete their metamorphosis.