Costa Rican Ranids

[pez]

Here is the second post of the "costa rican anuran series". Sorry for taking so much time to post the second one, but I have been on exams and also very very busy with projects. I chose this family of frogs because it is relatively smaller than other families (Bigger ones such as glass frogs, tree frogs and the pristimantis group will come when I have more time.)

There are five species of ranids in Costa Rica: Lithobates forreri, L. taylori, L. vaillanti, L. vibicaria, and my personal favorite L. warszewitschii (it was hard to memorize this name).
All costa rican ranids are identified because of their smooth skin and dorsolateral folds. Many of this species reproduce during all the year and their tadpoles can be found in either ponds, small rain temporal pools and slow moving streams.

Note: I only have "good quality" photos of the L. warszewitzchii, so most, if not all, of the other photos don't belong to me.





Lithobates taylori

Specimens of this frog reach sizes between 60-85 mm. L. taylori has a pointed head with a distinctive large timpanum. The dorsum colors vary between bronze, green and tan. There are present dark elongated spots with a light outline and a pair of dorsolateral folds. It has an extensive webiing between the toeas but lacks webbing in the fingers, just as every other Costa Rican ranid. species lives close to rivers and permanent/temporal pools and can be fond singing near them at night. L. taylori reproducs during the rainy season and it lays egg clutches in ponds or slow flowing streams. Tadpoles feed on algae.
This frog can be fond from Nicaragua to Costa Rican atlantic lowlands and central highlands.





Lithobates forreri
Adult frogs can reach sizes between 60-110 mm. Its dorsum can vary from green to tan and also has dorsal spots. It looks very similar to Lithobates taylori in appeareance but it lives in a different zone, has a different call and is bigger. L. forreri is a nocturnal species found in marshes, ponds, and slow flowing streams. This species in found in the pacific versant and it is present in Mexico, Nicaragua and Costa Rica. In Costa Rica it can be found between 0-850 meters of elevation.



Lithobates vibicaria
This frog measures between 60-90 mm. Its particular characteristics include a green iris and bright red thighs. The dorsal coloration can vary from a bright green in juveniles to a brown or red in adults and has a dark facial mask and a light colored upper lip. Sadly this species is critically endengared and it is only dound in Costa Rican highlands normally above 1650 meters and there is an isolated population in Panama. This frog, together with L. warszewitschii has no vocal sacs or slits but it is still able to vocalize producing a series of short thrills.



Lithobates vaillanti
Adults of this species may reach 110 mm. As all other Costa Rican ranids, this frog has fully webbed toes and two dorsal ridges. L. vaillanti present a wide variety of colors, frogs may be either brown, green, brown with green spots and my favorite, brown with a bright green head. This ranids are active during the night but may be occasionally found during the day. This species inhabits near ponds or slow moving streams and when disturbed, they jump into the water and hide in the bottom. I have observed in different individuals, that they have an specific spot in the bottom of the water, and each time they are disturbed they swim to that specific place, I have also observed this behaviour in L. warszewitschii. L. vaillanti lives from southern Mexico to northern Colombia and in Costa Rica thay are found in altitudes betwenn 1 and 700 meters.


Lithobates warszewitschii
My personal favorite, males reach a maximum length of 43 mm. while females reach 63 mm. This frog differs from other ranids because it has a pointed, arrow-like snout. Red coloration in the webbing and groin and also betwenn 2 and 4 bright yellow stripes, that alternate with black stripes, in the thigh. its sides are ussually gray or black, while the dorsal part has a bronze coloration with small green spots scattered around. L. warszewitschii also has a big eardrum and a white stripe in the upper lip. It can be found from northeastern Honduras to central Panama and in Costa Rica they are found in both versants, Pacific and Atlantic in elevations between 1-1700 meters. This is the less acquatic frog among all other Costa Rican ranids and spends much more time jumping in the forest floor than near streams and ponds, but thay do not go very far from water bodies. It can be either found during the day or during the night. This frog reproduces year-round and its tadpoles are some of Costa Rica's biggest tadpoles and can reach 115 mm.






Bibliography:
AmphibiaWeb - Rana forreri
AmphibiaWeb - Rana taylori
AmphibiaWeb - Rana vaillanti
AmphibiaWeb - Rana warszewitschii
Especies de Costa Rica. Lista de páginas disponibles
AmphibiaWeb - Rana warszewitschii
Savage, J.M. 2002. The Amphibians and Reptiles of Costa Rica. The University of Chicago Press.
Universidad de Costa Rica. s.f.. CATALOGO DE HERPETOLOGIA. Museo de Zoología, Escuela de Biología, Universidad de Costa Rica. s.d.
Leenders, Twan. 2001. A Guide To Amphibians and Reptiles of Costa Rica. Zona Tropical.

[dendromad]

Nice post and pics! I had the pleasure of keeping and raising the only R. vibicaria in captivity outside of Costa Rica when I was working at the Manchester Museum (they have now been moved to Chester Zoo), they are a very beautiful frog. We originally recieved some juveniles and some egg masses.

[pez]

Thanks for sharing your experience. It should be very nice to raise this frogs from tadpoles, specially knowing that they are endangered!

[dendromad]

Found some more pics including one of a R. vibicaria tadpole!

[pez]

Beautiful frogs, thanks for sharing.

[Kurt]

Normally Ranids don't do a thing for me, but Lithobates vibicaria is drop dead gorgeous. Thanks for sharing.