Pinewood Tree Frogs

Hyla fermoralis

One of nine species of tree frogs indigenous to Florida (Bartlett and Bartlett)

Classification

              Kingdom: Animalia
              Phylum: Chordata
              Subphylum: Vertebata
              Class: Amphibia
              Order: Anura (tailless)
              Family: Hylidae (16 species) 
              Genus: Hyla
              Species: femoralisa

Characteristic

Size: Typically these frogs are slender and range from 1 to 1.5 inches long (Johnson). However the female can be a little larger up to 1.75 inches (Bartlett and Bartlett)

Color: Varies from reddish to gray and even green they tend to have chameleon like color changes to blend in with their background (Bartlett and Bartlett) When found on barks of trees they have a dark chocolate appearance with darker blotches that enhance the camouflage effect (Carmicheal and Williams). At rest on a leaf the tree frog appears green with a golden hue that displays the dark bands decorating their skin (Carmicheal and Williams). They can be found blending in to the trunks of trees in the everglades.

Markings: The distinctive patterns of the Pinewood tree frog include a dark lateral line on both the sides that begins in the nostril area thru the eyes curving down to tympanum all the way to the posterior(Bartlett and Bartlett). (Field Guide) The best way to distinguish this tree frog from others is to note the small yellowish spots located on the underside of the inner thigh (Bartlett and Bartlett).

Physical Features: The toes of the Pinewood tree frog are very arboreal without webbing that allows the frog to climb trees (Paulson). Resting this tree frog is generally found on vegetation near the ground however with its’ specialized toes can climb up to thirty feet within trees (Cowley)

         The tympanum or the ear of a pinewood tree frog is an exposed large circle behind the eye (Bartlett and Bartlett). With the inner ear highly developed from its’ ancestors this species can hear the calls of their mates from relatively far distances (Carmicheal and Williams). 
         A big difference between the males and females of the pinewood frog is that males have a dark throat with rounded subgular vocal sacs that are not present in the females (Bartlett and Bartlett).
        Although all frogs do not have the ability to turn their heads they have highly developed peripheral vision (Cowley). The design of the modern amphibian head is highly developed from the ancient ancestor the labyrinthodont amphibian (Barghusen and Hopson).

Distinctive Call: Sometimes described as Morse code series of dots and dashes similar to SOS (Johnson) <USGS frog call look up > The faster moving sounds of dots and dashes are the call for a mate, while a slower sounding call heard on treetops is said to be the call for rain (Bartlett and Bartlett) Tree frogs similar to other toads and frogs hold their nostrils and mouth closed and shunted air moves rapidly between lungs and vocals sacs (Carmicheal and Williams). This sac is an inflatable membrane just below the throat and acts as a resonating chamber to amplify their unique sounds (Carmicheal and Williams).

Chemical Transport: The inefficiency of amphibians’ lungs requires the exchange of gases through their moist skin (Carmicheal and Williams). More gas exchange between air and the blood stream also takes place in the mouth lining and through their smooth lungs (Brow). This helps recycle air and it is easier than taking breathes (Carmicheal and Williams). A “forced pump” extremely similar to lungfish suggest, “that in the change from aquatic to aerial respiration the machinery was already available” only a few changes in the adaptation process allowed amphibians access to terrestrial life (Lawson).

                  The pump works in four steps: 
                        1. The throat moves down and draws in air through nostrils. 
                        2. Nostrils close, as the throat moves up and force air
                           into the lungs
                        3. The throat again moves down and air moves out of lungs. 
                        4. Finally the nostrils open up the throat move up and the air
                           forced out of lung (Brow)

Ecology and Life History

Fitness: Ranked by the IUCN Red List Category the Pinewoods tree frog is a species of “LC” or least concern (Frost, IUCN - Conservation International, and NatureServe). They are considered stable or “within the =/- 10% fluctuation in population range” (Frost, IUCN - Conservation International, and NatureServe).

Reproduction: The process begins with the male mounting the back of the female as she lays her eggs and he pours his sperm over them for fertilization and are secured in a pond or ditch (Wallace). Batches range from 20 to 100 gelatinous covered eggs (Bartlett and Bartlett). Laid during heavy rains in spring and summer in takes the egg, seven to ten weeks in larvae stage to develop into its' adult form (Carmicheal and Williams).

Hybridization: Occurs naturally with Pine Barren and Gray tree frogs but mating calls become very difficult to distinguish between their voices, or becomes intermediate (Bartlett and Bartlett).

Metamorphism: During the seven to ten week period that the eggs change into tadpoles they do not have eyelids, use gills to breathe, posses tails and utilize scraping parts in their mouth for their herbivorous diets(Bartlett and Bartlett) For the most part they eat organic debris, some algae and plant tissue(Frost, Amphibian species of the world. A taxonomic and geographical reference). As the tadpole becomes an adult he must first develop organs such as lungs, a respiratory system, tougher skin, and eyelids, to keep maintain moisture and protect themselves for dry life on land (Paulson). His diet also begins to adapt to life on land. As this tree frog matures into an adult they prefer a more Invertivore diets, or they eat smaller invertebrates found in trees or on the ground (Frost, Amphibian species of the world. A taxonomic and geographical reference).

Phenology: The pinewood tree frog hibernates during the cool dry months of winter and leads a nocturnal lifestyle (Frost, Amphibian species of the world. A taxonomic and geographical reference). They are most active during the spring thru fall season and at night possibly to protect themselves for the warm tropical sun (Frost, Amphibian species of the world. A taxonomic and geographical reference)

Habitats

Description - In Kentucky they can be found in pine wood trees, within cypress tree environments, and often in roadside ditches. Although this species is often found in vegetation low to the ground it can also be located up to 30 feet high in the trees listed above. This particular frog loves to hide under or in rotting logs, stumps during the colder dryer season

Florida’s damp upland hardwoods with an over story of oaks or magnolias and understory of American Holly and hophornbean are a perfect home for this amphibian (Bartlett and Bartlett). As well as the damp upland pinewoods which has the bionetwork of an over story with long leaf pines and understory of shrubby thick sometime grasses herbaceous growth (Bartlett and Bartlett). Each biosphere would also include a system of water within it for the tree frogs’ reproductive behavior. An ephemeral pond often poorly drained low laying and usually man made that fills during rainy season as well as drains during drought is a great place to lay their fertilized eggs (Bartlett and Bartlett). Or the more permanent ponds, containing some amounts of water year round even though the levels fluctuate with rainfall totals, will also allow the eggs to mature from tadpole to frog rather safely (Bartlett and Bartlett). These types of ponds are surrounded by shrubs lining the rim as other submerged vegetation grows under their shadows (Bartlett and Bartlett). The large trees allow the tree frog to climb upward to call for rain or possible predation avoidance. While the wet parts of these damp grounds create a good place for larvae development into swimming tadpoles and eventually tree climbing frogs.

Distribution: 80,000 to 1,000,000 square miles of the Atlantic and Gulf coastal plains including Virginia and Louisiana reported to be common or abundant in Florida (Frost, IUCN - Conservation International, and NatureServe).

Even though the actual number of adult population is unknown it may well exceed 100,000 with the global trend to be stable to slightly declining (Frost, IUCN - Conservation International, and NatureServe).

The migration habits are normally local and commonly between breeding pools close to their terrestrial habitats (Frost, IUCN - Conservation International, and NatureServe). The exact distance this frog will migrate for breeding is unknown but it could be much further between ponds if civilization were not as disruptive with parking lots and land barriers. Barriers prohibiting longer migrations include major highways and other urban development deterrents (Frost, IUCN - Conservation International, and NatureServe).

Note about Species Discoveries

Molecular genetics and intensified exploration especially in tropical areas has led to a significant increase in the numbers of identifiable species in amphibians (Kohler, Vieites and Bonett). At this point species identification has grown from 4533 in 1992 to 5723 by 2003, an increase of 26.3% in 11 years (Kohler, Vieites and Bonett). Even with new discoveries the truth is amphibian populations decline at 32.5 percent rate annually and are globally threatened (Kohler, Vieites and Bonett). This rate is more rapid than birds or any other mammal to date (Michelle S. Koo). Some experts name global warming and dry climates to the decrease in frog populations, while others suggest non-native species invasions or even a simple disease infecting these organisms (Michelle S. Koo). Nevertheless the affects of losing natures amphibians and bug catchers remains to be seen.

Bibliography

Barghusen, Herbert R. and James A. Hopson. "The Endoskeleton: The Comparative Anatomy of the Skull and the Visceral Skeleton." Wake, Marvalee H. Hyman's Comparative Vertebrate Anatomy. Chicago: The University of Chicago Press, 1979. 265-325.

Bartlett, R. D. and Patricia P Bartlett. A Field Guide to Florida's Reptiles and Amphibians. Houston, TX: Gulf Publishing Company, 1999.

Brow, Terry. Wildcat Science. 9 3 2009 <http://www.tvdsb.on.ca/Westmin/science/snc2g1/frogresp.htm>.

Carmicheal, Peter and Winsten Williams. Florida's Fabulous Repitels and Amphibians: Their Stories. Tampa, FL: World Publications, 1999.

Cowley, Marianne. NSIS. 2005. 16 3 2009 <http://www.nsis.org/wildlife/amph/index.html>. Frost, D. R. Amphibian species of the world. A taxonomic and geographical reference. 1985. 20 Feburaury 2009 <http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Hyla+femoralis>.

IUCN - Conservation International, and NatureServe. 2004. 15 3 2009 <http://www.natureserve.org/explorer/servlet/NatureServe?sourceTemplate=tabular_report.wmt&loadTemplate=species_RptComprehensive.wmt&selectedReport=RptComprehensive.wmt&summaryView=tabular_report.wmt&elKey=106454&paging=home&save=true&startIndex=1&nextStar>.

Hammerson, Geoffrey. Hyla femoralis. 2004. 15 4 2009 <www.iucnredlist.org>.

Johnson, Dr. Steve A. Gulf Coast Research and Education Center Plant City Campur. 2007. 20 February 2009 <http://ufwildlife.ifas.ufl.edu/frogs_and_toads.shtml>.

Kohler, John, et al. "New Amphibians and Global Conservation: A Boost in Species Discoveries in a Highly Endangered Vertebrate Group." BioScience (2005): 693-697.

Lawson, Ronald. "The Comparative Anatomy of the Coelom and of the Digestive and Respiratory Systems." Wake, Marvalee H. Hyman's Comparative Vertebrate Anatomy. Chicago: The University of Chicago Press, 1979. 378-445.

Michelle S. Koo, Vance T. Vredenberg, Joyce Gross, Carol L. Spencer, Tate Tunstall, David B. Wake. Visualizing AmphibiaWeb Data with Continuous Cartograms . 2009. 19 2 2009 <http://amphibiaweb.org/amphibian/cartograms/>.

Wallace, Robert A. How They Do It. New York: William Morrow and Company Inc., 1980.