Metamorphosis
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Metamorphosis is a new tool we are working to implement to help show the process of metamorphosis in amphibians. This will allow you to flip through several stages in an amphibian's lifecycle and compare and contrast with other species. Each photo is dated to roughly show the progress through the year. Keep in mind that there is some overlap in most timelines. Some amphibians may be leaving the water before their sibling develop both sets of legs or some may breed earlier in one part of the state than in another. Embryo development times are generally based on temperature, with slightly warmer temps leading to sooner hatch dates. There is also variability amongst all species in color/pattern and this is not designed to capture that aspect. This also heavily focuses on Virginia, and some species may breed at different times in different regions.
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Eastern American Toad (Anaxyrus americanus americanus)
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NotesBreeding: Breeding can occur in rivers, oxbows, lakes, ponds, pools, ditches, or anything of the like. Breeding can start as early af February, and typically lasts through late April. In higher elevations (especially in localized areas that lack Fowler's Toads (A. fowleri)), breeding may occur as late as June.
Eggs: Eggs are laid in curly, ribbon-line strands. Sometimes they will pile-up, but they tend to keep this shape. After 3-12 days, the eggs will hatch. Tadpoles: Tadpoles take about 40-70 days to develop into metamorphs. Tadpoles are mostly black. They typically shoal near the edges of the water bodies they are in. Their brown eyes can be used to separate them from other genera. They have a large snout and a small mouth. Brown color begins appearing just prior to posterior limb development. Once fore limbs are present, adult pattern is nearly complete. |
Metamorphs: Metamorphs are tiny, close to size to one's pinky nail. It is best to ID metamorphs in this genus based on seasonality and location. Remember that this species comes in several colors.
Froglets: By this point, some enlarged warts can be noted on the tibia/calf. These warts will be distinctly larger than the warts on the thigh.
Froglets: By this point, some enlarged warts can be noted on the tibia/calf. These warts will be distinctly larger than the warts on the thigh.
"Gray Treefrog Complex" Gray Treefrog (Dryophytes versicolor) & Cope's Gray Treefrog (Dryophytes chrysoscelis)
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NotesBreeding: Unfortunately these two species are identical in all ways but genetics and vocals, so unless you are outside of the areas where the two overlap, ID for tadpoles will be impossible. Breeding often occurs in ditches, puddles, swimming pools, or anywhere else rainwater may pool up. They begin to breed late April, peaking in June and early July, but will continue through August.
Eggs: Eggs are typically laid in tight, round clusters. Eggs hatch is 3-7 days. Tadpoles: Tadpoles are typically black and gold, slowly becoming more gold with age. They often have a dark smudge from their eye to their mouth. The body is short and round compared to Lithobates or Anaxyrus species, and the snout and nose are down-curved. After legs begin to form, the gold will often turn green to gray. Toe pads can be seen on the feet early into limb development. |
Metamorphs: Metamorphs typically leave the water around day 45-65. Metamorphs are tiny, close to size to one's fingernail. They look like small versions of the adults, but with larger heads respectively. They also have a higher tendency to be green than adults. It is important to note as well that metamorph Squirrel Treefrogs (D. squirrella) can be very similar, including having a pale "tear" under the eye. This tear fades very quickly on Squirrel Treefrogs, and other pattern traits can be used to discern the two where Cope's Gray Treefrogs and Squirrel Treefrogs overlap.
Froglets: Froglets are small versions of the adults.
Froglets: Froglets are small versions of the adults.
Southern Leopard Frog (Lithobates sphenocephalus)
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NotesBreeding: Breeding often occurs in grassy marshes but also swamps, vernal pools, or ditches from February - April. Occasionally this species will call and breed again in September - November. In other states, breeding may occur year round.
Eggs: Eggs are laid in clusters. Eggs hatch relatively quickly (7-14 days). Note the eggs have a thicker gel envelope than that of the Pickerel Frog (L. palustris) but much thinner than that of the Wood Frog (L. sylvaticus). Tadpoles: Tadpoles are similar to treefrog tadpoles when young (note eyes), but then swing toward other tadpoles such as the Green Frog (L. clamitans). The caudal fin is much higher and typically less pointed than that of Green Frogs. |
Metamorphs: Dorsal pattern starts to develop after forelimbs, but before the reasobstion of the tail. This is when ID becomes much easier.
Froglets: Similar to adults but tiny. Can be distinguished from Pickerel Frog by the dorsal and leg pattern.
Froglets: Similar to adults but tiny. Can be distinguished from Pickerel Frog by the dorsal and leg pattern.
Spotted Salamander (Ambystoma maculatum)
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NotesBreeding: Breeding typically occurs from January - March. Males deposit spermatophores, packets of sperm protected by a gel layer, on debris at the bottom of vernal pools. The females then collect these spermatophores (sometimes days later) with their cloaca. After waiting in the pool for a day or two, females deposit their egg masses.
Eggs: Egg masses come in three morphs: opaque, clear, and intermediate. These are determined by the female's genetics. Embryos start to become enveloped in an algae called Oophila amblystomatis, which supplies extra nutrients to the embryo. Spotted Salamanders were the first ever known photosynthetic vertebrate. Eggs take 20-60 days to hatch. Larvae: The larvae are pretty typical ambystomid larvae, and look like small Axolotls. The are often paler than Marbled Salamanders (A. opacum), smaller-headed, less robust, and lack the silver spots down the lower flank. |
Metamorphs: New metamorphs often lack spots, but may have some yellow specks. Spots develop soon after leaving the water.
Juveniles: Juveniles typically appear as small, chubby adults.
Juveniles: Juveniles typically appear as small, chubby adults.
Marbled Salamander (Ambystoma opacum)
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NotesBreeding: Breeding typically occurs underground and is not often seen/documented.
Eggs: Females dig small "bowls" under logs in dry vernal pools in late September-November. They lay their eggs, which are loose, in these depressions and guard them until the heavy, fall rain comes. The eggs draw moisture (and debris) from the soil, and therefore generally look like small, spherical balls of mud. Once the pools begin to fill with water, the female will leave the pools, and the eggs will begin to hatch within hours. Larvae: The larvae are pretty typical ambystomid larvae, and look like small Axolotls. These larvae are relatively short, with large heads. They can often be distinguished by their shape and seasonality alone, but they can also be quickly discerned from Spotted Salamander (A. maculatum) larva by the row of silver flecks at the edge of the venter. |
By around May-June, the Marbled Larvae will leave the vernal pools; well before the Spotted Salamander larvae get large enough to compete with them for food sources. Marbled Larvae develop rows of yellow/green spots down their backs that become more noticeable as the metamorphosize into late-stage larva and metamorphs.
Metamorphs: Metamorphs will retain their yellow/green spots for a few days after leaving the water. They may looked lightly "salted" with more and more silver flecks developing and morphing into bands as each day goes by. Their tails stay keeled for several weeks as well. After about a month, they become that more recognizable black and silver salamander with a cylindrical tail.
Juveniles: Juveniles are similar to the adults, though often boasting bigger heads (proportionally) and shorter tails.
Metamorphs: Metamorphs will retain their yellow/green spots for a few days after leaving the water. They may looked lightly "salted" with more and more silver flecks developing and morphing into bands as each day goes by. Their tails stay keeled for several weeks as well. After about a month, they become that more recognizable black and silver salamander with a cylindrical tail.
Juveniles: Juveniles are similar to the adults, though often boasting bigger heads (proportionally) and shorter tails.
