Fuliginous Frogs and Baffling Batrachians

Fuliginous means sooty, and is being used in the sense of obscure, as in seeing through a glass, darkly. In my case it certainly applies to Mink Frogs (Lithobates septentrionalis), since for the last more than half a century of my life I've been unaware that these small amphibians even existed. They also share the same habitat as the Bullfrog (Lithobates catesbeianus) and the Green Frog (Lithobates clamitans), all are similarly colored and can be confused with one another.

One thing that's easy to determine in all three species is the frog's sex: the male's tympanum or eardrum is significantly larger than the eye, in the female it's smaller. Useful information if one intends to kiss a frog and wants to know in advance if the result will be a handsome prince or a beautiful princess.

The key distinguishing feature of the Bullfrog is that it lacks dorsolateral ridges, the folds of skin that start behind the frog's eyes and run down its back. Of course, if the Bullfrog in question is fully grown there's no possibility of confusion, at over 15 cm in length it's much larger and more robust than its cousins.

So, looking at the Bullfrog: this is a female ...

... another a female ...

... and this frog with the large tympanum is a male.

Note the dorsolateral ridges along the backs of these of Green Frogs (for anyone interested, a grouping of frogs is called an "army" of frogs). "Green" is a bit of a misnomer, the color in all three species can vary from grungy brown, as in the individuals below, to green, with or without darker spots.

This male Green Frog is about 10 cm long, fully mature and sporting his breeding colors. Note the bright yellow throat – male Bullfrogs and Mink Frogs throats will also turn this color when they are ready to mate. A more important distinguishing characteristic of Green Frogs are the markings on their back legs: they are distinctly barred, with the stripes running transverse to the length of the legs.

A female Green Frog ... note the smaller tympanum.

Although this female was much smaller Mink Frogs can grow to a length of almost 8 cm. Like the Green Frog they have dorsolateral ridges, but Mink Frogs tend to be mottled, and their back legs have spots rather than transverse stripes. Males and often females also tend to show a tinge of yellow on their throats. However, none of these characteristics can reliably separate Green and Mink frogs in the field.

As a rule it's preferable to photograph wild things in a natural setting, but Mink Frogs do have one unique feature that sets them apart from their relatives and that's why this frog was captured. This is one froggie you definitely don't want to kiss because Mink Frogs come by their name honestly, and, as advertised, this little frog smelled exactly like rotting onions.

"No Name" Nature

This large caterpillar was found crawling in the vegetation near the forest floor. Given its size, about the length and width of my pinky finger, and knowing that Luna Moths pupate in the forest litter, often incorporating dead leaves in their cocoons, it seemed reasonable to conclude this was the larval stage of Actias luna.

My first attempts at check my supposition drew a blank – there was nothing in either my field guides or the Internet that resembled this caterpillar. It took a bit more digging to find out that my first surmise was correct after all. This is a Luna Moth caterpillar, but larvae that will overwinter often take on an amber coloration.

It's interesting to note that when danger is imminent this caterpillar instinctively hides its head in the same manner as the Promethea Moth larva. Meanwhile the large terminal pair of pseudopods are raised in the air, their colors also strongly hinting that the tail end is the insect's the head.

A bit of thought, research and luck solved the caterpillar conundrum, but sometimes there just isn't enough information in a photograph to even hazard a guess. By far the largest number of files on my hard drive named unidentified are images of fungi. The mushrooms in the next two photos are ubiquitous at this time of year, and many have even left ochre spore prints. But I still haven't figured out what they are.

Gymnopilus sapineus or Gymnopilus penetrans are likely possibilities, although the species accounts are confusing. Could these mushrooms be Cortinarius? There are hundreds of species, difficult even for experts to sort out.

Amanita bisporigera, or Amanita virosa? The difference between the two species is in their spores, something we can't tell from a photo.

Is this a Mink Frog (Rana septentrionalis), or a Green Frog (Rana clamitans)? The two species are easily confused with one another, and there isn't enough evidence in these two views to be a hundred percent sure either way. A photo doesn't tell the whole story, in hindsight it seems that the best move would have been to capture the frog and give it a sniff. Mink Frogs are so called for a reason – they smell like rotting onions.

And assuming this is a Mink Frog it seems that the name Rana septentrionalis isn't correct in any event. Phylogenetic relationships can change in the light of new studies; the Mink Frog and its close relatives are now members of the subgenus Lithobates.

Another dark salamander with blue spots was encountered about one kilometer southeast of Actinolite on a trail managed by Quinte Conservation. This specimen has a darker aspect than the two seen at the Frink Center, and the blue spots are confined mostly to its sides. Could this be a Jefferson Salamander? Or a polyploid hybrid? I think this is probably a Blue-spotted Salamander, but without looking at a sample of its chromosomes under a microscope I'll never really know for certain ...

The pattern of a spider's eyes determines its family relationship, and a photo of this spider's face would go a long way toward making a positive I.D. But as often happens in the world of nature photography the subject didn't want to co-operate. Based on general appearance and color the closest match I can find on the Internet is Pisaurina brevipes. But the pattern isn't quite right and I'm not even sure this a Nursery Web Spider ... maybe it's a Fishing Spider, genus Dolomedes.

Immature jumping spiders can look very different from adults, and even the adults can vary considerably in color and pattern. The jumping spider in the next photo was a hefty specimen, a good 15 mm long, and it's safe to say it's an adult female. My best guess is Phidippus clarus.

The Tadpoles are turning into Tiny Toads

Less than a quarter of an inch long and easily mistaken for an insect or spider, there are hundreds of these little guys currently scampering about on the lakeshore.

To give an idea of scale here's the toadlet sitting in the palm my hand; it's small enough to easily fit on the nail of my pinky finger.

Other tadpoles are turning into tiny Spring Peepers. There is no way to judge size in this image, but this little froglet, encountered in the vegetation bordering the Eastern Ontario Trail, was the same size as the toad above and could fit on my pinky nail with room to spare.

Might as well put these photos of a Green Frog (Rana clamitans) here. This guy is an adult about three inches long, and is sporting his best colors, hoping to attract a girl friend. The dorsolateral ridges (the seams starting behind the eyes and running down the frog's back) set this species apart from the bullfrog.

These Gray Treefrogs (Hyla versicolor) were photographed near the culvert running under the Eastern Ontario Trail just a few feet from where I encountered the Spring Peeper. Gray Treefrogs can vary their color to match the background, and these two were doing a pretty good job of blending in with the leaves of the Virginia Creeper they're sitting on.

A "thumbnail sketch" of the frog on the left ...

... and the frog on the right.

A Gray Treefrog of a dramatically different color. This adult was happily camped out in the reservoir under a potted tomato plant on a second floor balcony. Fully grown frogs are about 5 cm long, twice the size of the little guys depicted above.