Reptile & Amphibian Forums

I almost never post on the kingsnake.com boards but I always seem to find arguements about whether one frog, turtle, or lizard is or is not a species. I decided to chime in from an actual biologist's perspective. Probably the best concept of what a species is or is not is the evolutionary species concept. This essentially said that any group of organisms isolated from other such organisms and on a single trajectory are their own species. What this actually means is there is an astronomical number of species. If you have bullfrogs in Ohio that will never ever mate will bullfrogs from Kentucky, they may be two seperate species. What this means to us as hobbyists is that if a herp is from a different area and they look different or at least would not mate with herps from another area, they are a seperate species. So a lot of "color morphs" or interbreeding species may actually be seperate species. I hope that helps to educate some people on the scientific basis of what a species is. I just get frustrated with all the debate! And yes, I am a real biologist with degrees and all.

When you say "would not mate with herps from another area" do you mean that literally or do you mean could not mate or would not ever get the chance?

Well when I say they aren't mating, I mean they are seperated somehow. This may be a seperation by distance, physical restraints, time of mating, or any other seperation. Like in my example, bullfrogs from one area may never ever mate with other bullfrogs because of distance. But then you also have organisms that can't mate with each other even if they wanted to. In insects the genetalia often is built like a key so only certain males can actually mate with certain other females. Then, of course you have amphibians that mate at a certain time of year or time of day.

Thank you for joining us with this information. It's very interesting. Would that make our various Dendrobatid color morphs of what is considered a single species now by this same definition, all different species? Color morphs are essentially a certain population with a particular color pattern from a defined area that is separated from other areas where others of the tinctorius frogs are identical in all physical aspects except for color. In this case, Dendrobates tinctorius would turn into many different species. D. pumilio bastimentos from an island would be a different species entirely from D. pumilio "blue jeans," from a different area, even though they are distinctly very much alike in habits, anatomy and physiology. These are just examples, of which there are a multitude.

There are some taxonomists who would prefer to group what we usually consider as a distinct species, Dendrobates azureus, with Dendrobates tinctorius. There have always been "groupers" and "splitters" among the biology taxonomists. I imagine as more DNA comparisons become more available, we'll have a whole new set of rules.

Your views are so welcome to us, in particular, because we are interested in keeping the original lines of even color morphs as pure as possible without even cross breeding color morphs, and creating "designer frogs" is frowned upon as being unethical, although there is no set dogma rules as yet, just a set of ethics that almost every dart breeder follows.
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Patty
Pahsimeroi, Idaho

D. auratus blue
D. galactonotus pumpkin orange splash back
D. imitator
D. leucomelas
D. pumilio Bastimentos
D. fantasticus
P. terribilis mint and organe
D. reticulatus
D. castaneoticus
D. azureus
P vittatus
P. lugubris

The evolutionary species concept is valid in some instances, and not in others. In reality, I would say that the best definition of a species is a combination of the various species concepts that are out there.

Your example of the bullfrog is sorta right. The issue, though, is that the population is continuous completely through those areas. While Kentucky frogs may not breed with Ohio frogs, there is a connection between the populations (bullfrogs were a bad example though since they're so prolific, lol).

Personally, I would say that the evolutionary species concept applies to some of the Dendrobatid species. I'm going to be researching D. pumilio for my masters, and I personally think that in Bocas del Toro at least, the evolutionary species concept could be applied to those populations there, at least in part. The populations on those islands are not going to be in contact with one another for thousands of years, so they're going to be on their own evolutionary paths. They're just starting to speciate, IMO. When I traveled there, I noticed behavioral and morphological differences between the various color morphs (there is also toxicity differences), so I would say that if they aren't considered separate species (and they probably shouldn't at this point), I at least think that they should be subspecies.

There is inherent error in any of the species concepts. For instance, the biological species concept is not foolproof. Different species are able to breed with one another and are still considered "species."

Like I said, the best definition is probably a combination of all of the species concepts.

Well, I would argue that the evolutionary species concept is always valid and is the only valid species concept. My bullfrog example may have not been the best example. A much better example would be the multiple disjunct populations of hybrid Hyla frogs across the eastern US. Each of these populations could be considered a seperate species as they are truly distinct populations not breeding with other hybrid Hyla populations.

Of course I do not take the evolutionary species concept to the extreme, which is that each and every self-contained population or each and every single celled organism is its own species. That would be extreme to say that my population of Blaberus discoidales is different from someone elses populations and that my population is Blaberus kurtiales or whatever. A bit insane.

As an entomologist I have throw the biological species concept out the door years ago. That only applies to sexual organisms, really. In my field many of the organisms are asexual or at least have asexual phases and populations so then you cannot even begin to apply that species concept... let alone on bacteria or something similar.

It is also my belief that we really need a new system of species classification. Many far superior scientists have suggested them. Are currently heirarchy and binomial system leads to some very interesting issues. Some of them are valid and some are silly. I won't even get into those, though.

To MonarchzMan1: Have you just started your MS? If you end up doing lab work, you are much smarter than me. I'm always stuck out in the field.

To Slaytonp: Just a note on your mentioning of designer frogs. I actually come from the school of thought that once an organism is out of its natural habitat and is being bred soley as a pet or for personal use, it is domestic. In that sense, people are more than welcomed to go wild with breeding colors and strains, as long as they tell you what they are. Plants are a perfect example of crosses and color breeds. I think killifish keepers go nuts about keeping species or variations from different areas seperate but, like I said, these are no longer wild animals. But, that's just my opinion. I just hate to see pet "discrimination" when people think someone is below them because they breed to morphs together to make a color/pattern they want. There are places for seperated and specific bloodlines and places for "domesticated" ones.

That is just my two cents! And for anyone who reads this, I am happy to answer questions about science-y stuff to the best of my ability. Please be warned that my focus is on entomology and northern forest ecology.

Well, the current concepts that we've got right now are probably the best compromise at the moment. It's actually quite difficult to classify species because everywhere you look in nature, there will be exceptions. For any of the concepts. You noted the Biological Species Concept works for sexual organisms which is true (I would also guess that the parthenogenic insects you have have populations in the wild that have males, otherwise they'd be pretty doomed as a species). The evolutionary species concept gets muddled when you get naturally interbreeding species, for instance. I believe there are love birds in Africa that can interbreed with viable offspring, so it begs the question of are those two different species on their own evolutionary path and since it seems as though they're not, what do you consider them then?

Personally, I don't know that there will ever be a "perfect" definition of species because nature loves to throw screwballs into the mix.

I'm going to be starting my MA this fall (going onto PhD and I was told MA was the way to go, at least for the college I'm hoping to get into). I actually think that I'd be doing a lot of field work, which I will enjoy immensely. I'm going to be doing the EEB concentration which means lots of observation.

I planned on getting a PhD when I finish my MS but that may or may not alter. I love science but I hate the "office politics", if you can call it that. I really should do it but I am sick of some of the people I have to deal with. I'm sure you can understand what I mean. Science is about 50% scholarly work, 30% fun, and 20% pompous asses. Haha.

You may have underestimated the percentage of pompous asses. They are a cross-over group that even slide into your fun, especially if you need funding.
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Patty
Pahsimeroi, Idaho

D. auratus blue
D. galactonotus pumpkin orange splash back
D. imitator
D. leucomelas
D. pumilio Bastimentos
D. fantasticus
P. terribilis mint and organe
D. reticulatus
D. castaneoticus
D. azureus
P vittatus
P. lugubris

It is true that dart frogs, once in the trade, are captive species, although I wouldn't call them "pets," as such. In captivity, they some of their original qualities, mostly their toxins. This is due to the different kinds of insects and foods that we must feed them, which apparently lack the precursor chemicals needed for making the toxins. I wonder if over time, captive species will lose their ability to "manufacture" these toxins entirely.

However, the concern with most of the Dart community, many of whom are doing field research in south America, is not simply snottiness about purity, it is a genuine concern that these frogs are rapidly disappearing in the wild, and most of us would like to maintain as much as possible, their original genetics. Most breeders who sell them as captive bred frogs, keep close track of their blood lines and population of origin.

Of course, once someone has them, what they do with them is their own business, as long as they don't misrepresent them if they distribute them to others. Also, one is hardly going to improve upon their already fantastic coloration by deliberately cross-breeding.

The evolutionary history of dart frogs, or perhaps most frogs and other amphibians for that matter, is difficult to trace, because fossils are so rare. No one even has a clear idea of exactly how long they've been around, how and when they branched off, or from what common ancestor they might have originated. I think there was a recent discovery, (controversial, as usual) of an obligate egg feeder in amber dated at about 20,000 years ago, designated as a Pumilio sp. That dating is of course recent in geological time. They were already evolved into the specialization of caring and feeding for tads at that time, and prior to that, it's all guess work.

I won't live long enough to see the current system of classification totally replaced, but I doubt it could possibly disregard evolution entirely.
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Patty
Pahsimeroi, Idaho

D. auratus blue
D. galactonotus pumpkin orange splash back
D. imitator
D. leucomelas
D. pumilio Bastimentos
D. fantasticus
P. terribilis mint and organe
D. reticulatus
D. castaneoticus
D. azureus
P vittatus
P. lugubris

Oh, I understand completely. I haven't ever crossed anything or don't really plan to. Nature has generally done a pretty good job and I don't think I can do much better... at least not with amphibians. Outside of breeding for colors I can't imagine why you'd mess with it... but I have a sore spot because of some people who think that trying to breed a color strain is evil. I'm sure you know what I mean. It is funny though, going full circle, because most of the original animals in captivity were bred for specific colors and traits, irrelevent of their heritage whereas now people want to keep strains from seperate ponds apart.

It all has its merits in my eyes. Preserving the genetic diversity on earth is certainly something of real concern considering how some people treat the earth. When I'm out studying forest floor ecosystems I generally find 50% of the macrofauna to be entirely exotic. And a lot of what I should find just isn't there anymore.

Then again a lot of people keep animals for their enjoyment and asthestics.

And as someone who has dealt with strict research and strictly asthetics, I see the merits in both. Nature's art and man's art are both OK by me, as long as we know when and why to seperate them!