No, that's just a population with different traits, not a new species.
The dogs are not different "species" any more than us pink-skinned humans are a different species than black/red/yellow/brown-skinned humans.
Even if they look pretty different in shape and size and colour.
What makes a new species is losing the ability to breed true with your ancestor's species and have fertile offspring.
Actually, it is neither. Strictly speaking a new species is defined as a distinct lineage which is separate from other closely related lineages. This can be because they are infertile, because they breed at different times or places, or because one ends up isolated on an island and genetically diverges. Think of it like this. The physical ability to interbreed(eg your gametes can successfully combine) is constrained by a relatively small number of genes. If those genes are under no selection to diverge from eachother, or if they are conserved due to specific pressures keeping them in place the rest of the genome is free to evolve, but unless it gets REALLY distant, they can still breed successfully.
This is really really common among reptiles and amphibians. Toad species which have been distinct lineages for millions of years can still interbreed. Species of python, distinct from eachother since the supercontinent of Gondwana split up, can still interbreed. I know. I have seen hybrids between african pythons, and australian pythons. I have also seen hybrid toads, and hybrid turtles. Not at all difficult. It is not at all difficult to do.
Sure that both strategies are viable, my friend. But there is a trade-off. I've read papers that claim the species brain size is proportional to the amount of maternal care. That means they are smarter.
That is not a real trade off. That is just auto-correlation, there is no functional link between the two. Octopus have hundreds of thousands of offspring, but once they hatch, mom dies. Octopus are amazingly intelligent. Turtles, once you correct for their lack of speed, are better problem solvers than mice, and monitor lizards can count, which is something most birds cant do.
The only reason there is a correlation is because of a few very odd lineages of intelligent social mammal, and birds who have been doing the parental care thing since before they were birds, and evolved from intelligent predators.
Now, you can make a case for social intelligence requiring parental care. However even that does not really hold water, because an organism COULD spawn en masse and then meet up into social groups later. There is nothing at all stopping that from happening.
Like the horse and the donkey. Common ancestor, but their offspring is not fertile (the mule). So they are two different races even if they are much more similar to each other than a cihuahua is to a newfoundland (both dogs, both can interbreed with some assistence and have fertile although somewhat weird offspring).