Did you read the paper? Because the paper doesn't contradict the claims that "Pets != humans".

The argument that the paper made, and I quote "I argue that we should drop the belief in the equal value of human life, replacing it with a graduated view that applies to animals as well as to humans.", emphasize the first half of the sentence (sidenote: the claim shouldn't be a surprise to anyone that know about Singer's utilitarian stance, he's super consistent in being an utilitarian :-) ). He isn't saying that pets is equal to human in moral status, he's saying that the difference shouldn't be explained just by species.