A new breed of romance novel is introducing readers to a unique spin on the dark and mysterious stranger. He’s got sharp teeth, a tail and dominated the earth tens of millions of years ago, just as he’s sure to dominate your … heart? Welcome to the world of dinosaur erotica.

Two 20-something women that go by the pen names Christie Sims and Alara Branwen have found success with short erotic stories about women who find comfort in the claws of dinosaurs and other beasts. The “dynamic duo of monster porn” recently told New York Magazine’s “The Cut” that Amazon sales have been lucrative enough to outstrip the earnings of their engineer and accountant friends.

But what do dinosaur researchers think of stories like “Running from the Raptor” or “Taken By The Pterodactyl”? (Note that pterodactyls are winged lizards, not dinosaurs.)

“Never would have believed it if I hadn’t seen it,” John Cisne, a Cornell paleontologist, wrote in an email. “But why not ‘Ptaken by a Pterosaur’ with the extra ‘P’? Or ‘Ptaken by Pteranodon Juan’?”

Sims and Branwen do make some occasional stabs at paleontological accuracy: the amorous dinosaur in “Taken by the T-Rex” is described as “partially covered in green plumage, [with] filament-like feathers coating its underbelly and flanks.”

But the inclusion of feathers notwithstanding, this dinosaur erotica suffers from a larger anatomical issue: genitalia. Since soft tissues do not survive fossilization, scientists can’t be exactly sure what kind of equipment dinosaurs were packing in their nether regions.

Some scientists speculate that T. Rex and his cousins sported cloaca -- the all-purpose orifice used by most modern birds, amphibians and reptiles for urination, defecation and copulation.

“If dinosaurs also had cloaca, according to theory penetration would have occurred when the male cloaca ... bulged out into the cloaca of the female -- much like a couple of plumber’s plungers pushing against each other,” Australian science writer Carmelo Amalfi wrote for Cosmos in 2006.

“A couple of plungers pushing against each other” is not a phrase to make bosoms heave. And if you investigate sex by cloaca even further, the results are even more disheartening. The “cloacal kiss” performed by modern birds can last as little as only a few seconds -- not exactly thrilling by mammalian standards. (Crocodile copulation, at least, seems a little more intimate, as you can see in this video.)

“Then there’s the matter of male birds typically jumping on females’ backs and trodding [on] her sides to get her to evert her tail to expose the cloaca (bird mating takes a lot of cooperation),” Cisne says. “I can’t imagine the jumping part for tyrannosaurs, much less sauropods, without disastrous consequences for milady, human or otherwise.”

On the other hand, male dinosaurs could have had penises -- though they would probably be radically different from the organs seen in mainstream erotica. There are a few avian species like ducks and ostriches that possess something passing for a penis. In this case, the penis is an extension of the cloaca that fills up with lymph, not blood.

“Even though they have cloaca, more primitive birds have penises (albeit small but effective),” writes Mark Norell, the chairman and curator of the division of paleontology at the American Museum of Natural History. “Crocodiles have larger ones, and since the non-avian dinosaurs are descended from the same common ancestor as birds and crocodiles we would expect that they would have them also.”

Norell noted that one of Sims’ books, “The Balaur’s Delight,” stars a dinosaur that he himself described, along with three other scientists, in the Proceedings of the National Academy of Sciences in 2010.

“Unfortunately I get no royalties,” he wrote.

Most people will probably not be looking to “Ravished by the Triceratops” for detailed treatments of realistic dinosaur mating. But, Cisne says, any kind of art can raise important questions about the line between reality and artifice.

“I still can’t believe it -- dinosaur bodice-rippers,” Cisne says. “Is that what Tyrannosaurus’ little front legs were really meant for?”