When you live in the darkness of the abyss, finding a partner is hard and keeping a partner is even harder. Deep-sea anglerfish, one of the iconic ambassador species of the deep ocean, have found a novel solution to this problem–dwarf males are sexual parasites that latch onto the body of the much larger female anglerfish and then physically fuse to their partner, becoming permanently attached to the point where they share a circulatory and digestive system.
Parasitic dwarf males are uncommon, but not unheard of, throughout the animal kingdom. Osedax, the deep sea bone eating worm, also maintains a harem of dwarf males in a specialized chamber in their trunk. But few species, and no other vertebrates, go to quite the extremes of the anglerfish. And with good reason.
Vertebrate immune systems have a long shared history. The Major Histocompatibility Complex (MHC) is a suite of genes shared among all gnathostomes–the taxonomic group that contains all jawed vertebrates, from fish to fishermen. It creates the proteins which provide the foundation for the adaptive immune system, the core complex which allows bodies to tell self from no-self, detect pathogens, and reject non-self invaders. Suppressing the MHC seriously inhibits a vertebrate’s ability to fight off infection.
Incidentally, not all deep-sea anglerfish have parasitic dwarf males, and the species most often presented as a type specimen in the popular press, the humpback anglerfish Melanocetus johnsonii, is one of several that do not have permanently attached parasitic dwarf males. M. johnsonii males are free-swimming throughout their life, they’re just small and clingy.
I’d like you to meet a very dear friend of mine. This is Melanocetus johnsonii, the humpback anglerfish. If you follow the deep sea at all, you’ve probably met this delightful creature. She was featured on the cover of time magazine, barely losing out to Newt Gingrich for 1995 Vertebrate of the Year. Since then, she has been a standard-bearer for the deep sea, an iconic species, immediately recognizable. Stories of her exploits abound, and no story is more compelling that the tale of the hapless male anglerfish, a parasitic dwarf that lives its entire adult life fused to the larger, more capable female angler fish.
There’s just one problem.
Melanocetus johnsonii, along with the four other anglerfish that make up genus Melanocetus, don’t have parasitic males. Males of this genus are still significantly smaller and lack lures, but they retain their free-swimming lifestyle into adulthood, occasionally biting into the side of a much larger female for a temporary coupling, where gametes and food are exchanged. This temporary coupling, in which no tissue fusion takes place, has been observed only three times: once during the filming of the BBC Blue Planet documentary; once off the coast of Japan; and once, confusingly between a male Melanocetus johnsonii and a completely different species, Centrophryne spinulosa. In none of these instances was the connection permanent, and no reduced males have even been found attached to a Melanocetus. Read More
I started my career in marine science working with seahorses, so these goofy, thoroughly un-fish-like fish, hold a special place in my heart. All seahorses are pretty weird, but pygmy seahorses might be the weirdest. These tiny animals, barely 2 centimeters long, live exclusively on gorgonian corals, their lump profile allows them to blend perfectly into the backdrop. Their bulbous protrusions will assume the color of their host coral.
Welcome back to another exciting installment of the incredible biodiversity of this incredible Aquaman cover. Today we’re investigating species 4 through 6, where we’ll meet one of my favorite mid-water fish.
4. Fangtooth (Anoplogaster cornuta)
With the largest tooth-length-to-body ratio of any fish, the fangtooth has earned its menacing name. Unfortunately, this intimidating creature barely reaches 18 centimeters in length, hardly the massive, Batman-swallowing maw illustrated to the right. Fangtooths are among the deepest swimming fish. They can be found as far as 5000 meters down, though they are more common in the midwater (200-2000 meters). Read More
Today marks the end of Geoff Johns’ 25-issue run as lead writer for Aquaman. It is not hyperbole to say that he revitalized the king of Atlantis and helped cast off the stigma of the Superfriends. Aquaman was no longer a one-trick hero floundering about for relevance, trying to find his plaice in the DC Universe. Johns’ Aquaman had depth. The characters were compelling, the stories engaging. And, after more than 2 years, it was clear that this new Aquaman wasn’t just a fluke.
All puns are most definitely intended.
In honor of Johns’ 25 issue run, it’s time to plumb the depths of his ultimate issue and do what I do best: over-analyze a comic book and dredge up as much tenuous symbolism as possible. This is Southern Fried Science and I’m talking about Aquaman, what else would you expect?
The anglerfish symbolize Aquaman’s relationship with Mera
Aquaman and Anglerfish, Aquaman #25, DC Comics
Here we find Aquaman diving deep into the Trench, searching for an army of lost Atlanteans to command. During the course of his dive, we discover that, though Aquaman is fighting to reclaim Atlantis, his one overarching goal is to find his wife, Mera. It is not a coincidence that we see him surrounded by deep-sea anglerfish — Melanocetus johnsoniito be precise. In many ways, the life-history of the anglerfish mimics Aquaman’s relationship to Mera.
Earlier this week, Fox News commentator and all-around terrific guy* Erick Erickson, while discussing a recent Pew Study that revealed that women were the sole breadwinners in 40% of US households that contain children, had this to say:
“I’m so used to liberals telling conservatives that they’re anti-science. But liberals who defend this and say it is not a bad thing are very anti-science. When you look at biology—when you look at the natural world—the roles of a male and a female in society and in other animals, the male typically is the dominant role. The female, it’s not antithesis, or it’s not competing, it’s a complementary role.”
I’m not sure where Erickson got his science education from, but it’s pretty clear he should have spent a little more time shopping around on the free market, because he sure is wrong. How wrong? I managed to assemble this list of 10 marine species with dwarf, parasitic, or otherwise reduced males (including an entire female-only class) while waiting for my toast**. So have a seat and let me show you how much weirder and more wonderful the world is than Erickson’s Disney-esque misinterpretation of biology.
The deep-sea Anglerfish is among the most common examples of parasitic males in the marine world. Anglerfish comprise a variety of taxa in the order Lophiiformes. Almost all (females) possess a specialized appendage that acts as a lure to attract unwary prey. Life in the deep sea is rough–even though it is the largest and most diverse ecosystem on Earth, biomass is fairly low–so finding a mate is a struggle for these slow swimming fishes. The solution: carry your partner with you.
Male anglerfish are tiny, often less than 5% the size of the female, but they possess powerful olfactory receptors, allowing them to seek out females. Once a mate is located, the male anglerfish latches on to her abdomen, fuses his circulatory system with hers, and is then slowly digested until there’s nothing left but a sac of gonads surrounded by basic life-supporting tissues. Female anglerfish are not monogamous, either. At any given time she could be covered by a half-dozen parasitic males. Kinky.
Last time I paid the hapless mariner a visit, many readers interpreted my incisive criticism of the science behind Aquaman as evidence that I had it out for our scale-clad hero. Since you all know that I’m going to take the misguided marine science in this volume to task, let’s start with all of the good stuff in this reimagination of DC’s oft-mocked champion.
The central conceit of New 52 Aquaman is that the comic book world has the same perception of Arthur Curry that we do–a hero with oddly specific and mostly useless powers that talks to fish. In addition, the citizens of the DC Universe believe that Atlantis is a fairy tale, so Aquaman’s kingly status is meaningless to the surface dwellers. The hybrid of a human father and Atlantean mother, Aquaman feels out of place in Atlantis and chooses to return to the surface with his wife, Mera. Comparing himself to his lighthouse-keeper father, he explains that even though he loves the sea, someone must protect the shore.