This aberrant polychæte worm has evolved to look like a 16th-century woodcut. Also Evolution has given it the name 'Myzostoma', which just saying would be a good name for a Techno label.
Chaetopterus pugaporcinus the Pigbutt worm has evolved to look like... umm, I dunno. It is identical to the immature pelagic stage of the parchment worm C. variopedatus, except for being 10 times larger; the adult would be a few metres long, but is unknown to science. Yet it finds me in my dreams.
This polychæte worm sucks its head all inside-outy inside its body in the manner of a Robert Crumb cartoon. This allows it to conceal its fangs halfway down its throat, so that they pop out right to the front when it everts its head again upon seeing a tasty 1cm. or 2 cm. line... then it looks like the Chitterer from Hellraiser or Ballerina Girl from Cabin in the Woods or Mr Oral from Nightbreed. Go home evolution, you have been watching too many horror movies.
These polychæte worms are sad. Just look at them. Even the ones that look angry, they are only bottling up the sadness inside. Perhaps some drag-&-drop googly eyes will make them feel better.
They are sad because there is no place for them in Williamson's "Larval transfer" paradigm. That is, there are no other orders or phyla who want to hybridise with them. This in turn is because they are just awful.
Williamson's theory has already featured in a previous installment of the Riddled World of Knoledge (builds up week by week into a comprehensive Is-it-about-a-bicyclopædia of As-any-fule-kno (originally the Riddled World of Gnoledge, but that was before the lawsuit from the Gnole Anti-Defamation League)). Larval Transfer is no longer cool with the hipsters after it went mainstream in the Annals of Improbable Research.* It is mad enough, however, to deserve a return visit.
The idea is that the larval stages of metamorphing invertebrate species are so unlike their adult forms -- grub and beetle, for instance -- that their relationship could never have evolved by natural selection, having no survival value, which is why butterflies and beetles and flies are so rare. So instead these animals must be sequential chimeræ, inheriting two separate genomes from the different sides of their ancestry, one genome shaping the larval form and the second one taking over at adulthood.How did this come about? you ask. Through an unusual, taxon-crossing hybrid mating. Also known as the velvet-worm-fucked-an-earwig explanation for caterpillars and maggots.
Hominid hybridisationWilliamson has elaborate diagrams (not to mention 8×10 color glossy pictures with circles and arrows and a paragraph on the back of each one) showing the gene transfers among echinoderms... between echinoderms and enteropneusts... among crustaceans... but there is no mixed ancestry for polychæte worms! Polychætes grow smoothly from the classic protostome trochophore stage to adulthood by adding segments, without any drastic metamorphosis. Because no other phylum wanted to breed with worms whose idea of a party trick is to evert a face-full of hooks and razor blades.
This resulted in the following śloka, which as you have not heard, I will proceed to relate:
There once was a polychæte worm
Who wanted deuterostome sperm
It wore sexy glasses
when at males it made passes
and primped up its spines in a perm.
To his credit, Williamson did conduct some research into hybrid mating,** attempting to fertilise chordate eggs with concentrated sea-urchin sperm:
----------------------------------------------------------------* Not to mention featuring in New Scientist, to help that journal's credibility battle with National Inquirer.
** Albeit reporting the results in Cell & Developmental Biology, a vanity journal from the OMICs stable that is so notoriously low-rent that they avoid causing the authors unnecessary embarrassment by including either the publisher's name or the journal's within the publication.