All images copyright Alex CF 2014. Please credit and attach a link if used outside this website.
The unfortunate need for humans to realise mythology in flesh has led to many animals being skinned, cut in half and sewn to the back of another equally unsuspecting animal in hope of creating a life form that resembles that which is recorded in the annals of cryptozoology. The most common of which is of course, the Mermaid, often known as the "Fiji Mermaid" - a small monkeys torso attached to the back end of a fish.
The mermaid mythology stems from the Dugong (Manitee), or those afflicted with Sirenomelia. Mermaid effigies adorned the cabinets of many a budding collector during the Renaissance, as did many specimens of dubious origin. Yet the Earth is not without its secrets, and although it is correct that the beautiful Manitee resembles a human with the hind quarters of an aquatic animal, the truth is far more interesting.
Homomimus Aquaticus, or Icthyosapien, is a fish like species akin to Mudskippers (Periophthalmus). Unlike their relatives who would leave the ocean entirely, they maintained a relationship with the sea, growing immensely in size, yet only coming on land for courtship rituals. Their upper torso adopted a standing stance, which is beneficial when keeping alert for predators. The neck developed as a result of this, and males will lie with their tails flat to the beach and torso upright, assuming this position when fighting for dominance. Their skin incorporates colour changing Chromatophore cells, allowing the display of various patterns upon their huge dorsal fins.
Incidentally, this species can also emit various human like vocalisations, which, purely by chance, can sound somewhat like a small child or woman singing. They use these vocalisations to attract mates, which occurs mostly when on land. These can carry on the wind for many miles, and further underwater. This may be the source of the siren mythos.
Although not related to humans, Icthyosapien share some key evolutionary events which gave them this osteology and musculature. Very few adult specimens have ever been found, which gave rise to the "deep one" mythology found in various shunned books and manuscripts - that they may indeed dwell in subterranean cities miles below the surface. According to arcane folklore, the deep ones were fish like humanoids who serve aquatic alien gods. Although Merrylin was equally fascinated by the roots of that particular esoteric religion, he believed Icthyosapiens were of a separate species.