#bryozoa

Poster on bryozoan awareness I made for my marine biology class, figured it might be appreciated here

Plate IX Animal Mousse / Animal Moss (Flustra cormata)

from Alfred Moquin-Tandon’s Le monde de la mer (The World of the Sea), 1866 (English ed. 1869)

Via BHL

(sources - 1, 2, 3, 4)

Bryozoa is a phylum of animals that, like many Cnidarians, live in colonies of cloned zooids that make up a larger organism, though some solitary species exist. They are commonly known as “Moss Animals”. Each individual bryozoan is usually about half a millimetre long. Colonies of bryozoans can take a variety of forms, including mats, fans, bushes, crusts, and balls. All bryozoans are filter feeders, using a crown of tentacles called a lophophore which surrounds a mouth. Most live in tropical saltwater, but some also live in oceanic trenches, polar seas, brackish water, and freshwater. 5,869 living species of bryozoan are known.

In a colony of bryozoans, there are different types of zooids responsible for different functions. All bryozoans will have autozooids (seen in the first image), which are responsible for feeding, excretion, and supplying nutrients to the rest of the colony. Some species have specialist zooids, including hatcheries for fertilized eggs, defense structures, root-like attachment structures, and/or spiny defensive zooids that are used as legs to slowly creep along. Each zooid consists of a cystid, which provides the body wall and produces an exoskeleton, and a polypide, which holds the organs. Each colony grows by asexual budding from a single zooid known as the ancestrula. Most start life as males, later changing to female, though colonies will always contain a balanced ratio of males and females. Although the zooids themselves are microscopic, colonies can range in size from 1 cm to over 1 m (3 ft 3 in).

Propaganda under the cut:

Mollusca: Snails, slugs, cephalopods, bivalves, chitons, limpets, and others. This group contains the largest invertebrates, the giant and colossal squids. They are the largest marine phylum, but many members are terrestrial. Although they are incredibly diverse in body shape, all Molluscs generally have a hard "radula" used for eating, a mantle that may secrete a hard shell, and a body mostly composed of dense muscle. These animals can be predators, herbivores, filter feeders, symbiotic, and even parasitic. This phylum exhibits remarkable diversity overall.

Bryozoa. This phylum is made up of tiny aquatic invertibrates that mostly live in sedentary colonies

Rotifer. This phylum is made up of microscopic aquatic animals with a cilliated corona sourrounding the mouth

Basically the rough idea was that, very distant in Earth's future, the zooids within a bryozoan colony will each become so remarkably specialized that they basically end up turning into cells/organs of one single animal. Zooids for stuff like muscles and circulation and communication would evolve. Each zooid wouldn't individually feed with a lophophore and instead the whole recursive animal would have a mouth, gut, and anus made up of specialized zooids. Stuff like that.

This drawing is months old and was merely concept exploration. I didn't actually know much about bryozoans at the time, let alone how their morphology and colony structure should dictate the design of such a recursive animal. I still don't really know a whole lot. But one day I hope that I do and I can actually make well informed designs for recursive animals.

This little guy in the drawing was specifically supposed to be a "basal" recursive animal, only a half centimeter long or so, which would crawl along the seafloor in search of any detritus to rake up with its rasping apparatus. Said apparatus, plus the numerous spines jutting out its body, being made of "defensive zooids" that are basically just hardened spikes. It would have a rather simple musculature that let it slug its way around. I hadn't thought much about sensory features, though I imagined it being a deep water organism that makes it homes around hydrothermal vents, so eyes weren't much a concern. The last thing is that, immediately behind the body spikes, are numerous "conventional" looking lophophores--but, rather than collecting food, they aid in respiration thanks to the increased surface area they provide. Rather foolishly, I used the horseshoe-shaped lophophores of phylactolaemata, even though this would definitely be a marine species, and moreover one with calcified cystid walls. As for whether this recursive animal would instead descend from gymnolaemata or stenolaemata, or perhaps even something entirely novel, I have no clue at this point. I don't have enough knowledge on bryozoans to make that sort of decision right now.