#Shilly worm

[sillystringguy]

I'm a lil shilly

[0ctogus]

Symsagittifera roscoffensis, or the shilly-shally worm belongs to this phylum!!!! It's an incredible animal because it has symbiotic green algae living inside of them which provide all the carbon intake it needs, so it has lost its digestive system completely! Don't underestimate this phylum!

Round 1 - Phylum Xenacoelomorpha

(Sources - 1, 2, 3)

Xenacoelomorpha is a small phylum of bilaterian invertebrates consisting of two sister groups: xenoturbellids and acoelomorphs.

These are small, flat worm-like animals found in the sediments of marine and brackish environments. Some have even been found near hydrothermal vents at depths of up to 4 km (2.5 mi). All species of Xenacoelomorph are hermaphroditic and reproduce sexually. Interestingly enough, they lack an excretory system, yet all genes related to the excretory system are present… except for Osr, which is needed for excretory system development. They also lack a coelom, or body cavity. They have a digestive system but it lacks nerve cells. All in all, a little animal someone forgot to finish.

Propaganda under the cut:

Folks I just found out about these today, uh

Check the links in the sources they can tell you more than I, I’m sure

[parakaryote]

Okay, have some fun facts about all of the small (under 1,000 known species) animal phyla that I found diving through Wikipedia.

Brachiopoda: Used to fill the position that bivalves fill now, which technically makes bivalves Brachiopoda 2.0.

Chaetognatha: Some species have an “oil vacuole” organ that might help them maintain buoyancy (basically a swim bladder). Also, some of them produce tetrodotoxin. Also also, some of them are bioluminescent.

Ctenophora: Double anuses (only recently discovered). Also, they used to have skeletons.

Cycliophora: Weirdly complex reproductive cycle involving two modes and three sexes (female / male / sexless). Would make an interesting basis for a fictional species… if you can even understand what’s going on.

Dicyemida: Alternation of generations, apparently.

Entoprocta: Organs can do a complete 180° flip in position during metamorphosis.

Gastrotricha: Live for only a few days, and their bodies are “filled with poorly differentiated connective tissue”.

Gnathostomulida: Instead of laying eggs like reasonable animals, they have their eggs straight-up BURST OUT OF THE PARENT’S BODY. (They’re fine, though.) Also, they have no (permanent?) anus.

Hemichordata: Can have a hundred pairs of gill slits.

Kinorhyncha: Retractable head.

Loricifera: Some species can survive without oxygen. Whether or not they even have mitochondria is up for debate.

Micrognathozoa: Fifteen-part jaws… on an animal that’s only 100 micrometers long. They certainly live up to their name.

Nematomorpha: Because they can influence their hosts to enter water, they help feed certain types of fish.

Onychophora: Unexpectedly complex social structure. Also, they are matriarchal (girlboss).

Phoronida: “The blood of Phoronis architecta carries as much oxygen per cm3 as that of most vertebrates; the blood’s volume in cm3 per gm of body weight is twice that of a human.”

Placozoa: Have several different types of sodium channels for some reason.

Priapulida: Very dense populations despite the small number of species.

Xenacoelomorpha: One species is photosynthetic because of symbiotic algae (also, two of the common names for that species are “mint-sauce worm” and “shilly-shally worm”).