These guys are the fifth species of sapient alien in Runaway to the Stars. The RttS “plot” is very loose right now, being my most recent project, but these fellows will be discovered during the story. How first contact is handled with them (vs the disaster that was first contact with centaurs) will be a big plot point. They’re usually called scuds (a common name for earth’s amphipods) but have several other nicknames.

Scuds are sapient semi-aquatic creatures who live in inter-tidal zones. Their industry is at an equivalent level to 1970s human civilization, and is divided over both land and sea depending on need (you can’t smelt metal underwater, for example). They can breathe fine out of water as long as they keep their gills wet, but are most comfortable submerged in the ocean. Most of the transport infrastructure they have built onto land are railways with cars full of baffled seawater.

Scuds are technically a bisex species, but reproductively speaking are more like ferns than any earth animal. They have two different forms, haploid and diploid. The diploid stage is sapient, about 2.5 feet tall, and egg laying. The haploid stage is a microscopic plankton with two sexes. Diploid scuds release haploid scuds in a sort of bi-monthly “period,” which then float around gathering nutrients in the ocean before mating with another haploid and trying to find a diploid scud to impregnate before they die. From the perspective of diploid scuds, they are essentially wind pollinated. Because of this system, genetic inheritance is almost entirely determined by local currents. Most of the plankton in their planet’s ocean is made up of similar haploid stages of bigger sea creatures, sort of like how some of our plankton eventually turns into big ol’ crabs and stuff.

Diploid scuds usually live together in bonded pairs or trios, where their reproductive cycles naturally alternate and they help take care of each other’s young. Scud eggs usually come in clutches of 4-6 soft eggs that they stick to their 4 rear swimmer legs with a natural adhesive.

Scud language is a mixture of sound and visuals. They create noise through stridulation, mostly clicking their bill and rubbing the joints in their antenna together. While speaking they will also wave their antenna like little semaphore flags, which depending on the specific language can indicate anything from tone to verb tense.