JOTOKI

 Art by Souhjiro, copyright © 2009

(Note: no hyperlink was given to the author of this image on the site on which it was found. To anybody who has these informations, please froward them so that they may be added here. Thanks!)

Jotoki are non-humanoid sentient communal organisms that developed a space faring civilisation.
The Jotoki resemble large, spindly starfish. They are born as small aquatic swimmers, most of which are eaten by predators; in time, survivors will merge in groups of five to form one collective organism, which grows into an arboreal creature; its tails become arms, and its fins differentiate into fingers. When it grows large enough, the Jotok imprints itself on an adult and enters a stage of rapid learning and brain growth. A Jotok who desires a family can simply go into the wilderness and "harvest" an adolescent. Unimprinted adult Jotoki are considered feral, and regarded as little more than animals. Since the five subunits that make up one Jotok individual are not necessarily genetically related, reproduction does not require sex; a Jotok can simply find a pond and deposit its offspring to begin the cycle again.
The Jotoki were experts at trade. Their interstellar trade empire was quite developed for its time, but when the Jotoki attempted to use the Kzin as mercenaries, the Kzin revolted and conquered the Jotoki. Before their enslavement, Jotoki operated in groups called "clanpods", as part of their former planet-wide tradeweb. Details of this arrangement are not known. Jotok technological specialties included gravity polarizers, linguistics and biotechnology. They had the ability to force-grow clones to adulthood. The Kzinti believe that there is a free Jotoki fleet wandering amongst the stars, which would have provided their most strenuous opposition.
After the Man-Kzin Wars, humans recovered some Jotoki swimmers in an attempt to breed a free Jotok species.
Source: Larry Niven, Known Space Universe, (informations adapted from the Wikipedia entry), "The Asteroid Queen", by Jerry Pournelle and S.M. Stirling, "In The Hall of the Mountain King", by Jerry Pournelle and S.M. Stirling, "The Heroic Myth of Lieutenant Nora Argamentine", by Donald Kingsbury

PIERIN

Planet of Origin: Pierin, in the Reticulus constellation
A bipedal species that developed a small spacefaring civilisation and was enslaved by the Kzin. Pierin are nosy horned avians with wide wings. They speak in raspy screeches and atonal clicks which are difficult to understand for other species.
SOurce: Larry Niven, Known Space universe, The Ringworld Companion (a supplement for the Ringworld Roleplaying Game) pp. 18-9

KDATLYNO

Planet of Origin: Kdat
Kdatlyno are an extraterrestrial species which was conquered by the Zkin before they entered the space age. After their liberation from the Kzin, they established themselves on several worlds. They are a ten feet tall massive and powerful bipeds with muscular build, long arms and flat feets, urved silver-tipped claws at knees and elbows, rough scaly brownish skin, retractile claws on the knuckles of their huge hands. They have no eyes but a goggle-shaped tympanum and constantly emit a supersonic whistle through their large mouth, having evolved echolocation rather than vision.
They are famous for their touch-sculptures Source: Larry Niven, Known Space universe, Grendel (short story), in Neutron Star Picture by Bonnie Dalzell, Copyright © 1975

STARSEEDS

Starseeds are lifeforms found through interstellar space. They seem to migrate from the galactic core toward the rim, ejecting their eggs along the way, and then back to the core. Sometimes the eggs are ejected towards other galaxies, but most are left to hatch and migrate themselves to the core.

When folded on themselves, they look like a spherical mass roughly a mile in diameter, but when in need of changing direction, they unfold into a large squarish solar sail with its corners connected via strands to a small knob. Most of the internal organs are located in a cross-shaped swelling in the sail.

Source: Larry Niven, A gift from Earth