Soriparasites

Soriparasites are an extant group of superficially lizard-like carpozoan fauna. As their name suggests, they are an ancient group of shrews which ancestrally had a parasitic lifestyle.

History
Soriparasites are an extremely basal offshoot of the first shrews, having evolved during the very first radiation of the group to feast on the blood of their relatives. In the Allenian period, the Death Soriparasite evolved and infamously spread a deadly plague that wiped out most other shrews of the time. Though the death soriparasite perished as it lost all its hosts, other soriparasites survived and lived on.

In the Martykian period, the Desert Soriparasite, the first soriparasite to have modern jaw anatomy, evolved. By luck, it happened to have colonized a cave by the time of the gamma ray burst a few million years later.

The surviving desert soriparasites proceeded to never leave their cave, partly because it was cut off from the outside world. They just stayed in there, unchanging, feeding on the blood of earbacks as numerous ecological shifts and mass extinction events happened on the surface above.

It wasn't until over 100 million years later, in the Darthian period, that the soriparasites were brought back to the outside world by their adventurous hosts. This produced the living fossil Lazarus Soriparasite, which is the ancestor of all modern species.

Diversity
There are two distinct kinds of soriparasites, the extinct basal forms which had huge teeth on both jaws to induce massive bleeding, and the extant modern forms which essentially suckle blood from relatively small scratches they inflict on their hosts. Living species range in size from the 16-centimeter long Eggslurping Sorite to the 2-centimeter long Leaping Soriparasite. Prior to modern forms, the largest soriparasite had been the 15-centimeter long Alpine Soriparasite.