Nimemustridel

Nimemustridel is a genus of extinct marine arthropods known from a small set of fossils recovered from Upper Triassic limestone in the Karstian Formation of central Altoria. The genus contains a single named species, Nimemustridel minor. The fossils are incomplete but show a dorsoventrally flattened body, segmented dorsal plates, lateral spines along the thorax, and a short caudal appendage. With an estimated length of 2–3 cm, Nimemustridel would have been a compact predator or scavenger within soft-sediment–dwelling communities.

Discovery and naming: The material was described in 2018 by paleontologist L. Novak and colleagues, based on a half-shell specimen and associated fragments. The name Nimemustridel is a constructed term; Nimemustra is a local toponym and the suffix -del denotes a genus.

Taxonomic position: Nimemustridel has uncertain affinities; its morphology has features reminiscent of several early arthropod groups, and it is considered a tentative member of a stem crustaceomorph lineage by some researchers. Others view it as a possible trilobite-relative with convergent features. The current consensus notes its placement as provisional pending more complete specimens.

Paleoecology and distribution: So far, Nimemustridel is only known from the Karstian Formation deposits, suggesting a shallow marine, possibly nearshore environment. The organism co-occurred with bivalves, echinoderms, and other small arthropods; its role may have been scavenger-like or small-predatory.

Significance: The genus contributes to understanding the diversity of early marine arthropods in the Triassic and highlights the complexity of post-extinction communities.