# Pisinnocaris subconigera—a valid species of early Cambrian fuxianhuiid

## TL;DR

This study confirms that Pisinnocaris subconigera is a distinct species of early Cambrian fuxianhuiid, not a juvenile form of another species.

## Contribution

The study provides new morphological evidence supporting the taxonomic validity of Pisinnocaris subconigera.

## Key findings

- P. subconigera has four short prothoracic segments with biramous appendages.
- It has four opisthothoracic segments with four pairs of appendages and four limbless abdominal segments.
- Both small and large individuals show consistent morphology, ruling out a juvenile identity.

## Abstract

Pisinnocaris subconigera was first described as a rare, small euarthropod from the early Cambrian Chengjiang biota, southwestern China. The taxonomic validity of this species was later challenged due to the lack of essential morphological details to differentiate it from Fuxianhuia protensa, especially from the juvenile perspective. Here, we examined the holotype and additional specimens of P. subconigera with multiple imaging techniques, such as microscope optical imaging, micro-CT scanning and computer-based 3D rendering, and revealed the previously unknown ventral organization of P. subconigera. New findings include four short prothoracic segments each bearing a pair of biramous appendages, four opisthothoracic segments each with four pairs of appendages, and four limbless abdominal segments. Both the small and large individuals exhibit unique and consistent morphological characteristics, indicating that P. subconigera does not represent the larval or juvenile form of any fuxianhuiid as previously proposed. Combined with phylogenetic analyses, our study suggests that P. subconigera remians as a valid member of the early Cambrian fuxianhuiids.