# Carya luodianensis (Juglandaceae), a New Species From Guizhou Province, Southern China, Revealed by Morphological and Plastid Evidence

## TL;DR

A new species of Carya, Carya luodianensis, is identified in China using both physical traits and genetic analysis.

## Contribution

The discovery and description of a new Carya species supported by morphological and plastid genomic data.

## Key findings

- Carya luodianensis is distinct from C. kweichowensis based on morphology and phylogenetic analysis.
- The plastome of C. luodianensis shows unique structural features like IR expansion and gene translocation.
- Comparative analyses highlight evolutionary divergence within the Carya genus.

## Abstract

Carya luodianensis Y.B. Yang & M.T. An (Juglandaceae), a new species from Luodian County, Guizhou Province, China, is described and illustrated based on morphological and molecular data. Morphologically, this species resembles C. kweichowensis but can be easily distinguished by its rusty brown buds, 5–7 leaflets, a greater number of lateral veins (12–21 pairs), pubescent anthers, and nut shell bearing four faint longitudinal ridges. Molecular phylogenetic analysis based on complete chloroplast genome sequences indicates that C. luodianensis is sister to C. kweichowensis. The plastome of C. luodianensis, with a total length of 175,255 bp, exhibits a typical quadripartite structure and consists of 78 protein‐coding genes (PCGs), 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Notably, a marked expansion of the inverted repeat (IR) region (40,956 bp) and contraction of the small single‐copy (SSC) region (3553 bp) are detected, accompanied by the translocation of several genes from the SSC region to the IR regions, resulting in increased gene copy numbers and reduced GC content. Comparative plastome analyses further reveal the conservation and differentiation between C. luodianensis and its closely related species, particularly in genome size, gene order, and repeat sequence distribution. Collectively, the unique morphological traits, plastid genome features, and phylogenetic placement strongly support the recognition of C. luodianensis as a distinct new species and highlight its evolutionary divergence within Carya.

Carya luodianensis (Juglandaceae), a new species, is described and illustrated. We combined morphological characteristics, comparative plastome analyses, and phylogenetic analysis, all of which support the recognition of C. luodianensis as a new species and highlight its evolutionary divergence within Carya.