# Aleuritopteris hainanensis (Pteridaceae), a New Species From Hainan, China

## TL;DR

Scientists discovered a new fern species in China that looks similar to another species but has distinct physical and genetic traits, and it is at risk of becoming endangered.

## Contribution

The discovery and formal description of a new fern species, Aleuritopteris hainanensis, based on morphological and genetic evidence.

## Key findings

- Aleuritopteris hainanensis differs from A. squamosa in frond length and scale morphology.
- Genetic analysis shows significant divergence between A. hainanensis and A. squamosa.
- The species is proposed to be classified as Vulnerable (VU) under IUCN criteria.

## Abstract

Aleuritopteris hainanensis, a new fern of Pteridaceae from Hainan Province, China, is described and illustrated. Morphologically,
A. hainanensis
closely resembles
A. squamosa
, with both species bearing densely scaly fronds. However, the fertile fronds of
A. squamosa
(10.7–25.9 cm) are significantly longer than the sterile fronds (4.1–10.7 cm), whereas in
A. hainanensis
, the sterile (9.4–13 cm) and fertile fronds (10.1–14.1 cm) are nearly equal in length. In addition, the stipe and abaxial lamina scales of
A. hainanensis
are broadly lanceolate with nearly entire margins, while those of
A. squamosa
are lanceolate with margins erose‐serrulate. Plastomes analysis futher reveals that the genetic distance between
A. hainanensis
and
A. squamosa
is significantly greater than the typical intraspecific variation, supporting the recognition of
A. hainanensis
as a distinct species. According to IUCN criteria, we propose that
A. hainanensis
should be categorized as a Vulnerable (VU) species.

A new fern species, Aleuritopteris hainanensis, is described from Hainan Province, China, closely resembling
A. squamosa
but differing in fertile/sterile frond length and scale morphology. Plastome analysis confirms its distinctness, showing significant genetic divergence from
A. squamosa
. The species is proposed to be classified as Vulnerable (VU) under IUCN criteria.