# A New Record of Pogonatum tahitense (Polytrichaceae) from Tibet, China: Taxonomic Description, Range Expansion, and Biogeographic History

## TL;DR

A new record of the moss species Pogonatum tahitense is found in Tibet, China, expanding its known range and providing insights into its evolutionary history.

## Contribution

The first mainland China record of Pogonatum tahitense, supported by morphological and molecular evidence, and its Pleistocene origin inferred through phylogenetic analysis.

## Key findings

- Pogonatum tahitense was confirmed in Tibet, China, through morphological and molecular analysis.
- The species is dated to have originated in Tibet during the Pleistocene, around 1.8 million years ago.
- Ancestral range analysis supports a Tibetan origin for P. tahitense.

## Abstract

The genus Pogonatum stands out as the most diverse within the family Polytrichaceae, encompassing over 50 species. Pogonatum tahitense has been recorded across various Pacific regions, including Hawaii in the United States and Tahiti in French Polynesia, as well as in Asia, such as in Taiwan in China, Java in Indonesia, and Sabah in Malaysia. In the current study, a specimen collected in Tibet, China, is described, confirming its taxonomic classification as P. tahitense through a comprehensive analysis integrating morphological evidence and molecular study based on sequences from the plastid (rbcL, rps4, trnL-F), mitochondrial (nad5), and nuclear (ITS2) regions. This documentation represents the first record of the species within mainland China. A time-calibrated, molecular-based phylogenetic analysis was conducted, employing various approaches for ancestral range inference. The findings suggest that P. tahitense originated during the Pleistocene epoch, approximately 1.8 mya, in Tibet, China.