# Proposal of Limosilactobacillus secundus sp. nov., Limosilactobacillus reuteri subsp. pararodentium subsp. nov., Limosilactobacillus reuteri subsp. peregrinus subsp. nov. and Limosilactobacillus reuteri subsp. simiae subsp. nov., isolated from the gastrointestinal tract of vertebrate hosts

## TL;DR

This paper proposes new species and subspecies of Limosilactobacillus bacteria found in the guts of vertebrates, improving our understanding of their genetic diversity and host adaptations.

## Contribution

The paper introduces a novel species and three novel subspecies of Limosilactobacillus based on phylogenomic analysis of gut isolates.

## Key findings

- Four new lineages of Limosilactobacillus reuteri were identified from rodent and primate gut samples.
- Genetic divergence was confirmed using average nucleotide identity and digital DNA–DNA hybridization.
- The new taxonomic framework enhances understanding of host adaptations in Limosilactobacillus.

## Abstract

A core genome-based phylogenomic analysis of representative strains of the species Limosilactobacillus reuteri identified eight lineages that differ from the six previously described L. reuteri subspecies. Four of them are represented by isolates obtained from intestinal digesta or faeces of rodents and primates, including strains LR77T and LR80 (lineage X), mlc3T and LR92 (lineage VIII), LR51T and LR88 (lineage VII) and LR66T and LR52 (lineage IX). Analyses of pairwise average nucleotide identity and digital DNA–DNA hybridization values further support their genetic divergence from existing L. reuteri subspecies. These findings suggest the classification of these four lineages as one novel species of Limosilactobacillus and three new subspecies of L. reuteri. Therefore, we propose the novel species Limosilactobacillus secundus sp. nov. (type strain LR77T=DSM 113335T=LMG 32469T) and the novel subspecies L. reuteri subsp. pararodentium subsp. nov. (type strain mlc3T=DSM 113337T=LMG 32470T), L. reuteri subsp. peregrinus subsp. nov. (type strain LR51T=DSM 113336T=LMG 32467T) and L. reuteri subsp. simiae subsp. nov. (type strain LR66T=DSM 113334T=LMG 32468T). This expanded taxonomic framework enhances our understanding of the genetic diversity of L. reuteri and further supports its adaptations to diverse vertebrate hosts.