Molecular identification and diversity assessment of Tyrrhenian Romulea species (Iridaceae)
Abstract
Taxonomic assignments based only on morphology are often insufficient for delimiting species, particularly in complexes shaped by hybridization and polyploidy, where species boundaries are unclear. This limitation hinders progress in ecological, biogeographic and conservation research. The genus Romulea, distributed across Africa and the Mediterranean Basin, exemplifies this challenge. Despite its remarkable diversity, Mediterranean Romulea has not received much attention from genetic and molecular studies. Here, we present the first multilocus genotype analysis of Mediterranean Romulea taxa, focusing on the Tyrrhenian biogeographic province. Using target-capture sequencing with the universal Angiosperms353 kit, we generated genomic data for 272 individuals representing 18 putative taxa. Our findings reveal genetic groups that align with current taxonomy, the existence of cryptic divergence, and highlight the role of hybridization. Furthermore, analysis of intraindividual genetic diversity suggests one or several allopolyploid origins for Mediterranean Romulea. Four taxa (R. assumptionis, R. revelieri, R. ligustica, R. rollii) are consistently well differentiated across nuclear and plastid datasets, supporting their recognition as distinct species. In contrast, the widespread species R. ramiflora and R. columnae contain well-differentiated groups that may represent cryptic speciation.
Several other taxa, including R. x melitensis, R. corsica, and R. bulbocodium, exhibit genomic signatures consistent with hybrid origins. Plastid and nuclear variation patterns are consistent with a hypothesis of rapid radiation in the Tyrrhenian region.
These results provide a primary genomic framework for the integrative taxonomy of Romulea.
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BibTeX
@article{baumel2026molecular,
title = {{Molecular identification and diversity assessment of Tyrrhenian Romulea species (Iridaceae)}},
author = {Alex Baumel and Virgile Noble and Cyllène Chatellier and Juan Viruel and Stephen Mifsud and Henri Michaud and Alain Delage and Lisandru Leandri and Andrea Lallai and Gianluca Iiriti and Gianniantonio Domina and Gabriele Casazza and Pere Fraga-Arguimbau and Baptiste Pierre and Anouar Toumi and Frédéric Médail},
journal = {PLoS ONE},
year = {2026},
month = sep,
doi = {10.1371/journal.pone.0358245},
url = {https://hal.inrae.fr/hal-05761473v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Molecular identification and diversity assessment of Tyrrhenian Romulea species (Iridaceae)
AU - Alex Baumel
AU - Virgile Noble
AU - Cyllène Chatellier
AU - Juan Viruel
AU - Stephen Mifsud
AU - Henri Michaud
AU - Alain Delage
AU - Lisandru Leandri
AU - Andrea Lallai
AU - Gianluca Iiriti
AU - Gianniantonio Domina
AU - Gabriele Casazza
AU - Pere Fraga-Arguimbau
AU - Baptiste Pierre
AU - Anouar Toumi
AU - Frédéric Médail
PY - 2026
DA - 2026/09/15
JO - PLoS ONE
DO - 10.1371/journal.pone.0358245
UR - https://hal.inrae.fr/hal-05761473v1
AB - Taxonomic assignments based only on morphology are often insufficient for delimiting species, particularly in complexes shaped by hybridization and polyploidy, where species boundaries are unclear. This limitation hinders progress in ecological, biogeographic and conservation research. The genus Romulea, distributed across Africa and the Mediterranean Basin, exemplifies this challenge. Despite its remarkable diversity, Mediterranean Romulea has not received much attention from genetic and molecular studies. Here, we present the first multilocus genotype analysis of Mediterranean Romulea taxa, focusing on the Tyrrhenian biogeographic province. Using target-capture sequencing with the universal Angiosperms353 kit, we generated genomic data for 272 individuals representing 18 putative taxa. Our findings reveal genetic groups that align with current taxonomy, the existence of cryptic divergence, and highlight the role of hybridization. Furthermore, analysis of intraindividual genetic diversity suggests one or several allopolyploid origins for Mediterranean Romulea. Four taxa (R. assumptionis, R. revelieri, R. ligustica, R. rollii) are consistently well differentiated across nuclear and plastid datasets, supporting their recognition as distinct species. In contrast, the widespread species R. ramiflora and R. columnae contain well-differentiated groups that may represent cryptic speciation. Several other taxa, including R. x melitensis, R. corsica, and R. bulbocodium, exhibit genomic signatures consistent with hybrid origins. Plastid and nuclear variation patterns are consistent with a hypothesis of rapid radiation in the Tyrrhenian region. These results provide a primary genomic framework for the integrative taxonomy of Romulea.
SN - 1932-6203
SN - 1932-6203
ER -