TY - JOUR

T1 - Complete mitochondrial genomes from museum specimens clarify millipede evolution in the Eastern Arc Mountains

AU - Nielsen, Martin

AU - Margaryan, Ashot

AU - Nielsen, Tejs Lind

AU - Enghoff, Henrik

AU - Allentoft, Morten E.

PY - 2022

Y1 - 2022

N2 - The Eastern Arc Mountains in Tanzania represent a hotspot for biological diversity of global importance. The level of endemism is high, and Eastern Arc biodiversity has been studied extensively in vertebrates and invertebrates, including millipedes. However, millipede evolution is vastly understudied at the molecular level. Therefore, we used next-generation 'shotgun' sequencing to obtain mitochondrial genome sequences of 26 museum specimens, representing six genera and 12 millipede species found across the Eastern Arc Mountains. Bayesian and maximum likelihood methods yielded consistent topologies with high node support, confirming a high level of congruence between molecular and morphological analyses. The only exception was a Tropostreptus sigmatospinus individual from Zanzibar, which was placed outside an otherwise monophyletic group consisting of mainland individuals of the same assumed species. For two species with a distribution across several mountain blocks (Tropostreptus sigmatospinus and Tropostreptus hamatus), each mountain population represents a distinct monophyletic lineage. In contrast, we also observe that distinct species exist sympatrically in the same montane forests, indicative of older speciation events that are not defined by current forest distribution. Our results are important for understanding speciation mechanisms in montane rain forests and highlight that ethanol-preserved invertebrates exhibit a tremendous potential for genomic analyses.

AB - The Eastern Arc Mountains in Tanzania represent a hotspot for biological diversity of global importance. The level of endemism is high, and Eastern Arc biodiversity has been studied extensively in vertebrates and invertebrates, including millipedes. However, millipede evolution is vastly understudied at the molecular level. Therefore, we used next-generation 'shotgun' sequencing to obtain mitochondrial genome sequences of 26 museum specimens, representing six genera and 12 millipede species found across the Eastern Arc Mountains. Bayesian and maximum likelihood methods yielded consistent topologies with high node support, confirming a high level of congruence between molecular and morphological analyses. The only exception was a Tropostreptus sigmatospinus individual from Zanzibar, which was placed outside an otherwise monophyletic group consisting of mainland individuals of the same assumed species. For two species with a distribution across several mountain blocks (Tropostreptus sigmatospinus and Tropostreptus hamatus), each mountain population represents a distinct monophyletic lineage. In contrast, we also observe that distinct species exist sympatrically in the same montane forests, indicative of older speciation events that are not defined by current forest distribution. Our results are important for understanding speciation mechanisms in montane rain forests and highlight that ethanol-preserved invertebrates exhibit a tremendous potential for genomic analyses.

KW - Diplopoda

KW - mitogenomes

KW - museomics

KW - shotgun sequencing

KW - Tanzania

KW - DNA

KW - DIPLOPODA

KW - SPIROSTREPTIDA

KW - GENUS

KW - SPECIATION

KW - PHYLOGENY

KW - HISTORY

KW - LABOULBENIALES

KW - BIOGEOGRAPHY

KW - CHAMELEONS

U2 - 10.1093/zoolinnean/zlac058

DO - 10.1093/zoolinnean/zlac058

M3 - Journal article

VL - 196

SP - 924

EP - 939

JO - Zoological Journal of the Linnean Society

JF - Zoological Journal of the Linnean Society

SN - 0024-4082

IS - 2

ER -