Ecological niche comparison and molecular phylogeny segregate the invasive moss species Campylopus introflexus (Leucobryaceae, Bryophyta) from its closest relatives.

Renato Gama,Michael Stech,Jesús Aguirre‐Gutiérrez

doi:10.1002/ece3.3301

Renato Gama, Michael Stech + Show 1 more

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https://doi.org/10.1002/ece3.3301

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Abstract

The delimitation of the invasive moss species Campylopus introflexus from its closest relative, Campylopus pilifer, has been long debated based on morphology. Previous molecular phylogenetic reconstructions based on the nuclear ribosomal internal transcribed spacers (ITS) 1 and 2 showed that C. pilifer is split into an Old World and a New World lineage, but remained partly inconclusive concerning the relationships between these two clades and C. introflexus. Analyses of an extended ITS dataset displayed statistically supported incongruence between ITS1 and ITS2. ITS1 separates the New World clade of C. pilifer from a clade comprising C. introflexus and the Old World C. pilifer. Ancestral state reconstruction showed that this topology is morphologically supported by differences in the height of the dorsal costal lamellae in leaf cross‐section (despite some overlap). ITS2, in contrast, supports the current morphological species concept, i.e., separating C. introflexus from C. pilifer, which is morphologically supported by the orientation of the hyaline hair point at leaf apex as well as costal lamellae height. Re‐analysis of published and newly generated plastid atpB‐rbcL spacer sequences supported the three ITS lineages. Ecological niche modeling proved a useful approach and showed that all three molecular lineages occupy distinct environmental spaces that are similar, but undoubtedly not equivalent. In line with the ITS1 topology, the C. pilifer lineage from the New World occupies the most distinct environmental niche, whereas the niches of Old World C. pilifer and C. introflexus are very similar. Taking the inferences from ecological niche comparisons, phylogenetics, and morphology together, we conclude that all three molecular lineages represent different taxa that should be recognized as independent species, viz. C. introflexus, C. pilifer (Old World clade), and the reinstated C. lamellatus Mont. (New World clade).

Highlights

Accurate species identification is of great importance, for example, in biodiversity assessments, conservation, and to monitor species with invasive potential
Based on the ecological data, molecular analysis of extended datasets, and re-evaluation of diagnostic morphological characters using ancestral state reconstruction, we aim to conclude about species delimitations of C. introflexus and C. pilifer
The ITS2 topology supports a gradual decrease in lamellae height in C. pilifer, from long lamellae in the clades branching off first to shorter lamellae in most subclades of the Old World clade

Summary

| INTRODUCTION

Accurate species identification is of great importance, for example, in biodiversity assessments, conservation, and to monitor species with invasive potential. A morphological species concept is still most commonly employed (Shaw, 2009), but species identification is frequently hampered by relatively few and often (highly) variable morphological characters This is especially true for species of large and taxonomically complex genera such as Campylopus Brid. 1,000 to about 150 (Frahm, 1999; and references therein; Frey & Stech, 2009), the circumscription and identification of many of these species remains difficult This is especially pressing in delimiting the invasive species Campylopus introflexus (Hedw.) Brid. Based on the ecological data, molecular analysis of extended datasets (phylogenetic analysis of nuclear ITS and haplotype analysis of plastid atpB-rbcL sequences), and re-evaluation of diagnostic morphological characters using ancestral state reconstruction, we aim to conclude about species delimitations of C. introflexus and C. pilifer

| MATERIALS AND METHODS

Findings

| DISCUSSION