When morphology and molecules tell us different stories: a case-in-point withLeptodon corsicus,a new and unique endemic moss species from Corsica

Leptodon corsicus (Neckeraceae) is described as the first endemic moss species from Corsica. It strikingly differs from the other species of the genus by the lack of a dense and pinnate to bipinnate mode of branching; about 10 times smaller shoots that do not inroll upon drying; the lack of paraphyllia; and few, occasional small pseudoparaphyllia. Due to its small size and several leaf characters, L. corsicus shares at first glance more similarities with Homalia webbiana and Neckera besseri than with Leptodon. Yet, phylogenetic analysis of chloroplast and nuclear DNA sequences unambiguously shows that L. corsicus is deeply nested within L. smithii. The numerous morphological characters that distinguish L. corsicus from L. smithii cannot be attributed to plasticity. Consequently, we interpret the phylogenetic position of L. corsicus as the result of a recent speciation process, involving mutations at one or a few coding loci or differences in gene expression, which have tremendous consequences for...