Fissidens eremicus (Fissidentaceae), a new pseudocryptic African–European species with dimorphic stems

Abstract

Within Fissidens subgenus Fissidens, several species are distinguished in Europe. Some of them are easily identifiable by their morphological characters, and others by a combination of these characters and their sexual reproduction structures. The discovery in the south of the Iberian Peninsula of collections similar to F. viridulus (Sw.) Wahlenb. but with dimorphic fronds (male and female plants) like those of F. sublimbatus Grout suggests that an undescribed taxon exists in this region. Nuclear ITS sequences of four samples of this hypothetical new species from southern Spain and 28 specimens of other species of the subgenera Fissidens and Pachyfissidens were studied. Relationships between specimens were explored with maximum likelihood and Bayesian inference analysis. A morphological study comparing the material to F. sublimbatus was also made. Molecular data showed high support for the recognition of a new species that also presents some morphological differences from Fissidens sublimbatus. Consequently, F. eremicus J.Guerra & J.A.Jiménez has been here described as a new species that can be considered as pseudocryptic and is readily confused with F. sublimbatus. This new taxon is known from the Canary Islands, North Africa and south-southeast Spain, colonising loamy-calcareous soils in ravines of places that are generally neither arid nor subject to much rain.