An alien in need of protection: Telaranea murphyae Paton

1. England’s rare mosses and liverworts 

 By Ron D. Porley

The 1048-species bryophyte flora (752 mosses, 292 liverworts and 4 hornworts) of the British Isles is the best mapped of anywhere in the world. England alone has 666 mosses and 252 liverworts, and Porley presents an account of 87 (9%) of these, including conservation status, common names, distribution maps, morphology and habitat.  Critically, he raises the issue of conservation of genetic variation. Increasingly, published and unpublished molecular studies on bryophytes reveal astonishing levels of genetic diversity in apparently morphologically homogeneous taxa, so-called cryptic and semi-cryptic species (e.g. liverworts, Diplasiolejeunea and Dumortiera, and mosses, Pyrrhobryum mnoides and Scleropodium).

            This book is a mine of information for population genetic studies on rare English bryophytes, and provides a valuable model for other countries.

2. An alien in need of protection: Telaranea murphyae Paton

Two Telaranea species are currently on the British red list (updated by Porley 2013): T. europae Engel & Merr. (formerly misidentified as the non-European T. nematodes, see Engel & Merril 2004), and T. murphyae, a new addition to the list. This latter species is in the curious position of being both non-native in, and endemic to, England: It has been only found in Tresco and St. Mary’s, Isles of Scilly, and in two closely neighbouring locations on the mainland, Branksome Chine, Poole, Dorset and Alum Chine, Bournemouth, S. Hampshire (see the local flora by D. Holyoak).

 

Extracted from the Liverwort flora of the British Isles by J. Paton (1999),
 Harley Books

            Telaranea murphyae is dioicous. It was described by Jean Paton in 1965, based only on male plants. Its restricted habitat (in or near botanic gardens) suggests that the species was introduced on imported plants. Its affinities and taxonomic status have been much discussed, including Paton (1992), Grolle & Long (2000); Engel & Merril 2004, and Cooper et al. 2013. 

In a recent monograph of Telaranea, Engel and Merril (2004) maintain the status of T. murphyae based chiefly on the position and appearance of its androecia. Confusing the issue somewhat, more recently the species was transferred to Tricholepidozia by Cooper et al. (2013), in a paper that includes a comprehensive phylogeny of the subfamily Lepidozioideae, with Lepidozia, Telaranea, Kurzia and related genera (Cooper et al.2012). However, the transfer was not based on genetic evidence, as Telaranea /Tricholepidozia murphyae (Paton) E.D. Cooper has not been included in molecular studies.

This species, unlike any other bryophyte on the British Red List, is regarded as non-native, of unknown origin. Since the species is non-native it is not a priority species on the UK Biodiversity Action Plan (BAP http://jncc.defra.gov.uk/page-5168), and there are no conservation measures for it. However until it is found in its country of origin, wherever that might be, the UK bears sole responsibility for its preservation (effectively ex situ), as all known material of the plant occurs in these two locations in the south of England. Molecular sampling to elucidate the origin and affinities of this enigmatic, non-native UK endemic would assist prioritization of conservation efforts. The RBGE British bryophyte barcoding programme (e.g. http://www.knowledgescotland.org/briefings.php?id=146), which currently only has DNA from one accession of T. europae and two of T. tetradactyla, is unlikely to provide answers as this is definitely a question that needs to be addressed with a more global sampling effort.

Thanks to Laura Forrest (RBGE) for lending me the book and for comments on this blog.