Arctomia insigna (P.M. Jørg. & Tønsberg) Ertz 2017

Ertz, Damien, Poulsen, Roar S., Charrier, Maryvonne & Søchting, Ulrik, 2017, Taxonomy and phylogeny of the genus Steinera (Arctomiales, Arctomiaceae) in the subantarctic islands of Crozet and Kerguelen, Phytotaxa 324 (3), pp. 201-238 : 231

Arctomia insigna (P.M. Jørg. & Tønsberg) Ertz comb. nov.

MycoBank: MB 822687

Basionym: Leptogium insigne P.M. Jørg. & Tønsberg, Bibliotheca Lichenologica 104: 242 (2010). Type:— USA. Washington, Lane Co., near mouth of Gwynn Creek on Pacific Ocean, 44°17’N, 124°06’W, 10 m, on leaning Alnus trunk in forest, 23 February 1996, B. McCune 23460 (holotype OSC, isotype BG, not seen).

Synonym: Arctomia borbonica Magain & Sérus., MycoKeys 4: 16 (2012). Type:— REUNION. Forêt de Bébour, track starting at Gîte de Bélouve toward Piton des Neiges, 21°4’49”S, 55°31’24”E, 1850 m, 9 November 2009, N. Magain & E. Sérusiaux sn (holotype LG, not seen).

Notes: A nuLSU sequence of the type specimen of Leptogium insigne P.M. Jørg. & Tønsberg (2010: 242) (EU166329: USA, Oregon, McCune 23460) deposited on GenBank in 2007 and apparently unpublished, was found to be nearly identical (four nucleotides different, less than between the two nuLSU of A. borbonica from Reunion that have 7 different nucleotides) to the two nuLSU sequences of Arctomia borbonica published by Magain & Sérusiaux (2012). This supports the conclusions of Jørgensen & Palice (2016) who found A. borbonica to be a synonym of Leptogium insigne based on morphological studies. These authors did not change the generic placement of L. insigne arguing that further studies are necessary to establish the generic structure in the Arctomiaceae . They suggested that a separate genus might be established for it, mainly because of the different thallus anatomy compared to the type of Arctomia . However, according to our phylogeny (Fig. 2), further generic splitting of Arctomia does not seem appropriate. Leptogium insigne is nested in the genus Arctomia as currently circumscribed making a new combination in Arctomia reasonable, especially as the type species of Leptogium ( L. azureum (Sw.) Mont. ) belongs to the Collemataceae ( Otálora et al. 2014) . According to Otálora et al. (2014:285), the generic name Gabura Adans. is a threat to the younger name Arctomia Th. Fr. In order to avoid the synonymisation of the well-known genus Arctomia , currently the type of the family Arctomiaceae and the order Arctomiales , Arctomia should preferably be conserved against Gabura .