The Lichenologist 40(5): 399–409 (2008) 2008 British Lichen Society doi:10.1017/S0024282908007937 Printed in the United Kingdom Taxonomic revision of Xanthomendoza borealis and Xanthoria mawsonii (Lecanoromycetes, Ascomycota) Louise LINDBLOM and Ulrik SØCHTING Abstract: The xanthorioid taxa Xanthomendoza borealis and Xanthoria mawsonii are revised using morphological, anatomical, secondary chemical, and molecular characters. We conclude that most specimens determined as X. mawsonii from the Antarctic are conspecific with specimens labelled X. borealis from the Northern Hemisphere. Some specimens named X. mawsonii from the Antarctic are wrongly determined specimens of Xanthoria candelaria (L.) Th. Fr, including the holotype of Xanthoria mawsonii C. W. Dodge. Accordingly, Xanthoria mawsonii C. W. Dodge is a synonym to Xanthoria candelaria (L.) Th. Fr. The only available correct name for the bipolar species, which comprises material previously determined as X. borealis and X. mawsonii, and is distinct from the more widespread taxon X. candelaria, is Xanthomendoza borealis (R. Sant. & Poelt) Søchting, Ka ¨rnefelt & S. Kondratyuk. Key words: haplotype networks, internal transcribed spacer, ITS, lichens, nrDNA, phylogeny, statistical parsimony, taxonomy, TCS, Teloschistaceae, Teloschistales Introduction The exploration of the Antarctic lichen flora has been dominated by two trends. One, represented by Carrol W. Dodge, who re- garded most taxa as a priori new and not known to science, resulted in descriptions of numerous new Antarctic endemics (Dodge 1973). The second trend was represented by authors with an intimate knowledge of Arctic taxa, who recognized in the Antarctic many species formerly known only from the Northern Hemisphere (Hertel 1987; Stenroos 1993). A critical taxonomic study of the family Teloschistaceae in Antarctica (Søchting et al. 2004) has shown that the lichen flora is more endemic and that the number of true bipolar species is lower than formerly thought. Comparisons of polar lichen floras by expe- rienced lichenologists have also revealed that some species pairs thought to be distinct polar endemics are indeed conspecific (Øvstedal & Lewis Smith 2001). Xanthoria mawsonii was described by Dodge (1948) based on material from Antarctica (King George V Land, Queen Mary Land, and Mac.Robertson Land). Because the type material was unavailable for many years and no comparison possible, Poelt and Santesson (in Poelt & Petutschnig 1992a) chose to describe a new species, Xanthoria borealis, from the Northern hemi- sphere, but they acknowledged that the two taxa could possibly be conspecific. Subse- quent authors have consistently treated them as distinct taxa. They have also been regarded as distinct from Xanthoria cande- laria, although several authors have sug- gested that X. candelaria and X. mawsonii are closely related (Castello 1995; Øvstedal & Lewis Smith 2001). The possibility that X. borealis and X. mawsonii are conspecific has been indicated indirectly (e.g. Lindblom 1997), but rarely explicitly (see Øvstedal & Lewis Smith 2001). L. Lindblom: Department of Biology, University of Bergen, P.O. Box 7800, NO-5020 Bergen, Norway. Email: [email protected]U. Søchting: Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copen- hagen Ø, Denmark.
Transcript
The Lichenologist 40(5): 399–409 (2008) � 2008 British Lichen Societydoi:10.1017/S0024282908007937 Printed in the United Kingdom
Taxonomic revision of Xanthomendoza borealis and Xanthoriamawsonii (Lecanoromycetes, Ascomycota)
Louise LINDBLOM and Ulrik SØCHTING
Abstract: The xanthorioid taxa Xanthomendoza borealis and Xanthoria mawsonii are revised usingmorphological, anatomical, secondary chemical, and molecular characters. We conclude that mostspecimens determined as X. mawsonii from the Antarctic are conspecific with specimens labelledX. borealis from the Northern Hemisphere. Some specimens named X. mawsonii from the Antarcticare wrongly determined specimens of Xanthoria candelaria (L.) Th. Fr, including the holotype ofXanthoria mawsonii C. W. Dodge. Accordingly, Xanthoria mawsonii C. W. Dodge is a synonym toXanthoria candelaria (L.) Th. Fr. The only available correct name for the bipolar species, whichcomprises material previously determined as X. borealis and X. mawsonii, and is distinct from themore widespread taxon X. candelaria, is Xanthomendoza borealis (R. Sant. & Poelt) Søchting,Karnefelt & S. Kondratyuk.
The exploration of the Antarctic lichen florahas been dominated by two trends. One,represented by Carrol W. Dodge, who re-garded most taxa as a priori new and notknown to science, resulted in descriptions ofnumerous new Antarctic endemics (Dodge1973). The second trend was representedby authors with an intimate knowledge ofArctic taxa, who recognized in the Antarcticmany species formerly known only fromthe Northern Hemisphere (Hertel 1987;Stenroos 1993).
A critical taxonomic study of the familyTeloschistaceae in Antarctica (Søchting et al.2004) has shown that the lichen flora is moreendemic and that the number of true bipolarspecies is lower than formerly thought.Comparisons of polar lichen floras by expe-
rienced lichenologists have also revealed thatsome species pairs thought to be distinctpolar endemics are indeed conspecific(Øvstedal & Lewis Smith 2001).
Xanthoria mawsonii was described byDodge (1948) based on material fromAntarctica (King George V Land, QueenMary Land, and Mac.Robertson Land).Because the type material was unavailablefor many years and no comparison possible,Poelt and Santesson (in Poelt & Petutschnig1992a) chose to describe a new species,Xanthoria borealis, from the Northern hemi-sphere, but they acknowledged that the twotaxa could possibly be conspecific. Subse-quent authors have consistently treatedthem as distinct taxa. They have also beenregarded as distinct from Xanthoria cande-laria, although several authors have sug-gested that X. candelaria and X. mawsonii areclosely related (Castello 1995; Øvstedal &Lewis Smith 2001). The possibility thatX. borealis and X. mawsonii are conspecifichas been indicated indirectly (e.g. Lindblom1997), but rarely explicitly (see Øvstedal &Lewis Smith 2001).
L. Lindblom: Department of Biology, University ofBergen, P.O. Box 7800, NO-5020 Bergen, Norway.Email: [email protected]. Søchting: Department of Biology, University ofCopenhagen, Universitetsparken 15, DK-2100 Copen-hagen Ø, Denmark.
Xanthoria borealis was recently transferredto the genus Xanthomendoza (Søchting et al.2002). As experienced investigators of theTeloschistaceae in the Antarctic and in north-ern regions of the world (see, e.g., Søchting& Olech 1995; Lindblom 1997; Søchtinget al. 2004; Lindblom 2006) and with themolecular tools now available, we wanted todetermine if the two taxa should best betreated as two species with discontinuousgeographical ranges, or as one true bipolarspecies.
The main objectives of the present projectwere to investigate whether X. borealis andX. mawsonii are distinct species, and if so, todescribe the important diagnostic charactersseparating them. As Xanthoria candelaria hasbeen considered difficult to distinguish fromthese taxa, it was also included in the study.The morphology and anatomy of a largenumber of collections labelled X. borealis, X.candelaria, or X. mawsonii were studied andselected specimens subjected to a molecularinvestigation.
Material and Methods
Morphology
This study is based on specimens labelled X. borealis,X. mawsonii or X. candelaria, from the herbaria AAS(British Antarctic Survey), BG, C, FH, GZU, LD, O,TSB, UPS (incl. the private herbarium of P. Johansson)and the private herbarium of H. C. Gjerlaug (Norway).Morphological studies were based on approximately50 specimens each of herbarium material labelled X.borealis or X. mawsonii and c. 20 specimens labelled X.candelaria, (see lists of specimens studied).
Sections for microscopy were cut from 10 specimenseach of X. mawsonii and X. borealis and three ofX. candelaria with a Reichert-Jung Cryostat 2800Frigocut-E. Measurements were made on 7·0 �m thicksections mounted in water under the light microscopeand processed using the programme NIS Elements.Photographs were taken with a Nikon DS-Fi1 digitalcamera mounted on an Olympus SZH Macroscope.Secondary chemistry was analysed with HPLC accord-ing to Søchting (1997).
DNA analysis
Recently collected material of 40 specimens labelledX. borealis, 40 specimens labelled X. mawsonii, andapproximately five each of X. candelaria and Xanthoriasp., as well as additional sequences acquired frompersonal contacts or GenBank were included in the
molecular study. Some of them were not successfullyamplified or sequenced, and thus not incorporated inthe final data matrices.
DNA extraction, PCR amplification, cleaning ofPCR products, and sequencing were performed follow-ing the methods and protocols of Lindblom & Ekman(2005) for sequences produced at the University ofBergen, or Arup (2006) for sequences produced at theUniversity of Copenhagen. The primers ITS1F-5# andITS4-3# (Gardes & Bruns 1993; White et al. 1990) wereused to amplify and sequence the total ITS (ITS1-5.8S-ITS2) from the nrDNA. Sequences were assembledand edited with Vector NTI Advance 10 (Invitrogen,Carlsbad, CA), SeqMan 4.05 (DNASTAR Inc.,Madison, WI) or Sequencher 4.8 (Gene Codes Corp.,Ann Arbor, MI). Alignments were constructed withSequencher and ClustalX 1.83 (Thompson et al. 1997)and adjusted manually. Rare haplotypes identified inthe alignments were double-checked. Sequences havebeen submitted to GenBank (Table 1).
To test the hypothesis that X. borealis and X. maw-sonii are two discontinuous taxa, an analytical methodbased on haplotype relationships was applied, the so-called statistical parsimony (Templeton et al. 1992).Xanthoria candelaria was included in the initial analyses.Haplotype networks were constructed using the soft-ware TCS 1.21 (Clement et al. 2000) under the 95%parsimony probability criterion. Gaps were treated as afifth character state, whereas IUPAC ambiguity codes(only an ‘‘N’’ was present, in two sequences) weretreated as missing data by the software.
Results
We found no morphological, anatomical, orchemical characters separating collections ofX. borealis from the Northern and X. maw-sonii from the Southern Hemispheres. Seethe species descriptions below.
In the data matrix containing X. borealisand X. mawsonii, 40 fungal nrDNA ITSsequences were included, of which 39 wereproduced in the present study (Table 1).Seven sequences of X. candelaria were gen-erated (either from collections labelled X.candelaria or from collections labelled X.mawsonii but wrongly determined) and twofrom GenBank (AJ320138 and AY081154)were included in the initial alignment. Theinitial statistical parsimony network con-structed showed that they are not closelyrelated to correctly determined collectionsof X. borealis and X. mawsonii, since theyformed two disjunctive networks, whichwere separated by >100 mutational steps(not shown).
400 THE LICHENOLOGIST Vol. 40
The final haplotype network constructedusing TCS connected 10 haplotypes in asingle network (Fig. 1). Five of the haplo-types are represented by one individual only(h6-h10). Two other haplotypes consist oftwo individuals each, one with thalli labelled
as X. borealis (h4; from Greenland andSiberia) and one with thalli labelled as X.mawsonii (h5; both from Victoria Land,Antarctica). The most common haplotype inthe data set (h1; 18 individuals) was repre-sented only by thalli labelled X. mawsonii,
T 1. Original label name, voucher information and GenBank accession numbers for ITS nrDNA sequences in the datamatrix. Sequences generated in this study are printed in bold
Xanthomendoza borealisXb1 Greenland, 1995, V. Alstrup & F. J. A. Daniels 3348 (C) EU360752Xb2 Greenland, 1995, V. Alstrup & F. J. A. Daniels 1643 (C) EU360753Xb3 Russia: Siberia, 1994, J.-E. Mattsson 276 (LD) EU360754Xb4 Greenland, 2005, U. Søchting US 10450 (C) EU360755Xb5 Greenland, 1999, E. S. Hansen, Lich. Groenl. Exs.: 824 (LD) EU360759Xb6 Norway, 2002, H. C. Gjerlaug HCG 5752 (hb. HCG) EU360760Xb7 Norway, 2002, H. C. Gjerlaug HCG 5753 (hb. HCG) EU360761Xb8 Norway, 2002, H. C. Gjerlaug HCG 5781 (hb. HCG) EU360762Xb9 Norway, 2002, H. C. Gjerlaug HCG 5781B (BG) EU360763Xb10 Norway, 2003, R. Haugan (BG) EU360764Xb11 Norway, 2003, H. H. Blom (BG) EU360765Xb12 Norway, 1995, R. Haugan & E. Timdal 8062 (O) EU360766Xb13 Russia: Siberia, 1998, N. Matreeva (M) EU718623Xb14 Greenland, 2005, U. Søchting US 10499 (C) EU718624Xanthoria mawsoniiXm2 Antarctica: Victoria Land, 1993–1994, R. Bargagli, A542/21439 (TSB) EU360734Xm3 Antarctica: Ross sector, 1995, R. I. L. Smith 9768 (AAS) EU360735Xm4 Antarctica: Ross sector, 1995, R. I. L. Smith 9535 (AAS) EU360736Xm5 Antarctica: Ross sector, 1996, R. I. L. Smith 9859 (AAS) EU360737Xm6 Antarctica: Ross sector, 1995, R. I. L. Smith 10213 (AAS) EU360738Xm7 Antarctica: Victoria Land, 1996, F. Bersan A819, 30432 (TSB) EU360739Xm8 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC1 (TSB) EU360740Xm9 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC5 (TSB) EU360741Xm10 Antarctica: Ross sector, 1995, R. I. L. Smith 9721 (AAS) EU360742Xm11/Xm1 Antarctica: Victoria Land, 1993–1994, R. Bargagli A634/21301 (TSB) EU360743Xm12 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC9 (TSB) EU360744Xm13 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC6 (TSB) EU360745Xm14 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC4 (TSB) EU360746Xm15 Antarctica: Ross sector, 1996, R. I. L. Smith 10164 (AAS) EU360747Xm16 Antarctica: Victoria Land, 1989, P. Modenesi A242/12241 (TSB) EU360748Xm17 Antarctica: Ross sector, 1995, R. I. L. Smith 9590 (AAS) EU360749Xm18 Antarctica: Ross sector, 1995, R. I. L. Smith 10196 (AAS) EU360750Xm19 Antarctica: Ross sector, 1995, R. I. L. Smith 9825 (AAS) EU360751Xm20 Antarctica: Enderby sector, 1997, A. D. Kennedy 43 (AAS) EU360756Xm21 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC7 (TSB) EU360757Xm22 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC2 (on bryophytes)(TSB) EU360758Xm23 Antarctica: Victoria Land, 2006, R. Bargagli et al. MC2 (on rock) (TSB) EU360767Xm24 Antarctica: Princess Elizabeth Land, 1999, P. Dyer (C) EU718625Xm25 Antarctica: Victoria Land, 2000, S. Pannewitz (C) EU718626Xm26 Antarctica: Dronning Maud Land, 2002, P. Johansson (hb. PJ) EU378917Xanthoria candelariaXc1 Iceland: S-Mulasysla, 1997, U. Søchting US 7488 (C) AY081154Xc2 Antarctica: voucher 169 (S. Scherrer & R. Honegger) AJ320138
2008 Xanthomendoza borealis and Xanthoria mawsonii—Lindblom & Søchting 401
whereas the two other common haplotypes[five (h3) and nine (h2) individuals, respect-ively] were represented by thalli bothlabelled X. borealis and X. mawsonii.
Discussion
Molecular phylogenetic analyses
Statistical parsimony implemented ashaplotype networks as a method for inferringrelationships between closely related speciesand analysing intraspecific data sets is in-creasingly used in a wide variety of groupsof organism, for example, bats (Weyandt& Van Den Bussche 2007), molluscs(Jarnegren et al. 2007), and higher plants(Banfer et al. 2006) (see also Hart & Sunday2007). In recent years, this method ofanalysis has been successfully applied tomolecular data from lichen-forming fungi(e.g. Printzen & Ekman 2002; Lindblom& Ekman 2005, 2006, 2007; R. ReeseNæsborg unpublished) and it has proven toshow efficiently patterns of genetic variationand reveal discontinuities between relatedspecies.
In this study, comprising molecular ITSsequences from 40 thalli collected over mostof the distribution range of X. borealis/mawsonii, ten haplotypes were found. Thereare few investigations of genetic variation atspecific level in lichen-forming fungi forcomparison. However, the amount ofwithin-species (infraspecific) genetic vari-
ation that we found in X. borealis/mawsonii,is at the same level as the genetic variabilityobserved in Cavernularia hultenii (Printzen& Ekman 2002) and Xanthoria parietina(Lindblom & Ekman 2005) over approxi-mately the same geographical range. In ad-dition, it seems that the reproductive mode,that is producing mainly sexual diaspores(ascospores) or producing mainly vegetativediaspores (e.g., soredia or isidia), is notcorrelated with the genetic variability.
Secondary chemistry
All specimens screened for secondarychemistry proved to belong to chemosyn-drome A of Teloschistaceae (sensu Søchting1997). Chemosyndrome A3 is the morecommon chemosyndrome found in thegenus Xanthomendoza, but some taxa withchemosyndrome A have previously beenreported (Søchting et al. 2002).
Morphology and anatomy
We did not observe any apothecia in thematerial labelled X. borealis and X. mawsonii.Apothecia have previously been reportedonly twice (Poelt & Petutschnig 1992a;Øvstedal & Lewis Smith 2001), howeverboth reports are doubtful or erroneous. Poelt& Petutschnig (1992a) recorded that theyobserved one apothecium on X. borealis, butdid not indicate the collection. Øvstedal &Lewis Smith (2001) cite one collection of
F. 1. Final haplotype network constructed from ITS sequences of specimens of Xanthomendoza borealis andXanthoria mawsonii used in this study. Sizes of haplotype circles indicate frequency of the haplotypes in the totalsample. Small empty circles represent haplotypes not present in the sample. Lines between haplotypes each
represent one mutational step.
402 THE LICHENOLOGIST Vol. 40
X. mawsonii (RILS 9694, hb. AAS) withapothecia. We examined the collection citedand the apothecia proved not to belongto X. mawsonii, but to intermixed lobes ofXanthoria elegans.
Mature pycnidia with conidia were rare inthe material studied, comprising c. 115specimens. Poelt & Petutschnig (1992a)noted that conidia (‘‘spermatien’’) in X.borealis were rarely fully developed, butmeasure 3·7–3·9�1–1·1 �m. Castello(1995), on the other hand, found thatmature pycnidia with conidia (‘‘spermatia’’)were present in several specimens of X. maw-sonii; conidia measured 3–4·5�0·8–1·2 �m.Lindblom (1997) reported the conidia ofX. borealis to be 3·8–4·7�c. 1·5 �m.
The morphological, anatomical and mol-ecular studies presented above strongly indi-cate that X. mawsonii and X. borealis shouldbe treated as one species: Xanthomendozaborealis (R. Sant. & Poelt) Søchting,Karnefelt & S. Kondratyuk.
Material of X. borealis and, in particular,X. mawsonii have often been regarded asvery difficult to separate from Xanthoria can-delaria. The growth form and habitat selec-tion are fairly similar and, in addition, bothspecies occur in the same geographical areas.Xanthoria candelaria is a very common and
widely distributed taxon, which is morpho-logically variable and a world-wide taxo-nomic revision is necessary. Xanthomendozaborealis in the sense of our study has a morerestricted ecology and distribution. Usefulcharacters for separating the two species arelisted in Table 2. Experience of the species,the diagnostic characters, and morphologi-cal plasticity are still required in order todetermine material correctly.
Taxonomy
Most authors dealing with Xanthoria maw-sonii have not expressed doubts on its taxo-nomic status. Many have, however, haddifficulties distinguishing it from X. cande-laria. Castello (1995) wrote: ‘‘The type ma-terial of X. mawsonii itself is an intermediateform, and is not much representative of thespecies.’’ The morphology of the holotypecollection corresponds well with that ofX. candelaria collected from South ShetlandIslands and the subantarctic islands. Unfor-tunately it lacks pycnidia, so that this diag-nostic character is not available (see Table2). Based on our extensive studies ofmaterial from the Antarctic region we arecertain that the holotype of X. mawsonii(Fig. 2) belongs to X. candelaria. Xanthoria
T 2. Useful characters for separating Xanthomendoza borealis and Xanthoria candelaria. Measurements are givenas (min. value obs.–) arithmetic mean obs. (–max. value obs.) (rounded to nearest integer)
Xanthomendoza borealis Xanthoria candelaria
Upper surface, colour orange-reddish yellow-orangeUpper surface, texture �pruina or crystals* smoothLobes narrow-wide narrow, richly branchedLobes, shape dorsiventral dorsiventral to subtereteLobes, tips revolute straightThickness, total thallus (99–)123(–186) �m (81–)105(–144) �mThickness, upper cortex (24–)29(–32) �m (11–)22(–35) �mThickness, lower cortex (24–)29(–37) �m (16–)22(–28) �mApothecia not known rareConidia, shape bacilliform ellipsoidSoralia blastidia; �labriform blastidious outgrowthsChemosyndrome† A‡ AEcology, major substratum rock, bryophytes rock, bark, lignum
*Similar to Xanthoria aureola (Lindblom & Ekman 2005).†In the sense of Søchting (1997).‡But see Lindblom (1997).
2008 Xanthomendoza borealis and Xanthoria mawsonii—Lindblom & Søchting 403
mawsonii C. W. Dodge [B. A. N. Z. Antarct.Res. Exped. 1929–1931 Repts., ser. B, VII:236 (1948); type: Antarctica, George VLand, Cape Denison, 67(S, 142(36#E,winter quarters. A. A. E. 38, leg. Mawson,1929–31 (FH!—holotype)] is thus a syno-nym of Xanthoria candelaria. See also no-menclature in Castello (1995). Hence, theonly name available for this taxon, which isdistinct from X. candelaria, is Xanthomen-doza borealis (R. Sant. & Poelt) Søchting,Karnefelt & S. Kondratyuk.
Mitt. Inst. Allg. Bot. Hamburg 30–32: 237 (2002).—Xanthoria borealis R. Santesson & Poelt, Nova Hedwigia54: 15 (1992); type: Sweden, Torne Lappmark,Tornetrask, the island of Abisko-suolo off Abisko,1943, R. Santesson 3481 (UPS—holotype!; GZU—isotype!).
Xanthoria mawsonii auct. non C. W. Dodge.
(Fig. 3)
Thallus saxicolous or muscicolous, foliose,mostly aggregated in small cushions, up to1·5 cm diam. Lobes flat or more oftenstrongly convex, up to 1 mm broad, horizon-tal to more often ascending or erect, oftenfastigiously fixed to the substratum by acentral hold-fast, with an incised to crenu-lated downward bent margin producing nar-row finger-like projections with an oftenmore yellowish tinge; colour orange with areddish tinge when exposed to bright light;sometimes with a thin pruina. Rhizinae veryfew. Soralia abundant, with blastidious sore-dia (sensu Poelt & Petutschnig 1992a),formed irregularly on the lower side of thelobe tips that can be lip-, helmet-, or cornet-shaped. Soredia c. 40 �m diam., sometimesfew and not liberated, sometimes abun-dantly produced and loose.
Apothecia not observed.Pycnidia very rare, immersed or slightly
protruding, same colour as the upper lobesurface. Conidia bacilliform, hyaline, 1·9–3·4�1–1·5 �m.
F. 2. Xanthoria mawsonii C. W. Dodge (FH—holotype). Scale=1 mm.
404 THE LICHENOLOGIST Vol. 40
F. 3. Xanthomendoza borealis, habitus. A, from Greenland; B. from Southern Victoria Land, Antarctica.Scale=1 mm.
2008 Xanthomendoza borealis and Xanthoria mawsonii—Lindblom & Søchting 405
For further descriptions of the species seePoelt & Petutschnig (1992a), Castello(1995), Lindblom (1997), and Øvstedal &Lewis Smith (2001).
Chemistry. All specimens screened havehigh concentrations of parietin and smallproportions of teloschistin, fallacinal, pari-etinic acid and emodin corresponding tochemosyndrome A (Søchting 1997).
Habitat and distribution. Xanthomendozaborealis grows on horizontal or vertical rocksthat are often somewhat enriched by e.g.guano (Poelt & Petutschnig 1992a, 1992b).In continental Antarctica it is very abundanton moss cushions together with Xanthoriacandelaria in sites that are eutrophicated bypenguin rookeries (Pannewitz et al. 2006, asX. mawsonii).
Distribution and biogeography. It is evidentthat Xanthomendoza borealis is a true bipolarlichen species (Fig. 4). In the NorthernHemisphere it is widespread in Arctic regionsand in the boreal zone extending southwardsto central Scandinavia in Europe (Santessonet al. 2004; Poelt & Petutschnig 1992b) andto British Columbia in North America(Lindblom 1997), but nowhere is it very
common. Poelt and Petutschnig (1992a)cited specimens from Oregon and Colorado.However, these belong to Xanthomendozamendozae (Rasanen) Karnefelt & S.Kondratyuk (Lindblom 1997). A recordfrom the Himalayas (Nepal), which wascited by Poelt & Petutschnig (1992a), alsobelongs to X. mendozae (Rasanen) S.Kondratyuk & Karnefelt (L. Lindblom,determination labels 1997 and 2008).
In the Southern Hemisphere X. borealis iswidespread and abundant in continentalAntarctica, wherever there are ice-freeareas (Pannewitz et al. 2006). It appearsto be absent from the maritime Antarctic(Fig. 4).
The genus Xanthomendoza has by far itslargest species diversity in North America,and only a limited number of species areknown from Australasia and South America.Hence, we assume that the occurrence inAntarctica of X. borealis may be the result oflong distance transport, presumably by birdsor by wind. Consequently, its rarity in mesicclimates in the Antarctic may reflect a pref-erence for a continental climate or simplythat its propagules by chance have not yetarrived in suitable microhabitats. The Andesin southern South America, however, havebeen insufficiently explored to conclude with
F. 4. World distribution of Xanthomendoza borealis. Based on specimens verified in this study.
406 THE LICHENOLOGIST Vol. 40
certainty that X. borealis is absent there. Onthe other hand its occurrence in Antarcticacould be the result of populations survivingthere after separation of the major landsurfaces of the Earth. Both hypotheses havebeen tested using lichen-forming fungi byPrintzen et al. (2003).
In order to elicit the origin of this bipolardistribution, the population dynamics of X.borealis should be examined, for example,migration patterns and population sizechanges, genetic variability on a populationlevel and/or on smaller geographical scales.The level of variation in the Northern andSouthern Hemispheres, respectively, shouldbe compared. Powerful modern statisticalmethods for analysis of molecular sequencese.g. nested clade analysis as used by e.g.Printzen et al. (2003) or other methods usinga Bayesian framework (e.g. Drummond et al.2002) could provide important clues. Forexample, the hypothesis that the occurrencein Antarctica of this exclusively asexuallyreproducing species is the result of long-range transport or alternative hypothesescould be tested. From this study, we haveindications of within-species and within-population variability on a world-wide aswell as on a small spatial scale, that could beuseful in further studies.
1992, Alstrup 921318 (C); Siorapaluh, 1993, Alstrup(C). W Greenland: Disko: Qutdligssat, 1950, Gelting13453c (C); Godhavn, Skarvfjeld, 1992, Andersen &Klamer 92124 (C); Nordfjord, Kugsinerssuaq, 1949,Gelting (C); Mellemfjord, Sarqardlit silardlit, 1950,Gelting (C); Godthabsfjord, Karra, 1976, Alstrup766318 (C); Mylius Erichsen Land, Campanuladal, Wof river, N of Campanula lake, 1995, Alstrup & Daniels3032 (C); Angujartorfiup nuna, Arnangarngup kua,1991, Alstrup 91972, 919814 (C); Kellervik N of har-bour, 1991, Alstrup 912114 (C); Søndre StrømfjordAirport, Ravneklippen, 1991, Alstrup (C). S Greenland:Narsaq community, Tugtutooq, Sildefjord, 2005,Alstrup (C); Narsarssuaq, 2005, Søchting 10450 (C). EGreenland: Kronprins Christian Land, Centrum Sø, S ofFossilfjeld, 1995, Alstrup & Daniels 1643 (C); Kangerd-lugssuak district, NE of airport, 1991, Alstrup 91150(C); Ravneklippe, 1991, Alstrup 91967 (C); KapHirschell, 1929, Lynge (C); Jacksonøye, 1929, Lynge(UPS); Mygbukta, 1929, Lynge (UPS).—Russia:Lopatka Peninsula, 1994, Mattsson 305, 312, 314(LD); New Sibirian Islands, Ostrov Faddeyevskiy,1994, Mattsson 276 (LD); Siberia, Wrangel Island,1994, Mattsson 3468 (UPS); Taimyr Peninsula,Byrranga Mts, 1994, Zhurbenko 94411 (UPS); NovajaSemlja, Pol Bay, 1921, Lynge (UPS); Novaja Semlja,Nordre Korsø, 1921, Lynge (UPS).—Canada: BritishColumbia: Buse Hill, 1994, Alstrup [IMC 5 lichen fieldtrip] (C).
Originally labelled X. mawsonii. Antarctica: Dron-ning Maud Land: Muhlig-Hofmanfjella, Hoggestabben,1985, Engelskjøn (BG); Gjelsviksfjella, Jutulsessen,1985, Engelskjøn (BG); Steinnabben, Heimefrontfjella,2002, Johansson (hb. Johansson, UPS). Enderby Land:Oy Gardens, Kemp Land, 1997, Kennedy 43 (AAS).Princess Elizabeth Land: Vestfold Hills, 1999, Dyer (C).Wilkes Land: SE of New Casey, Bailey Peninsula. BuddCoast, 1985, Smith 6280 (AAS); Shirley Island, BuddCoast, 1985, Smith 6268, 6308 (AAS); Whitney Point,Clark Peninsula, Budd Coast, 1985, Smith 6176, 6178(AAS). Victoria Land: Base of Cape Hallett, 1964,Rudolph 64006 (LD); Hallett Peninsula, Victory Mts.,Crater Cirque, 1996, Bersan A819/30432 (TSB); LadyNewnes Bay, Cape King, 1993–1994, Bargagli A542/21439 (TSB); Ross Sector, Edmonson Point, Northside of large lake (‘‘Penguin Lake’’), 1995, Smith 9694(AAS) [apothecia belong to intermixed X. elegans]; RossSector, Harrow Peaks, 1996, Smith 9859 (AAS); RossSector, Kay Island, 1994, Bargagli (Smith 9963)(AAS); Ross Sector, SW side of Cape Washington,1996, Smith 9825 (AAS); Ross Sector, SouthernDaniell Peninsula, Cape Phillips, 1996, Smith 10164(AAS); Ross Sector, Upper moraine of Tinker Glacier–Burns Glacier, 1995, Smith 9681 (AAS); Ross Sector,Wood Bay, Kay Island, 1995, Smith 10196, 10213,10223 (AAS); South-east end of Inexpressible Island,1995, Smith 9721 (AAS); Terra Nova Bay, Base BaiaTerra Nova, 1987–1988, del Frate A96/19257 (TSB);Wood Bay, Harrow Peaks, 1993–1994, Bargagli A507/21408 (TSB); Wood Bay, Mt. Melbourne, EdmonsonPoint, 1988, Modenesi A397/19261 (TSB); Zona ReliefInlet, Prior Island, 1990, Sedmak A273/19259 (TSB).
2008 Xanthomendoza borealis and Xanthoria mawsonii—Lindblom & Søchting 407
We thank M. Castello (Trieste), H. C. Gjerlaug(Hedmark), P. Johansson (O} stersund), B. Schroter(Kiel), P. S. Dyer (Nottingham), and the curatorsof public herbaria who provided material on loan.P. Froden (Lund) kindly shared one unpublishedsequence, now deposited in GenBank. We are gratefulto A. Løth (Copenhagen), who assisted with themolecular work, L. Christiansen (Copenhagen), whomade the HPLC analyses, and B. Helle (Bergen), whodrew Figure 1. Work in Copenhagen was supportedby a grant from the European Commission’s (FP6)Integrated Infrastructure Initiative programme SYN-THESYS (DK-TAF 3452) and the Carlsberg Founda-tion (ANS-1206/10).
R
Arup, U. (2006) A new taxonomy of the Caloplacacitrina group in the Nordic countries, except Ice-land. Lichenologist 38: 1–20.
Banfer, G., Moog, U., Fiala, B., Mohamed, M.,Weising, K. & Blattner, F. R. (2006) A chloroplastgenealogy of myrmecophytic Macaranga species(Euphorbiaceae) in Southeast Asia reveals hybridi-zation, vicariance and long-distance dispersals.Molecular Ecology 15: 4409–4424.
Castello, M. (1995) The lichen genus Xanthoria inAntarctica. Cryptogamie, Bryologie Lichénologie 16:79–87.
Clement, M., Posada, D. & Crandall, K. A. (2000)TCS: a computer program to estimate gene gene-alogies. Molecular Ecology 9: 1657–1659.
Dodge, C. W. (1948) Lichens and lichen parasites.British-Australian-New Zealand Antarctic ResearchExpedition 1929–1931 Reports, series B, Zoology-Botany 7: 1–276.
Dodge, C. W. (1973) Lichen Flora of the AntarcticContinent and Adjacent Islands. Canaan: PhoenixPublishing.
Drummond, A. J., Nicholls, G. K., Rodrigo, A. G. &Solomon, W. (2002) Estimating mutation par-
ameters, population history and genealogy simul-taneously from temporally spaced sequence data.Genetics 161: 1307–1320.
Gardes, M. & Bruns, T. D. (1993) ITS primers withenhanced specificity for basidiomycetes—application to the identification of mycorrhizae andrusts. Molecular Ecology 2: 113–118.
Hart, M. W. & Sunday, J. (2007) Things fall apart:biological species form unconnected parsimonynetworks. Biology Letters 3: 509–512.
Hertel, H. (1987) Bemerkenswerte Funde sudhemi-spharischer, saxicoler Arten der SammelgattungLecidea. Mitteilungen der Botanische StaatssammlungMünchen 23: 321–340.
Jarnegren, J., Schander, C., Sneli, J.-A., Rønningen, V.& Young, C. M. (2007) Four genes, morphologyand ecology: distinguishing a new species of Acesta(Mollusca; Bivalvia) from the Gulf of Mexico.Marine Biology 152: 43–55.
Lindblom, L. (1997) The genus Xanthoria (Fr.) Th. Fr.in North America. Journal of the Hattori BotanicalLaboratory 83: 75–172.
Lindblom, L. (2006) Xanthoria galericulata, a newsorediate lichen species, with notes on similarspecies in North America. Bryologist 109: 1–8.
Lindblom, L. & Ekman, S. (2005) Molecular evidencesupports the distinction between Xanthoria pari-etina and X. aureola (Teloschistaceae, lichenizedAscomycota). Mycological Research 109: 187–199.
Lindblom, L. & Ekman, S. (2006) Genetic variationand population differentiation in Xanthoria pari-etina on the island Storfosna, central Norway.Molecular Ecology 15: 1545–1559.
Lindblom, L. & Ekman, S. (2007) New evidencecorroborates population differentiation in Xantho-ria parietina. Lichenologist 39: 259–271.
Øvstedal, D. O. & Lewis Smith, R. I. (2001) Lichens ofAntarctica and South Georgia: a Guide to TheirIdentification and Ecology. Cambridge: CambridgeUniversity Press.
Pannewitz, S., Green, T. G. A., Schlensog, M.,Seppelt, R., Sancho, L. G. & Schroeter, B. (2006)Photosynthetic performance of Xanthoria mawsoniiC. W. Dodge in coastal habitats, Ross Sea region,continental Antarctica. Lichenologist 38: 67–81.
Poelt, J. & Petutschnig, W. (1992a) Beitrage zurKenntnis der Flechtenflora des Himalaya IV. DieGattungen Xanthoria und Teloschistes zugleichVersuch einer Revision der Xanthoria candelaria-Gruppe. Nova Hedwigia 54: 1–36.
Poelt, J. & Petutschnig, W. (1992b) Xanthoria cande-laria und ahnliche Arten in Europa. Herzogia 9:103–114.
Printzen, C. & Ekman, S. (2002) Genetic variabilityand its geographical distribution in the widelydisjunct Cavernularia hultenii. Lichenologist 34:101–111.
Printzen, C., Ekman, S. & Tønsberg, T. (2003) Phylo-geography of Cavernularia hultenii: evidence of slowgenetic drift in a widely disjunct lichen. MolecularEcology 12: 1473–1486.
408 THE LICHENOLOGIST Vol. 40
Santesson, R., Moberg, R., Nordin, A., Tønsberg, T. &Vitikainen, O. (2004) Lichen-forming and Licheni-colous Fungi of Fennoscandia. Uppsala: UppsalaUniversity, Museum of Evolution.
Søchting, U. (1997) Two major anthraquinone chemo-syndromes in Teloschistaceae. Bibliotheca Licheno-logica 68: 135–144.
Søchting, U. & Olech, M. (1995) The lichen genusCaloplaca in Polar regions. Lichenologist 27:463–471.
Søchting, U., Karnefelt, I. & Kondratyuk, S. Y. (2002)Revision of Xanthomendoza (Teloschistaceae,Lecanorales) based on morphology, anatomy, sec-ondary metabolites and molecular data. Mitteilun-gen aus dem Institut für Allgemeine Botanik, Hamburg30: 225–240.
Søchting, U., Øvstedal, D. O. & Sancho, L. G. (2004)The lichens of Hurd Peninsula, Livingston Island,South Shetlands, Antarctica. In Contributions toLichenology (P. Dobbeler, ed): 607–658. Berlin,Stuttgart: Gebruder Borntraeger.
Stenroos, S. (1993) Taxonomy and distribution of thelichen family Cladoniaceae in the Antarctic and
Templeton, A. R., Crandall, K. A. & Sing, C. F. (1992)A cladistic analysis of phenotypic associations withhaplotypes inferred from restriction endonucleasemapping and DNA sequence data. III. Cladogramestimation. Genetics 132: 619–633.
Thompson, J. D., Gibson, T. J., Plewniak, F.,Jeanmougin, F. & Higgins, D. G. (1997) TheClustalX windows interface: flexible strategiesfor multiple sequence alignment aided by qualityanalysis tools. Nucleic Acids Research 24:4876–4882.
Weyandt, S. E. & van Den Bussche, R. A. (2007)Phylogeographic structuring and volant mammals:the case of the pallid bat (Antrozous pallidus).Journal of Biogeography 34: 1233–1245.
White, T. J., Bruns, T., Lee, S. & Taylor, J. (1990)Amplification and direct sequencing of fungalribosomal RNA genes for phylogenetics. In PCRProtocols: A Guide to Methods and Applications(M. A. Innis, D. H. Gelfand, J. J. Sninsky & T. J.White, eds): 315–322. San Diego: Academic Press.
Accepted for publication 25 May 2008
2008 Xanthomendoza borealis and Xanthoria mawsonii—Lindblom & Søchting 409
