Arthrorhaphis

{{Short description|Genus of fungi}} {{Use dmy dates|date=July 2025}} {{Use Oxford spelling|date=July 2025}} {{Automatic taxobox | image = Arthrorhaphis alpina 1543680788.jpg | image_caption = ''Arthrorhaphis alpina'' | taxon = Arthrorhaphis | authority = Th.Fr. (1860) | parent_authority = Poelt & Hafellner (1976) | type_species = ''Arthrorhaphis flavovirescens'' | type_species_authority = (A.Massal.) Th.Fr. (1861) | synonyms_ref = <ref name="Species Fungorum synonymy"/> | synonyms = *''Gongylia'' {{au|Körb. (1855)}} *''Mycobacidia'' {{au|Rehm (1890)}} *''Parathalle'' {{au|Clem. (1909)}} *''Raphiospora'' {{au|A.Massal. (1853)}} | subdivision_ranks = | subdivisions = }}

'''''Arthrorhaphis''''' is a genus of fungi in the monotypic family '''Arthrorhaphidaceae'''. It has 13 species.<ref name="Wijayawardene et al. 2020"/> Species in this family have a widespread distribution in temperate and montane habitats. They grow symbiotically with green algae, or parasitically on other lichens.<ref>{{cite book |vauthors=Cannon PF, Kirk PM |title=Fungal Families of the World |publisher=CAB International |location=Wallingford, UK |year=2007 |page=20 |isbn=978-0-85199-827-5}}</ref> These fungi typically start as parasites on other lichens but can later become free-living, forming bright greenish-yellow to greyish scales on acidic soils and weathered rocks in cool upland regions.

==Taxonomy==

The genus was circumscribed by Theodor Magnus Fries in 1860. The family was proposed by lichenologists Josef Poelt and Josef Hafellner in 1976.<ref name="Poelt & Hafellner 1976"/> The family Arthrorhaphidaceae has an uncertain taxonomic placement in the class Lecanoromycetes; that is, it is incertae sedis with respect to ordinal placement.<ref name="Wijayawardene et al. 2020"/>

==Description==

''Arthrorhaphis'' species either have no thallus of their own or form a thin crust that lacks a distinct marginal zone. When the fungus grows independently it soon breaks into tiny, strongly convex scales ({{lichengloss|squamules}}) that are bright greenish yellow to whitish grey; these scales have no true protective {{lichengloss|cortex}}, only a delicate colourless surface layer. Some taxa also produce fine, powdery soredia that serve as propagules for vegetative reproduction. The {{lichengloss|photobiont}} partner is a {{lichengloss|chlorococcoid}} green alga that forms a conspicuous, compact {{lichengloss|algal layer|layer}} of cells.<ref name="Cannon et al. 2025"/>

The sexual fruiting bodies (apothecia) sit directly on the thallus or nestle between the squamules. They are black and either urn-shaped ({{lichengloss|urceolate}}) or {{lichengloss|disc}}-like, and many are packed with crumbly, brown-green {{lichengloss|granules}} that resemble droplets. The surrounding wall ({{lichengloss|exciple}}) is poorly developed, consisting of loosely woven hyphae with markedly swollen walls. Threads called paraphyses weave through the spore-bearing layer (hymenium); they are slender, freely branched and interconnected, with only slight thickening at their tips. Oil droplets are often scattered throughout the hymenium.<ref name="Cannon et al. 2025"/>

Each ascus contains eight ascospores and is club-shaped ({{lichengloss|clavate}}); the apex shows only minimal thickening and reacts negatively to iodine (K/I–) but does have a small transparent {{lichengloss|ocular chamber}}. The spores are long and narrow—ranging from cylindrical to nearly needle-like—and are divided by three to fifteen, occasionally up to twenty-eight, internal cross-walls (septa). Asexual reproduction occurs in conspicuous black pycnidia that produce smooth, colourless, ellipsoidal conidia. Chemically, the genus is known to contain rhizocarpic acid, epanorin and various unidentified pigments, alongside secondary metabolites derived from its host lichens.<ref name="Cannon et al. 2025"/>

==Ecology==

''Arthrorhaphis'' species favour acidic substrates and, less often, mildly calcareous ones. They usually start out parasitising crustose or fruticose lichens but may later become free-living, spreading across soil among mosses or over weather-worn rock in cool, often upland regions.<ref name="Cannon et al. 2025"/>

==Species== thumb|right|''Arthrorhaphis citrinella'' *''Arthrorhaphis aeruginosa'' {{au|R.Sant. & Tønsberg (1994)}}<ref name="Santesson & Tønsberg 1994"/> *''Arthrorhaphis alpina'' {{au|(Schaer.) R.Sant. (1980)}}<ref name="Hawksworth et al. 1980"/> *''Arthrorhaphis anziana'' {{au|(Lynge) Poelt (1969)}} *''Arthrorhaphis arctoparmeliae'' {{au|Kocourk. & van den Boom (2005)}}<ref name="Kocourková & van den Boom 2005"/> *''Arthrorhaphis citrinella'' {{au|(Ach.) Poelt (1969)}} *''Arthrorhaphis grisea'' {{au|Th.Fr. (1861)}} *''Arthrorhaphis muddii'' {{au|Obermayer (1994)}}<ref name="Obermayer 1994"/> *''Arthrorhaphis olivaceae'' {{au|R.Sant. & Tønsberg (1994)}}<ref name="Santesson & Tønsberg 1994"/> *''Arthrorhaphis phyllobaeis'' {{au|Etayo & Palice (2017)}}<ref name="Etayo 2017"/> *''Arthrorhaphis summorum'' {{au|B.de Lesd. (1933)}} *''Arthrorhaphis vacillans'' {{au|Th.Fr. & Almq. ex Th.Fr. (1867)}}<ref name="Fries 1867"/> *''Arthrorhaphis viridescens'' {{au|Rabenh. (1870)}}

==References== {{Reflist|colwidth=30em|refs=

<ref name="Cannon et al. 2025">{{cite book |last1=Cannon |first1=P. |last2=Coppins |first2=B. |last3=Aptroot |first3=A. |last4=Sanderson |first4=N. |last5=Simkin |first5=J. |year=2025 |title=Miscellaneous lichens and lichenicolous fungi, including ''Aphanopsis'' and ''Steinia'' (Aphanopsidaceae), ''Arthrorhaphis'' (Arthrorhaphidaceae), ''Buelliella'', ''Hemigrapha'', ''Melaspileella'', ''Stictographa'' and ''Taeniolella'' (Asterinales, family unassigned), ''Phylloblastia'' (Chaetothyriales, family unassigned) ''Cystocoleus'' (Cystocoleaceae), ''Sclerococcum'' (Dactylosporaceae), ''Eiglera'' (Eigleraceae), ''Epigloea'' (Epigloeaceae), ''Euopsis'' (Harpidiaceae), ''Lichenothelia'' (Lichenotheliaceae), ''Lichinodium'' (Lichinodiaceae), ''Melaspilea'' (Melaspileaceae), ''Epithamnolia'' and ''Mniaecia'' (Mniaeciaceae), ''Lichenostigma'' (Phaeococcomycetaceae), ''Pycnora'' (Pycnoraceae), ''Racodium'' (Racodiaceae), ''Chicitaea'' and ''Loxospora'' (Sarrameanaceae), ''Schaereria'' (Schaereriaceae), ''Strangospora'' (Strangosporaceae), ''Botryolepraria'' and ''Stigmidium'' (Verrucariales, family unassigned), and ''Biatoridium'', ''Mycoglaena'', ''Orphniospora'', ''Piccolia'', ''Psammina'' and ''Wadeana'' (order and family unassigned) |series=Revisions of British and Irish Lichens |volume=57 |page=51 |url=https://britishlichensociety.org.uk/sites/default/files/Miscellaneous%20genera_0.pdf}}{{Open access}}</ref>

<ref name="Etayo 2017">{{cite book |last1=Etayo |first1=Javier |year=2017 |title=Hongos liquenícolas de Ecuador |trans-title=Lichenicolous fungi of Ecuador |series=Opera Lilloana |publisher=Fundación Miguel Lillo |location=Tucumán |volume=50 |page=98 |language=es}}</ref>

<ref name="Fries 1867">{{cite journal |last=Fries |first=T.M. |year=1867 |title=Nya skandinaviska laf-arter |trans-title=New Scandinavian lichen species |journal=Botaniska Notiser |volume=1867 |pages=105–110}}</ref>

<ref name="Hawksworth et al. 1980">{{cite journal |last1=Hawksworth |first1=D.L. |last2=James |first2=P.W. |last3=Coppins |first3=B.J. |title=Checklist of British lichen-forming, lichenicolous and allied fungi |journal=The Lichenologist |volume=12 |issue=1 |year=1980 |doi=10.1017/s0024282980000035 |pages=1–115 [106] |bibcode=1980ThLic..12....1H }}</ref>

<ref name="Kocourková & van den Boom 2005">{{cite journal |last1=Kocourková |first1=J. |last2=van den Boom |first2=P.P.G. |year=2005 |title=Lichenicolous fungi from the Czech Republic II. ''Arthrorhaphis arctoparmeliae'' sp. nov. and some new records for the country |journal=Herzogia |volume=18 |pages=23–35}}</ref>

<ref name="Obermayer 1994">{{cite journal |last1=Obermayer |first1=W. |year=1994 |title=Die Flechtengattung ''Arthrorhaphis'' (Arthrorhaphidaceae, Ascomycotina) in Europa und Grönland |journal=Nova Hedwigia |volume=58 |issue=3–4 |pages=275–333 |language=de}}</ref>

<ref name="Poelt & Hafellner 1976">{{cite journal |last1=Poelt |first1=J. |last2=Hafellner |first2=J. |year=1976 |title=Lichen Neonorrlinia-Trypetheliza and family Arthrorhaphidaceae |journal=Phyton: Annales Rei Botanicae |volume=17 |issue=3–4 |pages=213–220 |language=de}}</ref>

<ref name="Santesson & Tønsberg 1994">{{cite journal |last1=Santesson |first1=R. |last2=Tønsberg |first2=T. |year=1994 |title=''Arthrorhaphis aeruginosa'' and ''A. olivacea'', two new lichenicolous fungi |journal=The Lichenologist |volume=26 |issue=3 |pages=295–299 |doi=10.1006/lich.1994.1021 |bibcode=1994ThLic..26..295S }}</ref>

<ref name="Species Fungorum synonymy">{{cite web |title=Synonymy: ''Arthrorhaphis'' Th. Fr., Lich. arct. (Uppsala): 203 (1860) |url=http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=336 |publisher=Species Fungorum |access-date=20 March 2020}}</ref>

<ref name="Wijayawardene et al. 2020">{{cite journal |display-authors=6 |last1=Wijayawardene |first1=Nalin |last2=Hyde |first2=Kevin |first3=Laith Khalil Tawfeeq |last3=Al-Ani |last4=Somayeh |first4=Dolatabadi |last5=Stadler |first5=Marc |last6=Haelewaters |first6=Danny |last7=Tsurykau |first7=Andrei |last8=Mesic |first8=Armin |last9=Navathe |first9=Sudhir |last10=Papp |first10=Viktor |last11=Oliveira Fiuza |first11=Patrícia |last12=Vázquez |first12=Víctor |last13=Gautam |first13=Ajay |last14=Becerra |first14=Alejandra G. |last15=Ekanayaka |first15=Anusha |last16=K. C. |first16=Rajeshkumar |last17=Bezerra |first17=Jadson |last18=Matočec |first18=Neven |last19=Maharachchikumbura |first19=Sajeewa |last20=Suetrong |first20=Satinee |year=2020 |title=Outline of Fungi and fungus-like taxa |journal=Mycosphere |volume=11 |pages=1060–1456 |doi=10.5943/mycosphere/11/1/8 |doi-access=free|hdl=11336/151990 |hdl-access=free }}</ref>

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Category:Lecanoromycetes Category:Lichen genera Category:Lecanoromycetes genera Category:Taxa described in 1860 Category:Taxa named by Theodor Magnus Fries