The genus was circumscribed in 2016 by lichenologists André Aptroot, Matthew Nelson, and Robert Lücking, with Dictyomeridium proponens assigned as the type species. The seven species they included in the genus were mostly previously classified in the genus Polymeridium, while the type species was known by different names in the genus Campylothelium. Phylogenetic analysis showed that the group of species was distant from the core group of their previous genus. An eight species, from Australia, was added to the genus in 2022.

Description

Dictyomeridium is distinguished from other genera in the family Trypetheliaceae by its {{lichengloss|muriform}} (multichambered) ascospores, the lateral ostioles of its ascomata, and several subtle microscopic differences in the form of the {{lichengloss|hamathecium}} and the ascospores. Dictyomeridium species are distinguished from each other by their reaction to the {{lichengloss|UV test}}, the dimensions of their spores, and by the presence or absence of a red pigment in their ostioles. All species lack a {{lichengloss|cortex}}, and have conical to {{lichengloss|pyriform}} ascomata with eccentric (i.e., not placed centrally) ostioles. Sometimes, {{lichengloss|pycnidia}} are present.

Species

Dictyomeridium amylosporum {{au|(Vain.) Aptroot, M.P.Nelsen & Lücking (2016)}} – pantropical
Dictyomeridium campylothelioides {{au|(Aptroot & Sipman) Aptroot, M.P.Nelsen & Lücking (2016)}} – Asia
Dictyomeridium immersum {{au|(Aptroot, A.A.Menezes & M.Cáceres) Aptroot, M.P.Nelsen & Lücking (2016)}} – Brazil
Dictyomeridium isohypocrellinum {{au|(Xavier-Leite, M.Cáceres & Aptroot) Aptroot, M.P.Nelsen & Lücking (2016)}} – Brazil
Dictyomeridium lueckingii {{au|Flakus & Aptroot (2016)}} – Bolivia
Dictyomeridium neureuterae {{au|A.J.Marshall, Aptroot, de Lange et Blanchon (2024)}} – New Zealand
Dictyomeridium paraproponens {{au|(Aptroot, M.Cáceres & E.L.Lima) Aptroot, M.P.Nelsen & Lücking (2016)}} – Brazil
Dictyomeridium proponens {{au|(Nyl.) Aptroot, M.P.Nelsen & Lücking (2016)}} – pantropical
Dictyomeridium tasmanicum {{au|P.M.McCarthy & Kantvilas (2022)}} – Tasmania, Australia

References

{{Reflist|refs=

{{cite journal |last1=Flakus |first1=Adam |last2=Kukwa |first2=Martin |last3=Aptroot |first3=André |title=Trypetheliaceae of Bolivia: an updated checklist with descriptions of twenty-four new species |journal=The Lichenologist |volume=48 |issue=6 |year=2016 |doi=10.1017/s0024282915000559 |pages=661–692|s2cid=89161746 |doi-access=free }}

{{cite journal |display-authors=6 |last1=Lücking |first1=Robert |last2=Nelsen |first2=Matthew P. |last3=Aptroot |first3=André |last4=Barillas de Klee |first4=Roselvira |last5=Bawingan |first5=Paulina A. |last6=Benatti |first6=Michel N. |last7=Binh |first7=Nguyen Quoc |last8=Bungartz |first8=Frank |last9=Cáceres |first9=Marcela E. S. |last10=Canêz |first10=Luciana da Silva |last11=Chaves |first11=José-Luis |last12=ERTZ |first12=Damien |last13=Esquivel |first13=Rhina Esmeralda |last14=Ferraro |first14=Lidia Itati |last15=Grijalva |first15=Alfredo |last16=Gueidan |first16=Cécile |last17=Hernández M. |first17=Jesús E. |last18=Knight |first18=Allison |last19=Lumbsch |first19=H. Thorsten |last20=Marcelli |first20=Marcelo P. |last21=Mercado-Díaz |first21=Joel A. |last22=Moncada |first22=Bibiana |last23=Morales |first23=Eduardo A. |last24=Naksuwankul |first24=Khwanruan |last25=Orozco |first25=Thelma |last26=Parnmen |first26=Sittiporn |last27=Rivas Plata |first27=Eimy |last28=Salazar-Allen |first28=Noris |last29=Spielmann |first29=Adriano A. |last30=Ventura |first30=Nohemy |title=A phylogenetic framework for reassessing generic concepts and species delimitation in the lichenized family Trypetheliaceae (Ascomycota: Dothideomycetes) |journal=The Lichenologist |volume=48 |issue=6 |year=2016 |doi=10.1017/s0024282916000505 |pages=739–762 |s2cid=135438593 |url=https://www.researchgate.net/publication/311503686|doi-access=free }}

{{cite journal |last1=Marshall |first1=Andrew J. |last2=Aptroot |first2=André |last3=Blanchon |first3=Dan J. |last4=de Lange |first4=Peter J. |title=A new species of Dictyomeridium (Trypetheliaceae) from Aotearoa / New Zealand and an updated key to species of the genus |journal=Perspectives in Biodiversity |volume=2 |issue=1 |year=2024 |doi=10.34074/pibdiv.002108 |pages=69–76}}

{{cite journal |last1=McCarthy |first1=P.M. |last2=Kantvilas |first2=G. |year=2022 |title=A new species of Dictyomeridium (lichenized Ascomycota, Trypetheliaceae) from Tasmania |journal=Australasian Lichenology |volume=90 |pages=10–13}}

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Category:Trypetheliaceae

Category:Dothideomycetes genera

Category:Lichen genera

Category:Taxa described in 2016

Category:Taxa named by André Aptroot

Category:Taxa named by Robert Lücking