Quantitative morphological data on Ramomarthamyces octomerus fungi (Ascomycota)

Ramomarthamyces octomerus sp. nov. is described here. This apothecial fungus is described from specimens collected in Mediterranean climate regions in southern Portugal, Spain (Canary Islands), and the Dalmatian region of Croatia. Presumably saprobic, R. octomerus occurs on intact, decorticated wood of Laurus novocanariensis and Olea europaea. Ascospores are cylindric-ellipsoid and seven-septate. Surprisingly, in our four-locus phylogenetic analysis (nuSSU, ITS1-5.8S-ITS2, LSU, mtSSU), this fungus clusters among species of Cyclaneusma, Marthamyces, Naemacyclus, and Ramomarthamyces in a core Marthamycetaceae clade that circumscribes primarily leaf-inhabiting, filiform-spored species. In addition, the asci of R. octomerus possess an amyloid pore, but the reaction varies between specimens collected in the Canary Islands and those collected in Portugal and Croatia. The occurrence of an amyloid reaction in the asci of R. octomerus challenges the characterization of Marthamycetales taxa as po..., Macromorphological observations of apothecia were made using an Olympus SZX9 or a Motic SMZ-168 stereomicroscope. Photomicrographs were made using transmitted light microscopy with an Olympus BX51 compound light microscope with 40×, 100×/1.30 oil immersion plan-achromatic objectives, together with an Olympus XC50 5.0-megapixel digital camera and Olympus cellSens Standard 1.14 image processing software.
To study the structure of apothecia and tissue types following [28: pp. 32–34], longitudinal sections through the midpoint of an apothecium were made by hand-sectioning with the aid of a stereomicroscope or by using a freezing stage mounted to a sliding microtome. Hand sections were made to observe living cells and tissues. The freezing microtome apparatus facilitated making sections that were uniform and thin (~15–25 µm). To make these, pieces of substratum supporting an apothecium were hydrated, soaked in a solution of dilute gum Arabic, and oriented on an electric, water-cooled, freezi..., , # Quantitative morphological data on *Ramomarthamyces octomerus* fungi (Ascomycota)

[https://doi.org/10.5061/dryad.83bk3jb0z](https://doi.org/10.5061/dryad.83bk3jb0z)

## Description of the data and file structure

Quantitative data includes ascospore length/width measurements from living and dead ascospores, as well as apothecium, paraphyses, ascus, and other micromorphological features. The data was obtained from the holotype and paratype specimens of *Ramomarthamyces octomerus* (Ascomycota, Leotiomycetes, Marthamycetales, Marthamycetaceae) (ILLS00122394: HOLOTYPE. ILLS00122395: PARATYPE).

Potential uses might include a comparison of ascospore morphology in the living vs dead states.

There are four files. The \"Data_Ramomarthamyces octomerus_all measurements except ascospores\" file contains morphological data of apothecia except ascospore measurements, the \"Data_Ramomarthamyces_octomerus_ascospore_measurements_dead\" are measurements from dead ascospores only, and \"Data_Ramomarthamyc...