Marcelleina evangelinae — a violet cup from Sonora

Marcelleina evangelinae is a small ascomycete described in 2026 from the temperate forests of the Sierra Madre Occidental in Mexico. The holotype was collected on 18 September 2021 near Los Pilares in the municipality of Yécora, at an altitude of about 1,297 metres. The fruiting bodies were five to nine millimetres across, cup-shaped at first and later flatter, and dark violet to almost black.

Colour alone was not enough to establish a species. The authors examined the structure of the layers of the fruiting body, the asci, the paraphyses and the ornamentation of the spores under a scanning electron microscope. The globose ascospores measured about 9–11 micrometres and had a dense, connected reticulum. The combination of characters distinguished the material from Marcelleina persoonii, among others. Phylogenetic analyses indicated a distinct lineage, and histochemical reactions helped to characterise the violet pigments containing phenolic groups.

The specific name honours Dr Evangelina Pérez-Silva, a pioneer of research on Mexican ascomycetes. The formal authorship reads Raymundo, Sánchez-Flores, Alv.-Cortés & Esqueda. The name was registered in MycoBank under the number MB 859789, and the diagnosis, type, figures and molecular data were published in MycoKeys under DOI 10.3897/mycokeys.136.195741.

The known habitat is mixed montane forest, and the fruiting bodies grew on substrate associated with decaying matter. One type and a limited number of collections do not allow the full range, abundance or threat status to be assessed. "New to science" does not mean the organism arose recently; it means that evidence meeting the rules of formal description has only now been gathered.

The discovery shows the value of documenting small cup fungi, which are easily passed over beside large cap fungi. A photograph preserves fresh colour, but identification requires spores, tissues, a type and sequences. This profile gives no information on edibility, because a taxonomic publication is not a food safety study.

The verifiability of a name rests on several connected elements. The MycoBank number leads to the nomenclatural record, the DOI to the publication, and the designation of a holotype to specific reference material. A sequence helps in comparing later collections but does not replace morphology and context. If future data changes the position of the genus, the name may receive a new combination; the type specimen will still remain the point of reference for what was originally described. Every subsequent record should state the method of identification and where the material is deposited.

What the paper establishes

The Marcelleina evangelinae holotype (ENCB) was collected on 18 September 2021 at Los Pilares near Yécora, Sonora, at 1,297 m. Cup-like apothecia measured 5–9 mm. Wider paraphyses, shorter asci and a dense, complete reticulum on globose ascospores separate it from M. persoonii. Anatomy, scanning-electron microscopy, histochemical reactions and multilocus phylogeny were combined; MycoBank: MB 859789. Collections indicate growth on decayed wood beneath Cupressus, unusual for a more often terrestrial genus, but a few records cannot establish an obligatory substrate. Staining supports phenolic groups in the violet pigment; the study neither identified the molecule nor demonstrated a medicinal effect. “Known only from Mexico” describes the current record set, not demonstrated endemism.