Modelling the cortex and hypothesis for the “head” of Suppiluliumaella schlagintweitii n.sp.

We describe two new species of green algae in Dasycladales from the Lower Cretaceous of the Eastern Carpathians (Romania), Suppiluliumaella schlagintweitii n. sp. and Triploporella loducai n. sp. The two new taxa display a mineralization coating most of the thallus, possibly casting light on their growth pattern. Suppiluliumaella schlagintweitii displays a differentiated, club-shaped thallus with a very elongated vegetative part below the fertile zone (“head”) and a corticated external layer, suggesting a Neomeris type of growth. We further describe a possible mineralized juvenile growth stage. Triploporella loducai is characterized by a rather short cylindrical thallus with a reduced vegetative region (sharp tapering rounded lower end), seemingly following a growth type resembling that of spherical Bornetella., The measurements related to the “head” of Suppiluliumaella schlagintweitii has been made on enlarged photos at 40x of specimens PSM RT37 and DiSTAR-BA.4283.2.
Biometric measurements were processed by Excel.
A procedure to evaluate the arrangement of cortical laterals is here proposed taking cortical parameters from the thin section.
Distance between the axes of two adjacent primary laterals at the cortex (dp) was computed as
dp = pDcx / w.
The area (Amesh) of a single hexagonal mesh of the “head” was computed as
Amesh= P*a/2.
The side surface (A) of the cylindrical cortical band at the equator was calculated as
A = p*Dcx*h.
The esteemed number of laterals (Nw) to be contained in the cortical band was computed as
Nw = A/Amesh.
For details see Supplementary_text., , # Modelling the cortex and hypothesis for the “head” of *Suppiluliumaella schlagintweitii* n.sp.

[https://doi.org/10.5061/dryad.n5tb2rc51](https://doi.org/10.5061/dryad.n5tb2rc51)

A procedure to evaluate the arrangement of cortical laterals is here proposed. The method applies to cylindrical thalli with primary laterals assembled in whorls. The meshes are assumed to be equidimensional in form of regular hexagons. Model with irregular hexagons could be applied if periodical inequidimensional laterals occur or if horizontal/vertical close packing of laterals make to exclude the regular density in all directions.

## Description of the data and file structure

Supplementary_text: A description of how modelling the cortex in dasycladaeans.
Supplementary_Figure1: Three examples of dasycladales with cortex in axial view and transversal view.
Supplementary_Figure2: Arrangements of cortical meshes.
Supplementary_Figure3: Arrangements of regular cortical meshes.
Supplementary_Figure4: “Head” ...