Fungal spores in Caribbean mangrove sediments, dataset from southeastern Mexico

Most paleoecological investigations use different biotic or abiotic proxies for climate and environmental reconstructions. Although fossil pollen is one of the most used biological proxies, Non-Pollen Palynomorphs (NPPs), especially fungal spores and tissues, have an underestimated potential to infer local and regional climate dynamics. This dataset describes the most common Non-pollen palynomorphs of fungal origin from mangrove sediments in the Caribbean Sea, southeastern Mexico. A detailed descriptive Atlas is presented, with light micrographs taken from routine pollen slides in paleoecological reconstructions. Microphotographs were included to facilitate their identification. A total of 59 spores, 4 tissues, 2 hyphae, and 11 unidentified fungal palynomorphs are described.


Subject
Earth and Planetary Sciences -Paleontology Specific subject area Non-pollen Palynomorphs -Fungal spores and tissues Type of data Image and Table How the data were acquired Micrographs were acquired via Carl Zeiss -Primo Star light microscope with 5 Megapixels integrated camera.Images were obtained via 400X magnification and processed with AxioVision software.Fungal NPP counts and identification was made from prepared pollen slides at 2.5cm intervals of a 150cm long sediment core retrieved at Laguna Cementerio, Mexico.Data format Raw Description of data collection Fungal spores, tissues, and hyphae were identified based on morphometric measurements and analysis of apertures, wall thickness, shape, number of segments, and texture.Various NPPs identification keys were used [1][2][3][4][5][6][7] .The taxa were named with the abbreviation ECO (El Colegio de la Frontera Sur) followed by a numbering.Data source location • City/Town/Region: Laguna Cementerio, Caribbean Sea, southeastern Mexico ( Fig. 1 )

Objective
Our main objective is to improve Late Holocene paleoenvironmental reconstructions of mangroves of the Caribbean basin.Proper fungal spores, tissue, or structure identification could reinforce, or complement, climate and ecological interpretations from other proxies in mangrove sediments.This dataset also aims to offer paleoecologists easy-access fungal origin non-pollen palynomorphs description with their environmental affinities ( Fig. 1 ).

Data Description
Fungal spores and tissues have been used as complementary environmental indicators in paleoenvironmental research since the early 1970s [8] .They are some of the most common NPPs found in mangrove sediments that exhibit environmental conditions caused by erosion, marine intrusion, anthropogenic activity, humidity, or salinity [ 3 , 9 ].Although several paleoenvironmental studies have reported fungal presence and concentrations as environmental indicators [10][11][12] , identification keys in Mexico are notably rare [13] , and virtually non-existent in the Yucatan peninsula, complicating their use as an effective proxy for specific environmental conditions.Fungal activity in mangroves is relevant for nutrient cycling and ecosystem regulation.Fungi in mangrove sediments participate in various ecological processes.Key roles of fungi in mangrove sediments include decomposition, symbiotic relationships, nutrient cycling and soil structure.
This dataset presents a detailed description and environmental affinities of fungal origin NPPs, supplemented with light micrographs to form a descriptive atlas of fungal spores and tissues found in Late Holocene mangrove sediments of the Yucatan peninsula.It is aimed to be used as a reference resource in future paleoenvironmental studies in the Caribbean region.Original counts and Fungal NPPs' ID from pollen slides can be found in Mendeley's data repository [14] .In the "Morphotypes" sheet, the identified fungal structure is presented.Taxa were named with the abbreviation ECO (El Colegio de la Frontera Sur) followed by a numbering.Individual counts in every sample can be found in "Counts" sheet.Descriptions are organized according to taxa systematics, referring to specific light micrographs in Plates 1 , 2 , 3 .

GLOMEROMYCOTA Division
Class GLOMEROMYCETES Order GLOMERALES Family GLOMERACEAE Genus Glomus (Tul.And C. Tul.1845) The genus Glomus is considered one of the most abundant for having a close symbiosis with the plants of terrestrial ecosystems, they are considered arbuscular vesicle fungi.In paleoecological studies, Glomus is used as an indicator of soil erosion processes due to deforestation recorded in lake deposits.ECO 27 .-Transparentspores with a yellowish edge, belong to the group of ascomycetes.They are found alone or in groups of up to 6 spores.Spores with diameters between 6.5 to 10.3 μm, wall thickness of 0.3 μm.Spores present subtending hyphae of an approximate length of 3.2 μm (Plate.II, 27).
ECO 28 .-Sporeglobose of 7-8 μm, dark brown, verrucose, thick-walled.Globular spore of the group of ascomycetes, with a verrucose texture and a yellowish hue, has a thick wall of dark yellow color.The diameter varies between 7 to 8.1μm, thin-walled of 0.9 to 1.9 μm (Plate II, 28).

ASCOMYCOTA Division
Class DOTHIDEOMYCETES Family MICROTHYRIACEAE Genus Microthyrium (Dems 1841) The genus Microthyrium is considered a saprophytic group, in the few available studies, the presence of these morphotypes indicates conditions of higher humidity.

Hyphae
Hyphae are fungal structures difficult to identify to species level.Authors such as Prager et al. [6]

Experimental Design, Materials and Methods
A 150 cm long sediment core was retrieved in Laguna Cementerio, a coastal lagoon under a subtropical climate regime located in Southeastern Mexico.Mangrove forest surrounds the coring site, and the dominant species are Rhizophora mangle, Conocarpus erectus, and Laguncularia racemosa .The climate is subhumid, with an average annual rainfall of 1,200 to 1,500 mm, and maximum temperature of 35 °C and a minimum of 14 °C [15] .
The NPP identification and description were performed from sediment samples taken along the core.A total of 56 sediment samples were processed and analyzed.NPPs were extracted using the conventional pollen extraction technique [ 16 , 17 ], using KOH and HCl solutions to remove humic acids and carbonates, respectively.A glycerinated gelatin mounting medium was used for microscope slides.
Identification was performed up to the finest possible taxonomic level using various keys developed for NPPs [ 1-7 , 18-20 ].Morphometric measurements were made as well as the description of each morphotype, the thickness of the wall, color, texture, and shape of the spore or tissue were considered to separate the morphotypes.

Ethics Statements
This work did not involve any human or animal subjects or experiments