DOI: 10.5061/dryad.83bk3j9zw
title: A new species and a new combination in Protoperidinium sect. Oceanica (Peridiniales, Dinophyceae) from Vietnamese waters

description: In this study, we described and illustrated details of a new species,
 Protoperidinium vietnamicum sp. nov., from Vietnamese coastal waters and
 Protoperidinium curvicorne (Böhm) comb. Nov. is proposed as a new
 combination. Each cell's size range (length, width, and depth) was
 measured, and the morphological features of both species described here
 and selected related species in the Oceanica section were compared. In
 addition, the ecology and distribution of both species were given.
description: Sampling These datasets were created from
 phytoplankton samples collected with vertical net hauls (mesh size – 25 µm
 and net diameter – 30 cm) at locations along Vietnamese coastal water,
 proven from associated projects in Vietnam.
 Analyses <strong>Take
 photographs:</strong> Cells were observed by
 light microscopy (LM) and scanning electron microscopy (SEM). LM was
 performed using a Leica DMLB (Solms, Germany), and a digital camera DP71
 (Olympus) was used for micro-photography. SEM was scanned on the Hitachi
 S4800 Field-Emission SEM (Hitachi Manufacturing Institute) at a voltage of
 10.0 kV and a working distance of 8.3–9.2 mm. 
 <strong>Biometric analyses:</strong>
 Morphological measurements of cells from each photographed cell
 were carried out by light microscopy using imaging software (Standard
 cellSens ver. 3.1.1, Olympus, Tokyo, Japan). 
 The length (L) of the cell was measured from the
 epitheca's apex to the hypotheca's antapex.
 The width (W) of the cell was measured
 directly in front of the cingulum or behind it, not including the cingular
 lists. Depth (or height in some
 literature) (D) was measured in its widest part in lateral view, not
 including the cingular lists. 
 L/W ratio showing the variability in the cell size between
 <em>Protoperidinium</em> species section
 <em>Oceanica</em>. 
 <strong>Ecology and distribution:</strong>
 Physical conditions such as temperature,
 salinity, and depth profile were measured at each sampling time using
 SeaBird 19 plus CTD (Sea-Bird Scientific, USA). Data from CTD were
 downloaded and processed using software from the manufacturer.
 The GPS coordinates are collected at each
 station. NA denotes missing
 values. 
 <strong>Comparison of the morphological biometrical
 characterizations:</strong> The morphological
 characterizations of <em>Protoperidinium</em> species and the
 use of biometric terminology and abbreviations are as follows:
 Apical horn: forms the apex of the cell and
 is formed by the apical plates. 
 Antapical horns: typically formed by antapical plates.
 Cingulum: located approximately at the
 midpoint of the cell. When the cingulum is displaced, descending is the
 most common; the distal end is below the proximal end, which is always on
 the left side of the cell. 
 Sulcus: the longitudinal area on the ventral surface of the cell
 in <em>Protoperidinium</em> species, which is mainly in the
 ventral of the hypotheca. The
 names of the thecal plates are abbreviated according to the Kofoid
 tabulation system as follows: 
 Intercalary plates (1a-3a) at epitheca do not touch the apex and
 the cingulum; the shape of the second anterior intercalary (2a) plate,
 such as quadra (four-sided), penta (five-sided), and hexa
 (six-sided). <strong>Box
 plots:</strong> Box plots were created by RStudio
 using the package "ggplot2" (Wickham, 2009). Wickham, H. (2009)
 Ggplot2: Elegant Graphics for Data Analysis. 2nd Edition, Springer, New
 York. https://doi.org/10.1007/978-0-387-98141-3.
description: Title dataset: A new species and a new combination in *Protoperidinium*
 sect. Oceanica (Peridiniales, Dinophyceae) from Vietnamese waters
 Give a brief summary of
 dataset contents, contextualized in experimental procedures and results.
 **Supplementary Figure S1.** Box plots of morphological biometric
 variation of thirteen *Protoperidinium* species belonging to section
 *Oceanica* in Vietnamese waters. Box diagrams show mean values (horizontal
 lines) and standard deviation bars. Described in Methods: Biometric
 analyses and box plots. **Supplementary Table S1.** Ecology and
 distribution of *Protoperidinium vietnamicum* sp. nov. and *P. curvicorne*
 (Böhm) comb. nov. in Vietnamese and Iranian waters. Described in Methods:
 Ecology and distribution **Supplemental Table S2.** Summarise the
 morphological biometrical characterizations of *Protoperidinium* species
 belonging to the section *Ocenica *from Vietnamese waters. Described in
 Methods: Comparison of the morphological biometrical characterizations.
 Description of the data and file structure Data-specific information for:
 Supplemental-Figure-S1.csv 1\. Number of variables: 5 2\. Number of
 cases/rows: 152 3\. Variable List: * Species name: Protoperidinium species
 name. * Length (μm): the length of each cell was measured. * Width (μm):
 the width of each cell was measured. * Depth (μm): the depth of each cell
 was measured. * L/W ratio: the length-to-width ratio of each cell was
 measured. 4\. Missing data codes: NA (data not applicable) 5\. Specialized
 formats or other abbreviations used: None P = Protoperidinium, L = Length,
 W = Width, D = Depth Data-specific information for:
 Supplemental-Table-S1.csv 1\. Number of variables: 9 2\. Number of
 cases/rows: 28 3\. Variable List: * Species name: Protoperidinium species
 name. * Sites: where species was found. * Sampling locations: where sample
 was collected. * Latitude (°N): the latitude of a site where sample was
 collected (degrees north). * Longitude (°E): the longitude of a site where
 sample was collected (degrees east). * Collection date: the date on which
 the sample was collected. * Water depth (meter): The depth of water
 measured at the sampling location. * Temperature (°C): the temperature of
 water measured while the sample was collected. * Salinity (Psu): the
 salinity of water measured while the sample was collected. 4\. Missing
 data codes: NA (data not applicable) 5\. Specialized formats or other
 abbreviations used: Jan = January, Feb = February, Mar = March, Apr =
 April, Jun = June, Jul = July, Aug = August, Oct = October, Nov = November
 Data-specific information for: Supplemental-Table-S2.csv 1\. Number of
 variables: 10 2\. Number of cases/rows: 13 3\. Variable List: * Species
 name: Protoperidinium species name. * Apical horn: the morphological
 characteristics of apical horn. * Cingulum / Descending width cingulum
 offset: the morphological characteristics of cingulum/Cingulum descending
 with about \ times girdle widths. * Antapical horns: the morphological
 characteristics of antapical horns. * Sulcus: the morphological
 characteristics of sulcus in ventral of the hypotheca. * Type of 2a plate:
 the shape of the second intercalary plate observed in the dorsal of
 epitheca. * Length (μm): the length of each cell was measured. * Width
 (μm): the width of each cell was measured. * Depth (μm): the depth of each
 cell was measured. * L/W ratio: the length-to-width ratio of each cell was
 measured. * References: the source of information of data. 4\. Missing
 data codes: None 5\. Specialized formats or other abbreviations used: None