Morphometric analysis of the conodont Chiosella timorensis (Nogami) from the early Anisian of Romania and China, and its significance for the definition of the Olenekian-Anisian Boundary

The conodont Chiosella timorensis (Nogami) has long been proposed as a biotic proxy for identifying the Olenekian-Anisian Boundary (OAB). However, uncertainty regarding the relationship between this species and its presumed ancestor, Ch. gondolelloides (Bender) and its stratigraphic range have cast doubt on its suitability as a proxy. Morphometric analysis of large populations of Chiosella from the Global Stratotype Section and Point candidate at Deşli Caira, as well as other OAB sections in south China, demonstrate that most morphological variation in this genus is caused by variability in the position of the cusp, not the length of the mid-lateral rib (traditionally used to separate the species Ch. gondoelloides and Ch. timorensis). Furthermore, there is little to no stratigraphic separation between the two species, and no obvious trend in any of the investigated sections of a morphological shift from one species to the other with increasing stratigraphic height. Finally, when investi..., A total of 168 specimens of Chiosella from Desli Caira, Guandao and Mingtang were utilized for the morphometric analysis. 
Specimens were first photographed in lateral view, and the JPEG file were converted ro TPS files using the software TpsUtil, before the positions of all landmarks were identified per specimen in the software TpsDig. Eleven landmarks were utilized, in an attempt to capture the morphology of the specimens. 
Morphometric analyses were subsequently conducted using the software MorphoJ. First, a generalized Procrustes analysis was conducted on each species dataset, which minimizes all variation in specimen position, size, and rotation, in order to conserve only variation in specimen shape. Then, a wireframe model was created for each species, where landmark points are linked in a consistent manner to better facilitate visualization of form changes. Finally, eigenanalyses were carried out, both Principal Components Analysis (PCA) and Canonical Variate Analysis (..., , # Data from: Morphometric analysis of the conodont *Chiosella timorensis* (Nogami) from the early Anisian of Romania and China, and its significance for the definition of the Olenekian-Anisian Boundary

[https://doi.org/10.5061/dryad.vx0k6dk2d](https://doi.org/10.5061/dryad.vx0k6dk2d)

## Description of the data and file structure

This readme file was generated on 2024-11-15 by Shunling Wu.

## Data and file overview

File List:

1._conodonts_landmark.csv

2._conodonts_species_PCA.csv

3._conodonts_sections_CVA.csv

4._conodonts_Desli Caira_beds_CVA.csv

5._conodonts_Guandao_beds_CVA.csv

6._conodonts_Mingtang_beds_CVA.csv

7._Individual size.csv

### Data-specific information for: 1._conodonts_landmark.csv

This file contains the coordinates of the landmark points placed on the element contour of each studied specimen. The data were made by TpsDig and TpsUtil.

Number of variables (columns): 15

Number of specimens (rows): 168

Variable List: sections, species, number, sample, (X1, Y1...,