Fossil snakes from the Eocene of India: New material with comments on phylogenetic relations and biogeographic and palaeoecological implications
Data files
Jan 21, 2025 version files 9.13 KB
-
Datta_and_Bajpai_Supplementary_Dataset_1.txt
7.22 KB
-
README.md
1.91 KB
Abstract
Eocene snakes of India have the potential to shed light on the nature of snake diversification on the subcontinent following the Deccan volcanism at the Cretaceous–Paleogene boundary (K-Pg), when India was still a northward drifting isolated landmass prior to its collision with Asia. Here we report a diverse snake fauna from the Eocene of Kutch, western India. The fauna, dominated by aquatic forms, include palaeophiids, a giant madtsoiid and a possible nigerophiid. The palaeophiids from the middle Eocene (late Lutetian) comprise ?Palaeophis and Pterosphenus rannensis sp. nov. Together, these taxa enrich the record of fossil snakes the poorly known late Lutetian of India and represent the youngest record of Palaeophiidae from the Indian subcontinent. Pt. rannensis shows intermediate morphology between Palaeophis and Pterosphenus-grade snakes, and is phylogenetically the earliest-diverging member of Pterosphenus. Additionally, the middle Eocene Pt. biswasi is reassessed and retained as a valid taxon based on pterapophyseal morphology and overall form. Biogeographic considerations highlight the importance of Indian fossil record in understanding the origin and diversification of the genus Pterosphenus. The prevalence of niche partitioning is suggested for the palaeophiids, with Pt. rannensis recovered from a tidal setting and ?Palaeophis sp. from a marsh/swamp setting. The new Indian madtsoiid from the middle Eocene (early Lutetian) represents a sympatric taxon with the terrestrial/semi-aquatic giant Vasuki indicus co-existing in a back swamp marsh setting. The early Eocene (Ypresian) nigerophiid is among the oldest Cenozoic occurrences of this family globally.
README: #Fossil snakes from the Eocene of India: New material with comments on phylogenetic relations and biogeographic and palaeoecological implications
#Datta and Bajpai_Supplementary Dataset 1
https://doi.org/10.5061/dryad.z8w9ghxq2
Description of the data and file structure
This folder contains the dataset (Datta and Bajpai_Supplementary Dataset 1) used to perform the phylogenetic analysis present in our paper. The dataset is a .TXT file that contains the following:
- List of characters used in our analysis and the different character states of these characters. A separate character list containing all characters and their states, the source from where the characters were taken and reasoning being modification of some characters is also provided with the manuscript as an appendix (Appendix 3).
- A list of taxa used, where against each taxon the scoring of each characters (character states) are mentioned. The scoring includes binary codes (e.g., 0, 1, 2). Incase a character could not be scored for a particular taxon, '?' was used.
#Software
This data set (Supplementary Dataset 1) was edited using the software PAUP* version 4 3.99.169.0, and run using TNT version 1.6. To perform the phylogenetic analysis the software (TNT) memory was set to retain 10,000 trees and a display buffer of 10 Mb. The Traditional Search option was used where the analysis constrains included 50 replications of Wagner trees, with bisection reconnection as the swapping algorithm, and 10 trees saved per replication. A detailed description of how the analysis was performed is given in the paper.
Access information
Data was derived from the following sources:
- The source of information for the dataset for the phylogenetic analysis and information on the taxa used are provided in the paper and Appendix 3 that is associated with the paper.