Dinosaurs had South American origin, geodispersal routes

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

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Sulagna Sen, Sourav Bagchi & Sanghamitra Ray (2025)
Biogeographical network analysis of the Late Triassic dinosaurs and new insights on their geodispersal routes
Gondwana Research (advance online publication)
doi: https://doi.org/10.1016/j.gr.2025.04.007
https://www.sciencedirect.com/science/article/abs/pii/S1342937X25001327


Highlights

First metric study on Late Triassic dinosaurs proposes a new model suggesting:
Their South American origin,
Simultaneous eastern and northern dispersal from epicenter,
Sauropodomorph exchange between South Africa and Europe,
Indian dinosaurs show strong affinity with South American assemblage, and.
Sauropodomorphs emerged in India far earlier than previously anticipated.

Abstract

Dinosaurian paleobiogeography has remained a compelling domain of interest in the field of vertebrate paleontology over the past few decades, though there has been little/no work with respect to the Late Triassic dinosaurian remains from India. This study investigates the probable centers of origin of the early dinosaurs that included various lineages such as Sauropodomorpha, Herrerasauria and Theropoda through the Late Triassic period using a phylogeny-based network analysis with especial emphasis on the Indian dinosaurs including the new skeletal elements recovered from the late Carnian to early/ middle Norian Tiki Formation of India. Our phylogenetic study positions Tawa as sister taxa to other late diverging herrerasaurids near the base of Herrerasauria, supports the placement of Coelophysis near the base of Neotheropoda and proposes alternative placements for a few sauropodomorphs. Networks of the Late Triassic dinosaurs including the contemporary sauropodomorphs and Herrerasauria exhibit nearly identical topologies with strong interconnectivity. Based on the network analysis, we propose South American origin for the Late Triassic Dinosauria with two primary dispersal trajectories leading to the Laurasian and Eastern Gondwanan landmasses simultaneously. We propose a new model that showed a closer faunal relationship between the south African and European provinces suggesting intercontinental faunal exchange and paleomigration particularly during the later stages of sauropodomorph evolution. Community detection algorithms revealed that the Late Triassic dinosaurian assemblage of India showed a stronger affinity with that of the South American fauna. Therefore, this study highlights the importance of phylogeny-based network analysis in the deduction of origination center and dispersal routes of the fossil animals.

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[Ben Creisler]

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A new comment:

Rodrigo Temp Müller, Maurício Silva Garcia, Lísie Vitória Soares Damke & André Oliveira Fonseca (2025)
Comment on “Biogeographical network analysis of the Late Triassic dinosaurs and new insights on their geodispersal routes” by Sen et al.

Gondwana Research (advance online publication)

doi: https://doi.org/10.1016/j.gr.2025.05.013
https://www.sciencedirect.com/science/article/abs/pii/S1342937X25001637



Sen et al. (2025) investigated the biogeography and geodispersal routes of Late Triassic dinosaurs using a new phylogenetic topology derived from an updated data matrix originally published by Langer et al. (2022). Whereas the new dinosaur specimens from the Tiki Formation (India) and biogeographic results presented by Sen et al. (2025) are insightful and reinforce some previous hypotheses, the phylogenetic analysis conducted in the study, which served as a basis for their biogeographic analysis, raises concerns that warrant further attention. These issues are discussed below.
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