Giant longirostrine crocodylians from the Lower Miocene of Pakistan: new material and taxonomic review

Abstract This study, based on previously undescribed crocodylian remains from the Lower Miocene of the Bugti Hills (Balochistan, Pakistan), identifies at least three distinct species. It confirms the validity of the species initially identified as ‘ Gavialis ’ pachyrhynchus , establishing it as the sister taxon to the massive Miocene crocodylian Rhamphosuchus crassidens . Consequently, it is reclassified as Rhamphosuchus pachyrhynchus . Additionally, ‘ Gharialis ’ curvirostris is now acknowledged as a valid species under the new genus name Pseudogavialis , closely related to Gavialis . Another set of remains represents a third species, although the poor preservation hinders precise identification. The phylogenetic relationship between Tomistoma and Gavialis is one of the most debated issues in crocodylian phylogeny. Molecular analyses suggest a sister‐taxa relationship dating back to the Early Miocene, while morphological analyses place Gavialis at the base of the tree, diverging from ‘thoracosaurs’, with a Gavialoidea–Crocodyloidea split in the Cretaceous. The inclusion of newly described species in phylogenetic analyses yields variable outcomes, highlighting the sensitivity of results to the species considered. The insertion of Portugalosuchus azenhae , found as a ‘thoracosaur’, aligns with traditional morphological findings, while the inclusion of Indo‐Pakistani species of Rhamphosuchus supports the molecular hypothesis. Nevertheless, the large number of morphological gavialoids and ‘thoracosaurs’ makes the molecular result strongly stratigraphically incongruent. The inclusion of fossil species in the phylogenetic analyses significantly impacts our understanding of crocodylian relationships. Even when molecular results align with morphological data, the persistent stratigraphic incongruence does not resolve the Gavialis – Tomistoma dilemma.