First report of the giant snake Gigantophis (Madtsoiidae) from the Paleocene of Pakistan: Paleobiogeographic implications

The osteology of the giant snake Gigantophis garstini from the upper Eocene of North Africa and its bearing on the phylogenetic relationships and biogeography of Madtsoiidae

“…There have been several referrals to Gigantophis since the discovery of the genus. These comprise occurrences from the middle-upper Eocene of North Africa, with additional materials from other localities in Fayum, Egypt (Andrews, 1906;McCartney and Seiffert, 2016), as well as from Libya (Hoffstetter, 1961b), and material from the lower Paleocene of Pakistan (Rage et al, 2014). Below we provide a critical reassessment of these referrals, based on our revised view of the Gigantophis garstini type material.…”

“…7A) was one of the few vertebrae figured by Andrews (1906). Consequently, it has persistently been used to characterize Gigantophis in the literature (e.g., Simpson, 1933;Hoffstetter, 1961b;LaDuke et al, 2010;Rage et al, 2014). The referral of NHMUK R3188 to Gigantophis is supported by the following features (features considered diagnostic marked with an asterisk): (1*) the very large size (postzygapophyseal width D 62 mm); (2*) low neural spine; (3) anteroposteriorly short neural spine reaching the zygosphene; (4*) presence of a rhombic termination on the posterior hemal keel; and (5) absence of subcentral and lateral foramina.…”

“…A lack of understanding of madtsoiid interrelationships also hinders our identification and recognition of the group's radiation, as well as biogeographic patterns. In particular, how and when Madtsoiidae achieved its wide Gondwanan and trans-Tethyan distribution is heavily debated (e.g., LaDuke et al, 2010;Mohabey et al, 2011;Vasile et al, 2013;Rage et al, 2014).…”

“…He also provided only a small set of measurements from three vertebrae. Although the 20 vertebrae that constitute the syntype material are accessioned in the Egyptian Geological Museum, Cairo (CGM), nearly all subsequent comparative work has been based either on the limited information provided by Andrews (1901Andrews ( , 1906 or on first-hand observations of high-quality casts stored in the Natural History Museum, London (NHMUK), combined with information from referred specimens (e.g., Head et al, 2009;Rage et al, 2014;McCartney and Seiffert, 2016). In particular, one referred specimen (NHMUK R3188), figured by Andrews (1906:pl.…”

“…As such, the published record of Gigantophis is extremely brief and insufficiently characterizes the genus. Consequently, the referral of other materials to Gigantophis (e.g., from the Paleocene of Pakistan; Rage et al, 2014), and its character scoring in the only phylogenetic analysis to include it (Vasile et al, 2013), should be treated with caution, as should biogeographic hypotheses based on these studies.…”