Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela)

Abstract

The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats.

Late Miocene chondrichthyans from Lago Bayano, Panama: Functional diversity, environment and biogeography

“…Waite, 2016). This fauna is therefore Tortonian in age and correlative with the other important chondrichthyan-bearing units in Central and South America, including the Gatun Formation and Alajuela Formation of central Panama (Gillette, 1984;Pimiento et al, 2013a;MacFadden et al, 2017), Angostura Formation of Ecuador (Carrillo-Briceño et al, 2014), and upper Urumacro Formation of Venezuela (Carrillo-Briceño et al, 2015b).…”

A Late Miocene Pipine Frog from the Urumaco Formation, Venezuela

“…The Neogene localities in the Urumaco Basin have so far yielded a large number of marine and continental vertebrates belonging to several major clades (Sánchez-Villagra et al, 2010;Carrillo-Briceño et al, 2015) but amphibians had not been reported to date. Most of the continental taxa retrieved are large sized, some being 'gigantic', such as the crocodilians Gryposuchus and Purussaurus, the turtle Stupendemys and the rodent Phoberomys (among others, Sánchez-Villagra et al, 2010;Scheyer et al, 2013).…”

Neogene Caribbean elasmobranchs: Diversity, paleoecology and paleoenvironmental significance of the Cocinetas Basin assemblage (Guajira Peninsula, Colombia)

“…S5). Extant sharks and rays as a whole have a wide range of diets; however, each taxon has specific food preferences (see Cortés et al, 2008;Klimley, 2013) that could be used to infer dietary strategies of their fossil relatives (e.g., Carrillo-Briceño et al, 2016a). Information regarding feeding ecology (dietary composition and behavior) of extant and relative species of the taxa recorded in the Cocinetas assemblages (Table S3) was compiled from Cortés et al (2008), Compagno et al (2005), Weber (2011), Ebert andStehmann (2013) and the FishBase website (Froese and Pauly, 2017).…”

“…This region presents extensive and well-exposed sedimentary deposits spanning the last 25 Myr . The paleoenvironments are characterized by a transition from shallow marine deposits to a fluvio-deltaic system , with a rich fossil record of invertebrates and vertebrates (Aguilera et al, 2013(Aguilera et al, , 2017bMoreno et al, 2015;Cadena and Jaramillo, 2015;Amson et al, 2016;Carrillo-Briceño et al, 2016b;Moreno-Bernal et al, 2016;Pérez et al, 2016). Ages for many of the fossiliferous units in the sequence have been estimated using Sr isotope stratigraphy (see Hendy et al, 2015).…”

“…But reports on chondrichthyans from the Neogene of Colombia are scarce. Previous reports from the Cocinetas Basin include fossil elasmobranchs without taxonomic description (Lockwood, 1965), a checklist of 14 families and the description of a small assemblage of 13 taxa from the early Miocene Uitpa Formation (Carrillo-Briceño et al, 2016b).…”