Journal of Vertebrate Paleontology ISSN: 0272-4634 (Print) 1937-2809 (Online) Journal homepage: https://www.tandfonline.com/loi/ujvp20 A new specimen of Platypterygius sachicarum (Reptilia, Ichthyosauria) from the Early Cretaceous of Colombia and its phylogenetic implications Erin E. Maxwell, Dirley Cortés, Pedro Patarroyo & Mary Luz Parra Ruge To cite this article: Erin E. Maxwell, Dirley Cortés, Pedro Patarroyo & Mary Luz Parra Ruge (2019): A new specimen of Platypterygiussachicarum (Reptilia, Ichthyosauria) from the Early Cretaceous of Colombia and its phylogenetic implications, Journal of Vertebrate Paleontology To link to this article: https://doi.org/10.1080/02724634.2019.1577875 View supplementary material Published online: 12 Apr 2019. Submit your article to this journal View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ujvp20 Journal of Vertebrate Paleontology e1577875 (12 pages) © by the Society of Vertebrate Paleontology DOI: 10.1080/02724634.2019.1577875 ARTICLE A NEW SPECIMEN OF PLATYPTERYGIUS SACHICARUM (REPTILIA, ICHTHYOSAURIA) FROM THE EARLY CRETACEOUS OF COLOMBIA AND ITS PHYLOGENETIC IMPLICATIONS ERIN E. MAXWELL, *,1 DIRLEY CORTÉS, 2,3,4 PEDRO PATARROYO,5 and MARY LUZ PARRA RUGE6 1Staatliches Museum für Naturkunde, Rosenstein 1, 70191 Stuttgart, Germany, [email protected]; 2Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Panama; 3Grupo de Investigación Biología para la Conservación, Universidad Pedagógica y Tecnológica de Colombia, Avenida Central del Norte 39-115, Tunja, Colombia, [email protected]; 4Redpath Museum, McGill University, 859 Sherbrooke St. W., Montreal QC H3A 0C4, Canada, [email protected]; 5Departamento de Geociencias, Universidad Nacional de Colombia, Sede Bogotá, Cr. 30 N. 45–03. Bogotá, Colombia, [email protected]; 6Centro de Investigaciones Paleontológicas, km 4 Vía Santa Sofía, Villa de Leyva, Colombia, [email protected] ABSTRACT—Platypterygius sachicarum is one of the few Lower Cretaceous ichthyosaurian species described from the Hauterivian–Aptian-aged Paja Formation, the most complete Lower Cretaceous sedimentary sequence in northern South America. To date, P. sachicarum has been described only from a single skull, limiting morphological, stratigraphic, and phylogenetic comparisons. Here, we describe a new skull and associated postcranium of upper Barremian age from Villa de Leyva, Colombia, which represent the first documented postcranial remains of this species and enable detailed comparison with other Early Cretaceous ophthalmosaurid ichthyosaurs. Platypterygius sachicarum shares many morphological similarities with contemporaneous taxa from Europe but differs in both skull and tooth morphology from coeval South American species from northern South America and from the eastern Pacific. The additional data provide new diagnostic characters for this species and resolve the position of P. sachicarum as part of a polytomy of other species historically referred to Platypterygius. However, as with previous analyses, all recovered clades are poorly supported. The rich vertebrate fossil record of the Paja Formation provides an unparalleled opportunity to explore paleobiogeographic and paleoecological questions pertaining to Cretaceous marine reptiles; however, in most cases, a robust stratigraphic and phylogenetic framework remains elusive. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Maxwell, E. E., D. Y. Cortés, P. Patarroyo, and M. L. Parra Ruge. 2019. A new specimen of Platypterygius sachicarum (Reptilia, Ichthyosauria) from the Early Cretaceous of Colombia and its phylogenetic implications. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2019.1577875. INTRODUCTION 2016), and one described based only on forelimb material (P. hauthali, from Argentina and Chile; Fernández and Aguirre- The Barremian–Aptian interval represents a key window for Urreta, 2005; Pardo-Pérez et al., 2012). This has led to uncertainty ichthyosaurian evolution. Cretaceous ichthyosaurs were at their regarding the relationship, and possible synonymy, of P. hauthali most taxonomically diverse and morphologically disparate at and P. sachicarum (McGowan and Motani, 2003); the relationship this time (Fischer et al., 2016). However, a major loss of lineages of Muiscasaurus catheti to P. hauthali is also uncertain. was ongoing, with the last diagnostic records of both non-ophthal- One of the richest sources of Lower Cretaceous marine ver- mosaurid parvipelvians and ophthalmosaurines occurring during tebrates in northern Gondwana is the Paja Formation, which is this interval and, concomitantly, the diversification of the large Hauterivian–Aptian in age (Etayo Serna, 1968; Patarroyo, platypterygiine taxa historically referred to the genus Platyptery- 2004) and crops out in the Colombian Eastern Cordillera gius (Fischer et al., 2016). The ichthyosaurian fossil record during around Villa de Leyva, Boyacá Department, Colombia. Fossil ver- the Barremian–Aptian is quite fragmentary, characterized by tebrates, including ichthyosaur remains, are abundant and have many genera and species represented only by a single, usually been known since the 1940s (reviewed by Páramo Fonseca, extremely incomplete, specimen. Moreover, the Gondwanan 2015). Description of the vertebrate fauna is ongoing, with most record is particularly patchy, especially in terms of skeletal com- of the described species from this formation named within the pleteness: only three species are known, one based solely on past 5 years (Cadena, 2015; Cadena and Parham, 2015; Carballido cranial material (Platypterygius sachicarum from Colombia; et al., 2015;Maxwelletal.,2016; Páramo-Fonseca et al., 2016; Páramo, 1997), one based on a partial skull and anterior vertebral Gómez-Pérez and Noè, 2017). The ichthyosaurs Platypterygius column (Muiscasaurus catheti from Colombia; Maxwell et al., sachicarum and Muiscasaurus catheti have both been described from the Paja Formation. Platypterygius sachicarum has been cited as being lower Aptian in age (Hampe, 2005), whereas Muis- *Corresponding author. casaurus catheti is stratigraphically indeterminate. Color versions of one or more of the figures in the article can be found Here, we describe the first associated cranial and limb material online at www.tandfonline.com/ujvp. of an ichthyosaur from the Paja Formation. We refer this Published online 12 Apr 2019 Maxwell et al.—New material of Platypterygius sachicarum (e1577875-2) specimen to Platypterygius sachicarum, making this the first post- and overlain by abundant bedding-parallel fibrous calcite (‘beef’), cranial material documented for the species and permitting more with calcite-cemented concretions weathering out of the shale and detailed comparisons with ichthyosaurs from the Early Cretac- becoming concentrated on the surface. One fragmentary ammonite eous of Europe. was found in situ, in close proximity to the skeleton, and is referable Institutional Abbreviations—CIP, Centro de Investigaciones to Colchidites sp., indicating that CIP-GA-01042014 is uppermost Paleontológicas, Villa de Leyva, Colombia; DON, Museo Geoló- Barremian in age (∼125 Ma) (Patarroyo, 2000, 2004). Additional gico Nacional José Royo y Gómez, Bogotá, Colombia; QM, ammonites were surface-collected from the locality and provide Queensland Museum, Brisbane, Australia. an upper bound for the age of the specimen. This age estimate is con- sistent with the abundance of fibrous calcite at the locality (Forero- Onofre and Sarmiento-Rojas, 1985). MATERIAL The specimen consists of the skull and presacral vertebral The skeleton (CIP-GA-01042014) is a large ichthyosaur from the column in a clay matrix, collected in three blocks (Fig. 2A,B). It El Roble locality (Loma La Cabrera, ‘Finca los Morros,’ 5°39.923′N, was mechanically prepared from the reverse side by Juan Parra 73°32.305′W), Villa de Leyva, Boyacá, Colombia (Fig. 1), and was and Fredy H. Parra at the CIP. The quality of preservation is vari- found by the property owners Gustavo Amador and Carmenza able across the skeleton, with some areas showing a high degree Amador in 2014. The Arcillolitas Abigarradas Member of the of weathering. The first block contains the skull, preserved in left Paja Formation crops out at the locality (Fig 1C; Etayo Serna, lateral view. The second block contains the pectoral girdle, fore- 1965, 1968). The ichthyosaur is preserved in poorly lithified clay, limb, and dorsal vertebral column, all preserved in dorsal view, FIGURE 1. Locality information for CIP-GA-01042014. A, location of the department of Boyacá within Colombia and B, the location of Villa de Leyva within Boyacá; C, geological map of the Villa de Leyva region showing the localities of CIP-GA-01042014 and the holotype of Platypterygius sachi- carum, DON-19671 (modified from Etayo Serna, 1965, 1968). Maxwell et al.—New material of Platypterygius sachicarum (e1577875-3) suggesting that the skull was twisted relative to the postcranium. well preserved. The premaxilla bears teeth, but the preservation The third block contains the posterior dorsal and the anterior does not allow the presence of an alveolar groove to be assessed. caudal vertebral column, and a putative pelvic element. Based The anterior-most tip of the premaxilla is preserved; it is rounded on preservation, the skeleton was lying on its back on the sea