Stenorhynchosaurus munozi type locality (Cretaceous of Colombia)

Where: Boyaca, Colombia (5.7° N, 73.6° W: paleocoordinates 3.8° N, 42.2° W)

When: Gerhardtia sartousiana ammonoid zone, Arcillolitas Abigarradas Member (Paja Formation), Barremian (129.4 - 125.0 Ma)

• The skeletal remains were found in ‘Segmento C’ (Etayo Serna, 1968) of the Arcillolitas Abigarradas Member of the Paja Formation. The taxonomic identi cation of ammonite genera and species within the family Pulchelliidae Douvillé, 1890 follows Vermeulen (2003). According to Vermeulen (2003), the genus Gerhardtia Hyatt, 1903 includes the species G. sartousiana (D ́Orbigny, 1841), G. provincialis (D’Orbigny, 1850), and G. galeatoides (Karsten, 1856). Only the latter two species have been documented from the Villa de Leiva region under di erent speci c names (Vermeulen, 2003; Vermeulen & Klein, 2006).

•In the biostratigraphic zonation of the Barremian stage around Villa de Leiva, based on the family Pulchelliidae (Bürgl, 1956), Gerhardtia Hyatt, 1903 is treated as a subgenus of Heinzia Sayn, 1890. A similar taxonomic approach is followed by Patarroyo (2004). Bürgl stated: ‘Heinzia (Gerhardtia) is restricted in Colombia to the upper part of the middle Barremian’ (translated from Bürgl, 1956). The Barremian ammonite zonation proposed by Patarroyo (2000, 2004) for the Villa de Leiva region includes the ‘Heinzia (Gerhardtia) veleziensis Zone’ which represents the lowest zone of the Colombian upper Barremian. However, Vermeulen (2003) synonymized Heinzia (Gerhardtia) veleziensis (Hyatt, 1903) and Heinzia (Heinzia) colleti Bürgl, 1956 with Gerhardtia galeatoides, and considered Carstenia lindigii (Karsten, 1856) as a synonym of Gerhardtia provincialis.

•In the ‘Heinzia (Gerhardtia) veleziensis-Zone’, the ammonite assemblages recorded at Loma La Yesera and Loma de Monsalve in the Villa de Leiva region by Patarroyo (2000), contain the same species as those mentioned by Etayo Serna (1968), from a section in Loma la Cabrera, near where the pliosaurid was discovered. Hampe (2005: p. 38) referring to the pliosaurid discussed here wrote: “the age of the specimen [VL17052004-1] can be determined from numerous nds of the ammonite Heinzia sp. which are late Barremian in age (Patarroyo, 2000)”.

•In situ ammonites from the mudcracked argillaceous limestone 0.6 m below the pliosaurid skeleton are well- preserved internal moulds with rusty-colored weathering on their exposed surfaces; they are identi ed as G. galeatoides (Karsten, 1856) (MP-250604/2a, c) (Figure 4S a, b and c, http://www.raccefyn.co/index.php/raccefyn/ article/downloadSuppFile/239/1252), and G. provincialis (D ́Orbigny, 1850) (MP-110804/1, MP-110804/3, MP- 250604/2b) (Figure 4S d, e, f and g). The ammonite body fossil (MP-110804/2), and specimens now preserved as latex casts (MP-171108/1, 2) (Figure 4S h, i and j) recovered from the calcareous in lling of the pliosaurid skull are identi ed as G. galeatoides (Karsten, 1856) [ammonite determinations undertaken by F.E.-S.].

•The ammonite zonation of the French Barremian (Vermeulen, 2003) has in part has been adopted by the IUGS (Reboulet & Hoedemaeker, 2006; Reboulet, et al., 2014), and was used here to estimate the age of the pliosaurid bearing beds. The two ammonite species G. galeatoides and G. provincialis, collected both below and within the skull of the pliosaurid, permits recognition of the Gerhardtia provincialis Subzone of the Gerhardtia sartousiana Zone of the lower part of the upper Barremian (i.e. early late Barremian) of the scheme adopted by the IUGS (Reboulet & Hoedemaeker, 2006: Reboulet, et al., 2014).

Environment/lithology: marginal marine; lithified claystone

• The skeleton was found articulated in a variegated kaolinitic claystone (Light Brownish Gray 5YR6/1, Light Greenish Gray 5GY8/1 and Light Gray N7 (Rock-Color Chart Committee, 1963)) 0.6 m above a thin bed of argillaceous limestone with large, rusty-colored calcareous concretions (Moderate Reddish Brown 10R 4/6) that were up to 1 m in diameter and which show mud-cracked surfaces (Figure 3S, http://www.raccefyn.co/index.php/raccefyn/article/ downloadSuppFile/239/1251).

Size class: macrofossils

Collected by Jorge Muñóz in 2000

Collection methods: quarrying,

Primary reference: M. E. Páramo-Fonseca, M. Gómez-Pérez, L. F. Noé and F. Etayo-Serna. 2016. Stenorhynchosaurus munozi, gen. et sp. nov. a new pliosaurid from the Upper Barremian (Lower Cretaceous) of Villa de Leiva, Colombia, South America. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 40(154):84-103 [V. Fischer/V. Fischer]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 191664: authorized by Valentin Fischer, entered by Valentin Fischer on 08.02.2018

Creative Commons license: CC BY (attribution)

Taxonomic list

• Several ammonites were recovered from one of these concretions (SGC registered numbers MP-110804/1 and MP-250604/2a, b, c). One additional ammonite body fossil (MP-110804/2), along with several ammonite impressions from which latex moulds were made (MP-171108/1-5), were recovered from within the pliosaurid skull which was partly lled with ne calcareous matrix. Ammonite specimens and moulds are preserved in the collections of the Servicio Geológico Colombiano (SGC), Bogotá, Colombia.
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Reptilia
 Plesiosauria - Pliosauridae
Stenorhynchosaurus munozi n. gen. n. sp.
Stenorhynchosaurus munozi n. gen. n. sp. Páramo-Fonseca et al. 2016 plesiosaur
VL17052004-1, a nearly complete pliosaurid skeleton, lacking fragments of the left anterior paddle, the right posterior paddle and the tail (Figure 1). The specimen repository is the paleontological collections of the Museo Geológico José Royo y Gómez, Servicio Geológico Colombiano (SGC).