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Western Mediterranean standard zonation of the Barremian Stage (Taken from Reboulet et al., 2014) and biostratigraphy correlated to the Colombian Barremian.
Source publication
Marine Barremian deposits are represented in different lithostratigraphic units in Colombia, from the central part of the country to the north. Up to the Upper Magdalena Valley, continental deposits have been reported in the Yaví Formation; although until now, only Aptian plant remains have been recognized.Marine deposits include the shales and bio...
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... now, it has not been clear if Spitidiscus (S. ursulae (Riedel, 1938), S. simitiensis (Haas, 1960)), Toxancyloceras, and Imerites are present in the Barremian deposits. Patarroyo (2000aPatarroyo ( , 2000bPatarroyo ( , 2004) introduced interval zones to the Colombian Barremian deposits ( Figure 6) following the first appearance data of lower Barremian taxa, such as Psilotissotia colombiana, Nicklesia pulchella, and Pulchellia galeata, and upper Barremian taxa, such as Heinzia (Gerhardtia) veleziensis (actually Gerhardtia veleziensis, Figure 7) and Colchidites breistrofferi. However, some intervals in this succession include poor fossil recovery or there are no fossils at all. ...
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... some intervals in this succession include poor fossil recovery or there are no fossils at all. Thus, the upper part of the zones can be considered intrazones with respect to Pulchellia galeata, Gerhardtia veleziensis, and Colchidites breistrofferi ( Figure 6). However, directly above the Colchidites breistrofferi Zone, Kakabadze & Sharikadze (2004) suggested three biostratigraphical levels, the first is the succession with Pseudocrioceras anthulai (uppermost Barremian), the second with Procheloniceras albrechtiaustriae (lowest Aptian), and the third with Cheloniceras kiliani ( Figure 7), that are below the first Aptian assemblage zone of Etayo- Serna (1979). ...
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... Nicklesia pulchella Zone is present in both areas, but the range in Colombia is broader than that in the Mediterranean standard zone. The Kotetishvillia compressissima Standard Zone cannot be recognized in Colombia because of the absence of the index species; however, with the inclusion of the "Heinzia" communis Horizon ( Reboulet et al., 2014), it is possible to correlate it to the Colombian successions because of the presence of Pulchellia communis in the lower part of the Colombian Pulchellia galeata Zone ( Figure 6). The "Heinzia" caicedi Horizon of the Moutoniceras moutonianum Standard Zone ( Reboulet et al., 2014) can be correlated to Colombia because of the existence of "Pulchellia" caicedi (Karsten, 1858), which, until now, did not have a defined stratigraphic position in the Villa de Leyva area (Patarroyo, 2000b(Patarroyo, , 2004). ...
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The base of the Guadalupe Group, in the Tunja area of Colombia, contains cherts, porcellanites, mudstones, and siltstones with subordinate quartz arenites. The lithostratigraphic description of two stratigraphic sections showed that the dominant facies have fine granular textures and siliceous compositions, which considerably differ from those of t...
Citations
... These fossils include a large number of marine reptiles, such as plesiosaurs (Welles, 1962;Páramo-Fonseca et al., 2019), pliosaurs (Páramo-Fonseca et al., 2016, 2018Gómez-Pérez and Noè, 2017;Noè and Gómez-Pérez, 2022;), ichthyosaurs (Páramo-Fonseca, 1997;Maxwell et al., 2016;Páramo-Fonseca et al., 2020;Cortés et al., 2021), turtles (Cadena, 2015;Cadena and Parham, 2015;Cadena et al., 2019), crocodylomorphs (Cortés et al., 2019), and dinosaurs (Carballido et al., 2015;Cortés et al., 2023). Marine invertebrates are also widespread in the sedimentary sequence, particularly ammonoids (Etayo-Serna, 1968, 1979Patarroyo, 2000Patarroyo, , 2020 and orithopsid crabs (Luque et al., 2020). ...
Correctly identifying fossil specimens from parautochtonous deposits where marine and terrestrial organisms co-occur can be challenging due to the abundance of rare and obscure specimens with unclear morphologies. In this study, we reviewed fossils from the Lower Cretaceous La Paja Formation (Ricaurte Alto, Villa de Leyva, Colombia) that were originally described as the plant "Sphenophyllum colombianum" based on an apparent resemblance to the upper Paleozoic genus. We determined that the type specimen corresponds to the carapace of a hatchling turtle. In addition, a second specimen of "S. colombianum" although less well-preserved, also exhibits similar features of a hatchling turtle. The two fossil specimens are significant as they represent the first report of hatchling marine turtles from the Aptian of northwestern South Amer-ica and provide evidence of the exceptional preservation of the Marine Reptile Lager-stätte of Ricaurte Alto.
... We followed the stratigraphy of the Arcillolitas abigarradas Member described by Etayo-Serna (1968a) in Villa de Leiva as a reference to correlate our stratigraphic columns and, focused on correlating the stratigraphic provenance of the selected specimens with the stratigraphic segments established by this author. Using the ammonoid biozones established for Colombia (Bürgl, 1956a;Etayo-Serna, 1979;Patarroyo, 2000;Patarroyo, 2020) we correlated the specimens in which accurate information on their geographical origin is unknown but associated ammonoids were found. ...
... Recently Montoya Arenas (2019) described the Paja Formation in the type section and used the name initially utilized by Wheeler "La Paja" Formation. Here we employ the name Paja Formation which was used by Etayo-Serna (1968a) in his stratigraphic description of the Villa de Leiva region and later coined by many authors (Cadena and Parham, 2015;Cadena et al., 2019;Carrillo-Briceño et al., 2019;Cortés et al., 2019;Hoedemaeker, 2004;Noè and Gómez-Pérez, 2020;2022;Patarroyo, 2000;2020; among many others). ...
... veleziensis Hyatt, 1903 was identified (MPR-140414-2) (see Supplemental Data 3, fig. 3), which indicates the middle Barremian (sensu Bürgl, 1956a) or lower upper Barremian (sensu Patarroyo, 2000;2020). In this way, segment I can be correlated with segments A, B, and part of segment C of Etayo-Serna (1968a) ( Fig. 2A). ...
The Villa de Leiva – Sáchica - Sutamarchán region is the most prolific locality for Early Cretaceous marine vertebrates in Colombia and one of the richest in these vertebrates in the world. All of these vertebrates come from beds of
the Barremian-Aptian Arcillolitas abigarradas Member of the Paja Formation. Although many of the specimens have
already been taxonomically studied, no publications have discussed their stratigraphic position and distribution within the Barremian-Aptian interval. Herein, we provide, for the first time, detailed stratigraphic information for the
majority of the Barremian-Aptian marine vertebrates of the Villa de Leiva – Sáchica - Sutamarchán region reported so
far. Based on 10 stratigraphic sections described in the several specimens finding sites, together with biostratigraphic
information associated with specimens of imprecise geographical origin, we determined the stratigraphic provenance
of 26 marine vertebrate specimens. We also refined the stratigraphic provenance of some specimens including
the holotypes of Muiscasaurus catheti, “Kyhytysuka” sachicarum, and Protolamna ricaurtei whose stratigraphic origin
was not previously specified beyond the Arcillolitas abigarradas Member. The data obtained allowed us to identify four
vertebrate assemblages representing coeval faunas within the Barremian-Aptian interval, two from the Barremian and
two from the upper Aptian.
... The upper contact is concordant and net from the Tablazo Formation. The estimated thickness is 850 m, and the stratigraphic range is within the Hauterivian to the Aptian (Etayo Serna, 1968 a and b;Patarroyo, 2020). ...
La cartografía geológica detallada, los levantamientos estratigráficos, la recolección de fósiles y el muestreo de roca para análisis geoquímicos fueron las herramientas utilizadas para reconocer las unidades litoestratigráficas y precisar los niveles de mayor in- terés de fosfatos en la región axial de la cordillera Oriental, en los alrededores de Tunja (Boyacá).
Rocas sedimentarias con un rango estratigráfico situado entre el Cretácico y el Paleógeno representan esta parte de la cordillera Oriental, en algunos sectores cubiertas discordantemente por depósitos del Neógeno y el Cuaternario. Las unidades litoestratigrá- ficas de interés en fosfatos corresponden a la Formación Arenisca Dura y facies fino-granulares silíceas equivalentes, y las supra- yacentes formaciones Plaeners y Arenisca de Labor y Tierna pertenecientes al Grupo Guadalupe.
Las fallas inversas con dirección preferencial NE-SW y vergencia tanto al SE como al NW, algunas con salto transcurrente (fa- llas de Chivatá, Cormenchoque, Puente Hamaca, Viracachá, Soapaga, Machetá, Río Icabuco y Hermitaño) y pliegues de carácter regional (sinclinales de Tunja, Cómbita y Úmbita) y local, igualmente orientados al NE-SW, son las estructuras dominantes en el área de estudio.
El análisis geoestadístico de los datos geoquímicos de fluorescencia de rayos X (FRX) realizado a 299 muestras de roca de las unidades de interés para determinar fosfatos, del Grupo Guadalupe, permitió definir cuatro sectores con potencial mineral alto a medio de P2O5: 1) zona de Turmequé, Nuevo Colón y Tibaná, con 10,8-27,5 %; 2) zona de Ciénega y Viracachá, con 6,74-10,8 %;
3) zona de Samacá y Cucaita, con 6,74-17,3 %, y 4) zona de Toca y Tuta, con 6,74-17,3 %.
... Systematic flora and microflora studies are limited, despite the dominance of ferns and gymnosperms on the mainland and a few angiosperms (Jaramillo, 2019). In contrast, the influence of the sea led to paleontological studies of marine macrofossils in areas of the current Magdalena Valley and Eastern Cordillera (Etayo-Serna, 1964;Etayo-Serna, 1979;Gómez-Tapias et al., 2015;Patarroyo, 2020). ...
Palynology is an important tool for establishing age and interpreting paleoenvironments in both continental and marine deposits. This paper provides a summarized overview of the palynological information published for deposits in Colombia ranging from the Paleozoic to the Miocene-Pliocene. We found 111 publications in indexed journals contain palynological data from 511 sections or wells. Palynology of the Paleozoic in Colombia has been mainly studied in the Eastern Llanos; the Triassic-Jurassic is virtually unknown; there are studies on the Cretaceous in the Eastern Cordillera, the Upper Magdalena Valley, and Catatumbo; the Paleogene has been studied in sedimentary rocks of the Llanos foothills, the Eastern Cordillera, the Middle Magdalena Valley, Catatumbo, and in some isolated spots in La Guajira and the Caribbean while the Neogene has been studied in the Amazon, the Eastern Cordillera, and the Llanos foothills. Recent publications for the Caribbean and Pacific regions and a palynological zonation for the Llanos and its basins have been successfully used in other basins in the country. In recent years, the interest of the Colombian government in exploring new areas for hydrocarbon exploration in the Caribbean facilitated a partnership between the National Hydrocarbons Agency and the University of Caldas to conduct palynological studies in deposits ranging from the Late Cretaceous to the Quaternary. Here we present a summary of the main advances in Caribbean palynology.
... described the Barremian and Aptian deposits and fossils. Based on ammonites, other mollusks and echinoderms, Renz (1956Renz ( , 1960, Bürgl (1960), Rollins (1960Rollins ( , 1965, Patarroyo (2020) and Patarroyo and Götz (2020) recognized the existence of calcareous deposits of the Lower Cretaceous in the Alta Guajira. ...
... Salazar (2010) investigated the Palanz Formation, which involves continental and transitional deposits. Patarroyo (2020) and Patarroyo and Götz (2020) Thus, the present contribution seeks to provide data on the lithostratigraphy, nomenclature and biostratigraphy of the Yuruma Formation in its type locality, as well as nearby outcrops located to the north in Punta Espada (Uribia, La Guajira-Colombia). ...
... Since mid-2009, based on personal research carried out in the Punta Espada area, the Cretaceous deposits and marine fossils of the Alta Guajira (Patarroyo, 2011(Patarroyo, , 2020Patarroyo and Götz, 2013, 2014, 2020 have been recognized from field trips by the Department of Geosciences at the Universidad Nacional de Colombia in Bogotá. Later, between the end of February and the beginning of March 2018, under the auspices of the Servicio Geológico Colombiano, the Yuruma hill ( Figure 2) was surveyed to advance the work related to the book of The Geology of Colombia (Patarroyo, 2020). ...
The Yuruma Formation in the Yuruma hill area its type locality can be differentiated into two stratigraphic intervals. The lower
and upper intervals of the Yuruma Formation can also be subdivided into two segments. The lithological, sedimentological and
fossiliferous characteristics support this differentiation, which allows to interpret the accumulation energy influences over the sea
floor. The lower interval is characterized by intercalations of very fossiliferous marlstones and biomicrites with benthonic and
nektonic fossils from the lower Barremian. The upper interval is represented by marlstones and biomicrites with poor benthonic
and nektonic fossils from the upper Barremian and probably from the lower Aptian. In the Punta Espada area, whit scarce lithological
controls over the lower and upper parts of the Yuruma Formation, were found biomicrites with benthonic and nektonic
fossils of the lower Barremian to the lower part, and to the top were recognized biomicrites that underlie beds with lower Aptian
ammonites.
... The Lower Cretaceous carbonate platforms in Colombia characterized by abundance in the fossil content. The presence of ammonoids as Niklesia sp. as a key fossil allowed to delimit the studied stratigraphic section as Barremian deposits being coherent with the occurrence of other taxa as Echinoidea, Bivalvia and Gastropoda (Figure 9; Patarroyo, 2020). The paleogeographic distribution of the Paja, Ritoque, Rosablanca, Fomeque, Macanal, Juntas and the Upper Tibasosa formations provide tools to understand the lithologic changes associated with variations in bathymetry, sea-level rise, geological time, carbonate supply, and tectonics explaining why towards the west are frequent muddy siliciclastic rocks with abundant planktonic organisms while in the east exists more infaunal and epifaunal individuals (Patarroyo, 2020). ...
... The presence of ammonoids as Niklesia sp. as a key fossil allowed to delimit the studied stratigraphic section as Barremian deposits being coherent with the occurrence of other taxa as Echinoidea, Bivalvia and Gastropoda (Figure 9; Patarroyo, 2020). The paleogeographic distribution of the Paja, Ritoque, Rosablanca, Fomeque, Macanal, Juntas and the Upper Tibasosa formations provide tools to understand the lithologic changes associated with variations in bathymetry, sea-level rise, geological time, carbonate supply, and tectonics explaining why towards the west are frequent muddy siliciclastic rocks with abundant planktonic organisms while in the east exists more infaunal and epifaunal individuals (Patarroyo, 2020). The occurrence of worldwide carbonate platforms during the Lower Cretaceous implies that variations in the eustatic sea-level controlled the deposition of marine sediments, representing an important transgressive surface as occurs in Asia (e.g., Bachmann and Hirsch, 2006), Europe (e.g., Hoedemaeker and Herngreen, 2003), Africa (e.g., Reyment and Dingle, 1987), and America (e.g., Barragán and Melinte, 2006;Patarroyo, 2020); recording similar depositional systems and fossil content to the Upper Tibasosa Formation. ...
... The paleogeographic distribution of the Paja, Ritoque, Rosablanca, Fomeque, Macanal, Juntas and the Upper Tibasosa formations provide tools to understand the lithologic changes associated with variations in bathymetry, sea-level rise, geological time, carbonate supply, and tectonics explaining why towards the west are frequent muddy siliciclastic rocks with abundant planktonic organisms while in the east exists more infaunal and epifaunal individuals (Patarroyo, 2020). The occurrence of worldwide carbonate platforms during the Lower Cretaceous implies that variations in the eustatic sea-level controlled the deposition of marine sediments, representing an important transgressive surface as occurs in Asia (e.g., Bachmann and Hirsch, 2006), Europe (e.g., Hoedemaeker and Herngreen, 2003), Africa (e.g., Reyment and Dingle, 1987), and America (e.g., Barragán and Melinte, 2006;Patarroyo, 2020); recording similar depositional systems and fossil content to the Upper Tibasosa Formation. ...
The Tibasosa Formation is the main source of limestones in Boyacá. This unit corresponds to a Valanginian-Albian age according to the fossil content in the Eastern Cordillera Basin, recording the first incursion of the Cretaceous sea in Firavitoba. Outcrop-based facies and stratigraphic analyzes of the ~12 m-thick siliciclastic-carbonate succession of the uppermost Tibasosa Formation indicate tidal and carbonate systems. Ten facies/microfacies are grouped into two facies associations (FAs): FA1, tidal flat deposits consist of laminated sandstones/siltstones and floatstones with a single organism dominance (bivalve shells); and FA2 comprises fossiliferous rudstones, floatstones, packstones, and wackstones, representing a carbonate platform. The petrographic description determined rock textures/genesis and the diagenetic sequence with features of the eodiagenesis, mesodiagenesis, and telodiagenesis suggesting a primary origin of these carbonates. The analysis using cathodoluminescence (CL), energy disperse spectrometry (EDS), and scanning electron microscopy (SEM) allowed identify compositional differences, cementation phases, and morphological features in different processes as micritization, neomorphism, porosity, pyritization, compaction, cementation, fracturing, and weathering. The interpretation of facies and microfacies indicated a deposition mainly in a shallow platform with variation in the hydraulic conditions, warm waters, and episodic events of storms/tsunamis that fragmented the bioclasts. A shallow marine system in the Eastern Cordillera Basin during Cretaceous indicates a large transgressive event that flooded hundreds of kilometers, being a link with the Pacific Ocean before the Andes uplift. The main diagenetic events correspond to micritization, cementation of calcite, and mechanical/chemical compaction as a result of microbial activity, dissolution, precipitation in the vadose/phreatic zone, and burial diagenesis. The diagenetic sequence events reveal the incidence of marine and meteoric process that reduced porosity and attest to the microbial activity in carbonate precipitated. This new interpretation allows the understanding of carbonate platforms in the Eastern Cordillera Basin for future correlations of the Cretaceous sea in Colombia. Resumen La Formación Tibasosa es la principal fuente de calizas en Boyacá. Esta unidad se depositó entre el Valanginiano-Albiano según el contenido fósil en la Cuenca Cordillera Oriental, registrando la primera incursión del mar Cretácico en Firavitoba. Los análisis de facies y estratigráficos de una sucesión carbonática-siliciclástica de ~12 m de espesor de la Formación Tibasosa Superior indican sistemas mareales/carbonáticos. Diez facies/microfacies se agruparon en dos asociaciones de facies (AFs): AF1, planicie mareal consiste en areniscas/limolitas laminadas y floatstones con un solo tipo de organismo dominante (conchas de bivalvos); y AF2 comprende rudstones, floatstones, packstones y wackstones, representando una plataforma carbonática. La descripción petrográfica determinó la textura/génesis y la secuencia diagenética con características de la eodiagénesis, mesodiagénesis y telodiagénesis sugiriendo un origen primario de estos carbonatos. El análisis mediante catodoluminiscencia (CL), espectrometría de energía dispersa (EDS) y microscopía electrónica de barrido (MEB) permitió identificar diferencias composicionales, fases de cementación y características morfológicas en diferentes procesos como micritización, neomorfismo, porosidad, piritización, compactación, cementación, fracturamiento. y meteorización. La interpretación de facies/microfacies indicó una deposición en una plataforma poco profunda con condiciones hidráulicas fluctuantes, aguas cálidas y eventos de tormentas/tsunamis que fragmentaron los bioclastos. Este sistema deposicional en la Cuenca Cordillera Oriental durante el Cretácico indica un gran evento transgresivo que inundó cientos de kilómetros, revelando conexión con el Océano Pacífico antes del levantamiento Andino. Los principales eventos diagenéticos corresponden a la micritización, cementación de calcita y compactación mecánica/química como resultado de la actividad microbiana, disolución, precipitación en la zona vadosa/freática y diagénesis de enterramiento. La secuencia diagenética revela la incidencia de procesos marinos y meteóricos que redujeron la porosidad y corroboran la actividad microbiana en el carbonato precipitado. Esta nueva interpretación permite comprender las plataformas carbonatadas en la Cuenca Cordillera Oriental para futuras correlaciones del mar Cretácico en Colombia.
... De tal suerte, con posición estratigráfica fue posible recolectar amonitas y rudistas del Aptiano en la misma localidad. Además, en sectores aledaños, se encontraron depósitos y fósiles del Barremiano, Albiano y Cenomaniano (Patarroyo, 2011(Patarroyo, , 2020. ...
... En el camino entre el asentamiento de Punta Espada y Párauinkrein o Parabanclen es posible encontrar una sucesión que incluye depósitos del Barremiano, Aptiano, Albiano, Cenomaniano y Turoniano (Patarroyo, 2011(Patarroyo, , 2020Patarroyo y Götz, 2013, 2014 Rollins (1960Rollins ( , 1965, en donde se reconocen micritas grises y negras, biomicritas en capas gruesas y muy gruesas (Figura 5). Luego, estratigráficamente arriba y a la base de la Formación "Cogollo" (Figura 3, Figura 5) siguiendo a Rollins (1960Rollins ( , 1965, continúan intercalaciones de lodolitas calcáreas negras con capas medias a gruesas de micritas y biomicritas (lugar 1 de colecta en Figura 1C y esquema geológico Figura 2, Figura 4B), como indicaron Renz (1960) y Bürgl (1960. ...
Resumen
En depósitos del valle Piedra del Destino (Punta Espada, Uribia – La Guajira, Colombia) se presentan biomicritas, bioesparitas y lodolitas calcáreas, en las que se encontraron Dufrenoyia sp., D. cf. hansbuergli, Cheloniceras sp., Pseudohaploceras cf. liptoviense y Amphitriscoelus waringi con un rango estratigráfico del Aptiano inferior. La literatura refiere que dichos depósitos hacen parte de la Formación Cogollo, pero con base en el análisis de la litoestratigrafía, la fauna fósil, la tectónica y la continuidad de los cuerpos de roca, difícilmente se recomienda aplicar la nomenclatura litoestratigráfica del occidente de Venezuela para la Alta Guajira, región que involucra los depósitos cretácicos de Punta Espada. La fauna encontrada muestra influencia tanto del mar del Tetis como
del entorno regional por provincialismo.
Abstract
In the Piedra del Destino valley (Punta Espada, Uribia – La Guajira, Colombia) there are biomicrites, biosparites and calcareous shales that contain Dufrenoyia sp., D. cf. hansbuergli, Cheloniceras sp., Pseudohaploceras cf. liptoviense and Amphitriscoelus waringi with a lower Aptian range. The bibliography relate that those deposits are part of the Cogollo Formation, but taken into account the lithostratigraphical analysis, fossil fauna, tectonic and body rock continuity, it is not recommendable to apply the lithostratigraphical nomenclature from western Venezuela to the Alta Guajira region where are evolved the Punta Espada Cretaceous deposits. The collected fossils show both influence of the Tethys domain and as regional provincialism.
... The discovery of a South American teleosauroid suggests that at least one lineage of this diverse clade survived the Jurassic/ Cretaceous extinction event recognized by Raup and Sepkoski (1986), which resulted in major faunal turnover in both marine and terrestrial realms that affected aquatic groups like crocodylomorphs (Tennant et al., 2016(Tennant et al., , 2017; but see Jouve et al., 2017). Ammonite biostratigraphy in the Paja Formation sedimentary sequence (e.g., Etayo-Serna, 1968;Patarroyo, 2000Patarroyo, , 2004Patarroyo, , 2019 allows the stratigraphic provenance of CIP-0001 to be confidently assessed as upper Barremian (ca. 120 Ma). ...
Teleosauroid extinction at the Jurassic/Cretaceous boundary has been hypothesized to be an artifact of sampling only temperate paleolatitudes. Here, we describe the definitive youngest record of Teleosauroidea, from the upper Barremian of the paleotropics. The preserved material consists of dorsal vertebrae, dorsal ribs, dorsal and ventral osteoderms, and epipodial remains. We refer the specimen to Teleosauroidea based on the large hourglass-shaped amphiplatyan morphology of the dorsal centra and rectangular dorsal osteoderms, which are much wider than long and have a straight anterior edge. The South American specimen is one of the largest known teleosauroids, with an estimated body length of 9.6 m. This is the first evidence of a marine crocodylomorph recorded from the Paja Formation of Colombia. The survival of Teleosauroidea in the paleotropics of northern Gondwana following the group’s extinction in Europe supports the hypothesis that water temperature played a role in controlling the diversity and distribution of these large marine predators
The Mesozoic Marine Revolution restructured the world’s ocean biodiversity into the complex marine ecosystems of today. This revolution began during the Triassic but the origin of this complexity is poorly understood due to a lack of detailed ecosystem reconstructions throughout time. We present the first site-specific ecological network for a marine Mesozoic fauna based on the Early Cretaceous Paja Formation biota of Colombia that preserves numerous, large-bodied, predatory marine reptiles. The trophic food-web was quantitatively reconstructed based on inferred trophic interactions of marine producers, consumers, and large apex predators. Compared to well-studied Caribbean reef ecosystem networks, the Paja biota network is missing a great proportion of benthic invertebrates and fishes, despite its rich higher trophic levels. We hypothesize that the ammonites from the Paja biota either mirrored the diversity represented by some fishes today or established a novel trophic unit with no living analogue. Recalibrating the Paja biota network to trophic analogues in the Caribbean, such as sea turtles, estimates that the largest Paja marine reptile hyper-apex predators occupied trophic levels a full tier higher than any extant marine apex predator. The Paja biota network is a starting point to tracing the evolution of marine ecosystems across the Mesozoic Marine Revolution.
A recently prepared fragment of the anterior end of a snout comprising occluded upper and lower jaws of a juvenile individual of Stenorhynchosaurus munozi Páramo-Fonseca et al., 2016 (Plesiosauria, Pliosauridae) is described herein. The specimen was found in the 1990s at Sutamarchán (Boyacá, Colombia), in Barremian beds of the Arcillolitas abigarradas Member of the Paja Formation. Its description provides hitherto unknown valuable morphological information on the species: dorsal anterior extension of the vomer, five premaxillary teeth (not four as was previously suggested), and anteriorly directed orientation of the first premaxillary alveolus (procumbent). New observations made on previously studied material corroborated the existence of procumbent anterior premaxillary teeth in the species. The presence of this trait highlights the close relationship of S. munozi with other early-diverging brachauchenines from the Lower Cretaceous of Russia.
