The Cocinetas Basin is located on the eastern flank of the Guajira Peninsula, northern Colombia (southern Caribbean). During the late Oligocene through the Pliocene, much of the basin was submerged. The extensive deposits in this area suggest a transition from a shallow marine to a fluvio-deltaic system, with a rich record of invertebrate and vertebrate fauna. The elasmobranch assemblages of the early Miocene to the late Pliocene succession in the Cocinetas Basin (Jimol, Castilletes and Ware formations, as well as the Patsúa Valley) are described for the first time. The assemblages include at least 30 taxa of sharks (Squaliformes, Pristiophoriformes, Orectolobiformes, Lamniformes and Carcharhiniformes) and batoids (Rhinopristiformes and Myliobatiformes), of which 24 taxa are reported from the Colombian Neogene for the first time. Paleoecological interpretations are based on the feeding ecology and on estimates of the paleohydrology (relative salinity, temperature) using stable isotope compositions of oxygen in the bioapatite of shark teeth. The isotopic composition of the studied specimens corroborates paleoenvironmental settings for the studied units that were previously estimated based on the sedimentology and biology of the taxa. These Neogene elasmobranch assemblages from the Cocinetas Basin provide new insights into the diversity the sharks and rays inhabiting the coastal and estuarine environments of the northwestern margin of South America, both during the existence of the gateway between the Atlantic and Pacific oceans and following its closure.
During the Neogene, large areas of the northern margin of South America were
submerged (see
Location
Neogene marine chondrichthyan faunas from the southern proto-Caribbean
(especially from the northern margin of South America) are well known from
Venezuela and the Lesser Antilles (e.g.,
A taxonomic list is presented of the elasmobranch fauna collected in the
Cocinetas Basin (Figs.
The fossil elasmobranch assemblages (Table
The samples were collected by JDCB, AH and other collaborators during several expeditions between 2010 and 2014. Large specimens were surface collected and 50 kg of bulk sediment was collected, sieved and screen washed (mesh sizes: 0.5 and 2 mm) for subsequent picking of smaller specimens from the localities 290468 (Patsúa assemblage), 290632 and 390094 (Castilletes Formation).
The Cocinetas Basin elasmobranch specimens (File S4) are housed in the
paleontological collections of the Mapuka Museum of Universidad del Norte
(MUN), Barranquilla, Colombia. Nomenclature follows
Stratigraphy of the Cocinetas Basin.
Quantitative data includes percentages of specimens by order, family and
genus recorded in the overall assemblages of the Cocinetas Basin
(Table
Elasmobranchii paleodiversity of the Cocinetas Basin.
Analyses of
Shark teeth specimens used in geochemical investigation.
Continued.
The
Paleotemperatures from the
This formation is one of the most extensive Cenozoic units in the Cocinetas
Basin (Fig.
This lithostratigraphic unit crops out along the eastern margin of the
Cocinetas Basin (Fig.
Squaliformes, Pristiophoriformes, Orectolobiformes and Lamniformes
of the Cocinetas Basin.
Sediments of Bahía Cocinetas in the Patsúa Valley were previously
mapped as the Castilletes Formation
Lamniformes and Carcharhiniformes of the Cocinetas Basin.
The type section of the Ware Formation is located immediately east of the
village of Castilletes, and correlated deposits are distributed along the
eastern margin of the Cocinetas Basin (Fig.
Carcharhiniformes of the Cocinetas Basin.
The taxonomic composition of the 36 fossiliferous localities (Table S1)
includes at least 30 taxa of squalomorphs, galeomorphs and batoids
(Table Squaliformes Pristiophoriformes Orectolobiformes Lamniformes Carcharhiniformes Rhinopristiformes Last, Séret and Naylor, Myliobatiformes
Carcharhiniformes of the Cocinetas Basin.
Rhinopristiformes and Myliobatiformes of the Cocinetas Basin.
Myliobatiformes of the Cocinetas Basin.
Although extant representatives of the fossil elasmobranchs present in the
Cocinetas assemblage exhibit a wide range of diets, four feeding preferences
of benthic–pelagic predators and filter feeders can be recognized
(Table S3). For the Jimol Formation, piscivorous feeders are the most diverse
group (Fig.
Elasmobranch paleodiversity (orders) of the Cocinetas Basin.
Dietary preferences of the elasmobranch paleofauna from the Cocinetas Basin.
The
Stratigraphic distribution of the
Results from sharks of the Patsúa assemblage are mainly discussed in
terms of paleoecology, since the age of the assemblage is unknown. The
average isotope compositions from the two stratigraphically uncertain
Patsúa layers are very similar (localities 290468 and 290472;
In the Castilletes Formation, the mean
In the youngest unit of the Ware Formation, low
From the older Jimol Formation only two teeth were analyzed, but their
average is indistinguishable from that of the overall average value of both
the Castilletes and Patsúa assemblages. When the Patsúa, Castilletes
and Ware assemblages are compared on a box plot, the averages of the first two
are indistinguishable (Fig.
Of the elasmobranch assemblages described here from the Cocinetas Basin
(
The elasmobranch fauna of the Cocinetas assemblages shows a clear
differentiation in paleodiversity between geological units (see Fig. S5). The
Castilletes Formation and Patsúa assemblage are the most diverse units of
all the assemblages from the Cocinetas Basin (Tables S1–S2, Fig. S5). In
contrast, the Jimol and Ware formations are the least diverse units
(Tables S1–S2, Fig. S5). These paleodiversity differences between the
geological units of the Cocinetas Basin could be attributed to (1) less
intensive sampling, especially less systematic sieving of all studied
localities (see Sect.
Of biostratigraphic significance to the elasmobranch fauna of the Cocinetas
assemblages is the record of
With reference to
The Neogene sedimentary sequence of the Cocinetas Basin has been
characterized by a transition from a shallow marine to a fluvio-deltaic
paleoenvironment
In contrast with the diverse early–middle-Miocene elasmobranch assemblages
of the Jimol and Castilletes formations and the Patsúa assemblage, the
fauna of the late Pliocene Ware Formation is low in diversity and abundance
(Figs.
The
Nonetheless, shark tooth Patsúa assemblage. The age of this fauna is not as well
established as it is for the other sites; therefore the obtained isotopic
values represent paleoenvironmental conditions somewhere within the
Burdigalian and Langhian periods. These shark teeth had predominantly marine
isotopic compositions with one low Castilletes Formation. The sedimentary sequence of the
Cocinetas Basin is described as a transition from a shallow marine to a
fluvio-deltaic paleoenvironment (i.e., a regression). Similar to the results
from the Patsúa assemblage, the Ware Formation. The isotope data are significantly different
for the Ware Formation from the Patsúa assemblage and the Castilletes
Formation (except for locality 390093, Fig.
A diverse elasmobranch fauna containing 30 taxa of sharks and rays was
identified, with the most diverse groups being Carcharhiniformes and
Lamniformes, respectively. The fossil assemblage seems to agree with
paleoenvironmental descriptions from previous studies for the fossiliferous
formations of the Cocinetas Basin (Jimol, Castilletes and Ware). An elasmobranch assemblage (Patsúa fauna) is reported from
undifferentiated facies of the Jimol and Castilletes formations and
represents a subtidal marine environment with limited freshwater influence. The biogenic phosphate A predominant brackish-like More samples and additional proxies are recommended to refine our
interpretations. Nevertheless, this multidisciplinary study certainly
complements the knowledge about the paleoenvironmental context and evolution
of tropical America.
The raw isotopic data and corrections can be found in
The supplement related to this article is available online at:
The conceptualization was carried out by JDCB and AH. Data curation, formal analysis and investigation were performed by JCDB and ZL. Funding acquisition was supported by JDCB, AH and TV. Methodology was set by JCDB and ZL with contributions from all co-authors. Resources were provided by JCDB, AH and TV. Supervision was provided by AH, TV and OA. Validation was discussed with LK, TV and OA. Visualization was done by JDCB, ZL and LK. The writing of the original draft was performed by JDCB and ZL with contributions from all co-authors, and the review and editing was done by ZL with substantial contributions from all co-authors.
The authors declare that they have no conflict of interest.
This work was supported by the Swiss National Science Foundation (SNF 31003A-149605 to MRSV, SNF 200020-160055/1 to Zoneibe Luz and Torsten Vennemann) and by the Smithsonian Tropical Research Institute (National Geographic Society, Anders Foundation, Gregory D. and Jennifer Walston Johnson, 1923 Fund, Universidad del Norte and National Science Foundation EAR 0957679 to Carlos Jaramillo). The authors wish to especially thank to Henri Cappetta, Sylvain Adnet, Loic Costeur, Rene Kindlimann, Gustavo Ballen and the Wayuu communities of the Alta Guajira for their generous and important counseling, permission for collection revision and collaboration. Participants of fieldwork in Alta Guajira (2009–2014) are thanked for their assistance in collection of samples. Special thanks to the Center for Microscopy and Image Analysis of the University of Zurich for their assistance and support performing the scanning electron microscopy analysis. Zoneibe Luz would like to thank Thiago Nascimento for all technical assistance to build the manuscript file. We are thankful to the Alcaldía Bolivariana de Urumaco; the Universidad Experimental Francisco de Miranda; the Mapuka Museum of the Universidad del Norte (Barranquilla, Colombia); the Natural History Museum of Basel (Switzerland); the paleontological collection of the Institut des Sciences de l'Evolution, University of Montpellier (France); and the Palaeontological Institute and Museum at the University of Zurich for their valuable assistance and for access to comparative material. Authors are thankful to Dana Ehret and the anonymous reviewer for the contributions to improve the manuscript and to Alberto Collareta for his support of our research. Last but not least, thanks to the Editor David Gillikin for the manuscript handling.Edited by: David Gillikin Reviewed by: Dana Ehret and one anonymous referee