A well preserved skeleton of the fossil shark Cosmopolitodus hastalis from the late Miocene of Peru, featuring fish remains as fossilized stomach contents

Both the preservation of the poorly mineralized skeleton of sharks and the preservation of stomach contents are rarely observed in the fossil record. Here we report on a partial skeleton of a lamniform shark, including portions of the visceral arches and the anterior segment of the vertebral column, collected from the late Miocene beds of the Pisco Formation exposed at Cerro Yesera (Ica Desert, South Peru). Based on the morphology of the preserved teeth, this specimen was determined as a juvenile of the extinct lamnid species Cosmopolitodus hastalis. The shark skeleton includes remains of fish (featuring a pilchard determined as Sardinops sp. cf. S. sagax) in the abdominal region. These fish remains are interpreted herein as the fossilized stomach contents of the shark. For the first time, piscivory is demonstrated in a juvenile individual of Cosmopolitodus hastalis. This result is consistent with the current knowledge about the feeding habits of immature individuals of extant lamniform shark species (including Carcharodon carcharias and Isurus oxyrinchus). Our report further outlines the fundamental role of schooling pilchards in the late Miocene trophic chains of the highly productive coastal waters off present South Peru. Moreover, the find of this well preserved shark skeleton strengthens the qualification of the Pisco Formation as a Fossil-Lagerstätte, and emphasizes the role of early mineralization processes in cases of exceptional preservation

A rhinopristiform sawfish (Genus pristis) from the middle eocene (lutetian) of southern Peru and its regional implications

Modern sawfishes (Rhinopristiformes: Pristidae) are circumglobally distributed in warm waters and are common in proximal marine and even freshwater habitats. The fossil record of modern pristid genera (i.e., Pristis and Anoxypristis) dates back to the early Eocene and is mostly represented by isolated rostral spines and oral teeth, with phosphatised rostra representing exceptional occurrences. Here, we report on a partial pristid rostrum, exhibiting several articulated rostral spines, from middle Eocene strata of the Paracas Formation (Yumaque Member) exposed in the southern Peruvian East Pisco Basin. This finely preserved specimen shows anatomical structures that are unlikely to leave a fossil record, e.g., the paracentral grooves that extend along the ventral surface of the rostrum. Based on the morphology of the rostral spines, this fossil sawfish is here identified as belonging to Pristis. To our knowledge, this discovery represents the geologically oldest known occurrence of Pristidae from the Pacific Coast of South America. Although the fossil record of pristids from the East Pisco Basin spans from the middle Eocene to the late Miocene, sawfishes are no longer present in the modern cool, upwelling-influenced coastal waters of southern Peru. Given the ecological preferences of the extant members of Pristis, the occurrence of this genus in the Paracas deposits suggests that middle Eocene nearshore waters in southern Peru were warmer than today. The eventual disappearance of pristids from the coastal waters off southern Peru might be interpreted as reflecting the late Cenozoic trend of strengthening of the Humboldt Current

A new species of Macropredator Dolphin (Cetacea: Kentriodontidae) from middle Miocene, Pisco formation, South coast of Perú

Kentriodontidae is a family of fossil delphinidan dolphins with historically debatable monophyly, but the situation has changed in the last few years. Their fossil record is extensive, from the late Oligocene to the late Miocene (23.3-9 Ma), and shows greater diversity during the Miocene in Europe, Asia, America, and Oceania. This family is composed of two subgroups according to the last phylogenetic analysis, being this second group composed of the largest known Kentriodontidae: Hadrodelphis, Liolithax, Lophocetus, and Macrokentriodon. Three previous kentriodontid dolphins were described and the present authors have formerly reported two large kentriodontids, all from the Pisco formation, Ica region, Peru. The Pisco Formation (Middle Miocene-Pliocene) presents lithology composed of whitish silty claystones, diatomaceous lutites, diatomites, some intercalations of a few compact fine sandstones, and tuffaceous gravels with a neritic sedimentary environment attributed to the inner platform. The present specimen of Kentriodontidae sp. indet. (MUSM 4268) was previously reported in an abstract of 2018 without a detailed description. We are now describing in detail MUSM 4268, which comes from the P0 Sequence of Pisco formation (middle Miocene age) from Cerro Yesera de Amara located 25 km Southwestern from Ocucaje city, Ica region, southern coast of Peru. MUSM 4268 is composed of one partial skull with mandibles, periotic and fragmentary tympanic bulla, this skull (condylobasal length: 679mm; bizygomatic width: 252 mm) compared with other large species of the second group of Kentriodontidae display transversally narrow nasals differing from Lophocetus, frontals exposed at the vertex, wide temporal fossa and convex anterodorsal margin of the supraoccipital as seen in Lophocetus, Hadrodelphis, and Liolithax. However, the presence of transversally narrow nasals along their entire length, low vertex, and robust rostrum morphology resembles Liolithax pappus but differs from this taxa by having slightly elongated and narrow antorbital processes and wide antorbital notches. Also, it presents powerful mandibles with robust teeth, premaxillae laterally inflated slightly anterior to level of antorbital notches and periotic with higher pars cochlearis, similar to L. pappus. Considering these cranial characters, MUSM 4268 probably represents a new species related to L. pappus or a related new genus. MUSM 4268 probably was a macro-predator kentriodontid dolphin from Pisco Formation (middle Miocene) and represents the third record of large kentriodontids for South America. Previous records include a kentriodontid probably related to Macrokentriodon also from the Pisco Formation (Late Miocene), Peru, and a kentriodontid probably related to Hadrodelphis from the Caujarao Formation (middle-late Miocene), Venezuela

Los delfines «Lophocetinae» (Mammalia: Cetacea: Kentriodontidae) de la Formación Pisco de cerro Yesera de Amara, Ocucaje, Ica

La existencia de cetáceos fósiles en el Perú es conocida desde hace más de un siglo (Lisson, 1898), siendo el primer cetáceo descrito Incacetus broggi, un odontoceto de la familia Kentriodontidae proveniente de la hacienda Santa Rosa, Ica (Colbert, 1944); La fauna de cetáceos odontocetos de la Formación Pisco fue revisada por Muizon (1984, 1988a) y Pilleri (1989, 1990). La familia Kentriodontidae del Mioceno Medio a Tardío de la Formación Pisco, fue revisada por De Muizon (1988a), quien describió dos especies más de esta familia. El objetivo del presente trabajo es reportar dos probables nuevas especies de «Lophocetinae» (Kentriodontidae) de estratos del Mioceno mediotardío en Cerro Yesera Amara, localidad de Mal Paso, distrito de Ocucaje, provincia de Ica, región de Ica

Nuevo espécimen de Carcharodon hastalis (Lamniformes Lamnidae) en sedimentitas de la Formación Pisco: evidencias de su paleoecología trófica

En los últimos años, los registros de vertebrados fósiles con preservación excepcional expuestos en la cuenca Pisco, se han incrementado notablemente (Clarke et al., 2010; Lambert et al., 2010, 2015; Bianucci et al., 2010, 2014; Stucchi et al., 2016 entre otros) y los afloramientos de la Formación Pisco han puesto en evidencia no solo una amplia diversidad de taxones fósiles asociados sino además, una fosilización excepcional que la distingue de otras formaciones en diferentes latitudes. El presente trabajo, como producto de la actualización de la Carta Geológica Nacional, se suma a los hallazgos concernientes a los seláceos fósiles y amplia el registro nacional limitado mayormente a sus dientes. Para el presente caso, se pone en evidencia un esqueleto fósil parcial que conserva además de las mandíbulas y algunos dientes, los discos vertebrales articulados e incluso parte de lo que se infiere como su contenido estomacal consistente en sardinas fósiles (Sardinops sp.). El hallazgo fue realizado en el cerro Yesera en la margen izquierda del río Ica, al SO de la localidad de Callango, distrito de Ocucaje, departamento de Ica (Figura 1). Estratigráficamente corresponde a niveles de la Formación Pisco, y en tiempo correspondería a niveles del Mioceno superior (aprox. 9 Ma). La sistemática paleontológica utilizada sigue a lo propuesto por Ehret et al., (2012

New Miocene sulid birds from Peru and considerations on their Neogene fossil record in the Eastern Pacific Ocean

Boobies and gannets (family Sulidae) are the most specialized plunge divers among seabirds. Their fossil record along the Pacific coast of South America extends to the early Middle Miocene. Here we describe three new species of sulids: Sula brandi sp. nov., Sula figueroae sp. nov., and Ramphastosula aguirrei sp. nov., from the early Late Miocene of the Pisco Formation (Peru). Two of them are relatives of the living genus Sula, which represents medium and large-sized boobies. A new species of the extinct genus Ramphastosula is also described, adding to the discussion of possible alternative feeding strategies among sulids. The fossil record suggests that sympatric sulids exhibit different body sizes at least since the Oligocene epoch, a strategy related with resource partitioning. Furthermore, we find current analysis and knowledge of the fossil record unsuitable to evaluate properly seabird diversity changes through time

A WELL PRESERVED SKELETON OF THE FOSSIL SHARK <em>COSMOPOLITODUS HASTALIS</em> FROM THE LATE MIOCENE OF PERU, FEATURING FISH REMAINS AS FOSSILIZED STOMACH CONTENTS

Both the preservation of the poorly mineralized skeleton of sharks and the preservation of stomach contents are rarely observed in the fossil record. Here we report on a partial skeleton of a lamniform shark, including portions of the visceral arches and the anterior segment of the vertebral column, collected from the late Miocene beds of the Pisco Formation exposed at Cerro Yesera (Ica Desert, South Peru). Based on the morphology of the preserved teeth, this specimen was determined as a juvenile of the extinct lamnid species Cosmopolitodus hastalis. The shark skeleton includes remains of fish (featuring a pilchard determined as Sardinops sp. cf. S. sagax) in the abdominal region. These fish remains are interpreted herein as the fossilized stomach contents of the shark. For the first time, piscivory is demonstrated in a juvenile individual of Cosmopolitodus hastalis. This result is consistent with the current knowledge about the feeding habits of immature individuals of extant lamniform shark species (including Carcharodon carcharias and Isurus oxyrinchus). Our report further outlines the fundamental role of schooling pilchards in the late Miocene trophic chains of the highly productive coastal waters off present South Peru. Moreover, the find of this well preserved shark skeleton strengthens the qualification of the Pisco Formation as a Fossil-Lagerstätte, and emphasizes the role of early mineralization processes in cases of exceptional preservation

Nuevo espécimen de Carcharodon hastalis (Lamniformes, Lamnidae) en sedimentitas de la Cuenca Pisco: evidencias de su ecología trófica.

En los últimos años, los registros de vertebrados fósiles con preservación excepcional expuestos en la cuenca Pisco, se han incrementado notablemente y los afloramientos de la Formación Pisco han puesto en evidencia no solo una amplia diversidad de taxones fósiles asociados sino además, una fosilización excepcional que la distingue de otras formaciones en diferentes latitudes. El presente trabajo, como producto de la actualización de la Carta Geológica Nacional, se suma a los hallazgos concernientes a los seláceos fósiles y amplia el registro nacional limitado mayormente a sus dientes. Para el presenta caso, se pone en evidencia un esqueleto parcial que conserva además de las mandíbulas y algunos dientes, los discos vertebrales articulados e incluso parte de lo que se infiere como su contenido estomacal consistente en sardinas fósiles (Sardinops sp.). El hallazgo fue realizado en el cerro Yesera en la margen izquierda del río Ica, al SO de la localidad de Callango, distrito de Ocucaje, departamento de Ica. Estratigráficamente corresponde a niveles de la Formación Pisco, y en tiempo correspondería a niveles del Mioceno superior

Data from: No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the late Miocene of Peru

Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid–fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator–prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine (Sardinops sagax). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins

Lambert et al_suppl material

1. Supplementary Figures 2. Size and Weight Estimates for Messapicetus gregarius 3. Size and Weight Estimates for Sardinops sp. cf S. sagax 4. Comparison of Cervical Vertebrae Ankylosis and Size among Ziphiidae 5. Comparison of Relative Humeral Length among Ziphiidae 6. Abbreviations for Institutions 7. Supplementary Reference