Multi‐proxy analyses of Late Cretaceous coprolites from Germany

A total of 462 coprolites from three localities exposing Upper Cretaceous deposits in the Münster Basin, northwestern Germany, have been subjected to an array of analytical techniques, with the aim of elucidating ancient trophic structures and predator–prey interactions. The phosphatic composition, frequent bone inclusions, size and morphology collectively suggest that most, if not all, coprolites were produced by carnivorous (predatory or scavenging) vertebrates. The bone inclusions further indicate that the coprolite producers preyed principally upon fish. Putative host animals include bony fish, sharks and marine reptiles – all of which have been previously recorded from the Münster Basin. The presence of borings and other traces on several coprolites implies handling by coprophagous organisms. Remains of epibionts are also common, most of which have been identified as the encrusting bivalve Atreta. Palynological analyses of both the coprolites and host rocks reveal a sparse assemblage dominated by typical Late Cretaceous dinoflagellates, and with sub‐ordinate fern spores, conifer pollen grains and angiosperm pollen grains. The dinoflagellate key taxon Exochosphaeridium cenomaniense corroborates a Cenomanian age for the Plenus Marl, from which most studied coprolites derive. The findings of this study highlight the potential of a multi‐proxy approach when it comes to unravelling the origin, composition and importance of coprolites in palaeoecosystem analyses.     

First record of Mesozoic scroll coprolites: classification,characteristics, elemental composition and probable producers

Multiple, small, cylindrical scroll coprolites having rounded and tapering ends and pertaining to a new ichnotaxon have been recovered from the Upper Triassic Tiki Formation of India. This is the first record of scroll coprolites from the Mesozoic. Based on cross‐sectional geometry, external surface textures, and internal morphology, these coprolites are subdivided into three morphotypes. The coprolites contain several kinds of undigested food material in the form of ganoid fish scales, teeth, lower jaw and skeletal remains of various osteichthyans, chondrichthyans, archosauriforms and indeterminate reptiles. These inclusions are embedded in the groundmass separated by thin mucosal layers. The groundmass contains abundant gas vesicles, and secondarily‐filled shrinkage cracks. EDS analysis shows that the overall composition of the coprolites reflects Ca, P, C and O, suggesting calcium phosphate mineralogy, though other elements such as Fe, Mn, Al, Si are present in lesser proportions. Based on their similarity with the scrolled faeces of extant euryhaline hammerhead sharks, it is deduced that these coprolites were produced by euryhaline hybodontid sharks. At least two hybodontid taxa, Lonchidion and Pristrisodus, show high prevalence in the Tiki vertebrate fauna, suggesting that these were the possible producers. As the coprolite inclusions contain remains of other aquatic animals, these carnivorous hybodonts constituted the dominant predators of the Tiki aquatic ecosystem.     

Microbiota and food residues including possible evidence of pre‐mammalian hair in Upper Permian coprolites from Russia

Coprolites (fossil faeces) provide direct evidence on the diet of its producer and unique insights on ancient food webs and ecosystems. We describe the contents of seven coprolites, collected from the Late Permian Vyazniki site of the European part of Russia. Two coprolite morphotypes (A, B) contain remains of putative bacteria, cyanobacteria, fungi, protists, invertebrate eggs, arthropod elements, undigested bone and tooth fragments, fish scales and elongated hair‐like structures with hollow interiors. Content, size and shape of the coprolites together with the associated body fossil record suggest that the most probable scat‐producers were carnivorous tetrapods; the bone‐rich morphotype A reveals short food retention time and a fast metabolism and is therefore assigned to therapsid carnivores whereas morphotype B with rarer and degraded bones are assigned to archosauromorphs or other non‐therapsid carnivores. The general coprolite matrix contains abundant micron‐sized spheres and thin‐walled vesicles which are interpreted as oxide and phosphatic pseudomorphs after microbial cells. From analyses of the undigested bones, we infer that they represent remains of actinopterygian fish, a therapsid and unrecognizable parts of amphibians and/or reptiles. Additionally, hair‐like structures found in one coprolite specimen occur as diagenetically altered (oxide‐replaced) structures and moulds (or partly as pseudomorphs) in a microcrystalline carbonate‐fluoride‐bearing calcium phosphate. This suggests that the latest Permian therapsids probably were equipped with hair‐like integument or hairsuit. If true, this is by far the oldest evidence of this mammalian character in the stem group of mammals.     

Gar-Bitten Coprolite From South Carolina,USA

Coprolites can preserve a wide range of biogenic components. Of all the coprolites known from the fossil record, hitherto only two are known to preserve vertebrate tooth impressions (i.e., those of chondrichthyans). Here, a coprolite, from a thick lag deposit that includes a mixture of late Cretaceous, early Paleocene, and Plio-Pleistocene taxa at Clapp Creek in Kingstree, Williamsburg County, South Carolina, USA, preserves bite marks most consistent with having been made by a gar, Lepisosteus sp. (Lepisosteidae, Actinopterygii). This is the first-known coprolite to preserve actinopterygian tooth/bite marks. Aborted coprophagy seems unlikely; an accidental or serendipitous strike more likely describes the origin of the score marks over the surface of the coprolite. This coprolite also preserves small paired striations interpreted as evidence of coprophagy by an unknown organism.     

贵州兴义中三叠世拉丁期兴义动物群粪化石*

粪化石是重要的遗迹化石, 其内含物信息可为讨论生物行为、生理、相互关系、古环境等提供重要证据, 进而对恢复和重建地质历史时期的生态系统等有重要意义。本文首次报道了贵州省兴义市泥麦古剖面中三叠世拉丁期兴义动物群化石层第35自然层的7种不同形态的粪化石。通过观察粪化石的内含物情况, 发现其主要由贵州龙骨骼和鱼鳞组成,极少含有无脊椎动物碎片, 表明粪化石来源于非壳食性的肉食性动物。依据粪化石的尺寸、缺少螺旋结构及相对较小的内含物碎片等信息, 排除动物源是无脊椎动物、大型肉食性鱼类及大型鱼龙类的可能。结合兴义动物群下部化石组合海生爬行类实体化石的信息, 进一步推断所研究粪化石的动物源应为非鱼龙的海生爬行动物,很可能是幻龙类、鸥龙类或海龙类。本文报道的7种形态的粪化石显示该下部化石层中的海生爬行动物之间至少存在1级营养等级的差异, 这为恢复和重建中三叠世拉丁期海洋生态系统提供了重要依据。另外微生物的参与及泥质含量较高的厌氧环境使得该层的粪化石保存完好。     

Opportunistic exploitation of dinosaur dung: fossil snails in coprolites from the Upper Cretaceous Two Medicine Formation of Montana

Multiple associations of fossil snails with dinosaur coprolites demonstrate that snails and dinosaurs not only shared ancient habitats but were trophically linked via dinosaur dung. Over 130 fossil snails representing at least seven different taxa have been found on or within herbivorous dinosaur coprolites from the Upper Cretaceous Two Medicine Formation of Montana. The terrestrial snail Megomphix is the most common taxon, but three other terrestrial taxa (Prograngerella, Hendersonia and Polygyrella) and three aquatic snails (Lioplacodes, ?Viviparus and a physid) also occur in coprolites. At least 46% of the shells in the faeces are whole or nearly so, indicating that most (if not all) of the snails were not ingested by dinosaurs, but were post‐depositional visitors to the dung pats. The sizeable, moist and microbially enriched dinosaur faeces would have provided both food and roosting sites for the ancient snails, and the large number of snail–coprolite associations reflect recurring, opportunistic exploitation of dung. The terrestrial taxa in the coprolites suggest that this Late Cretaceous locality included sufficiently moist detrital or vegetative cover for snails when dinosaur dung was not present. The aquatic snails probably entered the faeces during flood events. Dinosaur dung would have provided an abundant but patchy influx of resources that was probably seasonally available in the ancient environment.     

New record of anoplocephalid eggs (Cestoda: Anoplocephalidae) collected from rodent coprolites from archaeological and paleontological sites of Patagonia,Argentina

Results of paleoparasitological examination of rodent coprolites collected from archaeological and paleontological sites from Patagonia, Argentina, are present. Each coprolite was processed, rehydrated, homogenized, spontaneously sedimented and examined using light microscope. Coprolites and eggs were described, measured and photographed, and were compared with current faeces of Lagidium viscacia. Eggs with morphological features, attributed to an anoplocephalid cestode were found in samples collected from Cueva Huenul 1 (36°56′45″S, 69°47′32″W, Neuquén Province, Holocene) and Los Altares Profile (43º53′35″S, 68º23′21″W, Chubut Province, Late Holocene). These are the first findings of this anoplocephalid from faecal material from patagonic rodents.     

Coprolites from shallow marine deposits of the Nanjemoy Formation,Lower Eocene of Virginia,USA

The Eocene Nanjemoy Formation crops out on the Maryland and Virginia Coastal Plain, along the eastern coast of the United States. This formation is composed of sands, silts and clays and is divided into the Potapaco and Woodstock members. Remains of fishes, reptiles, birds, mammals, molluscs, fruits and seeds are common in the Potapaco Member, in addition to vertebrate coprolites. Here, we present an analysis of more than 2000 coprolites from the Fisher/Sullivan Site in Virginia. The chemical composition (phosphatic) and the type of inclusions (fish bones) indicate that only scats of carnivorous animals were preserved. The analysed specimens were grouped into six morphotypes: (1) the cylindrical morphotype is a cylinder with rounded ends; (2) the segmented morphotype is a cylinder segmented with rounded ends, and occasionally one end is concave; (3) the oval morphotype represents a bean‐shaped coprolite; (4) the scroll morphotype is cylindrical to conical in lateral view and has coils seen only at the ends; (5) the folded morphotype is a spiral that is concentrically folded; and (6) the sinuous morphotype is serpentine, with rounded ends. Coprophagy‐related scrape traces occur in different morphotypes and represent both invertebrate burrows and bite traces made by fishes. The mineralogical and chemical analyses indicate an early precipitation of phosphate and pyrite minerals, probably induced by the microbial community. All coprolites at the Fisher/Sullivan Site were produced by fishes: carcharhiniform sharks for the scroll morphotype and lamniform sharks, probably the genus Carcharias, for the folded morphotype; the oval, cylindrical and segmented morphotypes were likely produced by actinopterygian fishes.     

Turtle Shell Impression in a Coprolite from South Carolina,USA

Coprolites (fossilized feces) can preserve a wide range of biogenic components. A mold of a hatchling turtle partial shell (carapace) referable to Taphrosphys sulcatus is here identified within a coprolite from Clapp Creek in Kingstree, Williamsburg County, South Carolina, USA. The specimen is the first-known coprolite to preserve a vertebrate body impression. The small size of the turtle shell coupled with the fact that it shows signs of breakage indicates that the turtle was ingested and that the impression was made while the feces were still within the body of the predator. The detailed impression could only have survived the act of defecation if the section of bony carapace was voided concurrently and remained bonded with the feces until the latter lithified. Exceptionally, the surface texture of the scutes is preserved, including its finely pitted embryonic texture and a narrow perimeter of hatchling scute texture. The very small size of the shell represented by the impression makes it a suitable size for swallowing by any one of several large predators known from this locality. The coprolite was collected from a lag deposit containing a temporally mixed vertebrate assemblage (Cretaceous, Paleocene and Plio-Pleistocene). The genus Taphrosphys is known from both sides of the Cretaceous–Paleogene (K–Pg) boundary so, based on the size of the coprolite and the locally-known predators, the juvenile turtle could have been ingested by a mosasaur, a crocodylian, or a theropod dinosaur. Unlike mosasaurs and theropod dinosaurs, crocodylian stomachs have extremely high acid content that almost always dissolves bone. Therefore, the likely predator of this turtle was a mosasaur or a (non-avian or avian) theropod dinosaur.     

Early Triassic coprolites from Australia and their palaeobiological significance

Abstract:  Coprolites from the Arcadia Formation, Queensland, Australia, were studied in conjunction with the vertebrate fossil assemblages from two localities to maximize our understanding of the palaeoecology of these Early Triassic deposits. Criteria used by other researchers to identify the producers of coprolites were found to be of little value in the Arcadia Formation specimens. Using a combination of shape, biostratigraphic distribution, size and included remains some of the coprolites are attributed to basal archosauromorphs and fish whereas others could not be identified. Perhaps the most important attribute of the Arcadia coprolites is that they preserved rare organisms such as cyanobacteria, insects and other arthropods, and a diversity of fish. Estimates of the number of actinopterygians and dipnoans preserved in coprolites significantly increased relative abundance estimates based on skeletal elements alone. Although coprolites are an important source of palaeobiological information, this information is limited by our poor understanding of the taphonomic processes involved in the fossilization of faecal matter and by the near impossibility of assigning coprolites to specific producers.     

Paleocene Thalassinidea colonization in deep-sea environment and the coprolite Palaxius osaensis n. ichnosp. in Southern Costa Rica

Palaxius osaensis n. ichnosp., a new ichnospecies of crustacean coprolite is described. The coprolite is preserved in a 200-m thick Paleocene sequence in Southern Costa Rica that is largely dominated by pillow basalts. The studied sample is part of a seamount formed in the Pacific Ocean that was accreted to the Central American isthmus during the Eocene. The absence of lava vesicles, shallow-water deposits, and detrital sediments in the section suggest that the coprolites were deposited in a deep environment during the first stage of the development of the seamount. This represents one of the deepest occurrences of Thalassinidea coprolites reported in the literature and indicates that the producers of the coprolites, presumably some shrimps, developed the aptitude to colonize abyssal environments at least since Early Tertiary. The crustacean coprolites were encountered at a site which apparently lacked a food supply, although hydrothermal processes are believed to have provided the opportunity for a chemotrophic community to develop on the deepest part of the seamount. P. osaensis n. ichnosp. is also found in Colombia in late Cretaceous shallow-water sediments that notably contain Palaxius caucaensis coprolites (Micropaleontology 41 (1995) 85-88). Occurrences of P. osaensis n. ichnosp. deposited at both shallow and deep levels may possibly be related to an aptitude of some thalassinid organisms to have developed in various biotopes during the late Cretaceous-Paleocene.     

A new actinomycete from a Guadalupian vertebrate coprolite from Brazil

Coprolites (fossil feces) are important sources of evidence of ancient food webs and ecosystems. Actinomycetes are a fundamental component in the decay of organic matter, and serve as catalysts for nutrient cycles. Recently, gas vesicles filled with numerous verrucose colonies of substrate mycelium of an actinomycete were discovered inside a fossilized spiral amphipolar fish coprolite recovered from mid–Permian deposits of Brazil. These colonies are composed of masses of substrate hyphae, some of which are undergoing segmentation. Arising from the colonies are chains of spores separated by narrow, elongate connectives. The fossil actinomycete is described below as Palaeostromatus diairetus gen. et sp. nov. and represents the oldest known actinomycete associated with vertebrate deposits. Since the colonies occur only inside the coprolite, either Palaeostromatus diairetus gen. et sp. nov. was part of the gut flora or it was acquired from a food source. The only other remains in the coprolite are eighteen paleoniscoid fish scales, which suggests that the producer was a carnivorous/omnivorous fish. This is the oldest record of a direct interaction between vertebrates and actinomycetes.     

Coprolites from the Maastrichtian Whitemud Formation of southern Saskatchewan: Morphological classification and interpretation on diagenesis

Alluvial floodplain mudstones of the late Maastrichtian Whitemud Formation of southern Saskatchewan contain abundant vertebrate faecal remains preserved as siderite and Fe-hydroxides. The coprolites are grouped into nine morphological classes on the basis of style of coiling, shape, size, and striations. Their morphology is consistent with deposition of the faeces by terrestrial reptiles and not by fish as previously reported. The excellent preservation of the fossils can be attributed to early diagenetic precipitation of Fe CO₃ in loci where faecal matter was still bacterially fermenting.     

Paleomicrobiology: Revealing Fecal Microbiomes of Ancient Indigenous Cultures

Coprolites are fossilized feces that can be used to provide information on the composition of the intestinal microbiota and, as we show, possibly on diet. We analyzed human coprolites from the Huecoid and Saladoid cultures from a settlement on Vieques Island, Puerto Rico. While more is known about the Saladoid culture, it is believed that both societies co-existed on this island approximately from 5 to 1170 AD. By extracting DNA from the coprolites, followed by metagenomic characterization, we show that both cultures can be distinguished from each other on the basis of their bacterial and fungal gut microbiomes. In addition, we show that parasite loads were heavy and also culturally distinct. Huecoid coprolites were characterized by maize and Basidiomycetes sequences, suggesting that these were important components of their diet. Saladoid coprolite samples harbored sequences associated with fish parasites, suggesting that raw fish was a substantial component of their diet. The present study shows that ancient DNA is not entirely degraded in humid, tropical environments, and that dietary and/or host genetic differences in ancient populations may be reflected in the composition of their gut microbiome. This further supports the hypothesis that the two ancient cultures studied were distinct, and that they retained distinct technological/cultural differences during an extended period of close proximity and peaceful co-existence. The two populations seemed to form the later-day Taínos, the Amerindians present at the point of Columbian contact. Importantly, our data suggest that paleomicrobiomics can be a powerful tool to assess cultural differences between ancient populations.     

Hyena hegemony: biogeography and taphonomy of Pleistocene vertebrate coprolites with description of a new mammoth coprolite ichnotaxon

Abstract

In 1822, William Buckland first recognized Pleistocene vertebrate coprolites, and they are now known from more multiple localities with a global distribution. Carnivore coprolites dominate, and there are two distinct biogeographic and taphonomic provinces for vertebrate coprolites in the Pleistocene. The Castrocopros province of North and South America is characterized by a dominance of herbivore coprolites, which are preserved almost exclusively in caves. The Hyaenacoprus province in Africa, Europe and Asia is dominated by hyena coprolites that occur mainly in caves, but also in other depositional environments. Pacific Islands may represent a third province characterized by dominant bird coprolites from caves, but the known localities are all Holocene. Mammuthocopros allenorum ichnogen. and ichnosp. nov. is a coprolite of Mammuthus columbi from Utah, USA.     

A palaeoparasitological analysis of rodent coprolites from the Cueva Huenul 1 archaeological site in Patagonia (Argentina)

The aim of the present study was to examine the parasite fauna present in rodent coprolites collected from Cueva Huenul 1 (CH1), northern Neuquén (Patagonia, Argentina), an archaeological site that provides stratified sequences of archaeological and palaeontological remains dating from the Late Pleistocene/Early Holocene Transition to the Late Holocene period. Twenty rodent coprolites collected from different sedimentary units from the site, with ages ranging from 13.844 ± 75-1.416 ± 37 years BP, were examined for parasites. Each coprolite was processed as a whole: rehydrated, homogenised, spontaneously sedimented and examined using light microscopy. The coprolites and the eggs of any parasites present were described, measured and photographed. In all, 158 parasite eggs were found in 10 coprolites. The faeces were positive for Viscachataenia quadrata Denegri, Dopchiz, Elissondo & Beveridge and Monoecocestus sp. Beddard (Cestoda: Anoplocephalidae) and for Heteroxynema (Cavioxyura) viscaciae Sutton & Hugot (Nematoda: Oxyuridae). The coprolites examined were tentatively attributed to Lagidium viscacia Molina (Mammalia, Rodentia, Caviomorpha, Chinchillidae). The life cycles of these parasites are discussed.     

Enigmatic origin of massive Late Cretaceous‐to‐Neogene coprolite‐like deposits in North America: a novel palaeobiological alternative to inorganic morphogenesis

Innumerable coprolite specimens, alternatively pseudo‐coprolites, are distributed in several Late Cretaceous‐to‐Neogene continental deposits hosted by the Whitemud Formation (Maastrichtian) in southern Saskatchewan, Canada, Golden Valley Formation (Paleocene) in western North Dakota and the Wilkes Formation (Miocene) in Washington State, USA. These massive accumulations of excrement‐shaped specimens also include multi‐decimetre‐long specimens previously interpreted as casts of intestinal organs by an unknown zoology, possibly reptilian. The possible vertebrate zoology origin of these has been widely disputed because of the lack of any skeletal remains or any other definitive evidence of palaeobiology. Alternative originations suggest non‐zoological processes, such as sideritic muds extruded by biogenic gas‐driven flows during diagenesis. Multi‐decimetre‐long intestine‐like casts recovered from the three deposits differ from the more widely distributed faeces‐like specimens because their elongated forms have bilateral symmetry in cross‐section and surface textures consisting of sub‐mm‐wide longitudinal parallel striations extending without interruption along the looped and coiled surfaces. These possible impressions of musculature are not present on smaller specimens having coprolite‐like shapes. A novel interpretation proposes that these multi‐decimetre‐long specimens may be gut casts of a previously unrecognized giant terrestrial earthworm (Oligochaeta) that existed from the Late Cretaceous to the Neogene. The possibility of this Annelida zoology provides palaeobiological resolution for the lack of any evidence of vertebrate skeletal remains or other evidence of origination and further suggests that the innumerable excrement‐like specimens may also have palaeobiological affinity.     

First paleoparasitological study of micromammal coprolites from the holocene of the Somuncurá Plateau Protected Natural Area (Patagonia Argentina)

The Somuncurá Plateau is a Protected Natural Area located in the middle of the northern extra-Andean arid Patagonia. Inhabited by at least 20 small mammal species, is the place with the uppermost species richness in Patagonia. The aim of this study was to examine the parasite remains from micromammal coprolites collected in association with a bone sequence recovered at the east of the Somuncurá Plateau (site “Alero Las Lechuzas”). Coprolites came from the four temporal units previously defined: unit I (4790?±?100?yrs. ¹⁴C B.P.), unit II, unit III (7840?±?120?yrs. ¹⁴C B.P.) and unit IV. Each coprolite was processed, rehydrated, homogenized, processed by spontaneous sedimentation and examined using a light microscope. Coprolites and eggs were described, measured and photographed. Samples were positive for two nematode species: Helminthoxys caudatus Freitas, Lent & Almeida, 1937 (Oxyurida, Oxyuridae) and Trichuris spp. (Trichinellida: Trichuridae). This is the first paleoparasitological study developed for the Somuncurá Plateau Protected Area. Moreover, this is the first time that the genus Helminthoxys is reported from ancient times worldwide. Coprolites were attributed to the mountain cavy Microcavia australis (Rodentia, Caviidae).The presence of H. caudatus for the Middle Holocene of northern Patagonia contributes to the study of the history of the histricomorphs and pinworms relationships.     

A fresh look at ancient dungs: the Brazilian Triassic coprolites revisited

Terrestrial tetrapod coprolites are abundant in the Middle to Late Triassic of southern Brazil, but only few specimens have been described in just a couple of papers. Here we revisit the already‐known specimens and describe new materials, including their size, shape, external modifications, matrix composition and rare inclusions. Regarding size and shape, the measurements of 152 specimens show that the Triassic coprolites of Brazil follow a normal distribution, in which length and width are positively correlated variables, so that they are not useful for taxonomic purposes. Notwithstanding, two ichnotaxa, Santamariacopros elongatus and Rhynchocopros soutoi, were previously described from the Middle/Upper Triassic Santa Maria Formation, based mainly on morphological (length/width ratio) and preservational features, but we discuss here the validity of such taxa. Once the Santa Maria Formation encompasses at least three tetrapod Assemblage Zones (AZ), Dinodontosaurus AZ, Santacruzodon AZ and Hyperodapedon AZ (from the oldest to the youngest, respectively), it is difficult to attribute these coprolites to any specific animal producers. In addition, the rarity of inclusions and the carbonated composition of the coprolites, related to early diagenetic processes, complicate this attribution too. Nevertheless, some rare inclusions as a hair‐like structure and a parasite egg were found in this study. Although the coprotaxonomy fails to represent the Santa Maria Formation coprolites and the recognition of their producers is a problematic task, these fossil dungs are important elements in the knowledge of the Middle to Late Triassic environments of southern Brazil.     

Turiasauria-like teeth from the Upper Jurassic of the Lusitanian Basin,Portugal

Turiasauria is a clade of eusauropods with a wide stratigraphic range that could extend from the Bathonian to the lower Aptian including Turiasaurus, Losillasaurus, Zby and putatively, Galveosaurus, Atlasaurus and isolated remains from Middle Jurassic-to-Lower Cretaceous. Some are characterised by the presence of heart-shaped teeth. Several tooth occurrences from the Portuguese Upper Jurassic with this type of morphology (SI: 1.1–1.8) are reported and discussed. If this morphology is regarded as synapomorphic of Turiasauria, the teeth will be tentatively related to this clade. From a sample of 43 teeth, three main morphotypes are described. Three hypotheses might explain the morphological variation: (1) the range of tooth morphologies indicates variation in the jaw, (2) the range of tooth morphologies indicates taxonomic variation or (3) a combination of both. The general wear pattern in morphotypes I and II starts with a distal facet, then the appearance of mesial/apical facet and finally a ‘V’-shaped facet. In morphotype III, the wear begins with a mesial facet. The variability observed for Portuguese Upper Jurassic specimens is congruent with the morphological variability along the tooth row shown by other sauropods with spatulate/spoon-shaped teeth and it is considered the most parsimonious hypothesis to explain it.