Calvert Marine Museum

A description and analysis is given of a single physeteroid tooth, from the Neogene of the Nutrien Aurora Phosphate Mine (formerly known as the Lee Creek Mine, Aurora, North Carolina, USA), that was bitten either by the extinct megatoothed shark Otodus chubutensis or Otodus megalodon. The tooth shows three gouges, one of which also preserves raking bite traces, made as the serrations on the Otodus sp. tooth struck and cut into its surface. We do not know if these bite traces came about as a result of scavenging or active predation. However, because the bite traces occur on part of the skull, this suggests a predatory interaction. This tooth preserves the first evidence in the fossil record of a predatory/antagonistic interaction between a sperm whale and a megatoothed shark.

Color specification is the process of measuring the color of a sample in a given color space. We focused onto the Munsell color space as archaeologists are used to employ the so called Munsell Soil Color Charts (MSCCs) directly in the excavation sites. For these scholars and researchers, being enabled to perform Munsell color specification in an automatic way is crucial, as they spend a lot of time to subjectively specify colors in the Munsell system. We extended the dataset ARCA328, which was specifically thought for the automatic Munsell color specification issue, increasing the number of images from 328 to 1,488, and the number of samples from 56,160 to 315,333. Then, we conducted generalization-tests of color conversion for color specification, adopting a classification approach instead of a regression one. This choice was motivated by the fact that the set of all the possible HVC coordinates in the MSCCs is a discrete one. Hence, we decided to consider each chip in the MSCCs as a class to be learnt and recognized by the SVC. With these tests we highligthed the limits of automatic Munsell color specification without any reference-system or calibration phase. Finally, we gave insights for future works aimed to design automatic illuminant calibration phase and to investigate deep learning approaches, leveraging a synthetic images rendering procedure we also present in this work.

ABSTRACTCoprolites (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.

The vertebrate fauna from the Lower Cretaceous Patuxent Formation of Virginia is composed of a single partial fish impression from the James River at Dutch Gap and a diverse tetrapod ichnofauna from near Fredericksburg that includes trace fossils made by frogs, turtles, theropods, sauropods, ankylosaurs, and ornithopods. The footprints occur on overbank deposits preserved locally within a fluvial braided-stream sequence that formed near the western border of the Early Cretaceous Atlantic Coastal Plain.

ABSTRACT Shark teeth are the most common vertebrate fossils found along the western shore of Chesapeake Bay at Calvert Cliffs in Maryland. The stratigraphic distribution of teeth within the cliffs has not yet been documented. We utilized museum collections of in situ teeth to access their distribution within stratigraphic beds and a large selection of float teeth retrieved from Calvert County beaches as a proxy for the distribution of teeth within stratigraphic beds and across underlying beaches. Museum collections provide 1,866 teeth recorded in situ; float collections yield a total of 24,409 teeth. These data sets offer different, but complementary, results. Miocene sediments along Calvert Cliffs comprise the Calvert, Choptank, and St. Marys formations. Over 96% of all teeth in the in situ data set derive from the Calvert Formation, likely due to favorable paleoenvironmental conditions for sharks. The non-uniform stratigraphic distribution of teeth is further supported by an uneven distribution of teeth collected on beaches below the cliffs. Samples from northern localities contained more float specimens; cliffs in this area are composed almost entirely of the Calvert Formation. Fifteen genera are represented in the in situ and float collections. The main constituents are Carcharhinus spp., Hemipristis serra, Galeocerdo spp., Isurus spp., and Carcharias spp. Most of these genera exhibit significant unidirectional trends in the proportional abundance of teeth across Calvert Cliffs beaches. Factors influencing these variations remain unclear, but the overall dominance of carcharhiniforms over lamniform and other sharks observed for the Miocene persists in modern nearshore environments.

Eight Miocene odontocete partial rostra (six specimens from the Chesapeake Group of Maryland, one from the Chesapeake Group of Virginia, and another from the Hawthorn Group of Florida) exhibit periostitis, of unknown etiology, characterized by proliferative bone growth. Periostitis is an inflammation of the periosteum secondary to a predisposing event such as a fracture or infection. Computed tomography reveals that the lesions are limited to the premaxillae and that they became progressively swollen and gnarled as evidenced by the onion-like layering within the deformity. The level of maturity and degree of organization of the periostitis indicates that it likely developed over a period of months or years in these individuals. Given this length of time, these pathologies seem not to have been life-threatening despite the gross size and shape of most of these periosteal reactions. The fossils range in age from about 11 to 15 million yr and all eight rostra appear to be derived from the same, but as yet unnamed or unrecognized species of odontocete. The family from which these odontocetes derive remains unknown. Un-deformed rostra attributed to this species have not been identified, which opens the possibility that “abnormal” was the new normal for this species of odontocete.

ABSTRACT Stenasodelphis russellae, a new genus and species of extinct dolphin in the odontocete family Pontoporiidae, is based on a partial cranium of Late Miocene age (Tortonian), circa 9 to 10 Ma, from the Little Cove Point Member of the St. Marys Formation, Maryland, USA. Pontoporiidae are amongst the smallest cetaceans, and this dolphin is one of the smallest reported pontoporiids, being probably less than 1.5 m long. It is also the second oldest named pontoporiid in the world. Stenasodelphis russellae shares with late Middle Miocene Brachydelphis mazeasi (eastern South Pacific) and the latest Miocene and Pliocene species of Parapontoporia (North Pacific) left-skew asymmetry of the cranial vertex. Thus, all of the earliest known Pontoporiidae have cranial asymmetry, in contrast to symmetrical crania in the Pliocene pontoporiids, Pontistes rectifrons and Pliopontos littoralis, and the Recent Franciscana, Pontoporia blainvillei. This suggests that cranial asymmetry may be the primitive character state among stem Pontoporiidae. Autapomorphies of Stenasodelphis russellae include small size, thick cranial bones, wide premaxillary sac fossae, a medial projection of each maxilla onto the lateral side of each nasal, and the highest part of the cranial vertex being formed by the nasals rather than the frontals.

The vast majority of the more than 600 species that have been identified from the Miocene sediments of Calvert Cliffs, Maryland (Fig. 1), are of marine organisms. The biota includes palynomorphs, terrestrial plants, diatoms, dinoflagellates, foraminiferans, sponges, annelid worms, corals, abundant and diverse mollusks, ostracods, decapod crustaceans, barnacles, an inarticulate brachiopod, echinoderms, sharks and rays, bony fishes, turtles, crocodiles, pelagic birds, seals, sea cows, isolated and fragmentary remains of large terrestrial mammals, and a diverse assemblage of approximately 30 species of both odontocetes and mysticetes (Gottfried et al., 1994). In terms of vertebrate remains, those of cetaceans are second only to the number of chondrichthian teeth that erode from the length of Calvert Cliffs and their extensions out under the waters of the Chesapeake Bay. The three Miocene formations comprising Calvert Cliffs (Fig. 2) differ in their cetacean assemblages. The Lower Miocene to lower Middle Miocene (Burdigalian and Langhian) Calvert Formation has long been known to preserve one of the world's richest and most diverse extinct cetacean assemblages. Of the 19 recognized odontocete species from the Chesapeake Group, 12 are known exclusively from the Calvert Formation and another three are derived from both the Calvert and the Middle Miocene (Serravallian) Choptank formations (to date, no odontocete spe