1,721,165 research outputs found
The occurrence of the coronuloid barnacle Chelonibia Leach, 1817 as an encruster on mammalian bone in the central Mediterranean Sea
Full text linkMeđu kornjačama i kitovima (Coronuloidea: Chelonibiidae, Coronulidae, † Emersoniidae i Platylepadidae), pripadnici vrste Chelonibia testudinaria (Linnaeus, 1758) poznati su kao epizoični brumbuljci koji se mogu pričvrstiti na prilično širok spektar podloga (prvenstveno na kornjače, rakove i velike vodene sisavce koji se hrane biljkama iz reda Sirenia). Trenutno su prepoznate tri živa morfija C. testudinaria; od njih, manje specifična za domaćina je morph patula, koja također prikazuje izuzetno jednostavnu, nespecijaliziranu arhitekturu ljuske. U ovom radu izvještavamo o nekoliko ljuski helonibiida, koje se odnose na morfe patule C. testudinaria, koja inkrustira lopaticu kitova sakupljenu s dna Jadranskog mora prema Salentu (regija Apulia, jugoistočna Italija) i okvirno upućenu na Tursiops truncatus (Montagu, 1821). Ovo je jedan od rijetkih zapisa u svijetu o brumbuljku iz nežive podloge, a i kao drugi slučaj inkrustriranja na kosti sisavca. Takva neobična pojava potom se ukratko raspravlja u širem kontekstu komensalizma brumbuljaka i supstrata staništa.Among the turtle and whale barnacles (Coronuloidea: Chelonibiidae, Coronulidae, †Emersoniidae and Platylepadidae), the members of the chelonibiid species Chelonibia testudinaria (Linnaeus, 1758) are known as epizoic barnacles that can attach to a rather wide spectrum of substrates (primarily sea turtles, crabs and sirenians). At present, three living morphs of C. testudinaria have been recognised; of these, the less host-specific is the patula morph, which also displays a remarkably simple, unspecialised shell architecture. Here we report on several chelonibiid shells, referred to the patula morph of C. testudinaria, encrusting a cetacean scapula collected from the floor of the Adriatic Sea facing Salento (Apulia Region, southeastern Italy) and tentatively referred to Tursiops truncatus (Montagu, 1821). This is one of the few records worldwide of a coronuloid barnacle from an inanimate substrate, as well as the second as an encruster on mammalian bone. Such an unusual occurrence is then briefly discussed in the broader framework of the coronuloid commensalism and substrate habits
An overview of the fossil record of cetaceans from the East Pisco Basin (Peru)
No full textThe East Pisco Basin is one of the forearc basins that formed during the Cenozoic along the coast of Peru due to the subduction of the Farrallon-Nazca plate beneath the South American plate. The sedimentary fill of this basin is extensively exposed along the coastal Ica Desert, and includes a succession of Eocene to Pliocene marine sediments that account for a ~50-myr-long history of semicontinuous deposition. These rocks are characterized by an outstanding fossil content that remarkably contributed to our understanding of the evolutionary history of the main groups of Cenozoic marine vertebrates. In the Ica desert, the most common and significant vertebrate remains belong to cetaceans. Knowledge on the fossil cetaceans of the East Pisco Basin has grown dramatically in the last fifteen years thanks to several international research projects involving, among many others, the authors of the present article. These research efforts have led to the discovery of several hundred fossil skeletons, the most significant of which have been collected, prepared and partly published. Furthermore, interdisciplinary studies were also conducted in order to provide a high resolution chronostratigraphic framework for this fossil record. Remarkable cetacean specimens come from the Yumaque member of the Paracas Formation (middle to late Eocene), the Otuma Formation (late Eocene), the Lower Miocene (~19-18 Ma) portion of the Chilcatay Formation, and allomembers P0 (14.8-12.4 Ma), P1 (9.5-8.5 Ma) and P2 (8.4-6.7 Ma) of the Middle Miocene to Pliocene Pisco Formation. The Lutetian (42.6 Ma) Yumaque strata are home to the quadrupedal protocetid archaeocete Peregocetus pacificus, which documents the first arrival of cetaceans in the Pacific Ocean. Geologically younger (36.4 Ma) Yumaque deposits have yielded the holotype skeleton of Mystacodon selenesis, the oldest mysticete ever found. This ancestor of the modern baleen whales had a skull provided with a complete dentition and retained hindlimbs, albeit reduced in size. In the Otuma Formation, a nine-m-long basilosaurid (Cynthiacetus peruvianus) has been discovered. The Chilcatay Formation records the first great radiation of the odontocetes, represented by Inticetidae (Inticetus vertizi), basal Platanidelphidi (Ensidelphis riveroi), Squalodelphinidae (Furcacetus flexirostrum, Huaridelphis raimondii, Macrosqualodelphis ukupachai and Notocetus vanbenedeni), Platanistidae (aff. Araeodelphis), Physeteroidea (Rhaphicetus valenciae and cf. Diaphorocetus), Chilcacetus cavirhinus, indeterminate Eurinodelphinidae, and Kentriodontidae (Kentriodon). Overall, this roughly coeval assemblage displays a considerable disparity in terms of skull shape and body size that is possibly related to the development of different trophic strategies, ranging e.g., from suction to raptorial feeding. In the Pisco Formation, starting from P0, the baleen-bearing whales (Chaeomysticeti) represent the most frequent cetacean fossils (only a few mysticetes are known from the Chilcatay strata). Two chaeomysticete lineages are found in the Pisco Formation: Cetotheriidae (from Tiucetus rosae in P0 to Piscobalaena nana in P2) and Balaenopteroidea (from Pelocetus in P0 to several undescribed species of Balaenopteridae in P2, testifying to a progressive trend toward gigantism). Odontocetes are rare in P0, the “kentriodontid” Incacetus broggii being the only species described from these strata, but they become more abundant and diverse in P1 and P2. In P1, the commonest toothed whale is Messapicetus gregarius, a member of Ziphiidae featuring an extremely elongated rostrum and a complete set of functional teeth. Another ziphiid from P1 is Chimuziphius coloradensis, known only from the fragmentary holotype cranium. The P1 strata also record the appearance of the crown Delphinida, with the superfamily Inioidea being represented by two small pontoporiids (Brachydelphis mazeasi and Samaydelphis chacaltanae) and one iniid (Brujadelphis ankylorostris). Moreover, P1 is also home to the stem physeteroid Livyitan melvillei; featuring a three-m-long skull and teeth reaching 36 cm in length, L. melvillei was one of the largest raptorial predators and, possibly, the biggest tetrapod bite ever found. Acrophyseter is another macroraptorial sperm whale, distinctly smaller than L. melvillei, known from both P1 and P2. Even smaller in size are the kogiids Platyscaphokogia landinii and Scaphokogia cochlearis, both of which are known from the upper strata of P2. The same allomember is also home to the ziphiids Chavinziphius maxillocristatus and Nazcacetus urbinai, the “kentriodontids” Atocetus iquensis and Belenodelphis peruanus, and undescribed members of Phocoenidae
How to break a sperm whale’s teeth: dental damage in a large Miocene physeteroid from the North Sea Basin
No full textIn contrast to the suction-feeding, predominantly teuthophagous extant sperm whale, several Miocene physeteroids display proportionally larger teeth, deeply embedded in both upper and lower jaws. Together with other osteological features, these differences lead to the functional interpretation of these taxa as macroraptorial predators, using their teeth to capture and process large marine vertebrates. However, the assumption that strong forces applied to macroraptorial physeteroid teeth during powerful bites and contacts with bone material should result in major dental damage has not yet been tested. In the present work, we analyzed a large collection of physeteroid teeth with an enameled crown from the Miocene of the North Sea Basin. We especially focused on a set of 45 teeth of Scaldicetus caretti discovered in Antwerp (Belgium, southern North Sea Basin) and tentatively dated to the Tortonian (early late Miocene). Visual inspection and computed tomography (CT) scans revealed dental damage, including wear and breaks. The latter could be interpreted as chipping fractures, occurring along the crown, and vertical root fractures, observed along the apical part of the massive root. Chipping fractures are most likely due to contacts with hard material, whereas vertical root fractures may result from the application of strong and repetitive bite forces and/or contacts with hard material. Such results further support the interpretation of a series of Miocene physeteroids with proportionally large teeth as macroraptorial (rather than suction-feeding) top predators. Considering the size of the teeth of S. caretti, its most likely prey items were other large marine vertebrates
The holocene Ursus arctos from "Abisso Oriano Coltelli" cave (Apuan Alps, Tuscany, Central Italy)
Full text linkThe study of a prime adult female skeleton of brown bear, Ursus arctos, found in "Abisso Oriano Coltelli" cave is here reported. A new bone formation on the thoracic vertebrae was investigated by x-ray examination suggesting a longitudinal ligament injury caused by a circumscribed trauma, with ossified hematoma. The specimen was dated providing a conventional age of 6480 ± 40 14C ka BP (Holocene). The bear died from non-violent causes, probably during hibernation. The "Abisso Oriano Coltelli" mammal assemblage also includes Capra hircus, Martes foina and indeterminate small mammals. Standard archaeozoological parameters (NISP, MNI) have been used to calculate the relative frequency of each taxon identified in the faunal assemblage
Tracing the origins of the modern Mediterranean baleen whale fauna: hints from the fossil record
No full textThe current cetacean fauna of the Mediterranean Sea substantially represents a sub-set of the North Atlantic one. In particular, a single mysticete species (the fin whale Balaenoptera physalus) is commonly observed in the Mediterranean Sea, where it forms a well-distinct residential sub-population, whereas a few other forms of baleen whales are known from the same basin only for a small number of occasional and often dubious sightings. On the contrary, the Italian record of fossil mysticetes from the Pliocene epoch (ca. 5.3–2.6 millions of years ago) depicts a strongly different scenario, characterized by a great number of species, belonging to at least three families (Balaenidae, Balaenopteridae, and Eschrichtiidae), exploring a wide spectrum of body sizes and ecotrophic habits. The transition from the highly diversified Pliocene Mediterranean mysticete assemblage to the strongly simplified modern fauna has been substantially unexplored for a long time, mainly because of the scarcity of fossil-bearing marine deposits of Quaternary age (from ca. 2.6 millions of years ago onward), a time span which features the final establishment of permanent glacial conditions at the high latitudes of the Northern Hemisphere and consequent low mean values of sea level. Now however, investigations focusing on the few Quaternary fossil specimens of baleen whales and on the more abundant fossil record of whale barnacles (Coronula and allied forms) are highlighting a surprisingly complex Quaternary history for the Mediterranean mysticetes, featuring time intervals characterized by the occurrence of balaenid and balaenopterid communal breeding grounds, as well as periods in which the pygmy right whale Caperea occurred in the waters off South Italy. Here we present a synthesis of the ongoing research on the Quaternary history of Mediterranean baleen whales and try to trace the origin of the current monotypic Mediterranean mysticete fauna in the light of major climatic, biooceanographic, and evolutionary trends
Passato e futuro della collezione osteologica di balene e delfini del Museo di Storia Naturale dell’Università di Pisa
No full textVengono descritte le principali tappe che hanno portato all'acquisizione della collezione osteologica di balene e delfini del Museo di Storia Naturale dell’Università di Pisa, una delle più importanti a livello europeo
A new delphinid record (Odontoceti, Cetacea) from the Early Pliocene of Tuscany (Central Italy): systematics and biostratigraphic considerations
No full textA new partial delphinid skeleton (Cetacea, Odontoceti), from Pliocene sediments of Tuscany (Italy) consists of a fragmentary skull, ear bones, mandible, some vertebrae and rib fragments. The specimen is related to the Pliocene “Stenella” giulii, a species known from four specimens collected in the Pisa hills in the second half of 19th Century. “Stenella” giulii is here referred to the new genus Etruridelphis. Differences between Etruridelphis and all the extant Stenella spp. include: i) larger size of skull ii) wider and flatter premaxillae on the rostrum iii) narrower superior process of the periotic and iv) lower processus muscularis of the malleus. The dolphin is from a 25 m thick section for which foraminifera indicate an Early Pliocene outer shelf or upper slope environment (slightly before 3.98 Ma). The dolphin horizon, 13 meters above the base of the section produces Globorotalia margaritae and G. puncticulata, indicating the MPl 3 zone (Zanclean). Previous biostratigraphic analyses on other Etruridelphis specimens confirm that E. giulii is Early and Middle Pliocene in age
The origin of biogeographic segregation in the copper shark (Carcharhinus brachyurus): an integrative reconstruction based on neontological and paleontological data
No full textNowadays, the copper shark Carcharhinus brachyurus Günther, 1870 displays an antitropical, disjunct distribution in marginal-marine environments of both the hemispheres. Differing from other species of Carcharhinus, C. brachyurus inhabits temperate rather than tropical coastal waters, and its dispersal abilities are strongly conditioned by the presence of habitats suitable as nursery grounds. Here we analyze, through well-defined geological timeslices, the global fossil record of C. brachyurus in order to identify the main biogeographic dynamics that led to the present-day biogeographic segregation pattern of this requiem shark species. By integrating a thorough review of the paleontological literature with the results of recent phylogeographic analyses on extant copper shark populations, our study provides a first integrated reconstruction of the historical distributional patterns of this shark species that allows for proposing the identification of some dispersal trajectories as well as of a number of key events in the paleobiogeographic history of C. brachyurus. Our research supports the notion that the present-day distributional pattern of C. brachyurus is the product of historical biogeographic processes and events that might be traced back to an early Miocene East Pacific-central West Atlantic center of origin and likely reflect major changes in the global ocean system (including the closure of major seaways and the emergence of new oceanic circulation patterns)
[Changes of various blood parameters after an intravenous load of fructose in subjects with liver cirrhosis].
No full textA new record of Physeteroidea from the upper Miocene of the Pietra leccese (southern Italy): Systematics, paleoecology and taphonomy of a fossil macroraptorial sperm whale
Full text linkWe report on a partial skeleton of sperm whale (Cetacea, Odontoceti, Physeteroidea) from the Pietra leccese, a Miocene limestone widely exposed in the Salento Peninsula (southern Italy). This specimen was found in Tortonian strata cropping out at the Cisterna quarry, not far from the holotype of the stem physeteroid Zygophyster varolai. The presence of a deep and rectilinear groove medial to the tympanosquamosal recess of the squamosal, the bowed mandibles, and some dental features suggest that this specimen belongs to a still undescribed new genus and species of macroraptorial sperm whale that displays some affinities with the late Miocene Acrophyseter from Peru. Nevertheless, due to the incompleteness and poor preservation state of the skull, we abstain from creating a new taxon. The teeth exhibit both apical wear and deep occlusal facets, and three teeth even lost their crowns. These dental modifications suggest that the studied specimen used a raptorial feeding strategy for preying upon food items such as large-sized bony fishes or diminutive marine mammals. The bones are mostly disarticulated and broken, and some of them preserve traces hinting at the action of macro-scavengers, possibly including both sharks and bony fishes. Furthermore, the skull is pervasively encrusted by oysters, which suggests that it laid on the seafloor for a long time before being buried. This find provides new clues about the composition of the Miocene vertebrate assemblage of the Pietra leccese and indicates that various macroraptorial sperm whale species inhabited the Mediterranean Basin during the Tortonian
- …
