24 research outputs found
JUMPING FROM TURTLES TO WHALES: A PLIOCENE FOSSIL RECORD DEPICTS AN ANCIENT DISPERSAL OF CHELONIBIA ON MYSTICETES
The barnacles included in the superfamily Coronuloidea are epizoic symbionts of various marine vertebrates (including cetaceans, sirenians, and sea turtles) and other crustaceans (crabs and horseshoe crabs). Among Coronuloidea, the so-called turtle barnacles (Chelonibiidae) are known from Paleogene times, whereas the whale barnacles (Coronulidae) likely appeared in the late Pliocene (Piacenzian). Although a derivation from the turtle barnacles (and especially from the genus Chelonibia) has been proposed, the evolutionary origin of Coronulidae remains to date obscure. In this work we reappraise a fossil record from upper Pliocene (Piacenzian) marine deposits at Casenuove (Empoli municipality, Tuscany, Italy) comprising various shells of Chelonibia testudinaria associated to a partial skeleton of a balaenid mysticete. Based on taphonomic and morpho-functional considerations, we discuss the hypothesis that the barnacles were hosted on the baleen whale, possibly on its callosities, which could have represented an analogous of the horny carapace of marine turtles. This record strongly suggests that the baleen whales can be added to the list of the possible hosts of the barnacles of the genus Chelonibia, thus hinting that the whale barnacles may have evolved from an ancient phase of dispersal of Chelonibia (or a similar ancestor) on mysticete cetaceans
A PLIOCENE GRAY WHALE (ESCHRICHTIUS SP.) FROM THE EASTERN NORTH ATLANTIC
The gray whale Eschrichtius robustus, the only living member of the eschrichtiid lineage, currently inhabits only the North Pacific. Interestingly, however, the holotypes of both E. robustus and the late Miocene Archaeschrichtius ruggieroi (the oldest known eschrichtiid species) come from the North Atlantic and the Mediterranean, respectively. Here we describe a partial mysticete mandible from the Pliocene (3.71â2.76 Ma) of Belgium (Eastern North Atlantic). This new fossil displays a combination of morphological features that makes it nearly identical to modern E. robustus. Nevertheless, given its incomplete nature, the studied specimen is here identified in open nomenclature as belonging to Eschrichtius sp. The recognition of such an early record of Eschrichtius in the North Atlantic suggests that this genus developed a circum-Northern Hemisphere distribution not later than in Pliocene times, thus complicating our understanding of its origin, evolutionary history, and palaeobiogeographic patterns
A new balaenopterid species from the Southern North Sea Basin informs about phylogeny and taxonomy of Burtinopsis and Protororqualus (Cetacea, Mysticeti, Balaenopteridae)
Background An extensive radiation can be inferred among balaenopterid mysticetes in the last 10 million years based on a rich fossil record. Many extinct genera and species have been established in the past by the study of fossil rorquals from northern and southern hemispheres. In many cases, the new fossils are used to create new genera. However, in very recent times, new species of known genera have been described that help our understanding of the speciation processes and the biogeography of these whales. Here, a new species of balaenopterid whales is described in order to better understand the past diversity of Balaenopteridae and to analyze its paleobiogeographical implications. As the new species closely resembles a taxon established in the 19th century (i.e., Burtinopsis), a detailed analysis of this taxon was necessary to support the new taxonomic statements of this article. Methods A new partial skeleton including skull and earbones is described and compared to an extended sample of living and fossil mysticete species. A phylogenetic analysis including 355 character states scored in 88 taxa was performed to understand its relationships within the genus Protororqualus, to allow paleobiogeographic inferences and to better understand the relationships of Protororqualus within Balaenopteridae. Maximum parsimony analyses of character evolution were performed to understand morphological transformations within Balaenopteridae. The revision of Burtinopsis was carried out based on detailed descriptions and comparisons of the type materials that were figured and measured. Results Protororqualus wilfriedneesi sp. nov. was established based on a comparative analysis of the skull and earbone morphology. The specimen is dated back to the Zanclean (Lower Pliocene, between c. 5.3 and 3.6 Ma). A taphonomical study of the holotype skeleton revealed evidence of interactions with sharks and fishes before the definitive burial of the carcass. Based on the phylogenetic analysis, the monophyly of the genus Protororqualus was confirmed. Protororqualus wilfriedneesi sp. nov. was more derived than Protororqualus cuvieri suggesting that it resulted from an invasion of the North Sea Basin (and the North Atlantic ocean) from the Mediterranean basin. Several specimens from western and eastern sides of the Atlantic Ocean are described that suggest that Protororqualus wilfriedneesi had a trans-Atlantic distribution in the Pliocene
Fossilwhale barnacles fromthe lower pleistocene of sicily shed light on the coevalmediterranean cetacean fauna
We report on three shells of whale barnacle (Cirripedia: Coronulidae) collected from Pleistocene shallow-marine deposits exposed at Cinisi (northwestern Sicily, southern Italy). These specimens are identified as belonging to the extinct species Coronula bifida BRONN, 1831. Calcareous nannoplankton analysis of the sediment hosting the coronulid remains places the time of deposition between 1.93 and 1.71 Ma (i.e., at the Gelasian-Calabrian transition), an interval during which another deposit rich in whale barnacles exposed in southeastern Apulia (southern Italy) formed. Since Coronula LAMARCK, 1802, is currently found inhabiting the skin of humpback whales [Cetacea: Balaenopteridae: Megaptera novaeangliae (BOROWSKI, 1781)], and considering that the detachment of extant coronulids from their hostsâ skin has been mainly observed in occurrence of cetacean breeding/calving areas, the material here studied supports the existence of a baleen whale migration route between the central Mediterranean Sea (the putative reproductive ground) and the North Atlantic (the putative feeding ground) around 1.8 Ma, when several portions of present-day southern Italy were still submerged. The early Pleistocene utilization of the epeiric seas of southern Italy as breeding/calving areas by migrating mysticetes appears to be linked to the severe climatic degradation that has been recognized at the Gelasian-Calabrian transition and that is marked in the fossil record of the Mediterranean Basin by the appearance of ânorthern guestsâ such as Arctica islandica (LINNAEUS, 1767) (Bivalvia: Veneroida). The subsequent abandonment of the Mediterranean Sea by most species of mysticetes is likely to have resulted from the progressive emergence of shallow-water coastal environments that occurred in Calabrian and Middle Pleistocene times
An introductory study of house spiders (Araneae) in Belgium
More than 800 spiders were collected in 43 houses heated in winter, distributed mainly in the northern part of Belgium. Information required for the collections to be eligible for the project was: address, construction year, type of house, and surroundings. The spiders were qualified as âhouse spidersâ or âgarden spidersâ. Of the 93 species collected, 19 could be defined as house spiders. Pholcus phalangioides was the most common, followed by Eratigena atrica and Steatoda triangulosa. Garden spiders enter the house much more often in houses in a rural environment than in those situated in clusters, and mainly in spring. The spiders are most common in autumn when many of them are breeding. The common house spiders colonize houses shortly after their construction
A large Late Miocene cetotheriid (Cetacea, Mysticeti) from the Netherlands clarifies the status of Tranatocetidae
Cetotheriidae are a group of small baleen whales (Mysticeti) that evolved alongside modern rorquals. They once enjoyed a nearly global distribution, but then largely went extinct during the Plio-Pleistocene. After languishing as a wastebasket taxon for more than a century, the concept of Cetotheriidae is now well established. Nevertheless, the clade remains notable for its variability, and its scope remains in flux. In particular, the recent referral of several traditional cetotheriids to a new and seemingly unrelated family, Tranatocetidae, has created major phylogenetic uncertainty. Here, we describe a new species of Tranatocetus, the type of Tranatocetidae, from the Late Miocene of the Netherlands. Tranatocetus maregermanicum sp. nov. clarifies several of the traits previously ascribed to this genus, and reveals distinctive auditory and mandibular morphologies suggesting cetotheriid affinities. This interpretation is supported by a large phylogenetic analysis, which mingles cetotheriids and tranatocetids within a unified clade. As a result, we suggest that both groups should be reintegrated into the single family Cetotheriidae
A vertebra of a small species of Pachycetus from the North Sea and its inner structure and vascularity compared with other basilosaurid vertebrae from the same site
In the Western Scheldt Estuary near the Belgian-Dutch border, middle to late Eocene strata crop out at the current seafloor. Most vertebrae of large Eocene basilosaurid taxa from this area were previously described in several papers. They represent three morphotypes: elongated vertebrae of a large species of Pachycetus (Morphotype 1b), a not-elongated vertebra of a large âdorudontidâ basilosaurid (Morphotype 2) and âshortenedâ vertebrae of a new, unnamed taxon (Morphotype 3). This article deals with a still undescribed, smaller vertebra, NMR-16642, from this site. Our first aim was to date it by dinoflagellate cysts in adhering sediments. Yielding an age of about 38 Ma, it is one of the very few remains of basilosaurids from Europe, of which the age could be assessed with reasonable certainty. The vertebra, Morphotype 1a, is assigned to a small species of Pachycetus. High-quality CT scans are used to differentiate between NMR-16642, Morphotype 1a, and the large species of Pachycetus, Morphotype 1b. Another aim of this paper is to investigate the inner structure and vascularity of the study vertebra and that of the other morphotypes (1b, 2, 3) from this area by using high-quality CT scans. Notwithstanding differences in size, shape and compactness, the vertebral inner structure with a multi-layered cortex of periosteal bone, surrounding two cones of endosteal bone appears to be basically similar in all morphotypes. Apparently, this inner structure reflects the ontogenetic vertebral growth. An attempt to reconstruct the vascularity of the vertebrae reveals a remarkable pattern of interconnected vascular systems. From the dorsal and, if present, ventral foramina, vascular canals are running to a central vascular node. From this node a system of vascular canals goes to the epiphyseal ends, giving rise to separate systems for cortex and cones. It is the first time that the vascularity of vertebrae of archaeocetes is investigated.</p
A vertebra of a small species of Pachycetus from the North Sea and its inner structure and vascularity compared with other basilosaurid vertebrae from the same site
In the Western Scheldt Estuary near the Belgian-Dutch border, middle to late Eocene strata crop out at the current seafloor. Most vertebrae of large Eocene basilosaurid taxa from this area were previously described in several papers. They represent three morphotypes: elongated vertebrae of a large species of Pachycetus (Morphotype 1b), a not-elongated vertebra of a large âdorudontidâ basilosaurid (Morphotype 2) and âshortenedâ vertebrae of a new, unnamed taxon (Morphotype 3). This article deals with a still undescribed, smaller vertebra, NMR-16642, from this site. Our first aim was to date it by dinoflagellate cysts in adhering sediments. Yielding an age of about 38 Ma, it is one of the very few remains of basilosaurids from Europe, of which the age could be assessed with reasonable certainty. The vertebra, Morphotype 1a, is assigned to a small species of Pachycetus. High-quality CT scans are used to differentiate between NMR-16642, Morphotype 1a, and the large species of Pachycetus, Morphotype 1b. Another aim of this paper is to investigate the inner structure and vascularity of the study vertebra and that of the other morphotypes (1b, 2, 3) from this area by using high-quality CT scans. Notwithstanding differences in size, shape and compactness, the vertebral inner structure with a multi-layered cortex of periosteal bone, surrounding two cones of endosteal bone appears to be basically similar in all morphotypes. Apparently, this inner structure reflects the ontogenetic vertebral growth. An attempt to reconstruct the vascularity of the vertebrae reveals a remarkable pattern of interconnected vascular systems. From the dorsal and, if present, ventral foramina, vascular canals are running to a central vascular node. From this node a system of vascular canals goes to the epiphyseal ends, giving rise to separate systems for cortex and cones. It is the first time that the vascularity of vertebrae of archaeocetes is investigated.</p
The upper Miocene Deurne Member of the Diest Formation revisited : unexpected results from the study of a large temporary outcrop near Antwerp International Airport, Belgium
A 5.50 m thick interval of fossiliferous intensely bioturbated heterogenous glauconiferous sand of the upper Miocene Diest Formation is documented from a very large temporary outcrop just southeast of Antwerp International Airport (northern Belgium), allowing to observe lateral variations over several hundreds of meters and to collect many vertebrate and invertebrate fossils. This paper documents observations on lithology, sedimentary and post-sedimentary structures, and discusses the results of the multi-proxy analyses of the sediment (granulometry, glauconite content, clay mineralogy, Fe content and Fe3+/Fe2+ ratios), the interpretation of the trace fossil assemblage and the sedimentary structures as well as of the large-scale samplings of micro-, meso- and macrofossils. We evidence that the Diest Formation in the Antwerp area consists of two different lithological entities, and that this twofold character can be extrapolated to all previously recorded Deurne Member outcrops. A revised lithostratigraphic scheme for the Diest Formation in the Antwerp area is proposed, with the new Borsbeek member at the base and a redefmed Deurne Member at the top
The whale barnacle Cryptolepas rhachianecti (Cirripedia: Coronulidae), a phoront of the grey whale Eschrichtius robustus (Cetacea: Eschrichtiidae), from a sandy beach in The Netherlands
An isolated compartment of a whale barnacle is herein described from Recent beach deposits in Zoutelande (Walcheren, The Netherlands). This specimen is identified as belonging to the extant coronulid species Cryptolepas rhachianecti, currently known as an epizoic symbiont of the grey whale Eschrichtius robustus. This find represents the first occurrence of C. rhachianecti outside the North Pacific, and the first one as a (sub) fossil. In view of the fact that E. robustus, which is currently confined to the North Pacific, is known as a subfossil from the northeastern Atlantic between late Late Pleistocene (c. 45,000 years ago) and historical (c. 1700 AD) times, we propose a similar (late Quaternary) age for the isolated compartment. The find indicates that the extinct late Quaternary northeastern Atlantic population of E. robustus was infected by Cryptolepas rhachianecti. Our find is, therefore, compatible with the hypothesis of an ancient grey whale migration route running between the subtropical/temperate waters of the northeast Atlantic (or Mediterranean Basin), and the cold waters of the Baltic Sea (or southern Arctic Ocean), through the southern North Sea. Finally, we discuss the systematic placement of the fossil barnacle species Cryptolepas murata and propose the possibility of its removal from the genus Cryptolepas pending further investigations