Preservation of nautilid soft parts inside and outside the conch interpreted as central nervous system, eyes, and renal concrements from the Lebanese Cenomanian

Nautilid, coleoid and ammonite cephalopods preserving jaws and soft tissue remains are moderately common in the extremely fossiliferous Konservat-Lagerstätte of the Hadjoula, Haqel and Sahel Aalma region, Lebanon. We assume that hundreds of cephalopod fossils from this region with soft-tissues lie in collections worldwide. Here, we describe two specimens of Syrionautilus libanoticus (Cymatoceratidae, Nautilida, Cephalopoda) from the Cenomanian of Hadjoula. Both specimens preserve soft parts, but only one shows an imprint of the conch. The specimen without conch displays a lot of anatomical detail. We homologise the fossilised structures as remains of the digestive tract, the central nervous system, the eyes, and the mantle. Small phosphatic structures in the middle of the body chamber of the specimen with conch are tentatively interpreted as renal concrements (uroliths). The absence of any trace of arms and the hood of the specimen lacking its conch is tentatively interpreted as an indication that this is another leftover fall (pabulite), where a predator lost parts of its prey. Other interpretations such as incomplete scavenging are also conceivable

Phylogeny of Middle-Late Ordovician lituitid cephalopods based on cladistic analysis

Phylogenetic studies are rare in early Palaeozoic cephalopods. Here, we present the first cladistic analysis of the order Lituitida based on published, as well as some new, material. Three clades are recovered within the ingroup of lituitids, Sinoceras, Ancistroceras and Lituites; the former two groups correspond to the family Sinoceratidae, and the latter one to the Lituitidae. The topology shows that the Sinoceratidae represents the basal branch, while the Lituitidae represents a monophyletic, derived clade. Furthermore, we describe new material of four species (three of which are newly defined) in four genera of the order Lituitida from the well-exposed, Middle to Upper Ordovician of Hubei (South China). The described species include Lituites evolutus Fang, Chen & Zhang, Sinoceras complexum Fang sp. nov., Tyrioceras longicameratum Fang sp. nov. and Rhynchorthoceras yizanense Fang sp. nov. Tyrioceras longicameratum from South China is the first reported occurrence of Tyrioceras in China, which has significant palaeogeographical implications.Peer reviewe

‘Arm brains’ (axial nerves) of Jurassic coleoids and the evolution of coleoid neuroanatomy

Although patchy, the fossil record of coleoids bears a wealth of information on their soft part anatomy. Here, we describe remains of the axial nerve cord from both decabrachian (Acanthoteuthis, Belemnotheutis, Chondroteuthis) and octobrachian (Plesioteuthis, Proteroctopus, Vampyronassa) coleoids from the Jurassic. We discuss some hypotheses reflecting on possible evolutionary drivers behind the neuroanatomical differentiation of the coleoid arm crown. We also propose some hypotheses on potential links between habitat depth, mode of life and the evolution of the Coleoidea

Broad snouted cladoselachian with sensory specialization at the base of modern chondrichthyans

Throughout the Silurian and Devonian, cartilaginous fish successively evolved their specialized skeletal and dental characteristics, and increasingly refined their sensory systems. The Late Devonian shark taxon Maghriboselache mohamezanei gen. et sp. n. from the eastern Anti-Atlas of Morocco is known from multiple specimens preserving most of its skeletal features, which in some instances are preserved in three dimensions. Key details of the dentition, jaws, and pectoral skeleton are shared with the iconic genus Cladoselache. Phylogenetic analyses place the family Cladoselachidae as the sister group of symmoriiforms and these groups as sister group of the holocephalans. Further phylogenetic results corroborate that the initial evolutionary radiation of crown chondrichthyans occurred within or before the Late Devonian. Remarkably, this new stem holocephalan is equipped with a wide snout and large laterally separated nasal capsules: the earliest known example of this condition in the chondrichthyan and (perhaps) gnathostome record. This suggests sensory specialization approaching that of extant broad-rostrum elasmobranchs and represents a significant addition to increasingly apparent ecomorphological diversity among early chondrichthyans

Early cephalopod evolution clarified through Bayesian phylogenetic inference

Background: Despite the excellent fossil record of cephalopods, their early evolution is poorly understood. Different, partly incompatible phylogenetic hypotheses have been proposed in the past, which reflected individual author's opinions on the importance of certain characters but were not based on thorough cladistic analyses. At the same time, methods of phylogenetic inference have undergone substantial improvements. For fossil datasets, which typically only include morphological data, Bayesian inference and in particular the introduction of the fossilized birth-death model have opened new possibilities. Nevertheless, many tree topologies recovered from these new methods reflect large uncertainties, which have led to discussions on how to best summarize the information contained in the posterior set of trees. Results: We present a large, newly compiled morphological character matrix of Cambrian and Ordovician cephalopods to conduct a comprehensive phylogenetic analysis and resolve existing controversies. Our results recover three major monophyletic groups, which correspond to the previously recognized Endoceratoidea, Multiceratoidea, and Orthoceratoidea, though comprising slightly different taxa. In addition, many Cambrian and Early Ordovician representatives of the Ellesmerocerida and Plectronocerida were recovered near the root. The Ellesmerocerida is para- and polyphyletic, with some of its members recovered among the Multiceratoidea and early Endoceratoidea. These relationships are robust against modifications of the dataset. While our trees initially seem to reflect large uncertainties, these are mainly a consequence of the way clade support is measured. We show that clade posterior probabilities and tree similarity metrics often underestimate congruence between trees, especially if wildcard taxa are involved. Conclusions: Our results provide important insights into the earliest evolution of cephalopods and clarify evolutionary pathways. We provide a classification scheme that is based on a robust phylogenetic analysis. Moreover, we provide some general insights on the application of Bayesian phylogenetic inference on morphological datasets. We support earlier findings that quartet similarity metrics should be preferred over the Robinson-Foulds distance when higher-level phylogenetic relationships are of interest and propose that using a posteriori pruned maximum clade credibility trees help in assessing support for phylogenetic relationships among a set of relevant taxa, because they provide clade support values that better reflect the phylogenetic signal.Peer reviewe

Accounting for multiple ecosystem services in a simulation of land‐use decisions: Does it reduce tropical deforestation?

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decisionmaking. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests. We integrate multi-objective optimization of land allocation with an innovative approach to consider uncertainty spaces for each objective. These uncertainty spaces account for potential variability among decisionmakers, who may have different expectations about the future. When optimizing only socio-economic objectives, the model continues the past trend in deforestation (1975–2015) in the projected land-use allocation (2015–2070). Based on indicators for biomass production, carbon storage, climate and water regulation, and soil quality, we show that considering multiple ES in addition to the socio-economic objectives has heterogeneous effects on land-use allocation. It saves some natural forest if the natural forest share is below 38%, and can stop deforestation once the natural forest share drops below 10%. For landscapes with high shares of forest (38%–80% in our study), accounting for multiple ES under high uncertainty of their indicators may, however, accelerate deforestation. For such multifunctional landscapes, two main effects prevail: (a) accelerated expansion of diversified non-natural areas to elevate the levels of the indicators and (b) increased landscape diversification to maintain multiple ES, reducing the proportion of natural forest. Only when accounting for vascular plant species richness as an explicit objective in the optimization, deforestation was consistently reduced. Aiming for multifunctional landscapes may therefore conflict with the aim of reducing deforestation, which we can quantify here for the first time. Our findings are relevant for identifying types of landscapes where this conflict may arise and to better align respective policies

Antifascismo: un espacio de encuentro entre el exilio y la política nacional. El caso de Vicente Lombardo Toledano en México (1936-1945)

This article puts forward an original interpretation of antifascism, understood as a transatlantic political culture, focusing upon the case of the union leader Vicente Lombardo Toledano. Between the Spanish Civil War and the Second World War, antifascism in Mexico acquired several meanings, centred on the reinvention of the Mexican Revolution’s legacy, while benefiting from the collaboration between European antifascist exiles and local left-wing circles. Making use of novel sources, this article vindicates the key role that Mexico was then able to enjoy internationally due to its ideological commitments.Este artículo propone una lectura original del antifascismo, entendido como una cultura política trasatlántica, a partir del caso del líder sindicalista Vicente Lombardo Toledano. Se discute la evolución del significado del antifascismo en México, centrado en la recreación del legado de la Revolución Mexicana, en el período comprendido entre la Guerra Civil española y la Segunda Guerra Mundial, enfatizando la colaboración entre el exilio antifascista europeo y los círculos izquierdistas locales. A partir de varios documentos inéditos, se reivindica el protagonismo que México ejerció entonces en virtud de su compromiso ideológico

The eastern Amessoui Syncline – a hotspot for Silurian to Carboniferous cephalopod research

Introduction : The Moroccan eastern Anti-Atlas comprises two large regions with vast outcrops of Palaeozoic rocks, the Maïder and Tafilalt (HOLLARD 1967, 1970, 1974), which have become world-reknown for Palaeozoic cephalopods, trilobites, and other groups (e.g. TERMIER & TERMIER 1950; MASSA 1965). Palaeogeographically, these regions correspond to the Maïder and Tafilalt Basins, which are divided by the south-north running Tafilalt Platform (WENDT et al. 1984; WENDT 1985, 1988; BAIDDER et al. 2016). This platform was submerged throughout the Silurian to Early Carboniferous and is characterized by often condensed, highly fossiliferous sedimentary sequences. Especially the Devonian succession (Fig. 1) crops out in a series of east-west oriented synclines. The largest of which was dubbed Amessoui Syncline after the mountain Jebel Amessoui (Fig. 2). At the western end of this syncline, the Devonian succession is much thicker than in the east because it was situated on the slope toward the Maïder Basin. In the eastern half of the syncline, the Middle to Late Devonian succession is much reduced in thickness because of the position on the Tafilalt Platform. The localities El Atrous, Filon 12, Jebel Ouaoufilal, Takkat Ou El Heyene, and El Khraouia are all situated on the former platform and accordingly are rich in pelagic fossil communities, especially cephalopods. In many layers, cephalopods occur in nearly rock-forming numbers, which can be considered as Konzentratlagerstätte sensu SEILACHER (1970, 1990). Here, we provide an overview of the cephalopod occurrences in the eastern Amessoui Syncline in their stratigraphic context