Carlos Martínez-Pérez

Open data and digital morphology

Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully achieved. The underlying datasets for many published studies are not readily or freely available, introducing a barrier to verification and reproducibility, and the reuse of data. There is no current agreement or policy on the amount and type of data that should be made available alongside studies that use, and in some cases are wholly reliant on, digital morphology. Here, we propose a set of recommendations for minimum standards and additional best practice for three-dimensional digital data publication, and review the issues around data storage, management and accessibility.

New data on the Lower Devonian chondrichthyan fauna from Celtiberia (Spain)

CARLOS MARTINEZ-PEREZ,1 VINCENT DUPRET,2 ESTHER MANZANARES,1 and HECTOR BOTELLA*1; department of Geology, University of Valencia, C/ Doctor Moliner, 50. CP. 46100, Burjassot, Valencia, Spain, Carlos.Martinez-PerezC^uv.es; Hector.Botella@uv.es; Esther.Manzanares@uv.es; 2Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Evolutionary Biology Centre, Uppsala University, Norbyvagen 18A 752 36, Uppsala, Sweden, vincent.dupret@ebc.uu.se

New insights into the diversity dynamics of Triassic conodonts

In this paper, we examine the diversity trends and the evolutionary patterns of Triassic conodonts through a newly powered large-scale data-set compiled directly from the primary literature. Paleodiversity dynamics analyses have been undertaken by working at the species level and using a system of time units based on biozone subdivisions for a fine temporal level resolution. The role of heterogeneous duration of taxa in diversity estimates has been evaluated through the probabilistic profiles. Results reveal three different stages in the diversity behaviour of Triassic conodonts from standing metrics delimited by two inflections at the mid-Anisian and mid-Carnian. Survivorship analysis supports this pattern. Origination–extinction metrics report a diversification pattern characterised by important fluctuations during the Lopingian–Induan (earliest Triassic), the early-middle Olenekian (Early Triassic) and the Anisian–Ladinian transitions (Middle Triassic), as well as in the early Late Triassic. In addition, two clear diversification peaks are observed in the late Carnian and in the end-Norian. Reported patterns are interpreted in the context of deep extinction and environmental instability by documenting the biological signal of the main diversification and turnover patterns observed from such records. This study emphasises the singularity behaviour of diversity trends derived from the conodont record.

Machaeracanthus goujeti n. sp. (Acanthodii) from the Lower Devonian of Spain and northwest France, with special reference to spine histology

ABSTRACT We describe here a new machaeracanthid acanthodian (Machaeracanthus goujeti n. sp.), based on isolated spines, scales and scapulocoracoids from the Lower Devonian (Lochkovian-Pragian) of the Nogueras Formation, Celtiberia, Spain. The new taxon also includes a fragmentary spine and isolated scales from the Lower Devonian of northern Spain (Palencia and Cantabrian Mountains) and western France (Saint-Céneré) originally assigned to Machaeracanthus sp. The spines of M. goujeti n. sp. comprise two morphotypes in agreement with the morphofunctional model of a pair of pectoral spines articulating with the pectoral girdle already indicated for M. hunsrueckianum Südkamp & Burrow, 2007, M. longaevus Eastman, 1907, and M. sulcatus Newberry, 1857. The morphology and size of the spines distinguish M. goujeti n. sp. from the coeval species M. bohemicus Barrande, 1872; the new species most closely resembles the younger species M. peracutus Newberry, 1857. The spines of M. goujeti n. sp. consist of trabecular and lamellar dentine layers which form the wall of the central axis (pierced by a longitudinal pulp cavity) and lateral expansions. The most superficial layer of dentine is centrifugally deposited in the complete spine; this condition is found in fin spines of some chondrichthyans and contrasts with that observed in typical acanthodian fin spines where the exserted portion is ornamented with ribs of centripetally growing dentine. Very small spines and scapulocoracoids of M. goujeti n. sp. described here, are the first report of juvenile specimens of a species of Machaeracanthus Newberry, 1857. The distal part of the juvenile spine lacks lateral expansions (keel and wing) and demonstrates the first stage in the development of the spine.

Discovery of a Lochkovian flora (Lower Devonian) in the Iberian Peninsula

ABSTRACT The Lower Devonian represents an important episode in plant life history, which was marked by the diversification of land plants. Unfortunately, remains of early Devonian plants in the Iberian Peninsula are scarce. In the present paper, we describe a small assemblage of early land plants from the Lochkovian (Lower Devonian) of the Teruel Province in Spain. The main element consists of Taeniocrada-like sterile stems that are predominandy dichotomous and ribbon-like with a narrow central strand. An unidentified fossil formed by dichotomous axes together with an uncertain globular structure were also observed. This finding increases our knowledge of the palaeogeographical distribution of early land plants.

POLYGNATHUS ROSAE N. SP. (CONODONTA) AND ITS BIOSTRATIGRAPHICAL CORRELATION POTENTIAL (LOWER EMSIAN, LOWER DEVONIAN) IN THE SPANISH CENTRAL PYRENEES

The problems around the Pragian/Emsian (P/E) boundary have been widely discussed by several authors, who have pointed out that the present Global Stratotype Section and Point (GSSP) in the Zinzilban section (Kitab Reserve, Uzbekistan), is much older than the traditional German Siegenian-Emsian boundary, a fact that considerably reduces the duration of the traditional Pragian Stage. A comprehensive conodont study of two important sections (Isabena 1 and Baliera 6) demonstrates the presence of the conodont indexes for the P/E boundary in both senses (official and traditional) in the Spanish Central Pyrenees (SCP). Within the important conodont faunas registered, the presence of a new early polygnathid species Polygnathus rosae n. sp. stands out. Its stratigraphic range in the two sections is restricted to a short interval around the traditional beginning of the Emsian Stage. This particular distribution permits direct relation between both indexes, a better characterization of the P/E boundary in the traditional German sense and increases the palaeontological knowledge of this stratigraphic interval. Conodont records in the SCP suggest that Po. rosae n. sp. could be a good local index, too. In addition, Po. rosae n. sp. represents the last known step of the lineage Po. pireneaePo. rosae n. sp., a new early polygnathid lineage that supports the early radiation of the genus around the P/E boundary.

The evolution of gigantism in active marine predators

Abstract A novel hypothesis to better understand the evolution of gigantism in active marine predators and the diversity of body sizes, feeding strategies and thermophysiologies of extinct and living aquatic vertebrates is proposed. Recent works suggest that some aspects of animal energetics can act as constraining factors for body size. Given that mass-specific metabolic rate decreases with body mass, the body size of active predators should be limited by the high metabolic demand of this feeding strategy. In this context, we propose that shifts towards higher metabolic levels can enable the same activity and feeding strategy to be maintained at bigger body sizes, offering a satisfactory explanation for the evolution of gigantism in active predators, including a vast quantity of fossil taxa. Therefore, assessing the metabolic ceilings of living aquatic vertebrates and the thermoregulatory strategies of certain key extinct groups is now crucial to define the energetic limits of predation and provide quantitative support for this model.

Lonchidion derenzii, sp. nov., a New Lonchidiid Shark (Chondrichthyes, Hybodontiforms) from the Upper Triassic of Spain, with Remarks on Lonchidiid Enameloid

http://zoobank.org/urn:lsid:zoobank.org:pub:0A620E00-7B8D-4D7C-8BEE-7063C7BA0204 Citation for this article: Manzanares, E., C. Pla, C. Martínez-Pérez, H. Ferrón, and Héctor Botella. 2016. Lonchidion derenzii, sp. nov., a new lonchidiid shark (Chondrichthyes, Hybodontiforms) from the Upper Triassic of Spain, with remarks on lonchidiid enameloid. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1253585.

A Serravallian (Middle Miocene) shark fauna from Southeastern Spain and its palaeoenvironment significance

Abstract The study of a new Serravallian (Middle Miocene) locality from the Southeastern Spain has yielded a shark assemblage characterized by microremains of at least seven taxa (Deania calcea, †Isistius triangulus, †Squaliolus cf. S. schaubi, †Paraetmopterus sp., Pristiophorus sp., Scyliorhinus sp. and a cf. Squaliformes indet) of three different orders (Squaliformes, Pristiophoriformes and Carcharhiniformes). In addition, associated macroremains have also been found, including teeth of †Cosmopolitodus hastalis, Isurus sp., Hemipristis serra, Odontaspis sp., Carcharhinus spp. and †Otodus (Megaselachus) megalodon. The assemblage contains taxa with disparate environmental preferences including not only neritic and epipelagic sharks but also an important number of meso and bathypelagic representatives. The migration of deep water taxa to shallower waters through submarine canyons/coastal upwelling is proposed as the most plausible cause for explaining the origin of such assemblage. Interestingly, the composition of the deep-water taxa here reported contrast with the chondrichthyans assemblages from the Pliocene and extant Mediterranean communities. This entails a complex biogeographic history, where the Messinian salinity crisis strongly affected the posterior evolution of the Mediterranean ecosystems but some other factors, such us the existence of anoxic events during the Quaternary, could have also played an important role.

Exploring the major depletions of conodont diversity during the Triassic

In this paper, we show that the Triassic fossil record reflects just two great depletions of conodont diversity before the Rhaetian, which occurred in the Smithian (Olenekian, Early Triassic) and in the Julian (Carnian, Late Triassic). By exploring this context, our results highlighted that they respond to different origination–extinction dynamics. Thus, while the Smithian diversity depletion can be interpreted as a consequence of elevated extinction, the Julian diversity depletion was triggered by fluctuations in origination regime. This evidence suggests that, despite the role of extinction on diversity losses, conodonts suffered crucial changes on the origination regimes during the Late Triassic which triggered these events. Notwithstanding, our results indicate that the end-Triassic diversity depletion of conodonts was produced by background extinction levels in a context of lower origination. This suggests that several biological factors, rather than a unique, environmental and/or cyclic cause, could have influenced the evolutionary history of conodonts during the Triassic.