Nagler C.,Ludwig Maximilians University of Munich |
Hyzny M.,Comenius University |
Haug J.T.,Ludwig Maximilians University of Munich |
Haug J.T.,GeoBio Center
BMC Evolutionary Biology | Year: 2017
Background: Isopods (woodlice, slaters and their relatives) are common crustaceans and abundant in numerous habitats. They employ a variety of lifestyles including free-living scavengers and predators but also obligate parasites. This modern-day variability of lifestyles is not reflected in isopod fossils so far, mostly as the life habits of many fossil isopods are still unclear. A rather common group of fossil isopods is Urda (190-100 million years). Although some of the specimens of different species of Urda are considered well preserved, crucial characters for the interpretation of their lifestyle (and also of their phylogenetic position), have so far not been accessible. Results: Using up-to-date imaging methods, we here present morphological details of the mouthparts and the thoracopods of 168 million years old specimens of Urda rostrata. Mouthparts are of a sucking-piercing-type morphology, similar to the mouthparts of representatives of ectoparasitic isopods in groups such as Aegidae or Cymothoidae. The thoracopods bear strong, curved dactyli most likely for attaching to a host. Therefore, mouthpart and thoracopod morphology indicate a parasitic lifestyle of Urda rostrata. Based on morphological details, Urda seems deeply nested within the parasitic isopods of the group Cymothoida. Conclusions: Similarities to Aegidae and Cymothoidae are interpreted as ancestral characters; Urda is more closely related to Gnathiidae, which is therefore also interpreted as an ingroup of Cymothoida. With this position Urda provides crucial information for our understanding of the evolution of parasitism within isopods. Finally, the specimens reported herein represent the oldest parasitic isopods known to date. © 2017 The Author(s).
Servais T.,CNRS Evolution, Ecology, and Paleonthology Laboratory |
Martin R.E.,University of Delaware |
Nutzel A.,GeoBio Center
Review of Palaeobotany and Palynology | Year: 2016
With few exceptions, the impact of the evolution of the terrestrial biosphere on the evolution of the marine sphere has been largely ignored. So too has the resulting complementary role of marine photosynthesis and primary productivity in the evolution of atmospheric and oceanic pCO2 and pO2 in response to land–sea interactions. The Early-Middle Palaeozoic invasion of the continents by plants is considered to be responsible for major changes in the carbon cycle and changing values of pO2 and pCO2 in the atmosphere. Some authors have also related the ‘terrestrialisation process’ to the rapid Late Devonian decline of organic-walled phytoplankton (acritarch) diversity. The stratigraphical interval between the Carboniferous and early Triassic, i.e., the late Palaeozoic–Early Mesozoic, is a time period with a very low diversity of organic-walled phytoplankton, and this period was therefore considered by some authors as corresponding to a ‘Phytoplankton Blackout.’ It has been argued that the marine food web during this interval was related to the invasion of land by plants, suggesting that a reduced nutrient input to the ocean by runoff decreased the number of acritarchs and primary production in the marine realm. Subsequently, it has also been suggested that the Phanerozoic phytoplankton record can be correlated with models of pCO2 with high acritarch diversities corresponding to periods of high pCO2. Conversely, the spread of terrestrial forests may have increased weathering rates via deeper rooting, releasing increased amounts of nutrients to the oceans while also increasing atmospheric pCO2. The present paper critically reviews the proposed scenarios and discusses the possible relations between terrestrial and marine ecosystems, in particular the possible impact of the terrestrialisation process on marine phytoplankton. The known Palaeozoic fossil record of the phytoplankton is incomplete to a high degree. It consists almost entirely on the organic-walled fraction, because calcareous and siliceous phytoplankton remain almost unrecorded. In addition, the fossil record solely provides information about the diversity of cysts, but not necessarily precise data of the number and quality of the cyst-producing phytoplanktonic organisms. Taking into consideration that only few modern phytoplankton taxa produce cysts, the absence of cysts in the fossil record does not necessarily imply the absence of phytoplankton. In contrast, the presence of planktotrophic larvae of marine invertebrate organisms indicates that phytoplankton must have been present in the Late Palaeozoic oceans, and the marine trophic web did indeed not collapse in the Late Devonian. The presence and abundance of filter feeding and suspension feeding benthic organisms such as brachiopods, crinoids, sponges and corals also suggest sufficient primary production in the Late Palaeozoic seas. It can be concluded that, although the phytoplankton is largely absent from the fossil record, a ‘phytoplankton blackout’ is unrealistic. A major remaining question is to understand why the cyst production decreased after the Late Devonian and why this might be correlated to changes of pCO2. © 2015 Elsevier B.V.
Kocha A.,Leibniz Institute for Biodiversity of Animals |
Gaulke M.,GeoBio Center |
Bohme W.,Leibniz Institute for Biodiversity of Animals
Zootaxa | Year: 2010
Recently, the first part of the morphological revision of the Southeast Asian water monitor lizards of the Varanus salvator (Laurenti, 1768) species group provided a taxonomic overview over the members of this successful and widespread species complex (Koch et al. 2007). There, the Philippine taxa marmoratus, nuchalis and cumingi were reelevated to species status due to diagnostic morphological characteristics, e.g. significantly enlarged scales on the neck region. In this second part of the ongoing revision, these three species are re-investigated using additional voucher specimens and advanced statistical techniques including canonical variates analysis and principal component analysis. Our new investigations indicate that V. marmoratus represents a composite species, comprising at least three distinct taxa. Hence, the populations of the Sulu Archipelago (Tawi-Tawi Island) and those of the Palawan region are described as new species, viz. Varanus rasmusseni sp. nov. and V. palawanensis sp. nov., respectively. The allopatric island populations of V. cumingi inhabiting Samar, Leyte, and Bohol (the East Visayan subregion) show characteristic and geographically correlated colour patterns distinct from the type locality Mindanao (the second subregion of Greater Mindanao), warranting subspecific partition of this species. The new subspecies is named V. cumingi samarensis ssp. nov. In contrast, the taxonomic status of V. nuchalis remained unchanged, although this species shows some considerable variation in colour pattern. The systematic chapters are supplemented with notes about biology and conservation status. The hitherto underestimated diversity and zoogeography of Philippine water monitors is discussed in the light of Pleistocene sea level fluctuations. Finally, we introduce a scenario for the evolution and spread of Southeast Asian water monitor lizards and provide an identification key for the Philippine members of the V. salvator complex. Copyright © 2010 • Magnolia Press.
Clauss M.,University of Zürich |
Rossner G.E.,SNSB Bayerische Staatssammlung fur Palaontologie und Geologie |
Rossner G.E.,Ludwig Maximilians University of Munich |
Rossner G.E.,GeoBio Center
Annales Zoologici Fennici | Year: 2014
The omasum of pecoran ruminants (which is absent in tragulids) and shorter gestation periods in non-giraffid crown pecorans (as opposed to giraffids) could represent cases of key innovations that caused disparity in species diversity in extant ruminants. Literature suggests that the different ruminant groups inhabited similar niche spectra at different times, supporting the 'increased fitness' interpretation where a key innovation does not mainly open new niches, but allows more efficient use of existing ones. In this respect, we explored data on fossil species diversity of Afro-Eurasian ruminants from the Neogene and Quaternary. Tragulid and giraffid diversity first increased during the Early/Middle Miocene with subsequent declines, whereas bovid and cervid diversity increased distinctively. Our resulting narrative, combining digestive physiology, life history and the fossil record, thus provides an explanation for the sequence of diversity patterns in Old-World ruminants. © Finnish Zoological and Botanical Publishing Board 2014. © 2014 Finnish Zoological and Botanical Publishing Board.
Barmann E.V.,University of Cambridge |
Rossner G.E.,Bayerische Staatssammlung fur Palaontologie und Geologie |
Rossner G.E.,Ludwig Maximilians University of Munich |
Rossner G.E.,GeoBio Center |
And 3 more authors.
Molecular Phylogenetics and Evolution | Year: 2013
Antilopini (gazelles and their allies) are one of the most diverse but phylogenetically controversial groups of bovids. Here we provide a molecular phylogeny of this poorly understood taxon using combined analyses of mitochondrial (CYTB, COIII, 12S, 16S) and nuclear (KCAS, SPTBN1, PRKCI, MC1R, THYR) genes. We explore the influence of data partitioning and different analytical methods, including Bayesian inference, maximum likelihood and maximum parsimony, on the inferred relationships within Antilopini. We achieve increased resolution and support compared to previous analyses especially in the two most problematic parts of their tree. First, taxa commonly referred to as "gazelles" are recovered as paraphyletic, as the genus Gazella appears more closely related to the Indian blackbuck (Antilope cervicapra) than to the other two gazelle genera (Nanger and Eudorcas). Second, we recovered a strongly supported sister relationship between one of the dwarf antelopes (Ourebia) and the Antilopini subgroup Antilopina (Saiga, Gerenuk, Springbok, Blackbuck and gazelles). The assessment of the influence of taxon sampling, outgroup rooting, and data partitioning in Bayesian analyses helps explain the contradictory results of previous studies. © 2013 Elsevier Inc.
Nutzel A.,Geobio Center |
Nakazawa K.,28 2 Koyama Shimouchikawara cho
Journal of Systematic Palaeontology | Year: 2012
A gastropod fauna from the Permian (Capitanian) Akasaka Limestone from Japan is described. It is one of the most diverse known Permian gastropod faunas and consists of at least 74 species level taxa. Forty taxa have been identified to species level; the remainder are treated in open nomenclature because of insufficient preservation. In addition, three types of neritimorph opercula are present. One family, seven genera and 28 species are described as new by N̈utzel. New taxa are the family Araeonematidae, the genera Coeloconulus, Asamiella, Costataenia, Akasakiella, Cerithiozone, Yochelsonistylus and Permocerithium, and the species Anomphalus japonicus, Anematina parva, Araeonema panthalassica, Coeloconulus panae, Trochonodus permianus, Goniasma fortecarinata, G.? nodifera, Vebericochlis mazaevi, Costataenia hayasakai, Trypanocochlea parva, Cerithiozone ornata, Cerithioides angulatum, Stegocoelia akasakaensis, Yochelsonistylus seussae, Y. felixi, Knightella hydrobiformis, Palaeostylus? irregularis, P. attenuatus, P. minutus, P. lateapicatus, Permocerithium nudum, Protorcula permiana, Medfrazyga convexa, M. rectecostata, Acteonina koizumii, Heterosubulites fusiformis, Nanochilina japonica and Streptacis orientalis. The gastropod fauna of the Akasaka Limestone has previously been known for containing some of the largest species from the Permian and the entire Palaeozoic, with specimens as large as 40 cm. The fauna is strongly dominated by molluscs and especially by gastropods and bivalves. The dominance of these groups represents a modern aspect of this fauna. Among the gastropods, high-spired caenogastropods form the most diverse and abundant group. Most of the new gastropod genera are related to Cerithioidea and some have anterior siphonal canals. This suggests an early radiation of these caenogastropods in the Asia/Panthalassa realm. The relatively large number of new taxa suggests that gastropod faunas of this region have been poorly sampled or preservation of such faunas is only sporadic. Several of the present genera and a few species are also known from Permian deposits in China, Malaysia, and Vietnam. Some of the genera are cosmopolitan. © 2012 The Natural History Museum.
Stoger I.,Bavarian State Collection of Zoology |
Schrodl M.,Bavarian State Collection of Zoology |
Schrodl M.,GeoBio Center
Molecular Phylogenetics and Evolution | Year: 2013
The origin of molluscs among lophotrochozoan metazoans is unresolved and interclass relationships are contradictory between morphology-based, multi-locus, and recent phylogenomic analyses. Within the "Deep Metazoan Phylogeny" framework, all available molluscan mitochondrial genomes were compiled, covering 6 of 8 classes. Genomes were reannotated, and 13 protein coding genes (PCGs) were analyzed in various taxon settings, under multiple masking and coding regimes. Maximum Likelihood based methods were used for phylogenetic reconstructions. In all cases, molluscs result mixed up with lophotrochozoan outgroups, and most molluscan classes with more than single representatives available are non-monophyletic. We discuss systematic errors such as long branch attraction to cause aberrant, basal positions of fast evolving ingroups such as scaphopods, patellogastropods and, in particular, the gastropod subgroup Heterobranchia. Mitochondrial sequences analyzed either as amino acids or nucleotides may perform well in some (Cephalopoda) but not in other palaeozoic molluscan groups; they are not suitable to reconstruct deep (Cambrian) molluscan evolution.Supposedly "rare" mitochondrial genome level features have long been promoted as phylogenetically informative. In our newly annotated data set, features such as genome size, transcription on one or both strands, and certain coupled pairs of PCGs show a homoplastic, but obviously non-random distribution. Apparently congruent (but not unambiguous) signal for non-trivial subclades, e.g. for a clade composed of pteriomorph and heterodont bivalves, needs confirmation from a more comprehensive bivalve sampling. We found that larger clusters not only of PCGs but also of rRNAs and even tRNAs can bear local phylogenetic signal; adding trnG-trnE to the end of the ancestral cluster trnM-trnC-trnY-trnW-trnQ might be synapomorphic for Mollusca. Mitochondrial gene arrangement and other genome level features explored and reviewed herein thus failed as golden bullets, but are promising as additional characters or evidence supporting deep molluscan clades revealed by other data sets. A representative and dense sampling of molluscan subgroups may contribute to resolve contentious interclass relationships in the future, and is vital for exploring the evolution of especially diverse mitochondrial genomes in molluscs. © 2012 Elsevier Inc.
Teichert S.,Friedrich - Alexander - University, Erlangen - Nuremberg |
Nutzel A.,GeoBio Center
Acta Palaeontologica Polonica | Year: 2015
The tiny gastropod Coelodiscus minutus is superabundant in concretions of the Early Jurassic Posidonia Shale of South Germany which were formed under anoxic or extremely dysoxic conditions. Previous suggestions that C. minutus was a holoplanktonic organism are corroborated based on new evidence from exceptionally well-preserved specimens. The measurements of shell thickness show that the shell of Coelodiscus is very thin (mean 11 μm). In contrast to previous suggestions, the shell of Coelodiscus was not formed in three ontogenetic phases (embryonic, larval and adult shell) but in two phases comprising an embryonic and a secondary shell, the latter forming during an extended larval phase. Hostile conditions on the sea floor, absence or extreme scarcity of epibenthic animals as well as the small size also argue against a benthic life style of this gastropod. Coelodiscus minutus is the oldest known holoplanktonic gastropod. We speculate that Coelodiscus evolved during the Early Jurassic from a benthic precursor, which had a planktotrophic larval development. Probably under the influence of increasing frequency of dysoxic episodes along with hostile benthic conditions, the larval phase was extended neotenously and eventually, a holoplanktonic species evolved. During the Early Toarcian anoxic event, C. minutus was highly abundant in the plankton and dead shells rained down to the anoxic or dysoxic sea bottom. These thin and fragile shells formed an ooze similar to the pteropod ooze in the modern deep sea. The shells were preserved due to the absence or low level of deposit feeding and bioturbation as well as the formation of early diagenetic concretions. Copyright © 2015 S. Teichert and A. Nützel.
Nutzel A.,GeoBio Center
Palaeontology | Year: 2014
The shell of marine gastropods conserves and reflects early ontogeny, including embryonic and larval stages, to a high degree when compared with other marine invertebrates. Planktotrophic larval development is indicated by a small embryonic shell (size is also related to systematic placement) with little yolk followed by a multiwhorled shell formed by a free-swimming veliger larva. Basal gastropod clades (e.g. Vetigastropoda) lack planktotrophic larval development. The great majority of Late Palaeozoic and Mesozoic 'derived' marine gastropods (Neritimorpha, Caenogastropoda and Heterobranchia) with known protoconch had planktotrophic larval development. Dimensions of internal moulds of protoconchs suggest that planktotrophic larval development was largely absent in the Cambrian and evolved at the Cambrian-Ordovician transition, mainly due to increasing benthic predation. The evolution of planktotrophic larval development offered advantages and opportunities such as more effective dispersal, enhanced gene flow between populations and prevention of inbreeding. Early gastropod larval shells were openly coiled and weakly sculptured. During the Mid- and Late Palaeozoic, modern tightly coiled larval shells (commonly with strong sculpture) evolved due to increasing predation pressure in the plankton. The presence of numerous Late Palaeozoic and Triassic gastropod species with planktotrophic larval development suggests sufficient primary production although direct evidence for phytoplankton is scarce in this period. Contrary to previous suggestions, it seems unlikely that the end-Permian mass extinction selected against species with planktotrophic larval development. The molluscan classes with highest species diversity (Gastropoda and Bivalvia) are those which may have planktotrophic larval development. Extremely high diversity in such groups as Caenogastropoda or eulamellibranch bivalves is the result of high phylogenetic activity and is associated with the presence of planktotrophic veliger larvae in many members of these groups, although causality has not been shown yet. A new gastropod species and genus, Anachronistella peterwagneri, is described from the Late Triassic Cassian Formation; it is the first known Triassic gastropod with an openly coiled larval shell. © The Palaeontological Association.
Schulbert C.,Friedrich - Alexander - University, Erlangen - Nuremberg |
Nutzel A.,Geobio Center
Bulletin of Geosciences | Year: 2013
A rich gastropod fauna is decribed from the Early/Middle Jurassic boundary (late Toarcian/early Aalenian) of Franconia (N Bavaria, South Germany). It comprises 35 nominate species and additional 9 species are treated in open nomenclature. With a few exceptions, the studied material comes from the Jurensismergel and the Opalinuston formations of the Mistelgau clay pit near Bayreuth. These sediments represent marine soft bottom environments. Gastropods are the most diverse and the most abundant group of the benthic communities in the Mistelgau clay pit. Bivalves, ophiurid and crinoid ossicles as well as foraminifera are also abundant. Among the bivalves, the paper pecten Bositra buchi and the inoceramid Pseudomytiloides dubium are especially abundant. Most of the members of the benthic fauna are small (< 15 mm) or even minute. Only the bivalve Pseudomytiloides dubium, some of the vetigastropods (e.g., Pleurotomarioidea) and the family Gordenellidae (Turritelloidea and Proacirsa) attain a size larger than 2 cm. However, these large species are rare. The most abundant gastropods are the caenogastropod species Coelodiscus minutus and Toarctocera subpunctata. Both species are especially abundant in the lowermost portions of the sampled section. Towards the Aalenian, an increase in diversity can be observed. This reflects recovery from the late Pliensbachian/early Toarcian extinction event. This event was connected with early Toarcian anoxia in Central and Northern Europe including black shale deposition (Posidonienschiefer). The studied gastropod fauna lived during still impoverished but improving environmental conditions. The relatively high diversity and abundance of the benthos suggest aerobic or dysaerobic conditions, however with possible fluctuations of oxygen concentrations. The fauna was also constrained by soft bottom conditions. 12 species are described as new: Mistelgauia monarii, Hummelgauia microstriata, Jurilda zapfi Schulbert, Nützel & Gründel sp. nov., Franconicilda juliae, Carinathilda? dieneri, Conusella convexa, Cossmannina eggmaieri, Sinuarbullina? mistelgauensis, Striactaeonina waltschewi Schulbert, Nützel & Gründel sp. nov., Striactaeonina richterorum Schulbert, Nützel & Gründel sp. nov., Parvulactaeon imprimum Schulbert, Nützel & Gründel sp. nov. and Parvulactaeon inclinatum Schulbert, Nützel & Gründel sp. nov. Three genera are described as new: Hummelgauia, Mistelgauia and Franconicilda. The family Coelodiscidae Gründel&Nützel fam. nov. is described as new based on the probably holoplanktonic gastropod genus Coelodiscus.