Maria Aleksandra Bitner

High frequency of drill holes in brachiopods from the Pliocene of Algeria and its ecological implications

The fossil record holds a wealth of ecological data, including data on biotic interactions. For example, holes in the skeletons of invertebrates produced by drilling activities of their enemies are widely used for exploring the intensity of such interactions through time because they are common and easily distinguished from non-biotic holes or holes produced by other types of interactions. Such drill holes have been described in numerous studies of Palaeozoic brachiopods but rarely in those focusing on brachiopods of the post-Palaeozoic, a striking pattern given that in the late Mesozoic and Cenozoic drilling gastropods diversified and frequencies of drilled molluscs increased dramatically. During the past several years, however, drilled brachiopods were reported in several studies of the Mesozoic and Cenozoic, suggesting that this phenomenon may be more common than has been previously assumed. Here we report on drilled brachiopods from a Pliocene locality in Algeria where 90 of 261 (34.5%) specimens of Megerlia truncata show evidence of predatory drilling. These data confirm that Cenozoic drilling frequencies of brachiopods may be locally high and, when taken together with other published data, that drilling frequencies are highly heterogeneous in space and time.

X-ray Microtomography (XMT) of Fossil Brachiopod Shell Interiors for Taxonomy

The ability to see and understand the three-dimensional structure of an investigated object plays a key role in studying fossil remains. All living organisms are formed in three-dimensions, but unfortunately fossilization processes often reduce overall shape, making it difficult to gather information about real overall appearance, functionality, and inner structure. Here, using a specimen of the brachiopod Tere bratula terebratula we demonstrate a non-destructive technique for exploring the 3-D internal structure of fossil remains. The use of tomography allows the construction of a set of transverse serial sections in the manner used by brachiopod researchers for decades.

The Upper Burdigalian (Ottnangian) brachiopod fauna from the northern coast of the Upper Marine Molasse Sea in Bavaria, Southern Germany

This study presents the first detailed description of brachiopods from the Early Miocene of the Paratethys. Six brachiopod taxa have been identified from the Late Burdigalian (Ottnangian) of the Upper Marine Molasse of Bavaria, Southern Germany. A new genus of short-looped terebratulide, Gurlarnella gen. nov. is introduced. Two species, Aphelesia winebergeri sp. nov. and Gurlarnella waltli gen. et sp. nov., are new to science. Two well-known species of the family Megathyrididae, Megathiris detruncata (GMELIN, 1791) and Argyrotheca cf. subradiata (SANDBERGER, 1863) are recorded. Two additional taxa, Lingula sp. and Terebratula? sp., are described in open nomenclature. This low diversity brachiopod assemblage is distinctly different in taxonomic composition from the brachiopod faunas from the Middle Miocene of the Paratethys, but closely resembles a Miocene assemblage described from a comparable facies on Malta. This suggests that these brachiopod assemblages are facies controlled.

Bioerosion on brachiopod shells – a Cenozoic perspective

This study describes bioerosion traces ascribed to either predation or endo- and epibiont activity in twenty assemblages from the Mediterranean region and Paratethys, spanning in age from Eocene to Recent. Statistical analysis of the distribution of bioerosion traces among genera and assemblages revealed that there is higher drilling predation intensity on smaller species. Larger species seem to be primarily affected by non-drilling predators. Greatest variety in types of bioerosion could be related to species’ ecology and body size. Both major categories of bioerosion (etchings and traces of predatory activity) vary considerably among samples. Different genera show significant differences in the frequency of different bioerosion types. Shell size seems a major factor contributing to these differences.

A parautochthonous shallow marine fauna from the Late Burdigalian (early Ottnangian) of Gurlarn (Lower Bavaria, SE Germany): Macrofaunal inventory and paleoecology

This paper describes and illustrates a diverse parautochthonous macrofauna from a single Upper Burdigalian (lower Ottnangian) horizon at Gurlarn in Lower Bavaria (SE Germany). In total, 80 different taxa are recorded in specific or open nomenclature; some 50 % of these taxa are bryozoans, followed by bivalves (16 taxa), cirripedes (7 taxa), echinoderms, corals (5 taxa each), brachiopods, fish (4 taxa each), serpulids, and gastropods (3 taxa each). The presence of additional organisms was documented by actualistic comparison based on indirect evidence such as drillholes, bite marks, and specialized growth forms of bryozoan colonies. Analysis of autand synecological indicators suggests that the fauna thrived in a near-shore shallow marine setting at a water depth of 5-20 m. Based on particular faunal elements and overall faunal composition we hypothesize that the environment is characterized by three distinct but interfingering habitats, i.e. (1) rocky slopes and boulders, (2) seagrass meadows, and (3) bryozoan meadows. Because similar, albeit less wellpreserved, faunas occur at several localities along the northern coast of the early Ottnangian Molasse Sea, the parautochthonous assemblage from Gurlarn provides an excellent example for the structure of these typical biota.

A monospecific assemblage of terebratulide brachiopods in the Upper Cretaceous seep deposits of Omagari, Hokkaido, Japan

The Campanian (Upper Cretaceous) seep carbonate at Omagari (Hokkaido, Japan) yields a monospecific association of the terebratulide brachiopod Eucalathis methanophila Bitner sp. nov. The association is the only occurrence of brachiopods known from the post-Early Cretaceous history of chemosynthesis-based communities. Unlike many earlier rhynchonellide-dominated hydrocarbon seep associations—which disappeared in Aptian times—this association is composed of chlidonophorid terebratulides. It is hypothesised here that large rhynchonellide brachiopods have been outcompeted from chemosynthesis-based associations by large chemosymbiotic bivalves (especially lucinids) and that this seep association containing numerous terebratulide brachiopods originated as a result of immigration from the background fauna settling in a seep that lacked numerous large bivalves but offered some hard substrates for brachiopod attachment. Some living chlidonophorids are known to settle around seep/vent localities or more generally in deep-water hard-substrate settings. We review occurrences of brachiopods in chemosynthesis-based associations and show that brachiopods immigrated repeatedly to seep/vent environments. Eucalathis methanophila Bitner sp. nov. represents the oldest and single Mesozoic record of the genus. The new species is similar in ornamentation to three living species, Indo-Pacific E. murrayi, eastern Atlantic E. tuberata, and Caribbean E. cubensis but differs in having a higher beak and wider loop. Additionally the studied species is nearly twice as large as E. tuberata.

MOLECULAR PHYLOGENY OF RHYNCHONELLIDE ARTICULATE BRACHIOPODS (BRACHIOPODA, RHYNCHONELLIDA)

We present here the first report based on phylogenetic analyses of small subunit (SSU/18S) and large subunit (LSU/28S) ribosomal DNA (rDNA) sequences from a wider-than-token sample of rhynchonellide articulate brachiopods, with data from 11 of ∼20 extant genera (12 species) belonging to all four extant superfamilies. Data exploration by network and saturation analyses shows that the molecular sequence data are free from major aberrations and are suitable for phylogenetic reconstruction despite the presence of large deletions in four SSU rDNA sequences. Although molecular sequence analyses cannot directly illuminate the systematics of fossils, the independent, genealogical evidence and phylogenetic inferences about extant forms that they make possible are highly relevant to paleontological systematics because they highlight the limitations of evolutionary inference from morphology. Parsimony, distance, maximum likelihood (no clock) and Bayesian (relaxed-clock) analyses all find a tree topology that disagrees strongly with the existing superfamily classification. All tested phylogenetic reconstructions agree that the taxa analyzed fall into three clades designated A1, A2, and B that reflect two major divergence events. The relaxed-clock analysis indicates that clades A and B diverged in the Paleozoic, while clades A1 and A2 reflect Permo-Triassic (and later) events. Morphological homoplasy and possible gene co-option are suggested as the main sources for the discord between the morpho-classification, the results of cladistic analyses of morphology, and the relationships reconstructed from molecular sequences. The origin, function and evolutionary implications of the deletion-bearing rhynchonellide SSU rDNA sequences are briefly discussed in relation to pseudogenes and concerted evolution in the rDNA genomic region.

Morphological analysis of phylogenetic relationships among extant rhynchonellide brachiopods

Abstract Rhynchonellida is the stratigraphically oldest and phylogenetically most basal of the extant rhynchonelliform brachiopod orders, yet phylogenetic relationships among rhynchonellides are poorly known. The fourteen named rhynchonellide superfamilies (four of which have extant representatives) were defined primarily on the basis of features of the dorsal cardinalia, particularly crural morphology, but their homology and polarity have not been investigated rigorously. Superfamily monophyly is unclear, as is the evolution of several distinctive rhynchonellide morphological features, such as crura. The purpose of this study is to investigate the phylogenetic relationships among extant rhynchonellide genera using skeletal characters, and to compare the results with the current classification, elucidating the evolution of morphological features in the process. We completed parsimony-based and Bayesian analyses using fifty-eight characters of the interior and exterior of the shell that vary among the nineteen extant genera. Our results are readily interpretable with respect to the classification, and indicate that Hemithiridoidea, Dimerelloidea, and (in some analyses) Pugnacoidea appear to be monophyletic. Species classified in Dimerelloidea and Pugnacoidea, and in certain cases Hemithiridoidea, each form derived subclades that evolve from within a paraphyletic Norelloidea at the base of each subclade. Raduliform crura appear to be the most basal, phylogenetically; five other crural morphologies evolve from the raduliform state. However, morphological characters currently uniting genera in rhynchonellide superfamilies are not clearly diagnostic and exhibit a relatively high degree of homoplasy overall, suggesting that consistency with the classification may be based on a false sense of confidence in rhynchonellide morphology to clearly elucidate evolutionary relationships. Published molecular phylogenetic hypotheses conflict with the morphological topologies, further supporting this possibility. The evolutionary trends among diagnostic characters of Recent rhynchonellides appear to reflect successive juvenilization in adult morphology in several subclades, suggesting that heterochrony may have played an important role in the evolution of the group.

First Record of Brachiopods from the Marquesas Islands, French Polynesia, South Central Pacific

ABSTRACT Two species of Recent brachiopods, Eucalathis cf. murrayi and Frenulina sanguinolenta, have been identified in the collection from the Musorstom 9 Expedition to the Marquesas Islands in 1997. They represent the first record of brachiopods from the Marquesas Islands. Both species previously have been reported from the western Pacific, and F. sanguinolenta is also known from Hawai‘i in the North Central Pacific. Presence of these species in the Marquesas extends the eastern boundary of their biogeographic range. The brachiopods from the Marquesas show very low diversity when compared with the fauna from the western Pacific, as well as with that from the Hawaiian Islands. This decrease in number of species in the Pacific from west to east is also observed in other benthic invertebrate groups.

Living Brachiopods from French Polynesia, Central Pacific, with Descriptions of Two New Species

Abstract: Six species of recent brachiopods have been identified in material collected during the French Tarasoc Expedition to the Tarava Seamounts and the Society and Tuamotu Islands, French Polynesia, in 2009. Two of them, Frenulina sanguinolenta (Gmelin, 1790) and Thecidellina maxilla (Hedley, 1899), have already been reported from the studied region. Two species, Discradisca sparselineata (Dall, 1920) and Septicollarina zezinae Bitner, 2009, are reported for the first time from French Polynesia, and two other species are described as new, Dallithyris tahitiensis Bitner, n. sp., and Annuloplatidia curiosa Bitner, n. sp., although the latter species was already recorded from French Polynesia, ascribed to a different taxon. When compared with the brachiopod fauna from the southwestern Pacific, that of French Polynesia is taxonomically depauperate, which might reflect the younger geological age of the islands of the central Pacific.