Andrzej Baliński

Faunal Dynamics Across the Silurian—Devonian Positive Isotope Excursions (δ13C, δ18O) in Podolia, Ukraine: Comparative Analysis of the Ireviken and Klonk Events

Two global isotopic events, the early Sheinwoodian (early Wenlock) and that at the Silurian—Devonian transition, have been comprehensively studied in representative carbonate successions at Kytayhorod and Dnistrove, respectively, in Podolia, Ukraine, to compare geochemistry and biotic changes related correspondingly to the Ireviken and Klonk events. These two large-scale isotope excursions reveal different regional ecosystem tendencies. The well-defined increasing trend across the Llandovery—Wenlock boundary in siliciclastic input, redox states and, supposedly, bioproductivity, was without strict correlative relations to the major 13C enrichment event. The environmental and biotic evolution was forced by eustatic sea-level fluctuations and two-step climate change toward a glaciation episode, but strongly modified by regional epeirogeny movements due to location near the mobile Teisseyre-Törnquist Fault Zone. Thus, the global early Sheinwoodian biogeochemical perturbation was of minor depositional significance in this epeiric sea, as in many other Laurussian domains. Conversely, the Podolian sedimentary record of the Klonk Event exhibits temporal links to the abrupt &dgr;13C anomaly, overprinted by a tectonically driven deepening pulse in the crucial S–D boundary interval. This carbon cycling turnover was reflected in the regional carbonate crisis and cooling episodes, paired with a tendency towards eutrophication and recurrent oxygen deficiency, but also with major storms and possible upwelling. Faunal responses in both Podolian sections follow some characters of the Silurian pattern worldwide, as manifested by conodont changeover prior to the major early Sheinwoodian isotopic/climatic anomaly. This contrasts with the relative brachiopod and chitinozoan resistances in the course of the Ireviken Event. Also, during the Klonk Event, a moderate faunal turnover, both in benthic and pelagic groups, occurred only near the very beginning of the prolonged 13C-enriched timespan across the system boundary, possibly due to progressive dysoxia and temperature drop. The characters point to a peculiarity of the Klonk Event by comparison with the Silurian global events, and some similarity already to the succeeding Devonian transgressive/anoxic episodes.

Latest Famennian Brachiopods from Kowala, Holy Cross Mountains, Poland

Latest Famennian (UD-VI, “Strunian”) brachiopod fauna from Kowala (Kielce Region, Holy Cross Mountains, Poland) consists of eighteen species within 6 orders, eleven of them reported in open nomenclature. Characteristic taxa include: Schellwienella pauli, Aulacella interlineata, Sphenospira julii, Novaplatirostrum sauerlandense, Hadyrhyncha sp., Cleiothyridina struniensis. New morphological details of Schellwienella pauli, Sphenospira julii, and Aulacella interlineata are provided. The described latest Famennian brachiopod fauna is distinctly richer than that from underlying upper Famennian deposits (11 species within 4 orders). Majority of species from Kowala seem to have been adapted to deep water settings and/or poor nutrient availability. The stratigraphic separation between Planovatirostrum in the UD-III to UD-V and Novaplatirostrum in the UD-VI observed in Sauerland and in Thuringia is valid also in the Holy Cross Mountains. This is the first comprehensive report of a relatively diversified latest Famennian brachiopod fauna from surface outcrops of Poland.

Traces of marine nematodes from 470 million years old Early Ordovician rocks in China

Summary – Cylindrical, mostly horizontal, burrows of 20-60 μm diam. and sinusoidal course, found in the middle part of the Early Ordovician (early Floian) Fenxiang Formation in the Hubei Province of China, represent the oldest record of activity by marine nematodes, preceding known nematode body fossils by 70 million years. The burrows are filled with secondarily oxidised pyrite framboids and clay mineral flakes, indicating low oxygen content in the mud and proving that the animals lined their burrows with organic matter, being bacteriovores and mud-eaters. The marine bottom environment enabling such a mode of life originated no earlier than the mid Early Cambrian (approximately 535 million years ago) owing to peristaltic bioturbation, mostly by nemathelminthans of priapulid affinities. Before the so-called ‘Agricultural Revolution’, the bottoms of shallow seas were covered with microbial mats preventing within-sediment animal life. This event imposes the lower time limit on the possible date of origin of nematodes.

First Colour-Patterned Strophomenide Brachiopod from the Earliest Devonian of Podolia, Ukraine

Retained colour pattern on the shells of Plectodonta sp. from the earliest Devonian of Podolia (Ukraine) is the first finding for strophomenide brachiopods and the oldest among articulate brachiopods. The colour pattern in Plectodonta sp. is composed of small, round, brownish spots scattered rather irregularly on the ventral valve only. This may suggest that the described pattern probably performed a protective function through disruptive camouflage against visual systems of potential predators. The occurrence of the colour pattern in Plectodonta sp. exclusively on the ventral valve strongly suggests that these brachiopods lived with the patterned (and convex) ventral valve upwards and the patternless concave dorsal valve facing to the underlying substrate. It thus contradicts a general assumption that concavo-convex brachiopods lived with their convex valves resting on the sediment.

Silicified Mississippian Brachiopods from Muhua, Southern China: Lingulids, Craniids, Strophomenids, Productids, Orthotetids, and Orthids

This paper describes 37 species (4 new) belonging to 27 genera (1 new), 14 families, and 6 orders (Lingulida, Craniida, Strophomenida, Productida, Orthotetida, and Orthida) of silicified brachiopods from the middle Tournaisian (Mississippian, lower Carboniferous) of the vicinity of Gedongguan and Muhua villages (southern China). All specimens come from acid etching of detrital and oolitic limestone lenses scattered within grey to black laminated basinal micrite and marl of the Muhua Formation. The formation, which attains about 1–10 meters in thickness, is dated to the Siphonodella crenulata Zone. More than 10,000 silicified brachiopod specimens belonging to about 70 species were recovered from over 900 kg of the sampled limestone lenses, the most diverse brachiopod fauna of that age. The characteristic feature of the studied material is the prevailing disarticulation and fragmentation of skeletal parts due to their down slope transportation into a deeper water environment. Within Lingulida, one linguloid and one discinoid species are described. Craniida are represented by five species including Nematocrania pilea sp. nov. Strophomenida are represented by fragmentarily preserved specimens belonging to one species. The most diverse are Productida, which are represented by 7 chonetidine and 12 productidine species; new are Subglobosochonetes gedongguanensis sp. nov. and Globosochonetes gracilis sp. nov. New data on morphology of larval stage of Argentiproductus margaritaceus and its mode of attachment are presented. Orthotetida is represented by 5 species including Lamellispina spinosa gen. et sp. nov. Orthida is represented by 3, mostly cosmopolitan species. This study of a middle Tournaisian brachiopod fauna from Muhua, together with published data on the Mississippian brachiopods from other regions of South China, allow to study the Devonian—Carboniferous biotic crisis and post-crisis recovery.

The Brachiopod Succession Through the Silurian—Devonian Boundary Beds at Dnistrove, Podolia, Ukraine

In the classic section across the Silurian—Devonian boundary at Dnistrove (Podolia, Ukraine) the brachiopod fauna has never been studied in detail. This paper presents results of research on brachiopods from this important locality and time interval. Bed-by-bed collecting has enabled the detailed distribution of brachiopod taxa through the boundary beds to be revealed. Generally, the reference section at Dnistrove yields rather scarce but often well preserved brachiopods. Dayla bohemica and Dnestrina gutta can be regarded as characteristic species for the uppermost Silurian. A relatively high-diversity but low-abundance brachiopod fauna occurs in the lowest 1.8 m of the earliest Devonian. Only three forms have been found to cross the Silurian—Devonian boundary: the strophomenide Plectodontu (Plectodontu) murlae puntherae subsp. nov., the atrypide Gruciunellu (Sublepida) paulula sp. nov., and the spiriferide Howellellu (Howellella) latisinuata. A relatively narrow brachiopod-rich interval at 5.5 m above the Silurian—Devonian boundary yields 16 brachiopod species which probably indicate a setting near the lower limit of the photic zone equivalent to the Benthic Assemblage 3–4 boundary. Two new species and one new subspecies are described: Skenidioides tatyunae, Plectodontu (Plectodonta) marlae puntherae, and Gruclanella (Sublepidu) paulula.

Silicified Mississippian brachiopods from Muhua, southern China: Rhynchonellides, athyridides, spiriferides, spiriferinides, and terebratulides

The second part of the monograph of the silicified brachiopod fauna from the Muhua Formation concludes with the descriptions of 36 species belonging to 32 genera and 22 families. Eighteen species are reported in open nomenclature. Two new rhynchonellide species are described: Coledium bruntoni sp. nov. and Pleuropugnoides calcaris sp. nov. The described brachiopod fauna is dominated by spiriferides (16 species), rhynchonellides (9 species), and athyridides (7 species), while spiriferinides and terebratulides are represented by 1 and 3 species, respectively. The brachiopod fauna from the Muhua Formation is characterised by remarkably high species diversity. Together with those species described in the first part of the monograph the fauna includes 69 species. The study of the brachiopod faunal dynamics during the late Famennian—late Tournaisian in southern China reveals that after a decline in the generic diversity at the Devonian—Carboniferous boundary (D—C boundary event), the Early Tournaisian brachiopod fauna shows slight impoverishment. In the middle Tournaisian the brachiopod fauna from South China shows an explosive increase in diversity on generic level which is well exemplified by the material from Muhua. The brachiopod fauna from the Muhua Formation represents a fully recovered high diversity fauna consisting of forms representing a wide spectrum of attachment strategies as well as highly specialised forms (e.g., micromorphs) adapted to special kinds of ecological niches. Numerous evidence of the biotic interaction between brachiopods and other co-occurring fauna have been revealed in the material from Muhua. These are drill holes of predatory origin, borings made on dead shells as post-mortem infestation, shell damages and malformations, and parasitic infestations.

Tubular Shell Infestations in Some Mississippian Spirilophous Brachiopods

Evidence of brachiopod shell infestation by tube dwelling parasitic-commensal organisms is very rare in the fossil record. The oldest record of this kind of biotic interaction is known as Eodiorygma acrotretophilla from the Early Cambrian phosphatic acrotretoid Linnarsonia. The youngest evidence of parasitic infestation was documented in the Early Cretaceous rhynchonellide Peregrinella multicarinata. Two other records of vermiform tubes inside brachiopod shells come from the Devonian. These are Diorygma atrypophilia, infesting Givetian atrypide shells, and Burrinjuckia spiriferidophilia, found in some Emsian spiriferides. Here we describe the fifth record of this kind of infestation for which a name Haplorygma dorsalis ichnogen. et ichnosp. nov. is proposed. The tubular infestation structure was revealed in two silicified dorsal valves of spirolophous brachiopods found in the Mississippian Muhua Formation of the Southern China. The affinity of the tube-dwelling organism is rather enigmatic, but its annelid relationship and kleptoparasitic nature seems highly probable. In addition, the phoronid affinity of Diorygma is here questioned.

Preservation of Soft Tissues in an Ordovician Linguloid Brachiopod from China

The findings of preserved soft body parts including pedicle in the linguloid brachiopods are extremely rare in the fossil record of which the early Cambrian Chengjiang (southern China) and Burgess Shale (British Columbia) faunas are the most important. However, these characteristic Cambrian soft-bodied faunas largely disappeared from the fossil record well before the end of the Cambrian. Here we describe the first record of the pedicle in a linguloid brachiopod from the post-Cambrian strata, preserved with remarkable fidelity. Contrary to the Chengjiang and Burgess Shale-type faunas which are commonly preserved as essentially two-dimensional aluminosilicate or degraded organic carbon films or pyritized compressed fossils, the specimens now recovered from the Ordovician of China show a three-dimensional, pyritized pedicle with preserved external morphology, in detail. The presence of streamlined shell shape and burrowing shell sculpture in our specimens supports an assumption for infaunal mode of life of the genus. Since all linguloid brachiopods of the early Cambrian are interpreted as epifaunal or semi-infaunal, it seems that the here described Ordovician linguloid is the oldest representative of fully infaunal brachiopods. Apparently, the long vermiform and flexible linguloid pedicle has appeared as a functionally optimized construction.

Fenxiang biota： a new Early Ordovician shallow-water fauna with soft-part preservation from China

Abstract Our perception of biodiversity in the geological past is incomplete and biased because most organisms did not have mineralized skeletons and therefore had little chance of fossilization. This especially refers to shallow-water marine environments, rarely represented by localities with exceptional preservation of fossil material (known as taphonomic windows or Konservat-Lagerstätten). Such extraordinary “windows” may markedly broaden our knowledge of biodiversity of the past. Here, we show a review of the invertebrate fossils from recently discovered locality in the Lower Ordovician Fenxiang Formation of Hubei Province in southern China revealing exceptional preservation of soft tissues. The fauna, generally of shallow-water aspect, contains linguloid brachiopods with a remarkably preserved pedicle, the oldest traces of nematode life activities, the oldest reliable record of hydroids, the first fossil antipatharian corals, a pyritized colonial organism of unknown affinity, supposed arthropod appendages, probable phosphatized scalidophoran worm embryo and other fossils. Our discovery supports the opinion that the famous soft-bodied preservation of Burgess Shale- or Chengjiang-type did not vanish from the fossil record in post-Cambrian times. The new finding represents a prelude to the Great Ordovician Biodiversification Event and provides evidence for calibration of molecular clock of several invertebrate lineages.抽象以有软躯体保存而闻名的伯吉斯页岩型或澄江型化石生物群的发现,为我们打开了一扇全面认识地质历史中生物多样性的窗口。在湖北宜昌地区新发现的早奥陶世分乡生物群就是这样的一个窗口。该动物群包括了保存有肉茎结构的舌形贝类、最早的线虫生活痕迹、最早而可靠的水螅虫化石记录、最早的黑珊瑚化石记录、一种亲缘关系不明群体生物化石、节肢动物附肢化石和可疑的scalidophoran蠕虫胚胎化石等。同时新发现为若干无脊椎动物类群分子钟的标定提供了直接的化石证据。