Observations on the ciliary feeding mechanism of the brachiopod Crania anomala

In young Crania anomala with a trocholophe or an early schizolophe one inhalant current enters the anterior gape, filters past the single bell-shaped cirrous basket and spills out diffusely as exhalant current both anteriorly and laterally. Late schizolophe or early spirolophe forms two separate cirrous baskets which produce two separate inhalant currents: the exhalant current still diffuses out anteriorly and laterally. In later stages either one single exhalant current comes out at the anteromedial region, or three exhalant currents, including an additional one at each posterolateral region.
The roof of the visceral cavity is attached in five places to the dorsal valve of Crania to form a mantle recess, an anterior passage and two lateral passages. A hole bored through the dorsal valve into the mantle recess or the anterior passage lets out exhalant current. The palaeobiological significance of this lies in the possible use of the hole in the perforate shell valve of the siphonotretid fossil inarticulate Schizambon australis as an exhalant opening. In this species the hole leads into the mantle recess, which also communicates via a lateral passage with each posterolateral part of the mantle space.     

Discussion of the Early Devonian rhynchonellid brachiopod genus Borealirhynchia Su, 1976

The Early Devonian brachiopod genus Borealirhynchia was established by Su, 1976. Phylum Brachiopoda (Cambrian to Devonian). In: Paleontological Atlas of North China, Inner Mongolia Volume 1. Geological Publishing House Beijing, pp. 155-227 (in Chinese). It has not been previously described in detail, nor have transverse serial sections of the internal features of Borealirhynchia delerensis, the type species, been published. In this paper Borealirhynchia, along with a few species previously assigned to it, is analysed and discussed. Detailed transverse serial sections of the internal features of B.? lata Su, 1976, are provided, based on well-preserved specimens collected from the Lower Devonian strata of Dong Ujimqin Qi, northeastern Inner Mongolia. Borealirhynchia? gigantea Su, 1976 and Latonotoechia multicosta Su, 1976 are considered to be synonyms of B.? lata Su with the same external and internal characters present in all three species. Some Lower Devonian strata, in which Borealirhynchia was found and reported, from Dong Ujimqin Qi, northeastern Inner Mongolia, are fully described.     

Age and distribution of the Late Devonian brachiopod genus Dzieduszyckia Siemiradzki, 1909 in southern China

Conodont biostratigraphical work was done at four sections recently found with occurrence of the rhynchonellide brachiopod genus, Dzieduszyckia Siemiradzki, in southern Guangxi and in the border area between Dushan County of Guizhou and Nandan County of Guangxi, South China. These sections represent two different types of facies, i.e., carbonate platform and intraplatform basin. The conodont analysis reveals that this genus occurs in the Upper triangularis Zone and the Middle crepida Zone at the Dazhai Section, through the Lower to Upper crepida zones at Dalong, and is restricted within the Upper rhomboidea Zone at the two intraplatform basin sections (Changtang and Duli). This result demonstrates that the occurrence of these peculiar rhynchonellide brachiopods in South China, regardless of the depositional environments, is within the Lower Famennian instead of the previously suggested Upper Famennian. Furthermore, this brachiopod genus in South China began to inhabit on the carbonate platform almost since the beginning of the Famennian and did not extend to the intraplatform basin facies until the late Early Famennian.Available biostratigraphic data indicate that during the Early and Middle Famennian, Dzieduszyckia is widely distributed not only in South China, but also throughout the world, such as Morocco and southern Ural.Observation on the new collections from the four studied sections reveals that the peculiar rhynchonellide brachiopods have a great morphological variation within each section. Significant differences existed among the collections from different sedimentary settings and localities, probably reflecting the environmental and geographic constraint on the morphology of Dzieduszyckia. Samples from different layers in the same section have nearly identical morphological variation, suggesting the temporal inheritance in morphology of the rhynchonellide brachiopod.     

中华真地鳖低龄若虫消化道结构及取食习性

解剖喂食不同饲料中华真地鳖EupolyphagasinensisWalker的低龄若虫 ,结果表明 ,低龄若虫消化道与成虫消化道结构相同 ,具有胃盲囊和马氏管 ;嗉囊、中肠和后肠分别占消化道总长的比率与中龄若虫相同 ,具有消化食物的能力。观察消化道各部分的滞留物变化情况 ,发现 1龄若虫取食了饲养土中的腐殖质和配合饲料 ,表明孵化后的若虫需要喂食以满足营养需要。     

Cyrtinoides Yudina and Rzhonsnitskaya, 1985, an aberrant Middle Devonian ambocoeliid brachiopod genus from China

Here we redescribe and reillustrate specimens of an ambocoeliid brachiopod previously described as Echinocoelia guangsiensis Sun, 1992 from the late Eifelian–earliest Givetian Mingtang Formation of the Liujing section in Guangxi Autonomous Region. The internal structure of the species, and especially the presence of a spondylium with tichorhinum in the ventral valve indicates that the species represents the aberrant genus Cyrtinoides Yudina and Rzhonsnitskaya, 1985. It seems probable that the anterior part of the tichorhinum in Cyrtinoides accommodated the diductor attachments. Geographic distribution of Cyrtinoides is restricted to the Northern Hemisphere and shows a disjunct pattern. This genus has not hitherto been identified from China.     

First Occurrence of the brachiopod family Erymnariidae Cooper in the Upper Cretaceous of southern Italy

The rhynchonellid family Erymnariidae Cooper includes the new genus Costerymnaria together with Erymnaria Cooper, which comprises all the known erymnariids, and Erymnaria matensis (Capasso) from the Cenomanian of the Matese Mountains in southern Italy, which is revised herein. Costerymnaria includes three new forms: Costerymnaria italica sp. nov. and Costerymnaria sp. from the Cenomanian of the Matese Mountains, and Costerymnaria apula sp. nov. from the uppermost Campanian of the Salentine Peninsula, also in southern Italy. The shell ultrastructure and mode of life together with the taphonomy of these taxa are discussed. The occurrence of these rhynchonellids extends the stratigraphical range of the family Erymnariidae, its first appearance being in the Cenomanian, and also its geographical distribution to include the southernmost part of Italy. The erymnariids are, therefore, typical Tethyan forms. Erymnaria is one of the few brachiopods to have survived the Cretaceous-Paleogene boundary events. Along with Costerymnaria it probably developed in parallel from a common ancestral stock during the Late Cretaceous.     

Cephalopod and brachiopod fossils from the Pacific: Evidence from the Upper Cretaceous of the Magellan Seamounts

Maastrichtian cephalopods and a brachiopod were dredged from the Butakov, Fedorov, Kotsebu, Il’ichev, Govorov, Gelendzhik, and Ita-Mai-Tai guyots in the Magellan Seamounts. The ammonoids Hypophylloceras sp., Phyllopachiceras sp., Anagaudryceras? sp. A, Anagaudryceras? sp. B, Gaudryceras aff. propemite Marshall, Gaudryceras sp., and Pseudophyllites cf. indra (Forbes), and the single brachiopod Basiliolidae gen. and sp. indet. are a first discovery in this oceanic region, following earlier finds of belemnites (Dimitobelus? sp., Dimitobelidae gen. and sp. nov., and Belemnitella? sp.), and two ammonoid species (Zelandites aff. japonicus Matsumoto and Tetragonitidae gen. and sp. indet.). The Late Cretaceous Magellan Seamounts dimitobelid belemnite fauna shows affinities with southern high latitude forms (New Zealand) and the ammonoid fauna with northern, middle and high latitude ones (Hokkaido-Sakhalin and/or Kamchatka). This suggests by the end of the Cretaceous major surface palaeo-currents from S and N sides in direction of the central Palaeo-Pacific, a position coinciding with the plate tectonic reconstruction of the Magellan Seamounts.     

Growth rate and substrate-related mortality of a benthic brachiopod population

Collins, M. 1991 01 15: Growth rate and substrate-related mortality of a benthic brachiopod population. Lethaia , Vol. 24, pp. 1–11. Oslo. ISSN 0024–1164.
Vital staining and careful examination of potential substrates enabled an accurate census of Terebratulina retusa to be made and prompted a study of their population dynamics. Seasonal samples of T. retusa from a deep water Modiolus -brachiopod assemblage were always dominated by small (>1 mm) individuals as growth rate of the post-larvae, estimated from changes in mean cohort length. was unexpectedly slow. Six months after settlement the animals had barely doubled in length, a rate of increase consistent with laboratory studies, but an order of magnitude less than conventional estimates. As the attainment of a size refuge is the only documented strategy by which articulate brachiopods counter overgrowth or disturbance this observation has profound implications for survival. Mortality of T. retusa in the Firth of Lorn, from different substrates, followed an unexpected pattern. Virtually the only substrate on which adult T. rehusa were recorded was the surface of M. modiolus shells, although juvenile T. retusa attached to this substrate suffered enhanced levels of mortality. Grazing pressures and spatial competition, believed to be reduced on complex surfaces, may account for the elevated mortality levels of M. modiolus-attached post-larvae prior to the apparent size refuge at a length of 2 mm. * Brachiopoda, Terebratulina, growth rate, disturbance, ecology, population structure .     

The genus Luppovia and the phylogeny of Cretaceous heteromorphic ammonoids

The unique preservation of heteromorphic shells of Luppovia Kakabadze, Bogdanova & Mikhailova 1978 from the Aptian deposits of Bolshoj Balkhan (western Turkmenia) made it possible to study the microstructure, internal shell characteristics and suture ontogeny of this genus. Microstructural investigations revealed that the dorsal shell wall in Luppovia is composed of three layers in contrast to that of monomorphic ammonoids, which is single-layered. This ability of secreting different numbers of layers in monomorphs and heteromorphs demonstrates plasticity of secreting activity of the mantle epithelium. Data obtained from the study of internal shell structure and suture ontogeny have been compared. Both these methods of investigation lead to the conclusion that the genus Luppovia belongs to the order Ammonitida. The results obtained confirm the viewpoint that the Cretaceous heteromorphic superfamilies Turrilitaceae and Ancylocerataceae have independent origins and belong to two different orders, Lytoceratida and Ammonitida, respectively. □ Ammonoidea , Luppovia, shell structure, ontogeny, phylogeny, Cretaceous.     

Egg energetics, fertilization kinetics, and population structure in echinoids with facultatively feeding larvae

Larvae of marine invertebrates either arise from small eggs and feed during their development or arise from large eggs that proceed to metamorphosis sustained only from maternal provisioning. Only a few species are known to possess facultatively feeding larvae. Of about 250 echinoid species with known mode of development, only two, Brisaster latifrons and Clypeaster rosaceus, are known to develop through facultatively planktotrophic larvae. To obtain more information on this form of development and its consequences, we determined egg size and egg energetic and protein content of these two species. We found that eggs of B. latifrons resemble those of species with nonfeeding larvae in these characteristics more than those of C. rosaceus. We also compared DNA sequences of the cytochrome oxidase (COI) gene from the Caribbean C. rosaceus to those of the sympatric planktotrophic developer C. subdepressus and also to those of the eastern Pacific species C. europacificus to estimate the degree of divergence between species with different developmental modes. Comparison of COI sequences of C. rosaceus from Panama and Florida revealed that there is no geographic differentiation in this species. Cross-fertilization experiments between C. rosaceus and C. subdepressus indicated that bidirectional gametic incompatibility has evolved between the two species.     

Elosuchus,a new genus of crocodile from the Cretaceous of the North of Africa

‘Thoracosaurus’ cherifiensis Lavocat, 1955, a longirostrine from the late Lower Cretaceous of Morocco and Algeria, is attributed to Elosuchus, n. g., with another species, E. felixi n. sp., from In Abangarit (Niger), of the same age. Stolokrosuchus from the Lower Cretaceous of Niger is also referred to the new family Elosuchidae. Synapomorphies and grades are indicated for the families of ‘mesosuchian’ longirostrine crocodiles, but no synapomorphy has been found to unite the families, except perhaps for the Thalattosuchia.     

Sex expression,sex change and fruiting habit in anAcer rufinerve population

Three hundred and thirty-eight plants ofAcer rufinerve Sieb. et Zucc. were monitored in a secondary deciduous forest for 5 years in terms of their sex expression and fruiting habit. Two types of flowers, functionally male and female, were recognized. The adult population consisted of constant males, inconstants and constant females. Constant males, plants that bore exclusively male flowers throughout the study period, accounted for 87% of the adult population. Thirty-four inconstant plants (11%) changed their sex in various ways. Constant females which accounted for only 2% of the population, were significantly smaller plants than the other two morphs, and suffered greater mortality. Fruit set was consistent and generally high for plants bearing female flowers. Thirteen juvenile plants out of 17 began reproduction during the 5 years, and all became male. For inconstant plants, fluctuation in sex expression tended to be more frequent and/or greater in magnitude for smaller plants. However, there was no evidence of the directional sex transition predicted by the size advantage hypothesis. Plant health and the successional stage of the stand should be taken into account as well as resource allocation problems to explain the proximate mechanisms of sex expression.     

Genetic structure of three populations of the 'living fossil' brachiopod Lingula from Queensland, Australia

An electrophoretic survey of enzyme variation demonstrates that the genomes of three populations of the inarticulate brachiopod Lingula contain a higher level of variability than the average for marine, tropical invertebrates, and for other brachiopods. Genetic distances between populations from localities up to 1200 km apart were very small, indicating that the populations belong to a single species, L. anatina Lamarck. These data suggest that larval dispersal is capable of maintaining a homogeneous gene pool over this range. It is predicted that the dispersal mechanism is sufficiently efficacious to ensure gene-flow throughout most of the Indo-West Pacific distribution of Lingula. Further investigations of genetic distance should support the hypothesis, based on studies of adult and larval morphology, that many presently recognized species should be reassigned to L. anatina.     

Genetic diversity, population structure and phylogenetic inference among Italian Orchids of the Serapias genus assessed by AFLP molecular markers

The means by which new species arise remain a fundamental question in the Orchid family evolution. Even if the Orchid-pollinator interactions are highly specific, events of cross-hybridization in Serapias are possible and represent a central issue of the plant's evolutionary biology. Italian Orchids have a wide variety of pollination systems and highly diverse floral traits, considered as some of the main tools for activating the speciation processes. The assess of diversity in Serapias taxa and eventual phylogenetic relationships among Serapias lingua, S. parviflora, S. vomeracea, S. apulica, S. nurrica, S. neglecta, S. cordigera, S. politisii, and some putative inter-specific hybrids were investigated at the DNA level by AFLP markers. The present molecular study on Serapias populations (1) confirms some previous finding, (2) opens new hypotheses on the possible evolutionary and taxonomic relationships existing among the Serapias species, and (3) gives indications about the real consistence of hybrid individuals in a genus characterized by a relevant gene flow.     

跳甲属昆虫的食性及其生物学意义

跳甲属昆虫广布全世界,已知300多种,体色近似,外形差异不大,分类鉴定十分困难。但其中许多种类具特殊的食性特征,其寄主植物常是分类鉴定的向导和重要参考。作者分析了已知有寄主记录的59种跳甲的寄主,并根据其寄主范围划分为5种类型:取食多科、2科、1科多属、1科2属及1科1属,而以1科1属型为最多,占67.8%。至目前所知,其寄主范围限于双子叶植物,跳甲和寄主植物之间的对应关系是跳甲的“种”对植物的“属”。值得特别关注的是寄主植物的“种”与跳甲“亚种”之间的分化关系。成虫的取食范围大于幼虫,幼虫保持原始的取食特征。跳甲的同域物种分化可能通过食性转化而进行,食性转化可能先从成虫开始。成幼食性观察是研究寄主转移的关键。     

A brachiopod boring (Podichnus) in a Late Cretaceous oyster from a mangrove-like environment, Skåne, Sweden

A characteristic etching trace, comparable to those produced by pedicles of some Recent brachiopods, was found on a Late Cretaceous, Campanian oyster shell from a mangrove-like setting in the Åsen quarry, Sweden. The trace fossil belongs to the ichnospecies Podichnus centrifugalis Bromley & Surlyk, 1973 and is, together with a single specimen of Crania craniolaris Linnæus, 1758, the only evidence of brachiopods in the mangrove-like environment.