Ischyodus bifurcatus, a new speciesof chimaeroid fish from the upper cretaceous of New Jersey

Toothplates of the ratfish Ischyodus are rather common fossils, distributed throughout the Campanian-Maestrichtian of New Jersey and Delaware although heretofore unrecognized or described. A new species of Ischyodus differs from the European species, I. thurmanniPictet & Campiche and I. dolloiLeriche, by the fusion of the median and internal posterior tritors of the mandibular apparatus. Except in rare individuals the palatine elements of I. bifurcatus do not show any fusion of their tritoral aspects. The vomerine elements show no distinctive features that could separate them from of any of the known Ischyodus species, and the dorsal fin spine is not significantly different from those of other known chimaeroid fishes, including Edaphodon, Elasmodus, Elasmodectes and Leptomylus. Ischyodus bifurcatus is erected as a new species based upon the bifurcated appearance of the fused mandibular tritors. A temporal range from late Santonian to medial Maestrichtian is indicated by occurrences in Belgium, California, Montana, Arkansas, and Delaware as well as New Jersey.     

Contribution to the molecular phylogenetic analysis of extant holocephalan fishes (Holocephali, Chimaeriformes)

Much attention has been paid to the molecular phylogeny of holocephalan fishes during recent years, but sampling was very low and not all genera were examined. This study offers an extended sampling of species from all known genera to clarify their phylogeny and to provide an estimate of the time of origin of extant holocephalan taxa. Three mitochondrial genes (cytochrome b, 12S rRNA, and 16S rRNA) were sequenced and analysed using a variety of phylogenetic methods (Bayes, maximum likelihood, and maximum parsimony). Callorhinchidae diverged from Rhinochimaeridae and Chimaeridae about 187?Ma ago. Chimaeridae and Rhinochimaeridae diverged from each other about 159?Ma ago. Within Rhinochimaeridae, Neoharriotta is the sister genus to the closely related Harriotta and Rhinochimaera. Eight species of the family Chimaeridae, belonging to the genera Hydrolagus and Chimaera, were examined. They probably had a common ancestor about 107?Ma ago and appear paraphyletic. These results indicate that the traditional morphological generic definition of the families Rhinochimaeridae and Chimaeridae has to be reinvestigated.     

Interpretation of the toothplates of chimaeroid fishes

It has been argued that the toothplates of chimaeroid fishes exhibit a mode of growth that is fundamentally different from that of other chondrichthyans. Chimaeroid toothplates are supposed to be statodont, growing from the basal surface, whereas other chondrichthyan dentitions are lyodont, growing from the lingual towards the labial surface of the jaw. That idea is shown to be mistaken, because chimaeroid toothplates grow from the lingual surface, like other chondrichthyan dentitions. The mistake resulted from confusion about the nomenclature of toothplate surfaces, and on the choice of Chimaera as a Recent model. Callorhynchus is a more appropriate model, since it is shown to exhibit a primitive toothplate conformation, with the labial and symphysial margins of the occlusal surface bounded by a descending lamina which is applied to the margin of the jaw cartilage and grows basally throughout life. The descending lamina is well developed in toothplates of the extinct chimaeroid genera Ischyodus, Pachymylus and Brachymylus, but is much reduced in all Recent genera other than Callorhynchus. A basally-growing descending lamina also bounds the labial and symphysial margins of the principal toothplates in the Mesozoic myriacanthoids and Squaloraja. The toothplates of the Palaeozoic ‘cochliodonts' are reviewed; amongst them, the chondrenchelyids are the only forms with a basally growing descending lamina. So far as the dentition and its mode of growth arc concerned, the closest Palaeozoic relatives of chimaeroids seem to be the chondrenchelyids. The only statodont (basally growing) toothplates found in the course of this work are those of ptyctodont placoderms, which are therefore unlikely to be related to any chondrichthyans. Statodonty in its original sense (failure to shed teeth) is shown to be widespread and possibly primitive in chondrichthyans. Cochliodont and chimaeroid toothplates grow in a logarithmic spiral. Toothplates of primitive chimaeroid type, with basally growing marginal descending laminae, can develop only when the constant angle of the spiral is small (less than about 35°), and when the oral surface of the jaw grows to the same logarithmic spiral.     

Holocephalan (Chondrichthyes) dental plates with hypermineralized dentine as a substitute for missing teeth through developmental plasticity

All extant holocephalans (Chimaeroidei) have lost the ability to make individual teeth, as tooth germs are not part of the embryonic development of the dental plates or of their continuous growth. Instead, a hypermineralized dentine with a unique mineral, whitlockin, is specifically distributed within a dentine framework into structures that give the dental plates their distinctive, species-specific morphology. Control of the regulation of this distribution must be cellular, with a dental epithelium initiating the first outer dentine, and via contact with ectomesenchymal tissue as the only embryonic cell type that can make dentine. Chimaeroids have three pairs of dental plates within their mouth, two in the upper jaw and one in the lower. In the genera Chimaera, Hydrolagus and Harriotta, the morphology and distribution of this whitlockin within each dental plate differs both between different plates in the same species and between species. Whitlockin structures include ovoids, rods and tritoral pads, with substantial developmental changes between these. For example, rods appear before the ovoids and result from a change in the surrounding trabecular dentine. In Harriotta, ovoids form separately from the tritoral pads, but also contribute to tritor development, while in Chimaera and Hydrolagus, tritoral pads develop from rods that later are perforated to accommodate the vasculature. Nevertheless, the position of these structures, secreted by the specialized odontoblasts (whitloblasts), appears highly regulated in all three species. These distinct morphologies are established at the aboral margin of the dental plate, with proposed involvement of the outer dentine. We observe that this outer layer forms into serially added lingual ridges, occurring on the anterior plate only. We propose that positional, structural specificity must be contained within the ectomesenchymal populations, as stem cells below the dental epithelium, and a coincidental occurrence of each lingual, serial ridge with the whitlockin structures that contribute to the wear-resistant oral surface.     

Comparative microanatomy of the branchial sieve in three sympatric cyprinid species,related to filter-feeding mechanisms

The chimaeroid holocephalian fishes are distinguished among extant chondrichthyans by the possession of three pairs of tooth plates, evergrowing and partially hypermineralized, that are not shed and replaced like the teeth of living elasmobranchs. Although derivation of the chimaeroid tooth plate from the fusion of members of a plesiomorphic chondrichthyan tooth family has been proposed, evidence for this hypothesis has been lacking. A new analysis of the development and structure of the tooth plates in Callorhinchus milii (Holocephali, Chimaeriformes) reveals the compound nature of the tooth plates in a chimaeroid fish. Each tooth plate consists of an oral and aboral territory that form independently in the embryo and maintain separate growth surfaces through life. The descending lamina on the aboral surface of the tooth plate demarcates the growth surface of the aboral territory. Comparison with the tooth plates of Chimaera monstrosa indicates that compound tooth plates may be a feature of all chimaeroids in which a descending lamina is present. The tooth plates in these fishes represent the fusion of two members of a reduced tooth family. The condition of the tooth plates in C. milii is plesiomorphic for chimaeroids and is of evolutionary significance in that it provides further evidence to support a lyodont dentition in chimaeroid fishes similar to that found in other chondrichthyans. © 1994 Wiley-Liss, Inc.     

Observations of two deep-sea chimaeroids in Icelandic waters

Long-term survey time series repeated occurrence of the deep-sea chimaeroid species small-eyed rabbitfish Hydrolagus affinis and large-eyed rabbitfish H. mirabilis have been observed at same but few locations in Icelandic waters over 23 years. For H. affinis the catch at one specific station has consisted almost exclusively of mature males over the time period. Identification of potential aggregation locations is of vital importance to natural resource management because such aggregation may render these species vulnerable to potential fishing activities.     

Vacchi's palatal organ: a widespread trait in Holocephali

A palatal organ, possibly used for food sorting and processing, has previously been identified among the vomerine toothplates of the chimaeroid Chimaera monstrosa. In this study, the palatal organ was described in six additional species, confirming it is a widespread trait among holocephalans. It is proposed that this palatal structure, which appears to differ in shape according to each chimaeroid's degree of durophagy and is not homologous to the palatal structure described in teleosts, be hereby referred to as Vacchi's organ.     

Chimaera opalescens n. sp., a new chimaeroid (Chondrichthyes: Holocephali) from the north-eastern Atlantic Ocean

A new species of chimaeroid, Chimaera opalescens n. sp., was described from 31 type specimens caught in the north-eastern Atlantic Ocean at 950-1400 m depth. This species differed from all its congeners by the combination of the following characters: body uniformly pale brown to bronze, iridescent on fresh specimens; unpaired fins brown to purple, uniformly coloured or with pale or whitish edges; iris black; claspers tripartite and divided for a third of their length, not extending beyond the pelvic fins in adults; dorsal spine equal to or shorter than first dorsal fin; ventral caudal lobe equal to or deeper than dorsal caudal lobe. Comparison of DNA sequences of the CO1 gene with those of related species supported C. opalescens n. sp. as a distinct species. Specimens of C. opalescens n. sp. were previously misidentified as Chimaera monstrosa, a species sharing a similar geographical distribution. Chimaera opalescens n. sp. lives in deeper water and is a larger-bodied species than C. monstrosa. The two species were newly exploited by deep-sea fisheries and confused under a single landing name.     

Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed,Saskatchewan, Canada

Abstract: Acid preparation of samples of a bonebed from the Cenomanian of central Canada yielded several thousand well‐preserved chondrichthyan teeth, in addition to numerous other vertebrate remains. Teeth and other remains of one species of chimaeroid, one species of hybodont shark, three species of Ptychodus, 10 species of neoselachian sharks and two species of batoid were recorded. The family Archaeolamnidae fam. nov., genera Meristodonoides gen. nov. and Telodontaspis gen. nov. and species Ptychodus rhombodus sp. nov., Telodontaspis agassizensis gen et sp. nov., Eostriatolamia paucicorrugata sp. nov., Roulletia canadensis sp. nov., Cretorectolobus robustus sp. nov. and Orectoloboides angulatus sp. nov. are described. Status of the genus Palaeoanacorax and the species Cretoxyrhina denticulata, Squalicorax curvatus and ‘Rhinobatos’incertus are discussed, and reconstructed dentitions of Archaeolamna and Roulletia presented. The fauna is of low diversity and dominated by active hunters, with many species apparently endemic to the northern Western Interior Seaway.     

Genus Paraploactis in the fauna of Vietnam with a discussion of systematics of the P. kagoshimensis-complex (Scorpaeniformes: Aploactinidae)

Material on the genus Paraploactis from the fauna of Vietnam is revised. Two species, P. obbesi and P. hongkongiensis, are registered in the fauna of Vietnam; the latter species is described in Vietnam for the first time. The adult and juvenile exemplars from three nominal species of the P. kagoshimensis-complex are described in detail, and new characters valuable for identification of the species within the complex are revealed. The possibility of an occurrence of a species related to P. hongkongiensis in the Gulf of Siam is proposed. This species differs from P. hongkongiensis in the degrees of development of the interorbital crests, interorbital hollow, and teeth spot on the vomer, as well as patterns of the structure of the postcranial skeleton, and several other features. The genus Paraploactis is found in the Gulf of Siam for the first time.     

Lepidophylloides corumbataensis sp. nov. from the Guadalupian in the Paraná Basin,southern Brazil

A new species of the isoetalean leaf genus Lepidophylloides is described. This Guadalupian species from the Paraná Basin, Lepidophylloides corumbataensis, found as silicified microphylls in the Corumbataí Formation in the municipality of Piracicaba, São Paulo state, in southern Brazil, is the first species of the genus to be formally described for Brazil, and possibly the first for Gondwanaland. This is also the first time that surviving palisade tissue has been found in a species of Lepidophylloides. The new species is compared to known species and shown to be distinct from all previously described from Euramerican and Cathaysian floras. The organization of the xylem in arch-like or crescent-shaped bundles suggests a relation to Cathaysian species. The close association with Lycopodiopsis derbyi stems (which have true leaf scars and must have suffered leaf abscission) suggests that they are different organs from the same species.     

Secondary metabolites from Eurotium species, Aspergillus calidoustus and A. insuetus common in Canadian homes with a review of their chemistry and biological activities

As part of studies of metabolites from fungi common in the built environment in Canadian homes, we investigated metabolites from strains of three Eurotium species, namely E. herbariorum, E. amstelodami, and E. rubrum as well as a number of isolates provisionally identified as Aspergillus ustus. The latter have been recently assigned as the new species A. insuetus and A. calidoustus. E. amstelodami produced neoechinulin A and neoechinulin B, epiheveadride, flavoglaucin, auroglaucin, and isotetrahydroauroglaucin as major metabolites. Minor metabolites included echinulin, preechinulin and neoechinulin E. E. rubrum produced all of these metabolites, but epiheveadride was detected as a minor metabolite. E. herbariorum produced cladosporin as a major metabolite, in addition to those found in E. amstelodami. This species also produced questin and neoechinulin E as minor metabolites. This is the first report of epiheveadride occurring as a natural product, and the first nonadride isolated from Eurotium species. Unlike strains from mainly infection-related samples, largely from Europe, neither ophiobolins G and H nor austins were detected in the Canadian strains of A. insuetus and A. calidoustus tested, all of which had been reported from the latter species. TMC-120 A, B, C and a sesquiterpene drimane are reported with certainty for the first time from indoor isolates, as well as two novel related methyl isoquinoline alkaloids.     

First record of the plant bug genus Paramiridius Miyamoto & Yasunaga (Heteroptera,Miridae, Mirinae) from Indochina,with descriptions of two new species from Laos

The mirine plant bug genus Paramiridius, previously known only from a single Taiwanese species, is reported from Indochinese Laos for the first time and redefined. Two additional species, Paramiridius indochinensis and Paramiridius laomontanus, are described as new to science. The female genitalic structures of the genus are documented for the first time. Habitus illustrations, figures of male genitalia, and key are provided for all three known Paramiridius species.     

Annotated checklist of the leech species diversity in the Maloe More Strait of Lake Baikal,Russia

In this paper, the very first checklist of the freshwater leeches of Maloe More Strait, a special part of Lake Baikal, is presented. It includes 14 free-living and parasitic species, of which four species belong to endemic Baikal genera – two species from Baicalobdella and one species each from Baicaloclepsis and Codonobdella. The checklist highlights six potentially new morphological species recorded for the first time in the area. The exact systematic position is stated for all leech species. Each species from the list is provided with information on taxonomic synonymy, data on its geographic distribution, and ecological characteristics. New species records are additionally provided with brief morphological characteristics and photos of their external morphology.     

A new species and record of branchial parasitic isopods (Crustacea: Isopoda: Bopyridae: Pseudioninae) of porcellanid crabs from the Philippines

Branchial bopyrids infesting porcellanid crabs from the Philippines were investigated based on intertidal collections made in 1999-2000. Crabs of the genus Petrolisthes collected from sites in the northern Philippines were examined and two parasite species were found. One new pseudionine species found infesting Petrolisthes sp. [cf. Petrolisthes asiaticus (Leach)] is described as Aporobopyrus galleonus (prevalence 6.1%); this species is distinguished from other members of the genus by a setose palp on the maxilliped of the females, barbula morphology, and male characters including the possession of pleopods. This represents the second described species of Aporobopyrus from the Philippines, and the first from porcellanid crabs. In addition, Pleurocrypta macrocephalaNierstrasz and Brender à Brandis, 1923 (originally described from Indonesia) was found infesting the same unidentified Petrolisthes sp. (prevalence 2.6%); this is the first report of the species from the Philippines.     

A new species of Elpidium (Crustacea,Ostracoda) from bromeliads in Cusuco National Park,Honduras

Passively dispersing aquatic invertebrates such as Ostracoda in restricted aquatic habitats such as bromeliads remain an intriguing observation considering the highly specialised dispersal vectors needed for efficient colonisation. Here we describe a new species of Elpidium, Elpidium merendonense sp. n., collected from bromeliads in the cloud forest from Cusuco National Park, Honduras. Elpidium merendonense sp. n. is a small to medium-sized species that can be easily distinguished from its congeners by its unique outgrowth at the posterior end of the left valve, visible especially in females. The species was common all through the park occurring at a wide range of altitudes and in different species of bromeliads. This finding is the first freshwater ostracod species described from Honduras and is in agreement with the prediction that the genus Elpidium contains a large number of species with small geographic distributions. We update the list of described species of Elpidium and present a key to species.     

A new gobiid fish,Fusigobius signipinnis,from the western tropical Pacific

An undescribed goby has been collected from several localities in the western troplcal Pacific, from Japan to Australia. This species is described as a new species,Fusigobius signiplnnis. It differs from other species ofFusigobius in pectoral ray counts, colouration, largely separate pelvic fins, and shape of the first dorsal fin. The species is found in groups on sand, frequently flicking its first dorsal fin. Males are larger than females in mean size. Sex ratios are uneven, and females are twice as numerous as males.