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Showing papers on "Genus published in 2001"



Journal ArticleDOI
TL;DR: The phylogenetic analysis suggested that Distoechodon hupeinensis might be transferred to the genus Xenocypris, the taxonomic status of the genus Plagiognathops might be preserved, and species of Xenocy Prinae and Plagiagnathops form a monophyletic group that is sister toThe genus DistoeChodon and Pseudobrama.

256 citations


Journal ArticleDOI
TL;DR: A new family, separate from the Glomaceae, is required to accommodate this group of organisms, initially named Diversisporaceae fam.

251 citations


Journal ArticleDOI
TL;DR: A phylogenetic analysis of sequences of the internal transcribed spacers of nuclear ribosomal DNA based on a worldwide sample of Piper suggested that taxa representing major geographic areas could potentially form three monophyletic groups: Asia, the South Pacific, and the Neotropics.
Abstract: With ∼1000 species distributed pantropically, the genus Piper is one of the most diverse lineages among basal angiosperms. To rigorously address the evolution of Piper we use a phylogenetic analysis of sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA based on a worldwide sample. Sequences from a total of 51 species of Piper were aligned to yield 257 phylogenetically informative sites. A single unrooted parsimony network suggested that taxa representing major geographic areas could potentially form three monophyletic groups: Asia, the South Pacific, and the Neotropics. The position of Pothomorphe was well supported among groups of New World taxa. Simultaneous phylogenetic analysis of an expanded alignment including outgroups suggested that taxa from the South Pacific and Asia formed a monophyletic group, provisionally supporting a single origin of dioecy. Within the Neotropical sister clade, resolution was high and strong bootstrap support confirmed the monophyly of several traditionally recognized infrageneric groups (e.g., Enckea [including Arctottonia], Ottonia, Radula, Macrostachys). In contrast, some of the species representing the highly polytypic subgroup Steffensia formed a clade corresponding to the previously recognized taxon Schilleria, while others were strongly associated with several of the more specialized groups of taxa. The distribution of putatively derived inflorescence and floral character states suggested that both umbellate and solitary axillary inflorescences have multiple origins. Reduction in anther number appears to be associated with highly packaged inflorescences or with larger anther primordia per flower, trends that are consistent with the suppression of later stages of androecial development.

231 citations


Journal ArticleDOI
TL;DR: The results of the present study double the known stomatopod fauna of Australian waters, now totalling 146 species and 63 genera, in 7 superfamilies and 14 families—about 50% of species and almost 74% of genera from the Indo-West Pacific.
Abstract: The Australian Stomatopod fauna is comprehensively revised. Two new genera, Belosquilla and Quollastria, are recognized. Seventy-two species are newly reported from Australia, of which 26 are described as new. Bathysquilloidea is represented by 2 genera and 3 species; Erythrosquilloidea by 1 genus and species; Eurysquilloidea by 5 genera and 8 species; Gonodactyloidea by 15 genera and 46 species; Lysiosquilloidea by 13 genera and 26 species; Parasquilloidea by 2 genera and 3 species; and Squilloidea by 25 genera and 59 species. Harpiosquillidae is synonymized with Squillidae. Gonodactylinus is synonymized with Gonodactylellus, Keijia with Carinosquilla, Raoulius with Odontodactylus, Laevosquilla with Siamosquilla and Toshimitsu with Lophosquilla. The results of the present study double the known stomatopod fauna of Australian waters, now totalling 146 species and 63 genera, in 7 superfamilies and 14 families—about 50% of species and almost 74% of genera from the Indo-West Pacific. Forty-six species (32% of the Australian fauna) are presently known only from Australia. Species richness and abundance of the Australian fauna is likely to be much greater than that implied by the composition of existing collections. Many habitats remain to be specifically targeted for stomatopods and future sampling will likely yield many more species from Australia. All Australian species are illustrated and diagnosed. Keys to the world genera and all species in Australian genera are provided.

155 citations


Journal ArticleDOI
TL;DR: It is suggested that the species definition in bacteria should be based on analysis of sequence variation in housekeeping genes, and also that the "clone" be given official status in bacterial nomenclature.

152 citations


Book ChapterDOI
01 Jan 2001
TL;DR: The definition of seagrasses at the species level is far from satisfactory in certain genera, and can cause difficulties in arriving at a correct identification, which should be careful in citing and interpreting the published literature.
Abstract: This chapter describes how the seagrass species can be identified. Seagrasses are defined as flowering plants growing in shallow marine environment. They form an ecological group and not a taxonomical one. . They are represented by twelve genera, which have been classified in diverse taxonomic groups. These are the entire families: Zosteraceae (three genera), Posidoniaceae (one genus), Cymodoceaceae (five genera), and three of the seventeen genera in the family Hydrocharitaceae. Seagrasses are aquatic plants, which have fewer morphological and anatomical features for species identification than terrestrial flowering plants. Some species have a vast geographic distribution and occupy different niches; this may result in considerable morphological variation, and some of these variations, when studied more closely, may turn out to be separate taxa. All chromosomal studies on seagrasses indicate that chromosome numbers may be different between genera and families, but that the basic numbers are similar among the different species within the same genus. Classification of the various seagrasses in the taxonomic system, and even more their phylogeny, will continue to be debated for many years to come. The definition of seagrasses at the species level is far from satisfactory in certain genera, and can cause difficulties in arriving at a correct identification. Thus, researchers should be careful in citing and interpreting the published literature, which may contain incorrect species names.

152 citations



Journal ArticleDOI
TL;DR: The level of polymorphism detected with the microsatellite loci within and among species was highly correlated with the respective mating systems, cross-pollinating species having a significantly higher gene diversity compared to self- pollinating species.
Abstract: In order to determine how informative a set of microsatellites from tomato is across the genus Lycopersicon, 17 microsatellite loci, derived from regions in and around genes, were tested on 31 accessions comprising the nine species of the genus. The microsatellite polymorphisms were used to estimate the distribution of diversity throughout the genus and to evaluate the efficacy of microsatellites for establishing species relationships in comparison with existing phylogeny reconstructions. Gene diversity and genetic distances were calculated. A high level of polymorphism was found, as well as a large number of alleles unique for species. The level of polymorphism detected with the microsatellite loci within and among species was highly correlated with the respective mating systems, cross-pollinating species having a significantly higher gene diversity compared to self-pollinating species. In general, microsatellite-based trees were consistent with a published RFLP-based dendrogram as well as with a published classification based on morphology and the mating system. A tree constructed with low-polymorphic loci (gene diversity <0.245) was shown to represent a more-reliable topology than a tree constructed with more-highly polymorphic loci.

126 citations


Journal ArticleDOI
TL;DR: This study highlights the need to understand more fully the rationale behind the rapid decline in the number of confirmed cases of tick-borne diseases in the United States.
Abstract: 1US Environmental Protection Agency, National Center for Environmental Assessment, 26 W. Martin Luther King Dr., Cincinnati, Ohio 45268 USA 2Department of Zoology, Michigan State University, East Lansing, Michigan 48824 USA 3Environmental Sciences and Resources, Portland State University, Portland, Oregon 97207 USA 4Department of Fisheries and Wildlife, Oregon State University, c/o US Environmental Protection Agency, 200 SW 35th Street, Corvallis, Oregon 97333 USA 5US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, 200 SW 35th Street, Corvallis, Oregon 97333 USA 6OAO Corporation, c/o US Environmental Protection Agency, 200 SW 35th Street, Corvallis, Oregon 97333 USA

125 citations


Journal ArticleDOI
TL;DR: Results indicate that the genus Botryosphaeria is not monophyletic, with B. vaccinii and Phyllostictavaccinii not closely related to other fungi comprising this genus and needs additional study and substantial taxonomic revision.
Abstract: Distance, parsimony and maximum likeli- hood analyses of sequence data from the internal transcribed spacers (ITS1 and ITS2) and 5.8S rDNA were used to infer the phylogenetic relationships among Botryosphaeria species and associated anamor- phic fungi. The ingroup contained 52 isolates of 16 Botryosphaeria species and related taxa. A total of 6 outgroup species from putatively related families or orders were included in the analyses. Results indicate that the genus Botryosphaeria is not monophyletic, with B. vaccinii and Phyllosticta vaccinii not closely related to other fungi comprising this genus. The main group of Botryosphaeria species and related ana- morphic fungi contains two distinct clades: one with light-colored and narrow conidia and the other with dark-colored and broader conidia. Two sections, Hy- ala and Brunnea, were proposed to represent these two groups. Botryosphaeria ribis and B. dothidea are distinct. Diplodia pinea f. sp. cupressi is different from A and B RAPD marker groups of Sphaeropsis sapinea. Placement of a species within the form genera Sphaeropsis or Diplodia does not necessarily indicate a very close relationship with other taxa within that same genus. The name B. stevensii may have been applied to more than one species. Isolates under dif- ferent species names, such as those included in the cluster containing B. quercuum, might actually be the same species. Our study indicates that the genus Bo- tryosphaeria needs additional study and substantial taxonomic revision.

Journal ArticleDOI
TL;DR: This Article is brought to you for free and open access by the Biological Sciences at ODU Digital Commons and has been accepted for inclusion in Biological Sciences Faculty Publications by an authorized administrator of ODu Digital Commons.
Abstract: This Article is brought to you for free and open access by the Biological Sciences at ODU Digital Commons. It has been accepted for inclusion in Biological Sciences Faculty Publications by an authorized administrator of ODU Digital Commons. For more information, please contact digitalcommons@odu.edu. Repository Citation Mohamed, Kamal I.; Musselman, Lytton John; and Riches, Charles R., \"The Genus Striga (Scrophulariaceae) in Africa\" (2001). Biological Sciences Faculty Publications. 189. http://digitalcommons.odu.edu/biology_fac_pubs/189

Journal ArticleDOI
TL;DR: The molecular phylogeny and the present geographic distribution of species suggested historical dispersion of the genus Anguilla according to the Tethys corridor hypothesis, which proposed that anguillid eels originated near present-day Indonesia and dispersed westward along paleo-circumglobal equatorial currents.

Journal ArticleDOI
TL;DR: This study focuses on phylogenetic relationships in two distinct species assemblages of cave‐dwelling beetles with similar disjunct distributions in the Pyrenees and Sardinia, which are believed to reflect different degrees of adaptation to cave life.
Abstract: This study focuses on phylogenetic relationships in two distinct species assemblages of cave-dwelling beetles with similar disjunct distributions in the Pyrenees and Sardinia. One assemblage contains six species in the genera Ovobathysciola (four species) and Patriziella (two species) on Sardinia and one species of Anillochlamys in the Pyrenees. Species within the two Sardinian genera co-occur in the same karst area. Although, they are believed to be each others closest relative, they have very different body types (globular body with short appendages in Ovobathysciola; elongated body with long appendages in Patriziella), which are believed to reflect different degrees of adaptation to cave life. The other assemblage of Bathysciine beetles includes three species in the genus Speonomus in the Pyrenees and one on Sardinia. All the species are rare and many are endangered. One issue of particular interest was whether Ovobathysciola and Patriziella are reciprocally monophyletic or whether each of the Patriziella species evolved independently from the co-occurring Ovobathysciola species, as the similar morphology of the Patriziella species might be due to convergence rather than common descent. Based on DNA sequences of the cytochrome oxidase I (COI) region of the mtDNA, neither scenario was supported. Rather, the two Patriziella species are sister taxa embedded within the Ovobathysciola radiation. In addition, the well-dated geological history of this region allowed us to calibrate absolute rates of COI evolution, the first such estimates for any insect. Finally this study suggests that the evolutionary acquisition of typical cave adaptations (e.g., elongated body and appendages) may occur at about the same rate as loss of traits (e.g., eyes and pigmentation) associated with cave life.

Journal ArticleDOI
TL;DR: Cretan populations are the only splendens-like taxa in addition to C. caprai that deserve subspecies status, and a monophyletic origin of all West Mediterranean and West European species emerged.

01 Jan 2001
TL;DR: A review of the specific taxonomy of the frog genus Philautus Gistel, 1848, to provide clear nomenclatural bases for future works on the phylogeny andTaxonomy of this difficult group.
Abstract: This paper is devoted to a review of the specific taxonomy of the frog genus Philautus Gistel, 1848. From 1822 to 1999, 177 nominal species were either described as members of this genus, or of other genera but subsequently referred to this genus. We tried to review the available information on the taxonomic status of these 177 names and the status of their name-bearing types. As a result of this review, 143 types are known to be extant, including 19 lectotypes and 8 neotypes designated and/or described in the present paper. In conclusion of this preliminary analysis, we provisionally distribute these 177 names in 84 valid species names in the genus Philautus, 37 invalid synonyms of the latter names, and 56 nominal species now referred to other genera. These results are highly provisional, both at specific and supraspecific levels. Additional works, using various characters and methods, will be necessary to confirm or reject the validity of a number of these species, and many additional species clearly remain to be discovered and described in the whole range of this genus. At supraspecific level, the taxonomy we use (a single genus Philautus with three subgenera) is also highly provisional, as the generic taxonomy of the whole subfamily Rhacophorinae is in strong need of revision. The present work will provide clear nomenclatural bases for future works on the phylogeny and taxonomy of this difficult group.

Journal ArticleDOI
TL;DR: The authors' phylogenetic trees indicate that the genus Petrolisthes is divided into two main clades, reflecting morphological features, and suggests an antitropical distribution; north and south temperate species form one clade and tropical species form a second clade.

Book ChapterDOI
P.H. Harvey1
01 Jan 2001
TL;DR: The most recent common ancestor of two organisms generally is not used to determine the level of the taxonomic hierarchy at which they are separated and one reason for this apparent anomaly is that systematists who originally produced the hierarchical classifications in use today ranged along an axis from lumpers to splitters.
Abstract: There is near-universal acceptance that the way organisms are classified hierarchically into species, genera, tribes, families, orders, and so on should ideally describe a hierarchy of identity by descent from common ancestors. For example, a species compared with another in the same genus would be expected to have had a more recent common ancestor than that same species compared with another from a different genus. Perfectly understandably, however, there is a general reluctance to repeatedly revise previously accepted classifications unless there is a very good reason to do so. If a classification can be shown not to reflect a hierarchy of common ancestry then that would be accepted as a good reason for change: if a species in one genus had a more recent common ancestor with a species in another genus than it did with its supposed congeners, then biologists would revise their classification. Molecular systematics has revolutionized progress in identifying the most likely correct hierarchical classification. In contrast, the date of the most recent common ancestor of two organisms generally is not used to determine the level of the taxonomic hierarchy at which they are separated. The most recent common ancestor for two species in the same genus would have been earlier in some orders than the most recent common ancestor for two species separated at the family level in other orders. One reason for this apparent anomaly is that systematists who originally produced the hierarchical classifications in use today ranged along an axis from lumpers to splitters: the former were less keen to classify species with a particular degree of morphological similarity into different higher-level taxa than were the latter.

01 Jan 2001
TL;DR: A number of Artemisia species have a high economic value for food, medicine, forage, ornamentals, and other uses, and some taxa are invasive weeds, which can adversely affect harvests.
Abstract: The genus Artemisia (Asteraceae, Anthemideae, Artemisiinae) is a large genus, one of the largest genera in its family. It is comprised of about 500 taxa at the specific or subspecific level, distributed in 5 sections or subgenera. Most species are perennial and many are landscape dominants of arid or semiarid regions. Artemisia is widely distributed in the Northern Hemisphere but poorly represented in the Southern Hemisphere. It is more richly represented in Eurasia than it is in North America. A number of Artemisia species have a high economic value for food, medicine, forage, ornamentals, and other uses. Some taxa are invasive weeds, which can adversely affect harvests.

Journal ArticleDOI
TL;DR: Any future captive breeding projects aimed at augmenting or re‐establishing populations should do so only from the appropriate source populations so as to maintain the genetic integrity of these nascent species.
Abstract: Several species of freshwater unionid mussels in the genus Lampsilis exhibit a remarkable reproductive strategy. Female mussels of these species enclose their larvae in a minnow-like lure, called a ‘superconglutinate’, to attract piscivorous fishes. When a fish attempts to ingest the superconglutinate the lure ruptures and the larvae are released to parasitize the fish. Of the four species of mussel which exhibit this strategy and are endemic to the Gulf Coast drainages of the southeastern United States, three are protected under the Endangered Species Act, and one is recognized as imperilled. Phylogenetic analysis of nucleotide sequences of the mitochondrial 16S ribosomal RNA and the first subunit of the cytochrome oxidase c genes was conducted on 18 individual specimens representing these four species and six outgroup taxa. Phylogenetic analyses of these data support the monophyly of the superconglutinate-producing mussels, and indicates a strong geographical component to the data. The zoogeographic patterns of the four taxa included in the study are congruent with those seen in freshwater vertebrates, and are consistent with a vicariant pattern resulting from fluctuations in sea level during the Pleistocene. Despite the strong geographical structuring of the data, only one species, Lampsilis subangulata , was recovered as monophyletic. The authors attribute the lack of support for the monophyly of the remaining species to insufficient sequence variation and the recent origin of the ancestor of these taxa. Based on these data, any future captive breeding projects aimed at augmenting or re-establishing populations should do so only from the appropriate source populations so as to maintain the genetic integrity of these nascent species.

Journal ArticleDOI
24 Jan 2001-Novon
TL;DR: Four new species are described and illustrated: Larnax cuyacensis from Peru, similar to L. sylvarum, but with a rotate, fleshier corolla much lighter in color, and a fruiting calyx tightly appressed to the berry.
Abstract: Based on phylogenies generated using morphological and molecular data, Deprea glabra and D. sylvarum are transferred to Larnax, and a new subspecies, L. sylvarum subsp. novogranatensis, is described. Four new species are described and illustrated: Larnax cuyacensis from Peru, similar to L. glabra and L. sylvarum, but with a rotate, fleshier corolla much lighter in color, and a fruiting calyx tightly appressed to the berry; L. grandiflora from Peru, intermediate between L. andersonii and L. sachapapa; L. parviflora from Peru, similar to L. psilophyta of Ecuador, but differing in vegetative and reproductive characters and having the smallest flowers in the genus; and L. darcyana from Colombia, similar to L. subtriflora of Peru, but differing vegetatively and with much shorter, non-branching hairs, a smaller corolla, shorter filaments, and apiculate anthers. Keys are provided for selected genera and for Larnax. In addition, some synonymies are noted.

Journal ArticleDOI
TL;DR: The monophyly of the group of species from western North America and western Eurasia provides qualified support for the Madrean-Tethyan hypothesis, which posits a Tertiary floristic connection among the semiarid regions in which these taxa occur.

Journal Article
TL;DR: Results from PAUP's analysis support the monophyly of several previously proposed species groups: alticolor, altissimus, gravenhorstii, hellmichi, kriegi, leopardinus, monticola, nigromaculatus, nigroviridis, pictus and tenuis.
Abstract: The lizard genus Liolaemus includes over 160 species of which almost half are in the chiliensis group. Although some researchers have attempted to define smaller species groups within this large clade, the relationships among the taxa within the group as a whole remain enigmatic. The objectives of this study were to (1) identify characters that will be useful for present and future phylogenetic studies of this group, and (2) generate preliminary phylogenetic hypotheses for taxa within this large clade of lizards. I examined more than 800 specimens of 73 taxa belonging to the chiliensis group from which I identified 55 phylogenetically informative morphological characters. Additional characters (6) were derived from published and unpublished data on chromosomes, life history, and ecology. Four species considered basal for the genus were taken as outgroups. A tree-building program (PAUP 4.0b2) recovered three trees of length 11.516(Retention index: 0.59). Differences found among these topologies were restrictedto the relationships of species of the elongatus group, in which monophyly was recovered in only one tree. Results from PAUP's analysis support the monophyly of several previously proposed species groups: alticolor, altissimus, gravenhorstii, hellmichi, kriegi, leopardinus, monticola, nigromaculatus, nigroviridis, pictus and tenuis. Interestingly, most of the groups indicated above are endemic to areas that have recently been described as areas of high endemism for southern South America.

Journal ArticleDOI
TL;DR: The phylogeny of Oestridae was analysed at the generic level using 118 characters from all developmental stages and including morphology, ontogeny, physiology and behaviour, and four major clades were given subfamilial rank with the phylogenetic relationship.
Abstract: Summary The phylogeny of Oestridae was analysed at the generic level using 118 characters from all developmental stages and including morphology, ontogeny, physiology and behaviour. Four major clades were given subfamilial rank with the phylogenetic relationship (Cuterebrinae (Gasterophilinae (Hypodermatinae + Oestrinae))). The subdermal parasites of the African elephant, Neocuterebra squamosa Grunberg and Ruttenia loxodontis Rodhain, had their most probable affiliation subordinate to the clade of stomach parasites, although their exact position needs further investigation. Genus Ochotonia Grunin, which is known from a single third-instar larva only, was the probable sister group of all other Hypodermatinae. Twenty-five oestrid genera were recognised as valid and those containing more than one species were defined through lists of autapomorphies. Cuterebra Clark was proposed as a senior synonym of Alouattamyia Townsend, Andinocuterebra Guimaraes, Pseudogametes Bischof and Rogenhofera Brauer. The clade of hypodermatine ungulate parasites (Hypoderma Latreille +Pallasiomyia Rubtzov +Pavlovskiata Grunin +Przhevalskiana Grunin +Strobiloestrus Brauer) remained largely unresolved, and genus Przhevalskiana emerged without defining characters.

Journal ArticleDOI
TL;DR: Previous hypotheses regarding the relationships among the American grouper species and the allied genera were evaluated by examination of mitochondrial DNA sequences of the 16S ribosomal DNA region, and maximum-parsimony criteria and neighbor-joining analysis dispute the monophyly of the American Epinephelus species.

Journal ArticleDOI
TL;DR: In Southern Europe, a number of distinct species occur allopatrically, while in Central and Eastern Europe a few species have wide distribution areas, and the composition of complexes seems to be most strongly influenced by the kind of associated species and by local history.
Abstract: Until recently, one widespread species of the genus Cobitis was thought to be present in Europe, the common spined loach Cobitis taenia. Recent studies have shown that the diversity of spined loaches is considerably higher due to (1) presence of several species as well as C. taenia and (2) presence of hybrid biotypes, living together with species. Here knowledge about distribution and diversity of spined loaches in Europe is summarized by combining original with published data. In Southern Europe, a number of distinct species occur allopatrically, while in Central and Eastern Europe a few species have wide distribution areas. Hybrid biotypes were found exclusively in Central and Eastern Europe. They were not restricted to the contact areas between the parental species, but occur in almost the entire area. In total, 15 hybrid biotypes with different genomic compositions were recorded. In the most diverse complex, four hybrid biotypes were associated with one species. In general, a syntopic occurrence of different species of Cobitis can be considered as exceptional, while the association of species with hybrid biotypes is the rule in Central and Eastern Europe. The composition of complexes seems to be most strongly influenced by the kind of associated species and by local history. Implications for conservation are (1) not to disturb the natural patterns of diversity, (2) to consider the known richness in legislation, and (3) to consider the evolutionary significance of hybrid biotypes.

Journal ArticleDOI
TL;DR: The present study provides a phylogenetic framework for an exceptional case of insular species radiation, an essential tool for unraveling the factors that have promoted this amazing diversification of spider genus Dysdera.

Journal ArticleDOI
17 Sep 2001-Bothalia
TL;DR: The plant family in the region which hasthe highest number of species and infraspecific taxa in trade is Liliaceae sensu lato .
Abstract: At least 511 medicinal plant species are traded commercially in 50 Witwatersrand umuthi shops. The plants are listedalphabetically by genus and common (vernacular) name. The orthographic vernacular names, as well as the orthographicvariations in these names, are incorporated into the list. Annotations include the plant family, the number of umuthi shopsstocking the species, the language of the common name, and the plant part traded. The plant family in the region which hasthe highest number of species and infraspecific taxa in trade is Liliaceae sensu lato ., followed in descending order by Fabaceae, Asteraceae. Euphorbiaceae and Amaryllidaceae. Approximately 88.6% of the vernacular names are in Zulu. Themean number of umuthi shops per species is 12.3. ranging from 1 to 41. Three hundred and fifty three species (69.2%) occurin the four northern provinces, and 23 species are listed as threatened on the Red Data List.

Journal ArticleDOI
TL;DR: The authors' analyses show that Calomys is constituted by two major clades, one mostly associated with mountain habitats with subsequent invasions to lowland habitats and another with species restricted to low land habitats both north and south of the Amazon basin.

Journal ArticleDOI
TL;DR: This is the first report of genetic homogeneity in a sponge species over such a large geographical distance, and shows that C. reniformis is not conspecific.
Abstract: Sponge systematics has been traditionally based on the study of the skeleton (spicules and spongin fibres). However, sponges of the genus Chondrosia are devoid of those skeletal features, making it difficult to distinguish between different species in the genus. Chondrosia reniformis Nardo, 1847, the type species of the genus, was described from the Mediterranean Sea. The lack of distinguishing morphological features may have been responsible for the widespread assignment of specimens of the genus to this species; as a result C. reniformis is considered to be a cosmopolitan species. In this work, populations of C. reniformis from the western Mediterranean (France) and the West Atlantic (Bermuda and Brazil) were analysed using allozyme electrophoresis for 13 enzyme loci. Levels of mean heterozygosity were high (Bermuda and Brazil H=0.27 and W Mediterranean H=0.12), as is often observed in sponge species. Gene identities observed between West Atlantic and Mediterranean populations were low (I=0.40–0.52, typical values for congeneric species), including the presence of four diagnostic loci. This level of divergence clearly shows that they are not conspecific. Hence, a worldwide or cosmopolitan distribution of C. reniformis would seem improbable. However, the West Atlantic samples (Bermuda and Brazil) were genetically similar (gene identity, I=0.88–0.95) over a distance of 8,000 km. This is the first report of genetic homogeneity in a sponge species over such a large geographical distance.