Molecular phylogeny and biogeography of the fern genus Pteris (Pteridaceae)

Background and Aims

Pteris (Pteridaceae), comprising over 250 species, had been thought to be a monophyletic genus until the three monotypic genera Neurocallis, Ochropteris and Platyzoma were included. However, the relationships between the type species of the genus Pteris, P. longifolia, and other species are still unknown. Furthermore, several infrageneric morphological classifications have been proposed, but are debated. To date, no worldwide phylogenetic hypothesis has been proposed for the genus, and no comprehensive biogeographical history of Pteris, crucial to understanding its cosmopolitan distribution, has been presented.

Methods

A molecular phylogeny of Pteris is presented for 135 species, based on cpDNA rbcL and matK and using maximum parsimony, maximum likelihood and Bayesian inference approaches. The inferred phylogeny was used to assess the biogeographical history of Pteris and to reconstruct the evolution of one ecological and four morphological characters commonly used for infrageneric classifications.

Key Results

The monophyly of Pteris remains uncertain, especially regarding the relationship of Pteris with Actiniopteris + Onychium and Platyzoma. Pteris comprises 11 clades supported by combinations of ecological and morphological character states, but none of the characters used in previous classifications were found to be exclusive synapomorphies. The results indicate that Pteris diversified around 47 million years ago, and when species colonized new geographical areas they generated new lineages, which are associated with morphological character transitions.

Conclusions

This first phylogeny of Pteris on a global scale and including more than half of the diversity of the genus should contribute to a new, more reliable infrageneric classification of Pteris, based not only on a few morphological characters but also on ecological traits and geographical distribution. The inferred biogeographical history highlights long-distance dispersal as a major process shaping the worldwide distribution of the species. Colonization of different niches was followed by subsequent morphological diversification. Dispersal events followed by allopatric and parapatric speciation contribute to the species diversity of Pteris.     

Adaptation and Convergent Evolution within the Jamesonia-Eriosorus Complex in High-Elevation Biodiverse Andean Hotspots

The recent uplift of the tropical Andes (since the late Pliocene or early Pleistocene) provided extensive ecological opportunity for evolutionary radiations. We test for phylogenetic and morphological evidence of adaptive radiation and convergent evolution to novel habitats (exposed, high-altitude páramo habitats) in the Andean fern genera Jamesonia and Eriosorus. We construct time-calibrated phylogenies for the Jamesonia-Eriosorus clade. We then use recent phylogenetic comparative methods to test for evolutionary transitions among habitats, associations between habitat and leaf morphology, and ecologically driven variation in the rate of morphological evolution. Páramo species (Jamesonia) display morphological adaptations consistent with convergent evolution in response to the demands of a highly exposed environment but these adaptations are associated with microhabitat use rather than the páramo per se. Species that are associated with exposed microhabitats (including Jamesonia and Eriorsorus) are characterized by many but short pinnae per frond whereas species occupying sheltered microhabitats (primarily Eriosorus) have few but long pinnae per frond. Pinnae length declines more rapidly with altitude in sheltered species. Rates of speciation are significantly higher among páramo than non-páramo lineages supporting the hypothesis of adaptation and divergence in the unique Páramo biodiversity hotspot.     

Redefinition of the Glyptonsternine genus Pareuchiloglanis (Teleostei: Sisoridae), with descriptions of three new genera

The genus Pareuchiloglanis (Sisoridae) contains 20 valid species and 5 species with uncertain taxonomic status. Previous morphological and molecular studies indicated that Pareuchiloglanis was non-monophyletic; nonetheless, no change was made to correct the taxonomy of the genus. Therefore, the authors conducted a systematic morphological comparison and molecular phylogenetic study on Pareuchiloglanis. The results showed that Pareuchiloglanis is a polyphyletic group. Species previously identified as Pareuchiloglanis can be divided into four groups, of which Pareuchiloglanis poilanei alone has the genus name Pareuchiloglanis. The remaining three groups of species are contained within new genera named Barbeuchiloglanis, Sineuchiloglanis and Tremeuchiloglanis. Each genus has a distinct distribution that does not cross or overlap. The molecular results supported the reliability of morphological classification and indicated that the four genera were not directly related to one another. Specifically, Sineuchiloglanis and Tremeuchiloglanis shared no recent common ancestor. In contrast, Sineuchiloglanis formed a sister group with Chimarrichthys, and Tremeuchiloglanis formed a sister group with Creteuchiloglanis and Pseudexostoma.     

Tropical and Temperate: Evolutionary History of Páramo Flora

Biogeography of the tropical alpine flora of South and Central America, the páramo flora, has been studied by dividing genera into tropical, temperate, and cosmopolitan chorological flora elements. Published molecular phylogenies of páramo genera are reviewed to summarize knowledge about evolutionary history of the páramo flora and to assess congruence between chorological and phylogenetic approaches. Molecular phylogenies suggest that both the tropical and temperate regions have been important source areas for evolution of the páramo flora. Conclusions derived from chorological patterns regarding origin of genera in páramo are mostly supported by phylogenetic data. Nevertheless, in Chuquiraga, Halenia, Huperzia, and Perezia the chorological scenario is rejected, and in Chusquea-Neurolepis, Elaphoglossum, Gunnera, Halenia, Jamesonia-Eriosorus, and Lasiocephalus independent colonization events from one or several source areas are suggested. Tropical and temperate genera contributed equally to modern species richness of the páramo flora. Among temperate genera, the northern hemisphere genera gave rise to more species in páramo than did genera from the southern hemisphere. So far, no unequivocal evidence has been provided for migration of páramo genera to the temperate zones.     

Morphological characterization of infra‐generic lineages in Deparia (Athyriaceae: Polypodiales)

Deparia, including the previously recognized genera Lunathyrium, Dryoathyrium (=Parathyrium), Athyriopsis, Triblemma, and Dictyodroma, is a fern genus comprising about 70 species in Athyriaceae. In this study, we inferred a robust Deparia phylogeny based on a comprehensive taxon sampling (~81% of species) that captures the morphological diversity displayed in the genus. All Deparia species formed a highly supported monophyletic group. Within Deparia, seven major clades were identified, and most of them were characterized by inferring synapomorphies using 14 morphological characters including leaf architecture, petiole base, rhizome type, soral characters, spore perine, and leaf indument. These results provided the morphological basis for an infra‐generic taxonomic revision of Deparia.     

Phylogenetic relationships of Mexican minnows of the genus Notropis (Actinopterygii, Cyprinidae)

We conducted phylogenetic analyses based on complete mitochondrial cytochrome b gene sequences among southern and central Mexican cyprinid species, included in the genera Notropis and Hybopsis. In addition 15 northern species of the genera Notropis and Hybopsis were included in the analyses in order to place the Mexican species into a larger phylogenetic framework. The phylogenetic relationships supported the existence of five major clades: (1) including species of the subgenus Alburnops of the genus Notropis plus N. shumardi; (2) species of the subgenus Notropis; (3) species of the genus Hybopsis; (4) species of the N. texanus + N. volucellus species group of the genus Notropis; (5) Mexican endemic species of the genus Notropis plus the genus Yuriria. Previous phylogenetic inferences based on morphological characters resolved the Mexican minnows analysed as N. sallaei, N. calientis, N. boucardi and Y. alta, non‐monophyletic. According to our cytochrome b evidence all Mexican minnows of the genera Notropis and Yuriria formed a monophyletic group with respect to the northern species of the genera Notropis and Hybopsis. Within the Mexican clade, three well‐supported clades were identified: the first included the closely related species N. moralesi and N. boucardi, which occur in three independent drainages of south Mexico; the second consisted of two different lineages, N. imeldae and an undescribed species of Notropis, inhabiting two independent drainages of south Mexico; the third comprised two central Mexican Notropis species (N. calientis and N. sallaei) and the Y. alta populations. Based on this study and pending a more extensive taxonomic revision of the genus Notropis, we adopt the conservative criterion of considering all Notropis species from southern and central Mexico examined, including Y. alta, as belonging to the genus Notropis. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80 , 323–337.     

Phylogeny,classification and evolution of the water scavenger beetle tribe Hydrobiusini inferred from morphology and molecules (Coleoptera: Hydrophilidae: Hydrophilinae)

The water scavenger beetle tribe Hydrobiusini contains 47 species in eight genera distributed worldwide. Most species of the tribe are aquatic, although several species are known to occur in waterfalls or tree mosses. Some members of the tribe are known to communicate via underwater stridulation. While recent morphological and molecular‐based phylogenies have affirmed the monophyly of the tribe as currently circumscribed, doubts remain about the monophyly of included genera. Here we use morphological and molecular data to infer a species‐level phylogeny of the Hydrobiusini. The monophyly of the tribe is decisively supported, as is the monophyly of most genera. The genus Hydrobius was found to be polyphyletic, and as a result the genus Limnohydrobius stat. rev. is removed from synonymy with Hydrobius, yielding three new combinations: L. melaenus comb.n. , L. orientalis comb.n. , and L. tumbius comb.n. Recent changes to the species‐level taxonomy of Hydrobius are reviewed. The morphology of the stridulatory apparatus has undergone a single remarkable transformation within the lineage, from a simple, unmodified pars stridens to one that is highly organized and complex. We present an updated key to genera, revised generic diagnoses and a list of the known distributions for all species within the tribe.     

Effect of temperature and dark pretreatment on the germination of three species of Jamesonia (Pteridaceae,Polypodiopsida)

To study the influence of temperature on the germination ability of three species of Jamesonia (Jamesonia imbricata, Jamesonia scammaniae and Jamesonia rotundifolia), spores were cultured at 10°C, 15°C and 20°C. A temperature of 15°C was selected as representative of the natural annual average temperature of the paramo environment that Jamesonia species inhabit. In addition, a dark pretreatment of 2 days was tested to verify if germination was enhanced. The results indicated that germination of Jamesonia, considering the three species as a whole, is affected by temperature, but is independent of the dark treatment. All species showed higher and faster germination at 20°C, and exhibited a threshold minimum temperature around 10°C, below which germination is avoided or extremely low and delayed. This could suggest that spore germination in Jamesonia is adapted to establish gametophyte populations during frost‐free periods.     

A polyphasic approach to the delimitation of diatom species: a case study for the genus Pinnularia (Bacillariophyta)

Diatoms are one of the most abundant and arguably the most species‐rich group of protists. Diatom species delimitation has often been based exclusively on the recognition of morphological discontinuities without investigation of other lines of evidence. Even though DNA sequences and reproductive experiments have revealed several examples of (pseudo)cryptic diversity, our understanding of diatom species boundaries and diversity remains limited. The cosmopolitan pennate raphid diatom genus Pinnularia represents one of the most taxon‐rich diatom genera. In this study, we focused on the delimitation of species in one of the major clades of the genus, the Pinnularia subgibba group, based on 105 strains from a worldwide origin. We compared genetic distances between the sequences of seven molecular markers and selected the most variable pair, the mitochondrial cox1 and nuclear encoded LSU rDNA, to formulate a primary hypothesis on the species limits using three single‐locus automated species delimitation methods. We compared the DNA‐based primary hypotheses with morphology and with other available lines of evidence. The results indicate that our data set comprised 15 species of the P. subgibba group. The vast majority of these taxa have an uncertain taxonomic identity, suggesting that several may be unknown to science and/or members of (pseudo)cryptic species complexes within the P. subgibba group.     

Phylogeny and taxonomy of the Prenolepis genus‐group of ants (Hymenoptera: Formicidae)

Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided.     

Phantoms of Gondwana?—phylogeny of the spider subfamily Mynogleninae (Araneae: Linyphiidae)

This is the first genus‐level phylogeny of the subfamily Mynogleninae. It is based on 190 morphological characters scored for 44 taxa: 37 mynoglenine taxa (ingroup) representing 15 of the 17 known genera and seven outgroup taxa representing the subfamilies Stemonyphantinae, Linyphiinae (Linyphiini and Micronetini), and Erigoninae, and a representative of the family Pimoidae, the sister‐group to Linyphiidae. No fewer than 147 of the morphological characters used in this study are new and defined for this study, and come mainly from male and female genitalia. Parsimony analysis with equal weights resulted in three most parsimonious trees of length 871. The monophyly of the subfamily Mynogleninae and the genera Novafroneta, Parafroneta, Laminafroneta, Afroneta, Promynoglenes, Metamynoglenes, and Haplinis are supported, whereas Pseudafroneta is paraphyletic. The remaining seven mynoglenine genera are either monotypic or represented by only one taxon. Diagnoses are given for all genera included in the analysis. The evolution of morphological traits is discussed and we summarize the diversity and distribution patterns of the 124 known species of mynoglenines. The preferred topology suggests a single origin of mynoglenines in New Zealand with two dispersal events to Africa, and does not support Gondwana origin.     

Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores,including one new genus and three new species

The Hippasterinae is a subfamily within the Goniasteridae, consisting of five genera and 26 species, which occur in cold‐water settings ranging from subtidal to abyssal depths. All known genera were included in a cladistic analysis resulting in two most parsimonious trees, supporting the Hippasterinae as monophyletic. Our review supports Sthenaster emmae gen. et sp. nov. as a new genus and species from the tropical Atlantic and two new Evoplosoma species, Evoplosoma claguei sp. nov. and Evoplosoma voratus sp. nov. from seamounts in the North Pacific. Hippasteria caribaea is reassigned to the genus Gilbertaster, which previously contained a single Pacific species. Our analysis supports Evoplosoma as a derived deep water lineage relative to its continental‐shelf, shallow water sister taxa. The genus Hippasteria contains approximately 15 widely distributed, but similar‐looking species, which occur in the northern and southern hemispheres. Except for Gilbertaster, at least one species in each genus has been observed or is inferred to prey on deep‐sea corals, suggesting that this lineage is important to the conservation of deep‐sea coral habitats. The Hippasterinae shares several morphological similarities with Circeaster and Calliaster, suggesting that they may be related. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 266–301.     

An integrative approach to the evolution of shrimps of the genus Palaemon (Decapoda,Palaemonidae)

Shrimps of the genus Palaemon Weber, 1795 comprise of 86 species with a wide morphological and ecological variability along the tropical and temperate regions. Studies based on molecular data have indicated that despite a recent taxonomic rearrangement, it may remain not monophyletic. On the other hand, cladistic, morphological analyses have suggested the presence of synapomorphies, implying a natural status for the genus. In this work, a broad taxonomic and molecular sampling is applied to verify whether Palaemon is a monophyletic taxon and, based on the recovered phylogeny, identify geographical and morphological patterns related to the lineages. Partial sequences of 16S rRNA, histone H3 and 18S rRNA from 60 species of Palaemon and 15 species from other genera of Palaemonidae were analysed. In addition, previously used characters as well as novel diagnostic characters were scrutinized. The present phylogeny indicates that the species of Palaemon fall into three distinct lineages and that the colonization of America and Europe likely occurred multiple times. Morphological characters allow for the identification of at least four monophyletic groups in Palaemon; two of which are monospecific at the moment. Based on the present results, it may become necessary to establish two new genera (to accommodate Palaemon concinnus and Palaemon mercedae, respectively), as well as re‐erect the genus Alaocaris Holthuis, 1949 for Palaemon antrorum, potentially including a further six American species.     

Relationships and divergence of some taxa of the subfamily Lycodinae (Zoarcidae,Pisces) based on molecular-genetic and morphological data

An integrated molecular-genetic and morphological study of 14 species of 6 genera of Zoarcidae of the subfamily Lycodinae was performed. A high coincidence of study results obtained using both methods was found. The generic independence of the genus Petroschmidtia that includes species P. albonotata and P. toyamensis was justified. It was shown that species L. schmidti and L. nigrocaudatus belong to the genus Lycogrammoides; and the generic status of the genus Bothrocarichthys with species B. microcephalus and of the genus Allolepis with species A. hollandi was restored. The studied taxa fall into three large monophyletic groups that include species of the genus Petroschmidtia, species of the genus Lycodes, and species of the genera Bothrocara, Allolepis, Bothrocarichthys, and Lycogrammoides. Taxa of the last group are characterized by a large complex of morphological differences from the first two groups, including the absence of ventral fins. A key to species and genera of Lycogrammoides and Bothrocarichthys was compiled. The problem of determination of the time of divergence of the studied zoarcid-like fish using the concept of “molecular clock” and its calibration according to paleontological and paleogeographic data is discussed.     

12 Phylogeny of the euglenoid loricate genera trachelomonas and strombomonas based on morphological and molecular data

Since the separation of the Trachelomonas subgroup “Saccatae” into a new genus, Strombomonas Deflandre (1930), there has been some question as to its validity. Deflandre's separation was based on morphological characteristics such as the shape of the lorica, lack of a distinctive collar, possession of a tailpiece, lack of ornamentation, and ability to aggregate particles on the lorica. Recent molecular analyses indicated that the loricate taxa were monophyletic, but few species have been sampled. The LSU rDNA from eleven Strombomonas and thirty‐eight Trachelomonas species was sequenced to evaluate the monophyly of the two genera. Bayesian and maximum‐likelihood analyses found one monophyletic clade for each genus. The Trachelomonas clade was weakly supported, but had five strongly supported subclades. Morphological characters, such as lorica development and pellicle strip reduction, also supported separation of the genera. Lorica development in Strombomonas occurred from the anterior of the cell to the posterior, forming a shroud over the protoplast whereas in Trachelomonas, a layer of mucilage was excreted over the entire protoplast, followed by creation of the collar at the anterior end. Taxa from both genera underwent exponential strip reduction at the anterior and posterior poles. In Strombomonas, only one reduction was visible in the anterior pole, while in most Trachelomonas species, two reductions were visible. Likewise, Strombomonas species possessed two whorls of strip reduction in their posterior end compared to a single whorl of strip reduction in Trachelomonas species. The combined morphological and molecular data support the retention of Trachelomonas and Strombomonas as separate genera.     

Phylogenetics and classification of the pantropical fern family Lindsaeaceae

The classification and generic definition in the tropical–subtropical fern family Lindsaeaceae have been uncertain and have so far been based on morphological characters only. We have now studied the evolutionary history of the Lindsaeaceae by simultaneously optimizing 55 morphological characters, two plastid genes (rpoC1 and rps4) and three non‐coding plastid intergenic spacers (trnL‐F, rps4‐trnS and trnH‐psbA). Our data set included all genera associated with Lindsaeaceae, except Xyropteris, and c. 73% of the currently accepted species. The phylogenetic relationships of the lindsaeoid ferns with two enigmatic genera that have recently been included in the Lindsaeaceae, Cystodium and Lonchitis, remain ambiguous. Within the monophyletic lindsaeoids, we found six well‐supported and diagnostic clades that can be recognized as genera: Sphenomeris, Odontosoria, Osmolindsaea, Nesolindsaea, Tapeinidium and Lindsaea. Sphenomeris was shown to be monotypic; most taxa formerly placed in that genus belong to the Odontosoria clade. Ormoloma is embedded within Lindsaea and therefore does not merit recognition as a genus. Tapeinidium is sister to a clade with some species formerly placed in Lindsaea that are morphologically distinct from that genus and are transferred to Osmolindsaea and Nesolindsaea, proposed here as two new genera. We do not maintain the current subgeneric classification of Lindsaea itself, because neither of the two generally accepted subgenera (Lindsaea and Odontoloma) is monophyletic, and most of the sections also appear unnatural. Nesolindsaea shows an ancient biogeographical link between Sri Lanka and the Seychelles and many of the main clades within Lindsaea have geographically disjunct distributions. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 305–359.     

Revisiting the North American freshwater mussel genus Quadrula sensu lato (Bivalvia Unionidae): Phylogeny,taxonomy and species delineation

Freshwater mussels (Bivalvia, Unionidae) have suffered strong declines over the last century. High morphological plasticity of Unionidae causes disturbances in their systematics and taxonomy, hampering conservation efforts. Species that have historically been placed under the North American genus Quadrula have suffered from numerous taxonomic and species delineation problems since its inception. Four genera are presently recognized within Quadrula sensu lato, that is, Cyclonaias, Quadrula, Theliderma and Tritogonia, but their phylogenetic basis remains incompletely tested. In the present study, we reconstructed several two‐marker (mtDNA cytochrome c oxidase subunit I—COI and NADH dehydrogenase subunit 1—ND1) phylogenies with newly collected specimens and all previously available sequences covering most species within this group. We then delineated the species within the group using an integrative approach with the application of molecular statistical methods, morphometric (Fourier Shape) analyses and geographic distribution data. Four clades corresponding to these genera were consistently recovered in all phylogenies. To validate the generic status of these clades, molecular analyses were complemented with morphological, anatomical and ecological data compiled from the literature. Several revisions are here proposed to the current systematics and taxonomy of these genera, including the synonymization of Cyclonaias asperata under Cyclonaias kieneriana; the inclusion of Quadrula apiculata and Quadrula rumphiana under Quadrula quadrula; the placement of Quadrula nobilis under Tritogonia; and finally the separation of the Mobile River basin populations of Theliderma metanevra as a new species, that is, Theliderma johnsoni n. sp. The conservation implications of the proposed changes are then discussed.     

Multilocus phylogeny reveals unexpected diversification patterns in Asian wolf snakes (genus Lycodon)

The diverse group of Asian wolf snakes of the genus Lycodon represents one of many poorly understood radiations of advanced snakes in the superfamily Colubroidea. Outside of three species having previously been represented in higher‐level phylogenetic analyses, nothing is known of the relationships among species in this unique, moderately diverse, group. The genus occurs widely from central to Southeast Asia, and contains both widespread species to forms that are endemic to small islands. One‐third of the diversity is found in the Philippine archipelago. Both morphological similarity and highly variable diagnostic characters have contributed to confusion over species‐level diversity. Additionally, the placement of the genus among genera in the subfamily Colubrinae remains uncertain, although previous studies have supported a close relationship with the genus Dinodon. In this study, we provide the first estimate of phylogenetic relationships within the genus Lycodon using a new multi‐locus data set. We provide statistical tests of monophyly based on biogeographic, morphological and taxonomic hypotheses. With few exceptions, we are able to reject many of these hypotheses, indicating a need for taxonomic revisions and a reconsideration of the group's biogeography. Mapping of color patterns on our preferred phylogenetic tree suggests that banded and blotched types have evolved on multiple occasions in the history of the genus, whereas the solid‐color (and possibly speckled) morphotype color patterns evolved only once. Our results reveal that the colubrid genus Dinodon is nested within Lycodon—a clear finding that necessitates the placing of the former genus in synonymy with the latter.     

Early Jurassic gastropods from England

Abstract: Twenty‐five gastropod taxa are reported from the Early Jurassic (Hettangian to Toarcian) of England. Of these, 14 are identified to species level, and the remaining 11 are treated in open nomenclature. One genus (Lensataphrus) and six species are introduced as new. The new species are Lensataphrus tatei, Lensataphrus tenuis, Tricarilda toddi, Cylindrobullina dorsetensis, Cylindrobullina ventricosa and Consobrinella greeni. The following new combinations are introduced: Cassianopsis hebertana (d’Orbigny, 1852) for Neritopsis hebertana; Cryptaulax abscisum (Terquem and Piette, 1868) for Cerithium abscisum; and Cylindrobullina avena (Terquem, 1855) for Striactaeonina avena. Most of the genera and some of the species are also known from Central Europe (Germany and France). Typical vetigastropod genera that are present in England and Central Europe are Colpomphalus, Costataphrus, Ooliticia, Eucycloscala and Eucycloidea. The caenogastropod genera Levipleura and Cryptaulax are present in both regions, as are the heterobranchs Tricarilda and Cylindrobullina. The heterobranch genus Consobrinella is reported from England for the first time. Gastropods seem to follow the diversity trends of other marine invertebrates during the Early Jurassic. They diversify until the Late Pliensbachian but decrease sharply in number around the Pliensbachian–Toarcian boundary. This may reflect both regional anoxia and a global mass extinction event in the Early Toarcian.