A new identity for the Silurian arthropod Necrogammarus

Restudyof the enigmatic arthropod Necrogammarus salweyi Woodward, hitherto considered to be a crustacean or myriapod, reveals that it is the infracapitulum (fused labrum and palpal coxae) and palp of a large but unspecified pterygoid curypterid

First fossil mesothele spider, from the Carboniferous of France

First fossil mesothele spider, from the Carboniferous of France. Eothele montceauensis n. gen., n. sp., is described from two specimens from the Upper Carboniferous (Stephanian) of Montceau-Ies-Mines,France, as the first fossil and oldest known mesothele spider. In addition to the plesiomorphies characteristic of mesotheles, the holotype of Eothele preserves one mesothele synapomorphy (deep, narrow sternum) and at least one autapomorphy of the genus (biserially dentate chelicerae). The fossil is evidence that both mesotheles and opisthotheles were present in the Carboniferous period

Lower Cretaceous spiders from the Sierra de Montsech, north-east Spain

Four new specimens of spiders (Chelicerata: Araneae), from Lower Cretaceous (Berriasian-Valanginian) lithographic limestones of the Sierra de Montsech, Lérida Province, north-east Spain, are described, as Cretaraneus vilaltae gen. et sp. nov., Macryphantes cowdeni gen. et sp. nov. (two specimens), and Palaeouloborus lacasae gen. et sp. nov. All belong to the infraorder Araneomorphae. Palaeouloborus is the oldest representative of the superfamily Deinopoidea, Cretaraneus is referred to the superfamily Araneoidea, and Macryphantes is the oldest record of the superfamily Araneoidea, family Tetragnathidae (metine-tetragnathine-nephiline group). All three spiders were web weavers; Macryphantes and Palaeouloborus wove orb webs, and may have used a wrap attack to prey on the abundant contemporaneous insect life preserved in the Montsech deposit

Eocene spiders from the Isle of Wight with preserved respiratory structures

A new fossil spider, Vectaraneus yulei gen. et sp. nov., from the Eocene Bembridge Marls Insect Bed of the Isle of Wight, shows internal anatomy, including book lungs and tracheae, preserved by calcium carbonate replacement. The wide, medially positioned, tracheal spiracle and large tracheae which enter the prosoma are adaptations for an amphibious mode of life. The spider is placed in Cybaeidae Simon, 1898, Argyronetinae Menge, 1869, a subfamily which includes the Recent European Water Spider, Argyroneta aquatica (Clerck, 1757). The only previously described Bembridge Marls spider, Eoatypus woodwardii McCook, 1888, is redescribed; it is unrelated to Vectaraneus. The holotype of Argyroneta antiqua Von Heyden (1859) is redescribed; it is not an Argyroneta. Specimens referred to A. antiqua by Bertkau (1878) probably belong in Argyronetinae Menge, 1869, and this subfamily is emended herein

First British Mesozoic spider, from Cretaceous amber of the Isle of Wight, southern England

Cretamygale chasei, a new genus and species of spider, is described from a single specimen preserved in amber of early Barremian age from the Isle of Wight. This is the oldest (and second Cretaceous) amber spider to be described, and the first record of a Mesozoic spider from Britain. It belongs to the group Bipectina of the infraorder Mygalomorphae, and is tentatively referred to the family Nemesiidae. It is the oldest bipectinate, extending the record by around 90 myr, the only known fossil nemesiid, and the second oldest fossil mygalomorph

The development of early terrestrial ecosystems

In this review of terrestrialization by plants and animals in the early Phanerozoic, the classical idea of a major mid-Palaeozoic event is discarded in favour of gradual colonization over a long time period. Four phases of colonization of the land by plants are recognized but their limits are often difficult to define. The first, of microbial mats comprising prokaryotes and later photosynthesizing protists (algae) but with no direct fossil evidence, extends from the Precambrian and may persist in environments unsuitable for colonization by higher plants and animals today. The second, based on microfossils (spores and cuticles) possibly from plants of bryophyte aspect (if not affinity) started in the Ordovician (c. 460 Ma ago) and ended in the Lower Devonian, but was overlapped by the third phase beginning early in the Silurian (c. 430 Ma). This consisted of small plants of axial organization with terminal sporangia probably allied to the tracheophytes. The advent of taller vascular plants of varied organization around the Silurian — Devonian boundary (c. 420–400 Ma) signalled the final pioneering phase — that of major adaptative radiations on land, culminating in the appearance of extant groups, in changes in reproductive strategy and in the development of complex vegetation structure. The animal record is sparser than that of the plants, but suggests an early land fauna in the mid-Palaeozoic which differed from later terrestrial assemblages in lacking herbivores, with the first direct fossil evidence for land animals in the late Silurian

A trigonotarbid arachnid from the early Devonian of Tredomen, Wales

A new trigonotarbid (Arachnida: Trigonotarbida) Arianrhoda bennetti gen. et sp. nov. is described from the Lower Devonian (Lochkovian) of a quarry near Tredomen, Powys, mid Wales, UK. This relatively complete specimen is the first record of a pre-Carboniferous arachnid from Wales, one of only a handful of early Devonian arachnids, and the second oldest trigonotarbid recorded. Based on the rounded prosomal dorsal shield and the relatively narrow, elongate opisthosoma we refer this new fossil to the family Anthracosironidae. A distinct flange-like ornament on the leg 4 tibia in the new fossil is unique among trigonotarbids and is the primary autapomorphy for the new genus

A Triassic spider from Italy

This is the publisher's version, also available electronically from "http://www.app.pan.pl".A new fossil spider from the Triassic (Norian) Dolomia di Forni Formation of Friuli, Italy, is described as Friularachne rigoi gen. et sp. nov. This find brings the number of known Triassic spider species to four. The specimen is an adult male, and consideration of various features, including enlarged, porrect chelicerae, subequal leg length, and presence of a dorsal scutum, point to its identity as a possible member of the mygalomorph superfamily Atypoidea. If correct, this would extend the geological record of the superfamily some 98–115 Ma from the late Early Cretaceous (?Albian, c. 100–112 Ma) to the late middle–early late Norian (c. 210–215 Ma)

A new Silurian xiphosuran from Podolia, Ukraine, USSR

A single incomplete specimen of a xiphosuran, Pasternakevia podolica gen. et sp. nov., from the Ludlow Series of Podolia, Ukraine, USSR, is described. It has a smooth, spatulate carapace and rounded genal cornua. The opisthosoma bears nine free tergites (second to tenth); the first tergite is reduced and hidden beneath the carapace. The tergites have a broad axial region and small pleurae; the second tergite is hypertrophic. Telson and appendages are not preserved. P. podolica resembles Pseudoniscus Nieszkowski, 1859 and Cyamocephalus Currie, 1927; it is thus placed in the infraorder Pseudoniscina Eldredge, 1974, but certain characters are shared with the synziphosurines. It comes from the lagoonal deposits of the upper part of the Ustye Suite (Bagovytsa Horizon) where it occurred together with Baltoeurypterus tetragonophthalmus (Fischer, 1839)

Babes in the wood – a unique window into sea scorpion ontogeny

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author’s publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.BACKGROUND: Few studies on eurypterids have taken into account morphological changes that occur throughout postembryonic development. Here two species of eurypterid are described from the Pragian Beartooth Butte Formation of Cottonwood Canyon in Wyoming and included in a phylogenetic analysis. Both species comprise individuals from a number of instars, and this allows for changes that occur throughout their ontogeny to be documented, and how ontogenetically variable characters can influence phylogenetic analysis to be tested. RESULTS: The two species of eurypterid are described as Jaekelopterus howelli (Kjellesvig-Waering and Størmer, 1952) and Strobilopterus proteus sp. nov. Phylogenetic analysis places them within the Pterygotidae and Strobilopteridae respectively, both families within the Eurypterina. Jaekelopterus howelli shows positive allometry of the cheliceral denticles throughout ontogeny, while a number of characteristics including prosomal appendage length, carapace shape, lateral eye position, and relative breadth all vary during the growth of Strobilopterus proteus. CONCLUSIONS: The ontogeny of Strobilopterus proteus shares much in common with that of modern xiphosurans, however certain characteristics including apparent true direct development suggest a closer affinity to arachnids. The ontogenetic development of the genital appendage also supports the hypothesis that the structure is homologous to the endopods of the trunk limbs of other arthropods. Including earlier instars in the phylogenetic analysis is shown to destabilise the retrieved topology. Therefore, coding juveniles as individual taxa in an analysis is shown to be actively detrimental and alternative ways of coding ontogenetic data into phylogenetic analyses should be explored