A new species of Hemichela Stock, 1954 from the South China Sea (Arthropoda,Pycnogonida, Ammotheidae)

A new species of pycnogonid collected by the Chinese research vessel, R/V HY IV, during deep sea cruises to the South China Sea in 2013, is described. The new species, Hemichela nanhaiensis, obtained from more than 1300 m depth, is distinguished from the other two species in the genus by the characters of the chela dactylus with 12 denticulations on the inner margin and by the presence of taller tubercles on the lateral processes.     

Synopsis of a new collection of sea spiders (Arthropoda: Pycnogonida) from the Ross Sea,Antarctica

The biodiversity research expedition TAN0204 with RS Tangaroa to the Ross Sea in 2004 yielded a new collection of 2,687 specimens of pycnogonids. As much as 25 different species encompassing 14 genera and eight families were identified and their records are discussed herein. The collection is archived in the Marine Invertebrate Collection of the New Zealand National Institute of Water and Atmospheric Research (NIWA). The majority (69%) of specimens are from the Nymphon australe group (Nymphonidae), although species richness and abundance varied among the stations sampled. The collection includes several specimens from polymerous taxa; Pentanymphon antarcticum (Nymphonidae), Decolopoda australis (Colossendeidae) and Pentapycnon bouvieri (Pycnogonidae). All species were classified based on morphological characters, and DNA sequences (from the 18S, 12S, 16S and COI regions) for 21 of the representative morphotypes are given. The DNA sequences confirmed the species-level distinctiveness of these morphotypes. No species new to science were identified, although further detailed morphometric and/or molecular analyses may reveal cryptic or sibling species, especially in species such as the highly abundant Nymphon australe group. An erratum to this article can be found at     

Anatomy and lifestyle of Kunmingella (Arthropoda, Bradoriida) from the Chengjiang fossil Lagerstätte (lower Cambrian; Southwest China)

An updated reconstruction of the body plan, functional anatomy and life attitude of the bradoriid arthropod Kunmingella is proposed, based on new fossil specimens with preserved soft parts found in the lower Cambrian of Chengjiang and Haikou (Yunnan, SW China) and on previous evidence. The animal has a single pair of short antennae pointing towards the front (a setal pattern indicates a possible sensory function). The following set of seven appendages (each composed of a 5-segmented endopod and a leaf-like exopod fringed with setae) is poorly differentiated, except the first three pairs (with possible rake-like endopodial outgrowths, smaller exopods) and the last pair of appendages (endopod with longer and more slender podomeres). The endopods are interpreted as walking legs with a possible role in handling food particles (marginal outgrowth with setae). The leaf-like exopods may have had a respiratory function. The trunk end is short, pointed, flanked with furcal-like rami and projects beyond the posterior margin of the carapace. The attachment of the body to the exoskeleton is probably cephalic and apparently lacks any well-developed adductor muscle system. The inferred life attitude of Kunmingella (e.g. crawling on the surface of the sediment) was that of a dorsoventrally flattened arthropod capped by a folded dorsal shield (ventral gape at least 120°), thus resembling the living ostracode Manawa. The animal was also probably able to close its carapace as a response to environmental stress or to survive unfavourable conditions (e.g. buried in sediment). The anterior lobes of the valves are likely to have accommodated visual organs (possibly lensless receptors perceiving ambient light through the translucent head shield). Preserved eggs or embryos suggest a possible ventral brood care. The presence of Kunmingella in coprolites and its numerical abundance in Chengjiang sediment indicate that bradoriids constituted an important source of food for larger predators. Kunmingella differs markedly from the representatives of the crown group Crustacea (extant and Cambrian taxa) and from the stem group derivatives of Crustacea (exemplified by phosphatocopids and some ‘Orsten’ taxa) in showing no major sign of limb specialization (e.g. related to feeding strategies). Although it resembles other Chengjiang euarthropods in important aspects of its body plan (e.g. uniramous antennae, endopod/exopod configuration), Kunmingella possesses several features (e.g. antennal morphology, post-antennular appendages with 5-segmented endopods) which support the view that bradoriids may be very early derivatives of the stem line Crustacea.     

Morphological phylogenetics of the sea spiders (Arthropoda: Pycnogonida)

Pycnogonids or sea spiders are a group of marine arthropods whose relations to the chelicerates have been an issue of controversy. Higher-level phylogenetic relationships among the lineages of sea spiders are investigated using 36 morphological characters from 37 species from all extant families and a Devonian pycnogonid fossil. This is one of the first attempts to analyze the higher-level relationships of the Pycnogonida using cladistic techniques. Character homoplasy (implied weights) is taken into account to construct a polytomous, most-parsimonious tree in which two major clades within Pycnogonida are obtained. Clade A includes Ammotheidae paraphyletic with Colossendeidae, Austrodecidae and Rhynchothoracidae, and clade B is formed by Nymphonidae, Callipallenidae (apparently paraphyletic), Pycnogonidae and Phoxichilidiidae. The analysis of equally weighted data is presented and helps to identify those characters less consistent. The reduction of the chelifores, palps and ovigers — shown independently within each of the clades as parallel evolution events — challenges the assumption of a gradual mode of reduction within the group, according to analysis of unordered vs ordered characters. Most of the phylogenetic affinities proposed here are compatible with traditional classifications. However, traditional taxonomic characters need to be complemented by sets of anatomical, molecular and developmental data, among others, to produce more robust phylogenetic hypotheses on the higher- and lower-level relationships of the sea spiders.     

A new species of Hedgpethia (Arthropoda, Pycnogonida, Colossendeidae) from southwestern Japan

We describe Hedgpethia spinosasp. n. based on a single male specimen obtained from 197-207 m depth, south of Yaku Island, Kagoshima Prefecture, Japan. Among 15 previously known congeners, the new species resembles Hedgpethia bicornis (Losina-Losinsky & Turpaeva, 1958), Hedgpethia chitinosa (Hilton, 1943), and probably Hedgpethia brevitarsis (Losina-Losinsky & Turpaeva, 1958), in having a mid-dorsal tubercle on the posterior rim on each trunk segment. The new species, however, is distinguishable from those by a pair of horns on the anterior margin of the cephalic segment, spines on the first coxae, and denticulate spines on the strigilis. The new species represents the fifth member of the genus so far known from Japanese waters, in addition to Hedgpethia brevitarsis (Losina-Losinsky & Turpaeva, 1958), Hedgpethia chitinosa (Hilton, 1943), Hedgpethia dofleini (Loman, 1911), and Hedgpethia elongata Takahashi, Dick & Mawatari, 2007.     

Ontogeny of the Upper Cambrian (Furongian) Olenid trilobite Protopeltura aciculate (Angelin, 1854) from Skåne and Västergötland,Sweden

Abstract: The ontogeny of the trilobite Protopeltura aciculata (Angelin, 1854) is described on the basis of material from the upper Cambrian (Furongian) of Andrarum (Skåne) and Hjelmsäter (Västergötland), Sweden. P. aciculata is present in the Parabolina brevispina and Parabolina spinulosa zones. Protopeltura aciculata is represented by all stages of growth, from early protaspides to holaspides, although most of the specimens are disarticulated and precise degrees are unknown. The cranidia have therefore been allocated to five morphological groups. Cuticular sculpture of the cranidia changes throughout ontogeny. Large tubercles are present in earlier stages, disappear gradually in middle meraspid stages and are replaced with a very faint granulation. The transitory pygidium, relatively large and shield‐shaped with upwardly and backwardly directed marginal spines in early meraspides, later becomes very small, triangular‐shaped and lacking spines as a late meraspid and holaspid. The development of hypostomes and librigenae is also described. Protopeltura aciculata shows major intraspecific variations throughout development, especially regarding the pygidium where variation is much less constrained than in many other olenids. This high developmental plasticity may be a survival strategy for a trilobite living in a stressed environment. Protopeltura inhabited a dysoxic environment, possibly unusually prone to localised spreading of anoxic or toxic water. Some morphs may have been less vulnerable than others to such stresses, surviving by chance and thus enabling the species to continue.     

A myriapod-like arthropod from the Upper Cambrian of East Siberia

Although the fossil record of biramous arthropods commences in the Lower Cambrian, unequivocal uniramous arthropods do not appear until the Upper Silurian, in association with terrestrial biotas. Here we report an Upper Cambrian marine arthropod from East Siberia that possesses some significant myriapodan features. The new arthropod,Xanthomyria spinosa n. gen., n. sp., closely resembles examples of archipolypodans from the Late Palaeozoic. If this resemblance genuinely represents myriapod affinities, this would be the first convincing myriapod from the Cambrian. Suggestions of an early branching point of the myriapods from other arthropods would be consistent with this. Conversely, an as yet poorly known clade of multi-segmented arthropods may exist in the Cambrian, with no close affinities to the myriapods.      

The deep-water pycnogonids (Arthropoda: Pycnogonida) of the northeastern Atlantic Ocean

Over 2000 specimens of pycnogonid from deep-sea collections made in the northeastern Atlantic Ocean by IOS and SMBA between 1971 and 1994 have been analysed. Thirty-five species were identified, two being new to science, viz Nymphon akanthochoeros and an unnamed Anoplodactylus species. The deep-sea Pycnogonida of the northeastern Atlantic are reviewed using these data and records from the literature. Keys are presented for the six families represented by more than one species. The pycnogonid fauna of this area is characterized particularly by Paranymphon spinosum and Colossendeis clavata , with other dominant species including Colossendeis species, notably C. macenima , and Nymphon laterospinum, Anoplodactylus typhlops and A. arnaudae. Of the 54 species recorded below 200 m in the northeastern Atlantic, available evidence suggests that nine are 'endemic'. Relative distributions of the other species are discussed. A distinct change in the pycnogonid fauna with depth was found at around 1400 m. There is latitudinal separation of species groupings, shown most conspicuously by the shallower water species.     

A scanning electron microscopy study of the embryonic development of Pycnogonum litorale (Arthropoda,Pycnogonida)

The phylogenetic position of the enigmatic Pycnogonida (sea spiders) is still controversial. This is in part due to a lack of detailed data about the morphology and ontogenesis of this, in many aspects, aberrant group. In particular, studies on the embryonic development of pycnogonids are rare and in part contradictory. Here, we present the first embryological study of a pycnogonid species using scanning electron microscopy (SEM). We describe the late embryogenesis of Pycnogonum litorale from the first visible appendage anlagen to the hatchling in 11 embryonic stages. The three pairs of appendage anlagen gain in length by growth, as well as by extension of furrows into the embryo. The opening of the stomodaeum is located far in front of the anlagen of the chelifores and has a Y‐shaped lumen from the onset. During further embryogenesis, the position of the mouth shifts ventrally, until it is located between the chelifores. The proboscis anlage grows out as a circumoral wall‐like structure, which is initially more pronounced ventrally. Hypotheses about the evolution of the proboscis by fusion of originally separated components are critically discussed, because the proboscis anlage of P. litorale shows no indications of a composite nature. In particular, a participation of post‐cheliforal elements in proboscis formation is rejected by our data. Further, no preoral structure and no stage in proboscis formation was found, which could plausibly be homologized with the labrum of othereuarthropods. Thus, our study supports the assumption of a complete lack of a labrum in Pycnogonida. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.     

Structure, ontogeny, and moulting of the olenid trilobite Ctenopyge (Eoctenopyge) angusta Westergård, 1922 from the upper Cambrian of Västergötland, Sweden

The genus Ctenopyge is known mainly from disarticulated sclerites and from rare complete specimens flattened in shales. Hitherto, very few specimens have been found preserved intact and in three dimensions. In a recently discovered fauna, however, in the Peltura minor Subzone in Västergötland, central Sweden, there occur several species of Ctenopyge , of which many are complete and superbly preserved; moreover they occur at all stages of growth. Of these the abundant Ctenopyge ( Eoctenopyge ) angusta Westergård, 1922 is described and reconstructed here as an adult, and the entire ontogeny is documented for all post–protaspid growth stages. Many characters typical of the adult, such as the long genal spines and the caudal spine, develop very early in ontogeny, and the relative dimensions of the cranidium do not greatly change during growth. Macropleural spines, however, develop later. The transitory pygidium, relatively large and shield–shaped in the early meraspid, later becomes very small as the ten thoracic segments are liberated; a median spine develops on the last thoracic segment only at the holaspid stage. Instar groupings can be clearly distinguished for the early stages. Recurrent associations of sclerites are interpreted as moulting configurations. As reconstructed, the genal spines are horizontal and parallel with the extended thorax; an adaptation which presumably allowed the trilobite to rest on the sea floor.     

Phylogenetic affinities and taphonomy of Brooksella from the Cambrian of Georgia and Alabama, USA

Siliceous “star cobbles”, referred to the enigmatic genus Brooksella, are abundant in the Conasauga Formation of the Coosa River Valley of Alabama and Georgia, USA. Explaining the phylogenetic affinities and taphonomic history of Brooksella has been difficult and contentious. Brooksella has, at times, been referred to: 1, the cnidarian order Scyphomedusae; 2, the cnidarian class Protomedusae (order Brooksellida); 3, as algae; 4, as a trace fossil; and 5, as a feature of inorganic origin.Macroscopic, microscopic, and computer-assisted tomographic analysis of Brooksella from the Conasauga Formation suggests that the “star cobbles” represent exceptionally preserved body fossils of simple construction. Morphology of star cobbles is most consistent with a siliceous (hexactinellid) sponge interpretation. Specimens show wide morphologic variation, including gradational patterns, suggesting that a single species name (Brooksella alternata) should be used to embrace all forms described from the Coosa Valley. B. alternata includes specimens having a variable number of radially disposed lobes divided by radial grooves, and often a central opening inferred to be an osculum on one side. Lobes in many specimens terminate in small openings. Small craterlike structures, inferred to be ostia, are present on the external surface. Radial internal cavities occupy the lobes. Specimens from the Conasauga Formation have siliceous spicules preserved surficially and internally.The three-dimensional nature of most “star cobbles” suggests rapid fossil diagenesis, perhaps mediated by the activities of microbial consortia that quickly formed biofilms around the dead hosts.     

Variation in Nymphon brevirostre (Hodge), and the status of N. rubrum (Hodge) (Arthropoda: Pycnogonida)

A series of morphometric analyses conducted on specimens of Nymphon brevirostre Hodge and Nymphon rubrum Hodge from British waters has shown that the characteristics variously used in the past to distinguish these two species are invalid. In this material these characteristics range from the extreme of the typical N. brevirostre form to that of the typical N. rubrum form, with most of the specimens exhibiting an intermediate morphology. Multivariate analyses showed no significant splitting of the material into two groups which might correlate to Hodge's two species. Protonymphon larvae from males of both typical extreme forms were morphologically identical. It is concluded that N. rubrum is a junior synonym of N. brevirostre, a variable species whose morphology tends towards the rubrum form as the animal grows.     

Variation in Nymphon brevirostre (Hodge), and the status of N. rubrum (Hodge) (Arthropoda: Pycnogonida)

A series of morphometric analyses conducted on specimens of Nymphon brevirostre Hodge and Nymphon rubrum Hodge from British waters has shown that the characteristics variously used in the past to distinguish these two species are invalid. In this material these characteristics range from the extreme of the typical N. brevirostre form to that of the typical N. rubrum form, with most of the specimens exhibiting an intermediate morphology. Multivariate analyses showed no significant splitting of the material into two groups which might correlate to Hodge's two species. Protonymphon larvae from males of both typical extreme forms were morphologically identical. It is concluded that N. rubrum is a junior synonym of N. brevirostre , a variable species whose morphology tends towards the rubrum form as the animal grows.     

Lower Cambrian (Botomian) polycystine Radiolaria from the Altai Mountains (southern Siberia, Russia)

Relatively well-preserved polycystine Radiolaria are here described from Lower Cambrian (Botomian) strata of the Shashkunar Formation, Altai Mountains in southern Siberia (Russia). These radiolarians display a test formed of a disorderly and three-dimensionally interwoven meshwork of numerous straight and curved bars branching from a five-rayed point-centered spicule located within the inner shell surface. The shell structure allows their assignment to the family Archeoentactiniidae, thus extending the known age range of the family down to the Lower Cambrian. The Botomian age is based essentially on trilobites (Parapagetia-Serrodiscus zone), but also on archaeocyathids identified in earlier publications. The study of the radiolarian-bearing sedimentary sequence confirms the presence of polycystine radiolaria in the external platform environments of Lower Cambrian ecosystems.     

New occurrence of the family Hipponicharionidae (Bradoriida, Arthropoda), in the lower and middle Cambrian of the Cadenas Ibéricas, Spain

The bradoriids Hipponicharion aff. hispanicum and Wimanicharion aff. matthewi are reported from the lower and middle Cambrian strata of the Cadenas Ibéricas, Spain. The genus Hipponicharion seems to be restricted to the Acadobaltic Province. Wimanicharion has been recorded from Sweden and Canada (Nova Scotia). The new discovery of Wimanicharion in Spain indicates its similar palaeobiogeographical distribution to Hipponicharion.     

Spiders in Upper Cretaceous Amber from New Jersey (Arthropoda: Araneae)

The oldest described fossils of the extant spider families Segestriidae, Oonopidae, Oecobiidae, Dictynidae and Linyphiidae, previously known from the Tertiary, are presented from Upper Cretaceous amber of New Jersey. The third and oldest known specimen of the fossil spider family Lagonomegopidae is also described and provides further palaeontological evidence of a common Laurasian fauna. The extant genera Segestria and Oecobius are taken back a further 52 and 69–74 myr respectively in the fossil record. These fossils predict the presence of the Caponiidae, Tetrablemmidae, Orsolobidae, Dysderidae, Hersiliidae, Eresidae, Pimoidae, Scytodoidea s.l. , cyatholipoids, theridioids and symphytognathoids in the Cretaceous. They also extend the known geological range of extant spider families through and beyond the end–Cretaceous extinction. This event, which affected numerous marine and some terrestrial organisms, probably had little effect on the Araneae.     

Phylogeny of the sea spiders (Arthropoda, Pycnogonida) based on direct optimization of six loci and morphology

Higher‐level phylogenetics of Pycnogonida has been discussed for many decades but scarcely studied from a cladistic perspective. Traditional taxonomic classifications are yet to be tested and affinities among families and genera are not well understood. Pycnogonida includes more than 1300 species described, but no systematic revisions at any level are available. Previous attempts to propose a phylogeny of the sea spiders were limited in characters and taxon sampling, therefore not allowing a robust test of relationships among lineages. Herein, we present the first comprehensive phylogenetic analysis of the Pycnogonida based on a total evidence approach and Direct Optimization. Sixty‐three pycnogonid species representing all families including fossil taxa were included. For most of the extant taxa more than 6 kb of nuclear and mitochondrial DNA and 78 morphological characters were scored. The most parsimonious hypotheses obtained in equally weighted total evidence analyses show the two most diverse families Ammotheidae and Callipallenidae to be non‐monophyletic. Austrodecidae + Colossendeidae + Pycnogonidae are in the basal most clade, these are morphologically diverse groups of species mostly found in cold waters. The raising of the family Pallenopsidae is supported, while Eurycyde and Ascorhynchus are definitely separated from Ammotheidae. The four fossil taxa are grouped within living Pycnogonida, instead of being an early derived clade. This phylogeny represents a solid framework to work towards the understanding of pycnogonid systematics, providing a data set and a testable hypothesis that indicate those clades that need severe testing, especially some of the deep nodes of the pycnogonid tree and the relationships of ammotheid and callipallenid forms. The inclusion of more rare taxa and additional sources of evidence are necessary for a phylogenetic classification of the Pycnogonida. © The Willi Hennig Society 2006.     

Three species of Pagodia (Corynexochida,Trilobita) from the Furongian (Cambrian) of northern Anhui,China and their intraspecific variation

More than one thousand cranidia, librigenae, and pygidia of the trilobite Pagodia were collected from the Cambrian (upper Jiangshanian through Stage 10) at Fenghuangshan in northern Anhui, China. They were identified as Pagodia lotos Walcott, 1905, Pagodia depressa (Walcott, 1905), and Pagodia bia Walcott, 1905. Based on one rare nearly complete exoskeleton of P. depressa and comparisons among the three species of Pagodia, the redefinition for those species is attempted as follows. Pagodia lotos: Glabella rectangular, slightly convergent anteriorly; anterior border ridge-like, anterior border furrow deep; pygidium semicircular, axis tapered rearward, with 4 axial rings and a terminal piece. P. depressa: Cranidium subquadrate, highly convex; glabella cylindrical, convergent anteriorly; pygidium semicircular. P. bia: Glabella rectangular, constricted in the midlength; fixigena wide (tr.); anterior border very narrow (sag.) and ridge-like; pygidium semicircular with wide borders; pygidial axis ended closer to the pygidial border furrow. We also discuss their intraspecific variations, commonly seen on the exfoliated specimens: palpebral ridge evident or obliterated, the length (sag.) of anterior area variable, the decoration of exoskeleton surface (with granules variable in size, convex or pitted).     

寒武系杷榔组Redlichia (Peteroredlichia) chinensis（Walcott，1905）个体发育研究

贵州东部寒武纪的杷榔组发育,化石丰富,含有杷榔动物群;其中掘头虫类、莱德利基虫类三叶虫保存好,序列完整,提供了研究这些类群属种个体发育的重要材料。本文据杷榔组Redlichia (Pteroredlichia) chinensis（Walcott,1905）的300多块标本的分析数据,详细讨论和重点研究了其从幼虫期、分节期至成虫期个体发育特征,分析各个阶段的形态变化及个体发育演化趋势。丰富了R.(Pteroredlichia) chinensis个体发育的资料,对莱德利基虫属种厘定起到积极的作用,提供了属种分类对比的重要证据。