Morphology and phylogenetic interpretation of a new Cambrian edrioasteroid (Echinodermata) from Spain

Abstract: The edrioasteroid, Aragocystites belli gen. nov. sp. nov. from the middle Cambrian Murero Formation of Spain, is described based on a small number of very well‐preserved specimens. Important anatomical characteristics include star‐shaped and pseudoclavate theca, rare or absent epispires, well‐developed interradially positioned oral plates and several unorganized cover plates associated with each widely exposed flooring plate. A phylogenetic analysis including several Cambro–Ordovician species shows it is more derived than Stromatocystites and Totiglobus but is a sister group to a clade comprising Cambraster and Edriodiscus. Ontogenetic observations based on juveniles of 5 mm in diameter suggest that this species changed thecal shape markedly during growth. A. belli gen. nov. sp. nov. probably lived in quiet environments where it attached directly to the sea floor on stabilized substrates.     

The oldest cinctan carpoid (stem‐group Echinodermata), and the evolution of the water vascular system

A new cinctan ( Protocinctus mansillaensis gen. et sp. nov. ), from the early Middle Cambrian of the Iberian Chains (north‐east Spain), is described with the aid of X‐ray microtomography and three‐dimensional computer models. Investigation in this manner was possible because of the unusual condition of the fossils, which are preserved as recrystallized calcite. Protocinctus gen nov. possesses an elongate body with a single left anterior feeding groove and an open posterior marginal frame (in ventral view): this combination of characters is unique amongst cinctans. Through the study of original specimens and ‘virtual fossils’ it was possible to reconstruct the palaeobiology of Protocinctus gen. nov. : cinctans are interpreted as pharyngeal basket feeders with a U‐shaped gut, using their posterior appendage to aid stability on the sediment surface. Cinctans are critical to understanding the evolutionary history of the echinoderm stem group, as they illustrate the transition from a paired water vascular system (basal) to one constructed from just the left hydrocoel (derived). The former condition is also observed in another group of stem‐group echinoderms, the ctenocystoids, and is hypothesized for the latest common ancestor of the echinoderms and hemichordates.     

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.     

Reinterpretation of Dracochela deprehendor (Arachnida: Pseudoscorpiones) as a stem‐group pseudoscorpion

Abstract: The middle Devonian (Givetian–Eifelian) pseudoscorpion Dracochela deprehendor Schawaller, Shear and Bonamo is redescribed from the type material and an additional palpal fragment. Dracochela differs from extant pseudoscorpions in having numerous spinules on the leg tarsi, the femur at least as long as the patella on the posterior legs, the stem of the arolia thick, most blades of the serrulae only weakly fused and in lacking a spinneret on the chelicera. The blades of the cheliceral rallum are shown to have been arranged in two rows, as in most Heterosphyronida. The cheliceral serrulae are compared with analogous structures in other arachnids (Notostigmata, Opiliones, Palpigradi, Schizomida and Scorpiones), and it is concluded that the panctenal state (all lamellae attached to finger) is plesiomorphic relative to the hemictenal state (apical lamellae raised), which has evolved independently in Heterosphyronida and Neobisioidea. The trichobothriotaxy of the chela of Dracochela is shown to be similar to that of the extant family Pseudotyrannochthoniidae. The growth of the chelal fingers followed the same pattern as that seen in modern pseudoscorpions, with most of the increase in length occurring at the base of the fingers. The family Dracochelidae Schawaller, Shear and Bonamo is treated as a plesion and assigned to the stem‐group of Pseudoscorpiones. The ordinal name Chelonethi Thorell is restricted to crown‐group pseudoscorpions, and the superordinal name Pseudoscorpiones Latreille is adopted for the total‐group (i.e. stem‐group plus Chelonethi).     

A new Upper Carboniferous stem‐orthopteran (Insecta) from Ningxia (China)

Abstract During the Upper Carboniferous, orthopteran insects (grasshoppers, katydids, and crickets) were represented by numerous species distantly related to crown‐orthopterans, such as lobeattid and cnemidolestodean insects. The panorthopterans, including total‐orthopterans and their closest relatives, are represented by comparatively rarer species in localities of this period. Here we describe Heterologus duyiwuer sp. nov., an infrequent panorthopteran from the Late Carboniferous locality of Xiaheyan Village (Zhongwei City, Ningxia Hui Autonomous Region, China). The only available specimen is composed of an isolated forewing exhibiting a combination of character states previously unknown, in particular the lack of posterior radius (RP) / anterior Media (MA) connection, late branchings of the media (M) and anterior cubitus (CuA), and a branched posterior branch of the posterior cubitus (CuPb). Based on its unusual branching pattern, the composite stem resulting from the fusion of CuA and CuPaα (second anterior branch of CuP) is assumed to be composed of a branched CuA and a simple CuPaα.     

Testing for a decline in diversity prior to extinction: Languedocian (latest mid‐Cambrian) distribution of cinctans (Echinodermata) in the Iberian Chains,NE Spain

Abstract: The middle Cambrian strata of the Iberian Chains (north‐eastern Spain) and the Montagne Noire (southern France) record an adaptative radiation of cinctans and trilobites, which spanned the Leonian–early Languedocian interval. A diachronous diversity peak was reached by both benthic groups when favourable palaeoenvironmental conditions (clayey vs. silty substrates) were established. The acme in diversity was followed by a gradual decline and a barren interval associated with the onset of the mid‐Languedocian regression, well constrained throughout the western Mediterranean region. For trilobites, the aftermath of the regression is characterized by a late‐Languedocian major faunal turnover of families, followed by a renewed Furongian–early Tremadocian radiation related to the stepwise immigration of trilobite invaders from northern and eastern Gondwana, under persistent transgressive conditions. In contrast, the cinctans reappeared only patchily in late‐Languedocian monospecific coquinas and finally disappeared before the Furongian. Thus, the late Languedocian is a crucial interval in which to analyse the decline in diversity and final extinction of cinctans in the aftermath of the mid‐Languedocian regression.     

Pædomorphic patterns of the Cambrian genus Alueva (Trilobita, Ellipsocephalidae) from the Iberian Chains (NE Spain)

Three hundred protaspid and meraspid specimens of the trilobite species Alueva undulata Sdzuy, 1961 from the uppermost Bilbilian limestones of the Valdemiedes Formation (Iberian Chains, NE Spain) have been released by the action of acid. A pædomorphocline is proposed embracing the different species of Alueva, based on the comparison of the ontogenic patterns of the species Alueva undulata Sdzuy, 1961, and the adult morphologies of Alueva moratrix (Sdzuy, 1958). This analysis suggests that the species Alueva? hastata (Sdzuy, 1958) is not related to the pædomorphocline, and provides an approach for evaluating the phylogenetic relationships between the species A. undulata and A. moratrix, which occur across the Lower-Middle Cambrian transition in the Iberian Chains, directly linked with the Valdemiedes event.     

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.     

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。     

A new Alokistocaridae Resser, 1939 (Trilobita) from the middle Cambrian of Spain

A new trilobite species, Schopfaspis? graciai, from the middle Cambrian of Spain is the first member of Alokistocaridae reported from west Gondwana. A cladistic analysis of this trilobite and other Gondwanan trilobites of possible alokistocarid affinities (Schopfaspis granulosa, Chelidonocephalus anatolicus, Derikaspis toluni, Kounamkites multiformis) suggests that this family can be divided into two subfamilies: Alokistocarinae and Altiocculinae. Schopfaspis? graciai nov. sp. and Schopfaspis granulosa are assigned to the subfamily Altiocculinae laying in a more basal position than Altiocculus species. The cladistic analysis also demonstrates a possible relationship of Chelidonocephalus anatolicus and Derikaspis toluni with Alokistocaridae. Enrolment is analysed in this new trilobite describing novelties in the ventral surface of the cephalon which allowed interlocking of the trunk and cephalon in a discoidal enrolment-type.     

The ontogeny of the cypridid ostracod Eucypris virens (Jurine, 1820) (Crustacea,Ostracoda)

The chaetotaxy (shape, structure and distribution of setae) of appendages and valve allometry during the post embryonic ontogeny of the cyprididine ostracod Eucypris virens are described. It is shown that the basic ontogenetic development of E. virens is very similar to that of other species of the family Cyprididae. During ontogeny, the chaetotaxy shows continual development on all podomeres of the limbs with the exception of the last podomere on the antennulae. The long setae on the exopodite and protopodite of the antennae have a natatory function until the actual natatory setae develop in later instars. Aesthetascs (presumed chemoreceptors) ya and y3 are the first to develop and may have an important function in the first instars. Cyprididae require a pediform limb in the posterior of the body presumably to help them to attach to substrates and this is reflected by the pediform nature of one limb at all times throughout all instars. This study has also shown that the fifth limb is most probably of thoracic origin and hence ostracods have only one pair of maxillae.     

Plywood‐like shell microstructures in hyoliths from the middle Cambrian (Drumian) Gowers Formation,Georgina Basin,Australia

Hyoliths are a group of Palaeozoic fossils with calcareous shells whose affinities remain controversial. As their shells were originally aragonitic, their fossils are usually coarsely recrystallized, and few data on their microstructure are available. We report hyoliths from the middle Cambrian (Drumian, Floran) Gowers Formation of the eastern Georgina Basin, Queensland. These are preserved as phosphatic internal moulds, often with the inner layers of the shell also partly replaced by phosphate. Microstructural details preserved by this early diagenetic phosphatization show that these hyolith conchs were originally composed of fibrous crystallites, c. 0.5 μm wide, parallel to one another and to the inner surface of the shell. In several species, the fibres are arranged in a plywood‐like structure composed of multiple lamellae with a different fibre orientation in each lamella: often they are transversely oriented (relative to the long axis of the conch) in the inner part of the wall and longitudinally oriented in the outer part. Opercula also show a microstructure of parallel fibres. The lamello‐fibrillar microstructure we report from hyoliths is reminiscent of microstructures of many Cambrian molluscs; that this microstructure is found in both conchs and opercula suggests that these structures are serial homologues of one another, and in this respect they resemble brachiopod valves. As with many other biological plywoods, the hyolith shell probably records self‐organization in a liquid‐crystal‐like organic matrix. This provided a straightforward way to construct a material that could resist stresses from different directions, offering an effective defence against predators.     

Egarapithecus narcisoi, a new genus of Pliopithecidae (primates, catarrhini) from the Late Miocene of Spain

Pliopithecid remains from the Spanish locality of Torrent de Febulines (Late Vallesian, MN 10), consisting of right and left mandibular fragments with partial tooth rows and an isolated P(3) probably belonging to the same individual, are described and assigned to Egarapithecus narcisoi gen. et sp. nov. (Pliopithecidae, Crouzeliinae). This is a highly derived species dated at around 9 Ma (Ma = 10(6) years), representing the latest appearance of the family in the European continent. Morphologically it is the most distant member from the inferred primitive pliopithecid morphotype, displaying many autapomorphies that notably accentuate those of the remaining Crouzeliinae. A cladistic analysis based on lower cheek teeth, performed in order to tentatively assess the phylogenetic relationships of Egarapithecus within the Crouzeliinae, indicates that several equally parsimonious cladograms are possible in the light of current evidence. This is due to uncertainties regarding the position of Plesiopliopithecus and Crouzelia (here considered distinct genera), as a result of missing characters and the significant degree of homoplasy apparently involved in crouzeliine dental evolution. Whether Egarapithecus is more closely related to Crouzelia or to Anapithecus (the latter hypothesis tentatively favored here) cannot be definitively resolved with the currently available material and deserves further investigation. It is clear, however, that Egarapithecus is one of the more derived and specialized members of the Pliopithecidae.     

The genus Teliocrinus (Crinoidea,Echinodermata): a key taxon among pentacrinid stalked crinoids

The main characters of the stalked crinoids of the family Pentacrinitidae attributed to the genus Teliocrinus are re‐evaluated from a quantitative study of phenotype variation, new observations on arm and stalk articulations, and observation of ontogenetic trends. All of the specimens collected in the northern Indian Ocean belong to the same species, i.e. Teliocrinus springeri (Clark, 1909). However, two phenotypes living at different depths remain valid as subspecies: Teliocrinus springeri springeri (Clark, 1909) and Teliocrinus springeri liliaceus (Clark, 1909). Teliocrinus shares several ontogenetic trends with Endoxocrinus, especially in nonfunctional brachial articulations and stalk symplexies. Its assignment to the Diplocrininae is confirmed. A discussion of its affinities with pentacrinid fossil genera in which the crown is well preserved suggests that Diplocrininae could have first appeared during the Lower Cretaceous. A shortening of brachitaxes and a paedomorphic trend of stalk symplexies are the main other evolutionary traits. Nonfunctional articulations are frequently found at the paedomorphic pole of the heterochronic gradient, without clear derived characters. Classification of pentacrinids mainly based on such symplesiomorphy or paedomorphic characters must be definitively abandoned. However, in post‐Palaeozoic stalked crinoids the scarcity of well‐preserved fossils, the high frequency of paedomorphy, and convergent adaptive characters makes phylogenetic reconstruction only based on morphological characters very difficult and speculative. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 22–39.     

Post‐metamorphic allometry in the earliest acrotretoid brachiopods from the lower Cambrian (Series 2) of South China,and its implications

The earliest growth of post‐metamorphic (post‐larval) shells in two species of Eohadrotreta is described from the Cambrian Shuijingtuo Formation of South China. Two different growth patterns can be observed by quantifying developmental variations in size and shape of successive stages of post‐metamorphic shell growth (including the pedicle foramen forming stage, pedicle foramen enclosing stage and intertrough increasing stage) of Eohadrotreta zhenbaensis and Eohadrotreta ? zhujiahensis . The pedicle foramen is never enclosed within the metamorphic shell of E. zhenbaensis , while the enclosed pedicle foramen of E .? zhujiahensis is located directly outside the metamorphic shell after the pedicle foramen enclosing stage. A strongly allometric growth pattern of E. zhenbaensis is demonstrated by the early enclosure of the pedicle foramen; an accelerated lengthening of the ventral intertrough is associated with the development of a more complex dorsal median septum during the intertrough increasing stage. By contrast, E .? zhujiahensis demonstrates possible paedomorphic development by delayed enclosure of pedicle foramen and an associated decreased lengthening of ventral intertrough during the intertrough increasing stage. This ontogenetic developmental sequence represents the marginal accretionary formation and growth of the pedicle foramen, which resembles that of linguloid brachiopods. Furthermore, the developmental process of the pedicle foramen of Eohadrotreta seems to recapitulate the likely evolutionary transition from the Botsfordiidae, with open delthyrium, to the Acrotheloidea, with an enclosed foramen. This study provides a unique opportunity to obtain a complete understanding of the ontogenetic development of the earliest acrotretoids, and casts new light on the phylogeny of lingulate brachiopods.     

Intraspecific variation of trunk segmentation in the oryctocephalid trilobite Duyunaspis duyunensis from the Cambrian (Stage 4, Series 2) of South China

A detailed exploration of growth and trunk segmentation of the oryctocephalid trilobite, Duyunaspis duyunensis Chang & Chien in Zhou et al. 1977, from the lower Cambrian (Stage 4, Series 2) Balang Formation in western Hunan Province, South China, is presented. Because of the excellent preservation, the complete post‐protaspid ontogenetic series from merapsid degree 0 to the holaspid phase is described. The ontogenetic series reveals new information on morphological changes such as the migration of the posterior branch of the facial sutures (from proparian to opisthoparian) and contraction of the posteromedial notch in the pygidium. The abundance of articulated specimens available from a narrow stratigraphical interval makes this material singularly useful for studying the morphogenesis and post‐embryonic growth of D. duyunensis in comparison with other oryctocephalids. Strong evidence that multiple numbers of pygidial segment are recognized in each meraspid degree as well as in the holaspid period showed unusual intraspecific variability in the rate of trunk segmentation, providing insights into how Cambrian subisopygous trilobites controlled their body patterning, including size, shape and trunk segment number in both thorax and caudal plate during growth.     

Character- and tree-based delimitation of species in the 'Cichlasoma' facetum group (Teleostei, Cichlidae) with the description of a new genus

The 'Cichlasoma' facetum group is part of the taxonomically complex group of Neotropical cichlid fishes of the tribe Heroini. Many species groups and unplaced species of heroines are still left without a generic name following the revision of the genus Cichlasoma . We describe here the 'Cichlasoma' facetum group as a new genus, Australoheros , and provide evidence for its monophyly based on phylogenetic analyses of morphological and mtDNA characters. Australoheros is morphologically characterized by the lowest values in meristic characters among heroines and by three apomorphic characters in coloration pattern. In addition to the three described species of Australoheros , our results of species delimitation based on a combination of tree- and character-based approaches identify seven putatively new species of Australoheros . Several coding schemes of morphological characters are used to recover the intrageneric relationships within the genus, resulting in very similar topologies. Discovery of additional species within the genus is expected once material from the whole distribution area is studied.     

Morphometric analysis of Tremadocian (earliest Ordovician) kirkocystid mitrates (Echinodermata, Stylophora) from the Taebaeksan Basin, Korea

Abundant isolated remains of stylophoran echinoderms (cornutes and mitrates) are reported for the first time in the late Tremadocian (Asaphellus Zone) Tumugol Formation of Korea. Mitrate remains include numerous adorals of Kirkocystidae. Several new important anatomical features have been observed on these adorals, as an internal calcitic layer that is associated to s₂ and possibly also to the palmar complex. This observation suggests that the palmar complex would be present not only in mitrocystitid mitrates, but also in peltocystitids. For the first time, several morphometric analyses have been undertaken based on isolated kirkocystid adorals, so as to explore the morphological diversity displayed by Korean adorals, but also in order to compare their morphology with that of other Gondwanan kirkocystids. Morphometric analyses indicate the occurrence of two contrasted morphologies within Korean adorals (morphotypes A and B), and of three distinct morphologies within European and North African forms (“Anatifopsis”, “Balanocystites”, and “escandei” morphotypes). Comparison of Korean adorals with those from Europe and North Africa shows that: (1) morphotypes B and “Anatifopsis” are equivalent; consequently, the two Korean specimens referred to morphotype B are assigned to the genus Anatifopsis; (2) morphology of most Korean adorals, which belong to morphotype A, is clearly distinct from that of all other described kirkocystids from Europe and North Africa. The small size, juvenile morphology, and great morphological variability observed in the morphotype A of the Korean adorals are suggestive of possible heterochronic processes (peramorphosis).     

A rare non‐trilobite artiopodan from the Guzhangian (Cambrian Series 3) Weeks Formation Konservat‐Lagerstätte in Utah,USA

We describe a weakly biomineralized non‐trilobite artiopodan arthropod from the Guzhangian Weeks Formation of Utah. Falcatamacaris bellua gen. et sp. nov. is typified by a thin calcitic cuticle, broad cephalon without eyes or dorsal ecdysial sutures, an elongate trunk with distinctively sickle‐shaped pleural spines and a long tailspine with a bifurcate termination. The precise affinities of Falcatamacaris gen. nov. are problematic due to the presence of unique features within Artiopoda, such as the peculiar morphology of the pleural and posterior regions of the trunk. Possible affinities with aglaspidid‐like arthropods and concilitergans are discussed based on the possession of 11 trunk tergites, edge‐to‐edge articulations and overall body spinosity. The new taxon highlights the importance of the Weeks Formation Konservat‐Lagerstätte for further understanding the diversity of extinct arthropod groups in the upper Cambrian.