THE PHYLOGENY AND EVOLUTION OF SOME PHACOPID TRILOBITES

Abstract A data matrix of 32 characters, with a total of 132 character states and 48 terminal taxa of phacopid trilobites, was analysed using parsimony. The 108 most parsimonious trees have a length of 301 steps and a consistency index of 0.29. Two major clades were found, one including species referred to Acernaspis and one with species referred to Ananaspis, Paciphacops, Viaphacops , and Phacops . Most homoplasy occurs between the major clades of the trees, rather than within them. The major clades were also analysed separately, resulting in trees with significantly higher consistency indices. We redefine the following supraspecific taxa to make them monophyletic: Acernaspis, Ananaspis , and Paciphacops . In addition, Kainops , new genus, is described for a clade consisting of six taxa previously assigned to Ananaspis and Paciphacops . The evolutionary pattern resulting from our cladogram is compared with the approaches of Campbell and Eldredge, and it is argued that some of the assumptions made by these authors regarding the phylogeny of the group are not valid. The biogeography of the group was also analysed. It is found that phacopids from the Ludlow and older strata are distributed globally, with an emphasis, perhaps due to a large number of suitable localities, on Northern Europe. However, the lineage of phacopines leading up to Phacops is, with some slight exceptions, basically confined to the United States, being entirely absent in Northern Europe. The main phacopine lineage does not re-establish itself geographically until the middle Devonian. Finally, we analysed the evidence for polymorphism in phacopid trilobites, and reject this hypothesis on the basis of stratigraphy and the present cladogram.     

新疆巴里坤三塘湖志留纪三叶虫

新疆巴里坤三塘湖晚志留世阿苏山组三叶虫包括Ananaspis fecunda Barrande,Cheirurus barkolensis sp.nov.和Pacificurus sp.,与准噶尔盆地西北部乌图布拉格,哈萨克斯坦及捷克波西米亚的晚志留世三叶虫关系密切。另外对中国5个地区晚志留世三叶虫地层作了对比。Ananaspis,Pacificurus二属在中国是初次发现。     

A route to recovery: The early Silurian shallow-water shelly fauna in the northern Oslo basin

The shelly fauna of the lowest part of the Sælabonn Formation in the Hadeland district of the Oslo Region provides a rare insight into the shallow-water biota of the earliest Silurian and hence the start of biotic recovery after the end Ordovician extinction event. It is dominated by the brachiopods Dalmanella cf. pectinoides Bergström, Coolinia cf. columbana (Reed), Leptaena cf. haverfordensis Bancroft and Zygospiraella scotica (Salter) together with the trilobite Acernaspis elliptifrons (Esmark). The first three species in this unique association belong to eurytopic Ordovician survivor genera which were also present in the underlying unit in Hadeland and continued to thrive during the Silurian. Significantly, Zygospiraella and Acernaspis have no unequivocal Ordovician record but diversified rapidly and became common during the early Silurian (Rhuddanian) in many parts of the world. Moreover, Acernaspis and Zygospiraella were highly eurytopic, pioneer taxa that were among the first elements of the Rhuddanian shelly fauna to appear in many parts of the world especially around the margins of the remnant Iapetus Ocean, following the drowning of areas previously emergent during the late Ordovician sea-level lowstand. The Hadeland fauna provides evidence of a previously undocumented route (among several) by which life ultimately returned to the global diversity plateau established in the mid-Ordovician.     

Development of setal patterns in embryonic and adult aphids of the Hormaphidinae （Hemiptera： Aphididae）

The elementary traits and diversity of embryonic setal patterns of 31 species of 22 genera, in three tribes of Hormaphidinae are studied. The embryonic setal patterns to every species are provided. Based on the parsimony principle and the developmental principle, these patterns are analyzed in each tribe following the terminology of Richards （1965）. It is suggested that the setal patterns of abdominal tergites are the most important characters in embryonic and adult setal patterns. In conclusion, neoteny is a phylogenetic trend in the Hormaphidinae. Nipponaphidini and Hormaphidini have more typical neoteny in each genus and more diversity in different types of adult viviparous females than Cerataphidini, by showing more frequent and various protopatterns or mesopatterns.     

Ontogeny of cranial ossification in the eastern newt, Notophthalmus viridescens (Caudata: Salamandridae), and its relationship to metamorphosis and neoteny

The ontogenetic sequence of cranial osteogenesis through adulthood is described in samples of newts from completely metamorphosing and partially neotenic populations. Cranial ossification proceeds in the same sequence in both samples. Seven stages of cranial development are described on the basis of conspicuous events that occur during ontogeny. These include four larval stages, metamorphs, efts, and adults. Neotenic adults have skulls that are metamorphosed completely and indistinguishable from the skulls of non-neotenic adults. Neoteny in these newts does not involve the skull and is limited to the postmetamorphic retention of some gill structures and, thus, is termed "limited neoteny." The evolution of limited neoteny in newts as a correlated response to the inhibition of land-drive behavior is discussed.     

Silurian craniide brachiopods from Gotland

Seven craniide brachiopod genera are described from the Silurian (Wenlock–Ludlow) of Gotland, including one new genus and five new species. The new genus and species Thulecrania septicostata is unique among Silurian craniides as it possesses solid spines. The new species Lepidocrania multilamellosa is the first Silurian record of this poorly known Permian genus. The problematic North American Propatella Grubbs, 1939 , was originally described as a gastropod, but the new species Propatella palmaria from Gotland shows that it is a craniide with sutured hollow spines of a type not previously recorded from Silurian craniides. The dorsal valves of the new species Valdiviathyris? bicornis are remarkably similar to those of the type species and represent the first possible Palaeozoic record of this poorly known extant craniide. This first systematic study of craniide brachiopods from the Silurian of Gotland shows that the diversity is relatively high as compared to other known Silurian craniide faunas, but a more thorough comparison is not possible due to the lack of data from most parts of the world. The new data from Gotland support the view that the craniides were not affected by the end‐Ordovician extinction.     

Interstitial Dorvilleidae (Annelida, Polychaeta) from Europe, Australia and New Zealand

Four dorvilleid species new to science are described from intertidal and subtidal sandy sediments. For three of them new genera are erected: Coralliotrocha natans gen. et sp.n., Microdorvillea otagensis gen. et sp.n. and Pusillotrocha Åkessoni gen. et sp.n. One species represents the first record of the genus Pettiboneia from Australia, P. australiensis sp.n. Ophryotrocha minuta Levi, 1954 redescribed from Helgoland is transferred to a different genus, Arenotrocha gen.n. The present taxa belong to a morphological series of species with an increasing degree of neoteny in the family Dorvilleidae.     

The muscle scar in cavellinids and its importance for the phylogeny of platycope ostracodes

The adductor muscle scars of cavellinids from the Visean (in one case from the Upper Devonian) of the European part of the RSFSR have revealed a significant diversity in their morphology. Aggregate, multiserial with up to five series, bi- to triserial and nearly biserial muscle scars existed simultaneously. The verticaliserial muscle scars were initiated by a biserial larval group which in the course of evolution may have passed, due to neoteny, into the adult stage. Together with Cytherella sp. from Syria, the new data show that the genus Cytherella appeared not in Triassic nor Jurassic time, hut originated among cavellinids possibly in the Early Carboniferous. A new genus is Borovitchella , with the type species B. egorovi n. sp.     

Phylogenetic relationships and neotenic evolution of Metzgeriopsis (Lejeuneaceae) based on chloroplast DNA sequences and morphology

The systematic position of the enigmatic Asiatic liverwort Metzgeriopsis pusilla (Marchantiophyta), the single thalloid member of the largest family of leafy liverworts, Lejeuneaceae, was investigated based on sequences of the rbc L gene and the trn L-F region of chloroplast DNA, and morphology. Metzgeriopsis is not phylogenetically isolated from other taxa of Lejeuneaceae, as previously suggested, but is nested within Cololejeunea . The two genera share many morphological features, especially in the sporophyte generation, which is newly described. Metzgeriopsis and Cololejeunea are members of the Tuyamaella – Cololejeunea clade, characterized by neotenic features that probably evolved as adaptations to ephemeral habitats in tropical rain forests. Three different types of neoteny occur in this clade, which apparently originated by multiple heterochronic events. Within Lejeuneaceae, protonemal neoteny is unique to Metzgeriopsis and apparently resulted by evolution from a primary neotenic ancestor. The occurrence of protonemal neoteny in bryophytes is briefly reviewed and two types are recognized: species having a persistent thalloid protonema and species having a persistent filamentous protonema. The thalloid type is very rare and exclusive to epiphyllous liverworts, whereas the filamentous type is much more common and is characteristic of many terrestrial bryophytes, including the rare genus Protocephalozia . The new combination Cololejeunea metzgeriopsis (K.I.Goebel) comb. nov. is proposed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 293–308.     

鄂西志留纪早期三叶虫Latiproetus Lu,1962的新材料

本文描述湖北宜昌、兴山志留纪兰多维列世艾隆期蚜头虫类三叶虫Latiproetus latilimbatus(Grabau,1925)和Latiproetus tenuis Chang,1974的新材料.Latiproetus Lu,1962的有效性长期多有争论,通过新材料研究确认,该属和Prantlia P(r)ibyl,1946的区别在于其较短的鞍前区,向前收缩较少的头鞍,较微弱的尾肋沟和间肋沟,并不具鞍前区横脊.该属和Astroproetus Begg,1939的区别在于其较深的S1,清晰的S2,较小的活动颊刺,及宽而清晰的尾边缘.因此,笔者认为Latiproetus应为有效属.     

Ultrastructural and Other Observations Which Suggest Suctorian Affinities for the Taxonomically Enigmatic Ciliate Cyathodinium*

SYNOPSIS. Two species of the taxonomically enigmatic genus Cyathodinium, C. piriforme and C. cunhai, were studied in some detail at both light and electron microscopic levels. Data obtained strongly suggest suctorian affinities for the genus, since a number of structures or features are strikingly reminiscent of similar (if not homologous) structures recently discovered in ciliates belonging to the order Suctorida. Endosprits (suctorial tentacles?) of Cyathodinium show an arrangement of microtubules not unlike that known for several suctorians, especially Acineta and Tokophrya. Haptocysts or missile-like bodies, ca. 600 mμ long, have been observed within endosprits and free in the cytoplasm; again this is reminiscent of the complex organelles recently described from several suctorian groups. Mouthlessness, coupled with the presence of a ventral depression (functioning in gathering prey at distal ends of endosprits?) and the presence of food vacuoles in the cytoplasm, further support a suctorian mode of feeding. Finally, stages in the curious life cycle of Cyathodinium suggest neoteny and a basic similarity to endogenous budding processes in certain suctorians.     

Classification of uppermost Ordovician to Lower Devonian tubular and filamentous macerals from the Anglo-Welsh Basin

Dispersed tubes and filaments from the uppermost Ordovician, Silurian and Lower Devonian of the Anglo-Welsh Basin of Great Britain are described and classified using the artificial Anteturma system instituted for spores. The new Anteturma Trichomiformis is erected containing two new Turmae, Tubiformis and Filiformis. Within Tubiformis, the Infraturma Laevimurali, Endomurali and Extramurali are described, each containing a single genus with four, two and one species respectively. Within Filiformis, the Infraturma Ornatimurali is erected, based on a monospecific genus. Two assemblages of tubes and filaments are recognized. The older is found in uppermost Ordovician through to middle Silurian strata and is typified by a low diversity of smooth-walled tubes. The younger ranges from the middle Silurian at least to the Lower Devonian and is typified by various smooth-walled tubes, tubes with internal and external thickenings, and filaments. The majority of tubes and filaments are considered derived from the Nematophytales Lang.     

Paradox of peramorphic paedomorphosis: Heterochrony and human evolution

This paper reviews Gould's clock model for heterochronic processes and uses that model to develop simple matrix representations of growth and shape change. Matrix representations of growth and development provide a common formulation for all heterochronic processes. In particular, we show how neoteny can be diagnosed using such a matrix approach. The literature is rife with contradictory representations of how neoteny affects growth allometries and the timing of developmental events, and therefore of the role of neoteny in human evolution. Through the use of multivariate models, we explore these relationships and the internal consistency of opposing views. Gould's neoteny hypothesis for human evolution has been criticized for a number of reasons. Humans do not grow slowly. The slopes of our growth allometries show no common pattern of change vis-a-vis those of our closest relatives. Humans prolong rather than reduce rates of growth and development of body parts; the brain, for example, ceases growing later in humans than in apes, but during this prolonged period of early ontogeny, it grows at a rapid pace. This paper evaluates Gould's hypothesis and its critiques by focusing on particular questions. Does neoteny imply slow growth? Does it imply a unidirectional change in the rates of growth of traits? Under neoteny, should the brain cease growing in ancestor and descendant at the same age? Does prolongation of phases of growth and development confute neoteny? On the other hand, is paedomorphosis an inevitable consequence of prolonged growth and development? We show that, for all of these questions, the answer is no. © 1996 Wiley-Liss, Inc.     

The species of Pseudaphya (Teleostei: Gobiidae) and the evolution of aphyiine gobies

The Mediterranean gobiid genus Pseudaphya Iljin, 1930, formerly containing two nominal species, the type Ps. ferreri (O. De Buen & Page, 1908) and Ps. pelagica De Buen, 1931, is now believed to be monotypic after examination of Adriatic material originally identified as Gobius pusillus Canestrini, 1861. The last is here provisionally regarded as Pomato-schistus knerii (Steindachner, 1861). The genus Pseudaphya is redefined, with additional osteological features, and its single species, Ps. ferreri , redescribed. In comparison with other small transparent gobiids, Pseudaphya is shown to possess certain primitive features and a possible mode of evolution for this group of tiny gobies by neoteny from postlarvae of hill-stream sicydiines is discussed. An origin from less specialized gobiines seems more acceptable.     

浙江安吉志留纪真盔甲鱼类一新属

记述了浙江安吉地区志留纪真盔甲鱼类一新属——安吉鱼(新属)(Anjiaspis gen.nov.)。新属的主要特征是:中背孔呈纵长的滴水形,前端稍尖,距离头甲吻缘较远,后端圆钝,明显位于两眶孔前缘连线之前;眶孔较小,位置十分靠近头甲中线,并距离头甲后缘较近,眶孔前区长于眶孔后区;松果孔大致位于两眶孔中心连线上;感觉管系统大致呈格栅状分布,可见4条纵行干管及联络它们的横行管,横行管由侧横管和中横联络管组成,其数目均比较多;鳃囊6对,纹饰为均匀分布的细小粒状瘤点。在此基础上运用分支系统学的方法对其系统位置进行了探讨,结果表明,新属代表了真盔甲鱼类的最原始类型。     

Biological and stratigraphical significance of the Silurian nautiloid Aptychopsis

Turek, Vojtach 1978 04 15: Biological and stratigraphical significance of the Silurian nautiloid
Circular or elliptical structures described as the genus Aptychopsis Barrande 1872 (and mostly referred to the Crustacea) represent the opercula of a specialized group of orthoceratids. Their morphology bears a considerable resemblance to the structure of the lower jaws (aptychi) of some Mesozoic ammonoids, particularly of the genus Physodoceras . Because of its size and structure, however, Aptychopsis cannot have functioned as a jaw apparatus. Observation of an operculumin siru supports this assumption as regards its functional and systematic position. The classification of the genus Aptychopsis as given by Jones and Woodward (1872–1893) is purely typological and hardly applicable in palaeobiology. Continuous gradations exist between the various morphological types. The lack of systematically distinctive features explains the unsuitability of Aptychopsis for biostratigraphical use. Aptychopsids occur in the Silurian of Central Bohemia between the Spirograprus turriculatus Zone and the Neodiversograptus nilssoni Zone, inclusive, with maximum frequency in the uppermost Wenlockian.     

Ontogeny of the hyobranchial apparatus in the salamanders Ambystoma talpoideum (Ambystomatidae) and Notophthalmus viridescens (Salamandridae): The ecological morphology of two neotenic strategies

Comparison of metamorphosis of skull and hyobranchial system in two species of neotenic salamanders reveals two different types of neoteny. Ambystoma talpoideum is completely neotenic owing to delayed metamorphosis. Notophthalmus viridescens exhibits limited neoteny as a result of incomplete metamorphosis. Morphological details of neoteny are compared to life history in both species in order to discuss the ecological morphology of the two neotenic strategies. Comparisons to Taricha granulosa, Triturus vulgaris, and Ambystoma gracile indicate that these two strategies are widely employed and may represent familial patterns.     

NITROGEN ASSIMILATION AND ALLOCATION STRATEGIES OF POLAR SEAWEEDS FROM DIFFERING NUTRIENT ENVIRONMENTS

Halimedales (Chlorophyta) are widely distributed in reefs and lagoons throughout the tropics and subtropics. One genus, Chlorodesmis , consists of simple, branching siphons that persist into the mature sexual phase. In most other genera, only the juvenile stages exhibit such simple anatomy. Their mature, often-calcified thalli possess complex siphonal anatomy and differentiation depending on the location in the thallus. We obtained a nuclear ribosomal DNA phylogeny encompassing many genera in order to unravel the evolution of this complexity. Results pinpoint Caulerpa as outgroup to a clade with all other genera included in this study. The first dichotomy separates Halimeda from the remaining genera. Distinct gametangial anatomy defines these two principal clades. Within the remainder, Tydemania and its sister Flabellia are nearest neighbors to a clade containing Rhipocephalus , Udotea , Penicillus and Chlorodesmis. The latter three genera are polyphyletic. Therefore, character states of thallus superstructure defining these genera appear to be homoplasies. Chlorodesmis represents a case of neoteny where the juvenile stage persists into reproductive maturity. We will evaluate which morphological characters do change state in agreement with the molecular phylogeny and can, therefore, serve as diagnostic characters for a more natural classification.     

Eurytholia plates (Problematica) from the late Silurian of the Austrian Carnic Alps

A small fauna of phosphatic plates of the enigmatic organism Eurytholia bohemica [Ferretti A., Serpagli E., ?torch P., 2006. Problematic phosphatic plates from the Silurian-Early Devonian of Bohemia, Czech Republic. Journal of Paleontology 80 1026–1031.], is described for the first time from upper Silurian beds of Austria. Other known Silurian occurrences of this taxon were restricted to Bohemian localities even if the genus had been previously reported from several Ordovician outcrops. The extension of E. bohemica from the microcontinent of Perunica to that of Carnica suggests that Eurytholia was not an uncommon constituent of Silurian fauna, at least at intermediate latitudes in the southern hemisphere.