Preservational folds simulating tergite junctions in tegopeltid and naraoiid arthropods

The exoskeleton in the Middle Cambrian Burgess Shale arthropod Tegopelte has previously been described as divided into tergites. Evidence from its sister taxon Saperion and from a Naraoia specimen from the Lower Cambrian Chengjiang fauna enables a reinterpretation of the suggested tergite boundaries in Tegopelte as preservational artefacts. They are considered here as folds that were formed during flattening of the undivided dorsal shield. As in the Naraoia specimen, the folds were initiated in the axial region between appendage pairs and then continue laterally. In Tegopelte and Saperion , segmentally arranged furrows in the axial region facilitated fold formation. Characters other than presence of thoracic tergites and pygidium must be used to assess the affinities of Tegopelte, Arthropoda, Tegopeltidae, tagmosis, segmentation, Chengjiang fauna, Burgess Shale.     

Evolutionary history of a secondary terrestrial Australian diving beetle (Coleoptera,Dytiscidae) reveals a lineage of high morphological and ecological plasticity

The evolution of a secondary terrestrial lifestyle in diving beetles (Coleoptera: Dytiscidae) has never been analysed in a phylogenetic framework before. Here we study Terradessus caecus Watts, a terrestrial species of the subfamily Hydroporinae endemic to Australia. We infer its phylogenetic placement using Bayesian inference and maximum‐likelihood methods based on a multilocus molecular dataset. We also investigate the divergence time estimates of this lineage using a Bayesian relaxed clock approach. Finally, we infer ancestral ecological preferences using a likelihood approach. We recover T. caecus nested in the genus Paroster Sharp with strong support. Therefore, we establish a synonymy for both species of Terradessus with Paroster: Paroster caecus (Watts) n.comb . and Paroster anophthalmus (Brancucci & Monteith) n.comb . Paroster is an endemic Australian genus that has a remarkable number of subterranean species in underground aquifers with highly derived morphologies. Our results highlight one of the most remarkable radiations of aquatic beetles with independent ecological pathways likely linked to palaeoclimatic disruptions in the Neogene. Paroster caecus (Watts) n.comb . originated from a mid‐Miocene split following the onset of an aridification episode that has been ongoing to the present day. The deep changes in ecological communities in association with the drying‐out of palaeodrainage systems might have pushed this lineage to colonize a new niche in terrestrial habitats.     

A peculiar climbing Megalonychidae from the Pleistocene of Peru and its implication for sloth history

The Xenarthra, particularly the Tardigrada, are with the Notoungulata and Marsupialia among the most diversified South American mammals. Lujanian South American Land Mammal Age localities from the coastal Piedra Escrita site and Andean Casa del Diablo Cave, Peru, have yielded three specimens of the Megalonychidae Diabolotherium nordenskioldi gen. nov. This singular fossil sloth exhibits a peculiar mosaic of cranial and postcranial characters. Some are considered convergent with those of other sloths (e.g. 5/4 quadrangular teeth, characteristic of Megatheriidae), whereas others clearly indicate climbing capabilities distinct from the suspensory mode of extant sloths. The arboreal mode of life of D. nordenskioldi is suggested by considerable mobility of the elbow, hip, and ankle joints, a posteriorly convex ulna with an olecranon shorter than in fossorial taxa, a radial notch that faces more anteriorly than in other fossil sloths and forms an obtuse angle with the coronoid process (which increases the range of pronation–supination), a proximodistally compressed scaphoid, and a wide range of digital flexion. D. nordenskioldi underscores the great adaptability of Tardigrada: an arboreally adapted form is now added to the already known terrestrial, subarboreal, and aquatic (marine and freshwater) fossil sloths. A preliminary phylogenetic analysis of the Tardigrada confirmed the monophyly of Megatherioidea, Nothrotheriidae, Megatheriidae, and Megalonychidae, in which Diabolotherium is strongly nested.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 179–235.     

Past and present diversity and distribution in the parasitic wasp family Megalyridae (Hymenoptera)

The phylogenetic relationships of extant and extinct Megalyridae are analysed at the genus level. The dataset comprises seven outgroup taxa, all eight extant genera and a number of extinct taxa that have been associated with Megalyridae, including two genera from Maimetshidae, whose affinity with Megalyridae is uncertain. Analytical results are unstable because some of the fossil taxa have many missing entries. The most stable results are produced when the maimetshid taxa and Cretodinapsis are excluded. When included, these taxa fall outside crown‐group Megalyridae, the maimetshid taxa being the sister of Orthogonalys (Trigonalidae). Based on the results of our analyses, we synonymize the fossil genera Rubes Perrichot n.syn . and Ukrainosa Perrichot & Perkovsky n.syn . with Prodinapsis, creating the new combinations Prodinapsis bruesi n.comb . and Prodinapsis prolata n.comb . When comparing past and present distributions of Megalyridae with the results of the phylogenetic analyses, it is evident that the genera radiated in the Mesozoic, and that the family as a whole was much more widespread then. The present‐day distribution is essentially relictual, with range contraction since the early Tertiary probably being the result of climate deterioration, which caused the disappearance of tropical forests throughout the Palaearctic.     

Chemical Properties and Physiological Actions of Crustacean Chromatophorotropins

The crustacean pigment-translocating hormones, the red pigment-concentratinghormone (RPCH), an octapeptide, and the light-adapting distalretinal pigment hormone (DRPH), an octadecapeptide, are thefirst invertebrate neurohormones to be fully characterized.Studies with both purified and synthetic hormones show that,in certain decapods, RPCH is a general pigment-concentratinghormone (PCH), affecting the pigments of all kinds of chromatophores(erythrophores, xanthophores, leucophores and melanophores);the DRPH seems to serve not only light-adapting function, butalso act as a general chromatophore pigment-dispersing hormone(PDH). The two hormones thus function as antagonists when regulatingthe color-adaptation of the decapod crustaceans. PCH activityis widely distributed within the arthropod endocrine systems.The first characterized insect neurohormones, the locust adipokinetichormones (AKH I and AKH II), show close structural similaritiesto the crustacean hormone, indicating a common evolution ofsome of the arthropod neurohormones. Physiological studies ofthe three hormones (RPCH, AKH I, and AKH II) and their syntheticanalogs show that they crossreact, i.e., they all exhibit pigment-concentratingactivity when tested on decapod crustaceans, adipokinetic activitywhen tested on locusts, and hyperglycemic activity when testedon cockroaches, although each of the hormones is more potentin its own system. Structure-function studies show, however,that quite different binding-site requirements exist for thehormones in activating their receptors on the various targettissues. The physiological specificity in their action thereforeseems to depend on a differential evolution of the hormone receptors.     

Studies of fossil hyaenids: the genera Hyaenictis Gaudry and Chasmaporthetes Hay, with a reconsideration of the Hyaenidae of Langebaanweg, South Africa

The fossil hyaenids from Langebaanweg in South Africa are revised taxonomically using both morphological comparisons and measurement data. Ictilherium preforfex is found to be a synonym of Ikelohyaena abronia . Other hyaenid taxa in this fauna are Hyaenictitherium namaquensis, Chasmaporthetes australis and a new taxon similar to Chasmaporthetes australis in the size and shape of the M₁, trigonid and other characters, but differing from this taxon in having short P₃ relative to P₂, a smaller anterior accessory cusp on P₄ and M₂, present. This taxon has previously been referred to Euryboas sp***, but comparison with Eurasian hyaenids indicates that it shares diagnostic characters with Hyaenictis graeca , type species of the genus Hyaenictis . This genus is poorly known and its content is reviewed. We find that only the new species from Langebaanweg, formally described as Hyaenictis hendeyi sp. nov. , and the Spanish Hyaenictis almerai probably belong in this genus, while other taxa intermittently referred to Hyaenictis belong to other genera. Thus, neither Leecyaena bosei nor Chasmaporthetes silberbergi belong in Hyaenictis .     

Systematics and biogeography of Australian rhopalosomatid wasps (Hymenoptera: Rhopalosomatidae) with a global synopsis of the enigmatic genus Olixon Cameron

Abstract The wasp family Rhopalosomatidae is represented in Australia only by the genus Olixon Cameron. Species of this genus have previously been considered rare based on material in collections and have rarely been observed in the field. All known species of Olixon are brachypterous, solitary ectoparasitoids of crickets (Orthoptera: Gryllidae). Prior to our study the world fauna comprised 11 species of which two were endemic to north‐eastern Australia. Based on specimens collected during recent intensive surveys in Australia we record 17 species for the continent. Fifteen of these species are described as new, which more than doubles the world fauna of Olixon: Olixon abrahami, O. danggari, O. ferrugineum, O. guyim, O. harveyi, O. helgae, O. jandakotae, O. jawoyn, O. jenningsi, O. kakadui, O. pilbara, O. wajuk, O. waldockae, O. wuthathi and O. zonale spp.n . Females of Olixon australiae Perkins and Olixon flavibase Townes are redescribed, and the male of O. flavibase is described for the first time. A key is provided for all 17 Australian species and their distribution is discussed. Results of a cladistic analysis of the world species of Olixon based on 41 morphological characters for 24 ingroup species are presented. The results obtained from equal and implied weighting parsimony analyses indicate that: (i) the Australian species of Olixon are not monophyletic, (ii) about three‐quarters of the Australian species form a monophyletic group, and (iii) a Central/South American Olixon is sister to all other species. The implications of these results for the biogeography of world Olixon species are briefly discussed.     

Protein Targeting into Secondary Plastids1

ABSTRACT. Most of the coding capacity of primary plastids is reserved for expressing some central components of the photosynthesis machinery and the translation apparatus. Thus, for the bulk of biochemical and cell biological reactions performed within the primary plastids, many nucleus‐encoded components have to be transported posttranslationally into the organelle. The same is true for plastids surrounded by more than two membranes, where additional cellular compartments have to be supplied with nucleus‐encoded proteins, leading to a corresponding increase in complexity of topogenic signals, transport and sorting machineries. In this review, we summarize recent progress in elucidating protein transport across up to five plastid membranes in plastids evolved in secondary endosymbiosis. Current data indicate that the mechanisms for protein transport across multiple membranes have evolved by altering pre‐existing ones to new requirements in secondary plastids.     

A critical look at the Treatise family-group classification of Conodonta: an exercise in eclecticism

The family-group classification of conodonts presented in the revised edition of the Treatise on Invertebrate Paleontology, Part W, Supplement 2, Conodonta, published in 1981, is shown to contain errors with regard to the International Code of Zoological Nomenclature. The classification lacks a concise philosophical and methodological foundation and exhibits very poor conceptualization of the taxa it recognizes. The classification is analyzed and discussed in terms of, among Linnkan taxonomists, generally accepted objectives and conventions with regard to the internal structure and phylogenetic message of a hierarchical natural classification. The obvious errors in terms of the ICZN are pointed out and corrected. As a demonstration of an alternative approach, a classification of the superfamilies Prioniodontacea, Hibbardellacea, and Icriodontacea is presented.