Morphology and evolution of respiratory structures in the pleopod exopodites of terrestrial Isopoda (Crustacea, Isopoda, Oniscidea)

The morphology of the respiratory structures located in the pleopod exopodites of terrestrial Isopoda is described for representative species of different genera. Special emphasis is set on the evolution of these lungs in the context of phylogenetic relationships as revealed by other morphological characters. In the most primitive species of the Oniscidea, and still of subordinate taxa of the Crinocheta, respiration takes place in the thin ventral integument of the exopodites. The evolution of dorsal respiratory fields with a weakly wrinkled surface occurred at least six times within the Crinocheta. In five of these cases, a further development can be observed. The evolution of a partly covered respiratory field with strongly wrinkled surface may have taken place six times. It is assumed that completely internalized lungs with spiracles surrounded by a water‐repellent surface microsculpture, evolved at least six times independently within the Oniscidea: in the Tylidae, Actaecia, Aphiloscia, the Eubelidae, the Armadillidae and in a taxon probably comprising Porcellionidae plus Armadillidiidae.     

Mineral in skeletal elements of the terrestrial crustacean Porcellio scaber: SRμCT of function related distribution and changes during the moult cycle

Terrestrial isopods moult first the posterior and then the anterior half of the body, allowing for storage and recycling of CaCO₃. We used synchrotron-radiation microtomography to estimate mineral content within skeletal segments in sequential moulting stages of Porcellio scaber. The results suggest that all examined cuticular segments contribute to storage and recycling, however, to varying extents. The mineral within the hepatopancreas after moult suggests an uptake of mineral from the ingested exuviae. The total maximum loss of mineral was 46% for the anterior and 43% for the posterior cuticle. The time course of resorption of mineral and mineralisation of the new cuticle suggests storage and recycling of mineral in the posterior and anterior cuticle. The mineral in the anterior pereiopods decreases by 25% only. P. scaber has long legs and can run fast; therefore, a less mineralised and thus lightweight cuticle in pereiopods likely serves to lower energy consumption during escape behaviour. Differential demineralisation occurs in the head cuticle, in which the cornea of the complex eyes remains completely mineralised. The partes incisivae of the mandibles are mineralised before the old cuticle is demineralised and shed. Probably, this enables the animal to ingest the old exuviae after each half moult.     

Reproductive phenology of a natural population of Armadillidium pelagicum Arcangeli, 1955 (Isopoda, Oniscidea)

Armadillidium pelagicum, the most abundant species of the genus in Tunisia is endemic to the North of Tunisia and the circumsicilian islands. In the laboratory and under the natural conditions of temperature and photoperiod, virgin females of A. pelagicum exhibit a spontaneous ovarian maturation, followed by a parturial moult. Nevertheless, the onset of reproduction is greatly accelerated by the presence of a male. In fact, mating shortened the lag time (from the beginning of experiment to the parturial moult) by reducing the number of normal moult preceding the first parturial moult and the duration of the preparturial intermoult. In this species, only one mating is enough to ensure the fertility for several egg layings. Otherwise, it has been shown that A. pelagicum has a reproductive period rather than a reproductive activity and that mating females have a longer reproductive period than virgins. Like several species of terrestrial Isopods, the duration of the gestation period is temperature-dependent.     

Breeding patterns in the oniscid isopod,Porcellio ficulneus Verh., at high temperature and under different photophases

Summary

Porcellio ficulneus Verhoeff inhabits xeric Mediterranean grassland habitats. During winter vitellogenesis takes place and mancas are released in April. Under natural conditions some oocytes (about 20%) were lost. Both high temperature (25°C) at long or short photophases affected the reproductive pattern. Thus at 25°C and constant light vitellogenesis was markedly shorter than under field conditions. Oocytes matured sooner, but many were resorbed. The marsupium was formed earlier and contained fewer eggs. In some cases mancas that had developed could not emerge from the marsupium and died inside. In conclusion, P. ficulneus responds to warmer conditions by breeding earlier and reducing the number of offspring.     

The circulatory system in Phreatoicidea: implications for the isopod ground pattern and peracarid phylogeny

The circulatory systems of four species of Phreatoicidea and two species of Oniscidea were studied on the basis of serial semi-thin sections and a corrosion cast method. A 3D computer reconstruction was used to visualize the circulatory organs in the head of the Phreatoicidea. In the Phreatoicidea, the circulatory system consists of a longitudinal dorsal heart extending from the third thoracic to the border between the fourth and fifth pleonal segments. It is equipped with two pairs of asymmetrically arranged ostia, while five pairs of lateral cardiac arteries and an unpaired anterior aorta extend from the heart. Entering the head, the aorta is accompanied by the two first lateral arteries, which supply the muscles of the mandibles. Four pairs of arteries branch off the aorta to supply both pairs of antennae, the eyes, and sinuses in the head. In addition, several minute capillaries extend from the aorta to supply the brain. The two oniscidean species were re-investigated with regard to some characters which have been controversially discussed. In these species, the heart extends from the border between the fifth and sixth thoracic segments to the fifth pleonal segment. Five pairs of lateral cardiac arteries and the unpaired anterior aorta lead off the heart. A ventral vessel was not observed. The ground pattern of the circulatory system in isopods is reconstructed with greater reliability through optimisation of its characters based on proposed phylogenetic relationships. The results do not support a phylogenetic position of the Isopoda as basal Peracarida or even basal Eumalacostraca.     

A new family for the isopod crustacean genus Trident el la Richardson, 1905, with description of a new species from Fiji

A new family. Tridentellidae, is established for the genus Tridentella. T. vitae sp. nov. is described and figured and T. saxicola is recorded with figures. The phylogenetic position of the family is discussed, and notes provided on the natural history of the genus.     

Characterization of polymorphic microsatellite loci in the terrestrial isopod Armadillidium vulgare

The common pill bug, Armadillidium vulgare, is known to harbour two distinct strains of the feminizing proteobacteria Wolbachia. In order to study the effect of the presence of Wolbachia on the evolution of A. vulgare populations, we developed and characterized a set of nine polymorphic microsatellite loci from two microsatellite‐enriched genomic libraries. We screened 48 individuals from three French populations and found high genetic variation. Locus‐specific allelic diversity ranged from four to 28 and observed heterozygosity from 0.40 to 1.00, which indicates that these markers can be used to conduct population genetic studies in A. vulgare.     

朝鲜潮虫属一新种(甲壳纲:等足目)

记述采自江苏省连云港市花果山的等足目气肢虫科朝鲜潮虫属一新种,即花果山朝鲜潮虫Ｋｏｒｅｏｎｉｓｃｕｓ ｈｕａｇｕｏｓｈａｎｅｎｓｉｓ Ｔａｎｇ ｅｔ Ｇｕｉ,ｓｐ．ｎｏｖ．,并讨论其与相似种莱氏朝鲜潮虫Ｋｏｒｅｏｎｉｓｃｕｓ ｒａｃｏｖｉｔｚａｉ（Ａｒｃａｎｇｅｌｉ,１９２７）的区别。     

卷甲虫属一新种—三角卷甲虫：甲壳纲：等足目

本文记述采自江苏省昆山县的等足目卷甲虫科卷甲虫属一新种－三角卷甲虫Ａｒｍａｄｉｌｌｉｉｕｍｔｒｉａｎｇｕｌｅｓｐ．ｎｏｖ．讨论了同近似种寻常卷甲虫Ａｒｍａｄｉｌｌｉｄｉｕｍｖｕｌｇａｒｅ（Ｌａｔｒｅｉｌｌｅ,１８０４）的区别。     

The ultrastructure of the heart of Oniscus asellus L. and Asellus aquaticus L. (Crustacea,Isopoda)

Summary The endocardium of Oniscus asellus L. and Asellus aquaticus L. consists of lipid cells. The epicardium consists of a layer of cells with a vesiculated cytoplasm covered by a thick extracellular fibrous sheet. The myocardium is a single layer of cells, the sarcolemma invaginates at Z disc level forming transverse tubules, and longitudinal tubules branch off from these. At the A-I level' longitudinal tubules form transverse systems, which form couplings with the sarcoplasmic reticulum. The sarcoplasmic reticulum appears as perforated sheets enveloping the myofibrils. Two types of nerve terminal are found: one is embedded in a myocardial cell process, the other lies in a myocardial cell depression. They contain clear and dense-cored synaptic vesicles.This work was supported by grants from the Norwegian Research Council for Science and the Humanities     

中国海域团水虱属一新种(甲壳纲:等足目:团水虱科)

记述采自我国厦门及广东海门的团水虱科Sphaeromatidae一新种 ,中华团水虱Sphaeromasinensis。本种与采自海南岛的三口团水虱SphaeromatristeHeller相似 ,主要区别特征如下 :本种腹部前缘有 1个大突起 ,后者无 ;本种腹节具多个瘤状小突起 ,后者腹尾节则在近中部有 3对明显的大突起。正模标本♂ ,82F 83C ,1982年 4月 10日采自厦门何厝。模式标本保存在中国科学院海洋研究所标本馆。     

Muscle precursor cells in the developing limbs of two isopods (Crustacea, Peracarida): an immunohistochemical study using a novel monoclonal antibody against myosin heavy chain

In the hot debate on arthropod relationships, Crustaceans and the morphology of their appendages play a pivotal role. To gain new insights into how arthropod appendages evolved, developmental biologists recently have begun to examine the expression and function of Drosophila appendage genes in Crustaceans. However, cellular aspects of Crustacean limb development such as myogenesis are poorly understood in Crustaceans so that the interpretative context in which to analyse gene functions is still fragmentary. The goal of the present project was to analyse muscle development in Crustacean appendages, and to that end, monoclonal antibodies against arthropod muscle proteins were generated. One of these antibodies recognises certain isoforms of myosin heavy chain and strongly binds to muscle precursor cells in malacostracan Crustacea. We used this antibody to study myogenesis in two isopods, Porcellio scaber and Idotea balthica (Crustacea, Malacostraca, Peracarida), by immunohistochemistry. In these animals, muscles in the limbs originate from single muscle precursor cells, which subsequently grow to form multinucleated muscle precursors. The pattern of primordial muscles in the thoracic limbs was mapped, and results compared to muscle development in other Crustaceans and in insects. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

La reproduction saisonniére chez les isopodes terrestres: Contrôle photopériodique et neurohumoral

Summary

Seasonal reproduction in terrestrial Isopods is regulated by a neurohormone (VIH) synthesized in neurosecretory cells located in the protocerebrum median part. VIH restrains vitellogenin synthesis by the fat body. This inhibitory system is driven by the photoperiodic variations. Long days introduce a decrease in synthesis and—or—VIH release, allowing the oocytes to carry out the last vitellogenic phase. Other signals (mating, eggs in brood-pouch) tune the activity of the inhibitory system. Various aspects of photoperiodic and neurohormonal controls of reproduction are discussed: geographical variability and genetic determinism of the photoperiodic response; chemical nature, specificity and VIH mode of action; male physiology and VE synthesis, modalities of VIH synthesis and release.     

西双版纳地区的陆生等足类(甲壳亚门:等足目:潮虫亚目)

本文记述西双版纳地区陆生等足类１７种,包括７新种。新种模式标本保存于中国科学院动物研究所。种类名录如下。喜阴虫科Ｐｈｉｌｏｓｃｉｄａｅ 叶肢缅甸虫Ｂｕｒｍｏｎｉｓｃｕｓ ｌｏｂａｔｕｓ Ｋｗｏｎ ＆ Ｔａｉｔｉ,１９９３,勐仑缅甸虫,新种Ｂｕｒｍｏｎｉｓｃｕｓ ｍｅｎｇｌｕｎｅｎｓｉｓ ｓｐ．ｎｏｖ．,版纳缅甸虫,新种Ｂｕｒｍｏｎｉｓｃｕｓ ｂａｎｎｉｃｕｓ ｓｐ．ｎｏｖ．,易武缅甸虫,新种Ｂｕｒ