Invertebrate Biology

Xiphosurids are an archaic group of aquatic chelicerate arthropods, generally known by the colloquial misnomer of ‘horseshoe crabs’. Known from marine envi- ronments as far back as the early Ordovician, horseshoe crabs are generally considered ‘living fossils’ – descendants of a bradytelic lineage exhibiting little morphological or ecological variation throughout geological time. However, xiphosurids are known from freshwater sediments in the Palaeozoic and Mesozoic; furthermore, the contention that xiphosurids show little morphological variation has never been tested empirically. Attempts to test this are hampered by the lack of a modern phylogenetic framework with which to explore different evolutionary scenarios. Here, I present a phylogenetic analysis of Xiphosurida and explore patterns of morphospace and environmental occupation of the group throughout the Phanerozoic. Xiphosurids are shown to have invaded non-marine environments indepen- dently at least five times throughout their evolutionary history, twice resulting in the radiation of major clades – bellinurines and austrolimulids – that occupied novel regions of morphospace. These clades show a convergent ecological pattern of differentiation, speciation and subse- quent extinction. Horseshoe crabs are shown to have a more dynamic and complex evolutionary history than previ- ously supposed, with the extant species representing only a fraction of the group’s past ecological and morphological diversity.

We explored differences in metabolic rates of the introduced snail Cornu aspersum collected from three distant coastal locations across a 1300 km latitudinal range in Chile and raised under common-garden conditions. We measured two proxies of metabolic rate: heart rate (f H) and CO 2 production (standard metabolic rate, SMR) in a flow-through respirometry system. Although both variables were significant-ly correlated (r 2 ¼ 0.49), suggesting that f H could be a predictor of SMR, the relationship between f H and SMR and also the CO 2 pulse (SMR/f H) varied across populations. Whereas SMR suggested an in-crease in energy metabolism towards high latitudes, supporting metabolic cold adaptation, f H indicated no trend (northern and southern populations exhibited the largest values). Our results suggest that, in invertebrates, energy metabolism cannot be inferred from heart rate. Our results show metabolic differ-entiation towards increased metabolic heat production in the southern location, warranting further analyses of functional differentiation in these introduced populations.

Crustaceans in the order Spinicaudata display a broad range of reproductive strategies, ranging from pure hermaphroditism to pure dioecy (separate males and females), and intermediate combinations. One particularly interesting genus of these "clam shrimps" is Eulimnadia. Based on offspring sex ratios, it has been suggested that all members of the genus are androdioecious: populations consist of mixtures of males and hermaphrodites. However, only two of the~40 species in this genus have been examined histologically to confirm the presence of ovotestes in the purported hermaphrodites of this group. Here, we report both sex ratio and histological evidence showing that populations of five additional Eulimnadia species from India and Thailand are indeed mixes of males and hermaphrodites (four species) or hermaphrodite only (one species). Sex ratios of adults and offspring from isolated hermaphrodites are in accordance with those previously reported for 15 Eulimnadia species, and histological assays of four of the five species show the presence of both testicular and ovarian tissue in these hermaphrodites. As has been previously reported, the testicular tissue in members of these Eulimnadia spp. is located in a small section at the distal end of the gonad. In addition, the sperm produced in these hermaphrodites forms distinct plaques of compacted chromatin. Overall, these data are consistent with a single origin of hermaphroditism in Eulimnadia, and support the notion that all members of the genus are either androdioecious or all-hermaphroditic.

The role of the offcuts of harvested kangaroos as a food source for native and introduced scavengers and detritivores was examined in the Roxby Downs region of arid South Australia. Corvids were the prominent users of offcuts in January and eagles and foxes significant users in September. Meat ants and a suite of carrion-specialist beetles and maggots also assisted with the decomposition of kangaroo offcuts. Harvested kangaroo populations provided a more reliable and better utilised food resource for scavengers and detritivores than did kangaroos that died naturally of heat stress. Kangaroo harvesting probably supports elevated populations of foxes, corvids, wedge-tailed eagles and detritivores. Therefore, kangaroo harvesters have a responsibility to control foxes, particularly in regions where endangered mammals or lambs are present. W R 0 2 0 5 1 F a t e o f k a n g a r o o h a r v e s t o f f c u t s i n a r i d A u s t r a l i a J . L . R e

BACKGROUND:
In spite of its indusrial usefulness and varied daily uses, lead (Pb) pollution is a widespread ecological problem that faces the humans in the 21th century. Pb was found to produces a wide range of toxic effects including neurotoxicity especially to the developing and young offspring. Recently, the utilization of herbal plants has received a significant attention where there has been rising awareness in their therapeutic use; among these is the garlic.
AIM OF THE WORK:
In light of the above, the current study is designed experimentally in female pregnant rats in order to investigate the beneficial role of garlic extract in the protection from the maternal and fetal cerebellar damage that produced by administration of different doses of Pb during pregnancy.
MATERIALS AND METHODS:
Positively pregnant female rats were divided into five groups; one control group, two Pb-treated groups (exposed to 160 and 320 mg/kg b.wt. of Pb, respectively) and two groups treated with both Pb and garlic (exposed to Pb as previous groups together with 250 mg/ kg b.wt. /day of garlic extract). Treatments started from day 1 till day 20 of pregnancy, where the mother rats of different experimental groups were sacrified to obtain the fetuses. Pb level in the maternal nd fetal blood and cerebellum was estimated by spectrophotometry. Specimens of the cerebellum of different mother and fetal groups were processed to histological and immunohistochemical staining for microscopic examination.
RESULTS:
The results showed that administration of Pb to pregnant rats resulted in a dose-dependent toxicity for both mothers and fetuses in the form of decrease of maternal weight gain, placental and fetal weights, brain weight and diminished fetal growth parameters, which were prominent in rat's group treated with larger dose of Pb. In Pb-treated rats, Pb level in blood and cerebellum was high when compared to the control. The histopathological examination of the cerebellum of treated dams and fetuses showed marked alterations mainly in the form of Purkinje cell degeneration and lack of deveopmet of fetal cerebellum. Co-treatment of garlic extract along with Pb resulted in a significant decrease in Pb levels as compared with those treated with Pb alone with improvement of the histopathological changes.
CONCLUSIONS:
This study was useful in evaluating the hazardous effects of uncontrolled use of Pb in general and in assessing the developmental and neurotoxicity of fetuses due to exposure during pregnancy in particular. Co-administration of garlic has beneficial effects in amelioration of Pb-induced neurotoxicity and reversing the histopathological changes of the cerebellum of mother rats and fetuses.
KEYWORDS:
garlic; glial fibrillary acidic protein; lead; purkinje cells

Eucaridan evolution involved a process starting from a body organization characterized by an elongate and cylindrical cephalothorax, a well-developed abdomen composed of swimming appendages, ending in a tail fan formed by flattened uropods and a telson. This process would lead, ultimately, to a body organization characterized by a shortened and depressed cephalothorax, and a reduced and ventrally folded abdomen. This ultimate process is typically known as carcinization, and is commonly defined as the process of becoming a crab. In this work, the evolution of the superorder Eucarida was studied using complex networks. A new definition of crab and carcinization are given based on the results obtained. A crab is a topological structural closure that determines the formation of a triadic central core. The evolution of the crab implied the formation of a triadic structure with high closeness centrality, formed by the cephalon, the fused thoracomere 1-4 and the carapace, which represented a highly stable hierarchical core deeply buried or enclosed in the topological structure of the network, responsible for the generation of a highly integrated and robust topology. Under this new definition, the representative of the infraorder Anomura used in this work, which is commonly considered as a crab, is not. This network seemed to be characterized by the presence of a quasi-dyadic structure, formed by the cephalon and the carapace, which was not sufficient for generating the topological closure.

We compared responses of adults and larvae of the brooding corals Pocillopora damicornis and Seriatopora hystrix to 12-h exposures to constant temperature treatments (211C, 281C, or 301C) and a treatment in which temperature fluctuated from 281 to 211C, simulating daily temperature variation generated by tidally driven upwelling in their natural habitat (Nanwan Bay, southern Taiwan). In all treatments, the maximum dark-adapted quantum yield of photosystem II (F V /F M ) of the larvae was B49% lower than that of adult corals; F V /F M in the larvae also differed among temperature treatments, with the highest values in the fluctuating treatment. These results show that the larvae of at least P. damicornis are more sensitive to temperature than adults, and suggest that larvae are physiologically well suited to fluctuating temperature regimes. To assess whether the timing of larval release affected their performance, larvae of P. damicornis were compared among release days within a single reproductive event. Groups of larvae released on nine consecutive days differed significantly in size, Symbiodinium content, and F V /F M . This demonstration of functional differences among coral larvae that are released on different dates within a single reproductive event creates the potential for advantages to accrue from the coincidence of larval phenotypes with temporally varying conditions. Adult colonies may experience selective advantages by producing broods of functionally variable larvae, in order to match extreme phenotypes to unusual environmental conditions.

Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535–520 million years ago (Ma)). The problematic fossil taxa Halkieria and Orthrozanclus (grouped in Sachitida) have been assigned variously to stem-group annelids, brachiopods , stem-group molluscs or stem-group aculiferans (Polyplacophora and Aplacophora), but their affinities have remained controversial owing to a lack of preserved diagnostic characters. Here we describe a new early sachitid, Calvapilosa kroegeri gen. et sp. nov. from the Fezouata biota of Morocco (Early Ordovician epoch, around 478 Ma). The new taxon is characterized by the presence of a single large anterior shell plate and polystichous radula bearing a median tooth and several lateral and uncinal teeth in more than 125 rows. Its flattened body is covered by hollow spinose sclerites, and a smooth, ventral girdle flanks an extensive mantle cavity. Phylogenetic analyses resolve C. kroegeri as a stem-group aculiferan together with other single-plated forms such as Maikhanella (Siphogonuchites) and Orthrozanclus; Halkieria is recovered closer to the aculiferan crown. These genera document the stepwise evolution of the aculiferan body plan from forms with a single, almost conchiferan-like shell through two-plated taxa such as Halkieria, to the eight-plated crown-group aculiferans. C. kroegeri therefore provides key evidence concerning the long debate about the crown molluscan affinities of sachitids. This new discovery strongly suggests that the possession of only a single calcareous shell plate and the presence of unmineralised sclerites are plesiomorphic (an ancestral trait) for the molluscan crown.

This three-volume work provides a complete study of this well-known group of animals, dealing with every level of their biological organization, from the molecular to the zoological.
    The leech, once so prominent in the history of medicine, is again being used widely in modern hospitals, especially in microsurgery. Revival in the use of leeches coincides with recent revelations about the rich diversity of pharmacologically active peptides secreted by the leech, including the powerful anticoagulant Hirudin which was discovered in 1884. The author who has studied  leeches extensively for many years, documents for the first time the scientific and biological rationale underlying the medical use of leeches and concludes that there was a nucleus of truth behind their use in previous centuries.
    In recent years the leech has been the subject of much neurobiological research, but such research has tended to emphasize the neurophysiological aspects. This book gives an authoritative account of leech neurobiology from the biological viewpoint, with emphasis on the neuronal basis and the evolution of leech behaviour.
    The book takes up Manton's controversial thesis that insects, myriapods and onychophorans constitute a new phylum (Uniramia) unrelated to the Crustacea. He also significantly extends the argument by proposing that leeches are also allied to the Uniramia. This proposal is a major intrusion into the traditional classification of the animal kingdom, and as such is likely to gain considerable attention.
    A 'key' to the leeches of each zoogeographical region of the world and an extensive bibliography (volume 3) are included.
    The diverse and wide-ranging nature of the book should make it of interest to research workers and students in various disciplines, particularly medicine, molecular biology, neurobiology, zoology and marine biology.
    Volume 1:    0 19 857377 4,  430 pages, 170 illustrations
    Volume 2:    0 19 857622 6,  430 pages, 170 illustrations
    Volume 3:    0 19 857623 4,  240 pages

Trabajo final para la materia Flora y Fauna Argentina de la EAN de Aves Argentinas donde se trabajó sobre el aspecto educativo y de investigacíón científica del arboretum "Árboles de Buenos Aires" ubicado en el parque "Presidente Sarmiento" de la Ciudad Autónoma de Buenos Aires.
El fin del trabajo es dar a conocer las características generales de los 3 ambientes originarios de la ciudad y parte de su vegetación, la cual ha sido implantada en ese espacio.

The illaenid trilobite Vysocania is widely represented in the Upper Ordovician of the Czech Republic, Portugal and Spain, and is one of the most characteristic taxa in the high-latitude peri-Gondwana palaeobiogeographical region to which it is endemic. Three species of the genus that were formerly assigned to Stenopareia and Zetillaenus, from the Czech Republic and Spain respectively, are herein revised, and a new species is described from the Czech Republic. The genus Octillaenus, of which a new species is described from the Upper Ordovician of Morocco, is considered to have arisen from Vysocania through paedomorphic (neotenic) processes. The relationships between Vysocania, Octillaenus, Stenopareia and Zetillaenus are reviewed and the criteria used in the definition of these taxa discussed. Species assigned to Vysocania are V. vaneki (type-species), V. iberica, V. moraveci sp. nov. and V. panderi; species assigned to Octillaenus are O. hisingeri (type-species) and O. marocanus sp. nov. Vysocania appears for the first time in the lower Berounian (Sandbian) and has its last undoubted record in the upper Berounian (upper Katian); Octillaenus is presently restricted to the Kralodvorian (upper Katian). •

Exceptionally preserved fossils from the Palaeozoic era provide crucial insights into arthropod evolution, with recent discoveries bringing phylogeny and character homology into sharp focus. Integral to such studies are anomalocaridids, a clade of stem arthropods whose remarkable morphology illuminates early arthropod relationships and Cambrian ecology. Although recent work has focused on the anomalocaridid head, the nature of their trunk has been debated widely.Here we describe new anomalocaridid specimens from the Early Ordovician Fezouata Biota of Morocco, which not only show well-preserved head appendages providing key ecological data, but also elucidate the nature of anomalocaridid trunk flaps, resolving their homology with arthropod trunk limbs. The new material shows that each trunk segment bears a separate dorsal and ventral pair of flaps, with a series of setal blades attached at the base of the dorsal flaps. Comparisons with other stem lineage arthropods indicate that anomalocaridid ventral flaps are homologous with lobopodous walking limbs and the endopod of the euarthropod biramous limb, whereas the dorsal flaps and associated setal blades are homologous with the flaps of gilled lobopodians (for example, Kerygmachela kierkegaardi,  Pambdelurion whittingtoni) and exites of the ‘Cambrian biramous limb’. This evidence shows that anomalocaridids represent a stage before the fusion of exite and endopod into the ‘Cambrian biramous limb’, confirming their basal placement in the euarthropod stem, rather than in the arthropod crown or with cycloneuralian worms. Unlike other anomalocaridids, the Fezouata taxon combines head appendages convergently adapted for filter-feeding with an unprecedented body length exceeding 2m, indicating a new direction in the feeding ecology of the clade. The evolution of giant filter-feeding anomalocaridids may reflect the establishment of highly developed planktic ecosystems during the Great Ordovician Biodiversification Event.

The systematic affinities of several Palaeozoic skeletal taxa were only resolved when their soft-tissue morphology was revealed by the discovery of exceptionally preserved specimens. The conodonts provide a classic example, their tooth-like elements having been assigned to various invertebrate and vertebrate groups for more than 125 years until the discovery of their soft tissues revealed them to be crown-group vertebrates. Machaeridians, which are virtually ubiquitous as shell plates in benthic marine shelly assemblages ranging from Early Ordovician (Late Tremadoc) to Carboniferous, have proved no less enigmatic. The Machaeridia comprise three distinct families of worm-like animals, united by the possession of a dorsal skeleton of calcite plates that is rarely found articulated. Since they were first described 150 years ago machaeridians have been allied with barnacles, echinoderms, molluscs or annelids. Here we describe a new machaeridian with preserved soft parts, including parapodia and chaetae, from the Upper Tremadoc of Morocco, demonstrating the annelid affinity of the group. This discovery shows that a lineage of annelids evolved a dorsal skeleton of calcareous plates early in their history; it also resolves the affinities of a group of problematic Palaeozoic invertebrates previously known only from isolated elements and occasional skeletal assemblages.

The renowned soft-bodied faunas of the Cambrian period, which
include the Burgess Shale, disappear from the fossil record in the late Middle Cambrian, after which the Palaeozoic fauna dominates. The disappearance of faunas of Burgess Shale type curtails the stratigraphic record of a number of iconic Cambrian taxa. One possible explanation for this loss is a major extinction, but more probably it reflects the absence of preservation of similar softbodied faunas in later periods. Here we report the discovery of numerous diverse soft-bodied assemblages in the Lower and
Upper Fezouata Formations (Lower Ordovician) of Morocco,
which include a range of remarkable stem-group morphologies
normally considered characteristic of the Cambrian. It is clear that biotas of Burgess Shale type persisted after the Cambrian and are preserved where suitable facies occur. The Fezouata biota provides a link between the Burgess Shale communities and the early stages of the Great Ordovician Biodiversification Event.

A new aglaspidid arthropod, Chlupacaris dubia gen. et sp. nov., is described from the Pusgillian (lower Ashgill, Upper Ordovician) Upper Tiouririne Formation near Erfoud, southeastern Morocco. Although disarticulated, careful documenting of the tergites allows a reconstruction of the exoskeleton to be made. Although somewhat trilobite-like in appearance, the lack of facial sutures, a well-defined axis with articulating half-rings and a pygidium clearly prove Chlupacaris gen. nov. is not a trilobite. An interesting feature is the presence of a hypostome in this non-trilobite arthropod. In contrast to other aglaspidids usually considered to be carnivorous, a filter-feeding mode of life is proposed for Chlupacaris gen. nov., based on the strongly vaulted cephalon, subvertical orientation of the hypostome and less strongly vaulted trunk. Chlupacaris gen. nov. is probably most closely related to the atypical aglaspidid Tremaglaspis unite from the Tremadoc (Lower Ordovician) of the U.K., but it can also be tentatively linked to the problematic Lower Cambrian arthropods Kodymirus vagans and Kockurus grandis from the Czech Republic. The relevance and validity of previous definitions and of possibly significant characters used for identifying aglaspidids are evaluated, and as a result, a new combination of characters diagnosing Aglaspidida is proposed. Contrary to previous reports, it is suggested that aglaspidids are probably more closely related to trilobites than they are to chelicerates. This notion may be supported by the shared possession of a mineralised cuticle, a possibly similar number of cephalic appendages, and the presence of a hypostome in some forms, although this last character may alternatively be homoplastic.

Anomalocaridids, giant lightly sclerotized invertebrate predators,
occur in a number of exceptionally preserved early and middle
Cambrian (542–501 million years ago) biotas and have come to
symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair ofanterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups—but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488–472 million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30 million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.

Integumentary system: "External covering of the organisms which distinguishes their internal environment from external environment; functionally, it protects from germs, injuries, and predator attacks is known as integument. The function that exercises by the integument is known as integumentary system." Every creature is variable in its nature and composition; their integument is as per their nature. Integument of unicellular invertebrates: Although the body system of protozoans and bacteria is quite simple, so their cell membrane corresponds to the integument. Integument of multicellular invertebrates: Structurally, multicellular organisms have complex body systems, so skin, secreting cells, epithelium cells, shell, scales, spikes spines, and syncytium are the various form of the integument. Protozoans: From a soft to a rigid body, protozoans cover all aspects. Radiolarian has a rigid body and bears spicules on the skin as a tegument. The body of some protozoans has secreting epithelial cells which lubricate and moisten their body. • Sponges: The horny appearance of some sponges is because of the spikes composed of calcium carbonate; additionally, some sponge's body is covered, internally and externally, with epithelium cells, named pinacoderm. • Mollusks: Some mollusks have ciliated epithelium that performs feeding in bivalve mollusks and gliding mechanisms in snails. Quinone tanned protein secreted by the glands for making the byssus thread anchor with the substratum and give away the risk of predation. Squids, cuttlefish, and octopuses have illuminating glands, while other cephalopods have pigment glands for coloration. Most of the mollusks have a shell that is composed of calcium carbonate. • Arthropods: The most successive species on the earth are arthropods just because of their cuticle, composed of chitin. Moreover, ecdysis or molting, the periodic shedding of old skeleton for growth, also occurs in arthropods. • Echinoderm: As per their variation in texture and body regulation, the tegument of the echinoderm is either horny, calcareous, slippery, pigmented, or hairy. In polyps, the tegument has horny coverings while the rest have calcareous. Moreover, anthozoans have a coral reef, covering made up of calcium carbonate. Some echinoderms have microvilli, flagella at their tegument for the filtration of water from germs. Gland cells, on the tegument, assist for the adhesion on the substrate; hence stinging and sensory cells prevent predators.

An updated checklist of the freshwater decapod species of Puerto Rico is presented based on records of shrimp and crab species whose presence has been confirmed in Puerto Rico as a result of extensive field collections, examination of carcinological collections, literature review, and personal communications from researchers. The freshwater decapods fauna of Puerto Rico consists of 18 species of shrimps belonging to eight genera and three families, and one species of crab belonging to the family Pseudothelphusidae.

One of the dogmas of comparative (evolutionary) immunology for the last few decades has been that all invertebrates lack any form of immunological memory similar to that found in jawed vertebrates. Vaccinating invertebrates, such as shrimp, should therefore be an ineffective management strategy resulting in no more than short-lived, non-specific immune stimulation. Recent studies in crustaceans and insects, however, suggest a form of immune memory in these animals described variously as ‘immune priming’, ‘specific immune priming’ or ‘line specific immune memory’. Workers have injected various arthropod species with inactivated pathogens and then later challenged them with a dose of the same pathogen capable of killing the host, reporting enhanced survival or increased reproductive fecundity compared with animals vaccinated with an unrelated organism. Interestingly, in some studies this enhanced immunity is trans-generational (i.e. passed on to progeny). This brief review focusses on a mechanistic exploration of ‘specific immune priming’ with particular reference to shrimp culture. Humoral antimicrobial factors, such as antimicrobial peptides and lysozyme, do not possess the required specificity to explain this phenomenon. Instead, recent studies have demonstrated elevated phagocytic activity after “vaccination” that does not result from general (non-specific) stimulation in phagocytosis. This enhanced phagocytic activity is likely linked to specific recognition of determinants on the outside of microbes by the haemocytes of these “vaccinated” animals. In some cases, at least, the mechanism for recognising these determinants appears to rely upon an invertebrate homologue of the Down syndrome cellular adhesion molecule (Dscam) and the ability of the Dscam gene to produce variants of this molecule with specific binding capabilities. Pioneering studies have demonstrated that Dscam is intricately involved in phagocytosis in insects and able to produce pathogen-specific splice form variants after immune challenge or infection. This would enable an animal to tailor an immune response specifically to a pathogen. It should be noted, however, that the phenomenon of immune priming is certainly not universal, possibly because of the much lower numbers of different immune receptors that arthropods are able to produce compared with jawed vertebrates. The review concludes that immune priming in invertebrates should be re-evaluated on an animal to animal and pathogen to pathogen basis. It also notes that whilst there is evidence that vaccinating shrimp against viral and bacterial infections shows promise, the practicality of such processes and their benefit to shrimp requires further evaluation.► Shrimp culture is affected by periodic viral and bacterial diseases. ► These diseases are difficult to control. ► This review examines approaches to ‘vaccination’ of crustaceans such as shrimp. ► Changes in the immune system of shrimp following vaccination are reviewed.

Abstract. Bivalve classification has suffered in the past from the crossed-purpose discussions among paleontologists and neontologists, and many have based their proposals on single character systems. More recently, molecular biologists have investigated bivalve relationships by using only gene sequence data, ignoring paleontological and neontological data. In the present study we have compiled morphological and anatomical data with mostly new molecular evidence to provide a more stable and robust phylogenetic estimate for bivalve molluscs. The data here compiled consist of a morphological data set of 183 characters, and a molecular data set from 3 loci: 2 nuclear ribosomal genes (18S rRNA and 28S rRNA), and 1 mitochondrial coding gene (cytochrome c oxidase subunit I), totaling ∼3 Kb of sequence data for 76 molluscs (62 bivalves and 14 outgroup taxa). The data have been analyzed separately and in combination by using the direct optimization method of Wheeler (1996), and they have been evaluated under 12 analytical schemes. The combined analysis supports the monophyly of bivalves, paraphyly of protobranchiate bivalves, and monophyly of Autolamellibranchiata, Pteriomorphia, Heteroconchia, Palaeoheterodonta, and Heterodonta s.l., which includes the monophyletic taxon Anomalodesmata. These analyses strongly support the conclusion that Anomalodesmata should not receive a class status, and that the heterodont orders Myoida and Veneroida are not monophyletic. Among the most stable results of the analysis are the monophyly of Palaeoheterodonta, grouping the extant trigoniids with the freshwater unionids, and the sister-group relationship of the heterodont families Astartidae and Carditidae, which together constitute the sister taxon to the remaining heterodont bivalves. Internal relationships of the main bivalve groups are discussed on the basis of node support and clade stability.

Exceptionally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat-Lagerstätte of major importance, and it is today considered as an 'Ordovician Burgess Shale.' This biota was discovered only some 15 years ago, but geological studies of the area date back to the beginning of the 20th century. Pioneering geological investigations lead to the discovery of Ordovician strata in the Anti-Atlas (1929) and ultimately resulted in their formal subdivision into four main strat-igraphic units (1942). In the Agdz area, the presence of fossiliferous Tremadocian (Lower Ordovician) strata was suspected as early as 1939, but only definitively confirmed in 1955. In the 1960s–1990s, Jacques Destombes provided the first detailed biostratigraphic framework for the Lower Ordovician of the Anti-Atlas, and collected thousands of fossils that were subsequently described in a series of monographs. In the early 2000s, exceptionally preserved fossils were discovered in the Fezouata Shale (Tremadocian–late Floian) in the central Anti-Atlas by Mohamed 'Ou Saïd' Ben Moula. This biota, now known as the Fezouata Biota, is of utmost importance, for it demonstrates the extent in the fossil record of non-biomineralising animals typical of the 'Cambrian Explosion' into the Ordovician, during the 'Great Ordovician Biodiversification.' Although most components are still in need of formal descriptions, a fairly good picture of the composition and organisation of this biota, and how it contributes to our understanding of the early evolution of metazoan communities, can now be depicted. Moreover, recent studies have substantially clarified the biostratigraphical and palaeoenvironmental context of the Fezouata Shale, and are now being followed up by detailed investigations of the taphonomy, geochemistry and micropalaeontology of this unique Konservat-Lagerstätte. These efforts will soon greatly benefit from the recovery of fresh, unweathered samples from drill cores.

Procambarus clarkii juveniles were used as an aquatic model to investigate growth performance
and immune parameters after 6 weeks of feeding with supplementation of ten experimental
diets containing 1%, 2%, 3% Biogen
(as probiotics), Allium sativum (garlic) and Cynodon
dactylon (as immunostimulant) and one concentration (3 g/L) of sodium alginate (as prebiotics),
compared with feeding on control basal diets only. All supplementation diets increased survival
rates and wet weight, while, 1% and 2% C. dactylon showed a significant (P 6 0.05) increase in
weight gain percentage (WG%), and specific growth rate (SGR). Feeding with diet containing
2% Biogen
, 2% and 3% garlic and sodium alginate showed a significant (P 6 0.05) increase in
SGR rate after 6 weeks. Synergetic effect of 1% and 3% Biogen
and sodium alginate in total
hemocytes count (THC) which increased significantly (P 6 0.05) after 6 weeks of feeding. Prophenoloxidase
activity increased with all supplemented diets. While SOD increased significantly with
3% C. dactylon, 1% and 3% garlic and 2% Biogen. The results indicated that Biogen
, garlic,
C. dactylon and sodium alginate inclusion with a basal diet had the potential to improve the growth
and immune response of P. clarkii juveniles, hence this enables us to use the three supplementation
diets in fish and prawn farms to improve their growth and immune parameters.
 2015 The Egyptian German Society for Zoology. Production and hosting by Elsevier B.V.

A cladistic analysis of 87 morphological and life history characters of medusozoan cnidarians, rooted with Anthozoa, results in the phylogenetic hypothesis (Anthozoa (Hydrozoa (Scyphozoa (Staurozoa, Cubozoa)))). Staurozoa is a new class of Cnidaria consisting of Stauromedusae and the fossil group Conulatae. Scyphozoa is redefined as including those medusozoans characterized by strobilation and ephyrae (Coronatae, Semaeostomeae, and Rhizostomeae). Within Hydrozoa, Limnomedusae is identified as either the earliest diverging hydrozoan lineage or as the basal group of either Trachylina (Actinulida (Trachymedusae (Narcomedusae, Laingiomedusae))) or Hydroidolina (Leptothecata (Siphonophorae, Anthoathecata)). Cladistic results are highly congruent with recently published phylogenetic analyses based on 18S molecular characters. We propose a phylogenetic classification of Medusozoa that is consistent with phylogenetic hypotheses based on our cladistic results, as well as those derived from 18S analyses. Optimization of the characters presented in this analysis are used to discuss evolutionary scenarios. The ancestral cnidarian probably had a sessile biradial polyp as an adult form. The medusa is inferred to be a synapomorphy of Medusozoa. However, the ancestral process (metamorphosis of the apical region of the polyp or lateral budding involving an entocodon) could not be inferred unequivocally. Similarly, character states for sense organs and nervous systems could not be inferred for the ancestral medusoid of Medusozoa.

While transplantation procedures are often associated with biomedical applications, they are also an invaluable tool for basic research. This review focuses on how transplantation techniques have been used to understand the biology of three large lophotrochozoan phyla: Annelida, Nemertea and Platyhelmintha. I describe how transplantation paradigms have uncovered fundamental principles regarding the embryology, immunology, endocrinology and regeneration biology of representative species within these three groups. In particular, embryologists have used blastomere transplantations to show that both mosaic and regulative development occurs in animals within the phyla. Immunologists have used transplantation techniques to demonstrate that these invertebrates mount a variety of innate immune responses, some of which include surprising features that classically characterize adaptive immunity. Endocrinologists have used transplantation experiments to uncover hormonal requirements for sexual development and maturation. Meanwhile, regeneration biologists continue to address fundamental questions regarding tissue polarity, post-embryonic patterning, stem cell physiology, and the role of the nervous system in regeneration. Along with recent technical and conceptual advances, transplantation remains a powerful tool for invertebrate research.

El Orden Trichoptera pertenece a los insectos acuáticos holometábolos (con estadios de huevo – larva – pupa – adulto) y se considera un grupo relacionado con el orden Lepidoptera (mariposas y polillas) (Holzenthal et al. 2007). A pesar de su semejanza como adultos, se distinguen porque las alas de Trichoptera son pilosas (cubiertas de pelos) y no escamosas como las de la mayoría de las mariposas y polillas; además sus partes bucales son reducidos (aunque con los palpos bien desarrollados) y nunca en forma de una probosis larga y enrollada, como lo es la lengua de las mariposas (Springer 2006). El nombre Trichoptera deriva del griego y precisamente significa alas peludas (Rincón & Pardo 1995; McCafferty 1998). Otra característica típica del orden son las antenas prominentes, las cuales pueden llegar a tener varias veces la longitud del cuerpo. Se conoce que la mayoría de los adultos son de hábito de vuelo vespertino cerca de los cuerpos de agua donde ocurren las larvas (Korytkowski 1995), aunque existen muchas especies de hábitos diurnos (McCafferty 1998). Se ha determinado a través de recolectas con trampas de luz negra o fluorescente que la mayor actividad de los adultos ocurre entre las 6-10 de la tarde (Rincón & Pardo 1995). En general, los adultos no se alimentan o únicamente absorben líquidos, y son de vida corta (pocos días).
Como es el caso en otros grupos de insectos acuáticos, los machos de algunas especies de tricópteros forman enjambres sobre el cuerpo de agua en horas de la tarde. La cópula se da sobre el sustrato. Los huevos son depositados por las hembras dentro o cerca del agua, ya sea en masas o hileras, a menudo envuelta en una masa gelatinosa. Las hembras de varias familias entran al agua y adhieren sus huevos en objetos sumergidos, mientras que en otras familias las masas de huevos pueden ser depositados sobre objetos fuera del agua y las larvas al nacer caen al agua. Además, las hembras de algunas especies vuelan tocando intermitentemente la superficie del agua para depositar las masas de huevos (McCafferty) 1998). Se conoce al menos una especie de América del Norte en la cual existen hembras ápteras (sin alas) en algún momento (Wiggins & Currie 2008).