168 million years old "marine lice" and the evolution of parasitism within isopods

BACKGROUND: Isopods (woodlice, slaters and their relatives) are common crustaceans and abundant in numerous habitats. They employ a variety of lifestyles including free-living scavengers and predators but also obligate parasites. This modern-day variability of lifestyles is not reflected in isopod fossils so far, mostly as the life habits of many fossil isopods are still unclear. A rather common group of fossil isopods is Urda (190-100 million years). Although some of the specimens of different species of Urda are considered well preserved, crucial characters for the interpretation of their lifestyle (and also of their phylogenetic position), have so far not been accessible. RESULTS: Using up-to-date imaging methods, we here present morphological details of the mouthparts and the thoracopods of 168 million years old specimens of Urda rostrata. Mouthparts are of a sucking-piercing-type morphology, similar to the mouthparts of representatives of ectoparasitic isopods in groups such as Aegidae or Cymothoidae. The thoracopods bear strong, curved dactyli most likely for attaching to a host. Therefore, mouthpart and thoracopod morphology indicate a parasitic lifestyle of Urda rostrata. Based on morphological details, Urda seems deeply nested within the parasitic isopods of the group Cymothoida. CONCLUSIONS: Similarities to Aegidae and Cymothoidae are interpreted as ancestral characters; Urda is more closely related to Gnathiidae, which is therefore also interpreted as an ingroup of Cymothoida. With this position Urda provides crucial information for our understanding of the evolution of parasitism within isopods. Finally, the specimens reported herein represent the oldest parasitic isopods known to date

168 million years old "marine lice" and the evolution of parasitism within isopods

BACKGROUND: Isopods (woodlice, slaters and their relatives) are common crustaceans and abundant in numerous habitats. They employ a variety of lifestyles including free-living scavengers and predators but also obligate parasites. This modern-day variability of lifestyles is not reflected in isopod fossils so far, mostly as the life habits of many fossil isopods are still unclear. A rather common group of fossil isopods is Urda (190-100 million years). Although some of the specimens of different species of Urda are considered well preserved, crucial characters for the interpretation of their lifestyle (and also of their phylogenetic position), have so far not been accessible. RESULTS: Using up-to-date imaging methods, we here present morphological details of the mouthparts and the thoracopods of 168 million years old specimens of Urda rostrata. Mouthparts are of a sucking-piercing-type morphology, similar to the mouthparts of representatives of ectoparasitic isopods in groups such as Aegidae or Cymothoidae. The thoracopods bear strong, curved dactyli most likely for attaching to a host. Therefore, mouthpart and thoracopod morphology indicate a parasitic lifestyle of Urda rostrata. Based on morphological details, Urda seems deeply nested within the parasitic isopods of the group Cymothoida. CONCLUSIONS: Similarities to Aegidae and Cymothoidae are interpreted as ancestral characters; Urda is more closely related to Gnathiidae, which is therefore also interpreted as an ingroup of Cymothoida. With this position Urda provides crucial information for our understanding of the evolution of parasitism within isopods. Finally, the specimens reported herein represent the oldest parasitic isopods known to date

Kontextorientiertes Dokumentenmanagement: Abschlußbericht Projekt ProWis

"Angestrebt wurden verfügbare und dokumentierte Archiv- und Dokumentenbestände, die an unterschiedlichen Orten genutzt werden können und übergreifend zugänglich sind. Durch die verbesserte Verfügbarkeit, Dokumentation und Strukturierungsmöglichkeit von Informationen sollten Aufträge besser, d.h. umfassender und schneller bearbeitet werden können. Beabsichtigt war, eine erweiterte Informationsbereitstellung in den Unternehmen einzuführen, die über den eigentlichen Datenaustausch hinausgehende Kooperationsmöglichkeiten bietet und die eine Übertragung eher impliziter Wissensaspekte und somit einen missverständnisfreieren Arbeitskontext ermöglicht. Durch die bessere Informationsbereitstellung sollte die Arbeit überschaubarer, planbarer und gestaltbarer werden. Die qualitative Verbesserung und die Umgestaltung von Arbeitsvorgängen sollte dadurch erreicht werden, dass unqualifizierte Sucharbeiten durch inhalts- bzw. auftragsbezogene Dienstleistungsarbeiten abgelöst werden. Die Steigerung der Prozess- und Ergebnisqualität in den Unternehmen sollte einen Beitrag zur Sicherung von Marktchancen und Wettbewerbsfähigkeit leisten." [Textauszug

The bigger, the better? Volume measurements of parasites and hosts: Parasitic barnacles (Cirripedia, Rhizocephala) and their decapod hosts

Rhizocephala, a group of parasitic castrators of other crustaceans, shows remarkable morphological adaptations to their lifestyle. The adult female parasite consists of a body that can be differentiated into two distinct regions: a sac-like structure containing the reproductive organs (the externa), and a trophic, root like system situated inside the hosts body (the interna). Parasitism results in the castration of their hosts, achieved by absorbing the entire reproductive energy of the host. Thus, the ratio of the host and parasite sizes is crucial for the understanding of the parasite's energetic cost. Using advanced imaging methods (micro-CT in conjunction with 3D modeling), we measured the volume of parasitic structures (externa, interna, egg mass, egg number, visceral mass) and the volume of the entire host. Our results show positive correlations between the volume of (1) entire rhizocephalan (externa + interna) and host body, (2) rhizocephalan externa and host body, (3) rhizocephalan visceral mass and rhizocephalan body, (4) egg mass and rhizocephalan externa, (5) rhizocephalan egg mass and their egg number. Comparing the rhizocephalan Sylon hippolytes, a parasite of caridean shrimps, and representatives of Peltogaster, parasites of hermit crabs, we could match their different traits on a reconstructed relationship. With this study we add new and significant information to our global understanding of the evolution of parasitic castrators, of interactions between a parasitic castrator and its host and of different parasitic strategies within parasitic castrators exemplified by rhizocephalans

Functional morphology of parasitic isopods: understanding morphological adaptations of attachment and feeding structures in Nerocila as a pre-requisite for reconstructing the evolution of Cymothoidae

Parasites significantly influence food webs and ecosystems and occur all over the world in almost every animal group. Within crustaceans there are numerous examples of ectoparasites;for example, representatives of the isopod group Cymothoidae. These obligatory parasitic isopods are relatively poorly studied regarding their functional morphology. Here we present new details of the morphological adaptations to parasitism of the cymothoiid ingroup Nerocila with up-to-date imaging methods (macro photography, stereo imaging, fluorescence photography, micro CT, and histology). Central aspects of the study were (1) the morphology of the mouthparts and (2) the attachment on the host, hence the morphology of the thoracopods. The mouthparts (labium, mandibles, paragnaths, maxillulae, maxillae, maxillipeds) form a distinct mouth cone and are most likely used for true sucking. The mouthparts are tightly "folded" around each other and provide functional rails for the only two moving mouthparts, mandible and maxillula. Both are not moving in, an ancestral-type median lateral movement, but are strongly tilted to move more in a proximal-distal axis. New details concerning the attachment demonstrate that the angular arrangement of the thoracopods is differentiated to impede removal by the host. The increased understanding of morphological adaptation to parasitism of modern forms will be useful in identifying disarticulated (not, attached to the host) fossil parasites

<i>Litholepas klausreschi </i>gen. et sp. nov., a new neolepadine barnacle (Cirripedia, Thoracica) on a sponge from the Upper Jurassic lithographic limestones of southern Germany

In this study we describe a unique fossil comprising 13 intact specimens of a pedunculate cirripede attached to a sponge (Codites serpentinus). The fossil comes from the Upper Jurassic lithographic limestones of southern Germany. Based on the shape and distinctive sculpture of the plates, a new genus and species Litholepas klausreschi gen. et sp. nov. (Eolepadidae: Neolepadinae) is introduced. Although lateral plates are indistinct and the rostrum is unknown, plate disposition and strong external sculpture indicate a position within Neolepadinae tough the exact relationships are still uncertain. Representatives of L.klausreschi gen. et sp. nov. are considered to have lived either in a parasitic or commensal relationship partially buried within the sponge

The bigger, the better? Volume measurements of parasites and hosts: Parasitic barnacles (Cirripedia, Rhizocephala) and their decapod hosts

Rhizocephala, a group of parasitic castrators of other crustaceans, shows remarkable morphological adaptations to their lifestyle. The adult female parasite consists of a body that can be differentiated into two distinct regions: a sac-like structure containing the reproductive organs (the externa), and a trophic, root like system situated inside the hosts body (the interna). Parasitism results in the castration of their hosts, achieved by absorbing the entire reproductive energy of the host. Thus, the ratio of the host and parasite sizes is crucial for the understanding of the parasite’s energetic cost. Using advanced imaging methods (micro-CT in conjunction with 3D modeling), we measured the volume of parasitic structures (externa, interna, egg mass, egg number, visceral mass) and the volume of the entire host. Our results show positive correlations between the volume of (1) entire rhizocephalan (externa + interna) and host body, (2) rhizocephalan externa and host body, (3) rhizocephalan visceral mass and rhizocephalan body, (4) egg mass and rhizocephalan externa, (5) rhizocephalan egg mass and their egg number. Comparing the rhizocephalan Sylon hippolytes, a parasite of caridean shrimps, and representatives of Peltogaster, parasites of hermit crabs, we could match their different traits on a reconstructed relationship. With this study we add new and significant information to our global understanding of the evolution of parasitic castrators, of interactions between a parasitic castrator and its host and of different parasitic strategies within parasitic castrators exemplified by rhizocephalans