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.
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 (labrum, 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.
During an ostracod sampling campaign in the city of Munich (Germany) samples were taken from containers in a greenhouse of the Munich Botanical Garden. Beside the ubiquitous species Cypridopsis vidua ...(O. F. Müller, 1776), the samples contained four alien species, i.e., Chlamydotheca arcuata (Sars, 1901), Strandesia bicuspis (Claus, 1892), Tanycypris centa Chang, Lee & Smith, 2012, and Tanycypris alfonsi Nagler, Geist & Matzke-Karasz, 2014. While sorting the living Tanycypris specimens, a yet undescribed usage of the caudal rami was observed. Freshwater ostracods usually move on or in the sediment by using their first and second antennae, walking legs and - if not reduced - their caudal rami. During (non-swimming) locomotion of most freshwater ostracods with well-developed caudal rami, they help pushing the body forward by being used as a lever. This movement can be fast, but has never been reported to include sudden jumps. In contrast, both investigated Tanycypris species show an extraordinarily fast movement, especially when disturbed. Recordings with a high-speed camera were made, shooting horizontally into a 1.5-mm-thick micro-aquarium. The fast movement could be identified as a powerful jump, much resembling the movement of a catapult, propelled by a very rapid repulsion of the caudal rami from the ground. Although sized only around 1 mm, the observed specimens reached top speeds of up to 0.75 ms−1. Anatomically, this speed is obtained by the exceptional length of the caudal rami in Tanycypris, combined with a well-developed musculature, which stretches from a broadened posterior end of soft body along the so-called 'caudal rami attachment'. The jump itself resembles that of springtails or fleas, where the jump is powered by the energy previously stored in an elastic proteinaceous material; however, in Tanycypris no such mechanism could be detected and thus the energy for the catapult-like jump must be considered muscular, possibly aided by tendon-like structures and/or a mechanism involving a muscular pre-tension by a click-joint as recorded for Squillids.
The fossil record of Isopoda includes remains of presumed parasites. Among the fossils which have been discussed as potential parasites are those termed as Urda Münster, 1840. Some of these fossils ...have been discussed as possibly related to an extant group of parasites, Gnathiidae Leach, 1814. The type species of Urda – Urda rostrata Münster, 1840 – is herein interpreted as a close relative of the group Gnathiidae, based on the shared occurrence of a number of apomorphic features. This is with Urda punctata (Münster, 1842) herein being interpreted as a junior subjective synonym of U. rostrata. However, not all of the fossils associated with the name Urda can safely be identified as close relatives of Gnathiidae. Moreover, it is unclear whether the extinct species, which can be identified as close relatives of U. rostrata and Gnathiidae form a monophyletic group, as we could not identify an autapomorphy for a natural group Urda. A new species of close relatives of Urda rostrata and Gnathiidae – Urda buechneri n. sp. – is formally described based on μCT image data. Palaega suevica Reiff, 1936 and Palaega kessleri Reiff, 1936 are found to be subjective synonyms and are re-interpreted as Urda suevica n. comb. – a species closely related to U. rostrata. Due to the documented destruction of the holotype, a herein figured fossil specimen is designated as the neotype of Urda suevica. Palaega? stemmerbergensis Malzahn, 1968 is also interpreted as a close representative of U. rostrata and herein treated as Urda stemmerbergensis n. comb. Another already formally described species – Eobooralana rhodanica gen. et comb. nov. – is interpreted as a more distant relative, which is likely to be closer related to other extant species of Isopoda than those within Gnathiidae. For three species there are not enough characters preserved to interpret them as closely related to U. rostrata and Gnathiidae: Urda? liasica Frentzen, 1937 nom. dub. (type material destroyed, description insufficient for proper diagnosis), Urda? moravica Remeš, 1912 and Urda? zelandica Buckeridge and Johns, 1996.
El registro fósil de Isopoda incluye restos de posibles parásitos. Entre los fósiles que han sido discutidos como parásitos potenciales se encuentra Urda Münster, 1840. Algunos de estos fósiles han sido discutidos como posibles parientes de un grupo existente de parásitos, los Gnathiidae Leach, 1814. La especie tipo de Urda - Urda rostrata Münster, 1840 - es aquí interpretada como pariente cercano del grupo Gnathiidae, con base en la presencia común de un número de caracteres apomórficos. Esto incluye a Urda punctata (Münster, 1842) interpretada aquí como sinónimo junior subjetivo de U. rostrata. Sin embargo, no todos los fósiles asociados con el nombre Urda pueden ser indudablemente identificados como parientes cercanos a Gnathiidae. De manera adicional, no es aún claro si las expecies extintas, que podrían ser identificadas como cercanas a U. rostrata y Gnathiidae, forman un grupo monofilético, dado que no podemos identificar alguna autapomorfía para un grupo natural Urda. Una nueva especie de parientes cercanos a Urda rostrata y Gnathiidae - Urda buechneri n. sp. - es descrita formalmente con base en datos de imágenes μCT. Palaega suevica Reiff, 1936 y Palaega kessleri Reiff, 1936 son interpretados como sinónimos subjetivos y reinterpretados como Urda suevica n. comb. - como especies cercanamente relacionadas a U. rostrata. Debido a la documentada destrucción del holotipo, un ejemplar fósil aquí ilustrado, es designado como el neotipo de Urda suevica. Palaega? stemmerbergensis Malzahn, 1968 es también interpretada como como pariente cercano a U. rostrata y es tratada aquí como Urda stemmerbergensis n. comb. Otra especie ya descrita formalmente - Eobooralana rhodanica gen. et comb. nov. - es interpretada como un pariente más distante, quien probablemente se encuentra relacionada a otra especie viviente de Isopoda, que con los Gnathiidae. No existen caracteres suficientes preservados para tres especies, a fin de interpretarlas como cercanamente relacionadas a U. rostrata and Gnathiidae: Urda? liasica Frentzen, 1937 nom. dub. (material tipo destruído, descripción insuficiente para una adecuada diagnosis), Urda? moravica Remeš, 1912 y Urda? zelandica Buckeridge y Johns, 1996.
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.
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.
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.
The fossil record of Isopoda includes remains of presumed parasites. Among the fossils which have been discussed as potential parasites are those termed as Urda Münster, 1840. Some of these fossils ...have been discussed as possibly related to an extant group of parasites, Gnathiidae Leach, 1814. The type species of Urda – Urda rostrata Münster, 1840 – is herein interpreted as a close relative of the group Gnathiidae, based on the shared occurrence of a number of apomorphic features. This is with Urda punctata (Münster, 1842) herein being interpreted as a junior subjective synonym of U. rostrata. However, not all of the fossils associated with the name Urda can safely be identified as close relatives of Gnathiidae. Moreover, it is unclear whether the extinct species, which can be identified as close relatives of U. rostrata and Gnathiidae form a monophyletic group, as we could not identify an autapomorphy for a natural group Urda. A new species of close relatives of Urda rostrata and Gnathiidae – Urda buechneri n. sp. – is formally described based on µCT image data. Palaega suevica Reiff, 1936 and Palaega kessleri Reiff, 1936 are found to be subjective synonyms and are re-interpreted as Urda suevica n. comb. – a species closely related to U. rostrata. Due to the documented destruction of the holotype, a herein figured fossil specimen is designated as the neotype of Urda suevica. Palaega? stemmerbergensis Malzahn, 1968 is also interpreted as a close representative of U. rostrata and herein treated as Urda stemmerbergensis n. comb. Another already formally described species – Eobooralana rhodanica gen. et comb. nov. – is interpreted as a more distant relative, which is likely to be closer related to other extant species of Isopoda than those within Gnathiidae. For three species there are not enough characters preserved to interpret them as closely related to U. rostrata and Gnathiidae: Urda? liasica Frentzen, 1937 nom. dub. (type material destroyed, description insufficient for proper diagnosis), Urda? moravica Remeš, 1912 and Urda? zelandica Buckeridge and Johns, 1996.
Specimens of a new species of the non-marine ostracod genus, Tanycypris Triebel, 1959 were found in samples from water plant containers, displayed in a greenhouse of the botanical garden in Munich, ...Germany. Beside the ubiquitous species Cypridopsis vidua O.F. Müller, 1776, the samples contained four alien species of the subfamily Cypricercinae, namely Chlamydotheca arcuata Sars, 1901, Strandesia bicuspis Claus, 1892, Tanycypris centa Chang et al., 2012, and Tanycypris alfonsi n. sp.. The genus Tanycypris has mainly been reported (native) from Asia, and (invasive) from Italian rice fields. The Cypricercinae unite all species possessing a Triebel loop, a character of the caudal rami attachment. The subfamily is split into the tribes Cypricercini McKenzie, 1971, Bradleystrandesiini Savatenalinton & Martens, 2009 and Nealecypridini Savatenalinton & Martens, 2009, the latter of which comprises the genera Tanycypris Triebel, 1959, Astenocypris G.W. Müller, 1912, Diaphanocypris Würdig & Pinto, 1990 and Nealecypris Savatenalinton & Martens, 2009. During the process of describing the new species, a number of taxonomic uncertainties were detected within the genus Tanycypris, leading to a revision of the nine species currently ascribed to it: Tanycypris camaguinensis (Tressler, 1937), Tanycypris centa Chang et al., 2012 Tanycypris clavigera (G.W. Müller, 1898) (now: Nealecypris clavigera nov. comb.), Tanycypris madagascarensis (G.W. Müller, 1898), Tanycypris marina (Hartmann, 1965) (now: Dolerocypris marina nov. comb.), Tanycypris pedroensis (Tressler, 1950) (now: Diaphanocypris pedroensis nov. comb.), Tanycypris pellucida (Klie, 1932), Tanycypris siamensis Savatenalinton & Martens, 2009a, and Tanycypris telavivensis (Krampner, 1928) (now: Herpetocypris telavivensis). An identification key has been developed to the species of the genus Tanycypris.
Within Metazoa, it has been proposed that as many as two-thirds of all species are parasitic. This propensity towards parasitism is also reflected within insects, where several lineages independently ...evolved a parasitic lifestyle. Parasitic behaviour ranges from parasitic habits in the strict sense, but also includes parasitoid, phoretic or kleptoparasitic behaviour. Numerous insects are also the host for other parasitic insects or metazoans. Insects can also serve as vectors for numerous metazoan, protistan, bacterial and viral diseases. The fossil record can report this behaviour with direct (parasite associated with its host) or indirect evidence (insect with parasitic larva, isolated parasitic insect, pathological changes of host). The high abundance of parasitism in the fossil record of insects can reveal important aspects of parasitic lifestyles in various evolutionary lineages. For a comprehensive view on fossil parasitic insects, we discuss here different aspects, including phylogenetic systematics, functional morphology and a direct comparison of fossil and extant species.
Parasitic isopods have become specialised to many different host species and therefore show a wide variety of attachment and feeding specialisations. Often such structures are difficult to examine ...due to their small sizes which makes a more complete understanding of their functional morphology difficult. Here we present a new report and a first time high‐resolution, non‐SEM documentation of a parasitic epicaridean isopod, a female of the dajiid Arthrophryxus sp. from the Sea of Okhotsk. It was found during the SokhoBio 2015 on its host, a mysid shrimp (Holmsiella sp.). Arthrophryxus has only one formally described species, Arthrophryxus beringanus Richardson, 1908. With high‐resolution documentation methods, we reveal new details of the morphological structures of mouthparts and thoracopods of this dajiid. Furthermore, we discuss the functional morphology of attachment to the host and feeding according to our new findings. We suggest that the thoracopods are involved in the attachment process even more than formerly assumed for different dajiids. The piercing‐sucking mouthparts and the additional attachment mechanisms strongly indicate a permanent parasitism of the dajiid isopod. Permanent parasites affect the fitness of their hosts; therefore, deep‐sea forms of dajiid isopods have direct impact on the deep‐sea crustacean communities.
The larval phase of metazoans can be interpreted as a discrete post-embryonic period. Larvae have been usually considered to be small, yet some metazoans possess unusually large larvae, or giant ...larvae. Here, we report a possible case of such a giant larva from the Upper Jurassic Solnhofen Lithographic limestones (150 million years old, southern Germany), most likely representing an immature cirripede crustacean (barnacles and their relatives). The single specimen was documented with up-to-date imaging methods (macro-photography, stereo-photography, fluorescence photography, composite imaging) and compared with modern cirripede larvae. The identification is based on two conspicuous spine-like extensions in the anterior region of the specimen strongly resembling the so-called fronto-lateral horns, structures exclusively known from cirripede nauplius larvae. Notably, at 5 mm in length the specimen is unusually large for a cirripede nauplius. We therefore consider it to be a giant larva and discuss possible ecological and physiological mechanisms leading to the appearance of giant larvae in other lineages. Further findings of fossil larvae and especially nauplii might give new insights into larval evolution and plankton composition in the past.
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