Siphonophore

Bluesky Siphonophore Viewer

Posts now gather into a translucent siphonophore-like colony drifting through dark water. Oldest posts begin at one end of the spine and newer ones accumulate toward the other. Engagement thickens bells, membranes, and feeding clusters. Drag to orbit, mouse wheel to zoom, right-drag to pan, hover for a specimen overlay, click a segment to glide toward it, and double click the background to zoom to the whole organism.

Ecdysis

Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnants of the old, empty exoskeleton are called exuviae.

Description of a new species of the hyperparasitic barnacle <i>Duplorbis</i> Smith, 1906 and its cypris larva, with the molecular phylogenetic placement of the enigmatic family Duplorbidae Høeg & Rybakov, 1992 (Cirripedia: Rhizocephala)

Abstract Most species of Rhizocephala are obligate parasites of decapod crustaceans, but species in three families parasitize non-decapod hosts: Chthamalophilidae Bocquet-Védrine, 1961 (parasites of barnacles), Duplorbidae Høeg & Rybakov, 1992 (parasites of isopods and cumaceans), and Thompsoniidae Høeg & Rybakov, 1992 (mostly parasites of decapods but includes one species that is a parasite of stomatopods). Hyperparasitism (form of parasitism in which a secondary parasite lives on or in a primary parasite of a host) is extremely rare in Rhizocephala, but Duplorbis Smith, 1906, the type genus of the enigmatic family Duplorbidae, currently contains two named species hyperparasitic on bopyrid isopods (abdominal and branchial parasites of decapods) and one species on free-living isopods. A lectotype is selected for Duplorbis smithi Nierstrasz & Brender à Brandis, 1923. Recent work on the parasites of squat lobsters from New Zealand revealed a putative new species of this genus, described herein as Duplorbis korun. sp., hyperparasitic on branchial bopyrids of the genera Paragigantione Barnard, 1920 and Parapleurocryptella Bourdon, 1972. Each parasitized female bopyrid contained 3–8 externae of D. korun. sp. in the brood chamber. Externae of one host contained mature cypris larvae, a stage previously poorly known in this genus. These larvae are described herein using SEM and are shown to have a pair of long frontal filaments (retained from the nauplius stage), an exclusive feature shared among Duplorbidae. The first molecular (18S rRNA sequence) analysis of the family was also conducted. Duplorbids appear nested within a well-supported monophyletic lineage also comprising of Polyascidae Høeg & Glenner in Høeg, Noever, Rees, Crandall & Glenner, 2019, Polysaccidae Lützen & Takahashi, 1996, Clistosaccidae Boschma, 1928, Thompsoniidae Høeg & Rybakov, 1992, and Chthamalophilidae Bocquet-Védrine, 1961, most closely related to chthamalophilids. The discovery of this new species expands our knowledge of the species diversity, host use, and larval development of hyperparasitic rhizocephalans.

phylo — Mammalia — minomobi

phylo — Mammalia — minomobi

Bluesky Mutual Siphonophore Viewer

Public mutuals rendered as an organic colony. Center node is the target profile, and outer bells are verified mutual accounts.

samuelgoto/micropod

A small atproto PDS

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A common red algal origin of the apicomplexan, dinoflagellate, and heterokont plastids

The discovery of a nonphotosynthetic plastid in malaria and other apicomplexan parasites has sparked a contentious debate about its evolutionary origin. Molecular data have led to conflicting conclusions supporting either its green algal origin or red algal origin, perhaps in common with the plastid of related dinoflagellates. This distinction is critical to our understanding of apicomplexan evolution and the evolutionary history of endosymbiosis and photosynthesis; however, the two plastids are nearly impossible to compare due to their nonoverlapping information content. Here we describe the complete plastid genome sequences and plastid-associated data from two independent photosynthetic lineages represented by Chromera velia and an undescribed alga CCMP3155 that we show are closely related to apicomplexans. These plastids contain a suite of features retained in either apicomplexan (four plastid membranes, the ribosomal superoperon, conserved gene order) or dinoflagellate plastids (form II Rubisco acquired by horizontal transfer, transcript polyuridylylation, thylakoids stacked in triplets) and encode a full collective complement of their reduced gene sets. Together with whole plastid genome phylogenies, these characteristics provide multiple lines of evidence that the extant plastids of apicomplexans and dinoflagellates were inherited by linear descent from a common red algal endosymbiont. Our phylogenetic analyses also support their close relationship to plastids of heterokont algae, indicating they all derive from the same endosymbiosis. Altogether, these findings support a relatively simple path of linear descent for the evolution of photosynthesis in a large proportion of algae and emphasize plastid loss in several lineages (e.g., ciliates, Cryptosporidium , and Phytophthora) .

Symbiotic organs in insects: diversity, functional implications, and terminology

Abstract With over a million described species, insects represent the most successful group of animals on Earth. One of the drivers of insect diversity is their ability to engage in multifold beneficial symbioses with microorganisms, often involving specialized host organs to accommodate intra- or extracellular symbionts. The existence of such organs and their importance for sustaining and transmitting beneficial symbionts has been known for over a century, and specific terms have been established for categorizing organs harbouring intracellular bacteria (bacteriomes) or fungi (mycetomes), or cuticular crypts containing extracellular fungi (mycetangia). For others, however, general terms are lacking, e.g. organs containing extracellular bacteria associated with the cuticle or with the digestive tract. Furthermore, previously established terms have been misused in other contexts. Notably, ‘bacteriome’ has been increasingly employed in the microbiome field to refer to bacterial communities, instead of the term’s original meaning of specialized organs housing intracellular bacterial symbionts. Here, we review and categorize the diversity of symbiotic organs in insects and propose a unified terminology. Our hope is that this common language will facilitate communication and thereby support the field of symbiosis research in unravelling commonalities and differences in the evolution, ecology, development, physiology and molecular basis across symbiotic interactions. This article is part of the theme issue ‘Life in natural microcosms’.

Chondrilla nucula (Porifera, Demospongiae) : an example of successful plasticity ; ecological and morphological aspects

Sponges (Porifera) represent an important component of the Mediterranean sessile benthic community. They are present both in shallow and deeper waters, on soft and hard bottoms and some species, namely the bath sponges, has an application in human life since a long time. In the last few decades, they also assumed an importance among the organisms producing bioactive compounds which application goes from the homeopathy to the classical medicine to the industry. The study of the taxonomy, ecology and biology of sponges has an history hundreds years old. Now, due to the new findings that render sponges an exploitable marine resource, a coupling of the traditional sciences with the new emerging applications (biotechnology) is urgently needed. The Northern Adriatic Sea was the craddle of the sponge science hosting 36% of the sponge species present in the whole Mediterranean Sea. For the present work, the sponge fauna of a channel-like bay called Limski kanal (Croatia) has been intensively studied for the first time and a list of sponges, including species new for this area, is the result of a series of surveys in twelve sampling sites along the channel. As an introduction to the classification of sponges, a guide to the identification of the most common Mediterranean species has been written and included. A study on the temporal dynamic of a sponge community (Limski kanal, Croatia) was made by using fixed frames that have been photographed along a period of two years. Either seasonality, morphological variability, growth and degeneration phenomena have been observed, providing one more evidence of the incredible plasticity of the Porifera. Among the species in the Limski kanal, Chondrilla nucula (Porifera, Demospongiae) has been chosen as model organism. Firstly, its distribution, abundance and average coverage have been studied, showing that this species is very common along the channel, also in areas with a high sedimentation. Its distribution pattern depends mainly on light availability and kind of substrate. C. nucula is known as a very plastic species: here some macromorphological aspects related to the locomotion, the fragmentation events, the elimination of the sediment and the epibiosis are described in the attempt to give an overview on the successful life strategies of this sponge. Up to now only morphological studies on the oogenesis and spermatogenesis are available but the complete life cycle is unknown. In this study, macromorphological variations in specimens of C. nucula in reproduction and the first stages of embryogenesis have been described for the first time. Finally, in view of a biotechnological use of sponges as bioremediator organisms, the filtration and the bacterial retention rates of C. nucula have been investigated using clearance tests. In spite of a low filtration rate, the sponge showed high bacterial retention rates. This, together with the easy techniques required to farm it, makes of this sponge an eligible candidate for bioremediation. To achieve an effective conservation management plan and a sustainable exploitation of the marine resources, the knowledge on the biological and ecological characteristics of the benthic community and of the single species is absolutely necessary.

bisks.net — atprotozoa

A little zoo of tiny atproto experiments.

Mandible (insect mouthpart)

Insect mandibles are a pair of appendages near the insect's mouth, and the most anterior of the three pairs of oral appendages. Their function is typically to grasp, crush, or cut the insect's food, or to defend against predators or rivals. Insect mandibles, which appear to be evolutionarily derived from legs, move in the horizontal plane unlike those of vertebrates, which appear to be derived from gill arches and move vertically.

Earliest octopuses were giant top predators in Cretaceous oceans

Top predators drive changes in ecosystem structure. For the last ~370 million years, large-sized vertebrates have dominated the apex of the marine food chain, while invertebrates have served as smaller prey. Here we describe invertebrate top predators ...