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Several adult female monstrilloid copepods, collected in March 2022 from the protected reef area of Xcalak, on the southern part of the Mexican Caribbean coast, proved to belong to two undescribed species of Monstrilla Dana, 1849. They are described here as M. xcalakensis sp. nov. and M. annulata sp. nov., partly by use of scanning electron microscopy. Females of the two species are generally similar but differ in: (1) antennular segmental structure, (2) antennular armature and ornamentation, (3) structure and setation of the fifth leg, (4) number and modifications of the caudal setae, and (5) integumental ornamentation. Comparison with congeneric species revealed distinctive features for both species that support their status as new. These two species are interesting additions to the reef-dwelling monstrilloid copepod fauna of the Mexican Caribbean and confirm Monstrilla as the most diverse genus of monstrilloids in this area, now represented by nine species.
The enigmatic ‘y-larvae’ (Thecostraca: Facetotecta) are microscopic marine planktonic crustaceans that were discovered more than a century ago, yet to this day their adults remain unknown. Despite occurring locally in large diversities, and therefore presumably being of ecological importance, only 17 species have been described globally, rendering it practically impossible to identify any y-larval specimen from any locality. The fact that species have been based on different life stages (nauplii and/or cyprids) further hampers identification. Y-larvae include many forms with planktotrophic (feeding) nauplii and even more with lecithotrophic (non-feeding) nauplii. At one coral-reef locality on the shore of Sesoko Island (Okinawa, Japan), extensive fieldwork in 2018 and 2019 confirmed an enormous taxonomic diversity of y-larvae there. Here, we present morphological diagnoses and an identification key for 34 lecithotrophic y-naupliar types (or morphospecies), which will correspond minimally to the same number of species when described. As a temporary measure, all are referred to by alphabetical parataxonomic designations, except for three that have been formally described already within the genus Hansenocaris Itô, 1985. To this should be added an additional 7–9 planktotrophic y-naupliar morphospecies, which are only treated briefly. Most often, y-larval taxonomy has been based on the cyprid stage, but the large morphological diversity of y-nauplii suggests that nauplii are at least as important for taxonomy. Lecithotrophic y-nauplii display a multitude of body shapes, the form-evolution of which is discussed here with reference to a recent molecular phylogeny of Facetotecta partly based on material from the same site. An indirect estimate of the relative abundances of all 34 lecithotrophic y-naupliar morphospecies is presented, based on laboratory-reared final-instar specimens. This treatment is intended as a step towards a proper taxonomy and a revised classification of Facetotecta, which will involve detailed descriptions of both nauplii and cyprids. Until such work progresses, the present overview of the y-naupliar fauna of a single Okinawan locality known to be a hotspot of y-larval diversity is offered as a baseline for further surveys of Facetotecta elsewhere in the Indo-West Pacific and beyond.
Taxonomic analysis of the genital plates and associated structures in Ophiuroidea (Echinodermata)
(2024)
Recently, new insights have been gained from the ophiuroid skeleton that were instrumental in the inference of a new phylogeny. The so far least studied ossicles are the adradial and abradial genital plates and the radial shields, which articulate with each other and support the genital slit and disc. In addition, the inner sides of the oral shields and madreporites have never been examined in detail. The present study utilized SEM, micro-CT and digital photography to document and examine these structures in 57 species from 28 of the currently accepted 34 families of Ophiuroidea. Early ontogeny and fossils were also considered. Previously, mainly the articular structures had been analysed, but the overall shape of the genital plates was here found to hold important phylogenetic signals. A long-neglected ossicle was re-discovered and studied in detail for the first time, here named the oral genital plate. It was recognized in all Ophintegrida, but was found to be absent in all Euryophiurida. The oral genital plate articulates with the oral shield and supports the proximal part of the genital slit wall. Abradial and oral genital plates were found to be absent in species that lack genital slits, but the adradial genital plate was always present. Numerous new morphological characters with potential phylogenetic signals were identified, described and figured in detail. A pre-existing character matrix was extended and revised with these new data, as well as with recently revised data on oral papillae, and a Bayesian phylogenetic analysis was performed. This phylogeny largely agrees with the current molecular hypothesis, but some branches were not supported.
Three new species of the genus Pelodera Schneider, 1866 viz., P. indica sp. nov., P. adeeli sp. nov. and P. paratretzeli sp. nov. collected from dung beetles and P. cylindrica (Cobb, 1898) collected from soil samples, are described and illustrated. Pelodera indica sp. nov. is characterised by sexual dimorphism in anterior region, cupola-shaped tail with a spike; males having punctated, striated and lobed bursa with no genital papillae originating anterior to cloaca. Pelodera adeeli sp. nov. is characterised by coarsely annulated cuticle; relatively narrow stoma; tail conoid without spike; males with punctated, lobed bursa and nine pairs of genital papillae arranged in a 2/1+2+P+3+1 configuration. Pelodera paratretzeli sp. nov. is characterised by sexual dimorphism in anterior region, stoma wide with three well-developed metastegostomal denticles; tail cupola-shaped with a long spike; males having spicules fused distally up to 12–14% of spicule length; bursa peloderan, anteriorly closed and punctated with nine pairs of genital papillae arranged in a 3/2+P+3+1 configuration. Pelodera cylindrica is described with additional details. The comparative analysis as well as phylogenetic relationship of the species belonging to the coarctata group have been elaborated by incorporating scanning electron microscopic observations. Information on the biogeographical distribution has also been provided.
When experienced in-person, engagement with art has been associated with positive outcomes in well-being and mental health. However, especially in the last decade, art viewing, cultural engagement, and even ‘trips’ to museums have begun to take place online, via computers, smartphones, tablets, or in virtual reality. Similarly, to what has been reported for in-person visits, online art engagements—easily accessible from personal devices—have also been associated to well-being impacts. However, a broader understanding of for whom and how online-delivered art might have well-being impacts is still lacking. In the present study, we used a Monet interactive art exhibition from Google Arts and Culture to deepen our understanding of the role of pleasure, meaning, and individual differences in the responsiveness to art. Beyond replicating the previous group-level effects, we confirmed our pre-registered hypothesis that trait-level inter-individual differences in aesthetic responsiveness predict some of the benefits that online art viewing has on well-being and further that such inter-individual differences at the trait level were mediated by subjective experiences of pleasure and especially meaningfulness felt during the online-art intervention. The role that participants' experiences play as a possible mechanism during art interventions is discussed in light of recent theoretical models.
Two species of the genus Ophelina Örsted, 1843 (Annelida, Opheliidae) are reported from the coast of Kuwait (Arabian Gulf) after specimens collected in the intertidal and shallow subtidal, namely Ophelina arabica sp. nov. and Ophelina grandis (Pillai, 1961). The new species is mainly characterised by features of the anal tube, which is provided with about 25 annulations at each side; the ventral margins are fully fused while dorsal margins are fused at most of their length but are free at the distal end in the shape of a conspicuous incision; the posterior end is opened with free margins; the anal tube also lacks marginal papillae but bears a pair of basal papillae and an unpaired anal cirrus attached to ventral margin at mid-length. Ophelina grandis is reported for the first time in the Arabian Gulf; specimens are fully described and compared with similar species. A key for species of Ophelina in the Indo-Pacific, Southern Asia, Indo-Malay Archipelago and Australia, is also provided.
Benthic samples were collected during two expeditions near the Antarctic Peninsula and in the South-Eastern Weddell Sea. During these studies, a new species of Ampharetidae Malmgren, 1867, Anobothrus konstantini Säring & Bick sp. nov., was found. Here we present a detailed description of this species. We used the traditional light microscope and scanning electron microscope (SEM) to identify and describe the diagnostic characters: a circular glandular band on segment 6; an elongate ridge between the notopodia on segment 12 and modified notochaetae on this segment; 16 thoracic, two intermediate and ten abdominal segments. For the first time, micro-computed tomography (micro-CT) was used for a species description of Anobothrus. Micro-CT provided information on the shape of the prostomium (Ampharete-type) and the arrangement of branchiae (four pairs in two rows, without a gap). In addition, we provide quantitative information on the environmental niche based on sediment parameters (chlorophyll a content, organic matter content, chloroplast equivalent, grain size) for the new Anobothrus species, relevant for, e.g., species distribution modelling. Finally, an identification key for all Anobothrus species is provided.
Six new species of Zaischnopsis Ashmead (Hymenoptera: Eupelmidae) from China are described, Zaischnopsis covid Jiang & Peng sp. nov., Zaischnopsis fuscolivida Tang & Peng sp. nov., Zaischnopsis lii Jiang & Peng sp. nov., Zaischnopsis pacis Jiang & Peng sp. nov., Zaischnopsis campaniformis Tang & Peng sp. nov., and Zaischnopsis zhongi Jiang & Peng sp. nov. All the new species are described and illustrated based on females, and partial mitochondrial cytochrome oxidase subunit I (COI) sequences are provided for the six new species as well as for the previously described Z. fumosa Peng & Xiang. Females of all the species of Zaischnopsis recorded from China are differentiated in a key.
Based on samples collected during the BIOICE project off Iceland, four species of marine annelids belonging to the family Pectinariidae were identified: Amphictene auricoma (O.F. Müller, 1776), Cistenides granulata (Linnaeus, 1767), Cistenides hyperborea Malmgren, 1865 and Lagis koreni Malmgren, 1866. Taxonomic remarks and data on geographical and bathymetric distribution are presented. The distribution of each species off Iceland was evaluated and two patterns were defined: C. granulata and C. hyperborea were mainly found in waters off the northeast coast, while A. auricoma and L. koreni were found on the southern coast. Several body characters with taxonomic value in this family were reviewed under the stereo microscope and scanning electron microscope, with special emphasis on the neuropodial uncini. Remarks on these special chaetae are included in the diagnoses.
Necropsies of Baltic grey (Halichoerus grypus) and ringed seals (Pusa hispida) presented a rare opportunity to study their acanthocephalan fauna. Both species hosted adults of three species of the genus Corynosoma Lühe, 1904, namely C. magdaleni Montreuil, 1958, C. semerme (Forsell, 1904) Lühe 1911 and C. strumosum (Rudolphi, 1802) Lühe 1904. A comparative morphological analysis of these three species of Corynosoma, combining both light and scanning electron microscopy, was performed for the first time. Sexual dimorphism in the size and shape of the trunk was observed in both C. magdaleni and C. semerme, but there was insufficient material to investigate this phenomenon in C. strumosum. Genital spines were not observed in any of the female acanthocephalans. Three possible explanations for the presence of genital spines in some females, but not others are (i) cryptic speciation, (ii) phenotypic variation and (iii) loss by extraction or shearing when the copulatory cap is released. Copulatory caps were observed on female C. semerme. The size and morphology showed considerable variability and all caps were strongly autofluoresecent.
Ampharete oculicirrata sp. nov. (Annelida: Ampharetidae) is described from samples collected by the Joint Nature Conservation Committee and Marine Scotland Science, in the West Shetland Shelf NCMPA in the NE Atlantic. This species is characterised by a very small body size, thin and slender paleae, twelve thoracic and eleven abdominal uncinigers, presence of eyes both in the prostomium and the pygidium, the latter provided with a pair of long lateral cirri. The external micro-morphology of the new taxon was studied using scanning electron microscopy and compared with species described or reported from the North Atlantic. Two complementary keys to all species of Ampharete in the area are also provided.
The new genus Neodiplopeltula gen. nov. is proposed to accommodate those species from the genus Diplopeltula Gerlach, 1950 that possess the following morphological characters: amphids in the shape of an elongated loop, a well-developed subcylindrical stoma and outstretched ovaries. The genus Diplopeltula is considered genus inquirendum et incertae sedis. Four species placed in Neodiplopeltula gen. nov. are redescribed. The following taxonomic changes are proposed: Neodiplopeltula asymmetrica (Allgén, 1935) gen. et comb. nov.; Neodiplopeltula barentsi (Steiner, 1916) gen. et comb. nov.; Neodiplopeltula bathmanni (Jensen, 1991) gen. et comb. nov.; Neodiplopeltula cuspidiboja (Leduc, 2017) gen. et comb. nov.; Neodiplopeltula indica (Gerlach, 1962) gen. et comb. nov.; Neodiplopeltula intermedia (Gerlach, 1954) gen. et comb. nov.; Neodiplopeltula obesa (Nguyen Vu Thahn, Nguyen Thahn Hien & Gagarin, 2012) gen. et comb. nov.; Neodiplopeltula onusta (Wieser, 1956) gen. et comb. nov.; Neodiplopeltula ovalis (Ditlevsen, 1928) gen. et comb. nov. and Neodiplopeltula tchesunovi (Fadeeva & Mordukhovich, 2013) gen. et comb. nov. New synonyms include: Diplopeltis asymmetricus Allgén, 1935 and Diplopeltis ovalis Ditlevsen, 1928 are synonimised with Neodiplopeltula barentsi (Steiner, 1916) gen. et comb. nov.; Diplopeltula tchesunovi Fadeeva & Mordukhovich, 2013 is synonimised with Neodiplopeltula onusta (Wieser, 1956) gen. et comb. nov.; the male of Diplopeltula cuspidiboja Leduc, 2017 is synonimised with Neodiplopeltula barentsi gen. et comb. nov. and the female with N. bathmanni gen. et comb. nov. A key to the species of Neodiplopeltula gen. nov. is provided.
Eight species of Diplopeltoides are described from the Swedish west coast. Diplopeltoides suecicus sp. nov. has the cuticle with longitudinal striation visible only under SEM; cuticular plate underlying the cephalic cuticle around the amphid present; cephalic sensilla 4–6 μm long; amphid an inverted U-shape; wide space between amphidial branches areolated; spicules 27–31 μm long; gubernaculum with caudal apophysis. Diplopeltoides longicaudatus sp. nov. is characterized by a cuticle without longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 13 μm long; amphid an inverted U-shape; narrow space between amphidial branches not ornamented; spicules unequal in size, 27–31 μm long; gubernaculum absent; midventral precloacal cuticular ridge present. D. grandis sp. nov. is characterized by a cuticle with longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 18.5 μm long; amphid an inverted U-shape; wide space between amphidial branches punctate. The following taxonomic changes are proposed: Diplopeltoides asetosus (Juario, 1974) comb. nov., Diplopeltoides botulus (Wieser, 1959) comb. nov., Diplopeltoides bulbosus (Vitiello, 1972) comb. nov., Diplopeltoides lucanicus (Boucher & Helléouët, 1977) comb. nov., Diplopeltoides pumilus (Vincx & Gourbault, 1992) comb. nov. and Diplopeltoides striatus (Gerlach, 1956) comb. nov. Diplopeltoides holovachovi Fadeeva & Mordukhovich, 2013 is synonymised with Diplopeltoides pumilus comb. nov. An updated key to the species of Diplopeltoides is provided.
We provide the current holdings of Meropeidae in the Florida State Collection of Arthropods (FSCA). To date, FSCA holds a well-curated collection of extant meropeids representing 17 U.S. states and Western Australia (n = 316 Merope tuber Newman, fi ve Austromerope poultoni Killington). Merope tuber records from Vermont, Texas, and South Carolina are published here for the fi rst time. A total of 298 pinned M. tuber and four pinned
A. poultoni; six M. tuber specimens preserved in 95% ethanol; and 12 M. tuber and one A. poultoni sputter-coated with gold-palladium for SEM are available for researchers interested in studying this unique family of insects.
Knowledge about the taxonomy and distribution of the monogeneric polychaete family Longosomatidae Hartman, 1944 is limited in all parts of the world. A new species of the genus Heterospio Ehlers, 1874 (Annelida, Longosomatidae) is described from the Indian Ocean. Heterospio indica sp. nov. is mainly characterised by the conspicuous flattening of the distal half of capillary chaetae located in anterior elongated segments. Several body characters of high taxonomic relevance in the genus are examined under the SEM and discussed. The 18S SSU rDNA and COI genes were sequenced and represent the first sequencing of a species of Heterospio, and the sequences have been deposited in GenBank.
Two new species of the genus Sectonema from natural habitats of northern Vietnam are studied. This paper includes their descriptions, measurements, line illustrations, and light microscope (LM) and scanning electron microscope (SEM) pictures. Sectonema tropicum sp. nov. is characterized by a 2.56– 3.24 mm long body, 19–21 μm broad lip region, odontostyle 20–21 μm long at its ventral side, 730– 834 μm long neck, pharyngeal expansion occupying 52–59% of total neck length, uterus a simple tube-like structure 150–242 μm long or 1.2–2.5 times the body diameter, pars refringens vaginae present, V = 48–52, short (31–40 μm, c = 70–91, c’ = 0.5–0.6) and rounded tail, 91–97 μm long spicules, and only one weakly developed ventromedian supplement. Sectonema vietnamense sp. nov. is characterized by its slender (a = 33–49) and 2.71–4.25 mm long body, 14–16 μm broad lip region, odontostyle 8–9 μm long at its ventral side, 716–918 μm long neck, pharyngeal expansion occupying 63–67% of total neck length, uterus simple and 209–242 μm long or 2.5–2.9 times the corresponding body diameter, pars refringens vaginae absent, V = 54, short (34–39 μm, c = 70–115, c’ = 0.6–0.8) and rounded tail, 59–75 μm long spicules, and three or four irregularly spaced ventromedian supplements bearing hiatus. Both species are also characterized by their nearly continuous lip region, an atypical feature in this genus. Molecular analysis of S. tropicum sp. nov. confirms that Sectonema is a natural (monophyletic) taxon, very close to Metaporcelaimus.
A new protocol to prepare material of Coccoidea (Insecta: Hemiptera) for observation with scanning electron microscopy is presented. This technique consists of cleaning samples (stored in 96% alcohol) with acetone and xylene, taking them directly to the hydration step, and subsequently dehydrating them in alcohol. Fixation in glutaraldehyde and post-fi xation in osmium tetroxide are omitted. The cleaning of the samples and the correct critical point dryer are very important.
A new species of Paracrobeles, P. kelsodunensis sp. nov. is described from the Kelso Dunes area, Mojave National Preserve, southern California. Paracrobeles kelsodunensis sp. nov. is particularly characterised by a body length of 469–626 μm in females and 463–569 μm in males; lateral field with four incisures, extending almost to tail terminus; three pairs of asymmetrical lips, separated by U-shaped primary axils with two long guarding processes, each lip usually with four tines along its margin; three long labial probolae, deeply bifurcated, with slender prongs without tines; metastegostom with a strong anteriorly directed dorsal tooth; pharyngeal corpus anteriorly spindle-shaped, posteriorly elongate bulbous with dilated lumen; spermatheca 24–87 μm long; postvulval uterine sac 60–133 μm long; vulva in a sunken area; spicules 33–38 μm long; and male tail with a 5–8 μm long mucro. The generic diagnosis is emended on the basis of recently described species and a key to the species of Paracrobeles is provided.
Populations of Stegelleta are described from California, New Zealand and Senegal. An amphimictic population from California is identified as belonging to S. incisa and compared with type specimens from Utah and an amphimictic population from Italy. One population from New Zealand is close to S. incisa but considered to represent a new species, Stegelleta laterocornuta sp. nov. It is particularly characterised by a 379–512 μm long body in females and 365–476 μm in males; cuticle divided into 16 rows of blocks at midbody (excluding lateral field); lateral field with four incisures; three pairs of asymmetrical lips, U-shaped primary axils without guarding processes, each lip asymmetrically rectangular with a smooth margin, only lateral lips have slender acute tines; three labial probolae, bifurcated at half of their length; vulva without flap; spermatheca 17–31 μm long; postuterine sac 7–24 μm long; spicules 21.5–23.5 μm long. Other specimens from New Zealand are identified as belonging to S. tuarua. A parthenogenetic population from Senegal is identified as belonging to S. ophioglossa and compared with type specimens from Mongolia and records of several other populations of S. ophioglossa. The generic diagnosis is emended and a key to the species of Stegelleta is provided.
Die vorliegende Arbeit befasst sich mit der übergeordneten Frage nach dem Einfluss der Multikollinearität bei der Spezifikation und Schätzung von latenten nichtlinearen Effekten in Strukturgleichungsmodellen. Da das Multikollinearitätsproblem in latenten nicht-linearen Strukturgleichungsmodellen bisher in der Literatur kaum Beachtung gefunden hat, wird als erstes die Frage beantwortet, welche Relevanz das Vorliegen von Multikollinearität in nichtlinearen Strukturgleichungsmodellen hat. Dabei wird aufgezeigt, dass Multikollinearität von Prädiktoren nicht nur bei linearen Strukturgleichungsmodellen ein Problem darstellt, sondern vor allem bei nicht-linearen Strukturgleichungsmodellen aufgrund des Vorhandenseins nicht-linearer Terme. Da nicht-lineare Terme untereinander in einem höheren Zusammenhang stehen können als lineare Terme eines Strukturmodells, kann es zu Scheineffekten und zu verzerrten Schätzungen der nichtlinearen Effekte kommen. Ein Teststärkeverlust tritt immer ein. Als zweites wird gezeigt, dass die am stärksten vertretene Ansatzklasse zur simultanen Schätzung von Interaktionseffekten und quadratischen Effekten, nämlich die Klasse der Produkt-Indikator-Ansätze, seit ihrer Erstpublikation durch Kenny und Judd (1984) Spezifikationsfehler aufweist, welche in ähnlicher Form auch in jüngeren Publikationen enthalten sind (z.B. bei Lee, Song & Poon, 2004). Spezifikationsfehler machen die ganze Ansatzklasse für Multikollinearität „anfällig“, so dass es theoretisch zu verzerrten Schätzungen oder Scheineffekten kommen muss. Es wird gezeigt, wie man die Spezifikationsfehler korrigieren kann, d.h. wie man die bestehenden Ansätze erweitern muss. Da die latente Prädiktorkorrelation Bestandteil der Spezifikationsfehler ist, stellt sich die Frage, wie groß die Verzerrungen sind, die sich bei der Anwendung der (unkorrigierten) Produkt-Indikator-Ansätze ergeben, wenn die Multikollinearität steigt. Um diese Frage zu beantworten, wird eine Simulationsstudie durchgeführt. Sie zeigt, dass der Zwei-Stufen-Ansatz von Ping (1996) verzerrte Schätzungen der nicht-linearen Effekte produziert. Dieser Ansatz ist ein Vertreter der Produkt-Indikator-Ansätze und enthält die besagten Spezifikationsfehler. In der Simulationsstudie wird außerdem gezeigt, dass die korrekte Erweiterung des Ansatzes von Jöreskog und Yang (1996) zu erwartungstreuen Schätzungen führt. Als drittes wird der Frage nachgegangen werden, welche theoretischen und empirischen Unterschiede zwischen den neuen verteilungsanalytischen Ansätzen LMS (Klein & Moosbrugger, 2000) und QML (Klein & Muthén, 2007), einerseits, und den klassischen Produkt-Indikator-Ansätzen, andererseits, zu erwarten sind. Dazu werden die theoretischen Eigenschaften der verteilungsanalytischen Verfahren, LMS und QML, untereinander und mit der Klasse der Produkt-Indikator-Ansätze verglichen. Ihre theoretischen Eigenschaften werden beim Vorliegen von Multikollinearität betrachtet. Illustriert werden die theoretischen Unterschiede anhand einer Simulationsstudie, die die Ansätze hinsichtlich ihrer Schätzeigenschaften bei steigender Multikollinearität miteinander vergleicht. In der Simulationsstudie werden die theoretisch herausgearbeiteten Vorteile der verteilungsanalytischen Verfahren, LMS und QML, bestätigt. In der Zusammenschau der theoretischen Überlegungen und der Ergebnisse aus den Simulationsstudien zeigt sich, dass Multikollinearität für alle Ansätze zur simultanen Schätzung multipler nicht-linearer Effekte eine Herausforderung ist. Die forschungspraktische und inhaltliche Relevanz des Multikollinearitätsproblems wird anhand eines Beispiels veranschaulicht. Für in jüngster Zeit diskutierte komplexere Modelle (z.B. moderierte Mediatormodelle) wird Multikollinearität ein Kernproblem sein, dem sich alle Ansätze werden stellen müssen oder für das neue Ansätze entwickelt werden müssen.