{"title":"Cuticle ultrastructure of the Early Devonian trigonotarbid arachnid Palaeocharinus","authors":"","doi":"10.1016/j.asd.2024.101392","DOIUrl":"10.1016/j.asd.2024.101392","url":null,"abstract":"<div><div>The cuticle is a key evolutionary innovation that played a crucial role in arthropod terrestrialization. Extensive research has elucidated the chemical and structural composition of the cuticle in extant arthropods, while fossil studies have further informed our understanding of cuticle evolution. This study examines the three-dimensionally preserved cuticular structure of the Early Devonian trigonotarbid arachnid genus <em>Palaeocharinus</em>, from the Rhynie chert of Scotland (∼408 Ma). Trigonotarbids, an extinct group of tetrapulmonate arachnids, are among the earliest known unequivocally terrestrial arthropods, and thus may shed light on the evolution of terrestriality. Using high-resolution Confocal Laser Scanning Microscopy (CLSM), we reveal detailed morphological features at the nanometre level. The external cuticle surface of <em>Palaeocharinus</em> is characterized by polygonal scales, sensilla, and small pores identified as the openings of dermal glands and wax canals. Internally, the cuticle exhibits polygonal clusters of pore canals, through which wax was transported from the epidermis to the cuticular surface. The pore canals twist along their vertical axes, reflecting the \"twisted plywood\" or Bouligand arrangement of chitin-protein microfibril planes characteristic of modern arthropod cuticles. Overall, the cuticle of <em>Palaeocharinus</em> is characteristically thick relative to those of other extinct and extant chelicerates, such thickening being a possible adaptation to terrestrial life.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142481639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The eyestalk photophore of Northern krill Meganyctiphanes norvegica (M. Sars) (Euphausiacea) re-investigated: Innervation by specialized ommatidia of the compound eye","authors":"","doi":"10.1016/j.asd.2024.101393","DOIUrl":"10.1016/j.asd.2024.101393","url":null,"abstract":"<div><div>Members of the Euphausiacea (“krill”) generate bioluminescence using light organs, the so-called photophores, including one pair associated with the eyestalks, two pairs on the thoracic segments, and four unpaired photophores on the pleon. The photophores generate light <em>via</em> a luciferin–luciferase type of biochemical reaction in light-emitting cells comprised in a photophore compartment called “lantern”. The behavioral significance of bioluminescence in krill is discussed controversially, and possible functions include a defensive function, camouflage by counter-shading, and intra-specific communication. Light production of all krill photophores is controlled by hormonal and neuronal pathways but our knowledge about the nature of these pathways is still rudimentary. Here, we provide a detailed description of the eyestalk photophore's histology in Northern krill <em>Meganyctiphanes norvegica</em>, and used immunohistochemistry combined with confocal laser-scan microscopy to explore this organ's serotonergic innervation. Furthermore, we provide evidence that the photophore is innervated by a distinct photophore nerve that originates from a specialized cluster of ca. 30 highly modified ommatidia at the dorsal rim of the compound eye that are optically isolated from the other ommatidia. Our findings suggest the compound eye – photophore link as a major anatomical axis to adjust the photophore activity.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142481642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evolution of and structures involved in wing folding in featherwing beetles (Coleoptera: Ptiliidae)","authors":"","doi":"10.1016/j.asd.2024.101394","DOIUrl":"10.1016/j.asd.2024.101394","url":null,"abstract":"<div><div>The ability to fold the wings is an important phenomenon in insect evolution and a feature that attracts the attention of engineers who develop biomimetic technologies. Beetles of the family Ptiliidae (featherwing beetles) are unique among microinsects in their ability to fold their bristled wings under the elytra and unfold them before flight. The folding and unfolding of bristled wings and of the structures involved in these processes varies among ptiliids, but only one species, <em>Acrotrichis sericans,</em> has been analyzed in detail<em>.</em> In this study, we analyze in detail the wing folding pattern and the mechanism of the folding and unfolding of the wings in species of different lineages of Ptiliidae, using scanning electron, сonfocal laser scanning, and optical microscopy, and compare the wing-folding patterns of Ptiliidae with those of the sister group, Hydraenidae, to reconstruct the evolution of the involved structures. We confirm that the two subfamilies of Ptiliidae have two distinct patterns of wing folding: Nossidiinae has retained the ancestral (‘agyrtid’) asymmetrical pattern with overlapping wings and with folds at different angles to the wing axis, while Ptiliinae, which includes the smallest of all known beetles, has evolved a symmetrical pattern with non-overlapping wings and folds perpendicular to the wing axis, with one additional oblique fold in the genus <em>Ptenidium</em>. Ptiliids have a longer alacrista, which helps to lock the elytra at rest, and a more complex set of structures involved in wing folding on abdominal tergites. These genus-specific structures, which include setae and wing-folding patches on some of the tergites and the palisade fringe of setae on the posterior margin of tergite 7, help the insect to tuck the wing under the elytron and fold it after flight. The symmetrical wing-folding pattern is simpler than the wing folding patterns of most larger beetles. The obtained data on the mechanisms and patterns of the folding and unfolding of the wings in Ptiliidae elucidate the evolution of wing folding as an adaptation protecting the wings at rest. Structures involved in wing folding can be used as distinguishing characters in taxonomy. The wing-folding mechanisms of Ptiliidae may eventually be used for developing miniature biomimetic robots.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142481640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Morphology of lecithotrophic postlarvae of genus Austropallene (Arthropoda: Chelicerata) with some notes on reproductive strategy","authors":"","doi":"10.1016/j.asd.2024.101395","DOIUrl":"10.1016/j.asd.2024.101395","url":null,"abstract":"<div><div>The family Callipallenidae Hilton, 1942 belongs to the superfamily Nymphonoidea Pocock, 1904 together with other family, Nymphonidae. The lecithotrophic postlarvae hatch from the eggs of the callipallenid sea spiders, but the data on this life stage are very scarce and fragmentary. This gives a very limited understanding of larval anatomy, morphology, and diversity. The larvae of <em>Austropallene bucera</em> Pushkin, 1993, <em>Austropallene calmani</em> Gordon, 1944, and <em>Austropallene cristata</em> Bouvier, 1911 have been studied and described for the first time by the methods of light (LM) and scanning electron microscopy (SEM). The main morphometry parameters have been determined in larvae and adult egg-bearing males. The general plan of the postlarvae is presented together with its specific features. The postlarvae of the studied <em>Austropallene</em> species combine the features of lecithotrophic and free-living pycnogonid larvae. The diversity of larvae in the Nymphonoidea superfamily has been analysed considering original and published data, and a morphological series has been developed. The complex of lecithotrophic larvae, like postlarvae of Callipallenidae, should be considered as primary for the entire superfamily. It is also suggested that sea spiders with lecithotrophic larvae tend to follow the K-strategy, but they care for their offspring to varying degrees.</div></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142481641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ultrastructure of the larval rectum of the scorpionfly Panorpa liui (Mecoptera: Panorpidae)","authors":"","doi":"10.1016/j.asd.2024.101383","DOIUrl":"10.1016/j.asd.2024.101383","url":null,"abstract":"<div><p>The rectum is an important part of the alimentary canal responsible for ion and water reabsorption of insects. However, it has rarely been studied in the larvae of Panorpidae, the largest family in Mecoptera. Here, we investigated the ultrastructure of larval rectum of the scorpionfly <em>Panorpa liui</em> Hua, 1997 using light and transmission electron microscopy. The rectum comprises tracheal muscular layers, connective tissue, non-cellular basal lamina, junctional cells, rectal epithelium, cuticle with irregular outlines, and a central lumen. The rectal epithelium is infolded to form six longitudinal rectal folds, which are distinct from rectal pads or papillae. In each rectal fold, the apical and basal plasma membranes of epithelial cells are infolded and the lateral plasma membranes form septate and scalariform junctions. The well-developed rectal folds are postulated to be closely associated with reabsorption of ions and water in the larvae. The associations of rectal folds with larval behaviors are briefly discussed in Mecoptera.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142146959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Morphology and distribution of antennal sensilla in five species of solitary bees (Hymenoptera, Apoidea)","authors":"","doi":"10.1016/j.asd.2024.101382","DOIUrl":"10.1016/j.asd.2024.101382","url":null,"abstract":"<div><p>Solitary bees play a crucial role in ecological systems, contributing to the pollination of crops and wild plants. All females are reproductive, and their habitat requirements include nesting sites, food resources and nesting materials. Although these activities require the ability to detect biotic and abiotic stimuli in the environment, the sensory system of these species is poorly studied. In this study, the antennal sensilla of five solitary bee species belonging to three Apoidea families were investigated using scanning electron microscopy. These included two species of stem-nesting bees, <em>Ceratina cucurbitina</em> (Rossi, 1792) (Apidae) and <em>Osmia scutellaris</em> (Morawitz, 1868) (Megachilidae), and three species of ground-nesting bees, <em>Lasioglossum brevicorne</em> (Schenck, 1870), <em>Lasioglossum leucozonium</em> (Schrank, 1781), and <em>Lasioglossum villosulum</em> (Kirby, 1802) (Halictidae). Thirteen different types of antennal sensilla were identified in females based on their morphological characteristics: sensilla trichodea (subtypes STI, II, III), chaetica (subtypes SchI, II), basiconica (subtypes SBI, II, III, IV), placodea, campaniformia, coeloconica, and ampullacea. Their functional role was discussed and morphology was compared among the species and within the antennal segments in each species. The results provide a baseline for further physiological and behavioural studies to determine the role of antennal sensilla in habitat selection, food search and nesting site selection.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142146958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coevolution of spermatozoa and spermathecae in Lonchopteridae (Diptera)","authors":"","doi":"10.1016/j.asd.2024.101385","DOIUrl":"10.1016/j.asd.2024.101385","url":null,"abstract":"<div><p>Across the species of spear-winged flies (Diptera: Lonchopteridae) there is a remarkable variation in size of the female reproductive tract, especially of the spermathecae. In this family there are two tubular spermathecae, which are divided into four morphologically and histologically distinct sections of different lengths and functions. The dimensions of the spermathecae and their individual sections were examined across 11 <em>Lonchoptera</em> species and related to the dimensions of the respective spermatozoa. 3D reconstructions from serial sectioning made it possible to include the volume in these considerations, which is a new approach in this context. Results show that the spermathecae are always longer than the respective spermatozoa. There is a highly significant positive linear correlation between the length of the spermatozoa and the length of the spermathecae in total as well as some of the individual spermathecal sections, suggesting a coevolution of these characters. Moreover, the volume of the spermathecae is much larger in those species with longer and more voluminous spermatozoa, but the volume increase is not sufficient to keep constant the number of spermatozoa that fit within. The observed patterns are discussed with respect to their functional and evolutionary implications, including a new hypothesis on the possible selective advantage of increased spermatozoon length.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1467803924000550/pdfft?md5=e3e1b66572e0381459443308d38ece77&pid=1-s2.0-S1467803924000550-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genomics investigation of the potentially invasive firefly Photinus signaticollis Blanchard 1845: Complete mitochondrial genome, multigene phylogenies and obtention of the luciferase and luciferin-regenerating genes","authors":"","doi":"10.1016/j.asd.2024.101384","DOIUrl":"10.1016/j.asd.2024.101384","url":null,"abstract":"<div><p>A genomic investigation of the potentially invasive firefly <em>Photinus signaticollis</em> Blanchard1845 has been performed and led to the obtention of its complete 16,411 bp long mitochondrial genome. The mitogenome encodes 13 protein-coding genes, 22 tRNA genes and 2 rRNA genes. With other species of the <em>Photinus</em> complex it shares several premature terminations of some protein-coding genes and also an overlap between <em>cox1</em> and <em>tRNA-Tyr</em>. By data-mining, the complete luciferase and luciferin-regenerating genes were also identified from the contigs file and compared with existing data, in addition to <em>WG</em> and CAD, two genes used in pioneering phylogenetic studies on fireflies. Three maximum likelihood phylogenies were derived from all these data. The multigene phylogeny based on all mitochondrial protein-coding genes strongly associates <em>P. signaticollis</em> with <em>Photinus pyralis</em> Linnaeus, 1758 and the lantern-less daily “winter firefly”, <em>Photinus corruscus</em> Linnaeus, 1767. A second phylogeny based on concatenated sequences of the <em>cox1</em>, <em>WG</em> and <em>CAD</em> genes positions <em>P. signaticollis</em> as a sister clade to a large cluster of species containing the 7 sub-groups previously evidenced among the North American species of the <em>Photinus</em> complex. A third phylogeny based on the amino-acid sequence of the luciferase protein associates <em>P. signaticollis</em> to <em>Photinus scintillans.</em> The analysis presented here will most certainly help to come to a better understanding of the very complex inter-relationships in the very large <em>Photinus</em> genus.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Morphology of the sting apparatus in sapygid wasps of the subfamily Sapyginae (Hymenoptera: Sapygidae)","authors":"","doi":"10.1016/j.asd.2024.101381","DOIUrl":"10.1016/j.asd.2024.101381","url":null,"abstract":"<div><p>Sapygidae is a small family of Aculeata (Hymenoptera), which is divided into two subfamilies Fedtschenkiinae and Sapyginae. The morphology of the skeleton of the sting apparatus in some European species of Sapyginae, which are kleptoparasites of wild bees from the families Megachilidae, Apidae and Colletidae, was examined. Significant differences in its skeletal structure were noted between <em>Sapygina decemguttata</em> and representatives of the genera <em>Sapyga</em> and <em>Monosapyga</em>. The sting of <em>Sapygina</em> belongs to the decurved type, while <em>Sapyga</em> and <em>Monosapyga</em> have a sting close to the coiled type. A comparison of the structure of the skeletons of the sting apparatuses of <em>Sapygina</em> and <em>Sapyga</em> with that of <em>Fedtschenkia</em> (according to other authors) was made. The similarity of the structure of the sting apparatuses of <em>Sapygina</em> and <em>Fedtschenkia</em> was noted. The possibility of using the Sapyginae sting as an ovipositor is discussed.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142047797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The structure of a gilled stonefly larva from the mid-Cretaceous Kachin amber","authors":"","doi":"10.1016/j.asd.2024.101380","DOIUrl":"10.1016/j.asd.2024.101380","url":null,"abstract":"<div><p>Perlidae stands as the most diverse family within Plecoptera, with evidence suggesting possible adaptation to warmer aquatic environments. Tracheal gills are hypothesized to have played a pivotal role in this radiation process. This study presents the description of a fossilized stonefly larva with gills, preserved as a fresh exuvia in mid-Cretaceous Kachin amber from northern Myanmar. The larva was classified within the family Perlidae based on distinctive morphological traits, including toothed lacinia and sharp-cusped mandibles, slender palps, glossae shorter than rounded paraglossae, and highly branched gills on the sides and ventral surface of thoracic segments. Additionally, the presence of a transverse, sparse, and irregular setal row on the occiput further indicates classification within the subfamily Acroneuriinae. Notably, the fossilized larva displays striking similarities in gill morphology and distribution to certain extant members within Perlidae, suggesting that these gill structures have an advantage in various aquatic habitats.</p></div>","PeriodicalId":55461,"journal":{"name":"Arthropod Structure & Development","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}