The male genital, pregenital skeleton, musculature of male terminalia, and the ovipositor were studied in Synthesiomyia nudiseta (Wulp). A comparison was conducted between the terminal segments and muscles of S. nudiseta and previously studied species of the subfamily Azeliinae. Notable differences were found between previously studied species of the subfamily Azeliinae and Synthesiomyia + Muscina. These differences correspond to apomorphic character states in Synthesiomyia + Muscina, including the large size of the ejaculatory apodeme and the powerful constrictors of the ejaculatory apodeme M 23; the completely membranous sternite VI; the membrane connection of the muscle ISM 5 (lower); the small size of pregonites and postgonites; and the joints of the phallapodeme muscles М 21 at the base of the hypandrial arms. Based on these differences, Synthesiomyia + Muscina can be assigned to the subfamily Reinwardtiinae, as has been confirmed by recent molecular studies. However, similarities in the set of pregenital muscles and the set of phallapodeme muscles between Synthesiomyia + Muscina and the Azeliinae were also noted. These similarities may be considered as plesiomorphic character states, indicating their phylogenetic relationship. It can be argued that Reinwardtiinae + Azeliinae constitute sister groups and occupy the basal position within the family Muscidae.
Hymenoepimecis wasps (Hymenoptera: Ichneumonidae) are ectoparasitoids of spiders that modify the hosts’ behaviour by inducing changes in webs. Variations in the male reproductive tract contribute to enhancing our understanding of the reproductive behaviour of these insects. This study describes the morphology of the male reproductive tract of Hymenoepimecis bicolor (Brullé, 1846) using light microscope. The male reproductive tract of H. bicolor consists of a pair of testes, each containing a single follicle, two vasa deferentia, one ejaculatory duct and two accessory glands. The testis follicle has cysts at various stages of spermatogenesis, indicating ongoing sperm cell development and maturation. The vasa deferentia are elongated, with a coiled distal portion, whereas the proximal regions are laterally associated with a pair of accessory glands. The wall of the vasa deferentia has simple cuboidal epithelium. The accessory glands had a simple columnar epithelium with the lumen filled with heterogeneous content. The seminal vesicle is absent. The similarity in the anatomy and histology of the male reproductive tract of H. bicolor with other Hymenoptera suggests that the parasitoid behaviour does not result in significant alteration to their reproductive organs, indicating that the reproductive tract is conserved in Hymenoptera, regardless of their behaviours.
The skin of snakes acts as the first interface between these reptiles and the environment they live in. It plays an important role in the ecology of these organisms, and specialised structures, such as tactile corpuscles, are crucial in the sensing of a wide variety of stimuli. This study, by examining the presence, localisation and colocalisation of serotonin, substance P, PGP 9.5 and tubulin, wants to demonstrate the sensory role that these structures play in the ecology of the Green whip snake Hierophis viridiflavus (Lacépède, 1789). This study presents the first evaluation of nerve and immune molecules (TLR2) in the tactile corpuscles of H. viridiflavius ventral skin, indicating a potential defence role of these structures. These findings provide valuable information on the ecology of snakes, their defence systems, and their evolutionary morphostructural adaptations. Additionally, the identification of these corpuscles could provide valuable support for taxonomic recognition. Furthermore, this study expands the knowledge about stimuli sensing in snakes.
Regeneration varies largely among metazoans. Aside molecular processes, this epiphenomenon depends on the biological complexity and evolutive history of each species during the adaptation to their specific environment. While most species adapted to marine or freshwater conditions can extensively regenerate, those adapted to terrestrial conditions and parasitism lost the ability to regenerate. They are mainly represented from ascelmintes evolving eutely and numerous arthropods and amniotes. High regeneration can only occur in water-adapted species and requires high tissue hydration, indirect development through metamorphosis and often also presence of asexual propagation. Metamorphosis allows the anatomical-physiological transformation of a larva in an adult through an initial destructive phase followed by a constructive (regenerative) phase. Invertebrates and vertebrates that possess genomes including metamorphic genes can re-utilize in part or largely similar genes for the regeneration of lost organs. I submit that during land adaptation in both invertebrates and vertebrates the initial larval stages and metamorphosis were lost or altered as some key genes, including those for telomerases, could no longer be expressed in the dry environment. Consequently, also the initial regenerative ability was lost while other epiphenomena were gained, including complex immunity and behaviour but also an evident process of ageing.
Skin structure of the slow worm lizard Anguis fragilis (Anguidae, Sauria, Reptilia) with emphasis on the epidermal micro-ornamentation in relation to the animal movements (Acta Zoologica, Stockholm). The structure of the skin and superficial micro-ornamentation in the slow worm Anguis fragilis, a limbless lizard with a fossorial activity, was examined using histology, immunofluorescence, scanning and transmission electron microscopy. The scales, with a triangular to trapezoidal shape, are very overlapped and interlocked to form a smooth surface and are reinforced by osteoderms. The epidermis shows a thin Oberhautchen layer merged with a thicker beta-layer that contains corneous beta-proteins. The SEM survey detects a smooth surface made of tile-like patterned Oberhautchen cells with irregular perimeters that form an interlocking surface. Disk-like sensory organs of 15–20 μm diameter are observed only on the head scales, the first to sense the environment and contact the ground. Numerous Oberhautchen denticles, namely corneous thorns of about 0.2–0.3 μm, adorn the caudally directed perimeter of Oberhautchen cells in the ventral scales of the trunk and tail. This microstructure may determine gripping and increased friction with the substrate during the lateral undulating and forward movements of the slow worm. TEM observations reveal sparse short serrated protrusions of Oberhautchen cells that are largely merged with the underlying beta-cells. Altogether, the scale surface of the slow worm efficiently suites this limbless lizard to its environment and lifestyle.
Shrimp fisheries and culture are important food sources worldwide. Central East Pacific fisheries are mainly supported by four species: Penaeus brevirostris, P. californiensis, P. stylirostris and P. vannamei. However, the same shrimp fishery practices, management strategies and closures are applied to these four species despite their differences in life history and reproductive periods. Most molecular studies have focused on the cultured species P. vannamei, while knowledge for the rest of the species is scarce. Therefore, this study sought to examine the transcriptomes of these four shrimp species from the Mexican Pacific at different maturity stages. A total of 165 unigenes were found to be reproduction-related in the four shrimp species. The genes with the highest overall expression levels were associated with ribosomes, transcription and methyltransferase pathways. Moreover, the reproduction-related genes with the highest expression values were polehole protein and ovarian peritrophin. The major expression similarities were primarily among pre-vitellogenic and vitellogenic females within each species, and secondly among the species P. brevirostris and P. californiensis and the species P. vannamei and P. stylirostris. Although these four species might share a geographical location or niche, the expression of reproduction related-genes at different gonadal maturity stages exhibited species-specific variations.
Fertilized bird eggs are an alternative model to conventional animal testing. In recent studies, a preclinical imaging model based on large ostrich eggs was introduced in a clinical research centre using imaging systems designed for humans, thus bypassing the need for dedicated small animal imaging systems. Ostrich eggs are only laid during the season with increased daylength, which limits its year-round availability. The current study focuses on large emu eggs instead of ostrich eggs and aims at investigating its suitability for preclinical imaging research. Physiological development of emu embryos was observed by serial weightings and serial CT scans until developmental day (DD) 46. Differences between fertilized a non-fertilized eggs were analysed. In fertilized eggs, the embryo was identified on CT scans as early as DD 13. As expected, CT scans showed continuous embryonal development and growth over time, comparable to ostriches. Neither the eggs' volume and weight nor the weight loss nor the radiodensity provided significant differences between fertilized and non-fertilized eggs. Despite inferior incubation success in emus compared to ostriches, suitability of emu eggs for artificial incubation and subsequent research was confirmed. Hence, emu eggs represent an alternative model for preclinical imaging and allow a year-round use for research purposes if combined with ostrich eggs.
In this ecomorphological study, we investigate how the ventral pectoral girdle morphology of anurans correlates with their locomotor modes, habitat preferences, and phylogenetic relationships. We analysed 18 morphometric variables of the pectoral girdle's ventral region across 19 anuran species, encompassing diverse locomotion modes (jumping, hopping, walking, and swimming) and habitats (arboreal, bushy, terrestrial, and aquatic). Our findings, predominantly explained by the Ornstein–Uhlenbeck model, reveal evolutionary adaptations in pectoral girdle morphology driven by habitat-specific demands. Notably, bushy and walker-jumper species exhibit large clavicles, coracoids, and sternums, along with a broad medial pectoral girdle and bigger epicoracoid. Terrestrial and arboreal- jumpers have a larger omosternum area compared to predominantly swimming species. Arboreal walkers show shorter epicoracoid horns and narrower coracoids. Interestingly, bushy and terrestrial species have a higher proportion of bone tissue in their pectoral girdles. This indicates a potential adaptation to support the additional to adaptation to participate in shock absorption. The patterns recovered underscore the intricate relationship between anatomical evolution and environmental adaptation in anurans.