The Science of Nature最新文献

Marine isopod fossils represent a small component of the crustacean fossil record, contrasting the exceptional modern diversity of marine representatives of Isopoda. Examination of previously documented isopod species therefore presents an opportunity to derive additional paleobiological and taphonomic insight of these rare fossils. Here we consider two clusters of Archaeoniscus brodiei from the Lower Cretaceous (middle to upper Berriasian) Intermarine Member of the Durlston Formation, England. The individuals within the clusters are mostly complete, of similar size ranges, and are preserved on two different bedding planes. After examining these individuals, we illustrate, for the first time, appendages and eyes of A. brodiei. The appendage morphology supports the interpretation of A. brodiei as an isopod adapted to a benthic lifestyle. We propose that isopods from the Durlston Formation follow similar taphonomic pathways to arthropods preserved within plattenkalk-like deposits, resulting in enrichment in calcium carbonate and phosphate. Finally, the clusters reflect gregarious activities that were preserved during hypoxic events brought on by concurrent decay of algal blooms.

In this paper, the pollen morphology characteristics, chromosome karyotype characteristics, floral pigments, and scents components of 15 species and hybrids of Syringa L. were obtained by means of scanning electron microscopy, root tips quash method, HPLC–MS, and GC–MS, and the 15 species and hybrids of Syringa L. were clustered separately with each index. Results show that the 15 species and hybrids of Syringa L. are clustered into four different groups separately by each index. In morphological taxonomy, S. microphylla Diels and S. microphylla ‘ShuangJi’, which belong to the Ser. Pubescentes family, original and hybrid species, most varieties of Ser. Syraega are basically cluster into the same group, which is consistent with morphological taxonomy. The findings indicate that the aforementioned four indicators are significantly related to the morphological classification of Syringa L. Among them, the clustering results of pollen morphology were the most consistent with morphological classification. The relationship between the above four aspects and the morphological classification of Syringa L. groups has not been reported in previous related researches, especially indicating the relationship between microscopic morphological indicators, specific physiological components and Syringa morphological classification. The research results have novelty, scientificity and comprehensiveness.

Four main classes of introns (group I, group II, spliceosomal, and archaeal) have been reported for all major types of RNA from nuclei and organelles of a wide range of taxa. When and how introns inserted within the genic regions of genomes, however, is often unclear. Introns were examined from Archaea, Bacteria, and Eukarya. Up to 80 bp surrounding each of the 5' and 3' intron/exon borders were compared to search for direct repeats (DRs). For each of the 213 introns examined, DNA sequence analysis revealed DRs at or near the intron/exon borders, ranging from 4 to 30 bp in length, with a mean of 11.4 bp. More than 80% of the repeats were within 10 bp of the intron/exon borders. The numbers of DRs 6–30 bp in length were greater than expected by chance. When a DNA segment moves into a new genomic location, the insertion involves a double-strand DNA break that must be repaired to maintain genome stability and often results in a pair of DRs that now flank the insert. This insertion process applies to both mobile genetic elements (MGEs), such as transposons, and to introns as reported here. The DNA break at the insertion site may be caused by transposon-like events or recombination. Thus, introns and transposons appear to be members of a group of parasitic MGEs that secondarily may benefit their host cell and have expanded greatly in eukaryotes from their prokaryotic ancestors.

Many butterfly species are conspicuous flower visitors. However, understanding their flower visitation patterns in natural habitats remains challenging due to the difficulty of tracking individual butterflies. Therefore, we aimed at establishing a protocol to solve the problem using the Common five-ring butterfly, Ypthima argus (Nymphalidae: Satyrinae). Focusing on the pollen grains attached the butterfly’s body surface, we examined validities of two pollen analyses based on pollen morphology and DNA markers (ITS1 and ITS2), in addition to the classical route census method. We captured thirty-nine butterflies from mid-April to early July and collected pollen grains from each individual. Morphological and DNA analyses of collected pollens identified eighteen and thirty-four taxa of insect pollinated plants respectively, including woody plants such as Castanopsis. The DNA analysis detected as many as thirteen plant taxa from a single butterfly, indicating its high sensitivity for detecting flower visitation. We detected more plant taxa in May when many individuals were flying. This is assumingly related to the post emergence days of the butterflies with more foraging experience. We also found that fluctuations of pollen grain numbers of Leucanthemum vulgare and Erigeron philadelphicus on individual butterflies depend on their flowering periods overlapping partly. Consequently, we conclude that pollen morphology and DNA barcoding analysis, and field observations are mutually complementary techniques, providing an integrated pollen analysis method to study the pollination ecology of butterflies.

While most dentate non-mammalian vertebrates possess simple conical teeth, some demonstrate complex tooth shapes. Lake Malawi cichlid fishes are an extreme example of this, exhibiting a myriad of tooth shapes driven by an ecologically derived rapid evolution of closely related but distinct species. Tooth shape in mammals is generally considered to be established by signaling centers called primary and secondary enamel knots, which are not believed to be present in non-mammalian vertebrates. In this study, signaling centers of gene expression with epithelial folding with similar molecular patterns to that of mammalian enamel knots are identified, and differences of asymmetric gene expression are identified between fish that possess species specific polymorphisms of either bicuspid or tricuspid teeth. Gene expression is then manipulated indirectly using a small molecule inhibitor of the Notch pathway, resulting in phenotypical aberrations of tooth shape and patterning, including a mimic of a tricuspid tooth in a fish with a naturally occurring bicuspid dentition. This study provides insight into the evolutionary origins of tooth shape and advances our knowledge of the molecular determinants of dental morphology with translational utility in regenerative dentistry.

Information on the age of vertebrate species such as sea turtles is crucial for planning management and conservation actions. The age of sea turtles has been estimated by skeletochronological analysis using skeletal growth marks in different bones. This study focused on the consistency of the number of visible lines of arrested growth (LAG) observed from the humerus and phalanx bone used for age estimation in Chelonia mydas and Caretta caretta. We collected 67 humeri and phalanges of C. mydas (n = 47) and C. caretta (n = 20) from Samandağ beach, eastern Mediterranean in 2020–2022. LAG in the humerus and phalanx of the same individual were counted by two readers, and their consistency with each other was determined by percent agreement (PA), average percent error (APE), and coefficient of variation (CV). The significance of the difference between them was determined by the McNemar test. The mean number of visible LAG counted from the humerus is greater than the mean number of visible LAG counted from the phalanx, i.e., the humerus contains more growth marks than the phalanx. However, in individuals up to 15 LAG in C. mydas and 10 LAG in C. caretta, the mean number of visible LAG observed in both bone tissues is compatible. This was supported by the differences in the resorption rates calculated in both bones, indicating that the number of LAG lost due to resorption may also differ between these two bone types. It is recommended that the back calculation and/or correction factor applied for the humerus be avoided for the phalanx.

Polarization is a property of light that describes the oscillation of the electric field vector. Polarized light can be detected by many invertebrate animals, and this visual channel is widely used in nature. Insects rely on light polarization for various purposes, such as water detection, improving contrast, breaking camouflage, navigation, and signaling during mating. Dragonflies and damselflies (Odonata) are highly visual insects with polarization sensitivity for water detection and likely also navigation. Thus, odonates can serve as ideal models for investigating the ecology and evolution of polarized light perception. We provide an overview of the current state of knowledge concerning polarized light sensitivity in these insects. Specifically, we review recent findings related to the ecological, morphological, and physiological causes that enable these insects to perceive polarized light and discuss the optical properties responsible for the reflection of polarized light by their bodies and wings. Finally, we identify gaps in the current research and suggest future directions that can help to further advance our knowledge of polarization sensitivity in odonates.

Fingerprints hold a crucial position in forensic science, primarily for identification purposes, with thumbprints emerging as the most frequently recovered evidence at crime scenes. The main purpose of the present study was to conduct a comparative analysis of thumbprints of siblings and non-sibling pairs to investigate resemblance and similarities in fingerprint patterns. Thumbprints of 144 individuals (72 siblings and 72 non-siblings) from 36 families were obtained. Jaccard Similarity Index was employed to analyse the similarity between the fingerprint patterns of siblings and non-siblings. The strength of association between the variables is evaluated by chi-square and Cramer’s V tests. The results indicated a significant similarity (69.44%) in thumbprint patterns among sibling pairs, demonstrating congruence in their right thumbprints, while non-sibling pairs exhibited a mere 30.56% similarity in the right thumbprints. Statistical analyses revealed a significant association (p = 0.0002) between sibling pairs, indicating a strong correlation in right-hand thumbprint patterns. The study bears substantial implications across various fields, including anthropology, population genetics, medical genetics and forensic science. Moreover, it may facilitate the examination of population similarities and variations and may aid in enhancing forensic investigations by identifying familial resemblance and similarity.

The seagrass ecosystem supports a diverse range of marine life, including fish, crabs, and seahorses. It plays a vital role in providing essential services such as habitat creation, nutrient cycling, and shoreline stabilization. In the present study, we conducted line intercept transects to assess the abundance of Pinna shells in seagrass meadows of the Sangumal region in the Palk Bay, India. Among the 30 transects surveyed, we observed a total of 33 Pinna shells. Ten shells were found to be empty, while 6 hosted blenny fish. The fish were identified as saber-tooth blenny Petroscirtes variabilis Cantor, 1849, via integrative taxonomy (morphology + cytochrome oxidase subunit I gene phylogeny). The phylogenetic tree based on the maximum likelihood inference method indicated that P. variabilis clustered together with other sequences of P. variabilis available in the NCBI GenBank. We also revealed the importance of empty Pinna shells acting as refugia for blenny fish, which was evident from the presence of eggs attached to the shells.

This paper analyzes the paleoneurology (cranial endocast and maxillary canal) of Massetognathus pascuali, an iconic non-mammaliaform cynodont from the early Late Triassic of South America, using Neutron Tomography. The application of neutron tomography holds the potential for uncovering more refined anatomical and quantitative data. The newly examined cranial endocast shows a forebrain with a tubular shape without an interhemispheric fissure, presence of a pineal body (with a closed parietal foramen), and a marked unossified zone. In comparison with a smaller, putatively juvenile specimen previously studied (PVL 4016), the new endocast exhibits a similar degree of encephalization, indicating little change in relative brain size between both ontogenetic stages. In the context of cynognathian brain evolution, M. pascuali maintained a low encephalization quotient, typical of early cynognathians, contrasting with the higher values of some Late Triassic taxa. The maxillary canal of M. pascuali is described here for the first time. It is considerably ramified, although slightly less than in some early cynognathians, following the general pattern of non-probainognathians and suggesting the absence of a flexible rhinarium or mobile vibrissae. By integrating endocast data with the maxillary canal, this study offers enhanced insights into the neurosensory ecology of M. pascuali, thereby deepening our understanding of its biology and ecological interactions.

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