Delayed differentiation of epidermal cells walls can underlie pedomorphosis in plants: the case of pedomorphic petals in the hummingbird-pollinated Caiophora hibiscifolia (Loasaceae, subfam. Loasoideae) species

Background Understanding the relationship between macroevolutionary diversity and variation in organism development is an important goal of evolutionary biology. Variation in the morphology of several plant and animal lineages is attributed to pedomorphosis, a case of heterochrony, where an ancestral juvenile shape is retained in an adult descendant. Pedomorphosis facilitated morphological adaptation in different plant lineages, but its cellular and molecular basis needs further exploration. Plant development differs from animal development in that cells are enclosed by cell walls and do not migrate. Moreover, in many plant lineages, the differentiated epidermis of leaves, and leaf-derived structures, such as petals, limits organ growth. We, therefore, proposed that pedomorphosis in leaves, and in leaf-derived structures, results from delayed differentiation of epidermal cells with respect to reproductive maturity. This idea was explored for petal evolution, given the importance of corolla morphology for angiosperm reproductive success. Results By comparing cell morphology and transcriptional profiles between 5 mm flower buds and mature flowers of an entomophile and an ornitophile Loasoideae species (a lineage that experienced transitions from bee- to hummingbird-pollination), we show that evolution of pedomorphic petals of the ornithophile species likely involved delayed differentiation of epidermal cells with respect to flower maturity. We also found that developmental mechanisms other than pedomorphosis might have contributed to evolution of corolla morphology. Conclusions Our results highlight a need for considering alternatives to the flower-centric perspective when studying the origin of variation in flower morphology, as this can be generated by developmental processes that are also shared with leaves. Graphical Abstract

Biogeographical variation on craniomandibular morphology in pallas’s squirrel \(\textit{Callosciurus erythraeus}\) (Pallas, 1779) (Rodentia: Sciuridae) in Vietnam

Different forest vegetations provide herbivorous small mammals with different resources, forcing adaptation since food habits depend on available resources. We expect differences in vegetation to be reflected in the size and shape of the skull and mandible as a result of potentially different feeding resources. Therefore, we analyzed the craniomandibular characteristics of Pallas’s squirrel (Callosciurus erythraeus) in Vietnam. This species commonly occurs in different vegetations in Vietnam, making it a good model for examining morphological adaptation to vegetation type. We analyzed morphologically the skulls and mandibles of 156 specimens collected from 31 localities in Vietnam from 1960 to the present. Principal component analysis showed that females occurring in the tropical lowland evergreen rain forest were clearly separated from those in other vegetations.

Morphological Adaptation of Cave-Dwelling Ground Beetles in China Revealed by Geometric Morphometry (Coleoptera, Carabidae, Trechini)

Cave-dwelling ground beetles in China represent the most impressive specific diversity and morphological adaptations of the cavernicolous ground beetles in the world, but they have not been systematically examined in quantitative terms. The present study focuses on the application of geometric morphological methods to address the morphological adaptations of the tribe Trechini, the most representative group in China. We have employed a geometric morphometry analysis of the head, pronotum, and elytra of 53 genera of Trechini, including 132 hypogean and 8 epigean species. Our results showed that the overall morphological variation of cave carabids has gradually specialized from an anophthalmic to semi-aphaenopsian to aphaenopsian type. There were extremely significant differences (p < 0.01) among four different adaptive types including aphaenopsian, semi-aphaenopsian, anophthalmic, and surface-dwelling Trechini when their adaptability to a cave environment was used as the basis for grouping. Furthermore, there were differences in the phenotypic tree of the head, pronotum, and elytra, and an integrated morphology. To the best of our knowledge, this is the first report on the analysis of the head, pronotum, and elytra of four different adaptive types of ground beetles in order to clarify the morphological adaptations of cavernicolous carabids to the cave environment.

ABSTRACT DEVERBAL FORMATIONS WITH BASES OF GREEK ORIGIN

The object of analysis here are the deverbal abstract nouns with roots of Greek origin and Bulgarian suffix. Most of them are motivated by fully adapted verbs borrowed from Greek and of particular interest from the perspective of word formation are the secondary derivatives formed from denominative verbs motivated by Greek nous and adjectives. The transformation of borrowed words into productive bases, which are combined with local word-forming suffixes, is the final stage of the complex process of lexical borrowing, which follows the stage of morphological adaptation of borrowed words, i. e. their grouping into a certain lexical-grammatical type. Many of them have formed large groups of derivatives. Being composed of elements of different languages, the new lexemes are hybrid in nature regarding their word-formation and their separation into a special category reflects the new status of the Greek bases of the borrowings. The hybrid formations of this type are the final result of the assimilation of the Greek loan words into the Bulgarian language, which is why they occupy a specific position in the Bulgarian lexical und. The use of some of them is dialect or archaic, but they all contribute to the enrichment of the vocabulary and the ways of expression in Bulgarian.

Online Morphological Adaptation for Tactile Sensing Augmentation

Sensor morphology and structure has the ability to significantly aid and improve tactile sensing capabilities, through mechanisms such as improved sensitivity or morphological computation. However, different tactile tasks require different morphologies posing a challenge as to how to best design sensors, and also how to enable sensor morphology to be varied. We introduce a jamming filter which, when placed over a tactile sensor, allows the filter to be shaped and molded online, thus varying the sensor structure. We demonstrate how this is beneficial for sensory tasks analyzing how the change in sensor structure varies the information that is gained using the sensor. Moreover, we show that appropriate morphology can significantly influence discrimination, and observe how the selection of an appropriate filter can increase the object classification accuracy when using standard classifiers by up to 28%.

Developmental influence on evolutionary rates and the origin of placental mammal tooth complexity

Development has often been viewed as a constraining force on morphological adaptation, but its precise influence, especially on evolutionary rates, is poorly understood. Placental mammals provide a classic example of adaptive radiation, but the debate around rate and drivers of early placental evolution remains contentious. A hallmark of early dental evolution in many placental lineages was a transition from a triangular upper molar to a more complex upper molar with a rectangular cusp pattern better specialized for crushing. To examine how development influenced this transition, we simulated dental evolution on “landscapes” built from different parameters of a computational model of tooth morphogenesis. Among the parameters examined, we find that increases in the number of enamel knots, the developmental precursors of the tooth cusps, were primarily influenced by increased self-regulation of the molecular activator (activation), whereas the pattern of knots resulted from changes in both activation and biases in tooth bud growth. In simulations, increased activation facilitated accelerated evolutionary increases in knot number, creating a lateral knot arrangement that evolved at least ten times on placental upper molars. Relatively small increases in activation, superimposed on an ancestral tritubercular molar growth pattern, could recreate key changes leading to a rectangular upper molar cusp pattern. Tinkering with tooth bud geometry varied the way cusps initiated along the posterolingual molar margin, suggesting that small spatial variations in ancestral molar growth may have influenced how placental lineages acquired a hypocone cusp. We suggest that development could have enabled relatively fast higher-level divergence of the placental molar dentition.

Morphology, morphometrics, and molecular characteristics of Apis cerana and Apis nigrocincta from Central Sulawesi, Indonesia

Systematics of honey bees has developed rapidly. Several studies have attempted to infer the kinship between each group of honey bees. One approach is the use identification and phylogenetic analysis using combination of morphology, morphometric, and molecular characteristics data. There are three species of honey bees found in the Central Sulawesi, namely Apis dorsata, A. cerana and A. nigrocincta. The last two species mentioned have similar biological properties, so they present some difficulties to identify especially with morphological characters only. The results showed that the two Apis bee species analyzed in this study, had similar morphological features compared to specimens of the same species from the other regions, whereas the morphometry of the two had variations in size compared to the same species that have been reported in other regions. The variations in the size or morphometric character of worker bees, both those with a larger or smaller size, possibly being a form of morphological adaptation to different environmental conditions. The CO1 and 16S Mitochondrial DNA sequencesof A. cerana and A. nigrocincta from this studywere similarto thesequences of the same species in the GeneBank’s database. This study provide preliminary data contributing to the preservation and utilization of one of Indonesia’s important biodiversity resources.

Arabidopsis CCoAOMT1 Plays a Role in Drought Stress Response via ROS- and ABA-Dependent Manners

Plants possess adaptive reprogramed modules to prolonged environmental stresses, including adjustment of metabolism and gene expression for physiological and morphological adaptation. CCoAOMT1 encodes a caffeoyl CoA O-methyltransferase and is known to play an important role in adaptation of Arabidopsis plants to prolonged saline stress. In this study, we showed that the CCoAOMT1 gene plays a role in drought stress response. Transcript of CCoAOMT1 was induced by salt, dehydration (drought), and methyl viologen (MV), and loss of function mutants of CCoAOMT1, ccoaomt1-1, and ccoaomt1-2 exhibit hypersensitive phenotypes to drought and MV stresses. The ccoaomt1 mutants accumulated higher level of H2O2 in the leaves and expressed lower levels of drought-responsive genes including RD29B, RD20, RD29A, and ERD1, as well as ABA3 3 and NCED3 encoding ABA biosynthesis enzymes during drought stress compared to wild-type plants. A seed germination assay of ccoaomt1 mutants in the presence of ABA also revealed that CCoAOMT1 functions in ABA response. Our data suggests that CCoAOMT1 plays a positive role in response to drought stress response by regulating H2O2 accumulation and ABA signaling.

Evidence of morphological adaptation to life underwater: Sternal keel affects swimming speed in giant water scavenger beetles (Coleoptera: Hydrophilidae: Hydrophilini)

Fundamentally, insects evolved on land and secondarily inhabited aquatic environments multiple times. To live underwater, aquatic insects have acquired enormously variable morphological, developmental, physiological, and ecological traits, such as gas exchange systems and swimming-related characteristics. Giant water scavenger beetles of the tribe Hydrophilini (Coleoptera: Hydrophilidae) are characterized by the presence of sternal keel, which often extends posteriorly. Despite being a conspicuous morphological trait, its function remains unclear. Here, I verified two hypotheses: keel affects (1) submergence time following air replacement as well as (2) speed and oscillatory movement during forward swimming in Hydrophilus acuminatus Motschulsky, 1854. Submergence time was affected by body mass rather than keel removal; in other words, larger individuals replaced their gas gills more frequently. Keel removal reduced swimming speed by 12.5%. These observations support hypothesis (2) and are also consistent with previous speculations that sternal keel is a key adaptation to swim, but the results showed that the degree of oscillation was closely related to body mass but not keel removal. Further studies are warranted to elucidate precise factors through which the presence of keel increases swimming speed. Such studies would provide clues into understanding the associations amongst body size, swimming methods, and morphological traits.