Adult Morphology Research Articles

Naked cuticle inhibits wingless signaling in Drosophila wing development

Wnt signaling is one of the major signaling pathways that regulate cell differentiation, tissue patterning and stem cell homeostasis and its dysfunction causes many human diseases, such as cancer. It is of tremendous interests to understand how Wnt signaling is regulated in a precise manner both temporally and spatially. Naked cuticle (Nkd) acts as a negative-feedback inhibitor for Wingless (Wg, a fly Wnt) signaling in Drosophila embryonic development. However, the role of Nkd remains controversial in later fly development, particularly on the canonical Wg pathway. In the present study, we show that nkd is essential for wing pattern formation, such that both gain and loss of nkd result in the disruption of Wg target expression in larvae stage and abnormal adult wing morphologies. Furthermore, we demonstrate that a thirty amino acid fragment in Nkd, identified previously in Wharton lab, is critical for the canonical Wg signaling, but is dispensable for Wg/planar cell polarity pathway. Putting aside the pleiotropic nature of nkd function, i.e. its role in the Decapentaplegic signaling, we conclude that Nkd universally inhibits the canonical Wg pathway across a life span of Drosophila development.

Allometric analysis sheds light on the systematics and ontogeny of anurognathid pterosaurs

ABSTRACT Anurognathids are a clade of non-pterodactyloid pterosaurs with generally conservative morphology, but specializations as insectivores. They are represented by a disparate collection of adult and juvenile specimens that range in wingspan from ∼0.24–1 m. There have been concerns about the extent to which ontogenetic variation might affect phylogenetic inference, and indeed how aspects of their ontogeny might relate to the distinctive anurognathid adult morphology. Here we perform allometric analysis on 23 key skeletal dimensions in 13 anurognathid specimens. Our results show that all anurognathids share a common growth trajectory in most dimensions, and that ontogeny affects variation in a minority of characters commonly used in phylogenetic analysis. Excluding these ontogeny-related characters, a new taxon, Cascocauda rong gen. et sp. nov., is established. Based on the ontogenetically corrected dataset, our phylogenetic analysis supports Anurognathidae as the sister-group of Breviquartossa and reveals a general trend of tail reduction in the clade. Allometric growth suggests the anurognathid lifestyle remained consistent throughout ontogeny, maintaining a highly maneuverable flight style by near-isometric development in the wing, small prey (i.e., insects), by strong negative allometry in the skull, and an arboreal habit by strong positive allometry in the claws. This specialized lifestyle suggests retention of plesiomorphic juvenile traits into later ontogeny and facilitated morphological stasis by stabilizing selection during over 40 million years of evolution in the group.

A review of the black species of Cyclocephala Dejean (Coleoptera: Scarabaeidae: Dynastinae) from Colombia.

The black species of the genus Cyclocephala Dejean (Coleoptera: Scarabaeidae: Dynastinae: Cyclocephalini) from Colombia are reviewed. I define species groups based on the morphology of adults, re-describe those species occurring in Colombia, describe two new species (Cyclocephala santandereana new species and Cyclocephala arhuacana new species), list the species reported for Colombia, provide a key to identify groups and the species within each group, and present species distribution and life history data. This review includes the Cyclocephala cribrata species group previously defined with C. boucheri Dechambre, C. carbonaria Arrow, C. cribrata Burmeister, C. dechambrei Dupuis, C. boliviana Dechambre, C. dilatata (Prell), C. ergastuli Dechambre, C. latipennis Arrow, C. marqueti Dechambre, C. proxima Dechambre, C. rogerpauli Moore, Branham, Cave, and C. variolosa Burmeister. The Cyclocephala fasciolata species group contains C. abrelata Ratcliffe Cave, C. brevipennis Endrdi, C. fasciolata Bates, C. melane Bates, and Cyclocephala santandereana new species. The Cyclocephala ligyrina species group has C. arhuacana new species, C. dalensi Ponchel, C. dyscinetoides Dechambre, C. endroedyyoungai Endrdi, C. kaszabi Endrdi, C. ligyrina Bates, Cyclocephala nigerrima Bates, C. rufa Endrdi, and C. scarabaeina (Gyllenhal). Cyclocephala carinatipennis Martnez Morn is proposed as a new junior synonym of C. rufa Endrdi. A larva of the Cyclocephala cribrata species group is described for the first time. An analysis of the characters of the adults and the described larva of the species group is performed to imply phylogenetic implications. New country records of C. dalensi and C. marqueti are recorded for Colombia.

Human orbital muscle in adult cadavers and near-term fetuses: its bony attachments and individual variation identified by immunohistochemistry.

To compare fetal and adult morphologies of the orbital muscle (OM) and to describe the detailed topographical anatomy in adults. Using unilateral orbits from 15 near-term fetuses and 21 elderly cadavers, semiserial horizontal or sagittal paraffin sections were prepared at intervals of 20-100µm. In addition to routine histology, we performed immunohistochemistry for smooth muscle actin. At near term, the OM consistently extended widely from the zygomatic bone or the greater wing of the sphenoid to the maxilla or ethmoid. Thus, it was a large sheet covering the future inferior orbital fissure. In contrast, the adult OM was a thin and small muscle bundle connecting (1) the greater wing of the sphenoid to the maxilla (11/19 cadavers), (2) the lesser wing of the sphenoid to the maxilla (5/19) or the greater wing (3/19). The small OM was likely to be restricted within the greater wing (5/19 cadavers) or the maxilla (3/19). Two of these five types of OM coexisted in eight orbits. OM attachment to the lesser wing was not seen in fetuses, whereas ethmoid attachment was absent in adults. The lesser wing attachment of the OM seemed to establish after birth. A growing common origin of the three recti was likely involved in "stealing" the near-term OM attachment from the ethmoid. The strong immunoreactivity of remnant-like OM in the elderly suggests that OM contraction is still likely to occur against the increased flow through a thin vein. However, the contraction might have no clinical significance.

Assessing how changes in temporal resource quality influence the reproductive performance of the dung beetle Onthophagus binodis

1. Both larval and adult dung beetles depend on dung resources for nutrition. The quality of the dung resources utilised by beetles can influence adult morphology, adult biomass, and life history parameters of dung beetles. Although several studies have compared dung nutrients of different vertebrate dung types, variation in dung nutrients over time has been less studied.2. Here, moisture content and chemical parameters of dung were analysed at monthly intervals over 12 months. The reproductive output of Onthophagus binodis fed dung collected at four different months of the year is also measured to assess the relationship between dung resources and dung beetle performance. The experiments were carried out under controlled conditions: 25 ± 1 °C: 15 ± 1 °C (L: D) and 60 ± 5% RH, respectively, with a photoperiod of 14L:10D.3. Over the 12‐month sampling period, the maximum number of broods and highest brood weight were observed from beetles utilising dung collected in the Austral summer (February 2018). The analysis of dung over the 12‐month period showed that the electrical conductivity and phosphorous, manganese, and magnesium content of dung were highest in February 2018.4. The results suggest that the variation in dung resources, such as moisture and minerals, across the year affected the reproductive performance of Onthophagus binodis, which was highest when beetles were provisioned with summer dung.

Guttulapsyche mayaensis, gen. et sp. nov., a Psychidae from Mexico with unusual larval ethology (Insecta: Lepidoptera: Typhoniinae).

A new genus and species, Guttulapsyche mayaensis gen. et sp. nov., of Psychidae are described from Mexico. The new taxon shares some characters with Arrhenophaninae and several others with Typhoniinae. Together with Antillonatus sessilis Nez Davis, 2016 it is already the second Neotropic species with a complex of characteristics that deviates from the previous understanding of the two subfamilies. The morphology of adults, larva, and pupa is described and illustrated. The larval cases are attached at the distal end, a behaviour that is unique among all known Psychidae. Information on distribution and habitat as well as some ecological data are provided.

Six-weeks Of Resistance Training Is Not Sufficient To Stimulate Bone Response In Older Adults

Aging presents a variety of challenges, ranging from loss of muscle mass, strength, and bone density to functional impairment, risk of fall and fracture. Resistance exercise is known to load the bone and enhance bone density and subsequently strength. However these adaptation typically occur over a long period of time (6+ months). PURPOSE: The purpose of this study was to evaluate whether either dumbbell or elastic band resistance training are beneficial in bone morphology of older adults over 6 weeks of training or a control period. METHODS: Fifty-seven males and females (mean ± SD; age = 66.5 ± 7.09 yrs; height = 165.2 ± 10.6 cm; body mass = 74.5 ± 14.6 kg) volunteered to participate in this study. Participants underwent a total body dual-energy x-ray absorptiometry (DXA) scan for segmental and total body bone mineral content (BMC) and bone mineral density (BMD). Participants were block randomized into one of three groups: elastic band resistance training (EBRT; n = 24), dumbbell resistance training (DBRT; n = 21), or control (CON; n = 12). EBRT and DBRT were asked to visit the laboratory twice weekly over 6-weeks while CON maintained their daily routine. Three-day dietary recalls were collected to ensure dietary maintenance throughout the intervention period. Data were analyzed using a two-way (time x treatment) repeated measures ANOVA and an alpha pre-determined at 0.05. RESULTS: Results indicated there was no two-way interaction for total body BMC (p = 0.164) nor was there a main effect for time (p = 0.39) or group (p = 0.40). Likewise, total body BMD indicated no 2-way interaction (p = 0.79) and no main effect for time (p = 0.753). However, there was a main effect for group where collapsed across time, DBRT had a higher BMD than CON (p = 0.05), but no other differences were observed. CONCLUSIONS: These data suggest that either the load provided throughout the training from DBRT and EBRT to stimulate change in bone over 6-weeks was insufficient or the duration was not long enough. Most previous research supports the latter as bone remodeling occurs in a throughout 4-8 month periods. Other factors that may impact the outcome of the stimuli include exogenous pharmacological treatment for bone loss and dietary factors.

Association between the developing sphenoid and adult morphology: A study using sagittal sections of the skull base from human embryos and fetuses.

The developing sphenoid is regarded as a median cartilage mass (basisphenoid [BS]) with three cartilaginous processes (orbitosphenoid [OS], ala temporalis [AT], and alar process [AP]). The relationships of this initial configuration with the adult morphology are difficult to determine because of extensive membranous ossification along the cartilaginous elements. The purpose of this study was therefore to evaluate the anatomical connections between each element of the fetal sphenoid and adult morphology. Sagittal sections from 25 embryos and fetuses of gestational age 6-34weeks and crown-rump length 12-295mm were therefore examined and compared with horizontal and frontal sections from the other 25late-term fetuses (217-340mm). The OS was identified as a set of three mutually attached cartilage bars in early fetuses. At all stages, the OS-post was continuous with the anterolateral part of the BS. The BS included the notochord and Rathke's pouch remnant in embryos and early fetuses. The dorsum sellae was absent from embryos, but it protruded from the BS in early fetuses before a fossa for the hypophysis became evident. Although not higher than the hypophysis at midterm, the dorsum sellae elongated superiorly after gestational age 25weeks. In early fetuses, the AP was located on the side immediately anterior to the otic capsule. The AT developed on the side immediately posterior to the extraocular rectus muscles. At late term, the greater wing was formed by membranous bones from the AT and AP. The AT and AP formed a complex bridge between the BS and the greater wing. A small cartilage, future medial pterygoid process (PTmed) was located inferior to the AT in early fetuses. At midterm, one endochondral bone and multiple membranous bones formed the PTmed. The lateral pterygoid process (PTlat) was formed by a single membranous bone plate. Therefore, we connected fetal elements and the adult morphology as follows. (1) Derivative of the OS makes not only the lesser wing but also the anterior margin of the body of the sphenoid. (2) Derivatives of the BS are the body of the sphenoid including the sella turcica and the dorsum sellae. (3) Most of the greater wing including the foramen rotundum and the foramen oval originate from the AT and AP and multiple membranous bones. (4) The PTmed originate from endochondral bones and multiple membranous bones, while the PTlat derive from a single membranous bone.

Osteological development of a small and fast metamorphic frog, Microhyla fissipes (Anura, Neobatrachia, Microhylidae).

Describing osteological development is of great importance for understanding vertebrate phenotypic variations, form-functional transitions and ecological adaptations. Anurans exhibit dramatic changes in their morphology, habitat preferences, diet and behaviour between the tadpole and frog stages. However, the anatomical details of their cranial and postcranial development have not been extensively studied, especially in Microhylidae. In this work, we studied the microhylid Microhyla fissipes, commonly known as the ornamented pygmy frog, a small-sized frog with fast metamorphosis. Its osteological development was comprehensively described based on 120cleared and stained specimens, including six tadpoles for each stage between 28 and 45, six juveniles and six adults. Additionally, 22 osteological traits of these specimens involved in food acquisition, respiration, audition and locomotion were selected and measured to reflect the changes in tadpole ecological functions during metamorphosis. Our study provides the first detailed qualitative and quantitative developmental information about these structures. Our results have confirmed that skeletal elements (viz., neopalatines, omosternum, clavicles and procoracoids) absent in adults are not detected during development. Our data reveal that morphologically, radical transformations of the cranial structures related to feeding and breathing are completed within stages 42-45 (72h), but the relative length and width of these skeletons have changed in earlier stages. The postcranial skeletons correlated with locomotion are well developed before stage 42 and approach the adult morphology at stage 45. Indeed, the relative length of the pectoral girdle and forelimb reaches the adult level at stage 42 and stage 45, respectively, whereas that of the vertebral column, pelvic girdle and hind limbs increases from their appearance until reaching adulthood. Based on published accounts of 19species from Neobatrachia, Mesobatrachia and Archaeobatrachia, cranial elements are among the first ossified skeletons in most studied species, whereas sphenethmoids, neopalatines, quadratojugals, mentomeckelians, carpals and tarsals tend to ossify after metamorphosis. These results will help us to better understand the ecomorphological transformations of anurans from aquatic to terrestrial life. Meanwhile, detailed morphological and quantitative accounts of the osteological development of Microhyla fissipes will provide a foundation for further study.

Normal human brainstem development in vivo: aquantitative fetal MRI study.

ABSTRACTObjectivesTo characterize spatiotemporal growth differences of prenatal brainstem substructures and cerebellum, using linear biometry and planimetry on fetal magnetic resonance imaging (MRI).MethodsIn this retrospective study, we included fetuses with normal brain and a precise midsagittal T2‐weighted brain MRI sequence obtained between May 2003 and April 2019. The cross‐sectional area, rostrocaudal diameter and anteroposterior diameter of the midbrain, pons (basis pontis and pontine tegmentum), medulla oblongata and cerebellar vermis, as well as the transverse cerebellar diameter, were quantified by a single observer. The diameters were also assessed by a second observer to test inter‐rater variability.ResultsWe included 161 fetuses with normal brain and a precise midsagittal MRI sequence, examined at a mean ± SD gestational age of 25.7 ± 5.4 (range, 14 + 0 to 39 + 2) weeks. All substructures of the fetal brainstem and the cerebellum could be measured consistently (mean ± SD interobserver intraclass correlation coefficient, 0.933 ± 0.065). We provide reference data for diameters and areas of the brainstem and cerebellum in the second and third trimesters. There was a significant quadratic relationship between vermian area and gestational age, and all other measured parameters showed a significant linear growth pattern within the observed period (P < 0.001). A significant change in the relative proportions of the brainstem substructures occurred between the beginning of the second trimester and the end of the third trimester, with an increase in the area of the pons (P < 0.001) and a decrease in that of the midbrain (P < 0.001), relative to the total brainstem area.ConclusionsThe substructures of the fetal brainstem follow a distinct spatiotemporal growth pattern, characterized by a relative increase in the pons and decrease in the midbrain, between 15 and 40 weeks of gestation. Caution is needed when interpreting fetal brainstem appearance during the early second trimester, as the brainstem proportions differ significantly from the adult morphology. The reference data provided herein should help to increase diagnostic accuracy in detecting disorders of defective hindbrain segmentation. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

A new species of Mycodiplosis gall midge (Diptera: Cecidomyiidae) feeding on myrtle rust Austropuccinia psidii

ABSTRACT Larvae of an undescribed gall midge were found feeding on the rust fungus Austropuccinia psidii that was infecting leaves of trees Lophomyrtus bullata, Lophomyrtus obcordata and Syzygium jambos (all Myrtaceae) in New Zealand. The new species belongs to a cosmopolitan, rust- and mildew-feeding genus Mycodiplosis (Diptera: Cecidomyiidae). The description of Mycodiplosis constricta sp. nov. includes morphology of adults, pupa and larva, and the sequence of a segment of the Cytochrome Oxidase unit I mitochondrial gene. The new species differs from its congeners in an unusual aedeagus and a peculiar male hypoproct. The aedeagus is rounded apically and strongly constricted subapically, bearing subapical setulose sensoria. The hypoproctal lobes are long and narrow, dorsally they are covered with long apical setulae, ventrally they are bare, each lobe bearing a pair of setae of which one is placed apically, the other subapically. The currently known geographical distribution of the new species is confined to the North Island of New Zealand. While it is likely that larvae of the new species decrease numbers of viable uredinia of Austropuccinia psidii, the exact impact of the new species on the population dynamics of the fungal host as a biological control agent and/or a transmission vector remain to be determined. http://zoobank.org/urn:lsid:zoobank.org:pub:3D39F717-49E0-4B46-9033-BE5A244D6A39

Molecular phylogeny of Elmidae (Coleoptera: Byrrhoidea) with a focus on Japanese species: implications for intrafamilial classification

AbstractElmidae (Coleoptera: Byrrhoidea) comprises diverse groups of specialized aquatic beetles, but the phylogenetic positions of the intrafamilial taxonomic groups remain unclear. We performed phylogenetic analyses of 26 genera and 73 elmid species and subspecies representing four of the five currently recognized tribes from Holarctic region (Japan, Europe and North America) using sequence data from up to 585 ultraconserved elements (UCEs). The UCE‐based phylogenetic trees inferred by both maximum‐likelihood and Bayesian inference methods resolved most of the phylogenetic relationships with high support. Our results indicate that a revised classification for the intrafamilial taxonomic groups in Elmidae is necessary. We also examined the correspondence of the character states of ten adult and larval morphological traits to the phylogeny and identified several traits that are potentially useful for defining intrafamilial taxonomic groups in Elmidae. Based on the molecular phylogeny and morphology of adults and larvae, Gonielmis Sanderson syn. n. and Optioservus Sanderson syn. n. are synonymized with Heterlimnius Hinton. Nomuraelmis Satô syn. n. was also synonymized with Stenelmis Dufour. A revised checklist and an identification key to the species groups are provided for Heterlimnius.

Juvenile ecology drives adult morphology in two insect orders.

Most animals undergo ecological niche shifts between distinct life phases, but such shifts can result in adaptive conflicts of phenotypic traits. Metamorphosis can reduce these conflicts by breaking up trait correlations, allowing each life phase to independently adapt to its ecological niche. This process is called adaptive decoupling. It is, however, yet unknown to what extent adaptive decoupling is realized on a macroevolutionary scale in hemimetabolous insects and if the degree of adaptive decoupling is correlated with the strength of ontogenetic niche shifts. It is also unclear whether the degree of adaptive decoupling is correlated with phenotypic disparity. Here, we quantify nymphal and adult trait correlations in 219 species across the whole phylogeny of earwigs and stoneflies to test whether juvenile and adult traits are decoupled from each other. We demonstrate that adult head morphology is largely driven by nymphal ecology, and that adult head shape disparity has increased with stronger ontogenetic niche shifts in some stonefly lineages. Our findings implicate that the hemimetabolan metamorphosis in earwigs and stoneflies does not allow for high degrees of adaptive decoupling, and that high phenotypic disparity can even be realized when the evolution of distinct life phases is coupled.

And thereby hangs a tail: morphology, developmental patterns and biomechanics of the adhesive tails of crested geckos (Correlophus ciliatus).

Among the most specialized integumentary outgrowths in amniotes are the adhesive, scale-like scansors and lamellae on the digits of anoles and geckos. Less well-known are adhesive tail pads exhibited by 21 gecko genera. While described over 120 years ago, no studies have quantified their possible adhesive function or described their embryonic development. Here, we characterize adult and embryonic morphology and adhesive performance of crested gecko (Correlophus ciliatus) tail pads. Additionally, we use embryonic data to test whether tail pads are serial homologues to toe pads. External morphology and histology of C. ciliatus tail pads are largely similar to tail pads of closely related geckos. Functionally, C. ciliatus tail pads exhibit impressive adhesive ability, hypothetically capable of holding up to five times their own mass. Tail pads develop at approximately the same time during embryogenesis as toe pads. Further, tail pads exhibit similar developmental patterns to toe pads, which are markedly different from non-adhesive gecko toes and tails. Our data provide support for the serial homology of adhesive tail pads with toe pads.

Phylogenetic systematics of the genera of Thryptocerina Jeannel, 1949 and new species from New Caledonia (Coleoptera, Carabidae, Oodini).

The Oodini precinctive to New Caledonia are reviewed with nine species recognized, of which seven are newly described in two genera. Five species are described in the genus Coptocarpus Chaudoir: C. micropssp. nov., C. erwinisp. nov., C. amieuensissp. nov., C. magnussp. nov., and C. leschenisp. nov. In the genus Adelopomorpha Heller two species, A. tethyssp. nov. and A. tuberculatasp. nov., are described. In order to place cladistically the newly described species in a genus, a phylogenetic analysis of a matrix of 36 characters of adult morphology was conducted including exemplar species of three putative outgroup genera, six putative ingroup thryptocerine oodine genera, and all oodine species from New Caledonia. Results show support for Thryptocerina and monophyly of Adelopomorpha. Hoplolenus LaFerté-Sénectère is not monophyletic and Hoplolenus cyllodinus Fauvel is newly combined as Coptocarpus cyllodinuscomb. nov. New Caledonian species of Coptocarpus form a clade, but the Australian species of the genus included in the analysis are rendered paraphyletic by African and Malagasy genera. Implications of this preliminary study for the classification of Oodini and trends in the evolution of the female reproductive tract are discussed. A key to the New Caledonian species of Oodini is provided.

A new species of the genus Luzulaspis (Hemiptera: Coccomorpha: Coccidae) from Hokkaido Island, Japan.

A new species of soft scale insect (Hemiptera: Coccomorpha: Coccidae), Luzulaspis kinakikir Tanaka sp. nov., collected from Carex miyabei (Cyperaceae), on Hokkaido Island, Japan, is described and illustrated based on adult female morphology. The new species, which belongs to the Scotica group of Luzulaspis, is similar to L. filizae Kaydan, 2015, but can be distinguished from it by possessing multilocular pores with fewer loculi; numerous dorsal tubular ducts, obviously wider than the ventral tubular ducts, and by lacking dorsal tubular ducts on the head apex. An updated diagnosis of Luzulaspis and two identification keys, one to the Japanese species of Luzulaspis and the other to the species of the Scotica group of Luzulaspis, are provided.

Pesticide Exposure During Development Does Not Affect the Larval Pheromones, Feeding Rates, or Morphology of Adult Honey Bee (Apis mellifera) Queens

Recent work demonstrated that honey bee (Apis mellifera L.) queens reared in pesticide-laden beeswax exhibit significant changes in the composition of the chemicals produced by their mandibular glands including those that comprise queen mandibular pheromone, which is a critical signal used in mating as well as queen tending behavior. For the present study, we hypothesized that pesticide exposure during development would alter other queen-produced chemicals, including brood pheromone in immature queens, thus resulting in differential feeding of queen larvae by nurse workers, ultimately impacting adult queen morphology. We tested these hypotheses by rearing queens in beeswax containing field-relevant concentrations of (1) a combination of tau-fluvalinate and coumaphos, (2) amitraz, or (3) a combination of chlorothalonil and chlorpyrifos. These pesticides are ubiquitous in most commercial beekeeping operations in North America. We observed nurse feeding rates of queen larvae grafted into pesticide-laden beeswax, analyzed the chemical composition of larval queen pheromones and measured morphological markers in adult queens. Neither the nurse feeding rates, nor the chemical profiles of immature queen pheromones, differed significantly between queens reared in pesticide-laden wax compared to queens reared in pesticide-free wax. Moreover, pesticide exposure during development did not cause virgin or mated adult queens to exhibit differences in morphological markers (i.e., body weight, head width, or thorax width). These results were unexpected given our previous research and indicate that future work is needed to fully understand how pesticide exposure during development affects honey bee queen physiology, as well as how various adult queen quality metrics relate to each other.

An Updated Staging System for Cephalochordate Development: One Table Suits Them All.

Chordates are divided into three subphyla: Vertebrata, Tunicata, and Cephalochordata. Phylogenetically, the Cephalochordata, more commonly known as lancelets or amphioxus, constitute the sister group of Vertebrata and Tunicata. Lancelets are small, benthic, marine filter feeders, and their roughly three dozen described species are divided into three genera: Branchiostoma, Epigonichthys, and Asymmetron. Due to their phylogenetic position and their stereotypical chordate morphology and genome architecture, lancelets are key models for understanding the evolutionary history of chordates. Lancelets have thus been studied by generations of scientists, with the first descriptions of adult anatomy and developmental morphology dating back to the 19th century. Today, several different lancelet species are used as laboratory models, predominantly for developmental, molecular and genomic studies. Surprisingly, however, a universal staging system and an unambiguous nomenclature for developing lancelets have not yet been adopted by the scientific community. In this work, we characterized the development of the European lancelet (Branchiostoma lanceolatum) using confocal microscopy and compiled a streamlined developmental staging system, from fertilization through larval life, including an unambiguous stage nomenclature. By tracing growth curves of the European lancelet reared at different temperatures, we were able to show that our staging system permitted an easy conversion of any developmental time into a specific stage name. Furthermore, comparisons of embryos and larvae from the European lancelet (B. lanceolatum), the Florida lancelet (Branchiostoma floridae), two Asian lancelets (Branchiostoma belcheri and Branchiostoma japonicum), and the Bahamas lancelet (Asymmetron lucayanum) demonstrated that our staging system could readily be applied to other lancelet species. Although the detailed staging description was carried out on developing B. lanceolatum, the comparisons with other lancelet species thus strongly suggested that both staging and nomenclature are applicable to all extant lancelets. We conclude that this description of embryonic and larval development will be of great use for the scientific community and that it should be adopted as the new standard for defining and naming developing lancelets. More generally, we anticipate that this work will facilitate future studies comparing representatives from different chordate lineages.

Size, microhabitat, and loss of larval feeding drive cranial diversification in frogs

Habitat is one of the most important factors shaping organismal morphology, but it may vary across life history stages. Ontogenetic shifts in ecology may introduce antagonistic selection that constrains adult phenotype, particularly with ecologically distinct developmental phases such as the free-living, feeding larval stage of many frogs (Lissamphibia: Anura). We test the relative influences of developmental and ecological factors on the diversification of adult skull morphology with a detailed analysis of 15 individual cranial regions across 173 anuran species, representing every extant family. Skull size, adult microhabitat, larval feeding, and ossification timing are all significant factors shaping aspects of cranial evolution in frogs, with late-ossifying elements showing the greatest disparity and fastest evolutionary rates. Size and microhabitat show the strongest effects on cranial shape, and we identify a “large size-wide skull” pattern of anuran, and possibly amphibian, evolutionary allometry. Fossorial and aquatic microhabitats occupy distinct regions of morphospace and display fast evolution and high disparity. Taxa with and without feeding larvae do not notably differ in cranial morphology. However, loss of an actively feeding larval stage is associated with higher evolutionary rates and disparity, suggesting that functional pressures experienced earlier in ontogeny significantly impact adult morphological evolution.

520 A Cone-Beam Computed Tomography Study on the Impact of Bruxism in Craniomandibular Morphology of Adults. Preliminary findings

Abstract Introduction Although bruxism, either during awake and during sleep is still a controversial topic in contemporary Medicine, its prevalence and its putative relationship with several conditions interfering with health and wellbeing make it relevant as a target to be studied in distinct scientific domains. Histological and morphological on the craniomandibular complex (CC) have been documented with different techniques. However, there is a lack of high quality imaging studies showing structural changes among the different anatomical structures therefore leading to a misinterpretation of the real impact of bruxism on such elements.The aim of this clinical retrospective comparative study was to investigate whether there are structural differences on the craniomandibular complex of bruxers in face to non-bruxers evaluated by a cone-beam computed tomohraphy (CBCT). We present the preliminary findings of this still ongoing study. Methods A retrospective analysis of CBCT imaging exams from patients with ages between 18 and 44 years old, were distributed among 1) bruxism group:BG (n=31); 2) Non-bruxism/Control group (n=21). Bruxism diagnosis followed non-instrumental approach suggested by the bruxism consensus 2013. To the craniomorphological evaluation, 3D CBCT SYM Diagnosis protocol was implemented by a calibrated expert at an adequate local with reduced light. Photograpic parameters were analyzed according to standard procedures. Results Female gender prevailed without differences between groups (61,3% in BG and 66,7 in CG; p=0,91). Age of BG was significantly higher than CG (40,1 yo versus 28,4;p=0,002). Mandibular structure as inferred by its shape was significantly higher in BG compared with CG. Conclusion In this preliminary study the CBCT 3D image showed important and significant changes in mandibular structure in bruxers compared with non-bruxers. Support (if any):