Supernumerary Elements Research Articles

Surgical Treatment of Supernumerary Elements for Orthodontic Purposes: Clinical Case Report

Introduction: Hyperdontia is a type of dental development disorder linked to various factors, characterized by an excessive number of teeth in relation to the normal dental formula. This anomaly can affect both jaws and dentitions, but the anterior maxillary region and the permanent dentition are the most affected, and it is more prevalent in male patients. Early diagnosis and immediate treatment are of the utmost importance to avoid complications. Objective: To describe a surgical procedure involving the removal of bilateral mandibular supernumerary teeth in a 17-year-old patient for orthodontic purposes. Materials and Methods: This is a descriptive study of a clinical case, carried out by a student and a team of professors from the postgraduate course in minor oral surgery, at the Dentistry school clinic of the Integrated College of Patos (UNIFIP). The procedure was carried out in two surgical procedures, with a 30-day interval between the surgeries. Conclusion: There are several consequences that supernumerary elements can cause and this case report raises awareness and provides evidence for the clinical characterization and optimal treatment of supernumerary teeth.

Transcribing the enigma: the B chromosome as a territory of uncharted RNAs.

B chromosomes are supernumerary elements found in several groups of eukaryotes, including fungi, plants, and animals. Typically, these chromosomes either originate from their hosts through errors in meiosis or interspecifically through horizontal transfer. While many B chromosomes are primarily heterochromatic and possess a low number of coding genes, these additional elements are still capable of transcribing sequences and exerting influence on the expression of host genes. How B chromosomes escape elimination and which impacts can be promoted in the cell always intrigued the cytogeneticists. In pursuit of understanding the behavior and functional impacts of these extra elements, cytogenetic studies meet the advances of molecular biology, incorporating various techniques into investigating B chromosomes from a functional perspective. In this review, we present a timeline of studies investigating B chromosomes and RNAs, highlighting the advances and key findings throughout their history. Additionally, we identified which RNA classes are reported in the B chromosomes and emphasized the necessity for further investigation into new perspectives on the B chromosome functions. In this context, we present a phylogenetic tree that illustrates which branches either report B chromosome presence or have functional RNA studies related to B chromosomes. We propose investigating other unexplored RNA classes and conducting functional analysis in conjunction with cytogenetic studies to enhance our understanding of the B chromosome from an RNA perspective.

A new genus and species of oceanic planktonic Tisbidae (Crustacea, Copepoda, Harpacticoida) with enlarged modified eyes.

Both sexes of a new monotypic genus of Tisbidae (Copepoda, Harpacticoida) are described from the epi- or mesopelagic zone in the Kuroshio region, Japan. Gyoromeguttatumgen. et sp. nov. belongs to a monophyletic lineage of deepwater holoplanktonic genera defined by a suite of characters. Within this clade, Gyoromegen. nov. appears most closely related to Neotisbella Boxshall, 1979. The most distinguishable feature of G.guttatumgen. et sp. nov. is the presence of large, paired, frontal modified eyes, each consisting of a baculiform ocellus, a globular (Gicklhorn's?) organ, and a semi-parabolic plate. The taxonomic position of Tisbespinulosa Bradford & Wells, 1983 is discussed and a key to the six meso- and bathypelagic tisbid species is provided. Confusion surrounding earlier literature reports of supernumerary elements on the caudal ramus in some harpacticoid taxa is clarified. Secondary modifications of ocellar components of the typical naupliar eye in the Harpacticoida are reviewed. It is suggested that the development of specialized eyes in G.guttatumgen. et sp. nov. may provide a means for detecting bioluminescent food particles in oligotrophic pelagic environments. The large, vaulted prosome indicates the species is an opportunistic macrophage that has adopted gorging as a feeding strategy.

A single origin for the widely distributed B chromosomes of the gladiator frog Boana albopunctata

Abstract B chromosomes are supernumerary elements that have a wide taxonomic distribution among eukaryotes. Although they are dispensable, they can acquire mechanisms to be overrepresented in the next generation and therefore avoid being eliminated. These elements have been discovered in < 2% of the karyotyped anurans. B chromosomes were described for Argentine and Brazilian populations of Boana albopunctata, a Neotropical tree frog widely distributed in the central region of South America. We assessed the distribution of B chromosomes in this species via cytogenetic studies of 365 specimens from Argentina, Brazil and Paraguay. We found that 101 individuals carried B chromosomes, with striking differences in their frequency of occurrence among localities. Our findings might be related to the evolutionary dynamics of these elements. Microdissection and chromosome painting experiments demonstrated sequence similarity between B chromosomes from localities that are > 1000 km apart, showing the most widely distributed B chromosome system known for anurans. The B chromosome system of B. albopunctata might help to fill the general knowledge gap for these elements in anurans compared with other vertebrates.

Class I treatment with severe dental crowding and mandibular protrusion: a case report

The use of Corrective Orthodontics to modifying dental aesthetics, has been increasingly effective in modifying and improving the profile of patients. Objective: Review the literature on the treatment of Cl I malocclusions with severe dental crowding and to report a clinical case performed in the dental clinic of a private educational institution. Methodology: After dental extraction and fixed orthodontic appliance treatment, the facial and dental aesthetics patient evolution with the diastema presence between dental elements 11 and 21 and supernumerary elements. The case was treated in two phases, with the aim of correcting the dental crowding. In the first phase, the first premolars and a supernumerary tooth were extracted, to initiate the isolated canine retraction and, later, the space closures by means of the retraction of the incisors. In the second phase, after the closure of spaces, the intrusion and molarization verticalization phase was started. For the subject review in case, articles were searched in the Pubmed databases, Lilacs and Scielo and selected 8 articles between the years 2010 and 2019.Results and Conclusions: It was observed that the exodontia provided the necessary spaces for the alignment and leveling of the teeth and the intrusion and mandibular rotation of the molars allowed the mandible to rotate counter clockwise, reducing the convex profile of the patient. At the end of the treatment, a facial response was observed according to the mechanics employed and significant improvement in the dental, facial aesthetics and, consequently, social improvement of the patient.

Autotransplantation of conoid maxillary third molar in upper incisive site: A reliable aesthetic solution

In the management of anterior dental trauma, the maintenance of the traumatized elements has to be preferred, but sometimes this results impracticable. Among different options, autotransplantation provides an adequate therapeutic solution, particularly in crowded arches, in presence of supernumerary elements or when third molars with a root anatomy compatible with the recipient site are available.: This paper presents a case of autotransplantation of a conoid upper third molar (1.8) inside the alveolus of a central incisor undergone at root resorption, after a long time maintenance of the traumatized element 2.1 and different treatments. Furthermore, a comparison of the therapeutic alternatives is proposed. : Due to their root anatomy, premolars and supernumerary monoradiculated teeth are adequate to be transplanted in incisors’ sockets. In the presented case, the presence of a conoid third molar consented the transplantation of the latter, which represented a more conservative treatment than transplanting a premolar. The use of a 3D-printed replica made through a CBCT scan permitted the substantial reduction of the extra alveolar time, avoiding the periodontal ligament contamination and guaranteeing a higher success rate. Due to the complete formation of the donor tooth, root canal treatment was carried out. Autotransplantation represents a valid and biological alternative in the management of traumas of the anterior dental trauma.

Chromosomal Instability and Origin of B Chromosomes in the Amazonian Glass Tetra Moenkhausia oligolepis (Günther, 1864) (Characiformes, Characidae)

B chromosomes occur in different species of the small characid fishes of the genus Moenkhausia. These supernumerary elements, that do not recombine with chromosomes of the standard A complement and follow their own evolutionary mechanism vary in number, morphology, and distribution. Here, we show karyotypic data of individuals of 2 populations of Moenkhausia oligolepis of the Brazilian Amazon (Pedro Correia and Taboquinha streams, Tocantins river basin), both with a diploid number of 50 chromosomes and karyotypic formula of 10m + 32sm + 8a. In addition to the normal complement, we also observed the occurrence of B chromosomes in the 2 populations with intra- and interindividual variation ranging from 0 to 10 Bs, independent of sex. The C-banding pattern evidenced heterochromatic blocks located mainly in the pericentromeric region of the chromosomes, while the B chromosomes appeared euchromatic. Silver-stained nucleolus organizer regions were identified in multiples sites, and some of these blocks were positive when stained with chromomycin A_3. The karyotype analysis and the application of whole-chromosome painting in populations of M. oligolepis reinforce the conservation of the basal diploid number for the genus, as well as the evolutionary tendency in these fishes to carry B chromosomes. Both populations turned out to be in different stages of stability and expansion of their B chromosomes. We further suggest that the origin of these chromosomes is due to the formation of isochromosomes. Here, we identified a pair of complement A chromosomes involved in this process.

Mapping of supernumerary elements in patients seeking orthodontic treatment

Introduction: Dimension, number and shape alterations are frequently observed dental anomalies. Objective: The aim of this study was to map the frequency, the preferred location and the most prevalent types of supernumerary teeth, in the studied population. In addition, to assess the interference that supernumeraryteeth may cause in the ectopic eruption of the normal dental series teeth. Methods: This is an observational retrospective study. Data collection was performed by evaluation of dental records of patients treated in an orthodontic clinic. Patients‘ radiographs, photographs and gypsum dental models were analyzed and datarecorded in protocol files, by previously trained undergraduate and postgraduate students. Records from 1984 to 2019 were evaluated, and evaluation lasted two months. Data were stored in Microsoft Office Excel (version 2016) for descriptive analysis. Results: From the 920 patients’ records analyzed, 2.7% presented atleast one supernumerary tooth, with preferred location on the anterior maxillary area and mandibular parapremolar area. The most prevalent type was the supplemental tooth, with normal eruption orientation and normal alveolar location. Conclusion: The supernumerary teeth of the studied population showedlittle interference in the ectopic eruption of the normal dental series. Most of the supernumerary teeth were impacted, and, approximately one third of the supernumerary teeth showed deviated eruptions.

First report on B chromosome content in a reptilian species: the case of Anolis carolinensis.

Supernumerary elements of the genome are often called B chromosomes. They usually consist of various autosomal sequences and, because of low selective pressure, are mostly pseudogenized and contain many repeats. There are numerous reports on B chromosomes in mammals, fish, invertebrates, plants, and fungi, but only a few of them have been studied using sequencing techniques. However, reptilian supernumerary chromosomes have been detected only cytogenetically and never sequenced or analyzed at the molecular level. One model squamate species with available genome sequence is Anolis carolinensis. The scope of the present article is to describe the genetic content of A. carolinensis supernumerary chromosomes. In this article, we confirm the presence of B chromosomes in this species by reverse painting and synaptonemal complex analysis. We applied low-pass high-throughput sequencing to analyze flow-sorted B chromosomes. Anole B chromosomes exhibit similar traits to other supernumerary chromosomes from different taxons: they contain two genes related to cell division control (INCENP and SPIRE2), are enriched in specific repeats, and show a high degree of pseudogenization. Therefore, the present study confirms that reptilian B chromosomes resemble supernumerary chromosomes of other taxons.

Landscape of Transposable Elements Focusing on the B Chromosome of the Cichlid Fish Astatotilapia latifasciata.

B chromosomes (Bs) are supernumerary elements found in many taxonomic groups. Most B chromosomes are rich in heterochromatin and composed of abundant repetitive sequences, especially transposable elements (TEs). B origin is generally linked to the A-chromosome complement (A). The first report of a B chromosome in African cichlids was in Astatotilapia latifasciata, which can harbor 0, 1, or 2 Bs Classical cytogenetic studies found high a TE content on this B chromosome. In this study, we aimed to understand TE composition and expression in the A. latifasciata genome and its relation to the B chromosome. We used bioinformatics analysis to explore the genomic organization of TEs and their composition on the B chromosome. The bioinformatics findings were validated by fluorescent in situ hybridization (FISH) and real-time PCR (qPCR). A. latifasciata has a TE content similar to that of other cichlid fishes and several expanded elements on its B chromosome. With RNA sequencing data (RNA-seq), we showed that all major TE classes are transcribed in the brain, muscle, and male and female gonads. An evaluation of TE transcription levels between B- and B+ individuals showed that few elements are differentially expressed between these groups and that the expanded B elements are not highly transcribed. Putative silencing mechanisms may act on the B chromosome of A. latifasciata to prevent the adverse consequences of repeat transcription and mobilization in the genome.

Canine Eruption After Secondary Alveolar Bone Graft in Unilateral Cleft Lip and Palate Patients.

The aim of this article is to analyze dental abnormalities in unilateral cleft lip and palate patients by focusing on the role of the secondary alveolar bone graft (SABG) surgery and its outcomes on canine eruption/inclusion. A sample of 24 patients with unilateral cleft lip and palate were selected.Dental anomalies, canine eruption based on the existence of supernumeraries, agenesis elements, inclination of the major canine axis before and after surgery, distance from the occlusal plane before and after surgery, and sector classification were analyzed. Out of the 24 patients, 87.5% presented a canine spontaneously erupted in the dental arch while 12.5% needed surgical-orthodontic traction.There is also no proof that inclination of the canine significantly influenced the eruption before (P = 0.5889) and after (P = 0.4029) surgery. Also, there is no any correlation between the 2 sides (P = 0.1257).The SABG surgery showed a significant correlation with canine eruption (P = 0.009242); moreover, SABG shows a positive relationship with the radicular development of the canine (P = 0.005163).Lateral incisive (P = 0.8493) and second premolar agenesis (P = 1) are not statistically correlated with the eruption of the canine. This does not happen with supernumerary elements that are correlated with the surgical-orthodontic traction (P = 0.0004464). Agenesis does not play any role in the process of canine eruption while supernumeraries do. There is no relationship between the inclination and eruption of the canine.The SABG surgery has a key role because it contributes to create an appropriate support for the erupting canine, the nasal base and the anterior maxilla.

Transmission rate variation among three B chromosome variants in the fish Prochilodus lineatus (Characiformes, Prochilodontidae)

Cytogenetic studies were developed in Prochilodus lineatus (Valenciennes 1836), describing an interesting system of small supernumerary chromosomes. The purpose of this work is to study the frequency and morphology of B chromosomes in individuals from the parental line and the inheritance patterns of these elements in individuals obtained from controlled crosses in the species P. lineatus. The transmission rate of B chromosomes revealed a k(B)=0.388 for the acrocentric type, a kB=0.507 for the metacentric type and a k(B)=0.526 for the submetacentric type. The obtained results raise hypothesis that B-acrocentric chromosomes are involved in an extinction process in this species, while the metacentric and submetacentric supernumerary elements comprises a neutral mechanism and follows a Mendelian transmission rate.

A comparison between various radiological techniques in the localization and analysis of impacted and supernumerary teeth

An increasing number of different types of commercial cone-beam computed tomography (CBCT) devices are available for three-dimensional (3D) imaging in the field of dental and maxillofacial radiology. When removing impacted or supernumerary teeth, surgical teams often operate adjacent significant anatomical structures such as nerves, vessels, adjacent teeth roots, and paranasal sinuses. It is therefore important to choose the appropriate surgical approach to avoid iatrogenic damage to the essential anatomical neighbouring structures. CBCT, also called digital volume tomography (DVT), can visualize impacted and supernumerary teeth in all standard planes, as well as multisectional 3D views. These devices have shown to be highly beneficial in the assessment of small bony lesions and maxillofacial injuries. However, it is still necessary to determine the effectiveness of such devices in the assessment of impacted and supernumerary teeth, in comparison to the conventional radiological methods of intraoral X-rays and panoramic X-rays. During a period of 2 years, a total of 61 patients of whom majority had impacted teeth or supernumerary elements in the frontal maxillary region were studied with CBCT and treated at the St. Olavs University Hospital. Patients were referred to our Department of Oral and Maxillofacial Surgery with both conventional and digital intraoral X-rays and/or panoramic X-rays. None had any acute infections or odontogenic abscesses, and most presented with asymptomatic impacted tooth. A comparison between the preoperative conventional and the CBCT images, the resulting diagnoses, and the intraoperative findings as "gold standard" were made and recorded in a compiled scoring sheet. The objects of interest were researched with the magnification method. Each patient was identified only with a patient number. In contrast to the conventional X-rays, the pre-surgical evaluation with the CBCT revealed detailed imaging of significant anatomical structures and objects of interest, with highly accurate anatomical and morphologic imaging, when compared to the intraoperative findings. Furthermore, no diagnostic problems, in relation to the anatomical localization, occurred preoperatively. The CBCT provides true and precise anatomical information with high surgical predictability without distortion or artefacts, and is superior to conventional radiography. It enables more time-efficient surgeries and reduces costs and surgical complications.

B Chromosomes in the Tree FrogHypsiboas albopunctatus(Anura: Hylidae)

Supernumerary or B chromosomes are one of the main causes for numerical chromosomal variation in higher eukaryotes. These extragenetic elements have been studied for more than a century, with the goal of trying to understand their origin, and how they survive as a polymorphism in natural populations. Hypsiboas albopunctatus is a nocturnal hylid frog distributed in the central-eastern part of South America. Previously, variation in chromosome numbers was described for a population from Rio Claro, Sao Paulo, Brazil, in which a single small-sized, metacentric B chromosome was present in ca. 40% of the analyzed individuals (n ¼ 17). We herein describe the presence of B chromosomes in populations of H. albopunctatus from northeastern Argentina (Corrientes and Misiones provinces), with unusual morphological and structural characteristics. The frequency of B chromosomes varied significantly among analyzed populations. We found four diploid numbers (2N ¼ 22, 22 þ 1B, 22 þ 2B, and 22 þ 3B), and in a few individuals mitotic instability occurred. C banding revealed variations in the heterochromatin (DAPIþ) pattern between Bs with similar morphology, indicating the existence of two new structural variants of these supernumerary elements in H. albopunctatus (B1 and B2). Nucleolar organizer regions marked positively on the eighth pair, coincident with the location of ribosomal DNA as demonstrated with fluorescent in situ hybridization, but Bs did not mark positive with these two techniques. Also, fluorescent in situ hybridization with telomeric probes showed no differences in location and intensity between Bs and autosomal chromosomes. The present communication is the first case of B chromosome polymorphisms in hylid frogs and the sixth reported in Anura.

Normal axial skeleton structure in common roach Rutilus rutilus (Actinopterygii: Cyprinidae) and malformations due to radiation contamination in the area of the Mayak (Chelyabinsk Province, Russia) nuclear plant

This study was designed to describe normal axial skeletal structure in common roach Rutilus rutilus from putative unaffected environmental conditions, and the occurrence of skeletal malformations in the fish from an area under radiation contamination. Specimens were collected from water bodies of the Techa Cascade Reservoirs located near the Mayak atomic industry plant in the River Ob' drainage, Chelyabinsk Province, Russia. One sample was collected from Lake Irtyash, a reservoir of drinkable water, supplying the town of Ozersk, and the other one from a technical reservoir which is a storage of liquid radioactive waste from Mayak and characterized by high radioactive contamination (mostly (90)Sr and (137)Cs). A comparison was made with historical material collected from the River Ob' before the middle of the 20th century, i.e. before the environment became affected by radioactive contamination. A high number of abnormalities of the axial skeleton were detected in both Mayak samples, in 94 and 97% of examined specimens, in contrast to about 20% in the historical specimens. The abnormalities were in both the unpaired fins and the vertebral column, including the caudal complex and included supernumerary elements, fusions, deformities and displacement of the elements. Most axial skeleton abnormalities, however, were minor, such as splitting, shortening or deformation of spines. Severe defects, such as extensive scolioses, lordoses and kyphoses, were not found. The causes of the abnormalities were not identified in this study, but the high incidence of malformations may be attributed to genetically determined imbalance during development. The almost equal distribution of abnormalities among the fish from non-contaminated and radioactive contaminated reservoirs may be explained by either recent gene flow within the population of R. rutilus in the River Techa system or the effect of unknown unfavourable environmental factors such as chemical pollution.

Anchoring the dog to its relatives reveals new evolutionary breakpoints across 11 species of the Canidae and provides new clues for the role of B chromosomes

The emergence of genome-integrated molecular cytogenetic resources allows for comprehensive comparative analysis of gross karyotype architecture across related species. The identification of evolutionarily conserved chromosome segment (ECCS) boundaries provides deeper insight into the process of chromosome evolution associated with speciation. We evaluated the genome-wide distribution and relative orientation of ECCSs in three wild canid species with diverse karyotypes (red fox, Chinese raccoon dog, and gray fox). Chromosome-specific panels of dog genome-integrated bacterial artificial chromosome (BAC) clones spaced at ∼10-Mb intervals were used in fluorescence in situ hybridization analysis to construct integrated physical genome maps of these three species. Conserved evolutionary breakpoint regions (EBRs) shared between their karyotypes were refined across these and eight additional wild canid species using targeted BAC panels spaced at ∼1-Mb intervals. Our findings suggest that the EBRs associated with speciation in the Canidae are compatible with recent phylogenetic groupings and provide evidence that these breakpoints are also recurrently associated with spontaneous canine cancers. We identified several regions of domestic dog sequence that share homology with canid B chromosomes, including additional cancer-associated genes, suggesting that these supernumerary elements may represent more than inert passengers within the cell. We propose that the complex karyotype rearrangements associated with speciation of the Canidae reflect unstable chromosome regions described by the fragile breakage model.

Intraspecific crosses resulting in the first occurrence of eight and nine B chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae).

B chromosomes are supernumerary elements present in about 15% of eukaryotic species and are most frequently heterochromatic, behave parasitically, show a transmission rate higher than standard (A) chromosomes, and can provoke harmful effects on carriers. In the current work, Prochilodus lineatus individuals carrying eight and nine B chromosomes were obtained by induced crossing performed involving breeders with different B chromosome numbers in their cells. The high B chromosome numbers found in the offspring were recorded for the first time in this species. The use of cytogenetic techniques applied in the present study revealed that regardless of the increase in number of B chromosomes in the genome of these individuals, those elements did not presented active genes, and showed their normal heterochromatic characteristic.

B chromosomes in populations of yellow‐necked mice – stowaways or contributing genetic elements?

B chromosomes (Bs) are supernumerary elements to the standard chromosome set, characterized by a dispensable nature. They are maintained like parasites if they possess any mechanism of accumulation. Otherwise, they must confer some selective advantage to the carriers. Some evidence for a beneficial effect led to the dominating opinion that Bs are genomic parasites. Populations of the yellow‐necked mouse, Apodemus flavicollis, are characterized by a frequent presence of Bs, even though no mechanism for their accumulation has been found. Head morphology was compared in three populations of this species with different frequencies of animals with Bs (fB). Two of the localities (Mt. Avala, fB = 0.37 and Mt. Cer, fB = 0.31) are typical forest habitats and are about 100 km far from each other, while the third locality (Ada, fB = 0.19) is a quite different habitat located less than 5 km from Mt. Cer. Discriminant analysis of morphological traits separated the locality Ada from Mt. Avala, while the population from Mt. Cer, besides its internal variation, included variation from both other localities (Ada‐like and Mt. Avala‐like). The frequency of animals with Bs in the Ada‐like group (in the Mt. Cer population) was significantly different from that in the Ada population (0.19 vs. 0.43). Differences in fB, found in phenotypically/genotypically similar groups in different habitats, point to the existence of adaptive effects of Bs at the level of populations.

Identification and description of distinct B chromosomes in Cyphocharax modestus (Characiformes, Curimatidae)

Cytogenetic analyses were performed in Cyphocharax modestus, collected at Paranapanema River and Tiete River (Sao Paulo State, Brazil). A karyotype with 2n = 54 chromosomes was observed in the animals from both Brazilian freshwater river systems. One to four B chromosomes were also detected in individuals from the Paranapanema River, which represents the probable first report of more than a single supernumerary element in a species of the Curimatidae group. C-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of C. modestus. Moreover, while some B chromosomes were characterized by the complete absence of C-bands, others were totally heterochromatic. Although there was a prevalence of B chromosomes in males of C. modestus, at least one supernumerary element was found in males and/or females of several other populations of the species, which suggests that the presence of these chromosomes seems to represent a general trait of C. modestus. A possible origin of the described B chromosomes may be related to the occurrence of a chromosome non-disjunction followed by the loss of euchromatic segments, an event that should have occurred in chromosomes that present conspicuous centromeric heterochromatic blocks and even in chromosomes that lack C-bands in this region, resulting in small supernumerary elements.

OBSERVATION ON SKELETAL DEFORMITY IN HATCHERY-REARED RED SPOTTED GROUPER, Epinephelus akaara (Temmick et Schlegel) FROM LARVAL TO JUVENILE STAGE

Skeletal deformity is a significant problem in fish culture. The skeletal deformities in red spotted grouper from yolk-sac to juvenile stages were examined through clearing and staining of the cartilage and bone using Alcian Blue and Alizarin Red S. The overall results showed that the pattern of incidence of deformities showed an increase from preflexion to juvenile stages. The rate of deformities based on ten elements of bone from preflexion to juvenile stages were as follows: vertebral (42.6%—9.0%), dorsal proximal radials (4.8%—25.2%), neural spine (0%—8.4%), haemal spine (0%—6.8%), hypural (1.3%—5.4%), anal proximal radials (0%—5.4%), epural (1.3%—4.9%), arypural (2.0%—4.5%), lower jaw (1.3%—2.5%), and upper jaw (0%). Vertebral and dorsal proximal radials were recognized as the most susceptible parts to deformation. The main types of bone deformity were lordosis, scoliosis, fusion, shortening, branching, supernumerary elements, and saddleback syndrome. Development of saddleback syndrome was detected initially in preflexion stage, which was accompanied by deformity of the neural spines, dorsal proximal radials, and disposition of the distal radials and dorsal spines in later life stages. The skeletal deformity encountered during the larval rearing period could be caused by water surface tension.