Caudal Fin Length Research Articles

Sexual dimorphism in the dwarf round ray Urotrygon nana.

This paper presents information on the morphological, morphometric, and dental sex differences in the dwarf round ray Urotrygon nana. We recorded 12 morphological traits, sex, the distribution pattern of dermal denticles, the number of tooth rows, and the tooth shape of 466 individuals. The disc width of females ranged from 50 to 172 mm and that of males ranged from 53 to 135 mm. A neuronal classification model and a correspondence analysis showed that female disc width was 21.5% broader, and the distance from the rostrum to the anus was 17.7% longer than that of males, whereas males presented 19.5% greater distance between the nostrils, 9.7% greater preorbital snout length, 6.8% greater cloaca to caudal-fin length, 2.7% greater interorbital distance, and 1.1% greater total length than females. The disc of adult males, including the abdominal cavity area, was densely covered with dermal denticles, which were slightly larger than those observed in females. Females presented homodont dentition with molariform teeth and a smooth lozenge-shaped crown with rounded margins. Males exhibited homodonty but with tooth morphology variations in individuals of different sizes (from molariforms to sharper cusp teeth). There were changes in disc shape (from subcircular to oval), distribution and size of dermal denticles (more abundant and larger), and tooth shape (from molariform to monocuspid teeth) during male development, from neonates to adults. U. nana exhibited sexual dimorphism in size, disc shape, number and shape of teeth, and distribution and size of dermal denticles.

Taxonomic characterization of five species of emperor fishes (Actinopterygii: Eupercaria: Lethrinidae) based on external morphology, morphometry, and geographic distribution in the northwestern Indian Ocean

Species of the genus Lethrinus, commonly referred to as emperor fishes, mainly distributed in the Indo–West Pacific, including the Persian Gulf and Gulf of Oman are poorly known. It is difficult to characterize them morphologically, as there are no distinguishing meristic features for the majority of species. We studied the morphological features of 65 specimens representing the genus Lethrinus to define and identify the species involved. Among the morphological characters commonly considered in this type of study, we also included new, previously undescribed characters. The results of Tukey’s post hoc HSD test for metric and meristic variables, which showed significant differences between species in ANOVA, indicate that most metric traits and the number of scale rows above the lateral line differ significantly among the five morphotypes distinguished. Principal component analysis (PCA) and discriminant function analysis (DFA) effectively showed the morphometric variation between these morphotypes. The characteristics of body depth, head length, pectoral fin length, and caudal fin length are the most distinguishing diagnostic at the species level. We determined that the collected fish specimens represented: Lethrinus borbonicus Valenciennes, 1830, Lethrinus crocineus Smith, 1959, Lethrinus lentjan (Lacepède, 1802), Lethrinus microdon Valenciennes, 1830, and Lethrinus nebulosus (Forsskål, 1775). We also confirmed their validity as distinct species. Notably, L. crocineus, previously known only from the western Indian Ocean (Africa and Socotra), is now reported for the first time from the Persian Gulf and the Gulf of Oman. Lastly, a distribution map for the Lethrinus species is included.

Cryptic diversity of mudskipper genus Boleophthalmus (Gobiiformes: Oxudercidae) from the north coast of East Java, Indonesia

Abstract. Shabrina FN, Wibowo K, Arisuryanti T. 2024. Cryptic diversity of mudskipper genus Boleophthalmus (Gobiiformes: Oxudercidae) from the north coast of East Java, Indonesia. Biodiversitas 25: 412-420. Mudskippers of genus Boleophthalmus are commonly found in the Indo-Pacific area. This study aimed to examine the diversity of the genus Boleophthalmus from the north coast of East Java Province, Indonesia by employing the mitochondrial COI gene for DNA barcoding and morphological characterization. Ten individuals of this genus were analyzed. According to the similarity percentage evaluated using Basic Local Alignment Search Tool (BLAST) and Barcode of Life Data (BOLD) identification engines, all the individuals were identified as Boleophthalmus boddarti Pallas, 1770. However, phylogenetic analysis revealed that three of the individuals were identified as B. boddarti, and seven were identified as Boleophthalmus pectinirostris Linnaeus, 1758 originated from East Java, which is separated from the clade of B. pectinirostris from East Asia population. These results were supported by the genetic distance of 8.93%-13.81% and the morphological characteristics determined by principal component analysis (PCA). PCA revealed that B. boddarti and B. pectinirostris are primarily distinguished by the number of (longitudinal) scales (69-75 versus 113-123), length of second dorsal fin base (42.3-43.9 versus 38.1-49.0), and caudal fin length (18.1-22.4 versus 17.5-21.6). Further detailed studies are needed to clarify whether the seven individuals belonging to B. pectinirostris complex should be regarded as a new species or a new subspecies.

Confirmation of hilsa shad (Tenualosa ilisha) in Vietnamese waters: a morphological and genetic analysis

Abstract One specimen of tropical shad was caught from the Giang Thanh River, Kien Giang province, Vietnam in a survey on 16 October 2022. We identified the specimen as the hilsa shad, Tenualosa ilisha Hamilton, 1822 using morphological analysis, and further validated by its cytochrome oxidase subunit I (COI) sequence. The specimen was 418 mm long, 1428 g in weight, with a head length of 29.0% and pectoral fin length of 31.1% of its standard length. Notably, the presence of 34 scutes, a higher gill raker count and a caudal fin length within the moderate range for Tenualosa species distinguished it from T. macrura, T. toli and T. reevesii. The COI sequence of the sample matched closely to the T. ilisha. The results confirm that T. ilisha still endures Vietnamese water, where it was thought to be extinct. Climate change and Indo-Pacific Ocean currents may introduce expansion of distribution area of the T. ilisha. Further studies on distribution of the T. ilisha and other Tenualosa species and their dynamics are needed.

Intra- and interspecific variability in external morphology among three Symphodus species (Labridae)

ABSTRACT Labridae (wrasses) showcases a wide range of morphological variations, including diverse shapes, as well as a spectrum of ecological and behavioural characteristics. This study compared intra- and interspecific variation in three congeneric Symphodus species based on 19 morphometric characters associated with external morphology. Morphometric characters were commonly summed as the percentage of total length (TL%). The principal component analysis showed a clear separation of S. roissali from the other two Labridae species. The morphological distinction between species was statistically significant for all variables. While post-orbital length, anal fin length, caudal fin length and soft dorsal fin length are the hallmarks for Labridae species examined in this study, care should be taken when using other characters. Especially S. cinereus and S. ocellatus show similarities in many characters. S. roissali is distinguished from the other two species by its larger head and fin lengths (dorsal, anal, and pectoral). Intraspecific sexual dimorphism was significant for eight variables in the S. cinereus. No significant intraspecies morphological differences by sexes were observed for S. roissali and S. ocellatus species. Sex determination for these two species should be based on macroscopic examination of their gonads rather than external morphology.

Spatial Variability of Morphometric Characters of Freshwater Food Fishes from River Ganga of Districts, Kanpur, Prayagraj and Varanasi of Uttar Pradesh, India

The morphometric characters were evaluated to assess the population status of the commercial valuable food fishes collected from River Ganga at three different locations, Kanpur, Prayagraj and Varanasi. In this study, seventeen morphometric parameters were considered to examine during the month of October, 2022 to January, 2023. Usually, the various species of fishes consumed from the river Ganga. For present study, the morphometric characters like total length, fork length, standard length, pre-orbital length, post-orbital length, eye diameter, head length, pre-pectoral length, pre-dorsal length, pre-pelvic length, pre-anal length, length of dorsal fin, length of pectoral fin, length of caudal fin, length of caudal peduncle, body depth and body weight of four fish species, Labeo rohita, Rita rita, Wallago attu and Cyprinus carpio examined. A total of 25 specimens of each species were collected and the quantitative measurement of each aforesaid morphometric character provided crucial data regarding the development of fish body parts. Additionally, the positive correlations have been significantly (p < 0.01 and p < 0.05) detected amongst the selected morphometric characters of fishes. This study will be very crucial for fisheries management. Also, the findings will distribute the important standards for the geographical distribution of the commercially valuable food fishes. Further, the study defines that the growth of all fishes is suitable and the river Ganga ecosystem on three sites, Kanpur, Prayagraj and Varanasi is enormously favourable to the aquatic fauna especially fishes.

Allometric Growth Patterns and Ontogenetic Development during Early Larval Stages of Schizothorax waltoni Regan and Percocypris retrodorslis in Southwest China

Due to a sharp decline in resources, Schizothorax waltoni Regan and Percocypris retrodorslis have been listed as wildlife under second-class protection in China. Under culture conditions, the early development and allometric growth patterns of S. waltoni and P. retrodorslis were researched from the hatching stage to 60 DPHs (days post-hatching), and a sampling of ten to fifteen larvae was made every day, followed by measurements with Axio Vision 4.8 software (Carl Zeiss AG, Jena, Germany). Morphological indicators included the anal fin length, the body depth, the body depth at the anus level, the caudal fin length, the dorsal fin length, the eye diameter, the head length, the head depth, the pectoral fin length, the tail length, the trunk length, the snout length, the total length, and the ventral fin length. Based on the morphology development of S. waltoni Regan and P. retrodorslis, four periods of larval growth were identified: pre-flexion larvae at 0–14 DPHs and 0–16 DPHs; flexion larvae at 14–23 DPHs and 16–26 DPHs, post-flexion larvae at 23–50 DPHs and 26–52 DPHs, and the juvenile stage. In newly hatched larvae, most organs and body parts were not differentiated, and they successively developed within 26 DPHs. The depletion of the yolk sac was observed at 23 DPHs and 25 DPHs. Allometric growth mainly occurs in the head and tail regions, indicating that body parts related to feeding and swimming behaviors were more important than the other parts. In addition, the growth pattern shows that the development of organs gives priority to the functions of gill respiration, sensation, exogenous feeding, and swimming. The inflection points of body part growth patterns only appeared before 40 DAH, so future studies should concentrate focus on developing the best feeding from the first feeding to 40 DAH. These outcomes were discussed with regard to the ontogeny of the functional morphology in relation to ecology and aquaculture. It is expected that this research can provide valuable perspectives in species conservation.

Adaptive effects of parental and developmental environments on offspring survival, growth and phenotype

Abstract Phenotypic adjustments to environmental variation are particularly relevant to cope with putative environmental mismatches often imposed by natal dispersal. We used an intergenerational cross‐transplant field‐based experiment to evaluate the morphological and physiological effects of parental and postsettlement water flow environments on the orange‐fin anemonefish Amphiprion chrysopterus through ontogeny (at pre‐ and postsettlement stages). Offspring born from parents under high water flow had an 18% higher caudal fin aspect ratio (a compound measure of shape) at the presettlement stage, 10% slower growth after settlement, and 55% lower survival after settlement compared to offspring from low water flow parents. At the presettlement stage, caudal fin length was determined by parental caudal fin length. At the postsettlement stage, fish survived equally well with similar phenotypes in both high and low developmental flow environments. However, results suggest potential developmental phenotypic plasticity in caudal fin length, which increases more under low water flow during development. After settlement, growth was the only morphological or physiological trait that was associated with parental water flow, which was lower from parents under high flow, as was survival. These results give important insights into the parental contribution, both genetic and nongenetic, in determining early offspring phenotype and subsequent growth and survival. Our results also suggest that offspring may possess flexibility to cope with a wide range of local environments including those different from their parents. Overall, the findings of this study show the fitness consequences of living in different environments and the likely trade‐offs between parental and offspring fitness in a wild population. Read the free Plain Language Summary for this article on the Journal blog.

Effect of Mango Leaf Shoot Extract (Mangifera indica L.) on Zebrafish (Danio rerio) Cell Regeneration Induced by Hyperglicemia

Abstract. In many cases, diabetics often have difficulty in wound healing and lead to amputation. Hyperglycemia is an early symptom of diabetic which is characterized by high blood glucose levels. Cell regeneration is one of part by wound healing process. Mango plants have benefits as medicinal plants because they have secondary metabolites that can help heal wounds. The purpose of this study was to determine the effect of mango leaf shoot extract on blood glucose levels of zebrafish (Danio rerio) hyperglycemia due to alloxan and glucose induction and role of mango leaf shoot extract on zebrafish caudal fin regeneration. This study used an experimental method with 5 group treatments: control group, hyperglycemia, metformin 0,75 w/v, extract 10 µg/ml and extract 20 µg/ml. Parameters observed include blood glucose level, fin length and survival rate. Hyperglycemia was measured by blood glucose level, caudal fin regeneration was analayzed using fin length, also environmental factors and survival rate were measured. Result showed that mango leaf shoot extract 20 µg/ml was efective in reducing blood glucose levels, reaching 68,31% and aproaching metformin 0,75 w/v treatment with a decrease in blood glucose levels reaching 70,1%. Mango leaf shoot extract with concentration 20 µg/ml significantly different (p < 0,05) from hyperglycemia group and extract 10 µg/ml. Extract 20 µg/ml was effective in assisting the regeneration process with an increase caudal fin length reaching 0.94 cm during the treatment period.

Evaluation of breeding and growth performances of crossbreds and backcrossbreds with purebreds of Bangladeshi and Vietnamese climbing perch (Anabas testudineus)

AbstractThe present study aimed to improve the growth rate of the Bangladeshi native climbing perch (Anabas testudineus) through crossbreeding with Vietnam‐originated climbing perch, which is commercially cultured in Bangladesh. Therefore, crossbred between native and Vietnam strains of A. testudineus were evaluated in the first year (F1) as T1—Native ♀ × Native ♂, T2—Vietnam ♀ × Vietnam ♂, T3—Native ♀ × Vietnam ♂, and T4—Vietnam ♀ × Native ♂. In the second year (F2), backcrosses were performed between native and F1 generations as T5—Native ♀ × F1 (T3) ♂ and T6‐F1 (T3) ♀ × Native ♂ following five replicates in each treatment group. The F1 crossbreds of T4 were irregular in size with low survivability than T3, and therefore were not used as a parent in the second‐year backcross experiment. The breeding performances were reduced in the T4 (F1) and T6 (F2) compared to purebreds (T1 and T2). The specific growth rate (0.75%/day) of T5 and T6 was substantially lower than T3 and T4 but was considerably superior to the T1 and T2 purebred. The heterosis effect was highly evident in T6 (27.94%), whereas negative heterosis was determined in the crossbreds of the F1 generation (T4). Ten morphometric characteristics were compared and the caudal fin length, pectoral fin length, eye diameter, and body depth were responsible for the variation among T1–T6 groups by the second principal component. Furthermore, the results showed that the Bangladeshi native female climbing perch is linked with better breeding performances, and the Vietnam strain male is linked with better growth performance. Finally, the current breeding programme could enhance native climbing perch growth and survivability, which may have aquaculture potential and can be used through careful artificial selection on the commercial farm.

Sexual dimorphism in structures, size and shape of the cyprinid Nilgiri melon barb, Haludaria fasciata

Abstract The morphological differences between the sexes of a species is relevant to its captive breeding, ethology, and eco-biology and are studied extensively in fishes. In this paper, we analyzed the sexual dimorphism of the cyprinid Nilgiri melon barb, Haludaria fasciata (Jerdon), in their external structures, size, and shape. Physical examination, microscopical analysis, and morphometric and geometrical analyses of both sexes of the fish were conducted. The presence of tubercle pits and protuberant tubercles on the snout and orbital region were observed in males, while these were absent in females. Smaller-sized tubercles were arranged like a serration on the pectoral fin of males. Body size analysis indicated significant sexual size differences (P < 0.05) in body depth, fork length, eye diameter, pectoral fin length, and caudal fin length. Shape analysis indicated that the coordinate lengths L8 and L1 were the two that were significantly different (P < 0.05) between the sexes. In global redundancy trace analysis of vertices, the males in the population had more substantial variations in their shapes than did females. The paper discusses the possible functions linked with the dimorphic traits identified in H. fasciata.

Tissue regeneration effect of betulin via inhibition of ROS/MAPKs/NF-ĸB axis using zebrafish model

Betulin is the primary anti-inflammatory component of Betula platyphylla suk. cortex (birch bark), a time-honored Traditional Chinese Medicine (TCM) for healing trauma and tissue regeneration. However, the tissue regeneration effects and underlying molecular mechanism of betulin remain unknown. Therefore, it is necessary to investigate the wound repair effects and validate the mechanism of betulin in an appropriate model. In the present study, we evaluated the effects of tissue regeneration, melanin scavenging, and reactive oxygen species (ROS) inhibition of betulin using a zebrafish model. The mechanism of target genes and pathways were confirmed using quantitative polymerase chain reaction and western blotting in vivo, while molecular docking, absorption, distribution, metabolism, excretion, and toxicity investigations in-silico were conducted. Betulin significantly promoted the regeneration of zebrafish caudal fin length and area and alleviated melanin aggregation, as well as ROS generation. The relative mRNA expression of IL-1β, TNF-α, p38α, ERK1/2, and Caspase3, and the relative protein expression of p38α, ERK1/2, Caspase3, phosphorylated proteins of p-p38α, p-ERK1/2, and p-p65 were down-regulated following betulin administration. Meanwhile, the protein ratios of p-p38α/p38α, p-ERK/ERK, and p-p65/p65 were significantly decreased. In an in-silico study, binding affinities between betulin and P38α, ERK1, ERK2, and Caspase3, and the pharmacokinetic profile of betulin were predicted. The findings suggest that the tissue regeneration mechanism of betulin is based on the inhibition of excessive inflammatory responses, melanin aggregation, and the pro-apoptotic factor, Caspase3, during the proliferation phase via the ROS/MAPKs/NF-ĸB signaling axis. Our results suggest betulin as a potential candidate for tissue regeneration.

Exploratory stock identification through morphometric trait analysis of the estuarine round herring, Gilchristella aestuaria (Pisces: Clupeidae).

As a first step in stock identification of estuarine round herring Gilchristella aestuaria, a morphometric analysis of multiple standardised traits and body condition was conducted on samples from sites across the distribution range of the species, including freshwater and estuarine populations. Multivariate analyses, including a principal component analysis (PCA), revealed that sites on the same river system and sites in close geographic proximity tend to share morphometric traits. Most of the variation in PCA was due to caudal fin length (CFL). Single traits were analysed with generalised additive models with river system location as the smooth term. CFL was strongly related to river systems, and to a lesser extent salinity and turbidity. Unlike previous local-scale studies, this broad-scale study did not support the notion of ecotypes based on eye diameter. Condition indices like body depth and relative weight were related to climatic conditions, salinity and turbidity, more than to river system. The findings agree with previous studies on phylogenetic history and limited gene flow in G. aestuaria, and suggest variation in environmental productivity that affects body condition in different populations. Subsequent research should examine temporal changes in traits like CFL and body condition based on long-term seasonal sampling. Safeguarding this potential resource may be enabled by adopting appropriate management methods based on delineation of stocks with different levels of productivity and connectivity, before widespread fishing of this species is promoted.

Relationship between miR-203a inhibition and oil-induced toxicity in early life stage zebrafish (Danio rerio)

Dysregulation of microRNA (miRNA, miR) by environmental stressors influences the transcription of mRNA which may impair organism development and/or lead to adverse physiological outcomes. Early studies evaluating the effects of oil on developmental toxicity in early life stages of fish showed that reductions in expression of miR-203a were associated with enhanced expression of downstream mRNAs that predicted altered eye development, cardiovascular disease, and improper fin development. To better understand the effects of miR-203a inhibition as an outcome of oil-induced toxicity in early life stage (ELS) fish, embryonic zebrafish were injected with an miR-203a inhibitor or treated with 3.5 µM phenanthrene (Phe) as a positive control for morphological alterations of cardiovascular and eye development caused by oil. Embryos treated with Phe had diminished levels of miR-203a at 7 and 72 h after injection. Embryos treated with the miR-203a inhibitor and Phe exhibited a reduced heart rate by 48 h post fertilization (hpf), with an increased incidence of developmental deformities (including pericardial edema, altered eye development, and spinal deformities) and reduced caudal fin length by 72 hpf. There were significant reductions in lens and eye diameters in 120 hpf miR-203a-inhibitor and Phe-treated fish, as well as a significantly reduced number of eye saccades, determined by an optokinetic response (OKR) behavioral assay. The expression of vegfa, which is an important activator during neovascularization, was significantly upregulated in embryos receiving miR-203a inhibitor injections by 7 and 72 hpf with increased trends in vegfa expression in 72 hpf larvae treated with Phe. There were decreasing trends in crx, neurod1, and pde6h expression by 72 hpf in miR-203a inhibitor and Phe treatments, which are involved in photoreceptor function in developing eyes and regulated by miR-203a. These results suggest that an inhibition of miR-203a in ELS fish exhibits an oil-induced toxic response that is consistent with Phe treatment and specifically impacts retinal, cardiac, and fin development in ELS fish.

A new sisorid catfish of the genus Pseudolaguvia (Teleostei: Sisoridae) from Nagaland, north-eastern India.

Pseudolaguvia vespa, new species, is described from the Tscha River, Mokokchung district, Nagaland, India. The new species can be distinguished from congeners in having the following combination of characters: length of dorsal-fin spine 12.316.8% SL, a smooth anterior edge of the dorsal-fin spine, caudal peduncle depth 9.010.5% SL, body depth at anus 15.617.7% SL, caudal fin length 20.724.5% SL, pectoral fin length 20.124.1% SL, interorbital distance 22.728.1% SL, thoracic adhesive apparatus extending to midway between base of last pectoral-fin ray and pelvic-fin origin, and live specimens with two irregular, chrome-yellow bands on the body.

Multivariate morphometric study for species differentiation in two congeneric schizothoracids, Schizothorax niger Heckel 1838 and Schizothorax esocinus Heckel 1838 from River Jhelum Kashmir

Principal component and discriminant analyses were used to investigate morphological differences between Schizothorax niger Heckel 1838 and Schizothorax esocinus Heckel 1838 from River Jhelum, Kashmir, India. The purpose of this study was to identify the two species correctly and assign them into distinct genetic groups. Seven morphometric measurements (body weight, standard length, total length, head length, body depth, pre-dorsal length and caudal fin length) were studied in 100 fish specimens. All the studied morphometric characters reported higher mean values (p<0.01) in S. niger. The use of multivariant techniques such as principal component analysis, showed that the differences between the species resulted mainly from body weight, standard length, pre-dorsal length, head length, total length and caudal fin length. The stepwise discriminant analysis revealed that morphometric traits namely, standard length, pre-dorsal length and caudal fin length were the three most important variables to clearly distinguish the two species. Cross validation test using leave-one-out procedure indicated that 89% original grouped cases correctly classified into their groups, whereas 89% of cross validated grouped cases were correctly classified. Keywords: Fish stocks, Morphology, Schizothorax, Snow trout, Variation

Validity and redescription of the poorly known Japanese blenny Alticus orientalis Tomiyama 1955 (Perciformes: Blenniidae)

The poorly known blenny Alticus orientalis Tomiyama 1955 is considered a valid species and redescribed on the basis of 73 specimens (36 males and 37 females), 20.5–83.5 mm in standard length (SL). The species is characterized by the following combination of characters: dorsal-fin spines 14 (rarely 13); pectoral-fin rays 15 (very rarely 14 or 16); pelvic-fin rays I, 4; caudal-fin rays 12 (very rarely 11); supraorbital cirrus finely branched (except in specimens < ca. 20 mm SL); canine-like teeth absent on lower jaw; 1–9 small conical teeth on vomer (rarely secondarily lost); 3 (very rarely 2) pores in mandibular series; pre-anal-fin length 37.6–43.2 (mean 40.4) % SL in males, 39.9–46.9 (43.0) % SL in females; caudal-fin length 19.0–24.2 (21.8) % SL in males, 19.7–25.2 (22.4) % SL in females; pre-anal-fin length / caudal-fin length 1.6–2.2 (1.9) in males, 1.8–2.2 (1.9) in females; cheek without black spots; and head and pectoral fin without small black dots. Although A. orientalis is most similar to Alticus montanoi (Sauvage 1880) [all Japanese specimens previously identified as Alticus saliens (Lacepede 1800) are actually this species], it can be distinguished from the latter by the presence of teeth on the vomer, a greater number of pores in the mandibular series, greater pre-anal-fin length, and slightly shorter caudal-fin length. In addition, genetic analysis supports the divergence of A. orientalis from available sequences from other species of Alticus. In Japanese waters, A. orientalis is distributed around (and probably endemic to) the Izu and Ogasawara islands, whereas A. montanoi is distributed in the Ryukyu and Daito islands.

Re-description of the loach species Leptobotia citrauratea (Teleostei, Botiidae), with the description of L. brachycephala from southern Zhejiang Province, China.

Leptobotia citrauratea (Nichols, 1925), a loach species, originally described from Dongting Lake, was recently rehabilitated, based on the examination of the holotype and non-topotypical specimens. Several field surveys conducted from 2016 to 2019 in Zhejiang, Jiangxi and Hunan Provinces, P.R. China, yielded many specimens of Leptobotia which were initially identified as L. citrauratea. Molecular and morphological analyses of these specimens demonstrated that two distinct species are involved. One was identified as L. citrauratea, represented by specimens from both the Poyang and Dongting Lake (type locality) systems in Jiangxi and Hunan Provinces, and the other species is described as L. brachycephala, represented by specimens from the Ou-Jiang and Qu-Jiang, two coastal rivers of Zhejiang Province, China. Leptobotia brachycephala resembles L. citrauratea and L. micra in having a row of orange dots or an orange stripe along the dorsal mid-line of the body, extending from the nape to the caudal-fin base – a unique character in Leptobotia. Leptobotia brachycephala differs from L. citrauratea and L. micra Bohlen & Šlechtová, 2017, in caudal-fin shape and pelvic-fin insertion and proportional measurements including caudal-fin length, head length, predorsal length and anal-fin length. Its species status was further corroborated by position in a molecular phylogenetic analysis, based on the mitochondrial cyt b gene and its minimum uncorrected p-distance (2.9%) from congeneric species.

Morphological diversity of the Caspian Asp, Leuciscus aspius, in the South Caspian Sea basin (Osteichthyes: Cyprinidae)

To study the intraspecific diversity of the Caspian Asp, Leuciscus aspius in the South Caspian Sea region, Iran, we collected in 2016–2017 a total of 101 specimens from Aras River and Astara, Anzali, Kiashahr and Langeroud shores, and analysed 41 morphometric and nine meristic characteristics with multivariate statistical methods. Significant differences were found between these populations in 27 morphometric traits. A Principal Component Analysis (PCA) showed that the upper caudal-fin length and the maximum body depth are effective characters along the PC1 and PC2 axis, and based on MONOVA/CVA, the differences between the studied populations are significant (P<0.01). Morphometric characters were more powerful than meristic characters in distinguishing L. aspius populations. It is discussed whether differences in habitats and spawning grounds affect morphological traits.

Stock structure delineation of an endangered mahseer, Tor putitora (Teleostei: Cyprinidae) from two Indian rivers by morphological and meristic attributes

An understanding of the stock is a basic requirement for the management of the fishery resources. The endangered mahseer, Tor putitora (Hamilton, 1822) is a commercially important fish distributed extensively in the foothills of Himalayas. Box plots and multivariate statistical tools like Principal Component Analysis (PCA) and Discriminant Function Analysis (DFA) were used to delineate the stocks of T. putitora from two Indian rivers, Yamuna and Satluj using 6 meristic and 24 morphometric characteristics. A comparison of the morphometric and meristic characters using box plots revealed variations in eye diameter (ED), length of rostral barbel (LRB), standard length (SL), pre-anal distance (PAD), distance between pectoral and pelvic fin (DPP), distance between pelvic and anal fin (DPA), length of dorsal fin (LDF), length of pectoral fin (LpecF), length of pelvic fin (LpecF) and length of caudal fin (LCF) for distinguishing populations from these two rivers. Upon PCA, the first three principal components accounted for 69.66% of total variance in head parameters whereas for total length, the first 5 principal components accounted for 73.23% of total variance. For meristic characters, the first two PCs explained 75.65% of the total variance. The step-wise DFA retained only one function for morphometric as well as meristic characters explaining 100% of the variance. The Wilks’ lambda tests for morphometric and meristic data indicated differences between the populations of T. putitora from both the rivers.