Fin Ray Counts Research Articles

First record of Croaking Gourami Trichopsis vittata (Cuvier, 1831) from West Bengal, India

The Croaking Gourami Trichopsis vittata (Cuvier, 1831) is a native fish to southeastern Asia and Sundaland, with introduction reports from the USA, Philippines, and many other countries including India. In India, this species was first reported from Chembarampakkam Lake situated in Chennai during the year 2015. This study reports the presence of this fish for the first time in the Magra Beel, a wetland in the district of Nadia, West Bengal, in 2021, 2022, 2023. The laboratory evaluated the fish samples taken from the marsh to determine their fin ray counts and morphometric data. The results identified the species as T. vittata and supported previous research.

Redescription of Hyphessobrycon cachimbensis (Characiformes: Characidae) with the description of a new congener from the Serra do Cachimbo, Brazil

Abstract The Serra do Cachimbo is a highland area at the southeastern portion of the Amazon Forest drained by the headwaters of tributaries of rios Xingu and Tapajós. It is known as an area of high level of endemism of fish, low species diversity, and very few taxa with broad distribution in the other parts of the Amazon. Despite its biogeographical importance, there are still many poorly sampled areas. Four expeditions to the region yielded in the rediscovery of a poorly known, endemic species, Hyphessobrycon cachimbensis, and the discovery of a similar, allopatric undescribed congener, frequently misidentified as H. cachimbensis. We provided the redescription of H. cachimbensis and the description of the new species. Both can be differentiated from most congeners by having a conspicuous longitudinal dark stripe on body and anal-fin base convex in males, due to thicker musculature insertion in the region. Other diagnostic features are mostly related to counts of scales and fin rays.

A revision of the gudgeon genus Hypseleotris (Gobiiformes: Gobioidei: Eleotridae) of northwest Australia, describing three new species and synonymizing the genus Kimberleyeleotris.

Species within the northwest Australian clade of Hypseleotris (six species) and the genus Kimberleyeleotris (two species) are reviewed following the recording of new populations in the region and a molecular study of the group that identified three undescribed candidate species. Based on the analysis of extensive morphological and nuclear and mitochondrial molecular datasets, Kimberleyeleotris is here formally synonymised with Hypseleotris. Furthermore, three species from the Kimberley region, Western Australia, are described to science: Hypseleotris maranda sp. nov., Hypseleotris wunduwala sp. nov., and Hypseleotris garawudjirri sp. nov. The presence of, or number of scales across the head and body, the pattern of sensory papillae on the head, fin ray counts, dorsal and anal fin colouration (particularly in breeding males), and body depth, can be used to distinguish the members of the northwest Australia lineage. Furthermore, the newly described species were genetically separated from all northwest Australian congeners by K2P distances ranging from 7.8-11.3% based on the CO1 gene, and 7.7-16.3 % based on the entire mitochondrial genome. Two of the new species, H. maranda sp. nov. and H. wunduwala sp. nov., have extremely narrow ranges being found in single sub-catchments of the Roe and King Edward Rivers respectively. On the other hand, H. garawudjirri sp. nov. is moderately widespread, being found across the Charnley, Calder, and Sale rivers. While the conservation risk to H. maranda sp. nov. and H. wunduwala sp. nov. is inherently high due to their small range, there are currently no obvious local threatening processes to either of these species given their remote locations that are little impacted by human activities.

Geometric morphometric analysis and meristic variations of Philippine populations of the crescent perch Terapon jarbua (Centrarchiformes: Terapontidae)

The crescent perch Terapon jarbua is a demersal and catadromous fish that is widespread in the Indo-West Pacific region. It is a commercially important species in the Philippines and other Asian countries. Morphological differentiation among populations of T. jarbua throughout Philippine waters was investigated using morphometric and meristic characters. A total of 609 crescent perch (428 male, 181 female) were collected from nine localities in the Philippines. Meristic analyses showed the highest significant differences among populations in the lateral line scale and gill raker counts. Morphometric analyses revealed significant differences in shape among the nine T. jarbua populations. Allometry was found to be independent of size differences. Morphological differences were detected in the head, lip, and caudal peduncle regions. Specimens from General Santos City and Navotas were the most morphologically distinct from each other, whereas specimens from Sariaya and Balayan had the most similar shape. These can be attributed to the latitudinal gradient of the localities. Sexual dimorphism was also detected as significant differences were found in the specimens' lip positions, anal fin spine positions, caudal peduncle width, lateral line scale counts, gill raker counts, and pectoral fin ray counts. These morphological and meristic variations could be attributed to differences in feeding habits because T. jarbua is an omnivorous fish with a broad diet and can be found across marine, freshwater, and brackish environments. Further investigation of its diversity is recommended through the evaluation of T. jarbua feeding habits and their habitat's physicochemical characteristics. Additional sampling of populations outside of the Philippines is also recommended.

Morphological Characteristics and Reproductive Organs Assessment of Blue-Spotted Mudskipper Boleophthalmus Boddarti in Peninsular Malaysia

Mudskippers have a unique adaptation allowing them to live on the land and commonly inhabiting the mangrove ecosystem. A fundamental study on the Blue-spotted mudskippers, Boleopthalamus boddarti were purposely to identify the species through morphometric and meristic characteristics, observation on the gonad organs as well as to correlate with their length-weight relationship. Collection of B. boddarti (n=72) from Matang Perak, Pendas Johor and Pekan Pahang was conducted using hand and net. Data collection on seventeen morphometric and seven meristics characters, length and weight, and pictorial documentation on male and female gonads were conducted. The means of each characteristic were estimated by using analysis of Variance (ANOVA) with P<0.05. The morphometric analysis found eye diameter and posterior dorsal fin ray count characteristics were significantly different (P<0.05) followed by five meristics characteristics except for anterior dorsal fin ray count and upper jaw teeth characteristics (F value ≥ 1.0). The mature gonad of female B. boddarti was found with an ovary in bright yellow coloration, turgid, firm and visible presence of eggs. Male gonads were identified with a testis having two lobes, a swollen structure at the top of the elongated shape and appear pale pink and thicker than the immature testes that generally exist in string-like structures. The length and weight of the fish were found directly proportional to the regression curve displayed b≠3. Morphometric and meristic characteristics were a reliable method in the identification of fish in general and for B. boddarti in specific. The observation of gonads differentiation helps understand the mature and immature state of the sex organs. This study offered an easy, quick and low-cost approach in determining species and sexes compared to the molecular method.

Northern Sunfish (Lepomis peltastes) Distribution in Illinois

The recent elevation of Lepomis peltastes (Northern Sunfish) as a separate species from L. megalotis (Longear Sunfish) has resulted in an incomplete understanding of the species' distribution in Illinois, as most occurrence records cannot differentiate the 2 species. We evaluated Northern Sunfish and Longear Sunfish specimens to identify morphological characteristics that could differentiate the 2 species; relative body depth, relative opercular flap length, and pectoral fin ray count were most useful. We reevaluated 867 Longear Sunfish specimens from the Illinois Natural History Survey Fish Collection and identified 103 as Northern Sunfish. Based on distribution of these specimens, it is probable that Northern Sunfish occur in 14 basins in the eastern half of Illinois, a range that extends farther south than was previously estimated.

Larval study revealed diversity and life-history traits of crypto-benthic eel gobies.

Because adult and juvenile eel gobies usually hide within the burrows of muddy substrates, their diversity and life history have not yet been fully elucidated. We investigated larval specimens of the eel gobies collected on Okinawa Island in southern Japan. The genus Trypauchenopsis was previously thought to consist of only one species, but our larval collection identified two species, Trypauchenopsis limicola and Trypauchenopsis intermedia, distinguished by their species-specific melanophore arrangements and differences in their fin-ray counts. Taenioides kentalleni were previously known from only two specimens worldwide. A third specimen of this species has now been added from the larval collection. In addition to the three species above, Taenioides gracilis and Caragobius urolepis were identified and the larval morphologies of the five species were described for the first time. All the larvae collected in the present study were at late postflexion stage. T. limicola, T. intermedia and T. gracilis were presumably collected in the estuaries and beaches when approaching their adult habitats at the end of pelagic life. They were 8.5-10.3 mm in standard length, and otolith analysis suggests that their pelagic larval durations are a little longer than 1month (average 34-37 days). The larval occurrence suggested that the spawning season of T. limicola is May-December, when the water temperature is warmer than approximately 20°C. Our work reveals that studying the larval stage can provide new information on the taxonomy and life history of the elusive cryptobenthic fish.

A new species of gobiid fish Lentipes niasensis (Gobiidae: Sicydiinae) from Nias Island, Indonesia

A new species of goby of the subfamily Sicydiinae, Lentipes niasensis, is described from the stream of Humogo River, Nias Island, Indonesia. This species can be distinguished from all congeners by the following combination of features: (1) fin ray counts: D2 I/10; A I/10; P 17-18; D1 not connected to D2 in either sex. (2) squamation: LR 7-11; anterior half of body naked, lateral body scales present from 5-6th rays of second dorsal-fin to hypural, embedded in skin. (3) upper jaw teeth in male 14-19 and in female 33-38. (4) urogenital papilla in male slender and distally pointed, flanked by pair of associated fleshy lobes and not retractable into sheath-like groove. (5) distinctive colour pattern of male: upper lip greyish, red patches on the pectoral-fin base, on mid-body below origin of second dorsal-fin and at caudal peduncle.

Caudal Skeleton Variations in Alburnoides Fish Species from Iranian Water Basins

The species in the genus Alburnoides is distinguished based on having a combination of some morphological characteristics and different fin ray counts. Most descriptions are based on morphological characteristics and molecular approaches. The species are widely distributed in the Iranian basins. Since osteological structures of fishes provide major biological and ecological information, studying these structures is valuable. The present study was conducted to provide a caudal skeleton variations in Alburnoides fish species from Iran for the first time. For this purpose, three specimens of Alburnoides species were collected from different basins using the gill net (1mm) and electrofishing device and fixed in 10% buffered formalin. Then, the specimens were cleared and stained with alcian blue and alizarin red for osteological examination. Based on the results, several differences were observed among the species. The caudal shape comparison of Alburnoides species from the Inland water of Iran revealed some differences among them including the shape of the epural and rudimentary neural arch. However, ten species of Alburnoides, from Iran were not distinguishable based on these osteological characteristics.

Two new cryptic species of the freshwater fish genus Gobiomorphus (Gobiiformes: Gobioidei: Eleotridae) in New Zealand

ABSTRACT We describe two new species in the genus Gobiomorphus, a radiation of fresh and brackish water gudgeons known from Australia and New Zealand. These species are a prominent component of New Zealand’s freshwater ichthyofauna and most are widely distributed throughout both the North and South Islands. Two of the inland species, G. breviceps and G. basalis, are composed of disjunct northern and southern populations that are distinguishable with molecular data. We examine individuals from across the ranges of both species, identify morphological differences between them, and describe two new species: Gobiomorphus dinae n. sp. (distinct from G. basalis) and Gobiomorphus mataraerore n. sp. (distinct from G. breviceps). Although the species are similar, they vary in dorsal spine count (G. dinae) and pectoral fin ray count (G. mataraerore). We provide mitochondrial COI sequences for each species pair to facilitate identifications by DNA barcoding. These species represent examples of divergence in allopatry, with diagnostic characters arising over the last 2−5 million years in the G. breviceps/G. mataraerore pair, and fewer than 2 million years in the G. basalis/G. dinae pair. We also designate a lectotype for G. basalis (the paralectotype is G. cotidianus) in order to clarify confusion surrounding the original syntypes.

Two new species of Rhinogobius (Gobiiformes: Oxudercidae) from Palawan, Philippines, with their phylogenetic placement

Two new species of Rhinogobius found in streams on central part of Palawan Island, Philippines are described. The two new species, Rhinogobius estrellae and Rhinogobius tandikan share unique transverse rows of sensory papillae on the cheek with Rhinogobius similis Gill, 1859, but differ from the latter in fin ray counts, arrangement of the scales, etc. The two new species are distinguished from each other by the pectoral-fin ray count, the longitudinal- and predorsal-scale counts, and colouration of the body. Rhinogobius estrellae new species and R. tandikan new species have been found allopatrically in a stream within Malatgao River system flowing into the Sulu Sea and in the Cayulo River flowing into the South China Sea, respectively. The Malatgao River system is the southernmost habitat of the genus Rhinogobius. Rhinogobius similis had been considered as the only member of the most basal lineage of this genus, but our mitochondrial genome analysis suggested that the two new species are additional members of this lineage. They are considered to be relicts of their common ancestor with R. similis, which probably had a wider distribution.

Türkiye'nin Akdeniz Kıyılarında Nadir Görülen Echeneis naucrates'in Son Kaydı

One specimen of live sharksucker was caught with a bottom trammel net in Taşucu Bay, south-eastern coast of Turkey, at 1 m depth on May, 2021. Meristic parameters were determined by fin ray counts and metric parameters were measured from the photos of the specimen. Excluding the recent record in Antalya Gulf, previous records of this species occurred later than May, generally in July in the Mediterranean Sea as well as in the Aegean Sea. The biometrical measurements were different in Taşucu Bay compared to those caught from the Aegean Sea and the central Mediterranean Sea (Tunisian and Sicilian waters), but relatively similar to those reported from Croatia. Major discriminative variables, albeit less significant in individuals from the central Mediterranean, were the number of anal, pectoral and dorsal fin rays. Numbers of suction disc laminae were higher in individuals from the central Mediterranean Sea and New Zealand than those from the Turkish coasts (all 21 disc laminae). The statistical analyses (Principal Component and Discriminant analyses) affirmed successful use of meristic parameters to differentiate the biometric characteristics of the species from the Aegean Sea, the central and eastern Mediterranean Sea. The length-weight relationship showed that the species had a negative allometric growth.

Three New Small Snailfishes of the Genus Careproctus (Teleostei: Cottiformes: Liparidae) from the Aleutian Islands, Alaska

Three new species of small snailfishes, with maximum lengths up to only 60 mm, are described from collections in the Aleutian Islands taken during fisheries resource assessment surveys conducted by the U.S. National Marine Fisheries Service. Previous molecular analyses demonstrated that two of the species are closely related; the third species was found among material thought to consist only of one of these two species. Two of the new species are distinguished from all other species of Careproctus on the basis of an anterior dorsal-fin lobe with exserted rays and bodies with widespread small rounded bumps covered with tiny prickles. They are distinguished from each other on the basis of fin ray and vertebral counts, as well as differences in body shape. The third new species is diagnosed from all other species of Careproctus by having a small teardrop-shaped body, with loose thin skin and without an anterior dorsal-fin lobe, as well as by high counts of meristic characters, especially pectoral-fin rays. Each species is found widely within the Aleutian Islands from west of Kiska Island in the west to north of Umnak Island in the east at depths of 90 to 447 m.

The Hooghly croaker, Panna heterolepis Trewavas, 1977: Identification through morphometric and meristic characteristics

As morphometric information for Hooghly croaker Panna heterolepis Trewavas, 1977 is absent in the most extensively accessed and world’s largest online database for fishes (FishBase); this study was undertaken to provide the complete informative description on morphometric relationships and meristic counts of various fin rays. A total of 200 individuals were sampled from the Bay of Bengal (Bangladesh) during July 2018 to June 2019, using several traditional fishing gears. Meristic counts were computed using a magnifying glass. Body weight (BW) and several length measurements were taken through an electronic balance and digital slide calipers for each individual. LWRs (Length-weight relationships) were calculated as: W = a×L b . All LWRs and LLRs (length-length relationships) were found significant with r 2 ≥ 0.919 ( p < 0.0001) and 0.928 ( p < 0.001), respectively. BW vs. TL and TL vs. SL were the best fitted models for LWRs and LLRs, respectively. Fin formula was: dorsal, D. 43–55 (VIII–X+i/34–44); pectoral, P. 15-17 (i/14–16); pelvic, Pv. 6 (I/5); anal, A. 7–10 (II/5–8); and caudal, C. 17–19 (ii/15–17). These results will a) make a vital contribution for species identification in the marine and coastal waters of Bangladesh and adjoining countries, and b) provide information for Fish Base.

Morphological differentiation in African catfish (Clarias gariepinus) from three different populations in Nigeria

AbstractIntraspecific morphological variation in Clarias gariepinus was studied in three water bodies. Twenty-three morphometric characteristics and seven meristic were used. Principal component (PC) analysis showed that morphometric traits of River Osun and Ogbese were somewhat related while that of Aago showed no relatedness, there were no difference among the meristic counts of the populations. PC1, and PC2 accounted for 93% and 4% of the variation observed in the populations. High positive correlation was observed in Aago (r = 0.872, b = 2.10) and Ogbese population while low correlation and negative allometric growth (r = 0.425 and b= 1.38) was observed in Asejire population. Cluster analysis revealed that three studied populations are separated into two major clusters, with samples from Asejire and Ogbese population found within the same cluster but different sub- clusters, similarly some of samples from Aago were also within the same cluster while samples 10 were found on a separate and major cluster. The study confirms the variability among individual species within each population, indicates the presence of genetic diversity among the populations of C. gariepinus and the Pre-anal distance and dorsal fin ray count could be employed in the identification of populations of catfish.
 Key words: morphometric traits, meristic characters, populations, allometric

Comparative morphology of freshwater sculpin inhabiting different environmental conditions in the Chesapeake Bay headwaters

We compared body morphology of two freshwater sculpin taxa that inhabit distinct environmental conditions in the Chesapeake Bay watershed of eastern North America: Potomac sculpin (C. girardi, Robins; PS) and checkered sculpin (C. sp. cf. girardi; CS). Both taxa are endemic to the study area, but PS are more broadly distributed than CS which are limited to karst groundwater-dominated streams in the central Potomac River basin. We examined preserved specimens from sites encompassing their geographic range (six sites per taxon) to evaluate taxonomic differences and environmental effects. Pelvic fin ray counts and body shape distinguished the study taxa. Morphological variation exhibited stronger relationships to environmental covariates (site elevation and basin size) in PS than CS as expected. In addition, the frequency of specimens with a united median chin pore increased with site elevation in PS (but not CS), suggesting thermal effects on preoperculomanibular canal development. However, contrary to expectation, PS did not exhibit greater among-population variation in body shape than CS, and this indicates the potential importance of unmeasured environmental differences among karst groundwater-dominated streams in the study area. Our study also indicated the utility of stream-level management units for CS, an undescribed species recognized as “critically imperiled” by state agencies.

Revision of the diagnostic characters of two morphologically similar snook species, Centropomus viridis and C. nigrescens (Carangiformes: Centropomidae).

Historically, the taxonomic identification of the two snook species, Centropomus viridis and C. nigrescens, has been challenging due to their morphological similarity and the inconsistency of the characters used for diagnosis. Therefore, this study aimed to evaluate the usefulness of the morphologic, meristic, and morphometric characters currently being used to identify C. viridis and C. nigrescens, based on molecular data. The results showed that the gas-bladder shape (i.e., C. viridis with diverticula and C. nigrescens without diverticula) was the only morphological character univocally related to genetic identification. Likewise, geometric morphometrics separated two groups; each corresponds to only one of two genetically (and gas bladder shape) identified species. Of all the meristic characters examined, only the second dorsal fin ray count (nine for C. viridis and ten for C. nigrescens) was related to the gas bladder shape and genetic identity; therefore, it is the only external character with a diagnostic utility to separate each species.

Morphometric and Meristic Analysis of Tor putitora (Hamilton Buchanan) from Ujh River, Kathua (J&K)

The morphology of fishes has been the major source of information for taxonomic and evolutionary studies. The present communication deals with the taxonomic analysis of Golden Mahseer- Tor putitora, collected from river Ujh, a tributary of Ravi in District Kathua, (Jammu & Kashmir). The morphological characters are generally divided into two major categories, the morphometric and the meristic. For morphometric studies the parameters considered were: the total length, standard length, head length, pre-dorsal length, pre-ventral length, pre-anal length, caudal length, snout length, eye diameter and maximum body depth. The growth of parameters were studied in relation to three independent variables, i.e., total length, standard length and the head length. Meristic counts of fin rays and fin spines etc. were also studied.

A new species of Characidium (Characiformes: Crenuchidae) from the Chapada dos Veadeiros, Goiás, Brazil

Abstract A new species of Characidium is described from the tributaries of the rio Tocantinzinho, rio Tocantins basin, located in the southern portion of the Chapada dos Veadeiros, at about 1,200 meters of elevation, Goiás, Brazil. The new species can be diagnosed by an unusual combination of two apomorphic features present in distinct clades of Characidium, the presence of a scaleless isthmus in allied to with a single row of dentary teeth. Additionally, the new species has a unique color pattern of inconspicuous vertical bars disconnected from the dorsal midline, forming seven to nine square blotches along body sides, and the presence of a dark saddle-shaped mark at the dorsal-fin base. Osteologically, it can be diagnosed by having the first and second anal-fin proximal radials fused and contacting the third hemal spine, which is branched. The new species also has a peculiar, unusual variation of fin-ray counts among its congeners.

Hidden or unnoticed? Multiple lines of evidence support the recognition of a new species of Pseudocorynopoma (Characidae: Corynopomini).

Species delimitation is a permanent issue in systematics. The increasing recognition of geographically isolated populations as independent lineages allowed by new methods of analysis has inflated the species-populations dilemma, which involves deciding whether to consider separate lineages as different species or structured genetic populations. This is commonly observed between fishes of adjacent river basins, with some lineages being considered allopatric sister species and others considered isolated populations or variants of the same species. Pseudocorynopoma doriae is a characid diagnosed from its single congener by the number of anal-fin rays and sexually dimorphic characters of males, including distinct fin colouration. The authors found variation in the colour pattern between isolated populations previously identified as P. doriae but no variation in scale or fin-ray counts. They analysed molecular evidence at the population level and morphological differences related to life history (e.g., colour dimorphism related to inseminating behaviour). The results provide compelling evidence for the recognition of a new species of Pseudocorynopoma despite the lack of discrete differences in meristic data. The recognition of the new species is consistent with biogeographical evidence for the long-term isolation of the respective river drainages and with differences between the ichthyofaunal communities of these rivers.