Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 54(2), 187-194, 2019 Short Communication They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. Sexual dimorphism of Canthophrys gongota (Teleostei: Cobitidae) using A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric landmark-based geometric morphometrics in the Atrai river of Bangladesh males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism M. M. Akter, M. G. Azom, M. S. Reza Sabuz, M. H. Islam and M. R. Islam* 2 stickleback (Gasterosteus aculeatus), Copeia, pp caught fishes by using fine meshed seine net (15 × 3.5 m , and 4). In contrast, males had thin and slightly pointed AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity abdominal shape as a reproductive structure of mature fishes for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and may be due to genetical, environmental or their combinations 336-349. mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) pectoral and pelvic fins compared to the females. Besides, Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) Department of Fisheries Biology and Genetics, Faculty of Fisheries, Hajee Mohammad Danesh Science and Technology would be expected to change during spawning season Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, University, Dinajpur-5200, Bangladesh Department of Fisheries Biology and Genetics under Hajee cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, the rough surface while males carried whitish colored smooth illustrate and quantify the structural variations of animal taxa points that cluster together had similar shapes but far uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low capoeta gracilis) (Pisces: Cyprinidae) in the Tajan dimorphism in body shapes of the spotted barb fish, stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body removed showed different shapes (Fig. 6). A discriminant River (Iran), Hydrobiologia 673: 41-52. Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, Abstract using a more significant approach (Adams et al., 2004; Slice, (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main Puntius binotatus of Lake Buluan in Mindanao, Santos BS and Quilang JP (2012), Geometric morphometric weight) and distances between bases of paired (pectoral and function analysis (DFA) was used to judge distinctions 2011,03161,x 2007). Now, it is widely applied to study the sexual species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. analysis of Arius manillensis and Arius dispar Identification and measurement of specimens pelvic) and unpaired (anal and caudal) fins were significantly between males and females of C. gongota where the group Studies on sexual dimorphism of gongota Loach Canthophrys gongota (Local name: Pahari Gutum) dimorphism and ontogeny in fishes (Kitano et al., 2012) between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, varied (F > 5.62, P 0.01) while no statistical divergences (F was correctly classified as 97.66% (F = 7.01, P 0.01). The Echeverria TW (1986), Sexual dimorphism in four species of was performed capturing them from the Atrai River of Dinajpur district in Bangladesh. Females had including their intraspecific phenotypic differences. Even At first, external form and/or ornamentation of the collected was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. < 1.14, P > 0.05) were observed in the lengths of dorsal, low overlap and high spread of DFA values explained higher rockfish genus Sebastes (Scorpaenidae), light blotches and patches with thick and rounded pectoral and pelvic fins while males having dark though sexual distinctions between males and females have specimens were examined to find out any traits as reliable abdomen than those of males may be due to larger gonads and minimal variation on the tail between males and females Cobitoidei), Raffles Bulletin of Zoology Supplement pectoral, pelvic and˂ caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Environmental Biology of Fishes 15: 181-190, Saurabh S, Sridhar N, Barlya G, Hemaprasanth, blotches and patches with thin and comparatively pointed paired fins. Body size, lengths of the anal been studied on some loaches (Bohlen, 2008; Plongsesthee et indicators in their body followed by Plongsesthee et al. demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota (2015), Landmark based geometric morphometric 26: 1-199. (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P fin and distances between the bases of pectoral, pelvic and caudal fins were significantly different al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that analysis on body shape variation of Mesopristes Eros T (2003), The reproductive characteristics of a spined B RW (36.22%), RW (24.42 %), RW (9.38%), RW (6.87%), Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua (5.62 < F < 11.65, P 0.05) between the sexes of C. gongota. The expansion factors of mean hypothesis is that there is no significant variations between individual was measured with a digital balance (HD-602ND, 1 2 3 4 more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes cancellatus (Cuvier, 1829), Advanced Environmental loach population (Osteichthyes, Cobitidae) based on RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. thin-plate grids and vectors also showed that the head region of males was statistically different from two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. ˂ variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat females, whereas abdomen and tail of the females were considerably broader than those of the males. assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, Both PCA (principal component analysis) and DFA (discriminant function analysis) plots showed identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. Received: 19 April 2018 morphologically little overlapping of landmark points which discriminated the females from the to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora other RW scores. The first two relative warps accounted for 111: 977-1016. Revised: 06 June 20180 males. These findings are the first records on the sexual dimorphism of this rare species that would against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, 60.64% of total variance in 24 landmark points. Positioning Accepted: 03 December 2018 be baseline in a future study. species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. Keywords: Paired fins; Head regions; Landmarks; Gongota loach; Atrai River of Anthropology 36: 261-281. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire Introduction most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. University Press, p 466. Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, Talwar PK and Jhingran AG (1991), Inland fishes of India Sexual dimorphism is the systematic variation in form and/or information present on these aspects for loaches (Bohlen, ę Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral there were no significant variations in the lengths of pectoral, Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New color between the sexes of animal taxa. Fishes display their 2008). The key sexual dimorphic traits are commonly used However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. sexual dimorphic traits in body size, shape, fins, and/or species are important tools for fish stock assessment. The for identification and taxonomy of loach fishes but also which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on Solea lascaris (Risso, 1810) along the Portugal coast, landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of ornamentation (Echeverria, 1986). Morphological variations have been applied to classify genera and subgenera (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the between sexes are not only found in primary sexual (Nalbant, 1994). was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: characters, but also in secondary sexual traits not directly Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. associated with their spawning (Kitano et al., 2007). Some In Bangladesh, a total of 265 species of freshwater fishes is greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the fishes exhibit temporary sexual characteristics (e.g. colors) recorded where at least 24 species of loaches belonging to 10 During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: but others show permanent (e.g., Clasper organ) structures genera of three families (Rahman, 2005). The Atrai River is observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, (Saurabh et al., 2013). However, many fishes do not show one of the major rivers in Dinajpur district of Bangladesh variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of any sexual disparities during their life cycle (Chu-Koo et al., (Islam and Mia, 2016; Islam et al., 2017; Islam et al., 2018) 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. 2009). Sexual dimorphism of fishes can be determined by the compared the mean of ranked dissimilarities between groups˂ enriched with five species of freshwater loaches (Chaki et al., and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra surveillance of fish gonads by dissecting the individuals to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric 2015). The gongota loach, Canthophrys gongota (Hamilton, dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. regardless of maturity and breeding season. In fishes, some was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color 1822) under the family Cobitidae locally known as ‘Pahari loaches (exceptč three species of Cobitis reported by morphological traits differ between sexes apparently playing between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 Gutum’ are found in swamps, lakes and rivers of Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. vital roles in their spawning period (Plongsesthee et al, (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive Mymensingh, Sylhet, Dinajpur and Rangpur districts of 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries 2012). Although sexual behaviors are the most crucial facts of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a in reproduction and autecology of fishes but no available Bangladesh (Talwar and Jhingran, 1991). distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112. *Corresponding author e-mail: [email protected] 188 Sexual dimorphism of Canthophrys gongota 54(2) 2019

They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism 2 stickleback (Gasterosteus aculeatus), Copeia, pp caught fishes by using fine meshed seine net (15 × 3.5 m , and 4). In contrast, males had thin and slightly pointed for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity abdominal shape as a reproductive structure of mature fishes may be due to genetical, environmental or their combinations 336-349. would be expected to change during spawning season mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) pectoral and pelvic fins compared to the females. Besides, Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, Department of Fisheries Biology and Genetics under Hajee cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, the rough surface while males carried whitish colored smooth illustrate and quantify the structural variations of animal taxa points that cluster together had similar shapes but far uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low capoeta gracilis) (Pisces: Cyprinidae) in the Tajan dimorphism in body shapes of the spotted barb fish, stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body removed showed different shapes (Fig. 6). A discriminant River (Iran), Hydrobiologia 673: 41-52. Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, using a more significant approach (Adams et al., 2004; Slice, (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main Puntius binotatus of Lake Buluan in Mindanao, Santos BS and Quilang JP (2012), Geometric morphometric weight) and distances between bases of paired (pectoral and function analysis (DFA) was used to judge distinctions 2011,03161,x 2007). Now, it is widely applied to study the sexual species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. analysis of Arius manillensis and Arius dispar Identification and measurement of specimens pelvic) and unpaired (anal and caudal) fins were significantly between males and females of C. gongota where the group dimorphism and ontogeny in fishes (Kitano et al., 2012) between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, varied (F > 5.62, P 0.01) while no statistical divergences (F was correctly classified as 97.66% (F = 7.01, P 0.01). The Echeverria TW (1986), Sexual dimorphism in four species of including their intraspecific phenotypic differences. Even At first, external form and/or ornamentation of the collected was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. < 1.14, P > 0.05) were observed in the lengths of dorsal, low overlap and high spread of DFA values explained higher rockfish genus Sebastes (Scorpaenidae), though sexual distinctions between males and females have specimens were examined to find out any traits as reliable abdomen than those of males may be due to larger gonads and minimal variation on the tail between males and females Cobitoidei), Raffles Bulletin of Zoology Supplement pectoral, pelvic and˂ caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Environmental Biology of Fishes 15: 181-190, Saurabh S, Sridhar N, Barlya G, Hemaprasanth, been studied on some loaches (Bohlen, 2008; Plongsesthee et indicators in their body followed by Plongsesthee et al. demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota (2015), Landmark based geometric morphometric 26: 1-199. (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that analysis on body shape variation of Mesopristes Eros T (2003), The reproductive characteristics of a spined B RW (36.22%), RW (24.42 %), RW (9.38%), RW (6.87%), Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua hypothesis is that there is no significant variations between individual was measured with a digital balance (HD-602ND, 1 2 3 4 more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes cancellatus (Cuvier, 1829), Advanced Environmental loach population (Osteichthyes, Cobitidae) based on RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora other RW scores. The first two relative warps accounted for 111: 977-1016. against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, 60.64% of total variance in 24 landmark points. Positioning species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. of Anthropology 36: 261-281. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. University Press, p 466. Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, Talwar PK and Jhingran AG (1991), Inland fishes of India there were no significant variations in the lengthsę of pectoral, Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. species are important tools for fish stock assessment. The Solea lascaris (Risso, 1810) along the Portugal coast, which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. compared the mean of ranked dissimilarities between groups˂ and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color loaches (exceptč three species of Cobitis reported by between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 Fig. 1. Sampling area (black circle: 25.924° N, 88.724° E) in the Atrai River basin of Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive Dinajpur district of Bangladesh 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112. Akter, Azom, Sabuz, Islam and Islam 189

They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in Table 1. Descriptive statistics and one-way ANOVA (P = 0.05) of body size and different fin’s lengths with their base rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen distances (cm) between sexes of C. gongota greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism 2 stickleback (Gasterosteus aculeatus), Copeia, pp abdominal shape as a reproductive structure of mature fishes caught fishes by using fine meshed seine net (15 × 3.5 m , and 4). In contrast, males had thin and slightly pointed for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and may be due to genetical, environmental or their combinations AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity General Male 336-349. would be expected to change during spawning season mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) pectoral and pelvic fins compared to the females. Besides, Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) observation Min Max Mean±SE Min Max Mean±SE F-value P-value (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, Department of Fisheries Biology and Genetics under Hajee WB 2.96 12.71 6.03±0.26 2.97 18.16 7.78±0.40 8.68 0.004 cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, L 6.20 10.65 7.92±0.11 6.20 11.55 8.50±0.15 7.04 0.009 the rough surface while males carried whitish colored smooth points that cluster together had similar shapes but far capoeta gracilis) (Pisces: Cyprinidae) in the Tajan stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. illustrate and quantify the structural variations of animal taxa S uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low dimorphism in body shapes of the spotted barb fish, using a more significant approach (Adams et al., 2004; Slice, Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body removed showed different shapes (Fig. 6). A discriminant (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main River (Iran), Hydrobiologia 673: 41-52. Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, LPcF 0.90 1.50 1.20±0.02 0.79 1.70 1.22±0.02 0.26 0.608 Puntius binotatus of Lake Buluan in Mindanao, Santos BS and Quilang JP (2012), Geometric morphometric weight) and distances between bases of paired (pectoral and function analysis (DFA) was used to judge distinctions 2011,03161,x 2007). Now, it is widely applied to study the sexual D 0.40 0.75 0.55±0.01 0.40 0.80 0.61±0.01 11.65 0.001 species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. analysis of Arius manillensis and Arius dispar Identification and measurement of specimens PcFB pelvic) and unpaired (anal and caudal) fins were significantly dimorphism and ontogeny in fishes (Kitano et al., 2012) between males and females of C. gongota where the group between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako L 0.95 1.50 1.18±0.02 0.65 1.60 1.21±0.02 0.54 0.464 varied (F > 5.62, P 0.01) while no statistical divergences (F Echeverria TW (1986), Sexual dimorphism in four species of Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, including their intraspecific phenotypic differences. Even PvF was correctly classified as 97.66% (F = 7.01, P 0.01). The was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. At first, external form and/or ornamentation of the collected < 1.14, P > 0.05) were observed in the lengths of dorsal, rockfish genus Sebastes (Scorpaenidae), the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. though sexual distinctions between males and females have DPvFB 0.28 0.55 0.37±0.01 0.25 0.74 0.42±0.01 7.85 0.006 low overlap and high spread of DFA values explained higher abdomen than those of males may be due to larger gonads and minimal variation on the tail between males and females specimens were examined to find out any traits as reliable ˂ Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Environmental Biology of Fishes 15: 181-190, Cobitoidei), Raffles Bulletin of Zoology Supplement been studied on some loaches (Bohlen, 2008; Plongsesthee et L 0.55 1.20 0.84±0.02 0.09 1.50 0.91±0.02 0.99 0.321 pectoral, pelvic and caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota Saurabh S, Sridhar N, Barlya G, Hemaprasanth, indicators in their body followed by Plongsesthee et al. DF (2015), Landmark based geometric morphometric 26: 1-199. (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each L 0.30 0.85 0.52±0.01 0.35 1.00 0.57±0.01 5.62 0.019 (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that Eros T (2003), The reproductive characteristics of a spined B AF analysis on body shape variation of Mesopristes Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua hypothesis is that there is no significant variations between RW1 (36.22%), RW2 (24.42 %), RW3 (9.38%), RW4 (6.87%), more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes loach population (Osteichthyes, Cobitidae) based on individual was measured with a digital balance (HD-602ND, L 1.20 1.80 1.52±0.02 0.90 2.02 1.49±0.02 1.14 0.287 cancellatus (Cuvier, 1829), Advanced Environmental CF RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. DCFB 0.45 0.80 0.57±0.01 0.40 0.97 0.61±0.01 5.68 0.019 variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum WB, Body weight; LS, standard length; LPcF, length of pectoral fin; DPcFB, distance between bases of pectoral fin; LPvF , length of of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora pelvic fin; DPvFB, distance between bases of pelvic fin; LDF, length of dorsal fin; LAF, length of anal fin; LCF, length of caudal other RW scores. The first two relative warps accounted for 111: 977-1016. against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, fin; DCFB, distance between bases of caudal fin (length of caudal peduncle) 60.64% of total variance in 24 landmark points. Positioning species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. of Anthropology 36: 261-281. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. University Press, p 466. Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, Talwar PK and Jhingran AG (1991), Inland fishes of India there were no significant variations in the lengthsę of pectoral, Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. species are important tools for fish stock assessment. The Solea lascaris (Risso, 1810) along the Portugal coast, which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: Fig. 2. a) Length and distances of unpaired fins of Canthophrys gongota: 5 to 8 (LDF), length of dorsal fin; 13 to 16 observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, (LAF), length of anal fin; 9 to 10 (LCF), length of caudal fin; 9 to 12 (DCFB), distance between caudal fin bases. b) variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of Location of 24 landmark points of this loach: 1) Tip of snout; 2) Middle of eyes; 3) Posterior of head; 4) Projection of 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. operculum on dorsal profile; 5) Anterior insertion of dorsal fin; 6) Tip of posterior portion of dorsal fin; 7) Tip of compared the mean of ranked dissimilarities between groups˂ and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra anterior portion of dorsal fin; 8) Posterior insertion of dorsal fin; 9) Upper margin of caudal peduncle; 10) Tip of upper to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. portion of caudal fin; 11) Tip of lower portion of caudal fin; 12) Lower margin of caudal peduncle; 13) Posterior was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color loaches (exceptč three species of Cobitis reported by insertion of anal fin; 14) Tip of posterior portion of anal fin; 15) Tip of anterior portion of anal fin; 16) Anterior between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 insertion of anal fin; 17) Posterior insertion of pelvic fin; 18) Tip of posterior portion of pelvic fin; 19) Tip of anterior Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive portion of pelvic fin; 20) Anterior insertion of pelvic fin; 21) Superior insertion of pectoral fin; 22) Insertion of 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: operculum on ventral profile; 23) Posterior edge of lower jaw bone; and 24) Center of upper and lower jaw possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112. 190 Sexual dimorphism of Canthophrys gongota 54(2) 2019

They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Digitalization of images and landmarks Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area During photography, each specimen placed in the center of a Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at dissecting pad (32 × 23 cm2) with a left side of its body References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. facing. A total of 64 males and 64 females were taken into In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai consideration for their photographs (4000 × 3000 pixels, 180 (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in dpi) using a digital camera (Canon PowerShot SX510 HS) rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen where fins of each fish were spread out and pinned in place to greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism 2 stickleback (Gasterosteus aculeatus), Copeia, pp caught fishes by using fine meshed seine net (15 × 3.5 m , offer a distinct view of insertion points into their body. For and 4). In contrast, males had thin and slightly pointed for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity abdominal shape as a reproductive structure of mature fishes may be due to genetical, environmental or their combinations 336-349. would be expected to change during spawning season mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) measuring, a ruler was placed against the lower edge of pectoral and pelvic fins compared to the females. Besides, Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the dissecting pad. Twenty-four landmarks (equal to 24 x and 24 females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, Department of Fisheries Biology and Genetics under Hajee y coordinates) were selected to analyze body shape cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, the rough surface while males carried whitish colored smooth illustrate and quantify the structural variations of animal taxa differences between the sexes using landmark-based points that cluster together had similar shapes but far uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low capoeta gracilis) (Pisces: Cyprinidae) in the Tajan dimorphism in body shapes of the spotted barb fish, stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body using a more significant approach (Adams et al., 2004; Slice, geometric morphometrics. Pins inserted on each specimen at removed showed different shapes (Fig. 6). A discriminant (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main River (Iran), Hydrobiologia 673: 41-52. Puntius binotatus of Lake Buluan in Mindanao, Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, weight) and distances between bases of paired (pectoral and Santos BS and Quilang JP (2012), Geometric morphometric 2007). Now, it is widely applied to study the sexual all landmarks before taking photographs to make sure the function analysis (DFA) was used to judge distinctions species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. 2011,03161,x Identification and measurement of specimens pelvic) and unpaired (anal and caudal) fins were significantly analysis of Arius manillensis and Arius dispar dimorphism and ontogeny in fishes (Kitano et al., 2012) accuracy of landmark locations during digitization. Multiple between males and females of C. gongota where the group between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako Echeverria TW (1986), Sexual dimorphism in four species of Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, including their intraspecific phenotypic differences. Even photographs of an individual were taken to check the varied (F > 5.62, P 0.01) while no statistical divergences (F was correctly classified as 97.66% (F = 7.01, P 0.01). The was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. At first, external form and/or ornamentation of the collected rockfish genus Sebastes (Scorpaenidae), the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. acquisition of a quality image. After photography, images < 1.14, P > 0.05) were observed in the lengths of dorsal, low overlap and high spread of DFA values explained higher abdomen than those of males may be due to larger gonads though sexual distinctions between males and females have specimens were examined to find out any traits as reliable and minimal variation on the tail between males and females Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Cobitoidei), Raffles Bulletin of Zoology Supplement reviewed to select the best image for each specimen. pectoral, pelvic and˂ caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The Environmental Biology of Fishes 15: 181-190, Saurabh S, Sridhar N, Barlya G, Hemaprasanth, been studied on some loaches (Bohlen, 2008; Plongsesthee et indicators in their body followed by Plongsesthee et al. demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota (2015), Landmark based geometric morphometric 26: 1-199. Landmark clarity, lighting and angle were examined when (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each Fig. 3. a) Body coloration and abdomen between sexes of (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that analysis on body shape variation of Mesopristes Eros T (2003), The reproductive characteristics of a spined B selecting a photograph. Once chosen, photograph file was RW (36.22%), RW (24.42 %), RW (9.38%), RW (6.87%), Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua hypothesis is that there is no significant variations between individual was measured with a digital balance (HD-602ND, C. gongota (Standard length 10.65 and 11.55 cm; body 1 2 3 4 more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes cancellatus (Cuvier, 1829), Advanced Environmental loach population (Osteichthyes, Cobitidae) based on renamed with specimen identity number to classify them RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, weight 12.71 and 18.16 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. accurately as their sex (Santos and Quilang, 2012; Reiss and variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances respectively. b) Length of paired fins and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed Grothues, 2015). All pooled images were processed for between bases (LPcF, length of pectoral fin; LPvF, 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum digitization (Fig. 2) to decide sexual dimorphism where length of pelvic fin; DPcFB, distance between pectoral of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora landmarks were digitized using tpsDig2 software (Rohlf, fin bases; DPvFB, distance between pectoral fin bases) other RW scores. The first two relative warps accounted for 111: 977-1016. against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, 2006). After opening the images through this software, the 60.64% of total variance in 24 landmark points. Positioning species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. ruler was set for measuring distance and then mouse point in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review was set on two landmark points to get correct and reliable similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. of Anthropology 36: 261-281. measurements. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of Statistical analysis males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar University Press, p 466. Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. More or less mature fishes were used to lessen the effects of Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, intrapopulation shape variations because of allometric Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Talwar PK and Jhingran AG (1991), Inland fishes of India there were no significant variations in the lengthsę of pectoral, Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New growth pattern (Dorado et al., 2012). Specimen data put in However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. rows and two-dimensional landmarks (x and y coordinates) species are important tools for fish stock assessment. The Solea lascaris (Risso, 1810) along the Portugal coast, which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on along each row for general procrustes alignment (GPA) by landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. rotating and translating to major axis for linear space (Rohlf us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual and Slice, 1990). The resulting procustes distances were used between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: to calculate in Multivariate Analysis of Variance Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and (MANOVA) to observe whether the differences in of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and morphological traits between sexes of C. gongota are with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological significant or not. The analysis of similarity (ANOSIM) is a Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, Fig. 4. Sexual dimorphism in the paired fins between variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish hypothetical test that was used to evaluate the phenotypic tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of sexes of C. gongota 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. variations between sexes of this loach. The value of ‘R’ was within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. calculated as 4 (r -r )/N(N-1), where ‘r , is the average rank compared the mean of ranked dissimilarities between groups˂ b w b and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra of all distances between groups, ‘r ’ mean rank of all to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric w dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color distances within groups and ‘N’ is the total number of sample loaches (exceptč three species of Cobitis reported by between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 (Clarke, 1993). The thin-plate spline algorithm was used to Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive calculate the mean body shape between sexes of C. gongota 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: (Bookstein, 1991). Discriminant Function Analysis (DFA) possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112. Akter, Azom, Sabuz, Islam and Islam 191

They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism 2 stickleback (Gasterosteus aculeatus), Copeia, pp caught fishes by using fine meshed seine net (15 × 3.5 m , and 4). In contrast, males had thin and slightly pointed AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity abdominal shape as a reproductive structure of mature fishes for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and may be due to genetical, environmental or their combinations 336-349. would be expected to change during spawning season mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) pectoral and pelvic fins compared to the females. Besides, Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, Department of Fisheries Biology and Genetics under Hajee cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, the rough surface while males carried whitish colored smooth illustrate and quantify the structural variations of animal taxa points that cluster together had similar shapes but far uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low capoeta gracilis) (Pisces: Cyprinidae) in the Tajan dimorphism in body shapes of the spotted barb fish, stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body removed showed different shapes (Fig. 6). A discriminant River (Iran), Hydrobiologia 673: 41-52. Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, using a more significant approach (Adams et al., 2004; Slice, (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main Puntius binotatus of Lake Buluan in Mindanao, Santos BS and Quilang JP (2012), Geometric morphometric weight) and distances between bases of paired (pectoral and function analysis (DFA) was used to judge distinctions 2011,03161,x 2007). Now, it is widely applied to study the sexual species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. analysis of Arius manillensis and Arius dispar Identification and measurement of specimens pelvic) and unpaired (anal and caudal) fins were significantly between males and females of C. gongota where the group dimorphism and ontogeny in fishes (Kitano et al., 2012) between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, varied (F > 5.62, P 0.01) while no statistical divergences (F was correctly classified as 97.66% (F = 7.01, P 0.01). The Echeverria TW (1986), Sexual dimorphism in four species of including their intraspecific phenotypic differences. Even At first, external form and/or ornamentation of the collected was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. < 1.14, P > 0.05) were observed in the lengths of dorsal, low overlap and high spread of DFA values explained higher rockfish genus Sebastes (Scorpaenidae), though sexual distinctions between males and females have specimens were examined to find out any traits as reliable abdomen than those of males may be due to larger gonads and minimal variation on the tail between males and females Cobitoidei), Raffles Bulletin of Zoology Supplement pectoral, pelvic and˂ caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Environmental Biology of Fishes 15: 181-190, Saurabh S, Sridhar N, Barlya G, Hemaprasanth, been studied on some loaches (Bohlen, 2008; Plongsesthee et indicators in their body followed by Plongsesthee et al. demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota (2015), Landmark based geometric morphometric 26: 1-199. (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that analysis on body shape variation of Mesopristes Eros T (2003), The reproductive characteristics of a spined B RW (36.22%), RW (24.42 %), RW (9.38%), RW (6.87%), Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua hypothesis is that there is no significant variations between individual was measured with a digital balance (HD-602ND, 1 2 3 4 more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes cancellatus (Cuvier, 1829), Advanced Environmental loach population (Osteichthyes, Cobitidae) based on RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora other RW scores. The first two relative warps accounted for 111: 977-1016. against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, 60.64% of total variance in 24 landmark points. Positioning species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. of Anthropology 36: 261-281. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. University Press, p 466. Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, Talwar PK and Jhingran AG (1991), Inland fishes of India there were no significant variations in the lengthsę of pectoral, Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. species are important tools for fish stock assessment. The Solea lascaris (Risso, 1810) along the Portugal coast, which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on Fig. 5. Relative splines and vectors showing shape landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. variation along the discriminators us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. compared the mean of ranked dissimilarities between groups˂ and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color loaches (exceptč three species of Cobitis reported by between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Fig. 6. PCA scatter plot showing the distribution of male and Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis female of C. gongota based on body shape (+ male;  female) Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112. 192 Sexual dimorphism of Canthophrys gongota 54(2) 2019

They show no external sexual dimorphism (Siddiqui et al., Materials and methods dissimilarity between the sexes of C. gongota (Table I; Fig. 2 Before dissection, photographs of the specimen were taken in Results and discussion respectively discriminating the sexes. The deformation grid Body shape variations between sexes i.e. sexual dimorphism previous ones. However, the males and females of C. gongota thesis work which is a partial requirement of Master of 17 -estradiol and 11-ketotestosterone levels, Fish Karakousis Y, Triantaphyllidis C and Economidis PS (1991), Rohlf FJ (2006), Tps Dig Version 2.10, Digitalized

2007) and reported in the rivers close to foothills (Kottelat, and 3). Finally, fish samples were dissected to collect their order to grasp their main sexual dimorphic characters using associated with CV1 illustrated that the most effective is the outputs of genetic changes mainly controlled by natural showed sexual dimorphism based on their size independent Science in Fisheries Biology and Genetics. Physiology and Biochemistry 35: 125-136. Morphological variability among seven populations of Landmarks and Outlines, Department of Ecology and Study area Sexual dimorphism through general observation β 2012) from May to June (Saha and Saha, 2011). As some gonads for precision of prediction by visual observation of geometric morphometric analysis. Individuals that had discriminators were 1, 2, 4, 23 (head region); 6, 7 (dorsal fin); selection, choice of a couple and ecological selection morphometric traits which were similar to Cobitis sp. (Buj, et Clarke KR (1993), Non-parametric multivariate analyses of brown trout, Salmo trutta, in Greece, Journal of Fish Evolution, New York, State University of New York at References fishes primarily exhibit monomorphic traits but sexual sexes. After gonad collection, sexes were finally detected by damaged fins (e.g. dorsal and caudal fins) not considered for 10, 11 (caudal fin); 21, 22 (bases of pectoral fin); 17, 20 (Blanckenhorn, 2005; Hassell et al., 2012) that were not al., 2014) and to eight-barbel loach Lefua sp. (Aoyama, changes in community structure, Australian Journal of Biology 38: 807-817. DOI:org/10,1111/j, Stony Brook. A total of 128 individuals (64 males and 64 females) of C. imaging and analysis. In this study, it was observed that females had a larger body (bases of pelvic fin) and 13, 16 (anal fin bases) between the considered in this study. This study reported that females of 1095-8649,1991,tb03620,x dimorphic characters between sexes are anticipated because observing their testes and ovary (Esmaeili et al., 2017). 2007). Using ANOSIM analysis, highly significant Ecology 18: 117-143. Rohlf FJ and Slice D (1990), Extensions of the procrustes gongota were collected directly from fishermen of the Atrai (standard length), broader abdomen, comparatively thick and sexes of this loach (Fig. 5). Besides, higher values of C. gongota were significantly larger in size than males which Adams DC, Rohlf FJ and Slice DE (2004), Geometric males and females show various reproductive roles for phenotypic variations also existed in the external morphology Kitano J, Mori S and Peichel CL (2007), Sexual dimorphism method for the optimal superimposition of landmarks, partner selection expressing their morphological variations River (25.924° N, 88.724° E) in Dinajpur district located in rounded paired fins (pectoral and pelvic) having relatively expansion factor were found in the head region for males were consistent with the morphology of Cobitis elongatoides between sexes of C. gongota which may due to different roles morphometrics: Ten years of progress following the Das MK, Baishya A, Sarkar UK, Lakra WS and Bordoloi S revolution, Italian Journal of Zoology 71: 5-16. in the external morphology of the threespine Systematic Zoology 39: 40-59. (Casselman and Schulte-Hostedde, 2004). Besides, the northwest region of Bangladesh (Fig. 1). Fishermen greater distances between bases of two fins than males (Fig. 3 (> 1.17) and in abdomen mainly in front of pelvic fin bases and Sabanejewia balcanica (Bohlen et al., 2008), C. played during their reproduction. These phenotypic changes (2012), Standard measurement and sexual dimorphism 2 stickleback (Gasterosteus aculeatus), Copeia, pp caught fishes by using fine meshed seine net (15 × 3.5 m , and 4). In contrast, males had thin and slightly pointed for females (> 0.58). calderoni (Valladolid and Przybylski, 2008) and AnvariFar H, Khyabani A, Farahmand H, Vatandoust S, of a Cobitid loach, Lepidocephalichthys goalparensis Saha BK and Saha A (2011), Fecundity and gonadal maturity abdominal shape as a reproductive structure of mature fishes may be due to genetical, environmental or their combinations 336-349. would be expected to change during spawning season mesh size 4 mm). Fishes were immediately (within 1.5-2.0 h) pectoral and pelvic fins compared to the females. Besides, Lepidocephalichthys (Havird et al., 2010). The reasons may (Pinheiro et al., 2005). Thin plate analysis between males and Anvari Far H and Jahageerdar S (2011), Detection of Pillai and Yazdani, 1976, International Journal of of Gongota loach Canthophrys gongota (Hamilton) (Hassell et al., 2012). Geometric morphometrics is a transported with ice box and carried to the laboratory of the females also had reddish orange (during spawning period) to Using principal components analysis (PCA), the variance of be that female of loach may convert their energy for growth females of gongota loach represented that variations were morphometric differentiation between isolated up- and Science Nature 3: 763-767. Kitano J, Mori S and Peichel CL (2012), Reduction of sexual (Cobitidae) in the habitat of the Someswari River, Department of Fisheries Biology and Genetics under Hajee cream (in pre and post-spawning time) colored ovaries with PCA and PCA were 79.68% and 8.23%, respectively. The downstream populations of Siah Mahi (Capoeta dimorphism in stream-resident forms of three-spined Bangladesh Journal of Scientific and Industrial graphical approach that provides more facilities to reveal, 1 2 rather than reproduction until the second year whereas male higher in the head and abdominal region compared to other Dorado EL, Torres MAJ and Demayo CG (2012), Sexual Mohammad Danesh Science and Technology University, the rough surface while males carried whitish colored smooth illustrate and quantify the structural variations of animal taxa points that cluster together had similar shapes but far uses more energy for breeding from their first-year life cycle body regions. Moreover, landmark plots presented low capoeta gracilis) (Pisces: Cyprinidae) in the Tajan dimorphism in body shapes of the spotted barb fish, stickleback Gasterosteus aculeatus, Journal of Fish Research 46: 573-578. Dinajpur, Bangladesh. testes. Moreover, body size (standard length and body removed showed different shapes (Fig. 6). A discriminant River (Iran), Hydrobiologia 673: 41-52. Biology, 80: 131-146. DOI:org/10,1111/j, 1095-8649, using a more significant approach (Adams et al., 2004; Slice, (Eros, 2003). Studies regarding sexual dimorphism of this overlaps of shapes in both sexes of C. gongota where main Puntius binotatus of Lake Buluan in Mindanao, Santos BS and Quilang JP (2012), Geometric morphometric weight) and distances between bases of paired (pectoral and function analysis (DFA) was used to judge distinctions 2011,03161,x 2007). Now, it is widely applied to study the sexual species have focused only on age and growth differences dissimilarities mainly on the head and abdominal regions (an Aoyama S (2007), Sexual size dimorphism, growth, and Philippines, AACL Bioflux 5: 321-329. analysis of Arius manillensis and Arius dispar Identification and measurement of specimens pelvic) and unpaired (anal and caudal) fins were significantly between males and females of C. gongota where the group dimorphism and ontogeny in fishes (Kitano et al., 2012) between males and females (Talwar and Jhingran, 1991). It area between pectoral and pelvic fin bases). In Mesopristes maturity of the fluvial eight-barbel loach in the Kako Kottelat M (2012), Conspectus cobitidum: an inventory of (Siluriformes: Ariidae) Populations in Laguna de Bay, varied (F > 5.62, P 0.01) while no statistical divergences (F was correctly classified as 97.66% (F = 7.01, P 0.01). The Echeverria TW (1986), Sexual dimorphism in four species of including their intraspecific phenotypic differences. Even At first, external form and/or ornamentation of the collected was also observed that females had large and extended cancellatus, differences were observed in the abdominal area River, Japan, Ichthyological Research 54: 268-276. the loaches of the world (Teleostei: Cypriniformes: Philippines, Philippine Journal of Science 141: 1-11. < 1.14, P > 0.05) were observed in the lengths of dorsal, low overlap and high spread of DFA values explained higher rockfish genus Sebastes (Scorpaenidae), though sexual distinctions between males and females have specimens were examined to find out any traits as reliable abdomen than those of males may be due to larger gonads and minimal variation on the tail between males and females Barazona CA, Demayo CG, Torres AMJ, and Gorospe JG Cobitoidei), Raffles Bulletin of Zoology Supplement pectoral, pelvic and˂ caudal fins between sexes of C. gongota and significant variations along mean values of˂ DFA. The Environmental Biology of Fishes 15: 181-190, Saurabh S, Sridhar N, Barlya G, Hemaprasanth, been studied on some loaches (Bohlen, 2008; Plongsesthee et indicators in their body followed by Plongsesthee et al. demonstration which is similar to a loach L. goalparensis (Barazona et al., 2015). The PCA scatter plot of C. gongota (2015), Landmark based geometric morphometric 26: 1-199. (Table I). first six relative warps scores (RWs) of Pahari Gutum were Raghavendra CH, Ragunath MR and Jayasankari P al., 2012) but without any earlier record. However, null (2012) with some modifications. Body weight (W ) of each (Das et al, 2012). The males of Schistura sexcauda have a showed little overlapping of plots which implied that analysis on body shape variation of Mesopristes Eros T (2003), The reproductive characteristics of a spined B RW (36.22%), RW (24.42 %), RW (9.38%), RW (6.87%), Mousavi-Sabet H and Anvarifar H (2013), Landmark-based (2013), Sexual dimorphism in Fishes, Aqua hypothesis is that there is no significant variations between individual was measured with a digital balance (HD-602ND, 1 2 3 4 more slender abdomen than females (Plongsesthee et al., landmarks represented significant differences in body shapes cancellatus (Cuvier, 1829), Advanced Environmental loach population (Osteichthyes, Cobitidae) based on RW (3.54%) and RW (2.41%) accounted to 82.85% of total morphometric variation between Cobitis keyvani and International, pp 30-32. two sexes of this loach. Therefore, an attempt was made to MEGA, Japan) to the nearest 0.1 g for male and female, 5 6 2012). Females of this gongota loach had a series of light of two sexes. In this study, PCA plots presented that both Biology 9: 32-36. gonad analysis, Biologia 58: 245-252. variance and eigen value of these scores were 0.077, 0.052, Cobitis faridpaki (Pisces: Cobitidae), with new habitat assess the sexual dimorphism of C. gongota with a view to respectively. Eight lengths of fins (cm) and their distances brown blotches along sides and a less dark patch beneath the sexes of this fish population converge or overlapped at low Esmaeili HR, Sayyadzadeh G and Chermahini MA (2017), Siddiqui KU, Islam MA, Kabir SMH, Ahmad M, Ahmed 0.0201, 0.015, 0.008 and 0.005, respectively. The percentage Blanckenhorn WU (2005), Behavioral causes and for C, faridpaki in the southern Caspian Sea basin, identify their key morphometric traits that will be convenient between bases (cm) were also taken with a vernier caliper to eyes compared to males which may possibly work as a level along the horizontal axis showing higher isolation Sexual dimorphism in two catfish species, Mystus ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum of RW was larger showing higher differences compared to consequences of sexual size dimorphism, Ethology Folia Zoologica 62: 167-175. to separate females from the males. the nearest 0.1 cm for each fish specimen to determine any 1 functional gesture to entice females for mating or to counsel between the sexes. Discriminant function analysis (DFA) pelusius (Solander, 1794) and Glyptothorax silviae ZNT and Hassan MA (2007), Encyclopedia of flora other RW scores. The first two relative warps accounted for 111: 977-1016. against males. Kottelat (2012) studied on over 60 loach could be a useful method to distinguish different species of Coad, 1981 (Teleostei: Siluriformes), Turkish Journal Mustafi P, Mar i Z, Dupli A, Mrakov i M, aleta M, and fauna of Bangladesh, Freshwater Fishes, Dhaka, 60.64% of total variance in 24 landmark points. Positioning species where all fishes carry small and extended body shape the same genus or different stocks of the same species with Bohlen J, Freyhof J and Nolte A (2008), Sex ratio and body of Zoology 41: 144-149. Zanella D, Buj I, Podnar M and Dolenec Z (2008), A Bangladesh, Asiatic Society of Bangladesh, p 300. in the plot relative to other individuals indicated the degree of with different colored ornamentations, spots, and blotches. A respect to stock management programs (Karakousis et al., size in Cobitis elongatoides and Sabanejewia newę loachč speciesę of ęthe genus Cobitisč ę inĘ Croatia, Slice DE (2007), Geometric Morphometrics, Annual Review similarity where individuals with positive amplitude on the sexually dimorphic black blotch present in pectoral fins of 1991). The overlap and spread of DFA represented 97.66% balcanica (Cypriniformes; Cobitidae) from a thermal Hassell EMA, Meyers PJ, Billman EJ, Rasmussen JE and Folia Zoologica 57: 4-9. of Anthropology 36: 261-281. first relative warp were similar in body shape and vice-versa. males S. aurantiaca, S. cf. aurantiaca and S. sexcuada while classification for C. gongota while 58.10%, 64.70% and spring, Folia Zoologica 57: 191-197. Belk MC (2012), Ontogeny and sex alter the effect of Nalbant TT (1994), Studies on loaches (Pisces, Ostariophysi, it is absent in females (Plongsesthee et al., 2012). In common, 44.10 for Cobitis sp., C. faridpaki and C. keyvani, predation on body shape in a live bearing fish: sexual Solem Q and Berg OK (2011), Morphological differences in Bookstein F, (1991), Morphometric tools for landmark data: Cobitidae), I, An evaluation of the valid genera of males have statistically larger pectoral fins than females in respectively (Mousavi-Sabet and Anvarifar, 2013). Besides, dimorphism, parallelism, and costs of reproduction, parr of Atlantic salmon Salmo salar from three regions geometry and biology, Cambridge, Cambridge Cobitidae, Travaux du Museum National d'Histoire most loaches such as C. jadovaensis (Mustafi et al., 2008) the individuals also grouped into 95.80% for Salmo salar University Press, p 466. Ecology and Evolution 2: 1738-1746. in Norway, Journal of Fish Biology 78: 1451-1469. Naturelle Grigore Antipa 34: 375-380. and S. cf. aurantiaca (Plongsesthee et al., 2012). However, (Solem and Berg, 2011) as different taxa. Buj I, Šanda R, Mar i Z, aleta M and Mrakov i M (2014), Havird JC, Page LM, Tangjitjaroen W, Vidthayanon C, Talwar PK and Jhingran AG (1991), Inland fishes of India ę Pinheiro A, Teixeira CM, Rego AL, Marques JF and Cabral there were no significant variations in the lengths of pectoral, Combining morphology and genetics in resolving Grudpan C and Udduang S (2010), A new species of and adjacent countries, Oxford-IBH Publishing, New However, variations between males and females of a fish HN (2005), Genetic and morphological variation of pelvic, caudal and dorsal fins between sexes of C. gongota taxonomy-A čSystematicę Ę revision of spinedč ę loaches Lepidocephalichthys (Teleostei: Cobitidae) with Delhi, p 1158. species are important tools for fish stock assessment. The which is similar to the morphology of S. mahnerti (Genus Cobitis; Cypriniformes, Actinopterygii) in the distinctive sexual dimorphism and comments on Solea lascaris (Risso, 1810) along the Portugal coast, landmark-based geometric morphometric approach enabled Valladolid M and Przybylski M (2008), Life history traits of (Plongsesthee et al., 2012). But, a significantly larger anal fin Adriatic Watershed, PloS One 9: e99833. relationships in southern lineages of Cobitidae, Fisheries Research 73: 67-78. us to quantify and visualize morphometric differences the endangered Iberian loach Cobitis calderoni in the was recorded in females than in males of this loach. Zootaxa 2557: 1-18. Plongsesthee P, Beamish FWH and Page LM (2012), Sexual between sexes of C. gongota. This finding will be useful to Casselman SJ and Schulte-Hostedde AI (2004), Reproductive River Lozoya, Central Spain, Folia Zoologica 57: Moreover, females of C. gongota also had significantly dimorphism in species of Schistura (Teleostei: Sexual size dimorphism using geometric morphology identify sexes of C. gongota species where alteration patterns roles predict sexual dimorphism in internal and Islam MR and Mia MJ (2016), Length-weight and 147-154. greater distances between the bases of pectoral, pelvic and Nemacheilidae) from the Mae Khlong basin and of sexes can be supportive to both in rearing and culturing external morphology of Lake Whitefish, Coregonus length-length relationships of five fish species in the During an experiment, a significant difference (P 0.01) was caudal fins compared to males. peninsular Thailand, Zootaxa 3586: 353-358. Vilizzi L and Ková V (2014), Alternative ontogenies and with other developmental aspects of this species. Lastly, this clupeaformis, Ecology of Freshwater Fishes 13: Atrai River, Dinajpur, Bangladesh, J Appl Ichthyol. 32: observed between sexes of C. gongota based on body shape developmental plasticity: implications for ecological Landmark-based geometric morphometric is an important landmark-based geometric morphometric study would be a 217-222. 1371-1373. Rahman AKA (2005), Freshwater fishes of Bangladesh, variations using MANOVA test (Wilk’s lambda ˂= 0.18, P and evolutionaryč studies on species complexes, Fish tool to examine the taxonomic and morphometric distinctions baseline for future study on loaches within and among Chaki N, Jahan S, Fahad MFH, Galib SM and Mohsin ABM Islam MR, Azom MG, Faridullah M and Mamun M (2017), Dhaka, Bangladesh, Zoological Society of 0.01) representing sexual dimorphism. The ANOSIM and Fisheries 15: 523-531. within and between species (AnvariFar et al., 2011; Vilizzi populations. (2015), Environment and fish fauna of the Atrai River: Length-weight relationship and condition factor of 13 Bangladesh, pp 18-394. compared the mean of ranked dissimilarities between groups˂ and Ková , 2014). There are no previous findings on sexual global and local conservation perspective, Journal of fish species collected from the Atrai and Brahmaputra to mean of ranked dissimilarities within groups exhibiting Reiss P and Grothues TM (2015), Geometric morphometric dimorphism of C. gongota (Pahari Gutum) or any other Acknowledgements Fisheries 2: 163-172. rivers, Bangladesh, J Bio Env Sci. 10: 123-133. was also used to evaluate the total amount of difference variations (R = 0.61, P < 0.01) between males and females analysis of cyclical body shape changes in color loaches (exceptč three species of Cobitis reported by between males and females. Principal Component Analysis (Table III). This deformation grid depicted the shape Chu-Koo F, Dugué R, Aguilar MA, Daza AC, Bocanegra FA, Islam MR, Roy S, Mia MJ and Amin AKMR (2018), pattern variants of Cichla temensis Humboldt, 1821 Mousavi-Sabet and Anvarifar, 2013) using truss-networks Authors are gratified to fishermen collecting the specimens. (PCA) scatter diagram was also used to visualize the degree transformation associated with first canonical variate (CV ) Veintemilla CC, Duponchelle F, Renno JF, Tello S and Length-weight and length-length relationships of four (Perciformes: Cichlidae) demonstrates reproductive 1 based geometric morphometric analysis. Therefore, it is not They are also thankful to the Department of Fisheries of differences between the sexes of this species. axis where eigen value, % of variance and Mahalanobis Nuñez J (2009), Gender determination in the Paiche or small fishes from the Atrai River, Dinajpur, energy allocation, Neotropical Ichthyology 13: possible to compare the contemporaneous results with Biology and Genetics providing logistic supports during a distances between group were 1.77, 99.22% and 2.64, Pirarucu (Arapaima gigas) using plasma vitellogenin, Bangladesh, J Appl Ichthyol. 34: 200-202. 103-112.