Himantura Gerrardi Research Articles

Effects of Urea Removal on the Stable Isotopes δ13C and δ15N in Rays from the Coastal Waters of Peninsular Malaysia

Highlight Research This is the first stable isotopes study of rays from Malaysian waters Urea extraction significantly enriched the δ15N values (‰) Urea removal is obliged for stable isotope studies on rays Such methodological information is critical for marine research in the region Abstract This is the first reported record of stable isotope values for elasmobranch rays within Malaysian waters, and serves as an important baseline methodological information for future studies investigating stable isotope values in both shark and ray species in the region. This study examined the effects of urea removal on the stable isotopes values of δ13C and δ15N in muscle tissues sampled from several elasmobranch rays species, namely Pastinachus atrus, Rhinoptera javanica, Himantura gerrardi, Himantura uarnak and Aetobatus ocellatus. Individual ray species were collected in July and August of 2018, from the coastal waters of Terengganu State, Malaysia. Urea removal was performed by soaking muscle tissue samples in deionised water for at least 24 hours before being dehydrated. The resulting stable isotope values of these samples were compared to samples that did not undergo the urea removal process. Stable isotope values were individual and species-specific, however, the effect of urea removal was significant for δ15N values but did not significantly affect the δ13C values. We conclude that removing urea from elasmobranch samples before stable isotope analysis is advisable to draw correct conclusions about the animal’s diets.

Technology of Free Chrome Tanning Process: Optimal Level of Formaldehyde as Tanning Agent for Mondol Stingray (Himantura gerrardi)

Chrome (VI) has a high level of toxicity. Formaldehyde is potential to be developed as a substitute of chrome tanning agent. The aims of this study are to explain the amount of formaldehyde bound, shrinkage temperature, tensile strength, and tear strength on Mondol stingray (Himantura gerrardi) leather. Pickled mondol stingray has been used as raw material. The study was divided into 4 treatments, that is P.I (formaldehyde 2%), P.II (formaldehyde 4%), P.III (formaldehyde 6%), and P.IV (formaldehyde 8%). The method used is drum tanning. Shrinkage temperatures, tensile strength and tear strength of P.I and P.II are significantly different from P.III and P.IV, but P.I is not significantly different from P.II, whereas P.III is not significantly different from P.IV. P.III is shown to improve the quality of leather stingray more than P.I and P.II, and has fulfilled the requirements of leather stingray according to SNI. 06-6121-1999. It can be concluded that the optimal level of formaldehyde tanning agent that can be used as a chrome tanning agent substitute in tanning Mondol stingray skin is formaldehyde 8% (P.III).

Exploring Singapore\u2019s consumption of local fish, vegetables and fruits, meat and problematic alcohol use as risk factors of depression and subsyndromal depression in older adults

BackgroundDepression is a chronic mental disorder that severely impacts the older adult population globally. Nutritional psychiatry is an approach that has gained traction over the years. Exploring locally relevant consumption of common types of fish, vegetables and fruits (V&F), meat and problematic alcohol use (PAU) as risk factors associated with depression and subsyndromal depression (SSD) could reveal modifiable factors that could be targeted in the local older adult population in Singapore.MethodsData collected from the Well-being of the Singapore Elderly (WiSE) study, a cross-sectional population-based epidemiological study of Singapore’s older adult population was analysed for the purposes of this study. Two thousand five hundred sixty-five participants were recruited and comprised of Singapore citizens and permanent residents aged ≥60 years. Data on fish, meat, and V&F consumption were collected using the sociodemographic and risk factor questionnaire. The CAGE (Cut, Annoyed, Guilt, and Eye-opener) questionnaire was used to determine PAU. The Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy (GMS-AGECAT) was used to obtain participants’ diagnosis of depression or SSD. A multinomial logistic regression was used to explore the relationship between depression and dietary factors.ResultsConsumption of V&F in the last 3 days was less likely to be associated with depression and SSD. Frequent consumption of specific species of fish was associated with depression and SSD. PAU and the frequent consumption of Himantura gerrardi (stingray) were more likely to be associated with SSD. Finally, meat consumption was more likely to be associated with depression and SSD.ConclusionsThe preliminary findings of the study support a need for healthy eating for the older adult population in Singapore. Further directions include a more thorough health and nutrition survey to capture accurate diets among the older adults in Singapore.

Study of stingray harvesting, marketing and utilization in Cox’s Bazar, Bangladesh

The present study was conducted to assess the harvesting procedures, nutritional value of stingray in the coastal district Cox’s Bazar, Bangladesh and its utilization as value-added product. Data were collected through direct observation, focus group discussion, questionnaire interview and cross check interview. It was found that stingray was mainly caught by artisanal fishery using gill net, set bag net and long line within 5-40 m depth ranges about 100-200 km at west direction, 10-60 km at south direction and 50-100 m depth ranges about 60-100 km at southwest direction from Fishery ghat, Cox’s Bazar. In the west direction, stingray harvesting grounds were Sonar char, Rupar char, Char Gongmoti and Dublar char in Patuakhali district, and Cox’s Bazar coast, Teknaf coast, St. Martin’s island coast and the south patches at south direction and middle ground at southwest direction. Generally stingrays was harvested throughout the year but were abundant during December and January. At fish landing center, the supply chain of stingray from fishermen to consumers passed through a number of intermediaries e.g., dealer, wholesaler, retailer and supplier. The market value of stingray varied where fishermen sold at 90-140 Tk/kg that passed through these channels and at last consumers got it at 140-250 Tk/kg. Six species of stingray were found in Fishery ghat, Cox’s Bazar namely Himantura gerrardi, Dasyatis bennetti, Himantura uarnak, Himantura undulata, Himantura bleekeri and Neotrygon kuhlii. Among them H. gerrardi and H. bleekeri were available and very popular in the market. The average moisture, protein, lipid, carbohydrate and ash content of H. bleekeri were determined as 78.08%, 14.80%, 4.31%, 0.95% and 1.87%, respectively and total energy content 103.78 Kcal. Three utilization processes were investigated in this study namely fish ball of stingray, stingray recipe with sour of tomato and stingray recipe with sour of tamarind. Fish ball was preferred as an excellent product and others were as very good products. Dried stingray products were only utilized by tribal peoples. Dried meat, skin and spine were exported abroad namely to China, Thailand, Myanmar and Singapore.
 J. Bangladesh Agril. Univ. 16(3): 539–544, December 2018

Feeding habits and trophic level of sharpnose stingray, Himantura gerrardi (Elasmobranchii Dasyatidae) in northern Oman Sea: effects of sex and size class

The feeding habits and trophic level of Himantura gerrardi were studied according to sex and size classes utilizing 80 individuals obtained using bottom trawl between May and December 2014 from Oman Sea. Collected specimens were divided in three size classes (small 58 cm) based on disk width (DW). Preys were identified in seven main zoological categories, where crustacean and polychaetes were the dominant in diets, which indicating this species is a demersal dwelling species. No significant differences were observed between sexes, but size classes showed a significance differences in their diets. Also, results showed a decreasing of feeding overlap between size classes by increasing of DW, suggesting that intraspecific competition reduced, which allows the coexistence of different size classes. Trophic level was positively correlated with the DW, which were lower than 4.0 for both sexes and different size classes, placing it in intermediate trophic level.

Genetic identity of eutetrarhynchids from the Persian Gulf, with intraindividual and intraspecific variability of Prochristianella butlerae Beveridge, 1990

The examination of the two batoid species, Pastinachus sephen (Forsskål) and Himantura gerrardi (Gray), resulted in a morphologic identification of the five eutetrarhynchid species, namely Parachristianella indonesiensis Palm, 2004 reported for the first time from Himantura gerrardi, Pa. monomegacantha Kruse, 1959, Prochristianella clarkeae Beveridge, 1990, Pr. butlerae Beveridge, 1990 and Dollfusiella spinulifera (Beveridge et Jones, 2000). By sequencing the partial 28S rDNA and calculating the genetic distances between the morphologically identified specimens from the Persian Gulf and their allopatric morphological conspecifics as well as using a phylogeny, the specimens of the Persian Gulf were considered as the allopatric conspecifics of Parachristianella indonesiensis, Pa. monomegacantha and Prochristianella clarkeae. Since the specimens of Dollfusiella from the Persian Gulf and D. spinulifera from Australia had a high genetic distance and placed in two separate clades, the Iranian specimens of Dollfusiella were treated as the cryptic species of D. spinulifera. Following the treatment of Prochristianella macracantha Palm, 2004 as the synonym of Pr. butlerae Beveridge, 1990, it was also expressed that although Pr. butlerae appeared to be a variable species in terms of its metric data, there was an identical oncotaxy in all the conspecifics. A detail examination of the specimens from the Persian Gulf as well as Australian voucher specimens revealed a great intraindividual and intraspecific variability in this species. Since, the sequence information is only available for the Iranian specimens and there is no possibility to evaluate the genetic distance and their monophyly, we consider these two allopatric populations as one species.

Length-weight relationships for 10 elasmobranch species from the Oman Sea

Length–weight relationships (LWRs) were estimated for ten elasmobranch species from Iranian waters of the Oman Sea. All specimens were collected by bottom trawl (mesh size 80 mm in the cod end) between May and December 2014. A total of 509 individuals (107 Torpedo sinuspersici, 68 Rhinobatos punctifer, 63 Chaenogaleus macrostoma, 72 Himantura walga, 80 Himantura gerrardi, 58 Gymnura poecilura, 4 Himantura uarnak, 4 Rhinoptera javanica, 14 Aetobatus flagellum, and 39 Pastinachus sephen) were sampled and studied. Results showed that most species had positive allometric or isometric growth but that more studies were needed for final decisions on growth patterns. Both the disk length-body weight (DL/BW) and disk width-body weight (DW/BW) relationships also showed a good fit, reinforcing the credibility of the data in relation to the LWRs. This study is the first report of LWRs for these elasmobranchs in the northern Oman Sea.

Complete mitochondrial genome of the Sharpnose stingray Himantura gerrardi (Myliobatiformes: Dasyatidae)

In this study, we presented the complete mitochondrial genome of the Sharpnose stingray Himantura gerrardi for the first time, which was 17,685 bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a putative control region. The overall nucleotide composition was 30.1% A, 27.5% C, 14.5% G and 28.0% T. A total of 22 bp overlaps and 83 bp short intergenic spaces were found in the mitogenome. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The origin of L-strand replication (OL) sequence formed a hairpin structure between the tRNA-Asn and tRNA-Cys genes. The termination associated sequence (TAS) formed a hairpin structure near the tRNA-Pro in the control region.

Population genetic structure of blue-spotted maskray Neotrygon kuhlii and two other Indo-West Pacific stingray species (Myliobatiformes: Dasyatidae), inferred from size-polymorphic intron markers

Exon-primed, intron crossing DNA markers (EPICs) were screened for Mendelian-like allele size polymorphisms in three stingray species (Himantura gerrardi, Neotrygon kuhlii and Taeniura lymna) from the central Indo-West Pacific, where they are commercially exploited. Four to 7 size-polymorphic intron loci were selected in a species, and were subsequently tested as genetic markers of stock structure. Sharp genetic differentiation was observed between populations within each species across the Indo-Malay-Papua archipelago (Weir and Cockerham's θ^-values reaching 0.153–0.557 over a few thousand kilometers). A trend of increasing genetic differentiation with increasing geographic distance was apparent in N. kuhlii, in which populations distant by 3000km were differentiated by an estimated θ^~0.375. This value was an order of magnitude higher than usually reported in coastal benthic teleost fishes and indicates strong sub-population structure. This is likely, at least partly, a consequence of the sedentary benthic habits of N. kuhlii at all life stages. Because replenishment of overexploited populations of N. kuhlii and two other stingray species from the central Indo-West Pacific is unlikely at ecological timescales, management should be planned at the local geographic scale.

Preliminary investigation on antimicrobial and proteolytic property of the epidermal mucus secretion of marine stingrays

Objective To determine the antibacterial, antifungal, minimum inhibitory concentration (MIC) and the protease activity of the stingray mucus Dasyatis sephen ( D. sephen) and Himantura gerrardi ( H. gerrardi). Methods Antimicrobial activity of crude aqueous, acidic and organic mucus extract was evaluated by disc diffusion method against human pathogens, MIC of the active samples were determined by spectrophotometric method and the protease activity which is responsible for the antimicrobial activity was determined by using zymogram method. Results The crude acidic extracts of both the species showed antibacterial activity against Salmonella typhi ( S. typhi), Klebsiella pneumoniae, Streptococcus aureus, Escherichia coli ( E. coli), Vibrio cholerae ( V. cholerae) and the acidic extracts of both the species exhibit antifungal activity against all the tested pathogens. Remaining extracts didn't show any inhibitory activity. The acidic extracts of H. gerrardi is significantly active against S. typhi, E. coli, V. cholerae, Trichophyton mentagrophytes ( T. mentagrophytes), Alternaria alternaria ( A. alternaria), Trichophyton rubrum ( T. rubrum), Candida tropicalis ( C. tropicalis) at the minimum concentration of 16μ g/mL, but the acidic extract of D. sephen required 32μ g/mL of protein to inhibit S.typhi, E. coli, Aspergillus niger ( A. niger), penicillium sp, T. mentagrophytes, A. alternaria. Both the D. sephen and H. gerrardi shows the proteolytic activity above the molecular mass of > 66 KDa. The characterization of protease class using inhibitors showed the presence of both serine and metallo protease in the the samples. Conclusions Protease activity present in the sting ray mucus is one of the key factor responsible for the antimicrobial activity and the results proved the role of mucus in the innate immunity.

Study of patient's injuries by stingrays, lethal activity determination and cardiac effects induced by Himantura gerrardi venom

Stingrays are common inhabitants in the northern waters of the Persian Gulf and Oman Sea. In the present study, the clinical aspects of injuries induced in three patients bitten by stingrays in Hormozgan province waters were first examined. The LD 50 of crude venom extract obtained from the most common stingray in Hormozgan province ( Himantura gerrardi) was then estimated by up-and-down dosing and double dose methods in mice. Third and finally, the cardiac symptoms induced by injection of the extract from the venomous spines were evaluated in rats. Intense pain was noticed in all human cases. Redness was observed in two cases, and spasm and seizure were each recorded in only one case. LD 50 of the venom extract in mice was about 100 mg kg −1. The observed cardiac symptoms in rats included an increase in pulse rate and various changes in electrocardiogram (ECG) parameters such as T and Q values, and PR and RR intervals.

Three Dendromonocotyle species (Monogenea: Monocotylidae) reported from captive rays, including D. lotteri sp. n. from Himantura gerrardi (Elasmobranchii: Dasyatidae) in the public aquarium at the Atlantis resort, Dubai

Dendromonocotyle lotteri sp. n. is described from the dorsal skin surface of the stingray Himantura gerrardi (Gray) on exhibit in the public aquarium at the Atlantis resort in Dubai. It is differentiated from all other Dendromonocotyle species by the unique morphology of the distal portion of the sclerotised male copulatory organ. Dendromonocotyle lotteri is the second representative in the genus with 56 marginal haptoral papillae having a papillae to loculus association represented numerically as 6-6-8-8. We found Dendromonocotyle colorni Chisholm, Whittington et Kearn, 2001 on the same host specimens at the Atlantis resort public aquarium and Dendromonocotyle kuhlii Young, 1967 on Neotrygon kuhlii (Müller et Henle) kept at Burgers' Zoo Aquarium in Arnhem, The Netherlands. Supplemental information is provided for both D. colorni and D. kuhlii. The presence of Dendromonocotyle infections in public aquaria and host specificity are discussed. A key to the 17 species of Dendromonocotyle is also provided.

Overview of South African Dendromonocotyle (Monogenea : Monocotylidae), with descriptions of 2 new species from stingrays (Dasyatidae) kept in public aquaria

Two new species, Dendromonocotyle citrosa n. sp. off Dasyatis chrysonota (Smith) from Two Oceans Aquarium in Cape Town and off Himantura gerrardi (Gray) from uShaka Sea World in Durban and D. ukuthena n. sp. off H. gerrardi and H. uarnak (Forsskal) also from uShaka Sea World in Durban, are described. These can be distinguished from previously described Dendromonocotyle species by the morphology of the distal portion of the male copulatory organ and the proximal part of the vagina. Vaginal morphology is proposed as an important diagnostic character for species in the genus. Dendromonocotyle colorni Chisholm, Whittington & Kearn, 2001 which was originally recorded from H. uarnak in Israel, was discovered on H. uarnak sympatrically with D. ukuthena n. sp. and with D. citrosa n. sp. and D. ukuthena n. sp. off H. gerrardi. Minor differences in the number of papillary sclerites, the presence of septal tripartite sclerites and in the number of eyespots were seen between D. colorni collected from H. uarnak and H. gerrardi from uShaka Sea World and those originally described off H. uarnak from Israel. We demonstrate that the position of the marginal hooklets can be used to determine the orientation of the haptor of all representative Dendromonocotyle species with or without hamuli. We conclude that Dendromonocotyle species may not be as host-specific as previously believed and that minor differences in morphology are host or geographically induced.

DNA barcoding Australasian chondrichthyans: results and potential uses in conservation

DNA barcoding – sequencing a region of the mitochondrial cytochrome c oxidase 1 gene (cox1) – promises a rapid and accurate means of species identification, and of any life history stage. For sharks and rays, it may offer a ready means of identifying legal or illegal shark catches, including shark fins taken for the profitable shark fin market. Here it is shown that an analysis of sequence variability in a 655 bp region of cox1 from 945 specimens of 210 chondrichthyan species from 36 families permits the discrimination of 99.0% of these species. Only the two stingarees Urolophus sufflavus and U. cruciatus could not be separated, although these could be readily distinguished from eight other congeners. The average Kimura 2 parameter distance separating individuals within species was 0.37%, and the average distance separating species within genera was 7.48%. Two specimens that clustered with congeners rather than with their identified species-cluster were noted: these could represent instances of hybridisation (although this has not be documented for chondrichthyans), misidentification or mislabelling. It is concluded that cox1 barcoding can be used to identify shark and ray species with a very high degree of accuracy. The sequence variability characteristics of individuals of five species (Aetomylaeus nichofii, Dasyatis kuhlii, Dasyatis leylandi, Himantura gerrardi and Orectolobus maculatus) were consistent with cryptic speciation, and it is suggested that these five taxa be subjected to detailed taxonomic examination to confirm or refute this suggestion. The present barcoding study holds out great hope for the ready identification of sharks, shark products and shark fins, and also highlights some taxonomic issues that need to be investigated further.

Long-term trends in the competitive shore fishery along the KwaZulu-Natal coast, South Africa

Twenty-four years (1977–2000) of competitive shore angling catch and effort data from the KwaZulu-Natal Coastal Anglers Union for the province of KwaZulu-Natal were analysed. Of a minimum of 117 species recorded, the most commonly caught species were dusky shark (Carcharhinus obscurus) (26%), milk shark (Rhizoprionodon acutus) (18%) and shad (Pomatomus saltatrix) (10%). By weight, the top species were dusky shark (34%) and diamond ray (Gymnura natalensis) (19%). All the above species showed considerable inter-annual variation in their respective contributions to annual catch. Probably as a result of changes in fishing patterns, dusky shark and milk shark showed a general decline in percentage contribution to catch over the period, while contributions of lesser guitarfish (Rhinobatos annulatus), giant guitarfish (Rhynchobatus djiddensis), diamond ray (Gymnura natalensis) and brown ray (Himantura gerrardi) increased. Mean overall annual cpue by number and weight showed a non-significant increase over the period, while each of the investigated species showed a constant trend in mean annual weight. There were high proportions of juveniles in the catches of dusky shark (100%), dusky kob (92%) and giant guitarfish (78%). Improvements made to the structure of shore angling competitions and the overall contribution of competition angling to resource management in South Africa is discussed.

Long-term trends in the competitive shore fishery along the KwaZulu-Natal coast, South Africa

Twenty-four years (1977–2000) of competitive shore angling catch and effort data from the KwaZulu-Natal Coastal Anglers Union for the province of KwaZulu-Natal were analysed. Of a minimum of 117 species recorded, the most commonly caught species were dusky shark (Carcharhinus obscurus) (26%), milk shark (Rhizoprionodon acutus) (18%) and shad (Pomatomus saltatrix) (10%). By weight, the top species were dusky shark (34%) and diamond ray (Gymnura natalensis) (19%). All the above species showed considerable inter-annual variation in their respective contributions to annual catch. Probably as a result of changes in fishing patterns, dusky shark and milk shark showed a general decline in percentage contribution to catch over the period, while contributions of lesser guitarfish (Rhinobatos annulatus), giant guitarfish (Rhynchobatus djiddensis), diamond ray (Gymnura natalensis) and brown ray (Himantura gerrardi) increased. Mean overall annual cpue by number and weight showed a non-significant increase over the period, while each of the investigated species showed a constant trend in mean annual weight. There were high proportions of juveniles in the catches of dusky shark (100%), dusky kob (92%) and giant guitarfish (78%). Improvements made to the structure of shore angling competitions and the overall contribution of competition angling to resource management in South Africa is discussed.

Phylogenetic Relationships within the Stingray GenusDasyatis(Chondrichthyes: Dasyatidae)

Abstract Phylogenetic relationships for 14 of 35 currently recognized Dasyatis species (Dasyatis americana, Dasyatis brevis, Dasyatis centroura, Dasyatis geijskesi, Dasyatis guttata, Dasyatis kuhlii, Dasyatis lata, Dasyatis longus, Dasyatis margaritella, Dasyatis pastinaca, Dasyatis sabina, Dasyatis say, Dasyatis violacea, and Dasyatis zugei), Pastinachus sephen (sometimes referred to as Dasyatis sephen), one Indo-West Pacific Himantura (Himantura gerrardi), and four outgroups (Gymnura micrura, Urobatis jamaicensis, Taeniura lymma, and amphi-American Himantura schmardae) were elucidated using parsimony analysis of 32 morphological characters. One most-parsimonious tree of 116 steps (CI = 0.345, HI = 0.655, RI = 0.64) was found. The analysis refutes monophyletic Dasyatis and Himantura and reveals Dasyatis kuhlii, D. violacea, and P. sephen to be basal among other ingroup species, with D. kuhlii as the most basal species. The genus Himantura is paraphyletic, with amphi-American H. schmardae as sister to a c...

Incidental capture of elasmobranchs by commercial prawn trawlers on the Tugela Bank, Natal, South Africa

Species composition, sizes, trends in occurrence and catch rates of elasmobranchs caught by prawn trawlers on the Tugela Bank of Natal, South Africa, were examined from May 1989 to June 1992. Seven endemic species were recorded, the remainder having Indo-West Pacific or western Indian Ocean distributions. Most sharks were between 0,5 and 1 m long and most of the Myliobatiformes were 0,5 m in disc width. The small sizes of trawl-caught elasmobranchs indicates that the Tugela Bank functions as a nursery area for several species. None of the species examined exhibited diel patterns in frequency of occurrence, but Gymnura natalensis, Himantura gerrardi, Dasyatis chrysonota chrysonota, Sphyrna lewini and the rhinobatids occurred more frequently in warmer months. One species, Halaelurus lineatus, was more frequently taken during cooler months. Himantura gerrardi, Sphyrna lewini, Mustelus mosis and Rhizoprionodon acutus were recorded more frequently in shallower trawls (20–33 m) and G. natalensis and D. c. chrysonota more frequently in deeper trawls (33–45 m). Trawl-induced mortality was shown to be species specific, S. lewini having the highest mortality (98%). Based on catch rates recorded and trawl fleet effort, it is calculated that 44 600 elasmobranchs were caught by Tugela Bank trawlers from 1989 to 1992. About 57% of these were returned to the water alive. These figures are compared to catches made by recreational anglers and the Natal Sharks Board during the same period.

ELASMOBRANCH DIVERSITY OF KALIMANTAN WATERS

A total of 2,310 individuals of elasmobranch fishes consisting of 60 species from 13 families were recorded from survey trips in Kalimantan waters. Six fish landing sites and markets in four provinces of Kalimantan were visited from September 2005 to November 2006. Some new records, endemic and new species were gathered during the surveys. Rays of Dasyatid family were the most common elasmobranch species occurring in this area. Himantura gerrardi, H. uarnak and H. uarnacoides (Dasyatidae) were the most common rays, whereas Chiloscyllium punctatum (Hemiscyllidae), Hemigaleus microstoma (Hemigaleidae), Carcharhinus amblyrhynchoides and C. dussumieri (Carcharhinidae) were the most common sharks recorded during this study. Some endemic and rare species were also recorded including Himantura lobistoma, H. pastinacoides, Pastinachus solocirostris (Dasyatidae) and Glyphis sp. (Carcharhinidae).