Published Oct 9, 2021


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Keny Kanagusuku

Pablo Dufflocq

Angie Sánchez-Rea

Ana A Huamantinco

Sergio Ramírez-Amaro



Shark skin is covered by small structures called dermal denticles whose functions are diverse, such as protection, bioluminescence, hydrodynamics, among other functions. These structures have a great variety of shapes and sizes, which can be a useful approach for specimen identification as diagnostic characters between species. The present study aims to describe the dermal denticles morphology of the broadnose seven-gill shark Notorynchus cepedianus, evaluating differences among life-stage (neonate, juvenile and adult), sex and body region (dorsal and ventral). For achieving it, 39 specimens were collected at six landing points along the Peruvian coast. The dermal denticles from two body regions
(dorsal and ventral) were photographed, measured (length, width, angle and density), and described using a stereoscope. Dermal denticles measures showed significant morphological differences between body regions as well as stages of development, but not between sexes. The differences are: (1) Crown shape: as the individual grows, it can be seen that the cross shape is losing, (2) Crown cusps: cusps length varied according to the stage of each individual, it was also observed that the lateral cusps are larger in dorsal than ventral region, and (3) Union peduncle - crown: adult specimens and both body regions, the observed union was very dimly and it did not have a defined shape. On the whole, these reported variations in measured traits could be useful as diagnostic characters to identify the stage of development at which the landed and marketed specimens are found.


description, placoid scale, Peru, taxonomic identification

ACOREMA (Áreas Costeras y Recursos Marinos). Los tiburones de la provincia de Pisco, Ica, Perú. 2014.

Ankhelyi MV, Wainwright DK, Lauder GV. Diversity of dermal denticle structure in sharks: Skin surface roughness and three‐dimensional morphology, Journal of morphology, 279: 1132–1154, 2018.
doi: 10.1002/jmor.20836

Branco CH. Dentículos dérmicos de tubarões da Costa Portuguesa: a sua utilização para identificação das diferentes espécies. Doctoral dissertation, Universidad de Lisboa, Portugal. 2009.

Castro JI. The sharks of North America. Oxford University Press. New York, 613 pp, 2011.

Chen G. A simple way to deal with multicollinearity, Journal of Applied Statistics, 39(9): 1893–1909, 2012.

Chernova OF & Vorob’eva EI. Polymorphism of the surface sculpture of placoid scales of sharks (Selachimorpha, Elasmobranchii). In Doklady Biological Sciences. MAIK Nauka/Interperiodica, 446(1): 316–319, 2012.
doi: 10.1134/S0012496612050067

Chirichigno N, Vélez J. Clave para identificar los peces marinos del Perú, Instituto del Mar del Perú -IMARPE, Callao, Perú. 2: 496, 1998.

Chirichigno N, Cornejo M. Catálogo comentado de los peces marinos del Perú. Instituto del Mar del Perú - IMARPE, Callao. 2001.

Compagno L, Dando M, Fowler S. Guía de campo de los tiburones del mundo, Omega, 2006.

Compagno LJV. Notorynchus cepedianus. The IUCN Red List of Threatened Species 2009:

Deynat PP & Séret B. Le revêtement cutané des raies (Chondrichthyes, Elasmobranchii, Batoidea). I-Morphologie et arrangement des denticules cutanés. Annales des sciences naturelles, Zoologie et biologie animale, 17(2): 65–83, 1996.
doi: 10.1016/S0003-4339(99)80004-5

Díez G, Soto M, Blancos J. Biological characterization of the skin of shortfin mako shark Isurus oxyrinchus and preliminary study of the hydrodynamic behaviour through computational fluid dynamics, Journal of Fish Biology, 87: 123–137, 2015.
doi: 10.1111/jfb.12705

Dillon EM, Norris RD, Dea AO. Dermal denticles as a tool to reconstruct shark communities, Marine Ecology Progress Series, 566: 117–134, 2017.
doi: 10.3354/meps12018

Dillon EM, Lafferty KD, McCauley DJ, Bradley D, Norris RD, Caselle JE, DiRenzo GV, Gardner JPA, O’Dea, A. Dermal denticle assemblages in coral reef sediments correlate with conventional shark surveys, Methods in Ecology and Evolution, 11(3): 362–375, 2020.
doi: 10.1111/2041-210X.13346

Dunnett C. A multiple comparison procedure for comparing several treatments with a control, Journal of the American Statistical Association, 50(272): 1096–1121, 1955.
doi: 10.1080/01621459.1955.10501294

Ebert DA. Biology of the sevengill shark Notorynchus cepedianus (Peron, 1807) in the temperate coastal waters of southern Africa. South African Journal of Marine Science, 17(1): 93–103, 1996.
doi: 10.2989/025776196784158545

Ebert DA, White WT, Ho HC. Redescription of Hexanchus nakamurai Teng 1962, (Chondrichthyes: Hexanchiformes: Hexanchidae), with designation of a neotype, Zootaxa, 3752(1): 20, 2013.
doi: 10.11646/zootaxa.3752.1.4

Ferrón H, Pla C, Martínez-Pérez C, Escudero-Mozo MJ, Botella H. Morphometric discriminant analysis of isolated chondrichthyan scales for palaeoecological inferences: the Middle Triassic of the Iberian Chain (Spain) as a case of study. 2014.

Ferrón HG, Botella H. Squamation and ecology of thelodonts, PloS one, 12(2): e0172781, 2017.

Ferrón HG, Paredes-Aliaga MV, Martínez-Pérez C, Botella H. Bioluminescent-like squamation in the galeomorph shark Apristurus ampliceps (Chondrichthyes: Elasmobranchii), Contributions to Zoology, 87(3): 187–196, 2018.
doi: 10.1163/1875986608703004

Ferrón HG, Herraiz, JL, Botella H, Martinez-Perez C. Pre-Messinian ecological diversity of Mediterranean sharks revealed by the study of their dermal denticles. [Diversidad ecologica pre-Messiniense en tiburones del Mediterraneo según un estudio de sus denticulos dermicos],
Spanish Journal of Palaeontology, 34(2): 289–298, 2019.

Finucci B, Barnett A, Cheok J, Cotton CF, Kulka DW, Neat FC, Pacoureau N, Rigby CL, Tanaka S, Walker TI. Notorynchus cepedianus. The IUCN Red List of Threatened Species 2020: e.T39324A2896914. 2020.
doi: 10.2305/IUCN.UK.2020-3.RLTS.T39324A2896914.en

Fisher R. The comparison of samples with possibly unequal variances, Annals of Eugenics, 9(2): 174–180, 1939
doi: 10.1111/j.1469-1809.1939.tb02205.x

Gilligan JJ, Otway NM. Comparison of dorsal and pectoral fin denticles for grey nurse, great white, and six whaler sharks from east Australian waters, In Journal and Proceedings of the Royal Society of New South Wales, 144 (3–4): 66–82, 2011.

Gonzalez-Pestana A, Kouri C, Velez-Zuazo X. Shark fisheries in the Southeast Pacific: A 61-year analysis from Peru. F1000Research, 3, 2014.
doi: 10.12688/f1000research.4412.2

Gosset W. The probable error of a mean, Biometrika, 6(1): 1–25, 1908.
doi: 10.1093/biomet/6.1.1

Grasa I. Caracterización morfológica y molecular de la especie Deania calcea (Lowe, 1839), Master dissertation, Universidade da Coruña, España. 2018.

IMARPE (Instituto del Mar del Perú). Guía para la determinación de tiburones de importancia comercial en el Perú. Instituto del Mar del Perú-IMARPE, Serie de Divulgación Científica, 1(2): 80, 2015.

Jolie M. Some implications of the acceptance of a delamination principle. In Orvig T, editor. Current problems of lower vertebrate phylogeny, Stockholm: Almqvist and Wiskell, 89–108, 1968.

Kemp NE. Integumentary system and teeth. In W. C. Hamlett (ed.), Sharks, Skates and Rays. John Hopkins University Press, Baltimore, Maryland, 43–68, 1999.

Komsta L. Package “mblm”, 2019.

Kriwet J, Benton MJ. Neoselachian (Chondrichthyes, Elasmobranchii) diversity across the cretaceous–tertiary boundary. Palaeogeography, Palaeoclimatology, Palaeoecology, 214: 181–194, 2004.
doi: 10.1016/j.palaeo.2004.02.049

Kriwet J, Kiessling W, Klug S. Diversification trajectories and evolutionary life-history traits in early sharks and batoids. Proceedings of the Royal Society B: Biological Sciences, 276: 945–951, 2008.
doi: 10.1098/rspb.2008.1441

Kruskal W, Wallis W. Use of rank in one-criterion variance analysis, Journal of the American Statistical Association, 48: 907–911, 1952.
doi: 10.1007/978-0-387-32833-1

Last PR, Stevens JD. Sharks and Rays of Australia. Melbourne, CSIRO Division of Fisheries, 513p, 1994.

Maechler M, Rousseeuw P, Struyf A, Hubert M, Hornik K, Studer M, Roudier P. Package “Cluster”. 2021.

Marshall LJ. The fin blue line: Quantifying fishing mortality using shark fin morphology, Doctoral dissertation, University of Tasmania, Australia. 2011.

Motta P, Habegger ML, Lang A, Hueter R, Davis J. Scale morphology and flexibility in the shortfin mako Isurus oxyrinchus and the blacktip shark Carcharhinus limbatus. Journal of morphology, 273: 1096–1110, 2012.
doi: 10.1002/jmor.20047

Muñoz-Chápuli R. Sobre la clasificación tipológica del esqueleto dérmico de escualos (Chondrichtyes), Miscelània zoológica, 9: 396–400, 1985.

PRODUCE (Ministerio de la Producción). Plan de Acción Nacional para la Conservación y Ordenamiento de Tiburones, Rayas y Especies Afines en el Perú (PAN Tiburón-Perú). Decreto Supremo Nº 002-2014. Lima, Perú, 2014.

Rangel BdS, Amorim AF, Kfoury Jr. JR, Rici REG. Microstructural morphology of dermal and oral denticles of the sharpnose sevengill shark Heptranchias perlo (Elasmobranchii: Hexanchidae), a deep-water species, Microscopy Research & Technique, 82: 1243–1248, 2019.
doi: 10.1002/jemt.23273

Raschi W, Elsom J. Comments on the structure and development of the drag reduction type placoid scale. In Indo-Pacific Fish Biology: Proceedings of the Second International Conference on Indo-Pacific Fishes. (Eds T. Uyeno, R. Arai, T. Taniuchi and K. Matsuura.), 408–424, 1986.

Raschi W, Tabit C. Functional aspects of Placoid Scales: A review and update. Marine and Freshwater Research, 43(1): 123, 1992.
doi: 10.1071/mf9920123

R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. 2021

Reif WE. Protective and hydrodynamic function of the dermal skeleton of elasmobranchs, Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 157: 133–41, 1978.

Reif WE. Evolution of dermal skeleton and dentition in vertebrates. In Evolutionary biology. Springer US. 287–368, 1982.
doi: 10.1007/978-1-4615-6968-8_7

Reif WE, Dinkelacker A. Hydrodynamics of the squamation in fast swimming sharks. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 184–187, 1982.

Reif WE. Squamation and ecology of sharks. Cour Forschungsinstitut Senckenb Band 78, Schweizerbart Science Publisher, Stuttgart. 1985a.

Reif WE. Functions of Scales and Photophores in Mesopelagic Luminescent Sharks. Acta Zoologica, 66(2), 111–118, 1985b.
doi: 10.1111/j.1463-6395.1985.tb00829.x

Romero M, Alcántara P, Verde K. Guía de campo para la determinación de tiburones en la pesca artesanal del Perú. Instituto del Mar del Perú-IMARPE, Perú. 2015.

Romero M. Manual para de identificación de troncos de tiburones de importancia comercial en el Perú. Instituto del Mar del Perú-IMARPE, Perú. 16, 2018.

Schaeffer B. The dermal skeleton in fishes. In Andrews SM, Miles RS, Walker AD, editors. Problems in vertebrate evolution. London: Academic Press, 25–52, 1977.

Shapiro S, Wilk M. An analysis of variance test for nomality (complete samples), Biometrika, 52: 591–611, 1965.
doi: 10.2307/2333709

Smith MM, Heemstra PC. Class Chondrichthyes, Smiths’ Sea Fishes, 39–147, 1986.
doi: 10.1007/978-3-642-82858-4_12

Southall EJ, Sims DW. Shark skin: a function in feeding. Proceedings of the Royal Society of London. Series B: Biological Sciences, 270(suppl_1): S47–S49, 2003.

Sullivan T, Regan F. The characterization, replication and testing of dermal denticles of Scyliorhinus canicula for physical mechanism of biofouling prevention, Bioinspiration & Biomimetics, 6: 1–11, 2011.
doi: 10.1088/1748-3182/6/4/046001

Tabachnick B, Fidell L. Using Multivariate Statistics. 6th Ed. Pearson Education Limited. Edinburgh, UK. 1056 pp, 2014.

Tanaka S, Kitamura T, Nakano H. Identification of shark species by SEM observation of denticle of shark fins. Collective Volume of Scientific Papers ICCAT, 54: 1386–1394, 2002.

Tukey J. Comparing individual means in the analysis of variance. Biometrics, 5(2): 99–114, 1949.
doi: 10.2307/3001913

Valenzuela A, Bustamante C, Lamilla J. Morphological characteristics of five bycatch sharks caught by southern Chilean demersal longline fisheries. Scientia Marina, 72(2): 231–237, 2008.
doi: 10.3989/scimar.2008.72n2231

Van Dykhuizen G & Mollet HF. Growth, age estimation and feeding of captive Sevengill Sharks, Notorynchus cepedianus, at the Monterey Bay Aquarium, Marine and Freshwater Research, 43(1): 297, 1992.

Wen L, Weaver JC, Lauder GV. Biomimetic shark skin: design, fabrication and hydrodynamic function, Journal of Experimental Biology, 217(10): 1656–1666, 2014.
doi: 10.1242/jeb.097097

Wilcoxon F. Individual comparisons by ranking methods, Biometrics Bulletin, 6(1): 80–83, 1945.
doi: 10.2307/3001968
How to Cite
Kanagusuku, K., Dufflocq, P., Sánchez-Rea, A., Huamantinco, A. A., & Ramírez-Amaro, S. (2021). Morphological characterization of dermal denticles of the Broadnose Sevengill Shark Notorynchus cepedianus (Elasmobranchii: Hexanchidae). Universitas Scientiarum, 26(3), 261–279.
Biología Celular, Fisiología, Morfología