Morphological characterization of dermal denticles of the Broadnose Sevengill Shark Notorynchus cepedianus (Elasmobranchii: Hexanchidae)

Keny Kanagusuku, Pablo Dufflocq, Angie Sánchez-Rea, Ana A. Huamantinco, Sergio Ramírez-Amaro

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Translated title of the contributionCaracterización morfológica de los dentículos dérmicos del tiburón de siete agallas Notorynchus cepedianus (Elasmobranchii: Hexanchidae)
Original languageEnglish
Pages (from-to)261-279
Number of pages19
JournalUniversitas Scientiarum
Volume26
Issue number3
DOIs
StatePublished - 2021

Bibliographical note

Funding Information:
This work was partially funded by Fondo Semilla 2018 (RDN ° 01-DGIDI-CIENTÍFICA-2018/ CRN ° 002-2018-PRO5) of the Universidad Científica del Sur. We thank the Laboratorio de Investigación and Laboratorio de Ecología Marina of the Universidad Científica del Sur for allowing us use laboratories, equipment and material (Aponte H, Indacochea A, López E, Obeso H, Caldas F.). We also thank the Banco de Germoplasma of the Instituto del Mar del Perú - IMARPE (Aguilar C, Tenorio C, Hernández H, Sánchez PPA, Arakaki N, Aguirre M.) for the provided support in the laboratory and the stereoscope usage. Furthermore, we want to thank to the students who collected some samples (Kohatsu S, Valderrama M, Indacochea A, Vitor M.) and processed skin samples (Gonzales G, Arévalo A.). We also want to thank Vitor M. for N. cepedianus picture provided and Laguna L. for drawing the illustrations of the denticles. Sergio Ramírez-Amaro is funded by a post-doctoral contract from the regional government of the Balearic Islands, co-funded by the European Social Fund 2014-2020. Finally, this study is part of the CRN 002-20018-PRO5 project and the MSc dissertation project of Keny Kanagusuku.

Funding Information:
Citation: Kanagusuku K, Dufflocq P, Sánchez-Rea A, Huamantinco AA, Ramírez-Amaro S. Morphological characterization of dermal denticles of the Broadnose Sevengill Shark Notorynchus cepedianus (Elasmobranchii: Hexanchidae), Universitas Scientiarum, 26(3): 261–279, 2021. doi: 10.11144/Javeriana.SC26-3.mcod Funding: This work was partially funded by Fondo Semilla 2018 (RDN ° 01-DGIDI-CIENTÍFICA-2018/CRN ° 002-2018-PRO5) of the Universidad Científica del Sur.

Funding Information:
This work was partially funded by Fondo Semilla 2018 (RDN ? 01-DGIDI-CIENT?FICA-2018/ CRN ? 002-2018-PRO5) of the Universidad Cient?fica del Sur. We thank the Laboratorio de Investigaci?n and Laboratorio de Ecolog?a Marina of the Universidad Cient?fica del Sur for allowing us use laboratories, equipment and material (Aponte H, Indacochea A, L?pez E, Obeso H, Caldas F.). We also thank the Banco de Germoplasma of the Instituto del Mar del Per? - IMARPE (Aguilar C, Tenorio C, Hern?ndez H, S?nchez PPA, Arakaki N, Aguirre M.) for the provided support in the laboratory and the stereoscope usage. Furthermore, we want to thank to the students who collected some samples (Kohatsu S, Valderrama M, Indacochea A, Vitor M.) and processed skin samples (Gonzales G, Ar?valo A.). We also want to thank Vitor M. for N. cepedianus picture provided and Laguna L. for drawing the illustrations of the denticles. Sergio Ram?rez-Amaro is funded by a post-doctoral contract from the regional government of the Balearic Islands, co-funded by the European Social Fund 2014-2020. Finally, this study is part of the CRN 002-20018-PRO5 project and the MSc dissertation project of Keny Kanagusuku.

Publisher Copyright:
© 2021

Keywords

  • Peru
  • Peru
  • Perú escama placoidea
  • descripción
  • description
  • descrição
  • escala placoidea
  • identificación taxonómica
  • identificação taxonômica
  • placoid scale
  • taxonomic identification

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