The external morphology of the whitespotted whipray Himantura gerrardi (Gray, 1851)

Lee, Hui Xian (2015) The external morphology of the whitespotted whipray Himantura gerrardi (Gray, 1851). Universiti Malaysia Sabah. (Unpublished)

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Abstract

The Whitespotted Whipray Himantura gerrardi is presently known to be a cryptic species. This means that it has more than one species lumped under the same scientific name, it is also grouped into the 'Liarnacoids' species complex. The Whitespotted Whipray is an important commercial species, as it is one of the abundant species caught in the fisheries. The objective of this study is to obtain external morphological data of Whitespotted Whipray, Himantura gerrardi collected and to compare the colour variation between female and male, and between the four life stages (embryo, immature, maturing, and mature). This study follows standard morphometric and meristic methods to obtain the data. The specimens were collected from the Kota Kinabalu, SAFMA, fish market. A total of 36 specimens where examined; 21 specimens were purchased and measured in the lab whereas 15 specimens were examined on field. Meristic data showed dimorphic characters, useful for describing ontological characteristics. The results indicated no sexual dimorphic characteristics. There are three types of variation in the degree of spotting on the dorsal surface (low, medium and high); low degree shows spots only congregated at the posterior end of disc, with <20 spots; Medium degree have >20 spots and distributed at the posterior half of the disc; High degree have spots distributed across the posterior to the anterior of the disc. Individuals with low degree of spotting are speculated to be of another subspecies or species. There are two types of spot morphology seen (elongated clusters of spots with 'C' or '0' shape and solid round spots). The findings may be useful to Identify possible subspecies or new species, and provides useful Insight to Himantura gerrardi species complex. Internal anatomical characters and DNA sequence analysis could be carried out for future research.

Item Type: Academic Exercise
Uncontrolled Keywords: Whitespotted Whipray, colour variation, life stages, morphometric, meristic methods
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: FACULTY > Faculty of Science and Natural Resources
Depositing User: Munira
Date Deposited: 20 Nov 2017 02:05
Last Modified: 20 Nov 2017 02:05
URI: http://eprints.ums.edu.my/id/eprint/17349

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