Geometric Morphometric Description of the Body Shapes of the "Porang" Fish, Rasbora Sp., an Endemic Fish Species in Lake Wood, Zamboanga Del Sur, Mindanao, Philippines

Mary Ann M. Ganzon, Cesar G. Demayo


Biological descriptions of body shapes in fishes were commonly based on qualitative methods. However, with advances in imaging, geometry and statistics, descriptions of biological shapes have become more quantitative. Landmark-based geometric analysis is a new approach that has become more popular in analysing biological shapes thus was used in this study of an endemic fish species that can be found in a lake in Mindanao, Philippines. A total of 47 females and 104 male fishes were collected and digitized using 20 anatomical landmarks of the fish body. The digitized landmarks were Procrustes-fitted and were subjected to relative warp analysis (RWA). Relative warp scores were also subjected to Canonical Variate Analysis (CVA). RWA revealed within and between sex variations in body shapes. Male fish head is shorter and broader resulting to shorter length of the mouth from the snout tip to the posterior extremity of the premaxillar. Deeper body depth has also been viewed resulting to shorter standard length and longer and narrower tail region, while females have broader and elongated head regions having lengthy eye margins, extensive length between posterior insertion of anal fin and ventral points of the maximum curvature of the peduncle and mouth part are observed to have elongated distance between the snout tip and the posterior extremity of the premaxilla. These variations in shapes were observed in the two sexes, statistical analysis also has demonstrated that the shape variance between sexes in both left and right orientation of the body were significant. This means that the variations observed within sexes are sufficient to explain that the variations are associated to sex. Other characters aside from body shapes maybe are associated with sexual differences and should be further explored.


Landmark-based geometric analysis; Endemic fish; Body shape; Relative warp scores; Canonical variate analysis

Full Text:



D.C. Adams, F.J. Rohlf and D.E. Slice, Journal of Zoology 71, 5 – 16 (2004).

A.V. Badyaev, G.E. Hill, A.M. Stoehr, P.M. Nolan and K.J. McGraw, Evolution 54, 2134 – 2144, (2000).

F.L. Bookstein, IEEE Trans. Patt. Anal. Mach. Intell. 11, 67 – 585 (1989).

F.L. Bookstein, Cambridge University Press (1991).

F.L. Bookstein, Med. Image Anal. 1, 225 – 243 (1997).

M.E. Douglas, M.R. Douglas, J.M. Lynch and D.M. McElroy, Copeia 389 – 400 (2001).

Ø. Hammer, K.E. Webb and D. Depreiter, Geo-Marine Letters 29, 269 – 275 (2009).

C.C.D. Joseph, J.H. Jumawan, B.J. Hernando, L.Z. Boyles, J.C. Jumawan, J.P.B. Velasco, C.C. Cabuga, S.O.M.A. Abastillas, E.A. Requieron and M.A.J. Torres, Computational Ecology and Software 6(2), 55 – 65 (2016).

C.P. Klingenberg, M. Barluenga and A. Meyer, Biological Journal of the Linnean Society 80, 397 – 408 (2003).

P.M. Kocovsky, J.V. Adams and C.R. Bronte, Transactions of the American Fisheries Society 138, 487 – 496 (2009).

K.J. Parsons, B.W. Robinson and T. Hrbek, Environmental Biology of Fishes 67, 417 – 431 (2003).

J.T. Richtsmeier, V.B. Deleon and S.R. Lele, Yearbook of Physical Anthropology 45, 63 – 91 (2002).

F.J. Rohlf, TPSRELW v.1.45, Department of Ecology and Evolution, State University of New York at Stony Brook. (2007).

F.J. Rohlf, tpsDigit v.2.12, Free software available at the web page: (2008).

M.A. Spoljaric and T.E. Reimchen, Journal of Fish Biology, (2006).

J. Trapani, Environmental Biology of Fishes 68, 357 – 369 (2003).

C. Turan, Tropical Journal of Zoology 259 – 263, (1999).


eISSN 0975-5748; pISSN 0974-875X