Meilana L.1, Raj Kumar H.C.2, Taing V.2, Rasha Ahmad G.M.2, Abd Kadir N.H.3, Sheikh H.I.M.4, Chowdhury A.J.K.5, Shahimi S.3, Nelson B.R.2* 2024. Statistical method for Tachypleus gigas and Carcinoscorpius rotundicauda allometry // Invertebrate Zoology. Vol.21. No.2: 179–192 [in English].
1 Center for Coastal and Marine Resources Studies, International Research Institute for Maritime, Ocean and Fisheries, IPB University, Bogor, 16680, West Java, Indonesia.
2 Institute of Tropical Biodiversity and Sustainable Development, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
3 Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
4 Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
5 Faculty of Agriculture, Universiti Islam Sultan Sharif Ali, Simpang 347, Jalan Pasar Gadong, Bandar Seri Begawan, Brunei.
*Corresponding Author
Lusita Meilana lusitameilana@xmu.edu.cn ORCID 0000-0003-1674-383X
Harris C. Raj Kumar h240976@gmail.com
Vuthy Taing vuthy55@yahoo.com
Rasha Ahmed Ghaleb Moqbel rashaalhrazy79@gmail.com
Nurul Huda Abd Kadir nurulhuda@umt.edu.my ORCID 0000-0002-3263-9568
Hassan Ibrahim Sheikh Mohamed sheikh@umt.edu.my ORCID 0000-0001-6861-0647
Ahmed Jalal Khan Chowdhury ahmed.chowdhury@unissa.edu.bn ORCID 0000-0002-8115-2190
Salwa Shahimi salwa.shahimi@umt.edu.my ORCID 0000-0003-4722-4813
Bryan Raveen Nelson bryan.nelson@umt.edu.my ORCID 0000-0002-2461-5347
doi. 10.15298/invertzool.21.2.06
ABSTRACT: Morphology measurements could be used as a scale when converted into length-length or length-weight relationships. Size relationships could indicate variability for health and growth within horseshoe crab populations. However, in previous attempts, the selection of morphology units changed with every population. Basically, mean, and standard deviation was employed and median values became the baseline for normal classification. In this study, a linear equation was extracted for each morphology measurement. After inserting the mean values into the equation, a huge majority of Carcinoscorpius rotundicauda were within the normal or enlarged size scale. The similar was achieved for Tachypleus gigas except for the female group in which more crabs were indicated with normal body size. Comparatively, a greater number of males were scaled in the larger range. Meanwhile for other tests, the morphology measurements were square-root transformed. Resemblance was used to obtain a mirror expression for the transformed data. Draftsman plot revealed the data scattering while Link Tree analysis indicated dependable measurements and their range for allometry. Then, stepwise regression was employed and only matching variables were selected. Hence, the measurement units because reduced by 50%. This practice was generally introduced to minimize the management of large datasets. Therefore, the telson, prosoma length and opisthosoma width were selected for male horseshoe crabs whereas prosomal length was replaced with interorbit distance for the female crab. In relation to obtaining a huge majority of samples in the normal and positive allometry category, northern shores of Java could be indicated with sufficient resource supply. This study highlights revision in mean values which could become baseline for each morphology measurement during the assessment of allometry in populations of Java, Indonesia.
KEY WORDS: morphology; arthropod; linear; population; size.