Elemental classification of the tusks of dugong (Dugong dugong) by HH-XRF analysis and comparison with other species

Abstract

The elemental composition was investigated and applied for identifying the sex and habitat of dugongs, in addition to distinguishing dugong tusks and teeth from other animal wildlife materials such as Asian elephant (Elephas maximus) tusks and tiger (Panthera tigris tigris) canine teeth. A total of 43 dugong tusks, 60 dugong teeth, 40 dolphin teeth, 1 whale tooth, 40 Asian elephant tusks and 20 tiger canine teeth were included in the study. Elemental analyses were conducted using a handheld X-ray fluorescence analyzer (HH-XRF). There was no significant difference in the elemental composition of male and female dugong tusks, whereas the overall accuracy for identifying habitat (the Andaman Sea and the Gulf of Thailand) was high (88.1%). Dolphin teeth were able to be correctly predicted 100% of the time. Furthermore, we demonstrated a discrepancy in elemental composition among dugong tusks, Asian elephant tusks and tiger canine teeth, and provided a high correct prediction rate among these species of 98.2%. Here, we demonstrate the feasible use of HH-XRF for preliminary species classification and habitat determination prior to using more advanced techniques such as molecular biology.

Age relationships with telomere length, body weight and body length in wild dugong (Dugong dugon)

“…In nature, wild dugongs may not have access to as much seagrass or quantities of food available to captive dugongs. Density of dugongs in the habitat also may affect growth rates due to influences on food availability and habitat quality ( Marsh, 1980 ; Nganvongpanit et al, 2017a , 2017b ), which in turn could affect age of sexual maturity. Population differences in age at sexual maturity have been observed in wild dugongs.…”

As, Cr, Hg, Pb, and Cd Concentrations and Bioaccumulation in the Dugong Dugong dugon and Manatee Trichechus manatus: A Review of Body Burdens and Distribution

“…In bone tissues, Nganvongpanit et al [64] analysed different parts of the fangs from D. dugon (crown, root, superficial, intermediate and medial tusk), showing similar percentages among the tusk parts, ranging from 0.008 ± 0.001% in medial and intermediate tusk, up to 0.015 ± 0.026% in the crown tusk (Table S8).…”

“…These are: Ag, Al, As, B, Ba, Be, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Pt, S, Sb, Se, Si, Sn, Sr, Ti, Tl, U, V, W, Zn and Zr. Whole blood is the matrix with the highest number of trace elements analysed [39,62,63], followed by some studies in bones, liver, kidney and muscles [40,64,65,66,67,68,69]. This paper focuses on the five elements of significant toxicological relevance: As, Cd, Cr, Hg and Pb, which are considered a threat to marine mammals [70], have been reported in Sirenia, and have also been related to the recent deaths in Tabasco.…”

“…In Sirenia, chromium has been analysed primarily in bone and liver tissues, and there are some kidney, muscle and skin reports in D. dugon and T. m. manatus [15,19,64,65,66,76,77]. There are also records for Cr concentrations in blood of T. manatus and T. m. latirostris of Florida, USA, and Brazil [39,62,78].…”

Table 4: Description statistics of linear regression models for body weight, body length and rTL in dugongs < or ≥20 years of age.

“…In nature, wild dugongs may not have access to as much seagrass or quantities of food available to captive dugongs. Density of dugongs in the habitat also may affect growth rates due to influences on food availability and habitat quality (Marsh, 1980;Nganvongpanit et al, 2017aNganvongpanit et al, , 2017b, which in turn could affect age of sexual maturity. Population differences in age at sexual maturity have been observed in wild dugongs.…”