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30.12.2019 27°42'11.57"N 34° 7'40.90"E Beacon Rock Dunraven, nightdive
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31.12.2018 24°41'29.85"N 35° 8'48.64"E Wadi el Gamal Dahra, nightdive 2 individuals
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02.01.2019 24°22'35.07"N 35°23'21.63"E Suil island, nightdive
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This subtidal aggregation of T.g.elatensis demonstrates the high color variablity within this subspecies. Coloration of spines, tube-feet and pedicellaria ranges between white and black with no dominance of any color combination. to protect against high light intensity and camouflage they carry pebbles and sea-grass leaves.
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A living T. g. elatensis showing Type B pollution-induced deformity in Eilat, Red Sea: It showed mainly as an extreme apical collapse . It was apprently caused by chemicals ejected from a hotels laundry into an artificial lagoon. 2/3 of the population showed this deformity. This deformity was described by Dafni (1983b). It is still shown occasionally in small shore streches, apparently affected by polluted waters.
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Tests of Red Sea T. g. elatensis showing the rather smooth appearance of the test. arrows show the paucity of spine tubercles - less than 1 spine for each interambulacral plate (most oceanic Tripneustes - T. gratilla, T. depressus and T. ventricosus - all show at least one primary spine for each plate). The wide space between the ambulacra is densely covered by pedicellaria, which are poisonous the a certain degree (some people become allergic to it).
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Type A Deformed test of a T.g.elatensis showing exaggerate vertical growth, and "pinched" ambulacra, simultaneusly in all five ambulacra. A detailed descriotion of these deformities is shown in Dafni, 1980 and in Dafni & Erez 1987a,b.
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Type A deformity idue to pollution in T. g. elatensis in Eilat, Red Sea: It showed mainly as exaggrated H/D ratio. Here, a living urchin of ca 35 mm diameter, showed H/D = 1.2 proportion. This deformity was shown by over 1/2 of the population of T. g. elatensis in the shore next to the outfall of hot and saline seawater ejected from a combined power and desalination plant. Another picture shows the dried out test of a similar deformed urchin showing a skeletal abnormality such as "pinched" ambulacra, simultaneusly in all five ambulacra. A detailed descriotion of these deformities is shown in Dafni, 1980 and in Dafni & Erez 1987a,b
