Tripneustes gratilla elatensis Dafni 1983

30.12.2019 27°42'11.57"N  34° 7'40.90"E Beacon Rock Dunraven, nightdive  

31.12.2018 24°41'29.85"N 35° 8'48.64"E Wadi el Gamal Dahra, nightdive 2 individuals  

02.01.2019 24°22'35.07"N 35°23'21.63"E Suil island, nightdive  

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.

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.

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).

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.

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