Population Structure and Shell Morphometrics of the Gastropod Theodoxus macri (Neritidae: Prosobranchia) from Azraq Oasis, Jordan
2006
Ali Z. Elkarmi | Naim S. Ismail
A total of 371 specimens of the freshwater gastropod Theodoxus macri (Sowerby, 1849) (Neritidae: Prosobranchia) from Azraq Oasis, Jordan, were studied for age, growth and shell morphometrics. The results show the life span to be four years. The mean observed lengths of the four age cohorts range from 3.295 to 7.707 mm. Theoretically, using Von Bertalanffy`s and Richard`s growth formulae, the maximum length of this snail may reach 17.187 and 12.930 mm, respectively. Shell and dry body weights averaged 44.4 and 36.05 mg, respectively. The relationships of the shell length to shell and dry body weights are curvilinear. However, the relationships of the shell length to shell width, aperture length and aperture width are linear. The relative coefficient (Kn) was 1.008 and 0.999 for young (age groups 1-2) and old (age groups 3-4) snails, respectively.
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