Morphology and age cohorts of Pachygrapsus marmoratus (Grapsidae) in the southern Mediterranean Sea (Published)
The aim of this work was to establish morphological traits of P. marmoratus inhabiting the rocky intertidal zone of the southern Mediterranean Sea coast. 457 P. marmoratus collected randomly from the AL-Haniyah, Al-Hamamah, and Susah sites, eastern Libya, during 2019 were used in the study. The largest carapace length (CL) and weight (WW) were 35.1cm and 31.0g, respectively, while the minimums were 8.50cm and 0.40g. The means were 24.5cm and 10.2g. The order of WW by season was: winter and spring > fall > summer; by site: Al-Haniyah > Susah > Al-Hamamah; males being heavier than females. The WW-CL relationship was WW=0.001*CL**2.817; R2=0.909. The condition factor of P. marmoratus was highest in spring and lowest in summer, highest in Al-Haniyah and Susah and lowest in Al-Hamamah, and similar for both sexes, it increased in a negative allometric manner as the crab grew. The morphometrical parameters of male P. marmoratus were higher than those of females. Most morphometrical parameters scored higher values in winter and spring, followed by fall, and summer, with Al-Haniyah and Susah parameters being higher than the Al-Hamamah ones. Temporal and spatial variations of the morphometric parameters were discussed in terms of the availability of food and prevailing environmental conditions. Regressions of females and males P. marmoratus morphometric parameters with CL were strong and positive. Bilateral dimorphism was not observed. Four-year age groups, +1 (11-12mm), +2 (16-18mm), +3 (25-26mm) and +4 (32-33mm), comprised the P. marmoratus population.
Citation: Ayiman Faraj Eisay, Hind Abdrabba Yousef, Sayed Mohamed Ali, Ramadan A. S. Ali (2022) Morphology and age cohorts of Pachygrapsus marmoratus (Grapsidae) in the southern Mediterranean Sea, International Research Journal of Natural Sciences, Vol.10, No.3, pp.14-32
Keywords: Libya., Mediterranean, Morphology, Pachygrapsus marmoratus, morphometry
Morphology of Phorcus turbinatus (Gastropoda) in the Eastern Libyan Mediterranean Sea (Published)
Three hundred and five Phorcus turbinatus collected from the rocky littorals of Al-Haneah and Susah, eastern Libya’s Mediterranean Sea, were used to establish 15 measured shell-parameters and 18 calculated shell-shape indicators, which were then compared between sites, and related to shell height (HBA) and length of shell base (LB) by regression equations to find out how they vary as the animal grows. Al-Haneah P. turbinatus was larger than Susah’s (HBA = 13.729 and 12.818mm consecutively, corresponding to total weights (TW) of 3.766 and 3.179gm). As a result, the majority of Al-Haneah’s P. turbinatus measured parameters were of greater magnitude. The exponents “b” of the TW-HBA power regressions indicated negative allometric growth, while that of TW-LB indicated positive allometry. The values of the shell shape indicators of P. turbinatus in both sites were close, the shell apex was tilted to the front and to the left, the shell base was almost circular, the opening was slightly oval, and the operculum was circular. All the measured parameters, and most of the shell-shape indicators, increased with growth.
Citation: Adam Ali Faidallah, Ramadan A. S. Ali, Sayed Mohamed Ali, (2021) Morphology of Phorcus turbinatus (Gastropoda) in the Eastern Libyan Mediterranean Sea, International Research Journal of Natural Sciences, Vol.9, No.1, pp.12-18
Keywords: Mediterranean Sea, Monodonta turbinata, Phorcus turbinatus, morphometry, shell shape