No abstract

No abstract

Blue crab Bardawil Lagoon Feeding habits Gastric mill Stomach contents of 161 specimens of Callinectes sapidus(Crustacea: Decapoda: Portunidae)from Bardawil Lagoon were examined from November 2016 to July 2017. The percentage point (% P) and percentage frequency of occurrence (% F) methods were used for stomach contents analysis. Out of the 161 individuals 75 (46.58 %) had empty stomach. Mollusca, Crustacea and Pisces dominated the diet of this species. According to points method Mollusca, Crustacea and Pisces scored 44.83%, 18.1% and 16.24% points in malesand 47.2%, 21.62% and 11.03% points in females, respectively. Consumed tissues of other benthic invertebrates were also present in verylow ratios, while algal fragments were occurred in low quantitiesin few stomachs. Sediments were also detected in considerable ratios. Results of the present study suggest that the blue crab C. sapidusis a carnivore. The remarkable seasonal fluctuations in the diet composition and stomach fullness of this species during the present studywere detected For understanding the mechanism of feeding, gastric mill structure was morphologically investigated and all its seven articulated ossicles were examined and photographically illustrated.

IntroductionWe describe the tagmatization pattern of the anterior region of the extant stomatopod Erugosquilla massavensis. For documentation we used the autofluorescence capacities of the specimens, resulting in a significant contrast between sclerotized and membranous areas.ResultsThe anterior body region of E. massavensis can be grouped into three tagmata. Tagma I, the sensorial unit, comprises the segments of the eyes, antennules and antennae. This unit is set-off anteriorly from the posterior head region. Ventrally this unit surrounds a large medial sclerite, interpreted as the anterior part of the hypostome. Dorsally the antennular and antennal segments each bear a well-developed tergite. The dorsal shield is part of tagma II, most of the ventral part of which is occupied in the midline by the large, partly sclerotized posterior part of a complex combining hypostome and labrum. Tagma II includes three more segments behind the labrum, the mandibular, maxillulary and maxillary segments. Tagma III includes the maxillipedal segments, bearing five pairs of sub-chelate appendages. The dorsal sclerite of the first of these tagma-III segments, the segment of the first maxillipeds, is not included in the shield, so this segment is not part of tagma II as generally thought. The second and third segments of tagma III form a unit dorsally and ventrally. The tergites of the segments of tagma III become progressively larger from the anterior to the posterior, possibly resulting from a paedomorphic effect during evolution, which caused this reversed enlargement.ConclusionsThe described pattern of tagmosis differs from current textbook knowledge. Therefore, our re-description of the anterior body area of stomatopods is of considerable impact for understanding the head evolution of Stomatopoda. Likewise, it has a bearing upon any comparisons with fossil stomatopods, as mainly sclerotized areas are fossilized, and, on a wider scale, upon larger-scale comparisons with other malacostracans and eucrustaceans in general.

he population of the portunid crab Charybdis natator in the Gulf of Suez, Red Sea was studied by monthly sampling from September 2007 to May 2008. Crabs were sexed, measured and berried females recorded. A total of 498 individuals were obtained, of which 232 (46.6%) were males, 212 non-ovigerous females (42.5%), and 54 (10.9%) ovigerous females. The overall sex ratio (M:F) was (1:1.1) and females outnumbered females during September-November. The population showed sex differences in the size frequency distributions, with males reaching larger size than females respectively). Ovigerous females existed all year round and ranged in size between 83-118.4mm CW. Fecundity ranged from 45230 to 335529 eggs per female and was positively correlated with body size. The effectiveness of the closed season that runs in the Gulf of Suez on the population of C. natator was discussed.