Six marine bivalves species were recorded from the north west of the Arabian Gulf, Iraqi coast from 2020 to 2021. The species are Acar plicata (Dillwyn, 1817) (family Arcidae), Sunetta effossa (Hanley, 1843) (family Veneridae), Scissileda tropica (Melvill, 1897) (family Yoldiidae), Protapes cor (Sowerby, 1853) (family Veneridae), Circentia callipyga (Born, 1778) (family Veneridae) and Acrosterigma lacunosa (Reeve, 1845) (family Cardiidae). These records raise the number of marine bivalves known from the Iraqi coast to 38 species.

The annual O2 consumption, annual energy budget and the ecological efficiencies of a population of the barnacle Balanus amphitrite amphitrite were estimated in Garmat-Ali river, in the period October 1994-September 1995. The annual O2 consumption was 2156 kJ/ m2/yr, the rate of O2 consumption increased with increasing temperature and body weight, the barnacle consumes oxygen at a rate of 0.622 µlO2/mg/h at 15°C, 0.84 µlO2/mg/h at 23°C and 0.954 µlO2/mg/h at 30°C. The Q10 values increased with increasing size of barnacle. The food items provided were the alga, Chlorella sp. with a calorific contents of 3.2 kcal/g DW, and a flesh of the clam C. fluminea with 5.4 kcal/g DW. The barnacle assimilates the flesh of the clam about 7 times more than assimilating the Chlorella. The barnacle allocates 45-55% of the assimilated energy for net growth and 27-37% for metabolic energy expenditure, whereas 18% is channeled for faeces production. The respiratory coefficient (R/P) of this barnacle was 0.6. The assimilation efficiency for the plant and animal food were 88-91%. The annual energy budget equation for a population of barnacle at Garmat-Ali river is: Cp 16271.14 = Pp 11639.55 + Rp 2156 + Fp 2475.60.

Specimens of the epialtid crab. Hyastenus hilgendorfi De Man, 1887 were collected from intertidal and shallow subtidal of the Rass Al-Beshaa area of the Shatt Al-Arab in Al-Faw City, NW-Arabian Gulf. Specimens were collected by trawl net during November 2016. This represents the first record of the genus Hyastenus White, 1847 for Iraqi coast. The specimens are diagnosed and the taxonomy of the genus discussed.

In the present study, a Leucosiid crab Hiplyra sagitta (Galil, 2009), was found for the first time in the Iraqi coast, from the lower reaches of Shatt Al-Arab at Fao city, Basrah, Iraq, during November 2016. Diagnostic characters of the species are figured and its world geographical distribution, especially in the Persian Gulf region is considered.Keywords New records; Hiplyra sagitta; Decapoda BackgroundLeucosiidae is common family in the Arabian-Persian Gulf, Gulf of Oman and red sea. This is most diverse and distribution of all brachyuran families (Stephensen, 1946; Titgen, 1982; Apel, 2001 Naderloo andTürkay, 2012). Leucosiidae family formed about 16.6% of all brachyuran crab species of the Persian Gulf (Apel, 2001).Previous studies on the Persian Gulf brachyuran crabs are confined to Stephensen (1945), Basson et al. (1977), Titgen (1982), Jones (1986), Apel (1994), Cooper (1995), Al-Ghais and Cooper (1996), Bahmani (1997), Apel (2001), Naderloo and Sari (2007), Galil (2009), Gilil et al. (2012, Naderloo and Apel (2012) and Naderloo and Türkay (2012) have increased the number of reported leucosiid species to 37. The aim of the present paper deals with first record for Iraqi coast of Leucosiid crabs H. sagitta from fresh specimens collected from NW of the Arabian Gulf at Fao region and to add this species to the brachyuran crabs list of Iraqi waters. Materials and MethodsThe specimens of Leucosiid crabs H. sagitta were collected from intertidal and shallow subtidal zones of Iraqi coast at the Rass Al-Beshaa area from the lower reaches of the Shatt Al-Arab in Fao city, north-western Arabian Gulf (Figure 1) by hand and trawl net. Some physico-chemical parameters recorded from the study area during the collections made in November 2016 are: water temperature, 22.5°C; pH, 7.68; salinity, 34.5 psu; dissolved oxygen, 6.94 mg/L. The specimens of Leucosiid crabs H. sagitta were preserved in 70-80% alcohol and shipped to the laboratory of Marine biology Dep., Marine science Center, University of Basrah and deposited in the (MSC, 54).The specimens of this species were identified following: Galil (2009) DiagnosisCarapace (Figure 2A) discoidal, convex; dorsal surface finely punctate on branchial, cardial and intestinal regions, along branchio-cardiac grooves, and medially on gastric region.Anterolateral and posterolateral border covered with larger to smaller granules; front crescentic shaped nearly smooth; shallow anterior margin of efferent channel nearly straight, separated from lateral granulated margin by narrow U-shaped incision. lower margin bearing line of prominent granules. Abdominal segments 3-6, Male abdomen ( Figure 2B) elongate-triangular; telson completely smooth.Ischium of 3rd maxilliped slightly longer than merus, about 1.22 times merus length. Margins of fused male abdominal segments 2-6 distally carinate. Margins of fused abdominal segments in female minutely granulate ( Figure 2C).Chelipeds equal in size and shape; merus longer than total length of carapace, Male chelipeds ( Figure 2A) modera...

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