A facultative anaerobe, alkalitolerant, gramnegative marine bacterium strain LBS5(T), was isolated from eggs carried on the pleopods of female spiny lobster (Panulirus penicillatus) in Andaman Sea from a depth of 3.5 m. Heterotrophic growth was observed at 15-38 degrees C and pH 5.5-11. Optimum growth occurred at 28 degrees C and pH 7.5. It can grow in the presence of 0.5-7 % NaCl (w/v), and the optimal NaCl required for growth was 2-4 %. 16S rRNA gene sequence analysis revealed the strain LBS5(T) belongs to the genus Photobacterium and showed 99.6 % similarity with P. aquae AE6(T), 98.2 % with P. aphoticum M46(T), 97 % with P. rosenbergii CC1(T), 96.9 % with P. lutimaris DF-42(T), and 96.6 % with P. halotolerans MACL01(T). The DNA-DNA similarities between strains LBS5(T) with other closely related strains were well below 70 %. The DNA G + C content was 50.52 (+/- 0.9) mol%. The major fatty acids were C16: 1w7c/w6c, C18: 1w6c/w7c, C16: 0, C15: 0 iso, C16: 0 10-methyl/17: 1 iso w9c, C17: 0 iso. Polar lipids included a phosphatidylglycerol, a diphosphatidylglycerol, a phosphatidylethanolamine, and one unidentified lipid. Based on the polyphasic evidences, strain LBS5(T) represents a novel species of the genus Photobacterium for which Photobacterium panuliri sp. nov. is proposed. The type strain is LBS5(T) (= DSM 27646(T) = LMG 27617(T) = JCM 19199(T)).