Green Spiny Lobster, Panulirus gracilis

Green Spiny Lobster, Panulirus gracilis. Lobster provided by the commercial fishermen of the greater Los Cabos area, February 2015. Length: 30 cm (12 inches).

Green Spiny Lobster, Panulirus gracilis. Underwater photograph taken in the greater Loreto area, Baja California Sur, October 2024. Photography courtesy of Bob Hillis, Ivins, Utah.

Phylogeny:  The Green Spiny Lobster, Panulirus gracilis (Streets, 1871), is a member of the Palinuridae Family of Spiny Lobsters. The genus Panulirus is one of twelve genera in this family, and there are twenty-two species in this genus. In Mexico this species is called langosta verde.

Morphology:  The head and thorax of Green Spiny Lobsters are fused together and covered by a carapace. The carapace is covered with short spines. Two longer spines extend over the eye stalks. The abdomen or tail is divided into overlapping segments, which allows it to bend while maintaining a protective exoskeleton. The tail fan consists of five flattened appendages. Green Spiny Lobsters have ten segmented legs and two spiny antennae. Spiny lobsters can move either by walking or, to make a quick escape, by quickly flexing their tail, causing them to rapidly swim backwards. Green Spiny Lobsters can be dark green, bluish, or grayish, with green or blue spines on the carapace. This species reaches around 30 cm (12 inches) in length. This species can be confused with other spiny lobsters in the region. It is distinguished from the Pinto or Blue Spiny Lobster, Panulirus inflatus, by its lack of white spots on the abdomen. It differs from the California Spiny Lobster, Panulirus interruptus, in its green/blue coloration and not reddish coloration. It differs from the Pronghorn-Socorro Spiny Lobster, Panulirus penicillatus, by its lack or yellow-orange spots on the tail appendages.

Habitat and Distribution:  Green Spiny Lobsters are found during the day hiding in cracks and crevasses in the reef. At night they head out across the reef and surrounding sandy areas looking for food. They live at depths of 3 m (10 feet) and 50 m (165 feet). In Mexican waters they are found along the entire Pacific coast south of Magdalena Bay. They are found in the southern half of the Gulf of California, though they are not common.

Diet:  Green Spiny Lobsters are nocturnal predators and scavengers. They eat carrion, crustaceans, detritus, echinoderms and mollusks.

Predators:  Adult Green Spiny Lobsters are prey for large fish, and octopuses and sea lions. Juveniles are also eaten by shore birds, crabs and small fish.

Reproduction:  Green Spiny Lobsters are gonochoric (male or female for life). They reproduce sexually, by transfer of a sperm packet from the male to the abdomen of the female. The female scratches open the sperm packet as she releases her eggs. The female carries the fertilized eggs on her abdomen until they hatch after a few weeks. The eggs hatch into planktonic larva. After several developmental stages the larva molt into benthic juvenile lobsters.

Ecosystem Interactions:  Parasitic, commensal, or symbiotic relationships have not been documented for the Green Spiny Lobster. However other species in this genus are known to host endoparasites such as: bacteria, cestodes, fungus, helminths, nemerteans, protists, trematodes, and viruses. Many of these parasites are found in lobsters kept in captivity. It is unknown how many of these organisms are found in wild lobsters. Ectoparasites include amphipods and copepods. Additionally, they may host fouling organisms like barnacles and algae.

Human Interactions:  Green Spiny Lobsters are targeted by commercial, artisanal, and recreational fisheries. They are considered an important food source and economic resource in the region. Overfishing of the species is a very real possibility in heavily fished areas though the data is insufficient to assess the risk to the total population.

Synonyms:  Palinurus brevipes, Palinurus martensii, and Palinurus paessleri.