Panamic Slipper Lobster, Evibacus princeps

Panamic Slipper Lobster, Evibacus princeps, Juvenile. Length: 5.0 cm (2.0 inches). Provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, November 2017.

Phylogeny:  The Panamic Slipper Lobster, Evibacus princeps (Smith, 1869), is a member of the Scyllaridae family of Slipper Lobsters. The genus Evibacus is one of nineteen genera in this family, and there is only one species in this genus. They are also known as the Galapagos Slipper Lobster and the Shield Fan Lobster and in Mexico as Langosta Pantufla and Langosta Cigarra Chata.

Morphology:  Panamic Slipper Lobsters have 5 head segments, 8 thoracic segments, and 6 abdominal segments. The head and thorax are combined as a cephalothorax. They have five pairs of appendages that function as legs (pereiopods). One of these pairs is modified into enlarged pincers (chalae). They also have three pairs of appendages that function as mouth parts (maxillipeds). They have six pairs of biramous (dividing to form two branches) appendages along their abdomen. The first five pairs function as swimmerets (pleopods). The last pair is flattened to form a tail fan. The body is somewhat flattened dorso-ventrally. Their exoskeleton is thick and strong. Panamic Slipper Lobsters have two sets of antennae- a small pair for sensing their environment, and a large pair flattened to function as shields. Panamic Slipper Lobsters look somewhat like a disk, with a tail attached. The carapace is sculpted with bumps and nodules. The margins of the carapace and antennae are crenulated. They may be yellowish brown, tan, or reddish brown in color. Panamic Slipper Lobsters reach a maximum of 35 cm (14 inches) in length.

Habitat and Distribution:  Panamic Slipper Lobsters are found on soft substrates, such as sand or mud. They occasionally venture onto rocks. They can burrow to avoid predators. They are found at depths from 2 m (6 feet) to 90 m (295 feet). Panamic Slipper Lobsters are an Eastern Pacific species. In Mexican waters they are found throughout the Gulf of California, and range south along the mainland to Guatemala. They are absent from the West coast of the Baja Peninsula.

Diet:  Panamic Slipper Lobsters are opportunistic omnivores, consuming algae, crustaceans, echinoderms, mollusks, polychaetes, sea squirts, sponges, and sea squirts.

Predators:  Panamic Slipper Lobsters are primarily preyed upon by fish.

Reproduction: Panamic Slipper Lobsters are gonochoric (male or female for life). They reproduce sexually, with external fertilization. During mating the male attaches a sperm packet (spermatophore) to the abdomen of a female. The females releases tens of thousands of eggs, which are fertilized by the spermatophore. The female carries the fertilized eggs on her underside until, two weeks later, they hatch in to planktonic larvae. After several months the larvae settle to the bottom substrate to begin their benthic life. Less than 0.1% of the larvae survive to begin benthic life, and less than 1% of those survivors make it to adulthood.

Ecosystem Interactions:  Panamic Slipper Lobsters are known to host cirripede barnacles as epibionts. Otherwise, there is very little documentation of commensal, parasitic, or symbiotic relationships for this species.

Human Interactions: Panamic Slipper Lobsters are edible, but not commercially harvested. Beyond that, they have very limited direct impact on human activities. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:  None.