(Figure 4F)
Material examined
1 colony, polyp; Salvatierra Wreck, La Paz Bay, Baja California Sur, 24.384°N, 110.294°W; depth 18 m; 11 July 2019; on pagurid hermit crab; photograph.
Description (after Cairns and Barnard 1984)
Corallum encrusting a gastropod shell that encloses and protects a pagurid hermit crab. The hydroid colony bears five calcified branches, slightly curved, which radiate outward from the peripheral whorl of the gastropod shell.
Distribution
In the Mexican Pacific, the species has been reported from Baja California, Baja California Sur, Sonora, Sinaloa, Nayarit, and Jalisco (Stechow 1962; Cairns and Barnard 1984; Miglietta et al. 2009).
Remarks
The record of J. mirabilis arises from an underwater photograph; hence, the morphological details of the polyps at the microscopic level were not observed. However, J. mirabilis is a monotypic species (Cairns and Barnard 1984; WoRMS Editorial Board 2023), confirming the photographic record.