The genus Pseudojuloides constitutes a collection of fusiform torpedo shaped wrasses with chisel like incisiform teeth that are more often found living in lose sandy rubble instead of the usual coral cover. Pseudojuloides was last revised in 1981 where five new species were added to the original three. Since then, the genus has been growing steadily with the description of Pseudojuloides kaleidos, P. severnsi and P. edwardi in 1995, 2000 and 2014 respectively. In March this year, Pseudojuloides polackorum was described from specimens in South Africa, making it the twelfth member of this expanding genus. The group now holds thirteen, with the newest Pseudojuloides zeus being indoctrinated from Micronesia.
Like P. edwardi and P. polackorum, P. zeus is more well known in the aquarium trade than in science. No photos of this species exists in the field, and the fish is known from only two specimens; the type from Majuro, Marshall islands, and a paratype from 80m (260 ft), Palau. Jason Edward from Greenwich has had a remarkable involvement in the description of all three species, being instrumental in supplying specimens needed for studies. P. edwardi was named in honour of him, and P. zeus was described in a paper which he co-authored.
Males are chartreuse on the anterior half before fading into a darker shade posteriorly. A pair of capri blue lines with iridescence run parallel, albeit jaggedly, equatorially along the body and terminates at the caudal peduncle. The caudal fin is mostly black with a hyaline post-marginal band. The dorsal fin is of the same color as the body anteriorly, and is separated from the hyaline posterior by a large mid-dorsal spot.
The specific epithet “zeus” was given after the Greek god of the same name, who had a penchant for casting lightning bolts on unsuspecting mortals. The pair of jagged blue lines seen in this species resembled said bolts of the unyielding Zeus.
Pseudojuloides zeus is deepwater, being found at depths ranging from 60-90m (200-300 ft). The holotype was collected from Majuro, Marshall Islands, and the paratype from Ngemelis Island in Palau. Outside of these two locales, it has been seen in Kwajalein, and it probably spreads further, albeit still restricted, into the Micronesian island chains, well beyond the continental influence of the Coral Triangle. The males of this species are particularly beautiful, and are most closely related to Pseudojuloides mesostigma (these two form a cladistic pair).
Both species are allopatric in distribution, with P. mesostigma being found in slightly shallower waters. They share the same extremely slender body profile, black caudal fin, dorsal spot (blotch in P. mesostigma) and iridescent body markings (although these are not organised into neat stripes in P. mesostigma). The female form of P. zeus is not known, but it is very likely uniform orange like those of P. mesostigma and many others in the same genus.
The fish is rarely collected for the aquarium trade, but when it does, it always commands a hefty price. This species is described by Benjamin Victor and Jason Edward in the Journal of the Ocean Science Foundation, volume 15. For more information, a link to the paper is provided below.