Wednesday, June 5, 2019

[Ichthyology • 2019] Luzonichthys kiomeamea • A New Species (Serranidae: Anthiadinae) from A Mesophotic Coral Ecosystem of Rapa Nui (Easter Island)

Luzonichthys kiomeamea 
 Shepherd, Pinheiro, Phelps, Perez-Matus & Rocha, 2019

A new species in the anthiadine genus Luzonichthys Herre, 1936 is described from a specimen collected at a depth of 83 m in a mesophotic coral ecosystem at Rapa Nui (Easter Island). Luzonichthys kiomeamea n. sp. can be distinguished from the 7 other valid Luzonichthys species by anal-fin and pectoral-fin counts, the number of lateral-line scales, the number and arrangement of gill rakers, and coloration pattern. Mitochondrial DNA sequencing shows that the new species is more than 11% divergent in the COI sequence (and about equally distant) from Luzonichthys waitei, L. seaver, L. earlei (Hawai’i), and L. aff. earlei (Coral Sea). Given the isolation of the island, and the uniqueness of its fish fauna, we suspect that the new species is endemic to the mesophotic reefs of Rapa Nui.

 Key words: taxonomy, ichthyology, coral-reef fishes, endemism, South Pacific, Splitfin Anthias, Chile

Figure 1. Luzonichthys kiomeamea, sp. n., holotype, CAS 244640, 45.7 mm SL, shortly after death (L.A. Rocha).

Luzonichthys kiomeamea, n. sp. 
Rapa Nui Splitfin

Diagnosis. Dorsal-fin elements X,16; anal-fin elements III,7; pectoral-fin rays 22; lateral-line scales 64; gill rakers 12+26; body moderately elongate, depth 4.8 in SL; head length 3.6 in SL; snout 4.1 in HL; caudal fin forked and without filaments, length 4.3 in SL; caudal-fin concavity 6.3 in SL; pectoral-fin length 4.0 in SL; pelvic-fin length 5.0 in SL; color in life: body orange-red dorsally, silver-magenta ventrally, with alternating magenta, red, and orange lines along sides of body; dorsal fin yellow-orange with red-orange spots (Fig. 1).

Etymology. The specific epithet is from the Rapa Nui name; the phrase kio-meamea means “red fish that takes refuge in a cave”. Treated as a noun in apposition.

 Distribution and habitat. The new species is currently known only from Rapa Nui. The holotype was collected at a depth of 83 m in a rocky patch reef surrounded by a large sandy area (Fig. 4). It was caught by hand using hand nets and transported alive to the surface in a perforated-plastic collecting jar.

Figure 4. Luzonichthys kiomeamea in its natural habitat, 83 m, Hanga Piko, Rapa Nui (Easter Island), Chile (L.A. Rocha).

Bart Shepherd, Hudson T. Pinheiro, Tyler Phelps, Alejandro Perez-Matus and Luiz A. Rocha. 2019. Luzonichthys kiomeamea (Teleostei: Serranidae: Anthiadinae), A New Species from A Mesophotic Coral Ecosystem of Rapa Nui (Easter Island). Journal of the Ocean Science Foundation. 33; 17-27. 

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