Liopropoma incandescens, Pinheiro, Hudson T., Shepherd, Bart, Greene, Brian D. & Rocha, Luiz A., 2019

Pinheiro, Hudson T., Shepherd, Bart, Greene, Brian D. & Rocha, Luiz A., 2019, Liopropomaincandescens sp. nov. (Epinephelidae, Liopropominae), a new species of basslet from mesophotic coral ecosystems of Pohnpei, Micronesia, ZooKeys 863, pp. 97-106 : 99-101

Liopropoma incandescens sp. nov. Figures 1, 2 Incandescent Basslet

Type locality.

Ant Atoll, Pohnpei, Micronesia.

Holotype.

CAS 246199, 54.15 mm SL, Federated States of Micronesia, Pohnpei, Ahnd (Ant) Atoll, west side, 6.75589N, 157.91933E, 29 August 2017, B. D. Greene, hand nets, 130 m depth.

Diagnosis.

Liopropoma incandescens sp. nov. can be distinguished from all of its congeners by the yellow to orange body color (Figure 1A), with two distinctive black blotches on the upper and lower caudal fin lobes (Figure 1A, B), and by the following combination of characters: dorsal fin VIII,13; anal fin III, 9; pectoral fin 14; total gill rakers on first arch 15; lateral-line scales 62; length of first dorsal-fin spine 5% SL; depth at origin of dorsal fin 22% SL; least depth of caudal peduncle 15% SL; orbit diameter 9% SL.

Description.

Dorsal-fin rays VIII, 13 (spines not embedded into the skin, and the last two soft rays are associated with a single complex pterygiophore; Figure 1C); anal-fin rays III, 9 (last two soft rays associated with a single complex pterygiophore); pectoral-fin rays 14, dorsal-fin-most ray unsegmented; pelvic-fin rays I, 5; principal caudal-fin rays 8+7=15; rudimentary and procurrent caudal-fin rays 10+9=19; pored lateral-line scales 62; scales from lateral line to dorsal fin origin 6; scales from lateral line to anal fin origin 22; gill rakers on first arch, including rudiments, 6+9; vertebrae 8+15 (Figure 1C).

Measurements presented as percentage of standard length (SL): body depth at origin of dorsal fin 21.8; body width just behind gill opening 14.9; head length 38; snout length 9.5; orbit diameter 8.6; bony interorbital width 6.4; upper-jaw length 14.7; maxillary length 12.7; least caudal-peduncle depth 14.6; caudal-peduncle length 13.5. Fin lengths: dorsal-fin spines: (I) 4.6; (II) 9.9; (III) 10.7; longest dorsal-fin soft ray the 10th, length 17.4; lengths of anal-fin spines: (I) 3.9; (II) 10.1; (III) 11.3; longest anal soft ray the 5th, length 18.1; caudal-fin length 23.2; pectoral-fin length 26, fin short, not reaching vertical between anus and dorsal fin; pelvic-fin length 19, fin reaching vertical slightly posterior to base of 5th dorsal-fin spine.

Interorbital region flat; mouth oblique, maxilla almost reaching vertical crossing posterior border of pupil; prominent bony projection on posteroventral corner of maxilla; lower jaw projected. Anterior nostril in thin, membranous tube, situated close to tip of snout; posterior nostril a simple opening, situated close to orbit. Lateral line strongly arched above pectoral fin, highest point below fourth dorsal-fin spine. Trunk covered with ctenoid scales, scales becoming weakly ctenoid anteriorly and cycloid on head. Head fully scaled except over branchiostegal area. Short membrane covered by scales anteriorly to first dorsal-fin spine, six rows of scales covering basal anterior portion of soft dorsal fin, decreasing uniformly to two scales at posterior basal portion of soft dorsal fin. Anal fin with two to five rows of scales basally (more rows between second and fourth spine. Caudal fin almost completely scaled, except for distal tips of rays. Scales present on pectoral-fin base, pelvic-fin base, and on proximal portion of pelvic fin. Jaw teeth small; upper and lower jaws with bands of villiform teeth, bands slightly wider anteriorly. Vomer oval patch of small teeth. Palatines with several rows of small teeth in long and narrow bands at each side of mouth. Opercle with one conspicuous middle spine. Margin of upper and lower limb of preopercle smooth.

Color in life.

Alive and freshly euthanized holotype (Figures 1A, 2) with coloration as follows: snout, top of head and trunk yellow, grading to vivid orange on a diagonal around upper two-thirds of body to caudal fin. Pale pink checks with yellow blotches behind eye, on operculum, and on dorsal-most part of body from head to base of soft dorsal fin. Indistinct orange line from tip of snout, across top of eye, continuing to above preopercle edge. Pupil black with yellow outer margin; eye pale purple and orbit with orange ring along margin. Pale pink-orange to peach-colored throat, continuing below pectoral fins, and across belly. Dorsal fin with yellow-orange tipped spines and mostly translucent inter-spinous membranes; base of soft dorsal-fin rays (ventral third, scaled region) orange; soft dorsal fin central upper region yellow from first to eighth ray; margin of the first soft dorsal-fin ray orange, transitioning to white from second to eighth; dorsal portion between eighth and twelfth soft ray light orange, with no white margin and no yellow. Pectoral fin light orange, yellow anteriorly (first ray). Upper two-thirds of anal fin orange, distal region yellow from second to ninth ray; anal-fin margin white along second to ninth ray with a pale orange sub-border, translucent along tenth to twelfth ray. Central portion of caudal fin with orange rays and membranes, with white pigments in the distal posterior third; upper and lower portions of caudal fin yellow with orange base; two pronounced oval-shaped black spots with posterior white margins, approximately the same size as orbit, on outer upper and lower caudal lobes.

Color in alcohol.

In alcohol (Figure 1B), body light beige, pigment only present on a small patch of yellow on the snout, and the two pronounced dark spots on distal upper and lower caudal fin lobes.

Distribution.

Liopropoma incandescens sp. nov. is known based on one specimen collected at a depth of 130 m in Ahnd (Ant) Atoll, Pohnpei, Federated States of Micronesia. The lack of records for the species in other MCEs of the Pacific Ocean is probably due to its cryptic habits combined with the lack of sampling at those depths across the wider region.

Habitat and behavior.

Liopropoma incandescens sp. nov. has a cryptic habit and was discovered and collected in a small rocky crevice along a steep limestone coral reef drop-off at a depth of 130 m (Figure 3). A second individual (~10 cm length) was sighted in the same area, together with species such as Tosanoides annepatrice Pyle, Greene, Copus & Randall, Centropyge abei Allen, Young & Colin, Odontanthias sp. and Roa sp., but was not collected.

Etymology.

The specific name is a noun in apposition from the Latin, incandescens , to glow. The vivid yellow to orange incandescent coloration of the species prompted us to select this name.

Comparisons.

The color of Liopropoma incandescens sp. nov. sets it apart from all other species in the genus: the gradient from yellow to orange and the two black spots on the upper and lower caudal fin lobes are unique. The only other species with black spots on upper and lower caudal fin lobes is Liopropoma carmabi (Randall), from the Western Atlantic, which has alternating orange and pink horizontal lines running from the snout to the caudal fin. Moreover, most species of Liopropoma have between 44 and 54 lateral-line scales, whereas L. incandescens sp. nov. shares a high number of lateral-line scales (62) exclusively with Liopropoma maculatum ( Döderlein) ( Randall and Taylor 1988, Kon et al. 1999, Wirtz and Schliewen 2012, Baldwin and Johnson 2014, Baldwin and Robertson 2014). Liopropoma incandescens sp. nov. differs from L. maculatum by the lower number of pectoral fin-ray counts (14 vs 15-16), the presence of two black spots on outer upper and lower lobes of the caudal fin, a more slender body (body depth 4.6 vs 3.2-4 in SL), and shorter snout (4 vs 3.3-3.7 in HL).