Plectranthias raki, Shepherd & Pinheiro & Najeeb & Rocha & Rocha, 2025

Plectranthias raki sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , Table 1 Dhivehi common name: Raki bureki English common name: Maldivian Perchlet View Table 1

Type locality.

Maldives.

Material examined.

Holotype. • CAS - ICH 248439 About CAS (Field number LAR 2951) 66.2 mm SL, GenBank PQ 416576. Location: Kuramathi Outer Reef , Rasdhoo Atoll, Maldives 4°15'22"N, 72°59'00"E, depth of collection 118 m, collected with hand nets by B Shepherd, HT Pinheiro, MV Bell, and LA Rocha, 9 December 2022 GoogleMaps . Paratype. • LACM 61827 About LACM (Field number LAR 2952) 70.4 mm SL, GenBank PQ 416577. Same collection data as holotype GoogleMaps .

Diagnosis.

Plectranthias raki sp. nov. is unique in both morphology and coloration. The following combination of characters distinguishes it from all known congeners: dorsal fin X, 15; anal-fin rays III, 7; pectoral-fin rays 13 | 13 (13 | 12), all unbranched; principal caudal-fin rays 9 + 8; lateral line complete with 30–32 tubed scales; 3 supraneural bones, predorsal formula 0 / 0 + 0 / 2 / 1 + 1 / 1 / 1 /; gill rakers 5 + 12; circumpeduncular scales 11–12; oblique rows of scales on cheek 8 (7); longest dorsal spine the 4 th or 5 th; no fleshy tips on the dorsal-fin spines; no antrorse serrations on preopercle. Live coloration consisting of a series of irregularly shaped patches of red-orange along dorsal two-thirds of body; patches divided into two indistinct rows by the lateral line; patches red-orange dorsally and posteriorly, becoming more yellow-orange anteriorly and ventrally, golden yellow on opercle and maxilla; anal fin pointed, mostly white proximally, yellow distally, with two yellow spots approximately one-third orbit diameter at base of third spine and fifth and sixth soft rays; two irregularly shaped yellow-orange spots, approximately one-third orbit diameter, located on either side of centermost caudal-fin rays; small orange spot, approximately one-half orbit diameter, at base of pelvic fin.

Description.

Dorsal rays X, 15, all segmented rays branched; anal rays III, 7, all segmented rays branched; pectoral-fin rays 13 | 13 (13 | 12), all unbranched; pectoral fin moderately long, longest ray reaching to vertical above midpoint of anal fin; pelvic-fin I, 5; upper procurrent caudal-fin rays 6; lower procurrent caudal-fin rays 4; principal caudal-fin rays 9 + 8; branched caudal-fin rays 9 + 7 (8 +?); lateral line complete with 32 (30) tubed scales on the left side; scales above lateral line to origin of dorsal fin 3; scales above lateral line to base of middle dorsal spine 2; scales below lateral line to origin of anal fin 10; oblique rows of scales on cheek 8 (7); circumpeduncular scales 11 (12); gill rakers 5 + 12, the upper 4 and lower 3 rudiments; pseudobranchial filaments 18 (15); branchiostegal rays 7. Vertebrae 10 + 16; supraneural (predorsal) bones 3; predorsal formula 0 / 0 + 0 / 2 / 1 + 1 / 1 / 1 /; dorsal pterygiophores in interneural spaces 9–13 1 / 1 / 1 + 1 / 1 + 1 / 1; no trisegmental pterygiophores associated with dorsal fin; terminal dorsal pterygiophore in interneural space 18; no trisegmental pterygiophores associated with anal fin; terminal anal pterygiophore in interhaemal space 5; ribs present on vertebrae 3 through 10; epineurals present on vertebrae 1 through 12 (possibly 13); parhypural and hypurals autogenous; well-developed hypurapophysis on parhypural; epurals 3; single uroneural (posterior uroneural absent); ventral tip of cleithrum with well-developed posteroventral process; proximal tip of first anal-fin pterygiophore near distal tips of parapophyses on vertebra 10.

Body moderately deep, the depth 2.7 in SL, and compressed, the width 2.2 in depth; head fairly short, 2.2 (2.1) in SL; dorsal fin originates at a vertical line just above the third lateral line scale; dorsal fin continuous and notched between the spinous and soft portions to about half of the length of the first soft ray; dorsal-fin spines without fleshy tabs on the tips; dorsal-fin base length 3.2 (2.1) in SL; the fourth and fifth dorsal spines the longest and the same length in the holotype (the fourth the longest on the paratype); third dorsal-fin soft ray the longest, with extended filament; anal-fin base length 6.0 (5.7) in SL; second anal-fin spine the longest; anal fin pointed with the third segmented ray the longest; pectoral fin moderately long and pointed, 2.9 (2.7) in SL; pelvic fin relatively short, 4.0 (4.2) in SL, and not reaching anus; caudal fin slightly emarginate, with several filaments on elongated ray branches (caudal fin in paratype damaged); caudal peduncle length 3.9 (5.1) in HL; caudal peduncle depth 3.7 (4.2) in HL.

Morphometric values are summarized in Table 1 View Table 1 .

Head of moderate size, 2.2 (2.1) in SL; snout pointed, 3.4 (3.9) in HL; mouth relatively large, terminal and oblique, the posterior margin of maxilla reaching to vertical line almost directly beneath the center of pupil; upper jaw length 2.3 (2.5) in HL; maxilla expanded posteriorly; upper jaw with one large canine on each corner; 5 irregular rows of villiform teeth, largest in back, the teeth on the last row as big as the front canines; lower jaw with one small canine on either side of symphysis and 4–5 irregular rows of villiform teeth, the largest in the back; a pair of enlarged canines on each side of the dentary; teeth on the last row as big as the canines; palatine with 4 rows of small villiform teeth; vomer with 5 rows of villiform teeth.

Opercle with 3 spines, the middle one the largest, sharp and pointed, and terminating most posteriorly, the upper one obscured by scales; posterior margin of preopercle with 26 serrae; ventral margin of preopercle smooth and without conspicuous antrorse or retrorse spines; posterior margins of interopercle and subopercle smooth, obscured by scales; posttemporal with 3 small serrations; lower margin of infraorbital 1 smooth; anterior nostril located close to the anterior margin of orbit, with a small flap; posterior nostril located adjacent to anterior border of orbit, without flap.

Scales ctenoid with peripheral cteni; lateral line broadly arched over pectoral fin, following body contour beneath dorsal fin to caudal-fin base; scales between eyes; no scales on maxilla, chin, mandible, lower part of snout, or branchiostegal rays; scales on head starting above the center of the eyes; triangular shaped patch of 6 rows of scales on pectoral fin, extending approximately ¼ – ⅓ length of fin, extending furthest on 7 th and 8 th rays; scales on basal fourth of caudal fin; anal fin with one row of scales along anterior half of base; all other fins without scales.

Coloration when fresh: (Figs 1 A, C View Figure 1 , 2 View Figure 2 ) Body pinkish-white with a series of irregularly shaped patches of red-orange along dorsal two-thirds of body; patches red-orange dorsally and posteriorly, becoming more yellow-orange anteriorly and ventrally; patches are golden yellow on opercle, especially on maxilla; one indistinct yellow stripe crossing opercle diagonally from bottom edge of eye; indistinct orange-red stripe extending from anterior margin of eye to upper lip; orbit white with indistinct yellow stripe through pupil, a continuation of the red-orange stripe originating at the snout tip; sharp break in orange-colored body-patches along lateral line, forming two distinct rows; this is especially pronounced in living specimens; patches above lateral line smaller and associated with pairs or trios of dorsal-fin spines and rays, creating an alternating pattern of five orange spots interspersed with white areas along the base of dorsal fin; patches below the lateral line are larger and more irregular in shape and distribution anteriorly, more rectangular and uniform on posterior half of body; throat and belly white; dorsal fin white at base; interspinous membranes of dorsal fin mostly yellow, white proximally, hyaline distally; membranes of soft dorsal mostly white with yellow stripe roughly midway from body and following contour of body; dorsal spines yellow, rays with yellow tips; anal fin mostly white proximally, yellow distally, with two yellow spots approximately one-third orbit diameter at base of third spine and fifth and sixth soft rays; anal-fin spines white; pelvic fins white proximally, hyaline distally, with yellow-orange spot at base of spine; pectoral fin white to hyaline, with orange spot, approximately one-half diameter of orbit, at fin base; caudal fin white at origin, becoming pale yellow distally, with two irregularly shaped yellow-orange spots, approximately one-third orbit diameter, located on either side of centermost fin rays; additional, smaller spots of similar coloration distally; tips of caudal-fin rays yellow; proximal half of dorsalmost and ventralmost caudal-fin rays yellow-orange.

Color in alcohol: Uniform pale golden-brown with no distinct markings. Scattered melanophores on the nape and along base of dorsal fin (denser on the nape).

Etymology.

The species name, raki , means “ feeling shy to confront people ” in the Dhivehi language. This was chosen because Plectranthias are shy by nature and typically hide from us when we are conducting surveys. To be treated as a noun in apposition.

Distribution and habitat.

Plectranthias raki sp. nov. is known only from the Maldives, where it is likely widespread. It was seen inhabiting small holes of reef walls at several locations between Rasdhoo (4°15'N, 72°57'E) and Dhaalu atolls (2°41'N, 72°51'E) at approximately 100 to 125 m depth.