Festucalex rosa, Yuki & Motomura, 2025

Festucalex rosa sp. nov.

[New English name: Pink-rose Pipefish]

Fig. 1 View FIGURE 1

Festucalex erythraeus View in CoL (non Gilbert, 1905). Moots 2022 [center right photo on pl. 83 ( Seychelles), identified by Moots (2022)

as F. erythraeus View in CoL ; Note: description of F. erythraeus View in CoL by Moots (2022: 453) based on valid specimens of F. erythraeus View in CoL ].? Festucalex sp. : Moots 2022: 454 (Kosi Bay, KwaZulu-Natal, South Africa).

Holotype. BPBM 35535, 77.8 mm SL, male, north of D'Arros Island , Amirantes, Seychelles, 05°24′S, 53°19′E, 45–55 m depth, 26 Dec. 1992, dredge, J. van der Land et al., RV Tyro, St. 752. GoogleMaps

Diagnosis. A new species of Festucalex with the following combination of characters: 17 trunk rings; 34 tail rings; 21 dorsal-fin rays; 14 or 15 pectoral-fin rays; snout length 46.3% of head length; lateral trunk ridge ending at anal ring; pectoral-fin base with two ridges.

Description. Dorsal-fin rays 21; anal-fin rays 4; pectoral-fin rays 14 or 15; caudal-fin rays 10; subdorsal rings 4.5; trunk rings 17; tail rings 34; total rings 51. Proportional measurements as percentage of SL: HL 11.1; pre-dorsal-fin length 40.1; trunk length 29.5; tail length 59.3; SnL 5.1; snout depth 1.5; anal ring depth 3.8; body width 3.8; dorsal-fin base length 7.4; pectoral-fin length 1.9; pectoral-fin base length 1.5; caudal-fin length 2.7. Proportional measurements as percentage of HL: dorsal-fin base length 67.1; pectoral-fin length 13.2; SnL 46.3; orbit diameter 17.8; postorbital length 37.7; interorbital width 16.3; head width 35.6. Proportional measurements as percentage of SnL: snout depth 29.0.

Body elongated, slightly compressed; trunk shorter than tail; first trunk ring longer than second; superior ridges entire; superior trunk ridges indented between rings, usually elevated above level of dorsum; posterior angles of tail rings not produced; dermal flaps and keeled scutella absent, principal body ridges distinct, entire, not angled laterally or produced as hook-like points; ventrum of trunk V-shaped, without median longitudinal keel; superior and inferior trunk ridges continuous with respective tail ridges; lateral trunk ridge not straight, ending on anal ring; snout slender; principal ridges of posteriormost 1 and 2 tail rings without knobs or spine-like projections; median dorsal snout ridge low, with two peaks and broken between peaks, thin, not strongly elevated, produced upward from near middle of snout; lateral snout ridge low; supraopercular ridge low; orbital ridge somewhat elevated dorsally; supraoccipital and anterior nuchal plates low, distinct; posterior nuchal plate low, short, indistinct; opercular ridge low, indistinct, restricted to anterior quarter of opercle, remainder of opercle finely sculptured by radiating striae. Jaws without odontoid processes; nares minute, 2-pored bilaterally. Dorsal-fin base not raised; posterior margin of pectoral fin rounded; anal fin very small; caudal fin rounded, membranes between each soft ray with slit. Head and body without dermal flaps. Brood pouch on ventral surface from first to 14th tail rings; pouch protective plates little enlarged.

Color of fresh specimen ( Fig. 1A View FIGURE 1 ). Ground color of body pink; snout pale whitish, head (excluding snout) pink. Head and body with white dots; postorbital, body and caudal-fin base with 13 diffuse white bars. Anterior margin of opercle with a yellow line. Margins of superior, lateral, and inferior trunk ridges dark pink. Dorsal fin transparent. Caudal fin uniformly pink, with white spots.

Color of preserved specimen ( Fig. 1B View FIGURE 1 ). Head and body yellow. Sides and ventrum of trunk with scattered melanophores. Brood pouch yellowish-white. Dorsal, pectoral, anal, and caudal fins translucent.

Distribution. Currently known only from D'Arros Atoll, Seychelles; possibly also from Kosi Bay, KwaZulu-Natal, South Africa (see synonym list and Remarks). A possible record from Kosi Bay, South Africa ( Moots 2022), if confirmed, would represent a considerable range extension for the species.

Etymology. The specific name ‘‘ rosa ,’’ treated as a noun in apposition, is derived from Latin meaning “rose”, in reference to the body color of the new species.

Remarks. The new species conforms to the diagnostic characters of the genus Festucalex (see above), in which it is similar to F. armillatus , F. gibbsi , F. prolixus and F. wassi in possessing two ridges on the pectoral-fin base, but differs by exhibiting 17 trunk rings ( 18 in F. gibbsi , 14 or 15 in F. wassi ), 34 tail rings (31 or 32 in F. armillatus , 32 or 33 in F. gibbsi and F. wassi ), 14 or 15 pectoral fin rays (12 or 13 in F. armillatus , 16 or 17 in F. wassi ), the snout length 46.3% HL (40.0–41.7% in F. armillatus , 55.6–60.6% in F. wassi ), and lateral trunk ridge ending at the anal ring (3rd or 4th tail ring in F. armillatus , 1st–3rd tail ring in F. gibbsi , 10th–13th tail ring in F. prolixus , 2nd tail ring in F. wassi ) ( Dawson 1977, 1984, 1985; Prokofiev 2016; Yuki et al. 2024a, b, 2025). In addition, the new species is similar to F. erythraeus in having 17 trunk rings ( 15–17 in F. erythraeus ), 34 tail rings (32–37), 21 dorsal-fin rays (18–21), 4.5 subdorsal rings (4.25–5.75), 46.3% HL (38.5–47.6%), and the snout depth 29.0% SnL (25.6–40.0%), but can be distinguished from the latter by having two ridges on the pectoral-fin base (0 or 1 ridge in F. erythraeus ), 14 or 15 pectoral-fin rays (10–13), and the head length 11.1% SL (11.4–12.5%) ( Dawson 1977, 1985; Moots 2022; this study).

Festucalex sp. , reported by Moots (2022: 454) based on a single female specimen ( 60.7 mm SL) from South Africa, is most likely conspecific with F. rosa , judging from the description given for the specimen, including 51 total rings, 21 dorsal-fin rays, 14 pectoral-fin rays, snout length 45.5% of HL, lateral trunk ridge ending on anal ring, and two ridges on the pectoral-fin base. However, F. rosa is different from Moots’ Festucalex sp. in having 17 trunk rings ( 16 in Festucalex sp. ), ridges on the posteriormost 1 and 2 tail rings without knobs or spine-like projections (with microserrates), and the opercular ridge restricted to anterior one-fourth of the opercle (extending onto anterior half of opercle). Additional specimens of the new species are required in order to assess the taxonomic status of Moots’ Festucalex sp. In addition, the photographed specimen reported by Moots (2022: pl. 83) as F. erythraeus is here established as the holotype of F. rosa . However, the description of F. erythraeus given by Moots (2022: 453) clearly differed from that of F. rosa given here [18–20 dorsal-fin rays (vs. 21 in F. rosa ), 10–12 pectoral-fin rays (vs. 14 or 15), and lacking prominent ridges on the pectoral-fin base (vs. two ridges present)], and was clearly based on correctly identified examples of the former.