Parascolopsis eriomma, : Russell, 1990

Miyamoto, Kei, Mcmahan, Caleb D. & Kaneko, Atsushi, 2020, Parascolopsis akatamae, a new species of dwarf monocle bream (Perciformes Nemipteridae) from the Indo-West Pacific, with redescription of closely related species P. eriomma, Zootaxa 4881 (1), pp. 91-103 : 97-99

Parascolopsis eriomma ( Jordan & Richardson, 1909)

[New English name: Swallowtail dwarf monocle bream; New standard Japanese name: Ennbi-aka-tamagashira] ( Figs. 1 B–C, 2E–F, 3, 4D–F, 5, 6; Table 1 )

Scolopsis eriomma Jordan & Richardson, 1909: 188, Pl. LXX [type locality: Kaohsiung (Takao), Taiwan].

Parascolopsis cf. eriomma: Hung et al. 2016: 11 , fig. S3G (Taiwan).

Parascolopsis eriomma: Fujiwara 2017: 148 , color photograph of UPVMI 1634 (Panay Island, Philippines).

Holotype. FMNH 52247, 190.9 mm SL, Kaohsiung (Takao), Taiwan.

Non-type specimens (14 specimens, 107.9–172.8 mm SL). FMNH 110452, 139.4 mm SL, Dumaguete fish market, Negros Island, Philippines, 21 Sep. 1995, coll. M. W. Westneat ; FMNH 137885, 107.9 mm SL, Puerto Galera fish market, Mindoro Island, Philippines, 24 May 2000, coll. K. Carpenter and M. W. Westneat ; FRLM 34892, 123.9 mm SL, Bitung fish market, north Sulawesi, Indonesia, 14 Nov. 2008, coll. S. Kimura, H. Sakakibara and P. Teguh ; OCF-P 3727, 144.1 mm SL, male, off Motobu , Okinawa-jima Island, southern Japan (26º38′32′′N, 127º45′41′′E), 200 m depth, 28 Sep. 2017, fishing, coll. A. Kaneko, Y. Oshiro and K. Miyamoto ; OCF-P 3802, 139.2 mm SL, female, off Motobu , Okinawa-jima Island, southern Japan (26º39′56′′N, 127º46′38′′E), 150 m depth, 13 Nov. 2017, fishing, coll. A. Kaneko and Y. Oshiro ; OCF-P3888 and 3889, 2 specimens, 123.5 and 172.8 mm SL, male and female, off Motobu , Okinawa-jima Island, southern Japan (26º38′27′′N, 127º45′46′′E), 200 m depth, 14 Feb. 2018, fishing, coll. A. Kaneko, Y. Oshiro and K. Miyamoto ; OCF-P4096 and 4097, 2 specimens, 154.4 and 154.8 mm SL, off Motobu , Okinawa-jima Island, southern Japan (26º38′26′′N, 127º45′39′′E), 200 m depth, 31 May 2019, fishing, coll. A. Kaneko, Y. Oshiro and K. Miyamoto ; OCF-P4209, 4210, 4212 and 4213, 4 specimens, 139.6– 157.2 mm SL, off Motobu , Okinawa-jima Island, southern Japan, 26 Sep. 2019, coll. A. Kaneko and H. Takaoka ; URM-P 37587, 161.2 mm SL, Okinawa-jima Island , 11 Jan. 1997, coll. H. Yoshigo.

Diagnosis. Distinguished from congeners by the following combination of characters: gill rakers on first arch 15–17; caudal fin forked, length of forked part of caudal fin 6.5–7.9 times in SL ( Figs. 1 B–C, 2E–F, 3A); eye diameter 1.1–1.3 times in length of longest dorsal-fin spine ( Fig. 3B ); yellow stripe absent on cheek ( Figs. 1 B–C, 2E–F); very weak or no biofluorescence emission observed on isthmus and branchiostegal membrane ( Fig. 4 D–F) (see paragraph on biofluorescence emission patterns).

Description. Counts and proportional measurements are presented in Table 1 . Body moderately deep, deepest at pelvic-fin base, depth 2.9–3.3 times in SL; head moderate, 3.1–3.3 times in SL; snout short, length less than diameter of eye, 3.8–4.7 times in HL; nostrils small, anterior and posterior nostrils closely aligned, located in front of eye; anterior nostril with small nasal flap; eyes large, round, located in upper portion of anteroposterior axis, diameter 2.4–2.9 times in HL; interorbital width 1.2–1.6 times in eye diameter; suborbital shallow, depth 3.8–5.2 times in eye diameter; mouth moderate, terminal, and slightly oblique; upper jaw nearly reaching to about level of anterior margin of pupil, 2.9–3.3 times in HL; 3–5 pairs of enlarged canines on front of both jaws, single row of small conical teeth follows with canines, villiform teeth present inside canines and small conical teeth; posterior edge of suborbital finely denticulate, with a small spine at upper corner; posterior margin of preopercle finely denticulate; posterior corner of opercle with a small spine.

Origin of dorsal fin above pectoral-fin base, predorsal-fin length 0.9 times in HL; dorsal fin without notch; longest dorsal-fin spine falls within 4th to 6th dorsal-fin spine, longest dorsal-fin spine 2.0–2.2 times in HL; origin of anal fin about level with 1st soft dorsal-fin ray, preanal-fin length 1.5–1.6 in SL; 3rd anal-fin spine longest or almost equal to 2nd anal-fin spine, 3rd anal-fin spine 2.3–2.8 times in HL; posterior tips of dorsal and anal-fin rays falling well short of caudal-fin base; pectoral fins moderately long, tip of fins just reaching level of anus or slightly short, their length 1.1–1.2 times in HL; origin of pelvic fins about level with 3rd dorsal-fin spine, tip of fins just reaching anus or slightly short; length of 1st pelvic-fin ray 1.3–1.5 times in HL; caudal fin forked, tip of upper and lower lobes pointed; length of upper lobe and forked part of caudal fin 3.1–3.6 and 6.5–7.3 times in SL, respectively.

Scales cycloid; scales on top of head extending forward between eyes to about level of posterior margin of pupil; snout, suborbital, lips, maxilla and isthmus naked; preopercle with 3–5 transverse scale rows, its lower limb naked; opercle with 3–6 transverse scale rows; dorsal fin and anal fin scaleless; axilla of pectoral fin naked; pelvic fin with axillary scales; anterior half of caudal fin covered with small scales.

Color of fresh specimens ( Figs. 1B , 2 E–F). Generally reddish body, darker dorsally and paler ventrally; iris red; pale yellow stripe on posterior edge of eye to pectoral-fin base; pale yellow stripe on mid-lateral line of trunk and tail; small black spot on upper portion of pectoral-fin base; dorsal fin mainly red, translucent vermiculate pat-terns present on membrane in small specimens; pectoral, pelvic and anal fins pale yellow; caudal fin mainly red, posterior edge and forked part paler.

Color of preserved specimens. Generally brownish, darker dorsally and paler ventrally; eyes blackish; yellow and red marks present in the fresh condition completely lost with preservation; all fins translucent white.

Biofluorescence emission patterns ( Fig. 4 D–F). Yellow lateral stripe across pupil on iris; weak green stripe on mid-lateral line of trunk and tail; dorsal edge of dorsal fin green; base of pectoral fin green; pelvic and anal fins weakly green; lower lobe and tip of upper lobe of caudal fin green; isthmus and branchiostegal membrane very weak green or without biofluorescence.

Distribution ( Fig. 5 ). Parascolopsis eriomma has been recorded based on specimens or identifiable photographs from southern Japan (this study), Taiwan ( Jordan & Richardson 1909; Hung et al. 2016, this study), Philippines ( Fujiwara 2017; this study) and northern Sulawesi, Indonesia (this study).

Etymology. Previously, the English name “Rosy dwarf monocle bream” and Japanese name “Aka-tamagashira” were used for P. eriomma . However, this study revealed that previously recognized P. eriomma included P. akatamae n. sp. This species is more narrowly distributed than P. akatamae ( Fig. 5 ) and very rare at least in Japan and Taiwan (Hung et al. 2016; this study). Therefore, the English name “Rosy dwarf monocle bream” and Japanese name “Aka-tamagashira,” which were previously used for P. eriomma , were applied to P. akatamae , and a new English name, “Swallowtail dwarf monocle bream” and new standard Japanese name, “Ennbi-aka-tamagashira” have been applied to this P. eriomma . The Japanese “Ennbi” means tail of swallow and is derived from shape of the caudal fin of the species.

Remarks. Scolopsis eriomma Jordan & Richardson, 1909 was originally described on the basis of 3 specimens [FMNH 52247 and CAS-SU 9243 (2 specimens)] collected from Kaohsiung, Taiwan. The original specimen labeled “type” and figured as such (FMNH 52247; Jordan & Richardson 1909) has been considered the holotype ( Henn 1928; Ibarra & Stewart 1987; Ho & Shao 2011). Counts and measurements of examined non-type specimens mostly agree with those of the holotype ( Table 1 , Fig. 3 ). Body depth of the holotype is noticeably higher than non-type specimens, however this is regarded as proportional change with growth because the holotype is the largest among examined specimens. On the other hand, measurements of P. akatamae differ with those of the holotype for diagnostic characters ( Fig. 3 ).

This species was collected from a depth of 150–200 m on a sand-rubble bottom. No sexual dimorphism is observed in morphology, coloration or fluorescence patterns.

Figures

FIGURE 1. Parascolopsis akatamae n. sp. (A) and P. eriomma (B–C). A) fresh specimen, OCF-P4098, holotype, 160.5 mm SL, Okinawa-jima Island, Japan; B) fresh specimen, OCF-P4097, 154.4 mm SL, Okinawa-jima Island, Japan; C) preserved specimen, FMNH 52247, holotype, 190.9 mm SL, Kaohsiung, Taiwan.

FIGURE 2. Fresh specimens of Parascolopsis akatamae n. sp. (A–D) and P. eriomma (E–F) at different growth stages. A) OCF-P4119, 98.3 mm SL, Okinawa-jima Island, Japan; B) OCF-P4071, 140.1 mm SL, Okinawa-jima Island, Japan; C) OCF- P4123, 179.7 mm SL, Okinawa-jima Island, Japan; D) OCF-P4089, 252.7 mm SL, Ishigaki-jima Island, Japan; E) OCF-P4212, 139.6 mm SL, Okinawa-jima Island, Japan; F) OCF-P3889, 172.8 mm SL, Okinawa-jima Island, Japan.

FIGURE 3. Relationships of length of forked part of caudal fin to standard length (A) and length of longest dorsal-fin spine to eye diameter (B) in Parascolopsis akatamae n. sp. (blue markers) and P. eriomma (red markers). Large squares indicates data from holotypes. Regression equations for (A) P. akatamae: y = 0.1473x + 2.4922, R2 = 0.9729; P. eriomma: y = 0.104x + 5.7483, R2 = 0.9234, and (B), P. akatamae: y = 1.7484x - 4.865, R2 = 0.8817; P. eriomma: y = 1.5366x + 5.3993, R2 = 0.8184.

FIGURE 4. Biofluorescence emission patterns of Parascolopsis akatamae n. sp. (A–C, OCF-P4098, holotype, 160.5 mm SL) and P. eriomma (D–F, OCF-P4097, 154.4 mm SL).A) lateral view, under white light; B) lateral view, under blue light; C) ventral view, under blue light; D) lateral view, under white light; E) lateral view, under blue light; F) ventral view, under blue light.

FIGURE 5. Distribution of Parascolopsis akatamae n. sp. and P. eriomma. Closed markers are based on specimens examined during this study; open markers are based on literature records (identified from color photographs).