 |
| [A] Parascolopsis akatamae n. sp. Miyamoto, McMahan & Kaneko, 2020 [B] P. eriomma (Jordan & Richardson, 1909) |
Abstract
A new species of dwarf monocle bream, Parascolopsis akatamae n. sp., is described from the Indo-West Pacific. The new species is distinguished from all other species of Parascolopsis in having 16–19 gill rakers on the first arch, length of forked part of caudal fin 5.8–6.5 times in standard length, eye diameter 1.3–1.8 times in length of the longest dorsal-fin spine, and a pale yellow stripe present from lower edge of the eye to posterior edge of the preopercle. Parascolopsis eriomma (Jordan & Richardson, 1909) is morphologically very similar to the new species and the two have been confused with each other for a long time. Therefore, we redescribe P. eriomma based on the holotype and newly collected specimens. In addition, we found that patterns of biofluorescence emission for both species are clearly different. This suggests that their biofluorescence patterns may function in distinguishing each other.
Keywords: Pisces, Actinopterygii, Taxonomy, biofluorescence
 |
| 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. |
 |
| 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. |
Parascolopsis akatamae n. sp.
[English name: Rosy dwarf monocle bream;
Standard Japanese name: Aka-tamagashira]
Diagnosis. Distinguished from congeners by the following combination of characters: gill rakers on first arch 16–19; caudal fin lightly forked, length of forked part of caudal fin 5.8–6.5 times in SL (Figs. 1A, 2A–D, 3A); eye diameter 1.3–1.8 times in length of longest dorsal-fin spine (Fig. 3B); pale yellow stripe present from lower edge of the eye to posterior edge of the preopercle (Figs. 1A, 2A–D); strong biofluorescence emission observed on isthmus and branchiostegal membrane (Fig. 4A–C) (see paragraph of biofluorescence emission patterns).
Etymology. Parascolopsis akatamae n. sp. has long been confused with P. eriomma. P. akatamae is more widely distributed than P. eriomma (Fig. 5), and more common 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” previously used for P. eriomma more appropriately applies to the new species to avoid unnecessary confusion. The specific epithet “akatamae” is derived from the local name in Japan of the type locality.
Parascolopsis eriomma (Jordan & Richardson, 1909)
[New English name: Swallowtail dwarf monocle bream;
New standard Japanese name: Ennbi-aka-tamagashira]
Etymology. Previously, the English name “Rosy dwarf monocle bream” and Japanese name “Aka-tamagashi-ra” 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.
 |
| 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,D) lateral view, under white light; B,E) lateral view, under blue light; C,F) ventral view, under blue light. |
Kei Miyamoto, Caleb D. McMahan and Atsushi Kaneko. 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); 91–103. DOI: 10.11646/zootaxa.4881.1.6
