Research Article |
Corresponding author: Tzu-Yung Lin ( plextorx0428@nkust.edu.tw ) Academic editor: Nina Bogutskaya
© 2023 Hsuan-Ching Ho, Yo Su, Nok-Sum Leung, Tzu-Yung Lin.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ho H-C, Su Y, Leung N-S, Lin T-Y (2023) New records of a rare gibberfish, Gibberichthys latifrons (Stephanoberyciformes, Gibberichthyidae), from the South China Sea, with comments on morphological characters. ZooKeys 1172: 47-59. https://doi.org/10.3897/zookeys.1172.102433
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The gibberfish Gibberichthys latifrons is recorded for the first time from southwestern Taiwan, northern South China Sea, based on the collection of seven adults and subadults from the Dong-gang fish market, Pingtung. These specimens represent the northernmost extent of the adult range of the species, and they fill a distributional gap in the western Pacific Ocean. Our findings suggest that a population of the species has become recently established in the region. Detailed descriptions, otolith morphology, and fresh coloration are provided with comments on the morphological characteristics of the genus.
Biodiversity, biogeography, ichthyology, otolith, Small-scaled gibberfish, taxonomy
Members of the fish family Gibberichthyidae are known for a long leaf-like pelvic appendage in larvae and juveniles, the so-called kasidoron stage, and the appendage is lost at approximately 21–31 mm standard length (
During 2021–2023, we collected seven adults (with developed gonads) and subadults (sex indeterminate) from bycatches of deep bottom trawls that were landed in the Dong-gang fish market in southwestern Taiwan. Detailed descriptions, full morphological data, otolith morphology, and photographs are provided for the first time. These specimens represent a new record for the family, genus, and species in Taiwan. They are also the northernmost collection of adults of the species and the third record in the northern hemisphere. We also discuss the morphological characters of G. latifrons and compare them to those of G. pumilus based on the previous literature and our new specimens.
Methods for taking measurements generally follow
Gibberichthys
Parr, 1933: 5 (type species: Gibberichthys pumilus Parr, 1933; by monotypy);
Kasidoron Robins & de Sylva, 1965: 190 (type species: Kasidoron edom Robins & de Sylva, 1965 [synonym of G. pumilus], by original designation and monotypy).
Body moderately long, body depth 3–4 times in SL; head large, its length c. 2.5 in SL, fine spiny ridges on head associated with skull ridges; dorsal and anal fins with anterior spines firmly attached to supporting bones; soft-ray portions of dorsal and anal fins distinctly taller than spinous portions; thin tube-like lateral-line canal with c. 32–36 vertical bars, each bearing 6–8 papillae; scales deciduous, covered by skin; pectoral fin small, its base low in position; pelvic fin small, its origin behind pectoral-fin base; anus situated at mid-point of pelvic fins, well in front of anal-fin origin; caudal fin small, forked; total dorsal-fin elements 14–17, anal-fin elements 11–14; total gill rakers 18–23; pyloric caeca 9–13; total vertebrae 28–32. Coloration dark red to black.
Kasidoron latifrons Thorp, 1969: 63, figs 1–4 (type locality: Western Indian Ocean off Zanzibar, Tanzania, 8°34'S, 42°37'E, from stomach content of lancetfish).
Gibberichthys latifrons
(Thorp, 1969):
Tables
Dorsal-fin elements 5–7 (fixed spines) + 1–2 (movable spines) + 8–9 (soft rays), all rays branched (1 specimen with first ray simple). Pectoral-fin elements 13–14 (1 with 15 in one side), upper and lowermost rays unbranched, others branched. Pelvic-fin elements I, 4–6, spine short and movable, slightly recurved, all rays branched. Anal-fin elements 2–4 (fixed spines) + 1–2 (movable spines) + 7–8 (soft rays). Principal caudal-fin rays 10 + 9, uppermost and lowermost rays unbranched; procurrent caudal-fin rays 7–8 and 6 on upper and lower lobes, respectively. Gill rakers on 1st arch 5–6 + 13–15 = 18–21; on 2nd arch 4–5 + 12–13 = 16–18; on 3rd arch 2 + 10–11 = 12–13; and on 4th arch 0 + 6–8 = 6–8. Lateral line with c. 32–36 vertical branches (some damaged); scale rows along lateral line c. 40–44 (many lost); scale rows above lateral line 5–7; scale rows below lateral line c. 18–21. No abdominal scutes. Pyloric caeca 9–13 (n = 4). Vertebrae 12–13 + 18–20 = 30–32 total (n = 7); branchiostegal rays 9; interneural 3, upper ends slightly extended upwards on dorsum forming three bumps.
Body moderately long, rather thick, depth at dorsal-fin origin 2.9–3.7 in SL. Head large, length 2.3–2.7 in SL, its height clearly less than its length, 1.3–1.5 in HL; upper profile of head convex, gently curved to dorsal-fin origin; forehead convex and broad, HF1 8.1–10.2 and HF2 4.3–4.6 in HL; eyes small, width 3.7–5.5 in HL; snout convex and short, not extending before premaxilla, length 2.5–3.2 in HL; interorbital space broad, width 2.0–2.5 in HL; postorbital length 1.9–2.1 in HL.
Mouth large, upper-jaw length 1.6–1.7 in HL; posterior end of maxilla rounded, slightly beyond vertical through posterior margin of eye; lower-jaw length slightly larger than upper-jaw length, 1.5–1.6 in HL. Upper jaw overhanging lower jaw completely. Two nostrils at same horizontal level, anterior nostril at about middle of snout; posterior nostril oval, much larger than anterior nostril, right in front of eye. Symphysis of premaxillae forming deep notch, edentate. Symphysis of dentaries with small blunt knob and edentate. Supramaxilla single, with long needle-like process extending anteriorly and long rectangular process posteriorly; covering about third of posterior portion of maxilla in width.
Spiny ridges associated with skull ridge present on head (including snout, jaws, cheek, chin, and gill cover), nape, and pectoral girdle. A small rounded fenestration on each side of supraorbital region, usually covered by skin and can only be observed when skin removed. Outer premaxillary surface completely exposed, extending almost to posterior end of maxilla and bearing villiform teeth along entire length, except for largely naked on middle areas of anterior half, followed by narrow tooth band on posterior half of the bone. Dentary completely covered by upper jaw when mouth closed; a narrow band of villiform teeth extending over about 3/4 of upper jaw. Palatine and vomer toothless.
Gill rakers rod-shaped with pointed tip, somewhat laterally compressed, covered with small teeth on inner surfaces; rakers in outer row of first arch longer than remainder, longest gill raker about equal in length to eye diameter; no raker on inner surface of first arch; gill rakers in outer row of second arch slightly shorter than those in outer row of first arch; gill rakers in outer row of third arch shorter than those in two anterior arches; low knobs present in inner rows of second and third arches; single row of short, somewhat knob-like rakers on fourth arch. Tooth patch present on fifth ceratobranchial. Long, oval tooth patch on third epibranchial arch. Large, triangular villiform tooth patch on second pharyngeal arch and small irregularly triangular tooth patch on third pharyngeal arch. Gill filaments on first arch short, about half length of longest opposite rakers.
Body covered with cycloid scales, all embedded under thin skin. Head entirely naked. Lateral-line scales not distinct from neighboring scales.
Dorsal fin low, with long base, length of dorsal-fin base 3.2–3.7 in SL. Pectoral fin short, its length 2.3–2.5 in HL, tip slightly pointed, reaching to or slightly beyond vertical through anal-fin origin. Pelvic fin short, its length 3.5–4.1 in HL, tip reaching anal-fin origin. Anal fin moderately small, its base length 1.7–2.0 in HL. Caudal fin moderately large, forked, its length 2.2–2.7 in HL.
Lateral line single, originating behind posttemporal bone; its anterior portion slightly curving down, running along dorsal profile on about upper fifth of body, with nearly straight posterior portion ending at caudal-fin base. Clear but weak lateral-line canal along surface of body, with about 32–36 pairs of pale upper and lower vertical extensions, each bearing about 3 papillae (partly damaged by trawl operation in examined specimens).
Anus situated anteriorly, between middle of pelvic fins, clearly anterior to anal-fin origin. Light organ absent. Caudal peduncle long, rather thick, its length 1.4–1.7 in HL, height 3.3–6.1 in HL.
Sagittal otoliths were taken from NMMB-P37470, 101.0 mm SL (right: 1.92 mm in length x 2.17 mm in width, left: 2.03 x 2.20) and 97.2 mm SL (right: 2.01 x 2.26, left: 2.12 x 2.28) (Fig.
When fresh, body dark brown to black mixed with deep red color. Mouth cavity and gill chamber orange-red. When preserved, body uniformly black with pale mouth cavity and gill chamber. Stomach and pyloric caeca white, intestine orange-red on anterior half, paler on posterior half. Peritoneal membranes light orange-red on pale gray background. Mouth cavity and gill chamber orange-red on bluish gray background.
The largest specimen (103.0 mm SL) is a mature female with two large ovaries containing many large, loose eggs (c. 0.6–0.7 mm). Three other specimens (97.2, 101.0 and 100.7 mm SL) are mature males with well-developed testis.
Originally described from the western Indian Ocean (
Table
Morphometric data of Gibberichthys latifrons. Abbreviations: A, anal-fin; D, dorsal-fin; PO, pectoral-fin origin; VO, pelvic-fin origin. Data sources: 1. This study, 2.
Gibberichthys latifrons | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Data sources | 1 | 2 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 4 |
SL (mm) | 49.6 | 64.0 | 77.6 | 82.2 | 86.0 | 97.2 | 100.7 | 101.0 | 103.0 | 134.0 |
% SL | ||||||||||
HL | 42.8 | 40.6 | 42.8 | 39.3 | 41.9 | 36.5 | 39.7 | 38.7 | 38.4 | 38.9 |
Head depth | 33.4 | 31.3 | 31.0 | 31.2 | 28.5 | 23.9 | 26.3 | 25.5 | 26.4 | 24.7 |
Snout length | 13.4 | 15.6 | 14.2 | 14.0 | 15.7 | 14.8 | 14.1 | 15.2 | 14.6 | 12.7 |
Eye diameter | 11.7 | 7.8 | 8.3 | 8.5 | 7.2 | 6.8 | 7.3 | 7.0 | 7.1 | 5.2 |
Interorbital width | 21.4 | 18.8 | 19.0 | 17.6 | 18.0 | 16.3 | 15.9 | 17 | 16.5 | 14.7 |
Forehead 1 | 4.6 | 2.3 | 4.2 | 4.6 | 5.2 | 3.9 | 3.7 | 4.6 | 4.8 | 3.5 |
Forehead 2 | 9.9 | – | 9.7 | 9.4 | – | 8 | 8.8 | 8.9 | 8.8 | – |
Postorbital length | 22.2 | 20.3 | 22.1 | 19.5 | 19.2 | 17.8 | 19.3 | 19.2 | 19.7 | 20.2 |
Upper-jaw length | 27.1 | 24.2 | 25.9 | 25.1 | 26.2 | 22.4 | 23.5 | 23.7 | 22.4 | 20.4 |
Lower-jaw length | 28.8 | 26.6 | 28.2 | 27.1 | 27.3 | 24.2 | 24.6 | 25.0 | 24.5 | 18.0 |
Body depth | 30.2 | 29.7 | 34.8 | 31.5 | 30.2 | 27.1 | 28.5 | 28.5 | 31.7 | 25.8 |
Caudal-peduncle length | 24.8 | 26.6 | 25.9 | 23.6 | 25.0 | 27.0 | 27.1 | 23.9 | 24.3 | 15.3 |
Caudal-peduncle depth | 7.1 | 8.6 | 10.2 | 7.6 | 9.3 | 10.9 | 8.5 | 11.4 | 10.1 | 9.3 |
Predorsal length | 44.3 | 46.9 | 48.1 | 47.2 | 49.1 | 46.0 | 46.0 | 44.5 | 50.1 | 44.3 |
Preanal length | 57.1 | 54.7 | 56.4 | 60.2 | 62.3 | 57.6 | 56.4 | 57.6 | 58.5 | 48.0 |
Prepectoral length | 46.8 | 43 | 44.3 | 43.4 | 51.2 | 41.0 | 40.1 | 40.7 | 41.4 | 38.9 |
Prepelvic length | 48.5 | 36.9 | 48.0 | 49.7 | 54.1 | 47.0 | 47.2 | 47.6 | 50.0 | 43.2 |
PO–VO | 8.4 | 4.7 | 7.5 | 8.2 | 7.0 | 8.8 | 10.5 | 8.8 | 11.5 | 4.8 |
Longest D ray | – | – | – | – | – | 12.3 | 14.0 | 13 | 11.9 | – |
Dorsal-fin base | 29.6 | 28.1 | 30.9 | 29.4 | 22.1 | 29.4 | 27.2 | 31 | 28.2 | 29.5 |
Longest A ray | 15.0 | – | – | – | – | 12.8 | 12.1 | 12.7 | 11.7 | – |
Anal-fin base | 23.2 | 21.9 | 21.1 | 22.1 | 18.6 | 20.9 | 20.7 | 21.2 | 20.7 | 22.2 |
Pectoral-fin length | 18.2 | 21.1 | 16.3 | 16.4 | 19.8 | 14.7 | 16.9 | 16.9 | 15.9 | 16.4 |
Pelvic-fin length | – | 10.2 | 10.8 | 8.1 | 11.6 | 10.0 | 11.3 | 9.7 | 9.3 | 11.7 |
Caudal-fin length | – | – | – | – | – | 15.9 | 17.3 | 17.6 | 14.4 | – |
There are three interneurals that extend dorsally and form lumps on the midline behind the head in our specimens, but these interneurals are less prominent than those in pre-juveniles observed by
The six larger specimens examined in this study have a normal pelvic fin with the 3rd ray not especially thickened; they do not have a “discontinuity area” as shown by
Table
Meristic data of two Gibberichthys species. Data source: 1. This study, 2.
G. latifrons | G. pumilus | ||||||
---|---|---|---|---|---|---|---|
n = 7 | n = 3 | n = 1 | n = 1 | Larva (n = 1) | Juvenile (n = 1) | – | |
Data sources | 1 | 2 | 3 | 4 | 5 | 5 | 2 |
Dorsal-fin elements | VII–IX, 7–8 | V–VIII, 8–9 | VIII, 8 | VII, 8 | 12 | c. VI, 8 | V–VII, 8–9 |
Pectoral-fin elements | 13–14/13–15 | 12–15 | 14 | – | 13/13 | 14/14 | 13–15 |
Pelvic-fin elements | I, 4–6 | I, 5–6 | I, 5 | 5 | 6/6 | I, 5/I, 5 | I, 5–6 |
Anal-fin elements | IV–V, 7–8 | IV–V, 7–9 | V, 7 | IV, 7 | 13 | V, 7 | IV–V, 7–9 |
Caudal-fin elements | 7–8 + 10 + 9 + 6 | – | – | 7 + 10 + 9 + 7 | 7 + 10 + 9 + 5 | 7 + 10 + 9 + 6 | – |
Gill rakers on 1st arch | 5–6 + 13–15 = 18–21 | 5–7 + 13–16 = 18–23 | 6–7 + 14 = 20–21 | 5 + 13 = 18 | 21/22 | 18/17 | 5–6 + 14–16 = 18–22 |
Gill rakers on 2nd arch | 4–5 + 12–13 = 16–18 | – | – | – | – | – | – |
Gill rakers on 3rd arch | 2 + 10–11 = 12–13 | – | – | – | – | – | – |
Gill rakers on 4th arch | 0 + 6–8 = 6–8 | – | – | – | – | – | – |
Pseudobranchial filaments | 9–11 | – | – | – | – | – | – |
Lateral-line branches | c. 32–36 | 33–36 | – | – | – | – | 28–32 |
Lateral-line scales | 40–44 | – | – | – | – | – | – |
Scale rows above lateral line | c. 5–7 | 7–8 | – | – | – | – | 4 |
Scale rows below lateral line | c. 15–21 | 15–16 | – | – | – | – | 7 |
Pyloric caeca | 9–13 | 11 | – | – | – | – | 12–13 |
Vertebrae | 12–13 + 18–20 = 30–32 | 12 + 20 = 32 | 14 + 17 = 31 | 31 | – | – | 28–29 |
There are nine to 13 (n = 4) pyloric caeca in our specimens, whereas G. pumilus has 12 or 13 (
We counted 14 (n = 1), 15 (n = 3), or 16 (n = 3) total dorsal-fin elements for our specimens.
Our specimens have 13–14 pectoral-fin rays (one with 15 in one side), 10 + 9 principal rays, and 7–8 (upper)/6 (lower) procurrent rays on the caudal fin, identical to that reported in the literature. We counted 30 (n = 3), 31 (n=2) and 32 (n = 2) vertebrae in our specimens, which agree with those provided in the literature.
Although some of the body scales may have been lost due to the trawling operation, many scales remained in our specimens. The scales are cycloid, generally higher than wide, densely overlapping, and covered by thin epidermis all over the entire body, including fin bases. Those associated with the lateral line are about the same size and form as neighboring scales and not especially enlarged; no pored scales were detected. It is notable that
Based on our examination, there is a thin but clear tube-like canal on the body epidermis that forms the lateral line, plus approximately 32–36 pairs of pale vertical bars, evenly distributed along the upper and lower portion of the lateral-line canal. Each vertical bar bears three black papillae.
Because our specimens have some damaged skin on the head, it is difficult to observe the exact number of head pores. However, the arrangement of pores is similar to that described in the literature. It is notable that one of our specimens has most of the head skin lost and has white neuromasts along the canal that appear to be associated with head pores.
By consolidating information from the literature with data from our newly collected specimens, we can now confidently distinguish adults and subadults of G. latifrons from its only congener G. pumilus by the following suite of characters: G. latifrons has considerably larger body scales (estimated about twice the size of those in G. pumilus), slightly more (14–17) total dorsal-fin elements (vs. 13–15), and 30–32 total vertebrae (vs. 28–29). Our findings begin to fill the gaps in the distribution in the western Pacific Ocean and adult morphology of G. latifrons. We also document ontogenetic changes in certain morphometric characters. And we suggest a recent northward distributional expansion into the norther hemisphere waters of southern Taiwan.
We thank K.-H. Wu and Y.-M. Huang for assistance in sampling collections; C.-H. Lin and H.-W. Liu (Academia Sinica, Taiwan) for help on the otolith registration and photographs; H.-C. Lin (NSYSU) for providing facilities; and T.-Y. Liao (
The authors have declared that no competing interests exist.
No ethical statement was reported.
This study is supported by the National Museum of Marine Biology & Aquarium, Pingtung, Taiwan, and the National Kaohsiung University of Science Technology, Kaohsiung, Taiwan.
Conceptualization: HCH. Funding acquisition: TYL. Resources: NSL. Writing – original draft: HCH. Writing – review and editing: YS.
Hsuan-Ching Ho https://orcid.org/0000-0003-1154-601X
Yo Su https://orcid.org/0000-0002-3576-9229
Nok-Sum Leung https://orcid.org/0009-0007-3313-3263
Tzu-Yung Lin https://orcid.org/0000-0002-9034-4397
All of the data that support the findings of this study are available in the main text.