Stolephorus waitei

Hata, Harutaka, Wibowo, Kunto, Lavoué, Sébastien, Pogonoski, John J., Appleyard, Sharon A. & Motomura, Hiroyuki, 2024, Enhanced data on Stolephorus grandis and Stolephorus waitei (Teleostei: Clupeiformes: Engraulidae), two species endemic to the Sahul Shelf, western Pacific Ocean, Zootaxa 5538 (1), pp. 1-22 : 13-19

Stolephorus waitei Jordan & Seale, 1926

[English name: Waite’s Anchovy]

Figure 5 ; Tables 1 , 2

Stolephorus waitei Jordan & Seale, 1926: 379 (type locality: Queensland, Australia); Whitehead et al. 1988: 419, unnumbered fig. (in part: Queensland, Australia); Wongratana et al. 1999: 1742, unnumbered fig. (in part: Queensland, Australia); Paxton et al. 2006: 315 (Queensland, Australia); Hata et al. 2019: 37, fig. 20 (south of Cooktown, Queensland, Australia; Queensland, Australia).

Anchoviella waitei : Fowler 1941: 702 (Queensland, Australia).

Stolephorus Species A : Whitehead et al. 1988: 420, unnumbered fig. (south of Cooktown, Queensland, Australia).

Materials examined. 23 specimens, 63.2–129.6 mm SL, all specimens collected from Australia.

Holotype. MCZ 18254 , holotype of Stolephorus waitei , 87.6 mm SL, Queensland.

Nontype specimens. AMS I. 20907-026 , 3 specimens, 77.3–85.7 mm SL , AMNH 56134 , 3 specimens, 81.6– 94.6 mm SL, south of Cooktown , Queensland (16°01′S, 145°29′E), 0–20 m depth, trawl ; ANSP 122439, 101.7 mm SL, Townsville , Queensland ; CSIRO H 6715-03 (tissue code: BW-A17752; BOLD accession number: FOAQ1054- 24 ), 105.0 mm SL, approx. 11 km east of Keppel Sands , Queensland (23°20′S, 150°54′E), 13 m depth ; CSIRO H 7023-05 , 63.2 mm SL, north of Hinchinbrook Island , Queensland (18°12′S, 146°16′E), 8 m depth ; CSIRO H 8762- 32 (BW-A16633, FOAQ666-21), 74.9 mm SL, Gulf of Carpentaria, south of Groote Eylandt , Northern Territory (14°28′S, 136°38′E), 29 m depth ; CSIRO H 8965-01 (BW-A17753; FOAQ1053 -24), 110.0 mm SL, approx. 18 km northwest of Marrett River , Queensland (14°16′S, 144°03′E), 15 m depth ; NTM S.11898-014 , 4 of 14 specimens, 99.6–108.7 mm SL, approx. 85 km north of Marchinbar Island (10°18′S, 136°30′E) ; NTM S.12935-014 , 122.6 mm SL, north of Croker Island , Northern Territory (10°44′20.4″S 132°31′48.0″E) ; NTM S.12989-004 , 6 specimens, 117.1–129.6 mm SL, North of Cape Don , Northern Territory (11°04′01.2″S, 131°40′01.2″E) .

Materials for distributional records (morphometric and meristic data not collected; COI sequence of one specimen determined; 23 specimens: 43–125 mm SL). CSIRO A 2866, 93 mm SL , CSIRO A 2867, 87 mm SL , CSIRO A 2868, 88 mm SL , CSIRO A 2869, 99 mm SL, south of Mornington Island, Gulf of Carpentaria , Queensland, Australia (17°27′42.0″S, 139°56′48.0″E), 7 m depth ; CSIRO A 2899 , 82 mm SL, Gulf of Carpentaria , Queensland, Australia (17°30.6′S, 140°32.6′E), 4 m depth ; CSIRO A 3046, 100 mm SL, Kerema Bay, Gulf of Papua , Papua New Guinea (07°57′S, 145°46′E) ; CSIRO B 354, 43 mm SL, mouth of Norman River, Gulf of Carpentaria , Queensland, Australia (17°27′S, 140°50′E) ; CSIRO C 3714, 123 mm SL, northeast of Gove , Northern Territory, Australia (12°00′S, 137°30′E), 55 m depth ; CSIRO CA 2310, 125 mm SL; CSIRO CA 2311, 127 mm SL, northeast of Cape Talbot , Western Australia, Australia (13°16′S, 127°05′E), 90–95 m depth ; CSIRO H 3630-01 , 84 mm SL ; CSIRO H 3630-02 , 3 specimens: 60–83 mm SL, west-northwest of Weipa, Gulf of Carpentaria , Queensland, Australia (12°29′06″S, 141°31′36″E), 18 m depth ; CSIRO H 6548-10 , 72.7 mm SL, north of Bundaberg , Queensland, Australia (24°26′17.4″S, 152°04′30.0″E), 14 m depth ; CSIRO H 6715-04 , 3 specimens, 97–122 mm SL, Keppel Bay , Queensland, Australia (23°19′30.6″S, 150°54′58.8″E), 13 m depth ; CSIRO H 6933-08 , 110.0 mm SL, Keppel Bay , Queensland, Australia (23°20′19.2″S, 150°51′47.4″E), 9 m depth ; CSIRO H 7023-06 , 3 specimens, 60–68 mm SL, north of Hinchinbrook Island , Queensland, Australia (18°12′20.4″S, 146°15′59.4″E), 8 m depth ; CSIRO H 8850-01 (BW-A16960, FOAQ796-22), 58 mm SL, off Cape Blackwood, Gulf of Papua , Papua New Guinea (08°00.78′S, 144°41.48′E), 19–21 m depth .

Diagnosis. A species of Stolephorus with the following combination of characters: 1UGR 17–19 (modally 18), 1LGR 23–26 (24), 1TGR 41–44 (42); 2UGR 11–13 (13), 2LGR 21–23 (22), 2TGR 32–35 (35); 3UGR 9–12 (11), 3LGR 11–13 (12), 3TGR 21–25 (23); 4UGR 8–11 (9), 4LGR 9–11 (11), 4TGR 17–22 (20); prepelvic scutes 4–6 (6); scale rows in longitudinal series 36–41 (41); transverse scales 8; pseudobranchial filaments 24–36 (28); vertebrae 41; paired dark patches on parietal and occipital regions; no double lines on dorsum; a few black spots on suborbital area and tip of lower jaw; predorsal scute absent; no spine on pelvic scute; posterior margin of preopercle rounded, not indented; maxilla comparatively short, 17.9–20.4% of SL (mean 19.2%), its posterior tip not reaching to posterior margin of preopercle; lower jaw comparatively short, 15.1–17.5% of SL (16.6%); short anal-fin base 12.9–16.9% of SL (14.9%); long caudal peduncle, 20.3–23.4% of SL (21.8%).

Description. Body elongated, subcylindrical, deepest at dorsal-fin origin. Dorsal profile gently elevated from snout tip to dorsal-fin origin, thereafter, gradually descending to dorsal contour of central part of caudal peduncle. Ventral profile gently descending from tip of lower jaw to insertion of pelvic fin, thereafter nearly straight (parallel to body axis) to origin of anal fin, subsequently ascending along anal-fin base. Ventral contour of caudal peduncle nearly straight and parallel to body axis. Abdomen rounded, covered with four to six prepelvic scutes. Prepelvic scutes spine-like, retrorse, hard. No scutes on abdomen posterior to pelvic scute. No spine on pelvic scute. Predorsal scute absent. Snout projecting, rounded, positioned lower than upper margin of eye. Orbit elliptical, entirely covered with eyelid. Eye longer than snout, positioned above pectoral-fin insertion. Iris round. Interorbital space flat, narrower than eye diameter. Nostrils positioned close to each other, just anterior to orbit. Mouth large, inferior, almost parallel to body axis, extending to posterior margin of orbit. Maxilla rather short, not reaching to posterior margin of preopercle. Lower jaw slender. Mandibular joint located posterior to posterior margin of eye. Uniserial small conical teeth on both jaws. Several rows of conical teeth on palatines. Several conical teeth present on vomer. Teeth patch formed by fine, densely packed teeth present on pterygoids. Several rows of conical teeth on upper edges of basihyal. Dorsal surface of hyoid arch entirely smooth. Posterior margins of preopercle, subopercle, and opercle rounded (not indented), smooth, without serrations. Pseudobranchial filaments present on inner side of opercle and exposed, not covered with skin (visible without dissection); length of longest filament less than eye diameter. Gill arch four pairs, gill rakers present on anterior surfaces of all gill arches and posterior surface of third gill arch. Gill rakers slender, rough, visible from side of head when mouth opened. Gill filaments present on all gill arches. Isthmus muscle long, anteriorly reaching to posterior margin of gill membranes. Urohyal embedded in isthmus muscle, not visible without dissection. Gill membranes on both sides joined distally, most of isthmus muscle exposed (not covered by gill membrane). Branchiostegal rays elongated, entirely covered with gill membrane. Anus situated just before anal-fin origin. Pectoral fin triangular, posterior tip pointed, dorsal, posterior, and ventral margins almost straight; fin insertion slightly posterior to posterior margin of opercle, lower than snout tip; posterior tip not reaching to pelvic-fin insertion; uppermost ray unbranched, others branched. Pelvic fin almost triangular, outer contours almost straight; posterior tip of depressed fin not reaching to vertical through dorsal-fin origin; anteriormost fin ray unbranched, others branched. Dorsal fin nearly triangular, anterior and dorsal profile nearly straight; fin origin located slightly anterior to middle of body; anterior three fin rays unbranched, others branched; first ray tiny. Anal-fin origin located just below 11th to 14th dorsal-fin ray origin; anterior three fin rays unbranched, others branched; first ray tiny; posterior tip of depressed fin not reaching to caudal-fin base. Caudal fin forked, posterior tips of both lobes pointed; anterior and posterior margins of both lobes nearly straight. Head without scales. Fins scaleless, except for broad triangular sheath of scales on caudal fin and elongated sheath of scales on bases of dorsal and anal fins. Body scales completely lost, except for prepelvic scutes.

Coloration of fresh specimens. Based on CSIRO H 6715-03, CSIRO H 7023-05, and CSIRO H 8965-01, frozen for 19 years before photography ( Fig. 5A, B ). Body milky-white, a silver longitudinal band (width slightly narrower than eye diameter) running through middle part of body. Silver band with narrow black margin dorsally. Cheek, opercle, and pectoral-fin axillary scale silver. Snout, maxilla, and pelvic-fin axillary scale transparent. Melanophores densely scattered on tips of snout and lower jaw, occipital area, dorsal margin of gill opening, middle of caudal-fin base, and dorsal surface of caudal peduncle. Scale pockets on dorsum posteriorly margined black. Melanophores scattered along fin rays of dorsal and caudal fins. No melanophores on lower margin of caudal fin. Posterior margin of caudal fin broadly black. Pectoral, pelvic, and anal fins translucent, without melanophores. Iris silver, pupil black.

Coloration of preserved specimens. Body uniformly pale, longitudinal band brownish (sometimes remaining silver) and dorsally margined black. Melanophores scattered on lateral surface of head (just above eye, upper margin of gill opening, and tips of maxilla and lower jaw). Pairs of dark patches on parietal and occipital regions. Few melanophores scattered on suborbital area and maxilla. Melanophores scattered along fin rays of dorsal and caudal fins. No melanophores on pectoral, pelvic, and anal fins, and lower margin of caudal fin. Scale pockets on dorsum margined black.

Distribution. Stolephorus waitei is known from the southeastern coast of New Guinea (Gulf of Papua) and the northern and northeastern coasts of Australia from off Cape Talbot, Western Australia (13°16′S, 127°05′E) to north of Bundaberg, Queensland (24°26′17.4″S, 152°04′30.0″E) ( Hata et al. 2019; this study: Fig. 3 ).

Remarks. Stolephorus waitei was described by Jordan & Seale (1926) based on a single specimen collected from Queensland, Australia. Although Whitehead et al. (1988) and Wongratana et al. (1999) regarded the species as widely distributed in the Indo-West Pacific, Hata et al. (2019) revealed that the name S. waitei should be applied for “ Stolephorus species A ” sensu Whitehead et al. (1988), an Australian endemic species. Additionally, the species treated as S. waitei by Whitehead et al. (1988) and Wongratana et al. (1999) has included at least five species (i.e., Stolephorus babarani Hata, Lavoué & Motomura, 2020a , Stolephorus bataviensis Hardenberg, 1933 , Stolephorus baweanensis Hardenberg, 1933 , Stolephorus celsior Hata & Motomura, 2021a , and Stolephorus concursus Hata & Motomura, 2021a ). These five species can easily be distinguished from the true S. waitei by having a long maxilla extending posteriorly slightly short of or just reaching posterior margin of opercle (vs. not reaching to posterior margin of preopercle in S. waitei ), longitudinal band on lateral surface of body silver or pale ivory, without black margin (vs. upper margin of longitudinal band black), numerous black spots on suborbital area in large individuals (vs. only few black spots), fewer gill rakers [41 or fewer (excepting S. concursus with 40–44 1TGR) vs. 41–44 in S. waitei ], pseudobranchial filaments [25 or fewer vs. 28–36 in individuals of S. waitei > 74 mm SL] and vertebrae [40 or fewer (rarely 41 in S. concursus and S. bataviensis )] ( Hata et al. 2019, 2020a; Hata & Motomura 2021a; this study). Due to taxonomic confusion, the exact distributional range of S. waitei has remained unresolved, and it has only been reliably recorded from south of Cooktown. The species is now apparently widely distributed in the Gulf of Papua and the northern and northeastern coasts of Australia from Cape Talbot, Western Australia to north of Bundaberg, Queensland ( Fig. 3 ).

Because fresh coloration of S. waitei has been unknown ( Hata et al. 2019), this study is the first to report the fresh coloration (see above). The black along the dorsal margin of the median longitudinal silver stripe, can separate the species from five species previously identified as S. waitei ( S. babarani , S. bataviensis , S. baweanensis , S. celsior , and S. concursus ; see above); this coloration is distinct both in fresh and preserved conditions ( Fig. 5A, B ).

As Whitehead et al. (1988) stated, S. waitei (as Stolephorus sp. A ) is “[p]resumed coastal, pelagic and schooling [but] more material and data needed,” so little biological information has been available for the species. Although most of the specimens described in this study were obtained from waters shallower than 30 m, a small number of specimens were also obtained from depths of 55 and 95 m. Unlike S. grandis , most specimens of S. waitei were usually collected tens of kilometers away from the shore, with only a few specimens obtained from river estuaries. Therefore, S. waitei is thought to rarely enter brackish waters.

As stated in the Remarks section for S. grandis , S. waitei is shown to be most closely related to S. grandis along with S. nelsoni rather than to S. babarani , S. bataviensis , and S. baweanensis , species that had been confused and compared to S. waitei in Hata et al. (2019). However, S. waitei can easily be distinguished from S. grandis by the lack of dark lines on the dorsum (vs. dark lines present in S. grandis ), more gill rakers (1TGR 41–44 in S. waitei vs. 35–39 in S. grandis ; Fig. 6 ) and pseudobranchial filaments (28–36 in individuals> 74 mm SL vs. 20–27), longer head (22.9–26.6% [usually> 24%] of SL vs. 22.0–24.0%), maxilla (17.9–20.4% of SL vs. 16.7–18.3%) and lower jaw (15.1–17.5% of SL vs. 14.3–15.3%), and shorter anal-fin base (12.9–16.9% of SL vs. 16.0–17.8%) ( Hata et al. 2019; Hata & Motomura 2021b; this study: Fig. 7 ). Additionally, S. waitei can be easily distinguished from S. nelsoni , a species thought to be also similar to S. waitei ( Fig. 1 ), by having shorter maxilla (17.9–20.4% of SL, posterior tip not reaching to posterior margin of preopercle in S. waitei vs. length 21.1–22.9%, posterior tip well beyond posterior margin of preopercle, more or less reaching posterior margin of opercle in S. nelsoni ), silver longitudinal line on lateral surface of body dorsally margined with narrow black line (vs. dark line absent on lateral surface), more pseudobranchial filaments (24–36 vs. 16–22), more longitudinal scale rows (36–41 vs. 34–36), more vertebrae (41 vs. 39–40), shorter pelvic fin (not reaching to vertical through dorsal-fin origin when depressed vs. reaching beyond vertical through dorsal-fin origin), shorter head (22.9–26.6% of SL vs. 26.3–28.4%), shorter jaw (15.1–17.5% of SL vs. 17.1–18.8%), shorter pectoral fin (13.7–14.9% of SL vs. 15.2–17.8%), narrower body (body depth 16.1–19.9% of SL vs. 21.0–24.2%; D–A 19.4–22.3% of SL vs. 22.5–26.4%), and absence of teeth on hyoid arch (vs. distinct conical teeth present on dorsal surface of ceratohyal) ( Hata et al. 2019; Hata & Motomura 2018d, 2021b, 2024c; this study).

Role of double lines on dorsum.Although the paired black lines on the dorsum anterior to the dorsal fin are known as a diagnostic character of five species of the genus Stolephorus , e.g., S. grandis , S. mercurius , S. multibranchus , S. rex , and Stolephorus tri ( Bleeker, 1852) ( Whitehead et al. 1988; Wongratana et al. 1999; Hata & Motomura 2018c, 2021b; Hata et al. 2019, 2021), these species do not form a monophyletic group in the phylogenetic tree shown in Figure 1 (no molecular data available for S. multibranchus ). Stolephorus grandis is more closely related to S. waitei and S. nelsoni , two species without double lines on the dorsum.

Additionally, some species of the genus such as Stolephorus baganensis Delsman, 1931 and Stolephorus eldorado Hata, Lavoué & Motomura, 2022b are known to have paired black longitudinal lines on the dorsum posterior to the dorsal fin ( Hata et al. 2019, 2022b). The role of black lines on dorsum in these species is unknown. However, we note that most species with black lines on the dorsum are commonly found in estuaries (e.g., Stolephorus dubiosus Wongratana, 1983 , S. mercurius , S. multibranchus , S. tri ; Delsman 1931; Hardenberg 1931, 1933, 1934; Hata & Motomura 2018c; Kimura et al. 1999; Tran et al. 2013; Nagao Natural Environment Foundation 2021) whereas species mainly inhabiting the marine pelagic environment, and rarely entering estuarine environments, have no dark lines on the dorsum (e.g., S. balinensis , S. bataviensis , S. waitei ; Whitehead et al. 1988; Wongratana et al. 1999; this study). Paired lines on the dorsum are also observed in other clupeiform fishes schooling in estuarine areas, such as Escualosa thoracata ( Valenciennes, 1847) , Thrissina katana Hata, Lavoué & Motomura, 2022a , and Thrissina malabarica ( Bloch, 1795) ( Whitehead 1985; Munroe et al. 1999; Rainboth et al. 2012; Hata et al. 2022a, 2023b). We hypothesize that the presence of black lines on the dorsum in Stolephorus and other clupeiforms are related to murky estuarine habitats where they can serve as a communication signal among individuals for identification or forming schools for activities such as feeding and spawning.

Comparative material examined. Stolephorus nelsoni : CSIRO H 6548-11 (tissue code: BW-A17755; BOLD accession number: FOAQ1056-24 ), 72.7 mm SL, approx. 6 km east of Deepwater , Queensland, Australia (24°26′S, 152°04′E), 14 m depth ; CSIRO H 7497-02 (BW-A17754; FOAQ1055-24 ), 63.1 mm SL, approx. 6 km northwest of Goold Island , Queensland, Australia (18°08′S, 146°06′E), 7 m depth .

Figures

FIGURE 1. Maximum-likelihood phylogenetic tree of 24 species of Stolephorus, based on the mitochondrial cytochrome c oxidase I (COI) gene (648 bp) of 45 specimens (ln L = −6315.919665). In this tree, each species of Stolephorus (when represented by two or more specimens) forms a monophyletic group. The name of the two species examined in detail in this study, S. grandis and S. waitei, are highlighted in bold. Each specimen of S. grandis, S. waitei, and S. nelsoni is identified by its CSIRO registration number followed in brackets by the tissue code, and BOLD and GenBank accession numbers of the COI sequence. Other specimens of Stolephorus are identified by corresponding museum registration number (if any) or GenBank number followed in brackets by specimen code (if any), and/or “GenBank” when the sequence was directly mined from this online database and, finally, species name. Two species of the genus Encrasicholina (the sister group of Stolephorus) are used as outgroups. Branch lengths proportional to number of substitutions. The scale represents 0.03 substitution/position. Bootstrap proportions (in %) indicated at corresponding nodes (except for the relationships within S. waitei).

FIGURE 3. Distributional records of Stolephorus grandis (red circles) and S. waitei (blue triangles), based on specimens examined in this study.

FIGURE 5. Fresh specimens (frozen for 19 years before imaging) of Stolephorus waitei from Queensland,Australia (A: CSIRO H 6715-03, 105.0 mm SL, B: CSIRO H 7023-05, 63.2 mm SL) and preserved specimen [lateral (C), dorsal (D), and ventral (E) views of NTM S.12989-004, 118.5 mm SL, Northern Territory, Australia].

FIGURE 6. Total gill-raker numbers on (A) first gill arch (1TGR), (B) second gill arch (2TGR), (C) third gill arch (3TGR), and (D) fourth gill arch (4TGR), and (E) pseudobranchial filaments relative to standard length in Stolephorus grandis (red circles) and S. waitei (blue triangles).

FIGURE 7. Relationships of (A) head length, (B) maxilla length, (C) lower-jaw length, and (D) anal-fin base length to standard length (SL) in Stolephorus grandis (red circles) and S. waitei (blue triangles).