A New Species of the Anchovy Genus Stolephorus Lacepède 1803 from North Sumatra, Indonesia, and Redescriptions of Stolephorus pacificus Baldwin 1984 and Stolephorus teguhi Kimura, Hori and Shibukawa 2009 (Teleostei: Clupeiformes: Engraulidae)

© 2021 Academia Sinica, Taiwan Open Access A New Species of the Anchovy Genus Stolephorus Lacepède 1803 from North Sumatra, Indonesia, and Redescriptions of Stolephorus pacificus Baldwin 1984 and Stolephorus teguhi Kimura, Hori and Shibukawa 2009 (Teleostei: Clupeiformes: Engraulidae) Harutaka Hata1,* and Hiroyuki Motomura2 1Center for Molecular Biodiversity Research, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan. *Correspondence: E-mail: [email protected] (Hata) 2The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan. E-mail: [email protected] (Motomura) Received 19 February 2021 / Accepted 28 July 2021 / Published 29 October 2021 Communicated by Felipe Ottoni Stolephorus leopardus sp. nov. is described here, and Stolephorus pacificus and Stolephorus teguhi are redescribed. Those three species are distinguished among congeners by the presence of more than 30 gill rakers on the lower limb of the first gill arch and a short maxilla, posteriorly just reaching the anterior border of the preopercle. Stolephorus pacificus and S. teguhi have rarely been reported since they were originally described, and therefore detailed morphological data and further diagnostic characters are provided. Stolephorus leopardus, in turn, is described based on four specimens collected on Nias Island, North Sumatra Province, Indonesia. The new species can be distinguished from S. pacificus and S. teguhi by a shorter pectoral fin (15.6–16.3% of standard length vs. longer than 16.5%), a longer snout (4.7–4.8% of standard length vs. < 4.5%), and an intermediate number of total gill rakers on the first gill arch (63–68 in S. leopardus vs. 57–63 in S. pacificus and 72–82 in S. teguhi). In addition, the new species differs from S. pacificus in having a dark line on the dorsum (vs. line absent), numerous melanophores laterally on the head (vs. a few melanophores on the snout and mandible tips), and higher counts of branched anal-fin rays [19–21(modally 19) vs. 17–19 (18)]. Stolephorus leopardus is further distinguished from S. teguhi by a shorter anal-fin base (22.4–22.5% of standard length vs. 22.7–25.3%). Key words: Clupeomorpha, Indian Ocean, Morphology, Southeast Asia, Taxonomy. Citation: Hata H, Motomura H. 2021. A new species of the anchovy genus Stolephorus Lacepède 1803 from North Sumatra, Indonesia, and redescriptions of Stolephorus pacificus Baldwin 1984 and Stolephorus teguhi Kimura, Hori and Shibukawa 2009 (Teleostei: Clupeiformes: Engraulidae). Zool Stud 60:65. doi:10.6620/ZS.2021.60-65. BACKGROUND The anchovy genus Stolephorus Lacepède 1803 (Clupeiformes: Engraulidae) currently includes 36 valid species that usually inhabit marine and/or estuarine waters in the Indo-Pacific region (Whitehead et al. 1988; Wongratana et al. 1999; Kimura et al. 2009; Hata and Motomura 2018a–e 2021a b; Hata et al. 2019 2020a b 2021; Gangan et al. 2020). Stolephorus pacificus Baldwin 1984 and Stolephorus teguhi Kimura, Hori and Shibukawa 2009 are distinguished from congeners by having more than 30 gill rakers on the lower limb of the first gill arch and a short maxilla, posteriorly just reaching the anterior margin of the preopercle (Baldwin Zoological Studies 60:65 (2021) doi:10.6620/ZS.2021.60-65 1 © 2021 Academia Sinica, Taiwan 1984; Whitehead et al. 1988; Wongratana et al. 1999, Kimura et al. 2009). During a revisionary study of the genus, four engraulid specimens from Nias Island, North Sumatra Province, Indonesia, also with numerous gill rakers and a short maxilla, were identified as a hitherto unknown species of Stolephorus, which is described herein. In addition, S. pacificus and S. teguhi are redescribed. MATERIALS AND METHODS Counts and measurements follow Hata and Motomura (2017), and are presented as percentage of standard length or head length. All measurements were made with digital calipers to the nearest 0.1 mm. “Pelvic scute” refers to the scute associated with the pelvic-fin insertion, whereas “prepelvic”, “postpelvic”, and “predorsal scutes” refer to the scutes anterior to the pelvic scute, posterior to the pelvic scute, and just anterior to the dorsal-fin origin, respectively. All specimens were examined in this study, except for the holotype of S. teguhi, from which anatomical data were obtained from Kimura et al. (2009). Abbreviations are as follows—SL: standard length; HL: head length; UGR, LGR and TGR: rakers on upper limb, lower limb and total gill rakers, respectively, with numbers associated indicating the specific gill arch; and SMX-MX: distance between posterior margins of supramaxilla and maxilla. Institutional abbreviations follow Sabaj (2020). RESULTS Stolephorus pacificus Baldwin 1984 (English name: Pacific Anchovy) (Fig. 1; Tables 1–3) Stolephorus pacificus Baldwin 1984: 152, fig. 1 (type locality: Acfayan Bay, Guam; paratype localities: Talofofo Bay, Guam and Coquille Harbor, Kosrae); Wongratana 1987: 7 (Guam and Kosrae); Whitehead et al. 1988: 417, unnumbered fig. (Guam and Kosrae); Myers 1999: 62, fig. 1h (Guam and Kosrae); Wongratana et al. 1999: 1739, unnumbered fig. (Guam and Kosrae); Myers and Donaldson 2003: 609 (Guam); Kimura et al. 2009: 295, fig. 1c (Acfayan Bay, Guam); Hata et al. 2021: 368 (Acfayan Bay, Guam). Holotype: BPBM 28190, 54.6 mm SL, Acfayan Bay, Guam, 14 Jan. 1970. Paratypes: 26 specimens, 28.4–64.9 mm SL. BMNH 1983.2.3.1–4, 4 specimens, 49.2–54.1 mm SL, Acfayan Bay, Guam, 12 Nov. 1971; BPBM 25405, 64.9 mm SL, Talofofo Bay, Guam, 14 Mar. 1948; BPBM 28191, 10 specimens, 28.4–55.3 mm SL, Acfayan Bay, Guam, 14 Jan. 1970; BPBM 28782, body broken, Coquille Harbor, Kosrae, 1.5 m depth, 25 June 1971; USNM 263476, 10 specimens, 48.4–59.9 mm SL, Talofofo Bay, Guam, 13 Mar. 1948. Diagnosis: A species of Stolephorus with the following combination of characters: 1UGR 21–26, 1LGR 32–38, 1TGR 57–62; 2UGR 18–20, 2LGR 29–35, 2TGR 47–53; 3UGR 13–15, 3LGR 17–20, 3TGR 30–35; 4UGR 10–12, 4LGR 13–15, 4TGR 23–27; prepelvic scutes 1–4; short maxilla, its posterior tip just reaching or slightly short of preopercle anterior margin, 13.8–18.1% of SL; no predorsal scutes; pelvic scute without spine; posterior border of preopercle convex, rounded; distinct paired dark patches on parietal area; obvious dark patch on occipital region; no lines of pigment on dorsum; melanophores absent on lateral head surface, a few scattered on tips of snout and lower jaw; posterior tip of pelvic fin reaching to vertical through second to fifth dorsal-fin ray base; SMX-MX 10.2–16.8% of maxilla length (13.6–16.8% in specimens > 48.4 mm SL); postorbital length 48.5– 53.3% of HL; snout long, 4.4–4.8% of SL; pectoral fin long, 16.5–18.3% of SL. Description: Data for holotype presented first, followed by paratype data in parentheses (if different). Measurements and counts are presented in tables 1 and 2. Body compressed laterally, elongated, deepest at dorsalfin origin. Dorsal profile gently elevated from snout tip to dorsal-fin origin, thereafter lowering to caudal-fin base. Ventral profile lowering from snout tip to pelvicfin insertion, thereafter elevating to caudal-fin base. Abdomen rounded, with four (one to four) needle-like prepelvic scutes. Predorsal and postpelvic scutes absent. Pelvic scute without spine. Anus situated just anterior to anal-fin origin. Caudal peduncle compressed. Snout tip rounded; snout length less than eye diameter. Mouth large, inferior, ventral to body axis, extending backward beyond posterior margin of eye. Lower jaw slender. Maxilla short, its posterior tip pointed, just reaching to anterior border of preopercle (just short of anterior border of preopercle in some paratypes). Single row of conical teeth on each jaw and palatines. Small conical teeth in patch on vomer. Eye large, round, positioned laterally on head, and dorsal to horizontal through upper margin of pectoral-fin insertion, visible in dorsal view. Pupil round. Orbit elliptical. Nostrils close to each other, anterior to orbit. Posterior margins of preopercle and opercle smooth. Subopercle with rounded posterior margin. Opercular membrane without serrations. Interorbital space flat. Interorbital width less than eye diameter. Pseudobranchial filaments present, length of longest filament less than eye diameter. Gill rakers long, slender, rough, visible from side of head when mouth opened. Isthmus muscle long, reaching anteriorly to page 2 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan posterior margin of gill membranes. Urohyal hidden by isthmus muscle, not visible without dissection. Gill membrane on each side joined anteriorly, isthmus muscle mostly exposed, not covered by gill membrane. Scales cycloid, thin, deciduous, absent on head. Scales on fins completely lacking on specimens except for alar scales on caudal fin. Lateral line absent. Anteriormost point of pelvic-fin insertion anterior to middle of body. Posterior tip of depressed pelvic fin reaching to vertical through fifth (second to fifth) dorsal-fin ray base. Dorsal and anal fins each with minute first ray, three anteriormost rays unbranched. Anal-fin origin just below origin of eighth (eighth to eleventh) dorsal-fin ray. Uppermost pectoral-fin ray unbranched, inserted below midline of body; posterior tip of fin not reaching to vertical through pelvic-fin insertion. Coloration of preserved specimens: Body uniformly pale brown, a pale ivory longitudinal band, its width slightly less than pupil diameter, extending from just upper opercular margin to caudal-fin base. A pair of dark patches behind occiput without a following pair of dark lines. Melanophores scattered on bases of dorsal and anal fins, and posterior margins of scales on dorsum, caudal-fin rays, and anterior dorsal-fin rays; absent on lateral surface of head; present on ventral surface of body from end of anal-fin base to caudal-fin base. Live and fresh coloration unknown. Distribution: Currently known only from Guam, Mariana Islands and Kosrae, Caroline Islands (Baldwin 1984; Whitehead et al. 1988; this study; Fig. 2). Fig. 1. (A) Lateral and (B) dorsal views of the holotype of Stolephorus pacificus. BPBM 28190, 54.6 mm SL, Acfayan Bay, Guam. A B Fig. 2. Records of Stolephorus pacificus (triangles), S. teguhi (squares), and S. leopardus sp. nov. (circles), based on specimens examined in this study. page 3 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan Comparisons: Stolephorus pacificus is easily distinguished from congeners, except Stolephorus advenus Wongratana 1987, Stolephorus balinensis (Bleeker 1849), Stolephorus belaerius Hata, Lavoué and Motomura 2021, Stolephorus commersonnii Lacepède 1803, Stolephorus indicus (van Hasselt 1823), Stolephorus scitulus (Fowler 1911), S. teguhi and S. leopardus by having a short maxilla, posteriorly just reaching to the preopercle anterior margin. It also differs from those species, except S. teguhi and S. leopardus, in having more than 31 gill rakers on the first gill arch (vs. less than 29 in S. teguhi and S. leopardus) and the pelvic fin extending posteriorly beyond the vertical through the dorsal-fin origin (vs. anterior to dorsal-fin origin) (Whitehead et al. 1988; Wongratana et al. 1999; Kimura et al. 2009; Hata and Motomura 2018a–e 2021a b; Hata et al. 2019 2020a b 2021; Gangan et al. 2020). In the original description of S. teguhi, Kimura et al. (2009) compared S. pacificus with their new species, stating that the ratio of SMX-MX (13.4–16.2% of maxilla length in S. pacificus vs. 6.6–12.7% in S. teguhi) and postorbital length (51.1–54.9% of HL vs. 55.4–59.1%) separated the two species [based on the type specimens of S. teguhi (49–77 mm SL) and S. pacificus (> 45 mm)]. However, our examination of small specimens of S. teguhi (40.3 mm) and S. pacificus (28.4–41.1 mm SL) revealed that such ratios failed to clearly separate the two species, the smaller specimens being characterized by overlapping ratios (SMX-MX: 11.2–11.7% of maxilla length in S. pacificus; postorbital length: 50.7% of HL in S. teguhi; Table 1; Fig. 3). However, specimens > 45 mm SL of the two species can be separated by the ratios proposed by Kimura et al. (2009) (SMX-MX: 13.6–16.8% of maxilla length in S. pacificus vs. 6.3–12.2% in S. teguhi; postorbital length: 48.5–53.3% of HL vs. 53.8–58.2%; Fig. 3). Furthermore, S. pacificus is easily distinguished from S. teguhi by having lower counts of gill rakers on the first, second, third, and fourth gill arches (Table 2; Fig. 4), branched anal-fin rays [17–19 (modally 18) vs. 19–21 (19); Table 3], and the dorsum without dark lines (vs. a dark line present; Figs. 1B, 5C) (Kimura et al. 2009; Hata and Motomura 2018b; this study). A detailed comparison of S. pacificus and S. leopardus sp. nov. is given under the description of the latter. Remarks: Stolephorus pacificus was described by Baldwin (1984) on the basis of 44 specimens collected from Guam, Micronesia and Kosrae Island, Caroline Islands. Subsequently, Kimura et al. (2009) examined the holotype and 24 paratypes of S. pacificus for comparison with their new species, S. teguhi. Since its description, no additional specimens of S. pacificus have been found, and the species is still known only from the type specimens. Stolephorus teguhi Kimura, Hori and Shibukawa 2009 (English name: Sulawesi Anchovy) (Fig. 5; Tables 1–3) Stolephorus teguhi Kimura et al. 2009: 292, fig. 1a, b, 3 (type locality: Pintu Kota, Lembeh I., North Sulawesi, Indonesia; paratype localities: Tanjung Merah, Bitung, North Sulawesi, Indonesia); Hata and Motomura 2018b: 21, fig. 1 (Pagapas Bay, Luzon, Philippines). Holotype: MZB 17.282, 69 mm SL [counts and measurements cited from the original description, Kimura et al. (2009)], Pintu Kota, Lembeh Island, North Sulawesi, Indonesia, 20 Jan. 2000, beach seine, coll. by K. Matsuura, S. Kimura and T. Peristiwady. Paratypes: 14 specimens, 50.1–77.8 mm SL. AMS-I. 44677-001, 55.9 mm SL, BMNH 2008.9.22.2, 65.2 mm SL, BPBM 40921, 65.1 mm SL, FRLM 25583, 61.9 mm SL, FRLM 25802, 51.6 mm SL, FRLM 25803, 50.1 mm SL, FRLM 26462, 63.4 mm SL, NSMT-P 91708, 75.3 mm SL, NSMT-P 91709, 73.8 mm SL, NSMT-P 91710, 70.0 mm SL, Pintu Kota, Lembeh Island, North Sulawesi, Indonesia, collected with beach seine; FRLM 24609, 71.0 mm SL, FRLM 24777, 77.8 mm SL, MNHN 2008-1932, 74.9 mm SL, RMNH. PISC 84067, 69.4 mm SL, Tanjung Merah, Bitung, North Sulawesi, Indonesia, collected with beach seine. Fig. 3. Relationships of (A) distance between posterior ends of supramaxilla and maxilla (SMX-MX) (as % of maxilla length; MX) and (B) postorbital length (as % of head length) to standard length in Stolephorus pacificus (triangles), S. teguhi (squares), and S. leopardus sp. nov. (circles). page 4 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan Non-type specimens: 7 specimens, 40.2–68.9 mm SL. FRLM 34849, 68.9 mm SL, FRLM 34850, 60.8 mm SL, FRLM 34851, 65.5 mm SL, FRLM 34852, 61.0 mm SL, FRLM 34853, 66.5 mm SL, Pintu Kota, Lembeh Island, North Sulawesi, Indonesia, collected with beach seine; KAUM–I. 43983, 40.2 mm SL, Labuhan Kompeni, Lembeh Island, North Sulawesi, Indonesia, collected with beach seine; USNM 138538, 59.7 mm SL, Pagapas Bay, Batangas Province, Luzon, Philippines, 1 m depth, seine net. Diagnosis: A species of Stolephorus with the following combination of characters: 1UGR 31–36, 1LGR 41–46, 1TGR 72–82; 2UGR 22–26, 2LGR 37– 41, 2TGR 60–67; 3UGR 16–19, 3LGR 20–25, 3TGR 36–43; 4UGR 12–13, 4LGR 14–17, 4TGR 26–30; prepelvic scutes 2–5; short maxilla, its posterior tip just reaching or slightly short of preopercle anterior margin, 15.4–17.6% of SL; no predorsal scutes; pelvic scute Table 1. Morphometrics of specimens of Stolephorus pacificus, S. teguhi, and S. leopardus sp. nov. Stolephorus pacificus Stolephorus teguhi Stolephorus leopardus sp. nov. Holotype Paratypes Holotype* Paratypes Non-types Holotype Paratypes BPBM 28190 n = 25 MZB 17.282 n = 14 n = 7 RMNH.PISC. 84312 n = 3 Standard length (mm; SL) 54.6 28.4–64.9 Means 69 50.1–77.8 40.2–68.9 Means 64.6 65.0–71.5 Means As % of SL Head length (HL) 24.7 24.1–26.4 25.2 25.1 23.6–26.7 25.5–27.2 25.7 26.4 25.5–25.9 25.9 Body depth 21.3 17.5–22.2 19.6 21.4 20.2–22.7 19.7–21.3 21.2 21.4 19.5–21.0 20.7 Pre-dorsal fin length 52.9 49.0–56.9 54.3 53.5 50.6–55.4 54.0–57.4 54.5 55.7 56.4–57.4 56.6 Snout tip to pectoral-fin insertion 28.1 24.5–29.1 26.8 26.8 26.1–28.7 26.8–28.2 27.4 27.6 26.5–27.7 27.3 Snout tip to pelvic-fin insertion 46.2 44.0–47.4 45.4 44.8 44.7–47.9 44.8–48.4 46.3 44.7 44.6–44.9 44.7 Snout tip to anal-fin origin 64.5 54.4–65.6 63.0 63.4 62.3–66.3 62.8–65.5 64.4 62.2 62.4–63.8 62.8 Dorsal-fin base length 15.4 14.1–16.7 15.3 15.0 13.2–15.8 13.1–15.5 14.6 13.2 14.1–14.8 14.2 Anal-fin base length 21.8 18.9–22.8 20.8 23.5 22.7–25.3 22.8–24.3 23.4 22.4 22.5 22.5 Caudalpeduncle length 13.8 14.0–17.4 15.6 16.2 14.0–16.3 14.2–15.6 15.3 16.5 13.9–15.7 15.4 Caudal-peduncle depth 10.3 8.4–11.3 9.7 9.5–10.9 9.3–10.5 10.1 11.1 9.3–10.2 10.1 D–P1 33.8 32.8–36.0 34.6 33.7–38.2 34.4–37.6 35.9 34.6 35.2–35.6 35.2 D–P2 22.7 20.1–23.4 21.9 22.9–25.4 22.1–25.0 23.8 24.4 22.4–24.5 23.8 D–A 22.8 19.8–23.0 21.6 21.9–23.5 21.1–23.6 22.5 22.4 21.2–22.2 21.8 P1–P2 19.7 17.5–23.4 19.8 19.7–22.8 17.7–22.2 20.7 18.1 18.1–19.7 18.7 P2–A 17.7 15.4–19.1 17.6 16.3–21.4 17.0–20.2 18.6 18.1 17.5–18.1 17.9 Pectoral-fin length broken 16.5–18.3 17.3 17.5 16.5–18.8 17.0–18.5 17.5 16.3 15.6–16.3 16.1 Pelvic-fin length 11.6 10.2–13.0 11.4 11.4 10.6–12.6 9.8–11.8 11.2 11.0 10.1 10.3 Snout length 4.4 3.5–4.3 4.0 5.5** 3.7–4.4 3.8–4.5 4.0 4.8 4.7–4.8 4.7 Maxilla length 17.7 13.8–18.1 16.6 16.6 15.4–17.5 16.4–17.6 16.8 17.6 17.3–17.5 17.5 Lower-jaw length 16.4 15.5–17.4 16.3 16.0–17.9 16.2–17.9 16.7 17.3 16.5–17.3 17.1 Supramaxilla end to maxilla end 2.9 1.4–2.9 2.4 1.0–2.3 1.4–2.0 1.7 2.2 1.4–2.0 1.9 1st unbranched dorsal-fin ray length 1.3 0.9–3.2 1.7 2.0–2.6 1.4–3.1 2.4 2.4 0.8–2.3 1.9 2nd unbranched dorsal-fin ray length broken 7.1–9.6 8.3 7.7–9.5 8.9–9.4 8.8 broken 7.4–7.7 7.6 3rd dorsal-fin ray length broken 18.4–20.4 19.4 1st unbranched anal-fin ray length 1.4 0.9–2.0 1.5 2.0–2.6 1.4–3.1 2.4 2.4 0.8–2.3 1.9 2nd unbranched anal-fin ray length broken 4.2–6.7 5.7 7.7–9.5 8.9–9.4 8.8 broken 7.4–7.7 7.6 3rd anal-fin ray length broken 12.1–15.3 14.0 12.0–15.3 14.4–15.1 14.3 broken 13.1–13.3 13.2 As % of HL Orbit diameter 36.3 31.6–37.6 34.4 29.4–35.2 31.5–33.5 32.3 29.2 31.1–32.0 31.0 Eye diameter 26.2 21.5–29.5 25.7 25.6 22.7–28.6 27.4–29.9 27.1 24.4 24.5–27.4 25.7 Snout length 17.8 14.6–17.0 16.0 22.1** 14.6–18.3 14.5–17.2 15.7 18.1 18.1–18.4 18.2 Interorbital width 23.4 19.8–25.7 23.5 22.8–26.4 22.7–25.1 24.0 23.7 21.9–23.5 23.0 Postorbital length 49.3 48.5–53.3 50.5 57.0 53.8–58.2 50.7–57.8 55.2 54.2 54.4–56.2 54.9 As % of maxilla length Supramaxilla end to maxilla end 16.6 10.2–16.8 14.5 7.0 6.3–12.2 8.7–11.5 10.0 10.5 8.1–10.8 9.8 Abbreviations: D–P1 (distance from dorsal-fin origin to pectoral-fin insertion); D–P2 (distance from dorsal-fin origin to pelvic-fin insertion); D–A (distance between origins of dorsaland anal fins); P1–P2 (distance between insertions of pectoraland pelvic fins); P2–A (distance between pelvicfin insertion to anal-fin origin). *Data from Kimura et al. (2009). **Probably based on measurement error (see Remarks of S. teguhi). page 5 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan Fig. 4. Relationships of total gill raker numbers (TGR) on (A) first gill arch (1GA), (B) second gill arch (2GA), (C) third gill arch (3GA), and (D) fourth gill arch (4GA) to standard length in Stolephorus pacificus (triangles), S. teguhi (squares), and S. leopardus sp. nov. (circles). A B C Fig. 5. (A) Lateral view of a non-type specimen of Stolephorus teguhi (fresh condition), KAUM–I. 43983, 40.2 mm SL, Lembeh Island, North Sulawesi, Indonesia; lateral (B) and dorsal (C) views of the paratype of Stolephorus teguhi, NSMT-P 91709, 73.8 mm SL, Lembeh Island, North Sulawesi, Indonesia. page 6 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan without spine; posterior border of preopercle convex, rounded; distinct paired dark patches on parietal and occipital regions; single dark line on dorsum from occipital region to upper margin of caudal-fin base; numerous black spots on snout and both upper and lower jaws; scales on dorsum with black margin; posterior tip of pelvic fin reaching to vertical through second to seventh dorsal-fin ray base; SMX-MX 6.3– 12.2% of maxilla length; postorbital length 50.7–58.2% of HL(53.8–58.2% in specimens > 50 mm SL); snout short, 3.7–4.5% of SL; pectoral fin long, 16.5–18.8% of SL. Description: Measurements and counts are presented in tables 1 and 2. Body compressed laterally, elongated, deepest at dorsal-fin origin. Dorsal profile gently elevated from snout tip to dorsal-fin origin, thereafter lowering to caudal-fin base. Ventral profile decreasing from snout tip to pelvic-fin insertion, thereafter elevating to caudal-fin base. Abdomen rounded, with two to five needle-like prepelvic scutes. Predorsal and postpelvic scutes absent. Pelvic scute without spine. Anus located just anterior to analfin origin. Caudal peduncle compressed. Snout tip rounded, snout length less than eye diameter. Mouth large, inferior, ventral to body axis, extending backward beyond posterior margin of eye. Lower jaw slender. Maxilla short, its posterior tip pointed, just reaching to anterior border of preopercle. Single row of conical teeth on each jaw and palatines. Small conical teeth in patch on vomer. Eye large, round, positioned laterally on head and dorsal to horizontal through upper point of pectoral-fin insertion, visible in dorsal view. Pupil round. Orbit elliptical. Nostrils close to each other, anterior to orbit. Posterior margins of preopercle and opercle smooth. Subopercle with rounded posterior margin. Opercular membrane without serrations. Interorbital space flat. Interorbital width less than eye diameter. Pseudobranchial filaments present, length of Table 2. Meristics of specimens of Stolephorus pacificus, S. teguhi, and S. leopardus sp. nov. Stolephorus pacificus Stolephorus teguhi Stolephorus leopardus sp. nov. Holotype Paratypes Holotype* Paratypes Non-types Holotype Paratypes BPBM 28190 n = 25 MZB 17.282 n = 14 n = 7 RMNH.PISC. 84312 n = 3 Standard length (mm) 54.6 28.4–64.9 Modes 69 50.1–77.8 40.2–68.9 Modes 64.6 65.0–71.5 Modes Dorsal-fin rays (unbranched) 3 3 3 3 3 3 3 3 3 3 Dorsal-fin rays (branched) 13 12–14 13 12 12 11–12 12 11 12 12 Anal-fin rays (unbranched) 3 3 3 3 3 3 3 3 3 3 Anal-fin rays (branched) 19 17–19 18 20 19–21 19–21 19 19 19–21 19 Pectoral-fin rays (unbranched) 1 1 1 1 1 1 1 1 1 1 Pectoral-fin rays (branched) 12 11–14 12 12 12–13 12–13 13 13 12–13 13 Pelvic-fin rays (unbranched) 1 1 1 1 1 1 1 1 1 1 Pelvic-fin rays (branched) 6 6 6 6 6 6 6 6 6 6 Caudal-fin rays 19 19 19 19 19 19 19 19 19 19 Gill rakers on 1st gill arch (upper) 25 21–26 25 32 31–36 31–35 31 29 26–28 28 Gill rakers on 1st gill arch (lower) 35 32–38 36 44 41–46 41–43 42 39 37–39 39 Gill rakers on 1st gill arch (total) 60 57–63 58 76 73–82 72–78 74 68 63–67 - Gill rakers on 2nd gill arch (upper) 20 17–20 18 22–26 22–23 23 22 19–21 - Gill rakers on 2nd gill arch (lower) 30 29–35 31 37–41 37–40 38 37 34–36 - Gill rakers on 2nd gill arch (total) 50 47–53 50 60–67 60–63 61 59 54–57 54 Gill rakers on 3rd gill arch (upper) 15 13–16 14 16–19 16–8 17 16 14–16 16 Gill rakers on 3rd gill arch (lower) 18 17–20 18 20–25 20–21 20 21 19–21 21 Gill rakers on 3rd gill arch (total) 33 30–35 32 36–43 36–38 39 37 33–37 37 Gill rakers on 4th gill arch (upper) 11 10–12 11 12–13 12–13 12 10 10–11 10 Gill rakers on 4th gill arch (lower) 15 13–15 14 14–17 14–16 15 15 14–15 15 Gill rakers on 4th gill arch (total) 26 23–27 25 26–30 26–28 27 25 24–26 25 Gill rakers on posterior face of 3rd gill arch 85–8 64–9 5–7 65 4–5 5 Prepelvic scutes 4 1–3 3 3 2–5 3–4 4 33–4 3 Scale rows in longitudinal series 35 34–37 35 36 34–37 34–37 34 33 33–34 33 Transverse scales 8 8 8 8 8–9 8 8 8 8 Pseudobranchial filaments 17 15–21 17 16–20 17–19 17 18 18 18 *Data from Kimura et al. (2009). page 7 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan longest filament less than eye diameter. Gill rakers long, slender, rough, visible from side of head when mouth opened. Isthmus muscle long, reaching anteriorly to posterior margin of gill membranes. Urohyal hidden by isthmus muscle, not visible without dissection. Gill membrane on each side joined anteriorly, isthmus muscle mostly exposed, not covered by gill membrane. Scales cycloid, thin, deciduous, absent on head and fins, except for alar scales. Lateral line absent. Anteriormost point of pelvic-fin insertion anterior to middle of body. Posterior tip of depressed pelvic fin reaching to vertical through second to seventh dorsal-fin ray origin. Dorsal and anal fins each with minute first ray, three anteriormost rays unbranched. Anal-fin origin just below origin of seventh to tenth dorsal-fin ray. Uppermost pectoral-fin ray unbranched, inserted below midline of body; posterior tip of fin not reaching to vertical through pelvic-fin insertion. Coloration of fresh specimens: [Based on color photographs of two specimens (FRLM 26462 and KAUM–I. 43983)]. Body silvery-white, a longitudinal silver band narrower than pupil diameter extending from just behind upper opercular margin to caudal-fin base. Lateral surface of head almost uniformly silver, snout semi-translucent. Melanophores densely scattered on dorsum of head. Fin rays translucent, pectoral and caudal fins slightly yellowish. Melanophores present on fin rays of dorsal, pectoral, and caudal fins, and bases of dorsal and anal fins. Scale pockets on dorsum darkly margined. Coloration of preserved specimens: Body uniformly pale, a longitudinal band of melanophores narrower than pupil diameter, from just behind upper opercular margin to caudal-fin base. Pairs of distinct dark patches on parietal and occipital regions. A narrow dark line running from occipital region to upper margin of caudal-fin base. Melanophores densely distributed on dorsal surface of head, snout tip, both of upper and lower jaws, and upper parts of anterior margin of preopercle and posterior margin of gill opening. Scale pockets on dorsum darkly margined. All fins semitranslucent. Melanophores present on fin rays of dorsal, pectoral, and caudal fins, and on anterior parts of pelvic and anal fins, bases of dorsal and anal fins, and ventral surface of body from end of anal-fin base to caudal-fin base. Distribution: Currently known only from Lembe Island and Bitung, North Sulawesi, Indonesia and Pagapas Bay, Batangas Province, Luzon, Philippines (Kimura et al. 2009; Hata and Motomura 2018b; this study; Fig. 2). Comparisons: The gill raker numbers on first, second, third, and fourth gill arches in this species are the highest recorded in the genus, with no congeneric species having more than 40 gill rakers on the lower limb of the first gill arch (Whitehead et al. 1988; Wongratana et al. 1999; Kimura et al. 2009; Hata and Motomura 2018a–e 2021a b; Hata et al. 2019 2020a b 2021; Gangan et al. 2020; this study). Detailed comparisons of S. teguhi with S. pacificus and S. leopardus sp. nov. (described below) are given under “Comparisons” for each species. Although S. teguhi is similar to Stolephorus babarani Hata, Lavoué and Motomura 2020, Stolephorus bataviensis Hardenberg 1933, Stolephorus baweanensis Hardenberg 1933, and Stolephorus waitei Jordan and Seale 1926 in sharing scattered melanophores on the snout and both upper and lower jaws, the former is easily distinguished from the others by having a short maxilla, its posterior tip just reaching the preopercle anterior margin, 15.4–17.6% of SL (vs. beyond or slightly short of posterior margin and > 17.9% of SL in in the others), and higher gill raker count on 1LGR (vs. fewer than 26) (Hata et al. 2019 2020a; this study). Remarks: Stolephorus teguhi was originally described by Kimura et al. (2009) based on 15 specimens collected from Lembe Island and Bitung, North Sulawesi, Indonesia. The snout length proportion for the holotype of S. teguhi given by Kimura et al. (2009) (5.6% of SL) is likely based on a measurement error, because specimens examined in this study have a range between 3.7–4.4% for that character. Subsequently, Hata and Motomura (2018c) reported the species from Pagapas Bay, Batangas Province, Luzon, Philippines. Hata and Motomura (2018c) also suggested that the species is widely distributed from the Celebes Sea to the eastern part of the South China Sea, but no specimens supporting that suggestion have been recorded so far. Stolephorus leopardus sp. nov. (New English name: Leopard Anchovy) (Fig. 6; Tables 1–3) urn:lsid:zoobank.org:act:16BEE9A0-A409-4718-82221A70010BDF47 Holotype: RMNH.PISC.84312, 64.6 mm SL, Lahewa, Nias Island, Indonesia. Paratypes: 3 specimens, 65.0–71.5 mm SL. RMNH.PISC.84313, 71.5 mm SL, RMNH.PISC.84314, 65.0 mm SL, RMNH.PISC.84315, 65.9 mm SL, collected with the holotype. Diagnosis: A species of Stolephorus with the following combination of characters: 1UGR 26–29, 1LGR 37–39, 1TGR 63–68; 2UGR 19–22, 2LGR 34– 37, 2TGR 54–59; 3UGR 14–16, 3LGR 19–21, 3TGR 33–37; 4UGR 10–11, 4LGR 14–15, 4TGR 24–26; gill rakers on posterior face on third gill arch 4–5; prepelvic page 8 of 13Zoological Studies 60:65 (2021) © 2021 Academia Sinica, Taiwan scutes 3–4; short maxilla, posterior tip just reaching or slightly short of anterior margin of preopercle, 17.3– 17.6% of SL; no predorsal scutes; pelvic scute without spine; posterior border of preopercle convex, rounded; distinct paired dark patches on parietal and occipital regions; single dark line on dorsum from occipital area to upper portion of caudal-fin base; numerous black spots on snout and both upper and lower jaws; scales on dorsum with black margin; posterior tip of pelvic fin reaching to vertical through third to fifth dorsal-fin ray base; anal-fin base short, 22.4–22.5% of SL; pectoral fin short, 15.6–16.3%; SMX-MX 8.1–10.8% of maxilla length; postorbital length 54.2–56.2% of HL; snout long, 4.7–4.8% of SL. Description: Data for holotype presented first, followed by paratype data in parentheses (if different). Measurements and counts are presented in tables 1 and 2. Body compressed laterally, elongated, deepest at dorsalfin origin. Dorsal profile gently elevated from snout tip to dorsal-fin origin, thereafter lowering to caudal-fin base. Ventral profile decreasing from snout tip to pelvicfin insertion, thereafter elevating to caudal-fin base. Abdomen rounded, with three (three or four) needlelike prepelvic scutes. Predorsal and postpelvic scutes absent. Pelvic scute without spine. Anus situated just anterior to anal-fin origin. Caudal peduncle compressed. Snout tip rounded; snout length less than eye diameter. Mouth large, inferior, ventral to body axis, extending backwards beyond posterior margin of eye. Lower jaw slender. Maxilla short, its posterior tip pointed, just reaching to anterior border of preopercle. Single row of conical teeth on jaws and palatines. Small conical teeth in patch on vomer. Eye large, round, positioned laterally on head dorsal to horizontal through upper point of pectoral-fin insertion, visible in dorsal view. Pupil round. Orbit elliptical. Nostrils close to each other, anterior to orbit. Posterior margins of preopercle and opercle smooth. Subopercle with rounded posterior margin. Opercular membrane without serrations. Interorbital space flat. Interorbital width less than eye diameter. Pseudobranchial filaments present, length of longest filament less than eye diameter. Gill rakers long, slender, rough, visible from side of head when mouth opened. Isthmus muscle long, reaching anteriorly to posterior margin of gill membranes. Urohyal hidden by isthmus muscle, not visible without dissection. Gill membrane on each side joined anteriorly, isthmus muscle mostly exposed, not covered by gill membrane. Lateral line absent. Anteriormost point of pelvic-fin insertion anterior to middle of body. Posterior tip of depressed pelvic fin reaching to vertical through third (third or fourth) dorsal-fin ray base. Dorsal and anal fins each with minute first ray, three anteriormost rays unbranched. Anal-fin origin just below base of seventh (eighth to ninth) dorsal-fin ray. Uppermost pectoralfin ray unbranched, inserted below midline of body; posterior tip of fin not reaching to vertical through pelvic-fin insertion. Coloration of preserved specimens: Body uniformly pale brown; a light pale longitudinal band, slightly narrower than pupil diameter, from just behind upper opercular margin to caudal-fin base. Pairs of distinct dark patches on parietal and occipital regions. A dark line running from occipital region to upper portion of caudal-fin base. Melanophores densely distributed on dorsal surface of head, snout tip, both jaws, upper part of anterior margin of preopercle, and posterior margin of gill opening. All fins semi-translucent. Melanophores present on fin rays of dorsal, pectoral, and caudal fins, and on anterior parts of pelvic and anal fins, and ventral Fig. 6. (A) Lateral and (B) dorsal views of the holotype of Stolephorus leopardus sp. nov. RMNH.PISC.84312, 64.6 mm SL, Nias Island, west of Sumatra, Indonesia. A B page 9 of 13Zoological Studies 60:65 (2021)