Sardinella alcyone, Hata & Motomura, 2019

Hata, Harutaka & Motomura, Hiroyuki, 2019, Sardinella alcyone n. sp., a new sardine (Teleostei: Clupeiformes: Clupeidae) from the northwestern Pacific Ocean, Zootaxa 4702 (1), pp. 19-25 : 19-23

publication ID

https://doi.org/ 10.11646/zootaxa.4702.1.6

publication LSID

lsid:zoobank.org:pub:833FCD58-12A5-4D9A-A91C-895EA854CD98

persistent identifier

https://treatment.plazi.org/id/0392814C-E909-FFC3-FF4E-F88DFD117CF3

treatment provided by

Plazi

scientific name

Sardinella alcyone
status

sp. nov.

Sardinella alcyone n. sp.

[New English name: Blueback Sardinella ; new standard Japanese name: Shiosai-iwashi]

Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 ; Table 1 View TABLE 1

Holotype. KAUM–I. 108333, 96.1 mm SL, mouth of Nasada River , Nago , Okinawa Island, Ryukyu Islands, Japan, 26°38′05″N, 128°00′07″E, 1 m depth, 12 Mar. 2017, casting net, K. Shibukawa & M. Nakae. GoogleMaps

Paratypes. 18 specimens, 66.6–109.8 mm SL. JAPAN: KAUM–I. 108334, 78.4 mm SL, KAUM–I. 108336, 79.3 mm SL, SPMN-NI 44303 , 77.4 mm, SPMN-PI 44304 , 73.9 mm SL, SPMN-PI 44305 , 79.9 mm SL, SPMN- NI 44306 , 66.6 mm SL, collected with the holotype; KAUM–I. 108335, 72.2 mm SL, same locality as holotype, collected in 11 Mar. 2017; URM-P 41020 , 81.5 mm SL, URM-P 41021 , 90.8 mm SL, URM-P 41022 , 89.4 mm SL, URM-P 41023 , 98.2 mm SL, URM-P 41024, 106.5 mm SL, URM-P 41025, 103.5 mm SL, Nakaoji, Haneji, Okinawa Island , Ryukyu Islands , 9 Nov. 2000. TAIWAN: BMNH 1979.3 .21.333, 109.8 mm SL, Tainan; KAUM–I. 113218, 77.7 mm SL, KAUM–I. 113219, 83.6 mm SL, KAUM–I. 113782, 90.5 mm SL, KAUM–I. 113784, 80.3 mm SL, off Dong-gang , Pingtung County, 10–50 m depth GoogleMaps .

Diagnosis. A species of Sardinella with the following combination of characters: caudal fin with black posterior margin; lateral body scales with centrally discontinuous vertical striae, and few perforations and pores posteriorly; 38–41 (modally 39) scale rows in longitudinal series; body scales deciduous; black spot on dorsal-fin origin; pelvic fin with one unbranched and seven branched rays; gill rakers 34–42 (39) in upper series on 1st gill arch, 64–72 (67) in lower series, 99–112 (103) in total; gill rakers 33–40 (35) in upper series on 2nd gill arch, 64–76 (74) in lower series, 97–115 (101) in total; gill rakers 31–38 (33) in upper series on 3rd gill arch, 48–60 (57) in lower series, 79–98 (84) in total; gill rakers 24–31 (27) in upper series on 4th gill arch, 37–47 (39) in lower, 62–77 (68) in total; gill rakers 25–31 (27) on hind face of third gill arch; 17 or 18 (18) + 12–14 (13) = 30–32 (31) scutes on ventral of body; pectoral fin long, 20.7–23.4% SL; pelvic fin long, 11.9–13.1% SL; upper jaw moderately long, 10.8–12.4% SL; lower jaw moderately long, 11.8–13.4% SL; pre-anal-fin length 77.4–82.3% SL.

Description. Counts and measurements, expressed as percentages of SL, are given in Table 1 View TABLE 1 . Data for the holotype are presented first, followed by paratype data in parentheses. Body oblong, compressed, deepest at dorsal-fin origin. Dorsal profile of body elevated from snout tip to dorsal-fin origin, thereafter decreasing to uppermost point of caudal-fin base. Ventral profile of body curved downward from lower-jaw tip to pelvic-fin insertion, thereafter rounded to ventralmost point of caudal-fin base. Anus on ventral midline, slightly anterior to anal-fin origin, posterior to midpoint of body. Mouth terminal, small, posterior tip of maxilla not reaching vertical through anterior margin of iris. Premaxilla and hypomaxilla without teeth. Ventral margin of maxilla toothed. Lower jaw with several conical teeth anteriorly. Posterior ramus of lower jaw elevated. Second supramaxilla symmetrical. Nostrils close to each other, anterior to orbit. Orbit elliptical, eye and iris round. Eyes covered with adipose eyelid posteriorly. Interorbital space flat. ten (seven to 11) bony striae on top of head. Gill rakers long, slender, with small asperities on anterior surface. Pseudobranchial filaments present. Gill opening with two fleshy outgrowths on posterior margin, a large papilla on ventral margin. Posterior margins of preopercle and opercle smooth. Scales cycloid, thin, deciduous, except for robust ventral scutes. Scales on lateral body surface with several centrally discontinuous vertical striae, few perforations and pores posteriorly ( Fig. 2 View FIGURE 2 ). Bases of dorsal and anal fins with low scaly sheaths. Predorsal scales paired. No elongate, wing-like scales present beneath normal paired scales. No scales on head and fins, except for a broad triangular sheath of scales on caudal fin. Abdomen from isthmus to anus with 31 (30 to 32) scutes. Predorsal scutes absent. No lateral line. Anteriormost point of pectoral-fin insertion anterior to posteriormost point of opercle. Upper, posterior and ventral margins of pectoral fin nearly straight. Posterior tip of pectoral fin pointed. Pectoralfin axillary scale present. Posteriormost dorsal-fin ray not filamentous. Anteriormost point of pelvic-fin insertion located directly below base of 7th (7th–10th) dorsal-fin ray. Posterior tip of depressed pelvic fin reaching between vertical through posterior end of dorsal-fin base and anus. Pelvic-fin axillary scale present. Anal-fin origin posterior to vertical through posteriormost point of dorsal-fin base. Two posteriormost anal-fin rays enlarged. Caudal fin forked. Posterior tips of caudal-fin lobes pointed.

Coloration when fresh. [Based on color photographs of seven specimens (KAUM–I. 113219, 108333, 108334, 108335, 108336, and SPMN-PI 44303, 44304)]. Dorsum bluish-green (or bluish-black). Lateral surface of body yellowish-silver, upper part metallic blueish. Black spot on dorsal-fin origin. Dorsal fin yellow, melanophores scattered on upper part of fin. Pectoral, pelvic, and anal fins yellowish (or translucent whitish). Caudal fin yellowish, posterior margin black. Black melanophores scattered on caudal-fin rays.

Color of preserved specimens. Body dark brown dorsally, elsewhere yellowish-silver. Black spot on dorsal-fin origin and distal tips of caudal fin lobes. Melanophores scattered on upper part of dorsal fin.

Distribution. Currently known only from Okinawa Island, Ryukyu Islands, Japan and southwestern Taiwan. The species inhabits coastal shallow waters and estuaries.

Etymology. The specific name alcyone is derived from Greek meaning “kingfisher”, in reference to the brilliant blueish dorsum of the species.

Remarks. Sardinella alcyone is assignable to the genus Sardinella , defined by Whitehead (1985) and Munroe et al. (1999), due to its compressed body, abdomen covered with prominently keeled scutes, paired predorsal scales, a symmetrical second supramaxilla, toothless hypomaxilla, two enlarged posteriormost anal-fin rays, the dorsal fin without filamentous rays, and two fleshy outgrowths on the hind margin of the gill opening. The new species most closely resembles Sardinella pacifica , sharing centrally discontinuous striae on the lateral body scales, a dark spot on the dorsal-fin origin, more than 63 lower gill rakers on the first gill arch, 8 pelvic-fin rays, 17 or 18 prepelvic scutes, and more than 13 pseudobranchial filaments ( Whitehead 1985; Munroe et al. 1999; Stern et al. 2016; Hata & Motomura 2019a, b). However, S. alcyone is distinguished from the latter by the number of gill-rakers on the first to fourth gill arches ( Table 1 View TABLE 1 ; Fig. 3 View FIGURE 3 ), and greater pectoral fin (20.7–23.4% SL vs. 18.2–20.8% in S. pacifica ; Fig. 4A View FIGURE 4 ), pelvic fin (11.9–13.1% SL vs. 10.3–11.9%; Fig. 4B View FIGURE 4 ), maxilla (10.8–12.4% SL vs. 9.3–10.9%; Fig. 4C View FIGURE 4 ), lower jaw (11.8–13.4% SL vs. 10.4–11.6%; Fig. 4D View FIGURE 4 ) and pre-anal-fin length (77.4–82.3% SL vs. 72.9–79.3%; Fig. 4E View FIGURE 4 ) proportions ( Hata & Motomura 2019b; this study).

TABLE 1. Counts and measurements of specimens of Sardinella alcyone n. sp.

  Holotype Paratypes  
  Japan Japan and Taiwan  
  KAUM–I. 108333 n = 18  
Standard length (SL; mm) 96.1 66.6–109.8  
Counts     Modes
Dorsal-fin rays (unbranched) 4 4–5 4
Dorsal-fin rays (branched) 15 14–16 15
Anal-fin rays (unbranched) 3 3–4 3
Anal-fin rays (branched) 18 16–19 18
Pectoral-fin rays (unbranched) 1 1 1
Pectoral-fin rays (branched) 14 13–16 14
Pelvic-fin rays (unbranched) 1 1 1
Pelvic-fin rays (branched) 7 7 7
Gill rakers on 1st gill arch (upper) 39 34–42 39
Gill rakers on 1st gill arch (lower) 68 64–72 67
Gill rakers on 1st gill arch (total) 107 99–112 103
Gill rakers on 2nd gill arch (upper) 37 33–40 35
Gill rakers on 2nd gill arch (lower) 74 64–76 74
Gill rakers on 2nd gill arch (total) 111 97–115 101
Gill rakers on 3rd gill arch (upper) 35 31–38 33
Gill rakers on 3rd gill arch (lower) 57 48–60 57

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TABLE 1. (Continued)

  Holotype Paratypes  
  Japan Japan and Taiwan  
  KAUM–I. 108333 n = 18  
Gill rakers on 3rd gill arch (total) 92 79–98 84
Gill rakers on 4th gill arch (upper) 27 24–31 27
Gill rakers on 4th gill arch (lower) 40 37–47 39
Gill rakers on 4th gill arch (total) 67 62–77 68
Gill rakers on posterior face of 3rd gill arch 26 25–31 27
Prepelvic scutes 18 17–18 18
Postpelvic scutes 13 12–14 13
Total scutes 31 30–32 31
Scale rows in longitudinal series 38 38–41 39
Pseudobranchial filaments 18 16–20 17
Measurements (%SL)     Means
Head length 26.6 24.7–28.6 27.1
Body depth 34.3 26.4–36.8 31.1
Pre-dorsal-fin length 46.0 43.4–46.8 45.4
Snout tip to pectoral-fin insertion 27.1 26.5–29.1 27.7
Snout tip to pelvic-fin insertion 55.2 51.9–56.4 54.4
Pre-anal-fin length 81.6 77.4–82.3 80.3
Dorsal-fin base length 15.8 14.3–17.1 15.8
Anal-fin base length 15.0 14.9–18.4 16.4
Caudal-peduncle length 6.7 6.1–9.6 7.4
Caudal-peduncle depth 9.6 8.2–11.8 9.9
D–P1 34.1 32.6–34.9 32.7
D–P2 33.1 25.6–36.0 30.2
D–A 44.0 39.6–47.0 42.5
P1–P2 29.4 25.6–29.3 28.2
P2–A 30.4 27.5–30.9 28.7
Pectoral-fin length 21.9 20.7–23.4 21.8
Pelvic-fin length 12.1 11.9–13.1 12.4
Interorbital width 4.5 4.1–4.9 4.6
Postorbital length 11.8 11.2–12.4 11.8
Upper-jaw length 11.9 10.8–12.4 11.6
Mandible length 12.2 11.8–13.4 12.5
GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF