Thrissina samam ( Montrouzier, 1857 )

Hata, Harutaka, Mandagi, Ixchel F. & Masengi, Kawilarang W. A., 2023, Resurrection of nominal species previously regarded as junior synonyms of Thrissina baelama (Fabricius, 1775) and their re-descriptions (Teleostei: Clupeiformes: Engraulidae), Raffles Bulletin of Zoology 71, pp. 279-302 : 290-293

Thrissina samam ( Montrouzier, 1857)

[English name: Samam Baelama Anchovy ] ( Figs. 1A–D , 9 ; Tables 6, 10)

Engraulis samam Montrouzier, 1857: 487 (original type locality: Woodlark Island, Louisiade Archipelago, Papua New Guinea; type locality: Garrer Bay , New Britain, Papua New Guinea based on neotype designated herein).

Engraulis macrops Kishinouye, 1911: 385 , pl. XXX, fig. 3 (type locality: Haha Island , Ogasawara Islands, Japan).

Engraulis baelama (not of Fabricius): Weber & de Beaufort, 1913 (in part): 33 (Lombok and Aru Islands, Indonesia).

Thrissocles baelama (not of Fabricius): Fowler, 1941 (in part): 683 [ Tawitawi Island ; Mareveles (currently Mariveles), Pagapas Bay , and Batangas, Luzon; Mindanao; Cebu; Gomomo Island ; Iloilo, Panay; Jolo Island ; Palawan; Cagayancillo; Mindoro; Leyte, Philippines; Danawan Island, Malaysia; Buru Island, Indonesia] .

Thryssa baelama (not of Fabricius): Whitehead et al., 1988 (in part): 425 (Ogasawara Islands and Philippines to Papua New Guinea); Wongratana et al., 1999 (in part): 1743 (Ogasawara Islands and Philippines to Papua New Guinea); Aonuma & Yagishita, 2013 (in part): 304, unnumbered fig. (Ogasawara Islands and Ryukyu Archipelago, Japan).

Thrissina baelama (not of Fabricius): Hata & Koeda, 2021: 11, fig. 1 (Okinawa Island, Ryukyu Archipelago, Japan); Hata et al., 2022b: 35 (Okinawa Island, Philippines, and Palau).

Neotype. BMNH 1971.2 .8.49, 79.6 mm SL, Garrer Bay , New Britain, Papua New Guinea (mouth of cove surrounded by coral reef and mangrove); 6 September 1970.

Other materials examined. 52 specimens, 40.3–104.1 mm SL: JAPAN: NSMT-P 2058 , 89.9 mm SL, Ogasawara Islands ; NSMT-P 19049 , 2 specimens, 56.1–58.4 mm SL, NSMT-P 19050 , 2 specimens, 64.7–65.6 mm SL, Nagura River , Ishigaki Island , Yaeyama Islands, Ryukyu Archipelago; ZUMT 11282 , 84.1 mm SL, ZUMT 11283 , 91.5 mm SL, Ryukyu Archipelago ; ZUMT 39727 , 40.3 mm SL, Okinawa Island , Okinawa Islands, Ryukyu Archipelago. PHILIPPINES: ZUMT 41003 , 69.8 mm SL, ZUMT 41004 , 58.9 mm SL, ZUMT 40900 , 2 of 8 specimens, 75.9–76.2 mm SL, Jolo Island . PALAU: NSMT-P 136575 , 52.3 mm SL, Urukthapel Island , 1 m depth; ZUMT ABE 3039 , 69.0 mm SL, ZUMT ABE 3040 , 2 specimens, 56.5–73.4 mm SL, ZUMT 62054 , 7 specimens, 84.1–104.1 mm SL, Palau. MALAYSIA: KAUM – I. 12499, 87.5 mm SL, off Tanjung Lipat , Kota Kinabalu, Sabah. INDONESIA: BPBM 19427 , 80.9 mm SL; Poka , northwest of Ambon Bay, Ambon. BPBM 36472 , 2 specimens. 81.8–84.8 mm SL, Laha , Ambon; NSMT-P 52718 , 79.5 mm SL, NSMT-P 56892 , 2 specimens, 91.5–98.8 mm SL, NSMT-P 136629 , 74.2 mm SL, SNMT-P 136644 , 3 of 5 specimens, 40.6–43.7 mm SL, NSMT-P 136649 , 1 of 7 specimens, 74.7 mm SL, NSMT-P 138469 , 93.0 mm SL, Kuta , Lombok; NSMT-P 61318 , 56.2 mm SL, Mawali , Lembeh Island; NSMT-P 63691 , 66.1 mm SL, NSMT-P 136645 , 88.2 mm, Ambon ; NSMT-P 145681 , 87.4 mm SL, NSMT-P 145682 , 76.8 mm SL, NSMT-P 145683 , 70.8 mm SL, NSMT-P 145684 , 72.9 mm SL, NSMT-P 145685 , 77.3 mm SL, NSMT-P 145686 , 91.7 mm SL, NSMT-P 145687 , 90.1 mm SL, NSMT-P 145688 , 86.8 mm SL, MZB 26553 , 78.1 mm, Tanahwangko , Sulawesi. PAPUA NEW GUINEA: BMNH 1971.2.8.50–58, 4 specimens, 69.9–75.9 mm SL, Garrer Bay , New Britain, Papua New Guinea (mouth of cove surrounded by coral reefs and mangroves)

Diagnosis. A species of Thrissina with the following combination of characters: short maxilla, 20.3–23.1% of SL; its posterior tip not reaching to posterior margin of opercle; first supramaxilla elongated, longer than half length of second; lower jaw rather long, 18.7–21.2% of SL; abdomen covered with 4–8 + 8–10 = 13–16 keeled scutes; no scutes anterior to pectoral fin; 1UGR 14–16, 1LGR 18–21, 1TGR 33–36; 2UGR 10–14, 2LGR 18–21, 2TGR 29–35; 3UGR 9–12, 3LGR 11–14, 3TGR 20–26; 4UGR 6–10, 4LGR 9–12, 4TGR 17–22; no distinct black blotches on dorsal fin; caudal peduncle rather narrow [9.0–10.6% (mean 9.7%) of SL] and long (9.7–11.0% of SL); pre-dorsal-fin length 47.7–53.1% of SL; pre-anal-fin rather short, 63.2–68.3% of SL; distance between pelvic-fin insertion and anal-fin origin rather short, 18.7–23.7% of SL; pectoral fin rather short, 16.9–19.1% of SL; pelvic fin rather short, 12.6–14.3% of SL; body rather elongated, 20.1–26.0% (mean 23.0%) of SL.

Colour of fresh specimens. Body uniformly silver. Dorsum black, upper lateral surface of body bluish-grey, with small densely scattered orange spots (also on upper lateral surface of head). Lateral surface of mid-part of snout transparent. Narrow non-pigmented ring-like band surrounding anterior part of snout. Branches of cephalic lateralis sensory canal on upper part of gill opening distinctly orange, forming an orange blotch above a faded black blotch. Fin rays of dorsal and caudal fins black. Dorsal and caudal fins, centrally reddish-orange, posteriorly margined black. Pectoral, pelvic, and anal fins whitish, semi-transparent. Iris and pupil bluishblack and silver, respectively.

Colour of preserved specimens. Body uniformly pale ivory. Dorsum dark brown. Melanophores densely scattered over entire body and head. Narrow non-pigmented ring-like band surrounding anterior part of snout. Melanophores scattered along fin rays of dorsal and caudal fins. Pectoral, pelvic, and anal fins without melanophores. No distinct black blotches on dorsal fin.

Distribution. Thrissina samam is distributed in the western Pacific from the Ogasawara Islands and Ryukyu Archipelago, Japan, to Palau and New Britain, Papua New Guinea ( Fig. 4 ).

Comparisons. Thrissina samam is characterised by the lowest gill raker numbers among the five species described herein [1TGR, 33–36 in T. samam (vs. 38 or more in T. evermanni , T. polynemoides , and T. tuberculosa ; 36–40 in T. baelama ); 2TGR, 29–35 in T. samam (vs. 36 or more in T. evermanni , T. polynemoides , and T. tuberculosa ; 33–38 in T. baelama ); 3TGR, 20–26 in T. samam (vs. 25 or more in T. evermanni , T. polynemoides , and T. tuberculosa ; 23–27 in T. baelama ); 4TGR, 17–22 in T. samam (vs. 20 or more in T. evermanni , T. polynemoides , and T. tuberculosa ; 18–22 in T. baelama ) ( Fig. 6 )]. The former further differs from T. baelama in having a narrower body [20.1–26.0% (mean 23.0%) of SL in T. samam vs. 23.0–26.9% (mean 24.5%; one of 26 specimens 21.2%) in T. baelama ], and caudal peduncle [9.0–10.6% (mean 9.7%) of SL vs. 10.1–11.5% (10.5%)], greater pre-dorsal-fin length [47.7–53.1% (mean 50.3%) of SL vs. 48.0–50.4% (mean 49.3%; never greater than 51%)], and longer caudal peduncle [9.7–11.0% (mean 10.1%) of SL vs. 8.7–9.7%, usually less than 10% (one specimen only 10.4%; mean 9.3%)] ( Fig. 7 ). Furthermore, T. samam is also distinguished from T. tuberculosa by lacking black blotches anteriorly on the dorsal fin (vs. several distinct black blotches present in T. tuberculosa ), and shorter pre-anal-fin length [63.2–68.3% (mean 65.9%) of SL in T. samam vs. 66.7–69.6% (68.2%) in T. tuberculosa ], pelvic-fin insertion to anal-fin origin distance [18.7–23.7% (mean 21.4%) of SL vs. 22.7–25.3% (23.6%)], pectoral-fin length [16.9–19.1% (mean 17.8%) of SL vs. 18.4–19.4% (18.9%)], pelvic-fin length [12.6–14.4% (mean 13.3%) of SL vs. 13.6–14.8% (14.3%)], maxilla length [20.3–23.1% of SL (mean 21.7%) vs. 22.5–23.7% (23.2%)], and lower-jaw length [18.7–21.2% (mean 19.9%) of SL vs. 20.1–21.4% (mean 20.7%)] ( Fig. 7 ).

Remarks. Engraulis samam was described by Montrouzier (1857) based on specimens collected from Woodlark Island, who reported that he had made a drawing of the specimen. However, both the type specimens and drawing have been lost ( Wongratana, 1980; Kottelat, 2013; Fricke et al., 2022; this study). The original description noted E. samam as having a triangular dorsal fin, the anal and caudal fins well separated, a serrated abdomen (a probable reference to the abdomen being entirely covered with ventral scutes), the dorsal body contour nearly straight, and the body elongate (depth approx. 18% of total length). These characters place the species in the genus Thrissina , as defined by Whitehead et al. (1988) and Wongratana et al. (1999) (as Thryssa ). To date, six species of Thrissina [viz., Thrissina brevicauda ( Roberts, 1978) , Thrissina hamiltonii (Gray, 1835) , Thrissina rastrosa ( Roberts, 1978) , T. samam , Thrissina scrachleyi (Ramsay & Ogilby, 1886) , Thrissina setirostris (Broussonet, 1782) ] have been recorded from New Guinea ( Whitehead et al., 1988; Wongratana et al., 1999). The original description of E. saman also noted “La direction du préopercule et de l’opercule est très-oblique. Pas de prolongement aux maxillaires [margins of preopercle and opercle oblique. Not extended to the maxilla]”, the latter character probably referring to the short maxilla, its posterior tip not reaching to the preopercle posterior margin. Because T. hamiltonii and T. setirostris both have a long maxilla, posteriorly well beyond the opercle posterior margin ( Whitehead et al., 1988; Wongratana et al., 1999; Hata et al., 2022a), they are considered specifically distinct from E. samam . Because Montrouzier (1857) also described E. samam as inhabiting coastal waters, T. rastrosa and T. scrachleyi , recorded only from middle and upper stretches of the Fly River ( Roberts, 1978), are also thought to be different species. Moreover, the length of Montrouzier’s (1857) E. samam (4 inches, approx. 10.2 cm total length) also differentiates that species from T. brevicauda , which attains only 56.5 mm SL ( Roberts, 1978). Finally, Montrouzier’s (1857) E. samam had a red spot above the gill slit, a colour feature found in T. samam specimens recognised herein.

Engraulis macrops was described by Kishinouye (1911) from specimens approx. 12 cm total length, collected from Haha Island, Ogasawara Islands, Japan in April 1907. Although the name was spelled as “ Engraulis macrops ” in the main account and the plate legend on p. 386, it was given as “ Engraulis macropus ” on pl. XXX, the latter simply being a spelling error ( Kottelat, 2013). This was upheld by Whitehead et al. (1988) and Fricke et al. (2022), although erroneously stated as “ micropus ”. Although the type specimens of E. macrops are apparently lost ( Kottelat, 2013; Fricke et al., 2022; this study), the meristic characters given in the original description generally matched those of T.

samam specimens examined in the present study. Moreover, an NSMT specimen collected from the Ogasawara Islands was found to be conspecific with T. samam . E. macrops is therefore considered to be a junior synonym of T. samam . A specimen collected from New Britain (BMNH 1971.2.8.49, 79.6 mm SL; Fig. 9 ) is herein designated as the neotype of Engraulis samam Montrouzier, 1857 , the collection locality becoming the type locality of the nominal species under Article 76.3 ( ICZN, 1999).

Figures

Fig. 1. A–D, Diagnostic characters of species previously identified as Thrissina baelama [A, lateral view of whole body, B, head (yellow line indicates posterior part of maxilla; blue line and broken lines indicate anterior and posterior margins of preopercle, respectively), C, first and second supramaxillae (left-right inverted), D, ventral view of isthmus (no scutes located anterior to pectoral fins)] and E, ventral view of isthmus of Thrissina encrasicholoides (scutes located anterior to pectoral fins) (A: fresh condition, 72.9 mm SL, Sulawesi, Indonesia; B–D: T. samam, NSMT-P 144842, 58.4 mm SL, Ryukyu Archipelago, Japan; E: T. encrasicholoides, NSMT-P 50306, 69.8 mm SL, Philippines) (B–E, alizarin stain).

Fig. 9. A, Neotype of Engraulis samam (BMNH 1971.2.8.49, 79.6 mm SL, New Britain, Papua New Guinea), and B, non-type specimen of Thrissina samam (fresh condition) (NSMT-P 145681, 87.4 mm SL, Sulawesi, Indonesia).

Fig. 4. Distributional records of Thrissina baelama (triangles), T. evermanni (squares), T. polynemoides (diamonds), T. samam (circles), and T. tuberculosa (star), based on specimens examined in this study.

Fig. 6. 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 Thrissina baelama (blue triangles ▲), T. evermanni (yellow squares ■), T. polynemoides (green diamonds ◆), T. samam (red circles ●), and T. tuberculosa (pink stars).

Fig. 7. Morphometrics of Thrissina baelama (blue triangles ▲), T. evermanni (yellow squares ■), T. polynemoides (green diamonds ◆), T. samam (red circles ●), and T. tuberculosa (pink stars) (all vs. standard length; SL). A, Ratio of caudal-peduncle depth to SL; B, pre-dorsal-fin length to SL; C, snout length to SL, D, body depth to SL; E, pre-anal-fin length to SL; F, dorsal-fin base length to SL; G, distance from pelvic-fin insertion to anal-fin origin to SL; H, pectoral-fin length to SL; I, pelvic-fin length to SL; J, maxilla length to SL; K, lower-jaw length to SL; L, caudal-peduncle length to SL.