Cypselurus simus (Valenciennes, 1847)

Synonymy and bibliography.

Exocoetus simus Valenciennes in Cuvier & Valenciennes, 1847: 105–106 (original description; Hawaii). Günther 1866: 296 (listed as a probable synonym of Exocoetus brachysoma). Günther 1889: 37–38 (description; Honolulu). Günther 1910: 369 (short description; Hawaii). Bruun 1937: 182–183 (description of type). Collette et al. 1997: 13 (description of type).

Cypselurus simus . Jenkins 1903: 435–436 (description; Hawaii; in part). Fowler 1919: 15 (listed; Honolulu, Hawaii). Fowler & Ball 1925: 9 (Hawaii, Johnston Is.). Fowler 1928: 85 (short description; Central Pacific; in part). Tinker 1944: 100 (Hawaii). Woods & Schultz 1953: 184–186 (morphometry; Hawaii). Gosline 1955: 449 (listed; Johnston I.). Parin 1960a: 222, 253–254, 279 (description (after Bruun 1937, Fowler 1928); Central Pacific; in part). Parin 1960b: 156 (distribution; in part: Central Pacific). Gosline & Brock 1960: 131–132 (short description; Hawaii). Parin 1961a: 52–53, fig. 5 (description; Hawaii). Parin 1961b: 118, 129, 166 (morphology, systematics). Parin 1967: 52, 54 (distribution). Bagnis et al. 1973: 327–328 (Polynesia). Kovalevskaya 1980: 224 (listed). Gillett & Ianelli 1993: 178 (listed; Pacific Islands). Parin 1996: 302, 306 [359, 363] (distribution; Central Pacific). Parin 1999: 2165, 2175 (distribution, diagnostic characters, figure; Central Pacific). Mundy 2005: 287 (listed; Hawaii). Randall et al. 2005: 45 (listed; Easter I.). Shakhovskoy & Shtaut 2008: 404–408 [391–396], figs. 1–2 (early life history stages; Oahu, Kaneohe Bay (Hawaii)). Shakhovskoy & Parin 2010: 581–602 [559–579], figs. 1, 3, 5, 6c, 10 (description, osteology, morphometry, distribution; Central Pacific). Shakhovskoy 2018: 56–59, 64–67, 78, figs. 14–15, 18, S4 (distribution according to oceanographic factors).

Cypsilurus simus . Jordan & Evermann 1905: 134–135, fig. 46 (description; Hawaii; in part). Jordan & Seale 1906: 211 (listed; Hawaii). Fowler 1949: 59 (listed; Oceania; in part).

Cypsilurus poecilopterus (non Valenciennes). Jordan & Seale 1906: 210 (short description, figure; Oceania; in part). Schultz 1943: 57 (listed (USNM 52358); Pago-Pago, Samoa).

? Exocoetus ogilbyi (non Jordan & Snyder). Günther 1910: 371 (New Hebrides).

? Cypselurus spilopterus (non Valenciennes). Fowler 1928: 83 (short description; Central Pacific; in part?).

Cypselurus poecilopterus (non Valenciennes). Fowler 1928: 83 (in part: Johnston I.). Woods & Schultz 1953: 184–185, 187 (morphometry; in part: Samoa). Gosline 1955: 449 (listed (after Fowler & Ball 1925); Johnston I.). Gillett & Ianelli 1991: 3 (listed; in part: Tahiti, Cook I.). Mundy 2005: 287 (listed; Hawaii). Siu et al. 2017: 257 (listed; French Polynesia).

Cypselurus pitcairnensis (non Nichols & Breder). Parin 1961a: 54–56, fig. 6 (description; Easter I.). Parin 1961b: 112, 129, 166, fig. 8i (morphology, systematics).

? Cypselurus sp.1 . Miller et al. 1979: 38–39, fig. 44 (larvae; Hawaii).

Cheilopogon simus . Randall et al. 2004: 9 (listed; Tonga). Siu et al. 2017: 257 (listed; French Polynesia).

Probable misidentifications. Fowler (1932a: 276–277) described C. simus from Hong Kong and Seale (1935: 348) described a specimen 354 mm long from Bellona I.; however, judging by characters provided, both authors probably dealt with Cheilopogon unicolor (Valenciennes) . Herre (1953) erroneously listed C. simus as occurring in the waters of Philippines and Gomez et al. (2019: 550) reported that small numbers of C. simus are captured by the fisheries in Surigao del Norte, Philippines; both are misidentifications.

Holotype. The holotype (MNHN B-0836) of this species was described by Bruun (1937: 182–183) and Collette et al. (1997: 13).

Description. For the species description see Shakhovskoy & Parin 2010.

Comparative remarks. Cypselurus simus differs most strikingly from other species of the genus (except C. poecilopterus and C. callopterus, differences from which are given in our previous work, see Shakhovskoy & Parin 2010) in the spotted pigmentation of the pectoral fins. However, some representatives of this species have single spots on pectoral fins or are entirely devoid of spots, and such specimens are hard to distinguish from C. angusticeps Nichols & Breder. However, C. angusticeps differs in having fewer vertebrae (39–42 vs. 42–45 in C. simus), predorsal (usually <29 vs. usually> 29) and transverse (usually ≤ 8½ vs. usually> 8½) scales, and in other features ( C. angusticeps will be described in detail in the third part of this review). Several species of the genus Cheilopogon ( Ch. spilopterus, Ch. suttoni, Ch. atrisignis, Ch. pitcairnensis, Ch. rapanouiensis) may be confused with C. simus because they also have spots on the pectoral fins. However, these species may be distinguished by an elongated lower jaw that usually projects ahead of the upper jaw (which is usually pointed anteriorly vs. usually roundish in C. simus) and by the absence of true tricuspid teeth in the jaws (but some specimens of C. simus are also without tricuspid teeth). Juveniles of these species (except for Ch. pitcairnensis, whose juveniles are not described) differ in having a pair of chin barbels.