Trachinotus macrospilus, Smith-Vaniz & Walsh, 2019

Smith-Vaniz, William F. & Walsh, Stephen J., 2019, Indo-West Pacific species of Trachinotus with spots on their sides as adults, with description of a new species endemic to the Marquesas Islands (Teleostei: Carangidae), Zootaxa 4651 (1), pp. 1-37 : 5-9

Trachinotus macrospilus new species

Marquesas dart

Figures 1 , 3 , 4 , 5 A-8, 11; Tables 1–8

Trachinotus oblongus (not of Cuvier) Kendall & Goldsborough, 1911:272, pl. 1 (description; Nukuhiva); Fowler, 1938:279 (listed; Nuka Hiva).

Trachinotus bailloni (not of Lacépede) Weber and de Beaufort, 1931:288 (in part, distribution included Marquesas); Bagnis et al., 1972:47, unnumbered color photo (misidentification, in part, upper photo).

Trachinotus sp. Randall, 1985:472 (listed; Marquesas); Randall and Earle, 2000:13 (listed; Marquesas); Delrien-Trottin et al., 2015, unpaginated (listed as Marquesas endemic species).

Holotype. USNM 409238, 292 mm FL, Marquesas Islands, Hatuta’a, North Rock, 7°53’47”S, 140°33’43”W, 0- 10 m, rotenone, MARQ-238, S. Planes, E. Delrieu-Trottin, P. Sasal, J. Mourier, M. Veuille, R. Galzin, T. Lison de Loma , G. Mou-Tham and J.T. Williams, 31 Oct. 2011.

Paratypes. 28 specimens, 22–339 mm FL, all from the Marquesas Islands : USNM 409237 (1, 292) , USNM 409239 (1, 303) , USNM 409240 (1, 298), and USNM 409241 (1, 324), all taken with the holotype ; ANSP 153724 (1, 141 C&S; 2, 167–191) and BPBM 10441 (2, 174–175), Nuka Hiva , Taiohas Bay, bait seine, D.W. Strasburg, 6 Sep. 1957 ; CAS 29872 (1, 22), Nuka Hiva , Taiohas Bay, night lights of Yacht “Zaca,” Templeton Crocker Expedition, 6–15 Oct. 1934 ; USNM 409236 (1, 339), Hatuta’a , North Rock, J.T. Williams et al., 6 Jul. 2012 ; USNM 409385 (1, 142) and USNM 409386 (1, 65), Tahuata , on W side of island in Baie Anaeta, 0–3 m, J.T. Williams et al., 6 Nov. 2011 ; BPBM 10470 (2, 135–152), Via Taha , bait net, “ Charles H. Gilbert,” cruise 54, J. Magnuson, 18 Oct. 1961 ; BPBM 12473 (1, 275), Nuku Hiva, W. side Santineaae de l’ouest, 3 m, D.B. Cannoy, 10 May 1971 ; BPBM 27776 (2, 191–206), Taiohae Bay , beach seine, “ Hugh M. Smith,” cruise 31, J.E. King, 25 Nov. 1955 ; BPBM 12408 (1, 296), Ua Huka , 4 mi., NE of Motu Takatai, near shore, 8 ft. spear, J.E. Randall, 6 May 1997 ; MCZ 29732 (1, 194) , MCZ 29733 (1, 169) and MCZ 29734 (1, 209), Nuka Hiva , received from U.S. Bureau of Fisheries, via A. Agassiz, 4 Aug. 1910 ; UF 133588 (1, 192), Ua Pou, NW corner, 2 m, speared, L. Rocha, 18 Aug. 2003 ; USNM 412504 (1, 248), Ua Pou , 9°28’S, 140°03’07”W, 2–30 m, J.T. Williams et al., 5 Nov. 2011 ; USNM 66065 (3, 209–245) and USNM 66066 (1, 201), Nuka Hiva, “Albatross,” 1899-1900 .

Diagnosis. A species of Trachinotus in which adults have only 1 or 2 large black spots on their sides; the largest spot larger than iris diameter (usually smaller than iris diameter in T. baillonii and equal to or larger than eye diameter in T. botla and T. coppingeri ), and in having no large spot positioned above the pectoral fin (adults of T. botla and T. coppingeri have 1 or 2 large spots above the pectoral fin). Height of largest spot plotted against head length is also larger than in T. baillonii ( Fig. 6 ). Heights of dorsal- and anal-fin lobes of adults are also usually shorter than in the other three species ( Fig. 7 ). Dorsal fin VI-I, 23–26; anal-fin II-I, 23–25; vomerine tooth patch usually chevron shaped and palatine tooth patch relatively long ( Fig. 2B ).

Description. Counts and measurements of the holotype are given first followed in parentheses by those of the paratypes. Body depth 2.8 (2.2–2.7) in FL; head length 4.5 (4.0–4.7) in FL; convex dorsal profile; dorsal fin VI-I, 24 (23–26), spines short becoming partially embedded in large individuals; anal fin II-I, 24 (23–24); pectoral fin 16 (15–16); vertebrae (precaudal + caudal) 10 + 14; anal-fin pterygiophores inserted in first interhaemal space 3 ( Fig. 1 ); dorsal- and anal-fin lobes relatively short and subequal in length ( Fig. 7 ); anal-fin base only slightly longer than dorsal-fin base; caudal fin deeply forked with long pointed lobes; pectoral fin 1.3 (1.2–1.8) in HL, pelvic fin 2.7 (2.2–3.4) in HL; pectoral/pelvic fin ratio 2.1 (1.6–2.5); lateral line slightly curved over pectoral fin, then straight to base of caudal fin, no scutes; developed gill rakers: upper 9 (6–11), lower 15 (14–17), total 24 (21–27); upper jaw extends slightly beyond anterior margin of iris; head bluntly pointed; cheek scaled; jaws with narrow band of villiform teeth; tongue without teeth; vomerine tooth patch usually chevron shaped and palatine tooth patch relatively long ( Fig. 2B , Table 2 ). Selected mensural data mostly for specimens> 200 mm FL are given in Tables 7–8 and selected measurements are plotted in Figs. 6–8 .

Color when fresh ( Figs. 4 , 5A ). Head and body mostly silvery, bluish above becoming white below; sides with 1 or 2 large black spots with well-defined margins and occasionally a very small faint spot, the largest spot larger than iris diameter but smaller than eye diameter; all large spots extend about 1/3 their diameter below lateral line and none above the pectoral fin, largest spot ranges from a vertical well in front of to slightly behind second dorsal- fin origin. Pelvic fin white and lobes of dorsal, anal, and caudal fins dusky (outer margins very dark in 142 mm FL specimen ( Fig. 4C .).

Color in alcohol similar to life colors except head and body uniformly pale except for black spots.

Comparisons. The new species is most closely related to the allopatric T. baillonii but differs in having a larger spot on the side ( Fig. 6 ), which is larger than iris diameter (vs. approximately equal to or smaller than iris diameter in T. baillonii ). Height of the dorsal- and anal-fin lobes are usually shorter than in the other three species ( Fig. 7 ). Adults of T. botla and T. coppingeri also differ in having the largest spot on the side approximately equal to eye diameter and oval-shaped or vertically elongate (especially in large specimens), and 1 or 2 large spots above the pectoral fin (vs. no large spot present in T. macrospilus ).

Size. Largest examined specimen 34 cm FL and 42 cm TL.

Ecology. Adults have only been collected from the surf zone.

Distribution. ( Fig. 11 ) Endemic to the Marquesas Islands.

Remarks. With a reported shore fish fauna of 495 species and 13.7% endemism ( Delrien-Trottin et al., 2015), the Marquesas Islands have the third greatest species-level endemism for insular coral reef fishes in the Indo-Pacific. Easter Island, with a much smaller total fauna of only 169 marine fish species and a similar geographic size, has a 21.7% rate of endemism ( Randall and Cea, 2011), exceeded only by Hawaii with about 25% endemism of its marine ichthyofauna ( Randall, 2007). The Marquesas Islands are high islands of recent volcanic origin and, as discussed by Randall and Earle (2000), combined with their isolation both geographically and hydrographically (westernly South Equatorial Current and major upwelling events) has led to the high level of endemism of the ichthyofauna.

Etymology. From the Greek makros (long, large) and spilos (spot), in reference to the relative height of the largest and usually single spot on the mid-side of the body of adults.

Figures

FIGURE 1. Anterior part of anal fin of Trachinotus macrospilus (ANSP 153724) with 3 pterygiophores in first interhemal space. Abbreviations: As, anal-fin spines; Apt1, first anal-fin pterygiophore; Hs, haemal spines; IHS1, first interhaemal space. Photograph by Zachary S. Randall.

TABLE 2. Frequency distribution of vomerine and palatine dentition types A or B (see Fig. 2) in selected Indo-West Pacific Trachinotus species

FIGURE 3. Trachinotus macrospilus, MCZ 29732, 211 mm FL, Marquesas Islands. After Kendall and Goldsborough, 1911, plate 1, as “Trachinotus oblongus.”

FIGURE 4. Trachinotus macrospilus, all from the Marquesas Islands: A, USNM 409238, 292 mm FL, holotype (left side); B, USNM 409238, holotype (right side reversed); C, USNM 409385, 142 mm FL. Photographs by Jeffrey T. Williams.

FIGURE 5. Trachinotus juveniles: A, T. macrospilus, USNM 409386, 65 mm SL, Marquesas Island; B, T. baillonii, ANSP 134305, in preservative, 87 mm FL, Cocos-Keeling Island; C, T. botla, ANSP 54830, in preservative, 74 mm FL, Pakistan. Photographs by Jeffrey T. Williams (A) and Zachary Randall (B, C).

FIGURE 6. Height of largest spot on mid-side of body plotted against head length in four species of Trachinotus.

FIGURE 7. Heights of dorsal- and anal-fin lobes plotted against fork length in two species of Trachinotus.

FIGURE 11. Distributions of Trachinotus macrospilus and T. baillonii. Solid symbols indicate specimens examined; open symbols indicate acceptable literature or photographic records.