Sternoptyx diaphana Hermann 1781

Lima, Adriano T., Costa, Paulo A. S., Braga, Adriana C., Nunan, Gustavo W. A. & Mincarone, Michael M., 2011, Fishes of the family Sternoptychidae (Stomiiformes) collected on the Brazilian continental slope between 11 ° and 23 ° S, Zootaxa 2742, pp. 34-48 : 42

Sternoptyx diaphana Hermann 1781

( Fig. 2 F; Table 3)

Material examined. 32 specimens (15.7–49.1 mm SL): MNRJ 30124, 3(21.6–34.0 mm), D-0382; MNRJ 30129, 1(30.4 mm), D-0502; MNRJ 30130, 1(27.1 mm), D-0503; MNRJ 30133, 9(26.1–39.2 mm), D-0505; MNRJ 30134, 2(16.7–49.1 mm), D-0504; MNRJ 30138, 2(38.8–44.6 mm), E-0501; MNRJ 30143, 1(30.3 mm), E-0509; MNRJ uncat., 1(27.6 mm), E-0519; MNRJ 30149, 1(25.8 mm), E-0522; MNRJ 30156, 1(25.1 mm), E-0535; MNRJ 30158, 1(18.5 mm), E-0537; MNRJ 30161, 1(25.3 mm), E-0538; MNRJ 30164, 1(28.2 mm), E-0548; MNRJ 30166, 1(27.0 mm), E-0552; MNRJ 30352, 1(15.7 mm), AG2-9; MNRJ 30355, 2(19.5– 37.0 mm), AG2-1; MNRJ 30361, 1(20.8 mm), AG1-1; MNRJ 30367, 1(29.6 mm), AG2-3; MNRJ 30369, 1(23.5 mm), AG1-4.

Additional material. 5 specimens (20.3–27.8 mm SL): MZUSP 78245, 4(20.3–23.8 mm), REVIZEE Program, mid-water trawl, 31°04’25’’S, 49°15’05’’W, 29.xi.1999; USU 0 1387, 1(27.8 mm); MD-55, 21°24’S, 39°56’W, 09.v.1987.

Diagnosis. Sternoptyx diaphana can be differentiated from its congeners by the following combination of characters: dorsal-fin rays 8–11, usually less than 11; vertebrae 27 or 29, rarely 28; pectoral fin without pigmentation; dorsal-fin base usually smaller than 90% of the dorsal-blade base width; body depth much greater than its length; SAN height greater than three times body height; SL smaller than 50 mm.

Meristic description. Fin rays: D 8–11; A 12–15; P 1 9–10; P2 5. Gill rakers: 7–8 (4–5+1+2–3). Photophores: BR 5; I 5; AB 10; PAN 3; AN 3; SC 4.

Distribution. Worldwide in tropical and subtropical waters. In Brazil, it occurs off northeast and southeast regions, between 14° and 22°S. Also collected from a single station off southern Brazil at 31°S ( Figueiredo et al. 2002).

S. diaphana S. pseudodiaphana S. pseudobscura Standard length SL (mm) 15.7–49.1 34.0–46.1 17.2–51.4 Measurements in % SL

Pre-dorsal length 64.4–74.1 67.8–70.7 65.2–80.3 Pre-anal length 54.4–73.1 63.3–66.4 58.7–73.5 Pre-pelvic length 53.5–70.4 61.3–65.2 55.7–71.2 Pre-pectoral length 30.2–42.9 39.2–40.9 31.1–46.4 Body depth 77.5–77.5 73.5–88.5 77.5–94.1 Caudal peduncle depth 10.7–47.6 11.6–11.7 10.3–13.2 Caudal peduncle length 21.3–35.7 — 12.8–26.2 Trunk depth 41.3–52.3 37.7–39.4 34.9–47.3 Trunk length 31.6–42.1 39.1–39.5 14.9–28.6 SAN height 10.7–16.9 14.9–16.1 15.6–22.9 SAN depth 31.9–41.9 25.2–26.5 32.7–38.4 Dorsal fin base 12.9–19.4 17.2–19.0 11.3–19.0 Anal fin base 48.0–58.4 50.8–58.9 43.9–56.3 Pectoral fin length 29.2–38.3 29.8–33.3 27.6–33.5 Head length 25.5–35.2 28.4–30.9 26.1–32.8

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Figures

FIGURE 2. Sternoptychids collected on Brazilian continental slope during the Thalassa and Astro Garoupa expeditions (asterisks indicate photo of fresh specimens): A. Argyripnus atlanticus; B. Maurolicus stehmanni *; C. Argyropelecus aculeatus *; D. Argyropelecus hemigymnus; E. Argyropelecus sladeni; F. Sternoptyx diaphana *; G. Sternoptyx pseudodiaphana; H. Sternoptyx pseudobscura; I. Polyipnus sp.