Etmopterus lucifer, Jordan & Snyder, 1902

Ebert, David A. & Van Hees, Kelley E., 2018, Etmopterus marshae sp. nov, a new lanternshark (Squaliformes: Etmopteridae) from the Philippine Islands, with a revised key to the Etmopterus lucifer clade, Zootaxa 4508 (2), pp. 197-210 : 207

Key to the Etmopterus lucifer clade of Lanternsharks

1a. Lateral flank marking anterior and posterior branches dissimilar in length........................................ 2.

1b. Lateral flank marking anterior and posterior branches nearly equal in length...................11. ( E. burgessi subclade).

2b. Lateral flank marking anterior branch noticeably longer than posterior branch in length.............3 ( E. lucifer subclade).

2a. Lateral flank marking anterior branch noticeably shorter than posterior branch in length............5 ( E. molleri subclade).

3a. Body slender; ventral snout surface between nostrils bare, without dermal denticles; central caudal marking length 6 %TL or more................................................. Etmopterus lailae (Central North Pacific: Hawaiian Islands)

3b. Body stout; ventral snout surface between nostrils uniformly covered with dermal denticles, and depending on the species may or may not have small bare patches; central caudal marking length less than 5.1 %TL............................... 4.

4a. Flank marking anterior branch nearly twice the length of the posterior branch; area between nostrils without small bare patches. Etmopterus lucifer ...........................................(Western North Pacific: Japan to Philippines)

4b. Flank marking anterior branch only slightly longer than posterior branch; area between nostrils with small bare patches..................... Etmopterus sculptus . (Southeast Atlantic and Southwest Indian Ocean: Namibia to southern Mozambique)

5a. Posterior branch of lateral flank marking extends past second dorsal fin free rear tip................................ 6.

5b. Posterior branch of lateral flank marking extends does not past second dorsal fin free rear tip......................... 8.

6a. Flanks with elaborate pattern of conspicuous rows of dark dots and dashes............................................................................ Etmopterus dislineatus . (Southwestern Pacific: off northern Queensland, Australia)

6b. Flanks without elaborate pattern of conspicuous rows of dark dots and dashes..................................... 7.

7a. Anterior (6.0–10.6%) and posterior (9.3–12.7%) flank branches relatively shorter................................................................................................. Etmopterus alphus . (Southwestern Indian Ocean)

7b. Anterior (8.0–11.5%) and posterior (11.0–15.4%) flank branches relatively longer............................................................................ Etmopterus molleri . (Western Pacific: eastern Australasia to New Zealand)

8a. Caudal fin lacks a band or spot.......................................................................... 9.

8a. Caudal fin with a band or spot......................................................................... 10.

9a. Upper teeth with 4 or 5 pairs of cusplets on each side; dermal denticles not arranged in rows....................................................................... Etmopterus decacuspidatus . (Western North Pacific: South China Sea)

9b. Upper teeth with less than 4 or 5 pairs of cusplets on each side; dermal denticles arranged in rows............................................................................................. Etmopterus bullisi . (Western Atlantic)

10a. Length of posterior flank marking 11.4–12.6% TL, flank marking base length 2.8–3.4% TL, and length of caudal base marking length from tip of anterior finger to tip of posterior finger 7.0–7.9% TL. Etmopterus brachyurus .............................................................................. (Western Pacific: Japan to Philippines, possibly Australia)

10b. Length of posterior flank marking 9.1–11.2% TL, flank marking base length 3.5–4.9% TL, and length of caudal base marking length from tip of anterior finger to tip of posterior finger 10.6–14.1% TL.............................................................................................. Etmopterus samadiae . (Western Pacific: Papua New Guinea)

11a. Caudal fin without dark band at fin tip.......................... Etmopterus burgessi . (Western North Pacific: Taiwan)

11b. Caudal fin with dark band at fin tip...................................................................... 12.

12a. Caudal peduncle without dark saddle; caudal fin without dark band across middle of upper lobe and at fin tip.......................................... Etmopterus pycnolepis . (Southeastern Pacific: Nazca and Sala y Gomez submarine ridges)

12b. Caudal peduncle with dark saddle; caudal fin with dark band across middle of upper lobe and at fin tip................ 13.

13a. Caudal fin ventral lobe and upper post-ventral margin mostly white to translucent............................................... Etmopterus evansi . (Eastern Indian Ocean: off northern Western Australia, Indonesia, and Papua New Guinea)

13b. Caudal fin ventral lobe and upper post-ventral margin mostly black................................................................................................ Etmopterus marshae n. sp. (Western North Pacific: Philippines)