Key to Genera and Some Species of Macrouridae in Taiwan

(number of species in Taiwan in parentheses after genus)

1a. Six branchiostegal rays....................................................... 2

1b. Seven branchiostegal rays..................................................... 4

2a. Spinous 1D ray smooth; a stout continuous suborbital ridge terminating posteriorly in a sharp point; V 7................................................ Coelorinchus (23 spp.)

2b. Spinous 1D ray serrated (sometimes weakly) along leading edge; suborbital ridge not continuous and not ending in a sharp point; V 7–14...................................... 3

3a. Gill-rakers absent on lateral side of first gill arch; V 7 or 8; anus in middle third of distance between V and A...................................... Mataeocephalus hyostomus

3b. Gill-rakers present on lateral side of first gill arch; V 7–14; anus usually immediately anterior to A................................................... Coryphaenoides (4 spp.)

4a. Abdomen and isthmus with patches of fine black striations with silvery underlayment (especially when fresh); small lens-like light organ on chest connected by black medioventral line to a second lens immediately before anus........................................... 5

4b. Abdomen and isthmus lacking areas of fine black striations; light organ, if present, not as above .. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .. 7

5a. Nasal bones forming three flat platelike horizontal processes; gular membrane with net- or mesh-like pattern; prolonged distal portion of outer pelvic fin ray with narrow membranous flange................................................ Spicomacrurus kuronumai

5b. Nasal bones not forming horizontal platelike processes; gular membrane with thin black transverse lines at right angle to median line; outer pelvic fin ray tapers evenly to distal tip.... 6

6a. First dorsal fin with weakly denticulate spinous ray; gill rakers on inner side of first arch with 12–16 rakers on lower limb; V 7–9, usually 8.................... Hymenogadus gracilis

6b. First dorsal fin spinous ray entirely smooth along leading edge; gill rakers on inner side of first arch with 15–22 rakers on lower limb; V 7–12................. Hymenocephalus (4 spp.)

7a. Anus and urogenital pore within broad black naked area, the periproct, the posterior border of which abuts origin of A and spans most of space between V and A.................... 8

7b. Periproct smaller, not occupying most of space between V and A; anus (and urogenital pore) either abuts A origin, or separated from A by several scales rows, sometimes closer to insertion of V than to origin of A................................................. 10

8a. Origin of V behind P origin; 2nd spinous ray of 1D smooth.......... Trachonurus (2 spp.)

8b. Origin of V below or anterior to P origin; spinous 1D ray serrated along leading edge..... 9

9a. Head greatly inflated, broad and deep; snout fully scaled; a series of enlarged scales along anterior section of 2D........................................... Cetonurus globiceps

9b. Head not inflated, moderately compressed; underside of snout naked; no series of enlarged scales along 2D......................................... Sphagemacrurus (2 spp.)

10a. Olfactory organ massive, its diameter almost equal to that of orbit.... Macrosmia phalacra

10b. Olfactory organ small to moderate, much less than orbit diameter................... 11

11a. Most of dorsal surface and entire ventral surface of snout naked.......... Kumba (3 spp.)

11b. Dorsal surface of snout fully scaled; ventral surface of snout variously naked.......... 12

12a. Low jaws bearing enlarged, widely space, fang-like teeth in 1 or 2 rows; spinous 1D ray smooth............................................. Malacocephalus nipponensis

12b. Lower jaw teeth normal in size, closely spaced, none fang-like, in 2 or more rows to broad band; spinous 1D ray smooth or serrated along leading edge........................ 13

13a. V with 6 rays, placed anterior to P base; anus closer to A origin than to V insertion............................................................... Pseudonezumia pusilla

13b. V with 7 or more rays, position variable from below 1D to under preopercle; anus removed from A origin, usually closer to V insertion..................................... 14

14a. Head broadly inflated, interorbital space about 40% of HL; orbit diameter less than 25% HL; suborbital deep, about 20% HL.......................... Pseudocetonurus cf. septifer

14b. Head not especially inflated, interorbital space less than 35% HL; orbit diameter usually more than 25% HL, suborbital less than 20% HL..................................... 15

15a. Terminal and lateral snout scutes present, the terminal scute paired; suborbital ridge marked by two rows of coarsely modified scales........................................ 16

15b. Terminal and lateral snout scutes generally not well developed, the terminal scute single, if present, not large; no coarsely modified scales along suborbital ridge................. 17

16a. Outer series of rakers on GR-I usually absent (sometimes with a few rudimentary spicules); V 7 or 8................................................ Mataeocephalus (2 spp.)

16b. Outer series of rakers on GR-I always present, although sometimes rudimentary; V 7 to 17.............................................................. Nezumia (5 spp.)

17a. Upper jaw extending to below posterior one-third or more of orbit; premaxillary tooth band extends posteriorly beyond maxillary process; inner series of gill rakers on GR-I 14–20 total; no scales on gular or branchiostegal membranes.................... Ventrifossa (9 spp.)

17b. Upper jaw extending posteriorly to below anterior half of orbit; premaxillary teeth band does not extend beyond maxillary process; gill rakers on inner series of first arch usually less than 14 total; some species with scales on gular or branchiostegal membranes.............. 18

18a. Color brown to blackish, no silvery pigmentation; fins uniformly blackish; teeth in broad bands....................................................... Kuronezumia dara

18b. Color pale to greyish; silvery pigmentation ventrally in fresh specimens; fins often with black blotches or streaks; teeth in relatively narrow bands........... Lucigadus nigromarginatus