49: DERICHTHYIDAE (LONGNECK EELS)
forwards. Teeth small, in broad bands on jaws and vomer.
Gill openings nearly horizontal, under throat, but quite
separate. Lateral line and head pores obvious. No scales.
Uniform brown to black. Attains 40 cm.
Occurs in midwater of open ocean in depths greater than
500 m. No commercial significance. Two genera; 2 of the 3
valid species are found in our area.
KEY TO GENERA
la Snout blunt, rounded, jaws about equal; D origin well
behind P, about midway between snout and anus . . .. Derichthys
lb Snout narrow, its tip expanded, lower jaw much shorter
than upper; D origin just behind P tip ........ Nessorhamphus
Genus Derichthys Gill, 1884
Monotypic.
49.1 Derichthys serpentinus
Gill, 1884
Derichthys serpentinus Gill, 1884: 443 (North Atlantic); Goode &
Bean, 1896: 161 *; Castle, 1970: 444. Grammatocephalus kempi Norman,
1930: 339, Fig. 34 (off Cape Town).
Head 7.5, depth 20. Snout overlapping lower jaw; a series of longitudinal striations behind eye; about 55 pores in LL before anus. Vertebrae
126-134.
Uniform black, LL pores light. Attains 40 cm. A single
specimen from west of Cape Town, in 850 - 950 m; occurs
worldwide.
49.1 Derichthys serpentinus: 22.5 em.
Genus Nessorhamphus Schmidt, 1930
Two species; N. danae Schmidt, 1931 (with 136-146 vertebrae and a dark, midventral streak from head to anus) is
known from the tropical Atlantic and Indian oceans.
49.2 Nessorhamphus ingolfianus
(Schmidt, 1912)
Leptocephalus ingolfianus Schmidt, 1912: 49, PI. 3, Fig. 8 (larva, North
Atlantic). Nessorhamphus ingolfianus: Schmidt, 1930: 371; 1931: 4*.
Head 7, depth 23. Anus at about midpoint of body. Snout and upper
jaw extended well forwards, the tip spatulate and expanded; vomerine
teeth in a broad patch in front of lower jaw with mouth closed. Vertebrae
150-159.
192
Dark brown. Attains 40 cm. Known in moderately deep
water off the Cape; also worldwide.
'.'
49.2 Nessorhamphus ingolfianus: 35 em.
Arrow eels
Family No. 50: CYEMIDAE
by P.H.J. Castle
Pylpalings
Body short, truncated, arrow-shaped, delicate. Pectoral
fins present. Dorsal fin origin over anus; median fins continuous around tail. Mouth extends well behind eye; jaws
elongated. Teeth small to very minute, in many rows, forming rasp-like, tooth-bearing surfaces on jaws and vomer.
Gill openings lateral, below pectoral. Lateral line and head
pores when present are delicate tubes. No scales. Uniform
black or red.
Occurs in midwater from 800 to 5 000 m, the larvae nearer
the surface and very distinctive. No commercial significance. Two monotypic genera, both in our area.
KEY TO GENERA
1a Body black; C truncate; eye small; vertebrae 68-80 . . . . .. Cyema
1b Body red; C pointed; eye greatly reduced;
vertebrae 101-108 ......................... Neocyema
50.1 Cyema atrum
Gunther, 1878
Cyema atrum Gunther, 1878: 251 (southern Indian Ocean and East
Pacific); 1887: 265*; Bertin, 1937: 25.
Body distinctively short and arrow-shaped, with a squarish tail and
much elongated jaws. Vertebrae 68-80.
Body black. Attains 60 cm. A distinctive midwater
species known from deep-water off our southwest coast;
occurs worldwide.
50.1 Cyema atrum: 11 em.
forwards. Teeth small, in broad bands on jaws and vomer.
Gill openings nearly horizontal, under throat, but quite
separate. Lateral line and head pores obvious. No scales.
Uniform brown to black. Attains 40 cm.
Occurs in midwater of open ocean in depths greater than
500 m. No commercial significance. Two genera; 2 of the 3
valid species are found in our area.
KEY TO GENERA
la Snout blunt, rounded, jaws about equal; D origin well
behind P, about midway between snout and anus . . .. Derichthys
lb Snout narrow, its tip expanded, lower jaw much shorter
than upper; D origin just behind P tip ........ Nessorhamphus
Genus Derichthys Gill, 1884
Monotypic.
49.1 Derichthys serpentinus
Gill, 1884
Derichthys serpentinus Gill, 1884: 443 (North Atlantic); Goode &
Bean, 1896: 161 *; Castle, 1970: 444. Grammatocephalus kempi Norman,
1930: 339, Fig. 34 (off Cape Town).
Head 7.5, depth 20. Snout overlapping lower jaw; a series of longitudinal striations behind eye; about 55 pores in LL before anus. Vertebrae
126-134.
Uniform black, LL pores light. Attains 40 cm. A single
specimen from west of Cape Town, in 850 - 950 m; occurs
worldwide.
49.1 Derichthys serpentinus: 22.5 em.
Genus Nessorhamphus Schmidt, 1930
Two species; N. danae Schmidt, 1931 (with 136-146 vertebrae and a dark, midventral streak from head to anus) is
known from the tropical Atlantic and Indian oceans.
49.2 Nessorhamphus ingolfianus
(Schmidt, 1912)
Leptocephalus ingolfianus Schmidt, 1912: 49, PI. 3, Fig. 8 (larva, North
Atlantic). Nessorhamphus ingolfianus: Schmidt, 1930: 371; 1931: 4*.
Head 7, depth 23. Anus at about midpoint of body. Snout and upper
jaw extended well forwards, the tip spatulate and expanded; vomerine
teeth in a broad patch in front of lower jaw with mouth closed. Vertebrae
150-159.
192
Dark brown. Attains 40 cm. Known in moderately deep
water off the Cape; also worldwide.
'.'
49.2 Nessorhamphus ingolfianus: 35 em.
Arrow eels
Family No. 50: CYEMIDAE
by P.H.J. Castle
Pylpalings
Body short, truncated, arrow-shaped, delicate. Pectoral
fins present. Dorsal fin origin over anus; median fins continuous around tail. Mouth extends well behind eye; jaws
elongated. Teeth small to very minute, in many rows, forming rasp-like, tooth-bearing surfaces on jaws and vomer.
Gill openings lateral, below pectoral. Lateral line and head
pores when present are delicate tubes. No scales. Uniform
black or red.
Occurs in midwater from 800 to 5 000 m, the larvae nearer
the surface and very distinctive. No commercial significance. Two monotypic genera, both in our area.
KEY TO GENERA
1a Body black; C truncate; eye small; vertebrae 68-80 . . . . .. Cyema
1b Body red; C pointed; eye greatly reduced;
vertebrae 101-108 ......................... Neocyema
50.1 Cyema atrum
Gunther, 1878
Cyema atrum Gunther, 1878: 251 (southern Indian Ocean and East
Pacific); 1887: 265*; Bertin, 1937: 25.
Body distinctively short and arrow-shaped, with a squarish tail and
much elongated jaws. Vertebrae 68-80.
Body black. Attains 60 cm. A distinctive midwater
species known from deep-water off our southwest coast;
occurs worldwide.
50.1 Cyema atrum: 11 em.