Chiasmodontidae: L II A8

Chiasmodon niger Johnson, 1863.

Swallower

 

Egg diameter in µm

Number of oil globules

Diameter of oil globule in µm

Yolk texture

Perivitelline space

Position of oil globule at hatch

Gut length   at eye- pigment stage

Myomeres

1150-1345

1

310-340

clear

narrow

stern

19% of NL

ca. 42

 

Egg: The size, and large clear oil globule make this egg stant out when present, which is just as well, as it is rare. The yolk is rough-surfaced, but clear, and the oil globule is clear. There are 5-6 big splashy black pigment patches on the embryo and oil globule (B), those in the tail usually forming a continuous band. Incubation is 50-60hours (22-23°C).

Larva: In the early larva, the black pigment is arranged in 6 distinct patches, from in front of the eyes to the notochord tip (C). At 5 days the same arrangement was retained (D). C: 1 day, D: 5 days (22-23°C).

This egg was not successfully reared, but egg numbers were low. Four hatched larvae have been sequenced, and they match Chiasmodon niger, based on an adult sequence in BOLD. Judging from illustrations (Hardy 2006), this is correct. A similar larva collected in my plankton net off Park Rynie, in August 2007, and submitted as C. niger (DSLAF495-08) has however, barcoded as another species, though it is closely associated with LIIA8 in my dendrogram. An image of this larva is shown alongside image D above.

 

Linked samples Offshore Inshore
Eggs 21 3
Hits 13 3

This egg was uncommon off Park Rynie, having been seen on only 17 occasions, all in winter, except for a single December egg (blue graph). The egg was not seen in the DHM samples. The Park Rynie linked samples yielded many more eggs in the offshore samples (88%), which is to be expected for this deep-water species. The adults are mostly found at depths exceeding 750m (Johnson and Keene 1986). See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples