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Larvae Information Summary for
Protomyctophum crockeri
| Main Ref: | Moser, H.G. and E.H. Ahlstrom 1996 | |||
Yolk-sac larvae
| max | min | mod | Ref. | |
| Length at birth (mm) | 3.8 | |||
| Preanal L. % TL | 52 | 35 |
| Place of development | planktonic | |||
| Larval area | Northeastern Pacific (California Current region); Northwestern Pacific (Japan) | |||
| Yolk-sac | Ref: | |||
| Yolk | Oil globules | |||
| Rows on tail | ||||
| Other melanophores on tail | ||||
Post larvae
| Striking feature | light organs | |||
| Striking shape lateral | normal (not striking) | dorsal | ||
| Striking feature | light organs | |||
| Shape of gut | elongated | |||
| Gas bladder early | late | pigmented | ||
| Spinal armature early | no spines | late | no spines | |
| Pigmentation early | ||||
| Rows on tail | no rows | |||
| Other melanophores on tail | no other melanophores | |||
| Melanophores on head + trunk | no melanophores on head or trunk | |||
| Pigmentation late | ||||
| Rows on tail | no rows | |||
| Other melanophores on tail | no other melanophores | |||
| Melanophores on head + trunk | no melanophores on head or trunk | |||
| Urostyle region early | unpigmented | late | unpigmented | |
| Pectorals | normal without melanophores | |||
| Pelvics | fin rays only without melanophores | |||
| Slender body; short gut; foregut somewhat conical; head relatively small in preflexion and flexion stages; pointed snout; moderately narrow elliptical eye, lacks ventral choroid tissue; pigment scanty, only laterally on gut and patch above gas bladder; Br2 photophores form at about 8.0 mm; PO series, Br3 and upper OP the first to form at transformation. Single spot over gut and lack of pigment elsewhere (flexion and postflexion larvae); distinguished from P. thompsoni by lack of postanal ventral melanophores in preflexion larvae and presence of only one spot over the gut in larger larvae. Pigmentation: Preflexion: by about 5.0 mm, 1 (large) on each side of midgut. Flexion-postflexion: the one at gut enlarges and is more anterior; by about 10.0 mm, patch above gas bladder. Sequence of fin development: caudal, pectorals, anal, pelvics, dorsal. | ||||
Meristic characters
| max | min | mod | Ref. | |
| Total number of vertebrae | 38 | 36 | 31442 |
| L 1st feeding | Ref. | Months of presence of larvae | ||||
| max | Jan | Feb | Mar | Apr | ||
| min | May | Jun | Jul | Aug | ||
| mod | Sep | Oct | Nov | Dec | ||
| Water parameters Metric characters |
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