Embryonic development of the brown catshark, Apristurus brunnus (Gilbert, 1892)

This slide was included in a presentation by Gilbert Van Dykhuizen at the 1992 AES meeting in Urbana-Champaign IL.
Abstract: " Egg cases were collected from the Monterey Submarine Canyon and transported to a deep sea holding facility at the Monterey Bay Aquarium. Yolk diameter, embryo length, gill and eye development were observed on an monthly or bimonthly schedule. Incubation period is approximately 24 months and hatchlings survived 30-50 days with no feeding observed despite attempts to feed them.

(If I (HFM) remember correctly, water temperature was between 8 and 10 degrees Celsius)

Incubation Interval (month) Embryo size (mm) Yolk size (mm) Branchial development Eye development Fin development Head development, Head width Pigmentation
35 mm, imbeddedoval    translucent
614-18 mmovalgill slits, heart beginningorbit developingdorsal/anal finsnaresopaque
919-25 mmovalext. filamentseye formed buccal cavityopaque
12, eggcase opens26-35 mmoval, ca. 20 mmfilaments 1-2 mmblack outer ring, pupil formedpect/pelvic fins, myotomesnares formed 
1536-45 mm19-18 mmfilaments 3-5 mmblack outer ring vascularizeddenticles on dorsal side and tailhead flattened, HW = 5-6 mm 
1846-55 mm17-16 mmfilaments being resorbed, 1.5 mmeye bulging, black and red ringfins almost distinctHW = 7-8 mmlight pink
2156-65 mm15-13 mmfilaments resorbedentire eye black, well developedfins developedHW = 9-10 mm, vascularizedbody pink, tail light brown
2466-75 mm12-6 mm, absorbing internallydevelopedeye green, developed HW = 11-12 mmhead and tail brown
27, ready to hatch76-85 mm5-1.5 mm, absorbed internallydevelopedeye green, developed HW = 13-15 mm 

Created 1992 by Gilbert Van Dykhuizen; revised Jan. 1996. For question please email gvan@wwdb.org

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Please send comments or corrections to henry@elasmollet.org