Atlas of Atlantic Ostracods
Taxon details
Macrocypridina castanea (Brady, 1897)
- Order:
- MYODOCOPIDA
- Family:
- Cypridinidae
- Size range (females):
- 4.7-7.6 mm
- Size range (males):
- 4.8-7.3 mm
- Depth:
- meso/bathypelagic
Notes
303 records
This large chocolate coloured myodocopid species occurs frequently, but seldom in abundance, at depths of 500-1000m. The juveniles, which are unpigmented, are often encountered at much shallower depths associated with the seasonal thermocline. Its colouration reduces its reflectivity to the blue-green light of most bioluminescence. But fresh specimens that have been dissected have been found to have luminescent stomach contents, so maybe the pigment also serves to mask the light from their stomachs. The chocolate pigment is concentrated in the outer layers of the carapace, but a clear window overlies the medial compound eyes. The eyes continually oscillate in living animals (Davenport, 1990). Their stomach contents suggest they are carnivores, but they have been collected as ‘swimmers’ in poisoned sediments traps deployed at depths of 1000m. The latitudinal range in the Atlantic is 60°N to 40°S, but it extends south to 50°S in the Pacific (Chavtur, 1977). However, such early records may have been confused this species with poulseni, which was once considered to be a subspecies. The latter is a somewhat shorter and has a more rounded posterior margin. The sizes listed below show that the separation of the early immature juvenile stages on the basis of size is not very satisfactory. The smallest juveniles correspond to the sizes of embryos normally retained with in the female’s carapace.
| All | n | Mean mm | s.d. | Range mm |
|---|---|---|---|---|
| Female | 195 | 6.40 | 0.248 | 5.92-7.33 |
| Male | 95 | 6.68 | 0.220 | 6.00-7.33 |
| A-1 | 101 | 4.16 | 0.238 | 3.76-4.64 |
| A-2 | 35 | 2.77 | 0.195 | 2.52-3.24 |
| A-3 | 5 | 2.32 | 0.080 | 2.24-2.44 |
| A-4 | 35 | 1.71 | 0.237 | 1.30-2.08 |
| A-5 | 26 | 1.08 | 0.036 | 1.02-1.16 |
| A-6 | 2 | 0.56-0.58 |
