Atlas of Atlantic Ostracods

Taxon details

Gigantocypris muelleri Skogsberg, 1920

Order:
MYODOCOPIDA
Family:
Cypridinidae
Size range (females):
14-20 mm
Size range (males):
12-16 mm
Depth:
bathypelagic

Notes

284 records

This large deep mesopelagic-bathypelagic myodocopid is reported to have a very widespread distribution in the Atlantic, but there are few records from other oceans. Poulsen (1962) recorded five Gigantocypris species, but only G. dracontovalis, a small abyssopelagic species has also been reported from the Atlantic. However, Discovery material from the Atlantic includes a few very large specimens about 30mm in length, a size consistent with G. agassizi. Skogsberg’s original description is of Southern Ocean material and hence this is likely to be the type form. Tibbs (1965) reported that G. muelleri has an extensive range in the Southern Ocean based on EltaninHowever, he but did not publish any positional data nor have we been able to locate any records of Tibbs' data. It seems extraordinary that such a large and conspicuous species has been so poorly reported. The Southern Ocean forms are appreciably larger then Atlantic specimens, so it has to be left open whether the Atlantic specimens are indeed G, muelleri. Its reported range is 64°S to 63°N. But, it tends to be more abundant at higher latitudes. It bathymetric range in the North Atlantic is 600-1500m, but there is some evidence for ontogenetic movements, since the shallower records are mainly juveniles and the deeper are adults. The live coloration of adults is predominantly orange-red, with the reflective naupliar eyes appearing silvery. The very large specimens that are probably a different, if not new species, were colourless. Specimens are very watery and are seldom collected undamaged. The species maintain neutral buoyancy by reducing the sulphate content of their haemolymph, and this is probably the functional reason for their wateriness. The length data does not include all the specimens collected, because this is a fragile species that is often damaged in samples. The measurements give below are based on good material collected using an insulated closing cod-end, which enabled specimens to be kept alive in a constant temperature conditions for several days.

60°N n Mean mm s.d. Range mm
Female 11 14.55 0.47 13.83-15.50
Male 17 12.27 0.76 11.33-14.00
A-1 7 13.18 1.34 9.33-12.50
A-2 6 11.00 0.41 7.17-8.17
A-3 3 6.25-6.67
52°N n Mean mm s.d. Range mm
Female 22 13.67 1.02 12.00-15.50
Male 27 11.79 0.90 10.00-13.50
A-1 17 10.48 0.76 9.67-12.00
A-2 3 9.03 0.10 8.92-9.17
A-3 15 7.38 0.41 6.67-8.08
A-4 8 5.95 0.41 5.33-6.42
A-5 6 4.25 0.33 3.83-4.83
44°-50°N n Mean mm s.d. Range mm
Female 58 14.15 0.49 12.8-15.1
Male 70 12.22 0.57 10.3-13.1
A-1 79 11.06 0.42 10.3-12.0
A-2 80 9.12 0.40 8.4-10.0
A-3 117 7.42 0.26 6.8-8.1
A-4 27 5.92 0.26 5.3-6.4
A-5 36 4.70 0.23 4.4-5.2
Southern Ocean n Mean mm s.d. Range mm
Female 26 17.29 0.91 15.5-18.7
Male 13 14.65 0.59 13.5-15.8
A-1 19 13.28 1.06 11.7-15.2
A-2 11 9.80 0.26 9.3-10.2
A-3 13 7.99 0.53 7.2-9.0
A-4 3 6.1-6.3
A-5 2 3.9-4.4

Map

Distribution map for Gigantocypris  muelleri SST key

Bathymetry

Sorry - there are no bathymetry data for this taxon.

Drawings

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Outline

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