Atlas of Atlantic Ostracods
Taxon details
Porroecia parthenoda (Müller, G.W., 1906)
- Order:
- MYODOCOPA
- Suborder:
- Halocypridina
- Family:
- Halocyprididae
- Subfamily:
- Conchoecinae
- Size range (females):
- 1.5-1.9 mm
- Size range (males):
- 1.4-1.8 mm
- Depth:
- epi-/mesopelagic
Notes
395 records
Originally described from adult females collected at a wide range of stations in the tropics and subtropics of the Atlantic and Indian Oceans, Müller (1906) tentatively placed it in his ‘obtusata group’. The males remained unrecognised until Angel (1969) described males from material collected off Fuerteventura in the Canary Islands. He showed the species has close affinities with Muller’s magna group that were retained as Conchoecia species by Poulsen (1973). However, Poulsen placed it in a new genus Spinoecia, but without designating a type species. Martens (1979) split Poulsen’s genus Spinoecia into Obtusoecia and Porroecia, placing this species in the latter genus. In the absence of good generic definitions it must remain questionable as to whether this classification is appropriate. Angel (1972) later described another closely related species pseudoparthenoda from lower latitudes in the N.E. Atlantic, and earlier records may have confused the two species.
P. parthenoda is abundant in the tropics and subtropics of all oceans at shallow mesopelagic depths usually at 100-300m by day, and part of the population migrates up into the epipelagic at night. Living animals are translucent and very lightly pigmented. A diagnostic character of this species is that the left asymmetric gland opens on a small tubercle displaced anteriorly from the posterior dorsal corner (and the posterior hinge). In the sibling species pseudoparthenoda the opening of the left asymmetric glands is displaced anteriorly even further.
| Equator | n | Mean mm | s.d. | Range mm |
|---|---|---|---|---|
| Female | 117 | 1.76 | 0.055 | 1.58-1.86 |
| Male | 139 | 1.66 | 0.048 | 1.52-1.80 |
| A-1 | 52 | 1.25 | 0.034 | 1.16-1.32 |
| A-2 | 56 | 0.87 | 0.024 | 0.82-0.92 |
| A-3 | 41 | 0.62 | 0.018 | 0.58-0.66 |
| Bermuda | n | Mean mm | s.d. | Range mm |
|---|---|---|---|---|
| Female | 216 | 1.65 | 0.053 | 1.50-1.80 |
| Male | 216 | 1.51 | 0.041 | 1.40-1.60 |
| A-1 | 216 | 1.19 | 0.045 | 1.04-1.30 |
| A-2 | 214 | 0.84 | 0.025 | 0.74-0.92 |
| A-3 |
