Promachoteuthis sulcus (first known as Promachoteuthis sp. C on this page) is known from a single, small (25 mm ML, sex unknown) but distinctive individual from great depths in the south Atlantic Ocean.
Brief diagnosis:A promachoteuthid...
- with nuchal fusion between head and mantle.
- with arm suckers much larger than club suckers.
- with tentacle base wider than arm base.
- with recessed club base and aboral tentacle groove.
- Arm suckers much larger than club suckers.
- Suckers in three series on all arms.
- At base tentacle thick, about 2x diameter of arm III.
- Tentacle stalk with deep groove on aboral surface.
- Club suckers tiny (0.014 mm diam), in numerous irregular rows.
- Sucker-bearing club recessed at tapering, proximal end; surrounding lateral and aboral tissue with thick folds.
- Tentacles heavily pigmented at base but not forming a well-defined band.
- Head fused to mantle in nuchal region.
- Fins terminal with anterior and posterior lobes. Each fin approximately circular in outline.
CommentsMore details of the description of P. sulcus can be found here.
Clubs were slightly abraided so the number of suckers in a transverse series could not be determined. The largest number of those present was 12 suckers across. The specimen is an immature female. The mantle was cut open prior to fixation by a previous investigator. The label in the specimen jar states that the ML is 40 mm; the squid currently measures 25 mm ML.
Type locality: 36°49'S, 12°17'W off Tristan Da Cunha, south Atlantic Ocean. Captured from WALTHER HERWIG at 1750-2000 m depth (open net).
Catalog Number: USNM 730702
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: female; immature
Preparation: Alcohol (Ethanol)
Year Collected: 1971
Locality: Tristan Da Cunha, South Atlantic Ocean
Depth (m): 1750 to 2000
Vessel: Walther Herwig R/V
- Holotype: Young, R. E., et al. 2007. A new genus and three new species of decapodiform cephalopods (Mollusca: Cephalopoda). Rev. Fish Biol. Fisheries. 17: 353-365.
Habitat and Ecology
Water temperature and chemistry ranges based on 1 sample.
Depth range (m): 1875 - 1875
Temperature range (°C): 2.700 - 2.700
Nitrate (umol/L): 28.259 - 28.259
Salinity (PPS): 34.757 - 34.757
Oxygen (ml/l): 4.735 - 4.735
Phosphate (umol/l): 1.945 - 1.945
Silicate (umol/l): 57.898 - 57.898
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
IUCN Red List Assessment
Red List Category
Red List Criteria
Promachoteuthis sulcus is a species of promachoteuthid squid. It is distinguished from related taxa on the basis of several morphological features: nuchal fusion between the head and mantle, much larger size of arm suckers compared to club suckers, greater width of tentacle base than arm base, a recessed club base, and the presence of an aboral tentacle groove.
P. sulcus is known from a single specimen caught by the German research vessel R/V Walther Herwig in an open net off Tristan da Cunha, southern Atlantic Ocean ( ), at a depth of 1,750–2,000 m (5,740–6,560 ft).
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