Species of Planctoteuthis are usually rather small and very fragile deep-sea squids that are often badly damaged during capture. As a result, few species have been described. Unlike other chiroteuthids, the subadult retains the peculiar doratopsid paralarval tentacular club. Roper and Young (1967) suggest that Planktoteuthis is a neotenic doratopsis.
A chiroteuthid ...
- with antitragus but no tragus in oval funnel locking-apparatus.
- with a compact club not divided into proximal and distal regions by structure of protective membranes.
- without funnel valve.
- without photophores.
The type species, Planctoteuthis danae, was originally placed in a new genus, Valbyteuthis, within a new family, Valbyteuthidae, by Joubin (1931). Roper and Young (1967) placed Valbyteuthis in the family Chiroteuthidae noting the similarity of Valbyteuthis paralarvae to those of Chiroteuthis. Young (1991) recognized that some paralarvae of Valbyteuthis had been previously descibed by Pfeffer (1912) as members of his new genus, Planctoteuthis, within the Chiroteuthidae. Valbyteuthis, therefore is a junior synonym of Planctoteuthis.
- Subequal in length in adults; arms IV much the longest in young.
- Arms IV with relatively few suckers usually aligned in virtually single series.
- Club small, compact.
- Club keel absent in some species.
- Low protective membranes along both boarders.
- Not divided into proximal and distal regions by protective membranes.
Figure. Oral view of tentacular club of Planctoteuthis lippula, Hawaiian waters, 35 mm ML. Photograph by R. Young.
- Head with elongate neck and brachial pillar.
- Eyes commonly project ventrally from head.
Figure. Lateral view of head of Planctoteuthis lippula, Hawaiian waters, 35 mm ML. Photograph by R. Young.
- Funnel valve absent.
- Funnel locking apparatus oval with posterior bump (antitragus) (see Comments).
Figure. Ventral view of funnel locking-apparatus of P. danae, off California, 47 mm ML, showing posterior antitragus and no medial tragus. Drawing from Young (1972).
- Tail present (usually lost during capture) with appendages. Appendages undescribed.
The exact form of the antitragus in the funnel locking-apparatus is often a species-specific feature. Unfortunately this structure is difficult to see and lighting and angle of view can often give different apparent results. The character must be used cautiously. Compare the locking apparatuses of the following species:
Figure. Funnel component of the funnel/mantle locking apparatus of various species of Planctoteuthis. A - P. danae. B - P. levimana, 60 mm ML. C - P. lippula, 55 mm ML. D - P. oligobessa. Photographs by R. Young.
The species are compared in the following table.
|Arm IV suckers, number||Arm sucker dentition, arm I-III||Antitragus||Fin length||Club shape||Club keel||Distribution|
|P. danae||12-13||7-9 distal truncated teeth||Double. Lobes nearly equal||52% ML||Symmetrical||No||Trop. Pacific|
|P. exopthalmica = P. levimana?||10||?||?||width=36% ML||Symmetrical||No||S. Indian|
|P. levimana||6-8||Broad truncate teeth all around||Double. Lobes unequal||40% ML||Long, symmetrical||No||N. Atlantic, Trop. Pacific|
|P. lippula||25||>50 minute teeth, distal larger||Single or slight double. Low, broad||40-45% ML||Short, Asymmetrical||Yes||Atlantic, Trop. Pacific|
|P. oligobessa||2-4||25-35 blunt teeth, distal 2/3||Single. Slender||23-33% ML||Symmetrical||No||Trop. Pacific|
Water temperature and chemistry ranges based on 1 sample.
Depth range (m): 1321 - 1321
Temperature range (°C): 3.413 - 3.413
Nitrate (umol/L): 43.111 - 43.111
Salinity (PPS): 34.524 - 34.524
Oxygen (ml/l): 0.836 - 0.836
Phosphate (umol/l): 3.232 - 3.232
Silicate (umol/l): 140.335 - 140.335
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Life History and Behavior
The doratopsis paralarva of Planctoteuthis can be recognized by:
- Strong ventral projection of eyes.
- Few suckers on arms, tentacles (young doratopsis).
- Relatively small, tapering tentacles (young doratopsis).
- Reduced vesicular region on mantle (young doratopsis).
Molecular Biology and Genetics
Statistics of barcoding coverage
|Specimen Records:||2||Public Records:||2|
|Specimens with Sequences:||2||Public Species:||2|
|Specimens with Barcodes:||2||Public BINs:||2|
|Species With Barcodes:||2|
Planctoteuthis is a genus of chiroteuthid squid comprising five species, occurring worldwide in lower mesopelagic to bathypelagic depths in tropical to temperate waters. It has been suggested that members of Planctoteuthis are neotenic, retaining characteristics of the doratopsis developmental stage. This is marked in the retention of the paralarval tentacular club, unique among subadult chiroteuthids. Members lack both photophores and a funnel valve. The genus was originally placed within the monotypic family Valbyteuthidae, under the name Valbyteuthis. Similarities between the paralavae of Valbyteuthis and Chiroteuthis led to its inclusion in the family Chiroteuthidae. Eventually, Valbyteuthis was incorporated as a junior synonym of Plantoteuthis, citing previous descriptions of the paralarvae.
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