|This is an abundant species in the Sea of Japan and the Sea of Okhotsk. How far it penetrates into the ocean is not known as most researchers have not separated it from the very closely related species, P. pacifica, which lives in the subarctic waters of the Pacific Ocean. There are references to its detection in the ocean in the coastal areas of northern Japan and the South Kuril Islands. [Bovallius, 1887]|
|Length of sexually mature females 9-17 mm; males somewhat smaller. [Bovallius, 1887]|
|This species is quite close to P. abyssorum and differs from it only in a few secondary structural details. The structure of the antennae is the same as in P. abyssorum but in the female antennae II are distinctly longer than antennae I, being about equal to the length of the head and the first three somites of the pereon. In the distal part of the basal plate of the maxillipeds a row of strong setae occurs, which are much longer in the middle, becoming shorter towards the ends; there are no setae on the outer margin of the outer lobes of the maxillipeds. The 6th segment of pereopods I is shorter than the 5th, its posterior margin finely denticulate and without submarginal setae; the claw is finely denticulate in the proximal part of the inner margin; pereopods III and IV are identical in structure; the short 4th segment broadens distally and the oval 5th segment is 1.5-2 times longer than it; the 5th segment bears long strong setae along the inner margin; the slightly curved 6th segment is barely longer than or equal to the 5th segment; the claw is long, slightly curved, and smooth. Unlike in P. abyssorum, of the last three pairs of pereopods, pair V is the shortest and pair VI the longest; the difference in total length of these pereopods depends mainly on the length of the 6th segment, which is 1.5 times longer than the 5th in pair and two times longer in pair VI; the posterior distal angle of the 5th segment in pereopods VI and VII bears one long strong seta; the claws of pereopods V-VI and V-VII are 2/11-2/9 the length of the 6th segment and bear a small fascicle of short setae in the proximal part of the anterior margin. The triangular-oval telson is 2/5-1/2 the length of the basipodite of uropods III. [Bovallius, 1887]|
Pereonites 1-5 fused in female, 1-4 fused in male. Gland cone in female produced anteroventrally, extending anterior to and overlapping epistome, with rounded apex; in male a rounded lobe produced ventrally. Gnathopod 1, article 2 with strong bulge on anterior margin, more pronounced in female; article 4 with 2 posterodistal spines; article 5 with 1.or 2 spines on posterior margin and 3 on carpal process; article 6 with single spine medially on anterior margin. Gnathopod 2 similar to gnathopod 1 except carpal process distinctly spoon-shaped and produced to about middle of article 6. Pereopods 3 and 4, articles 4 and 5 with single posterodistal spine; articles 5 and 6 with comb of spinules on posterior margin. Pereopod 5 of female and pereopods 5-7 of male, article 6 with comb of spinules on anterior margin. Pereopods 5-7, article 6 with straight. (Ziedler, 1992)
anterodistal spine overlapping dactyl.
|The young of P. japonica live mainly in the upper 50 m layer but adults are found at greater depths as well - right up to 500 m and, in the Sea of Japan, even deeper than 1,000 m, up to the near-benthic layer (~3,000 m). In the Sea of Japan crustaceans larger than 5 mm perform intensive diurnal migrations with an amplitude of about 400 m (Semenova, 1974). [Bovallius, 1887]|
Molecular Biology and Genetics
Barcode data: Themisto japonica
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Download FASTA File
Statistics of barcoding coverage: Themisto japonica
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
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