Campylaspenis pisum ( Vassilenko & Tzareva, 2004 )

Akiyama, Tadashi, 2025, On some species of the genera Campylaspenis and Campylaspis (Crustacea, Cumacea, Nannastacidae) from the Sea of Japan (Northwest Pacific), with description of a new species of Campylaspenis, Zootaxa 5665 (4), pp. 543-562 : 548-553

publication ID	https://doi.org/10.11646/zootaxa.5665.4.3
publication LSID	lsid:zoobank.org:pub:99EC4A73-E1CC-4D3B-85B8-1840B0E34602
DOI	https://doi.org/10.5281/zenodo.16609982
persistent identifier	https://treatment.plazi.org/id/03C1879B-FFDF-FFD2-D0DB-FA44ACF274C1
treatment provided by	Plazi
scientific name	Campylaspenis pisum ( Vassilenko & Tzareva, 2004 )
status

Treatment

Campylaspenis pisum ( Vassilenko & Tzareva, 2004)

( Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Campylaspis pisum, Vassilenko & Tzareva, 2004: 13–16 View in CoL View Cited Treatment , Figs. 7–8 View FIGURE 7 View FIGURE 8 . Akiyama, 2014: 161.

Diagnosis. Females: Carapace compressed antero-posteriorly; each side with three distinct oblique ridges running parallel; 1st oblique ridge branch and re-unite on dorsal surface, making encircled region; pseudorostrum short, 0.04–0.07 times carapace length, upturned; eye lobe semicircular; frontal lobe with distinct transverse ridge. Maxilliped 3 basis inner distal corner projected; inner and outer margins of merus and carpus serrated, inner margin of propodus serrated. Pereopod 1 basis inner distal corner projected. Uropod peduncle 0.8 times pleonite 6, 1.8–2.3 times exopod, 1.9–2.3 times endopod; exopod 0.9–1.0 times endopod. Male. Pereonite 5 with a pair of large penial lobes; pleon with lateral groove; antenna 2 exceeding posterior end of pleon; uropod peduncle 0.8 times pleonite 6, 2.4 times exopod and 1.9 times endopod.

Material examined. 14 ovigerous and preparatory females, 1 adult and 4 subadult males, 11 juveniles (including dissected 4 ovigerous females, 2.9–3.4 mm, 1 preparatory female, 3.2 mm, 1 adult male 3.6 mm) ( NSMT Cr-22780), off Kasumi , northern coast of Hyogo prefecture, Honshu, the Sea of Japan, 35°46.11΄N, 134°30.94΄E–35° 46.57΄N, 134° 32.09΄E, 203–205 m (KT-11-9, St. K 2), 3 June 2011 ; 4 females, 2 subadult males, 9 juveniles (including dissected 1 ovigerous female, 3.2 mm) (NSMT-22779), off Toyama, northern coast of Honshu , 37°28.77΄N, 137°29.07΄E–37°29.53΄N, 137°28.63΄E, 207–258 m (KT-11-9, St. T2 ), 31 May 2011 ; 1 subadult male, off Noto Peninsula , 37°57.06΄N, 136°56.60΄E–37°57.04΄N, 136°58.23΄E, 201–203 m (KT-11-9, St. N 2), 1 June 2011 .

Description. 4 ovigerous females, 2.9–3.4 mm; 2 preparatory females, 3.2, 3.4 mm. Carapace ( Fig. 4A, B View FIGURE 4 ) 0.35– 0.40 times total body length, 1.18–1.29 times as width and 1.33–1.46 times depth, covered with short setae; each side with 3 distinct oblique ridges running parallel, 1st oblique ridge branch and re-unite on dorsal surface, making encircled region; 1st and 2nd oblique ridges connected by a short vertical ridge near lower margin of carapace; pseudorostrum 0.03–0.07 times carapace length, upturned; width of round eye lobe 0.11–0.13 times carapace width, 0.9–1.2 times eye lobe length; frontal lobe with distinct transverse ridge ( Fig. 7A, B View FIGURE 7 ); antennal notch obsolete; lower margin serrated. Pereon ( Fig. 4A View FIGURE 4 ) 0.48–0.70 times carapace length. Pleon ( Fig. 4A View FIGURE 4 ) 0.38–0.42 times total body length; pleon with weak lateral process on each side; pleonite 6 ( Fig. 5G View FIGURE 5 ) 0.8 times as long as wide.

Antenna 1 ( Fig. 4C View FIGURE 4 ), peduncle almost naked; basal article curved, 1.0–1.3 times articles 2 and 1.0–1.3 times article 3; article 3 0.9–1.1 times article 2; main flagellum tri-articulate, 0.8–0.9 times peduncle article 3; basal article 1.0 times combined length of articles 2 and 3; accessory flagellum uni-articulate, 0.3–0.4 times main flagellum article 1. Antenna 2 ( Fig. 4D View FIGURE 4 ) uni-articulate, with 6 tubercles on distal margin. Left and right mandibles ( Fig. 4E View FIGURE 4 ) broad at base; with robust 3 and 4 setae with many minute tubercles, respectively; molar process styliform, 3- or 4-dentate; lacinia mobilis 4-dentate; incisor process 5- or 6- dentate. Labium ( Fig. 4F View FIGURE 4 ) with short simple setae on tip. Maxilla 1 ( Fig. 4G View FIGURE 4 ) outer endite with 9 simple or dentate robust setae, lower 2 simple setae a little apart from the remaining setae; narrow endite with 5 ciliated, non-dentate setae; palp with terminal seta. Maxilla 2 ( Fig. 4H View FIGURE 4 ) narrow distally, with 3 terminal and 1 subterminal setae. Maxilliped 1 ( Fig. 4I, J View FIGURE 4 ) with 4–6 branchial lobules ( Fig. 4I View FIGURE 4 ); merocarpus with 3–4 simple setae on distal region and 3–4 short simple seta on inner margin; dactylus minute, 0.04–0.07 times merocarpus length ( Fig. 4J View FIGURE 4 ). Maxilliped 2 ( Fig. 4K View FIGURE 4 ) basis 0.7–0.8 times distal articles together; ischium with plumose seta on inner distal corner; carpus with 2 tubercles and 2 simple setae on inner margin; propodus long, with 1 long terminal spines; dactylus with 3 long terminal spines. Maxilliped 3 ( Fig. 5A View FIGURE 5 ) basis 0.6– 0.7 times distal articles together, inner distal corner projected, with 1–2 plumose and 0–3 simple setae; outer distal corner with 0–2 long plumose setae; ischium with 2–3 simple setae on inner margin; merus 1.1–1.3 times combined length of carpus and propodus, with 7–9 teeth and 7–9 simple setae on inner margin, and 2–4 teeth and plumose seta on outer margin; carpus with 3–5 teeth and 2–3 simple setae on inner margin, 2–3 teeth and a plumose seta on outer margin; propodus with 4–6 teeth and 2–3 plumose setae on inner margin and plumose seta on outer distal corner; dactylus with 3 terminal setae.

Pereopod 1 ( Fig. 5B View FIGURE 5 ) basis 0.7–0.8 times distal articles together, inner distal corner projected, with 2 plumose setae, outer distal corner with 0–1 plumose setae; ischium with 1–2 plumose setae on inner margin; merus 0.7–0.8 times combined length of carpus and propodus, with 1–2 plumose and 2–4 simple setae on inner margin, with 2–3 plumose seta on outer margin; carpus with 4–5 teeth and 2 simple setae on inner margin, 3 teeth and 2 plumose setae on outer margin; propodus with 2–3 teeth and 2 simple setae on inner margin, 3 plumose setae on outer margin; exopod flagellum of 4 articles. Pereopod 2 ( Fig. 5C View FIGURE 5 ) basis 0.5 times distal articles together, with plumose seta on inner distal corner; dactylus 1.4–2.0 times carpus, with 9–10 setae. Pereopod 3 ( Fig. 5D View FIGURE 5 ) basis 1.2–1.4 times distal articles together, with 2–3 plumose on lateral margin. Pereopod 4 ( Fig. 5E View FIGURE 5 ) basis 0.9–1.0 times distal articles together. Pereopod 5 ( Fig. 8F View FIGURE 8 ) basis 0.5–0.6 times distal articles together. Terminal setae on dactylus of pereopods 3–5 fused to the articles.

Uropod ( Fig. 5G View FIGURE 5 ) peduncle 1.7–2.0 times pleonite 6 length, 1.8–2.4 times exopod, 1.9–2.3 times endopod, serrated on inner margin; exopod 0.9–1.0 times endopod, with long simple terminal seta; endopod uni-articulate, with 3 spiniform setae on inner margin and long terminal seta.

Adult male, 3.6 mm ( Fig. 6 View FIGURE 6 ). Carapace ( Fig. 6A, B View FIGURE 6 ) 0.37 times total body length, 1.46 times width, 1.79 times depth, with few short setae; ridges on carapace similar to females; pseudorostrum ( Fig. 6A, B View FIGURE 6 ) 0.06 times carapace length; width of eye lobe 0.13 times carapace width, 1.2 times eye lobe length; corneal lenses absent; antennal notch shallow ( Fig. 6C View FIGURE 6 ); lower margin of carapace serrated. Pereon ( Fig. 9A, B View FIGURE 9 ) 0.66 times carapace length; pereonite 5 with large penial lobes (left lobe shown in Fig. 6A, D View FIGURE 6 ), longer than basis of pereopod 5. Pleon ( Fig. 6A View FIGURE 6 ) 0.39 times total body length, with lateral grooves; pleonite 6 ( Fig. 6M View FIGURE 6 ) 0.8 times as long as wide.

Antenna 1 ( Fig. 6E View FIGURE 6 ), peduncle basal article 1.2 times article 2 and 1.3 times article 3; article 3 0.9 times article 2. Main flagellum tri-articulate, 1.0 times peduncle article 3, with 1 aesthetasc on articles 2 and 3; accessory flagellum uni-articulate 0.4 times main flagellum article 1. Antenna 2 ( Fig. 6F View FIGURE 6 ) peduncle articles 5 2.0 times article 4; flagellum of 20 articles, exceeding posterior end of pleon. Maxilliped 3 ( Fig. 6G View FIGURE 6 ) basis 0.8 times distal articles together, inner distal corner with 2 plumose and 1 simple setae, outer distal corner with 2 plumose setae; merus 0.9 times combined length of carpus and dactylus, with 8 teeth and 8 short simple setae on inner margin and 5 teeth and plumose seta on outer margin; carpus with 3 teeth and 3 simple setae on inner margin, with 3 teeth and plumose seta on outer margin; propodus with 4 teeth and 3 plumose setae on inner margin and plumose seta on outer distal corner; dactylus with 3 terminal setae; exopod flagellum 5-articulate.

Pereopod 1 ( Fig. 6H View FIGURE 6 ) basis 0.8 times distal articles together, inner distal corner with 2 long plumose setae, outer distal corner with plumose seta; merus 0.7 times combined length of carpus and propodus, with 2 plumose and 3 simple setae on inner margin, 4 teeth and 2 plumose setae on outer margin; carpus with 2 teeth and 3 simple setae on inner margin, with 1 tooth and 2 plumose setae on outer margin; propodus with 3 teeth and 2 simple setae on inner margin, with 1 tooth and 2 plumose setae on outer margin; exopod flagellum 5-articulate. Pereopod 2 ( Fig. 6I View FIGURE 6 ) basis 0.6 times distal articles together, with plumose seta on inner and outer distal corner, respectively; dactylus 1.9 times carpus, with11 setae; exopod flagellum 6-articulate. Pereopod 3 ( Fig. 6J View FIGURE 6 ) basis 1.4 times distal articles together; exopod flagellum 6-articulate. Pereopod 4 ( Fig. 6K View FIGURE 6 ) basis 1.1 times distal articles together; exopod flagellum 6- articulate. Pereopod 5 ( Fig. 6L View FIGURE 6 ) basis 0.7 times distal articles together.

Uropod ( Fig. 6M View FIGURE 6 ) peduncle 2.7 times pleonite 6, 2.4 times exopod and 1.9 times endopod, with 9 plumose or ciliated setae on inner margin and 5 simple setae on ventral surface; exopod 0.8 times endopod, with 2 terminal and 2 sub-terminal setae; endopod uni-articulate, with 9 spiniform setae on inner margin and terminal seta.

Remarks. This species, originally described as Campylaspis pisum based on female specimens collected from northern coast of the Sea of Japan, 42°40΄9″N, 135°16΄8″E, 865–950 m, ( Vassilenko and Tzareva, 2004), is transferred to the genus Campylaspenis due to the presence of the large penial lobes in the adult male specimen. Other morphological characters of the Japanese specimens agree with the original description by Vassilenko and Tzareva.

Campylaspenis pisum is similar to C. sigeogamoi , another Campylaspenis species from the Sea of Japan. Campylaspenis pisum is distinguished from C. sigeogamoi by (1) a transverse ridge present on frontal lobe of carapace (not present in C. sigeogamoi ), (2) pseudorostrum very short, 0.035 –0.072 times carapace length, upturned (pseudorostrum not so short, 0.11–0.13 times carapace length, not upturned in C. sigeogamoi ).

Campylaspenis pisum is very similar to Campylaspis brevirostris Akiyama, 2014 except for the presence of penial lobes in males. Upturned pseudorostrum of both species is very short, 0.035 –0.072 times carapace length in C. pisum and 0.034 –0.039 times in C. brevirostris (based on the drawings of the 5 type specimens described in Akiyama, 2014). However, in addition to the morphological characters in Akiyama (2014), Campylaspenis pisum is distinguished from Campylaspis brevirostris by (1) relative length of basis to combined length of distal articles in maxilliped 3 and pereopod 1 are 0.6–0.8 for maxilliped 3 and 0.7–0.8 for pereopod 1 in females (0.9–1.0 for maxilliped 3 and 1.0–1.1 for pereopod 1 in C. brevirostris ), (2) finger-like process absent on propodus of maxilliped 3 in adult male (present in C. brevirostris , Fig. 6B, C View FIGURE 6 ).

Distribution. Russian and Japanese coast of the Sea of Japan, 865–950 m in Russia and 201–258 m in Japan.