Pseudaeginella carinaspinosa, Shin & Lee & Heo & Kim, 2023

Shin, So-Yeon, Lee, Chang-Mok, Heo, Jun-Haeng & Kim, Young-Hyo, 2023, First record of the genus Pseudaeginella Mayer, 1890 (Crustacea, Amphipoda, Caprellidae) with a new species from Korean waters, ZooKeys 1169, pp. 163-174 : 163

publication ID

https://dx.doi.org/10.3897/zookeys.1169.105901

publication LSID

lsid:zoobank.org:pub:B9BC8CE9-958B-422B-AFF8-0A4B1CCEDE4A

persistent identifier

https://treatment.plazi.org/id/73AE96B5-7084-4145-B655-890AE6400ECF

taxon LSID

lsid:zoobank.org:act:73AE96B5-7084-4145-B655-890AE6400ECF

treatment provided by

ZooKeys by Pensoft

scientific name

Pseudaeginella carinaspinosa
status

sp. nov.

Pseudaeginella carinaspinosa sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 Korean name: Deung-ga-si-min-dung-bae-ba-da-dae-beol-re, new View Figure 5

Type material.

Holotype, male, 4.1 mm, NIBRIV0000895338, South Korea: Geomun-Island, Geomun-ri, Samsan-myeon, Yeosu-si, Jeollanam-do, 34°01'08"N, 127°18'27"E, collected from SCUBA diving, depth 7 m, Y.C. Park, 5 November 2015. Paratype, female, 3.4 mm, NIBRIV0000904522 and 5 males, 5 females, DKUAMP202301, same data as for holotype.

Additional material.

1 male, Jongdal-ri, Gujwa-eup, Jeju-si, Jeju-Island, 33°29'29"N, 126°54'47"E, collected from SCUBA diving, depth 3 m, Y.C. Park, 5 October 2015; 2 males, 1 female, Jongdal-ri, Gujwa-eup, Jeju-si, Jeju-Island, 33°29'29"N, 126°54'47"E, collected from SCUBA diving, depth 3 m, Y.C. Park, 7 October 2015; 2 males, Namhyeongje-Island, Dadae-dong, Saha-gu, Busan, 34°53'04"N, 128°57'04"E, collected from SCUBA diving, depth 10 m, Y.C. Park, 16 November 2015.

Description.

Holotype, male, NIBRIV0000895338.

Body (Figs 2A View Figure 2 , 3A View Figure 3 ) slender, 4.1 mm long. Head with a projection dorsally. Eye small, round. Pereonite 1 fused with head, suture not present, with a projection dorsally; pereonites 2-5 with a pair of middorsal projections, pereonites 2-4 with a posterodorsal projection, pereonites 3-5 with ventral projections, pereonite 2 with two anterolateral projections, pereonite 3 with an anterolateral projection, pereonite 6 shortest, with a middorsal projection; length ratio of pereonites 2-7 = 1.00: 1.24: 0.99: 0.77: 0.32: 0.36.

Antenna 1 (Fig. 3B View Figure 3 ) slender, about 0.8 × body length; peduncular articles 1-2 with several setae; peduncular article 3 short; length ratio of peduncular articles 1-3 = 1.00: 1.32: 0.43; flagellum 14-articulate, subequal in length to peduncle, each article with 1 aesthetasc ventrodistally.

Antenna 2 (Fig. 3C View Figure 3 ) much shorter than antenna 1, exceeding the distal end of peduncular article 3; length ratio of peduncular articles 3-5 = 1.00: 3.24: 4.35; flagellum biarticulate, swimming setae absent; about 0.1 × peduncular articles 3-5.

Upper lip (Fig. 3D View Figure 3 ) rounded, notched midventrally.

Lower lip (Fig. 3E View Figure 3 ) well developed, smooth, without setae; inner lobe bilobed slightly (drawn from 4.2mm male).

Left mandible (Fig. 3F View Figure 3 ), incisor 5-toothed, lacinia mobilis 5-toothed, followed by 3 serrulate plates; molar present but reduced; palp triarticulate; article 2 about 1.6 × article 1; article 3 subequal to article 2 with a distal knob and setal formula of 1-5-1.

Right mandible (Fig. 3G View Figure 3 ), similar to left one, except incisor 6-toothed, followed by 1 serrulate and 2 smooth plates.

Maxilla 1 (Fig. 3H View Figure 3 ), inner plate absent; outer plate with 6 stout setal teeth apically; palp biarticulate, distal article with 3 apical robust setae and 1 subapical seta.

Maxilla 2 (Fig. 3I View Figure 3 ), inner plate with 2 long and 1 short setae apically; outer plate with 2 long and 1 short simple setae apically.

Maxilliped (Fig. 3J View Figure 3 ), inner plate small, with 2 simple setae apically; outer plate much larger than inner plate, with 3 simple setae apically and 3 simple setae medially; palp 4-articulate, article 2 longest, with 2 simple setae medially, distal article falcate, with a row of setules along inner margin.

Gnathopod 1 (Fig. 4A View Figure 4 ) small; propodus subrectangular, palm nearly straight with unequal simple setae, defined by 2 robust (grasping) setae proximally; dactylus falcate, bifid, with tiny accessory setae distally; length ratio of 6 articles = 1.00: 0.25: 0.43: 0.48: 0.84: 0.73.

Gnathopod 2 (Fig. 4B View Figure 4 ) attached midanterior margin of pereonite 2; basis elongate, subequal to propodus, slightly widening distally, with pointed projection on anteroproximal margin and subpointed projection on anterodistal portion; propodus massive, convex dorsally, width 0.5 × length, with a small robust (grasping) seta on proximal projection, palm irregular and serrulate, with a poison tooth mesially; dactylus falcate, inner margin weakly serrulate; length ratio of 6 articles = 1.00: 0.23: 0.18: 0.14: 1.13: 1.05.

Pereopod 3 (Fig. 4C View Figure 4 ) very small, rudimentary, about 0.1 × gill, uniarticulate, with 2 long and short setae distally; gill elongate-ovate.

Pereopod 4 (Fig. 4D View Figure 4 ) similar to pereopod 3.

Pereopod 5 (Fig. 4E View Figure 4 ) long and normal; propodus, palm concave and serrate slightly with small setae, defined by 2 robust (grasping) setae; length ratio of 6 articles = 1.00: 0.32: 0.69: 0.60: 1.11: 1.05.

Pereopod 6 (Fig. 4F View Figure 4 ) similar to pereopod 5, but more slender; length ratio of 6 articles = 1.00: 0.26: 0.72: 0.73: 0.94: 0.87.

Pereopod 7 (Fig. 4G View Figure 4 ) similar to pereopod 6, but more slender and serrate; length ratio of 6 articles = 1.00: 0.26: 0.70: 0.70: 0.95: 0.76.

Penes (Fig. 4H View Figure 4 ) elongated, situated medially, width 0.31 × length.

Abdomen (Fig. 4H View Figure 4 ) without appendage, with a pair of lateral lobes and a dorsal lobe; plumose setae on dorsal lobe missing.

Paratype, female (sexually dimorphic characters), NIBRIV0000904522.

Body (Figs 2B View Figure 2 , 5A View Figure 5 ) 3.4 mm long, generally as in male, but stouter than male, pereonites 3, 4 with rounded brood pouches. Gnathopod 2 (Fig. 5B View Figure 5 ) similar to that of male, but propodus more rounded than that of male. Abdomen (Fig. 5C View Figure 5 ) similar to that of male, but with a pair of plumose setae.

Remarks.

We compared the new species, Pseudaeginella carinaspinosa sp. nov., and related species of the genus Pseudaeginella (Table 1 View Table 1 ). Pseudaeginella carinaspinosa sp. nov. is similar to P. biscaynensis (McCain, 1968) and P. montoucheti (Quitete, 1971) in the following features: (1) head with an anteriorly curved middorsal projection; (2) antenna 2, peduncular article 2 with ventrodistal projection; and (3) pereonites 1-5 with dorsal projections. However, our new species is easily distinguished from P. biscaynensis and P. montoucheti by the following features: (1) gnathopod 2, basis with an anteroproximal projection; (2) pereonites 1-6 with strong dorsal projections; and (3) pereonite 6 with middorsal projection. Pseudaeginella carinaspinosa sp. nov. is also similar to P. colombiensis in the following features: (1) mandibular palp, article 3 with robust setae; (2) pereopods 3 and 4 with 2 setae. However, P. carinaspinosa is distinguished from P. colombiensis by the following features: (1) pereonites 2 and 5 with middorsal projections; (2) mandibular palp, setal formula 1-5-1; and (3) gnathopod 2, basis with an anteroproximal projection.

Etymology.

The species name is derived from the Latin carina (=back) and spinosa (= with spinose projection) with reference to the distinct dorsal spinose projection.

Distribution.

South Korea (Geomun-Island, Jeju-Island, Namhyeongje-Island).