Phronima solitaria Guérin-Méneville, 1844

Phronima solitaria Guérin-Méneville, 1844 View in CoL ( Figs. 2 View Fig , 3 View Fig )

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Phronima solitaria Guérin-Méneville, 1844: 21 View in CoL ; Shih, 1969: 16, fig. 3; Zeidler, 2004: 12 View Cited Treatment .

Phronima custos Bate, 1862: 318 , pl. 51.

Phronima megalodous Stebbing, 1888: 1353 View in CoL , pl. 162.

Phronima atlantica var. solitaria Vosseler, 1901: 23 View in CoL , pl. 2.

Material examined. 1 ♀, dissected (appendages on one slide), NIBRIV0000920259, 2 ♀, DKUAMP202504, Jeju sea, 32°59 ʹ 53 ʺ N, 125°59 ʹ 43 ʺ E, 14 Jun 2019, by MOC- NESS net, collected by SH Choo. GoogleMaps

Description. Adult female (NIBRIV0000000000), body ( Figs. 2 View Fig , 3A View Fig ) 17.1 mm long, dorsally smooth. Head subequal in length to pereonites 1-2 combined; eyes well de- veloped, large ommatidia cover dorsal and lateral margins of head and small ommatidia cover ventral and lateral margins. Antennae 1 reduced to two articles. Pereonite 3-4 anterior margin with triangular process. Pleonite 1 length 0.69 × pereonite 7; pleonites 1-3, posteroventral corners pointed.

Gnathopod 1 ( Fig. 3B View Fig ) carpochelate; basis relatively long, slender; ischium short, length 0.17 × basis, posterior margin with a setule; merus trapezoidal, length 1.29 × basis, posterior margin with 2 setules, middle of posterior margin serrated; carpus subchelate, length 1.81 × merus, posterior margin produced and reaching half of propodus, projection serrated, distal corner with a robust setule; propodus narrowing distally, length 0.89 × carpus, anterior margin with 5 setule; dactylus short, length 0.17 × propodus.

Gnathopod 2 ( Fig. 3C View Fig ) carpochelate; basis subrectangular, relatively long, slender; merus trapezoidal, 1.24 × ischium, posterior margin with 2 setules, posterodistal corner serrated; carpus subchelate, length 1.86 × merus, anterior margin with a setule, posterior margin produced, anterior margin of projection serrated; propodus subrectangular, slender, length 1.28 × carpus; dactylus short, falcate, length 0.11 × propodus.

Pereopod 3 ( Fig. 3D View Fig ) slender; ischium subquadrate, length 0.22 × basis, anterior margin concave, posterior margin with 3 setules; merus length 1.95 × ischium, anterior margin with 3 setae, posterior margin with 6 setules; carpus subrectangular, length 1.68 × merus, anterior margin with 4 setules, posterior margin with 8 setules; propodus slender, narrowing distally, length 0.94 × carpus.

Pereopod 4 ( Fig. 3E View Fig ) similar to pereopod 3, but slightly elongated.

Pereopod 5 ( Fig. 3F View Fig ) enlarged, subchelate; basis subrectangular, slightly widening distally, anterior margin with 8 setules, posterior margin with 6 setules, posterodistal margin with distinct process; ischium length 0.14 × basis, anterior margin with 4 setules, anterodistal margin with acute process, posterior margin convex; merus length 1.69 × ischium, posterior margin strongly curved; carpus characteristic in form, longer than wide, length 1.99 × merus, anterior margin slightly convex, distomesial portion with single protuberance, protuberance narrow, strong, slightly shorter than carpal process, carpal process strongly produced; propodus slender, narrow, falcate, length 0.82 × carpus.

Pereopod 6 ( Fig. 3G View Fig ), basis subrectangular, with small acute process anterodistally, posterior margin with a setule; ischium subquadrate, length 0.14 × basis, with midan- terior process; merus subrectangular, length 1.64 × ischium, with minute anteroproximal process; carpus subrectangular, length 2.56 × merus; propodus narrowing distally, length 0.48 × carpus.

Pereopod 7 ( Fig. 3H View Fig ) similar to pereopod 6, but basis more elongated and propodus shorter than those of pereopod 6.

Uropod 1 ( Fig. 3I View Fig ), peduncle subrectangular, unarmed; outer ramus 0.54 × peduncle, medial margin with serration; inner ramus slightly longer than outer ramus.

Uropod 2 ( Fig. 3I View Fig ) shorter than uropod 1, peduncle subrectangular, inner margin with serration; outer ramus 0.61 × peduncle, medial margin with serration; inner ramus similar to outer ramus in shape and length.

Uropod 3 ( Fig. 3I View Fig ) subequal to uropod 1, peduncle subrectangular, slightly widening distally; outer ramus 0.63 × peduncle, medial margin with serration; inner ramus similar to outer ramus in shape and length.

Telson ( Fig. 3I View Fig ) small, entire, subtriangular, unarmed.

Distribution. Worldwide.

Remarks. Phronima solitaria Guérin-Méneville, 1844 is similar to P. atlantica Guérin-Méneville, 1836 and P. sedentaria (Forskål, 1775) in having pereopod 3 shorter than pereopod 5. However, P. solitaria can be distinguished from its congeners by the following features (different characteristics of P. atlantica and P. sedentaria in brack- ets): 1) head length subequal to pereonites 1-3 combined (vs. subequal to pereonites 1-4 combined in P. sedentaria ); 2) pleonite 1 length 0.69 × pereonite 7 (vs. length 0.84 × pereonite 7 in P. sedentaria ); 3) pereopod 5, carpal protuberance single (vs. bifid in P. atlantica ); 4) pereopod 5, carpal protuberance as strong as the carpal process (vs. weaker in both P. atlantica and P. sedentaria ); and 5) uropods 1-3, both rami subequal in length (vs. uropod 2, outer ramus longer than inner ramus in P. atlantica and P. sedentaria ). Our specimens are accorded with the pre- vious descriptions provided by Guérin-Méneville (1844) and Shih (1969).