Byblis longiflagelis Ren, 1998

Kim, Kyung-Won, Choi, Jae-Hong, Shin, So-Yeon & Kim, June Kim and Young-Hyo, 2024, Amphipod (Crustacea: Malacostraca) fauna of the continental shelf region in the Southern Sea of Korea, Journal of Species Research 13 (2), pp. 159-177 : 163-165

publication ID	https://doi.org/ 10.12651/JSR.2024.13.2.159
persistent identifier	https://treatment.plazi.org/id/039C8A02-FFCB-FC53-FCA4-FAC4CFA6F8F5
treatment provided by	Felipe
scientific name	Byblis longiflagelis Ren, 1998
status

Treatment

6. Byblis longiflagelis Ren, 1998 View in CoL

űnjñḑü경ăNjẹ (ṳạ) * ( Figs. 5 View Fig , 6 View Fig , 11F View Fig )

Byblis longiflagelis Ren, 1998: 177 View in CoL , Figs. 8 View Fig , 9 View Fig (cited from Ren, 2006); Ren, 2006: 167, Fig. 56.

Material examined. 1♂, Site 4, 17 August 2022; 1♂, Site 6, 17 August 2022.

Description. Male (MABIK CR00254534): Body ( Figs. 5A View Fig , 11F View Fig ) smooth, 11.1 mm long: Head ( Fig. 5A View Fig ) longer than pereonites 1 and 2 combined; rostrum short; corneal lens of eyes two paired, one pair located on upper distal end, the other located on apex of anterior cephalic lobe.

Gnathopod 1 ( Fig. 5B View Fig ), coxa gradually expended anteroventrally, ventral margin serrated, with plumose setae; basis elongate, subrectangular, with 5 long setae and 1 robust seta on posterior margin; carpus elongate, about twice length of propodus, with unequal setae on posterior margin; propodus elongate-ovate, palm subchelate; dactylus falcate, with a nail.

Gnathopod 2 ( Fig. 5C View Fig ) similar to gnathopod 1, but coxa subquadrate and smaller; carpus and propodus more elongated than those of gnathopod 1; length ratio of articles 2 - 7 = 1.00: 0.19: 0.31: 0.73: 0.30: 0.15.

Pereopod 3 ( Fig. 5D View Fig ), coxa similar to coxa 2; basis with simple setae on both margins; merus elongate, with plumose setae on distal half of posterior margin; carpus short, with 3 setae on anterodistal margin and 10 plumose setae on posterior margin; propodus slender, with several clusters of setae on anterior margin and 6 plumose setae on posterior margin; dactylus elongate and acute; length ratio of articles 2 - 7 = 1.00: 0.17: 0.65: 0.29: 0.28: 0.37.

Pereopod 4 ( Fig. 5E View Fig ), coxa subquadrate, posterior margin with posteroproximal excavation, posterior tooth subacute and produced backward; basis and merus subrectangular, with a row of simple setae on anterior margin, simple and plumose setae on posterior margin; merus to propodus subrectangular, slender, with plumose setae along posterior margins; length ratio of articles 2 - 7 = 1.00: 0.20: 0.81: 0.29: 0.24: 0.27.

Pereopod 5 ( Fig. 5F View Fig ), coxa weakly bilobate; basis subovate, broadly expanded, with 12 plumose setae and 12 robust setae on anterior margin, posterior lobe somewhat produced; carpus subrectangular, with 9 robust setae on distal margin and 1 robust seta on anterodistal corner.

Pereopod 6 ( Fig. 6A View Fig ) similar to pereopod 5, except coxa 6 with plumose setae anteroventrally and posterior lobe of basis weakly produced.

Pereopod 7 ( Fig. 6B View Fig ), basis expanded posteroventrally, ventral margin slightly serrated, with densely plumose setae, posterodistal lobe extending far beyond distal end of merus; length ratio of articles 2 - 7 = 1.00: 0.15: 0.18: 0.28: 0.23: 0.09.

Uropod 1 ( Fig. 6C View Fig ), peduncle subrectangular, subequal to outer ramus in length, with 5 dorsolateral and 5 ventrolateral robust setae; outer ramus longer than inner ramus.

Uropod 2 ( Fig. 6D View Fig ) short; peduncle subrectangular, longer than rami; outer ramus longer than inner ramus.

Uropod 3 ( Fig. 6E View Fig ), peduncle shorter than rami; both rami subequal in length, inner margin of inner ramus serrated.

Telson ( Fig. 6F View Fig ) quadrangular, with distally rounded corners, cleft not reaching to the middle, each lobe with 2 short setules on outer proximal margin, 1 short seta, and 1 robust seta subapically.

Distribution. Korea (south coast), China.

Remarks. Ren noted that Byblis longiflagelis is morphologically similar to B. orientalis by the following features: (1) antenna 2 elongate, overreaching body end; (2) telson trapezoid ( Ren, 2006). However, B. longiflagelis is distinguished from B. orientalis (different characters of B. orientalis in brackets) by the following features: (1) lower eyes located on ventral corner of anterior cephalic lobe (vs. located on distal margin of anterior cephalic lobe); (2) coxae 1 - 3 angled anterodistally, ventral margins serrated (vs. roundish anterodistally, ventral margins smooth); (3) coxa 4 posterior tooth moderately attenuated and subacute (vs. posterior tooth not attenuated); (4) pereopods 3, 4, dactyli longer than propodi (vs. dactyli subequal or short- er than propodi); and (5) pereopod 7, carpus subequal to propodus in length (vs. carpus shorter than propodus in length) ( Ren, 2006). In Korea, B. japonica is already known in the genus. However, B. longiflagelis can be easily distinguished from B. japonica as follows: (1) antenna 2 longer than body length (vs. shorter than body length), (2) coxae 1 - 3 ventral margins serrated (vs. ventral margins smooth). Our Korean specimens are in good agreement with the description by Ren (2006).