Ampithoe tarasovi Bulycheva, 1952

Shin, Myung-Hwa & Coleman, Charles Oliver, 2021, A new species of Ampithoe (Amphipoda, Ampithoidae) from Korea, with a redescription of A. tarasovi, ZooKeys 1079, pp. 129-143 : 129

Ampithoe tarasovi Bulycheva, 1952

Figures 4 , 5 , 6 , 7 , 8

Ampithoe tarasovi Bulycheva, 1952: 246, fig. 38. Tzvetkova 1967: 190.

Type material.

Male, collected by Tarasov from De-Kastri, Sea of Japan, 3 Aug. 1929.

Description.

Based on holotype male, 14.3 mm (re-measured along the midbody line from the tip of the rostrum to the posterior end of urosomite 3), deposited at the Moscow Museum, Russia (no. 1/21349).

Head (Fig. 4B ). Upper lip (Fig. 4C ) with mid-lateral notch on margins.

Mandible (Fig. 4D, E ) molar well developed, triturating; accessory setal row with 9 robust setae; palp apically setose, 3-articulate; mandibular palp (Fig. 4F ) article 1 shorter than article 2 (0.6 times article 2); article 2 shorter than article 3 (0.7 times article 3); article 3 long (3.3 times as long as wide), longer than article 1 (2.3 times article 1).

Lower lip (Fig. 4G ) outer plates forming a medial excavation, lateral lobe much longer than medial lobe; mandibular lobe curved laterally, rounded apically.

Maxilla 1 (Fig. 5A ) inner plate with 1 slender seta; palp well developed, with apical robust setae.

Maxilla 2 (Fig. 5B ) inner plate narrower than outer plate, with oblique setal row.

Maxilliped (Figs 5C-E , 6A ) outer plate with developed row of large robust setae along medial margin.

Pereon. Gnathopod 1 (Fig. 6B ) sexually dimorphic, smaller than gnathopod 2, carpus and propodus with numerous plumose setae on both anterior and posterior margins; coxa subequal to coxa 2 in length, broader than deep, anterior margin straight, anteroventral corner produced, rounded; basis longer than coxa, anterodistal lobe large and rounded; ischium anterior margin with large rounded lobe; merus posterodistal corner subquadrate; carpus about 2 times as long as broad, longer than merus, longer than propodus (1.8 times propodus), with posterodistal lobe slightly overlapping propodus, posterior margin straight; propodus broad, 1.4 times as wide as long, subovoid; palm acute, convex, defining corner rounded with 1 robust seta; dactylus subequal in length to palm.

Gnathopod 2 (Figs 6C , 7A ) sexually dimorphic; basis longer than coxa, with sparse slender setae, anterodistal lobe large and rounded, not reaching beyond ischium; ischium anterior margin with subquadrate lobe; carpus much shorter than propodus (0.3 times propodus), subtriangular; propodus narrow, 2.3 times as long as wide, subrectangular; palm transverse, with a sloped quadrate mid-medial hump and an apically rounded defining tooth on posterodistal corner; dactylus slightly overreaching palm, curved, robust, apically blunt, without unguis.

Pereopod 3 (Fig. 8C ) basis narrow; merus narrow; carpus about twice as long as broad.

Pereopod 4 (Fig. 8D ) basis similar to pereopod 3.

Pereopod 5 (Fig. 8E ) coxa simple and subrectangular. Pereopods 5-7 lost.

Pleon. Epimera 1-3 (Fig. 4A ) with lateral ridges; ventral margin of epimera 2 and 3 straight, with distinct tooth on each posteroventral angle. Epimeron 1 subrounded posterodistally, with tooth on posteroventral angle; epimeron 2 subrounded posterodistally; epimeron 3 straight and sloped posterodistally.

Uropod 1 (Fig. 7B, C ) reaching to end of uropod 2 rami; peduncle with 10 robust setae; inner ramus longer than outer ramus, with 5 marginal robust setae; outer ramus slender, about 6 times as long as broad, with 14 marginal robust setae.

Uropod 2 (Fig. 7D ) peduncle with 8 robust setae; inner ramus longer than outer ramus, with 8 marginal robust setae; outer ramus 11 marginal robust setae.

Uropod 3 (Fig. 7E ) peduncle much longer than broad (2.3 times width), 2.2 times as long as rami, with 3 marginal robust setae, marginal slender setae present, with 8 distal peduncular robust setae; rami long, about twice as long as broad; outer ramus shorter than inner ramus, with 2 large recurved distal robust setae and 1 dorsal robust setae, with lateral setal fringe; inner ramus with 6 distal robust setae, with 2 lateral robust setae both inner and outer margins, respectively.

Telson (Fig. 7F ) subtriangular, apically subacute, with small apical cusps, with 4 or 5 of lateral setae on both margins, and 2 pairs of lateral plumose setae, with 2 or 3 submedial setae on both margins.

Sexual dimorphic female, 15.3 mm.

Gnathopod 1 (Fig. 8A ) subequal in size to gnathopod 2; coxa about as broad as long, anterior margin concave, anteroventral corner produced and subacute; basis subequal in length to coxa, with sparse slender setae, anterodistal lobe large and rounded; carpus subequal in length to propodus (1.1 times propodus); propodus narrow, 2 times as long as wide, subtriangular; palm acute, straight, defining corner subrounded with 1 robust seta; dactylus slightly overreaching palm, inner margin crenate.

Gnathopod 2 (Fig. 8B ) basis shorter than coxa, with sparse slender setae, anterodistal lobe large and rounded, not reaching beyond ischium; ischium anterior margin without distinct lobe; carpus shorter than propodus (0.7 times propodus); propodus narrow, 1.6 times as long as wide, subrectangular; palm acute, defining corner subrounded with 1 robust seta; dactylus slightly overreaching palm, tapering evenly, apically acute, inner margin crenate.

Depth zone.

Sublittoral (0-24 m).

Distribution.

Peter the Great Bay, Sea of Japan.

Remarks.

This species has the following characteristics: the apical and medial lobes of the outer lobes are separated in the lower lip; the carpus of male gnathopod 1 is about 1.8 times as long as the propodus; the palm of the male gnathopod 2 has a sloped quadrate hump and posterodistal tooth. Bulycheva (1952) noted that A. tarasovi is very abundant in macroalgae and reefs in Petra Velikogo Bay and in the northern Sea of Japan.

Figures

Figure 4. Ampithoe tarasovi Bulycheva, male holotype A epimeral plates 1 - 3 B head C upper lip D left mandible E right mandible F palp of mandible G lower lip. Scale bars: 1 mm (A, B); 0.2 mm (C, G); 0.1 mm (D-F).

Figure 5. Ampithoe tarasovi Bulycheva, male holotype A maxilla 1 B maxilla 2 C inner lobe of maxilliped D outer lobe of maxilliped E maxilliped. Scale bars: 0.1 mm (A-D); 1 mm (E).

Figure 6. Ampithoe tarasovi Bulycheva, male holotype A palp of maxilliped B gnathopod 1 C gnathopod 2. Scale bars: 0.1 mm (A); 1 mm (B); 0.5 mm (C).

Figure 7. Ampithoe tarasovi Bulycheva, male holotype A gnathopod 2 B lateral view of urosomite 3 C uropod 1 D uropod 2 E uropod 3 F telson. Scale bars: 1 mm (A-C, E); 0.2 mm (D, F).

Figure 8. Ampithoe tarasovi Bulycheva, female A gnathopod 1 B gnathopod 2 C pereopod 3 D pereopod 4 E coxa 5. Scale bars: 1 mm (A-E).